T5Z transmissions

[erratic50]

Last year I had my original 1986 T5 completely torn down and gone through - turning it into a T5Z. For those unfamiliar that's a 2.95:1 low gear vs 3.35, 2nd and 3rd are evenly spaced to still hit 4th at 1:1 just like the factory WC T5. So 1.94:1 vs 1.99, 1.32 vs 1.34, etc. The other thing interesting about the T5Z is the overdrive is 0.63:1. So basically think of it like a 6 speed but there's such a wide split that there's no 5th gear.

Building one or buying one is a bit of no expense spared type of operation because it doesn't work well without other changes.

The builder I selected has been building T5's since the mid 80's and has ran his mustangs with performance parts and a lot of nitrous as fast as low 10 second blasts with the transmissions he builds. He even took one out of his race car after a few full seasons of punishment and put it into his street car for a while to see how it would hold up also going the distance which I found interesting.

I hate how many T5's my old E6 headed tired 5.0 has completely trashed in its time. I've lost count and would have to go to my receipts file but I think my motor has been in front of 13 clutches and around 8 T5's. Yes they have all been abused with full power - stomp the clutch to disengage while my foot in on the floor then drop it style shifts. Shifting in anger is hard on everything but is fun and what I've always chosen to do with my car. The price has been more than transmissions at 2 rearends and over 50 pairs of tires and every mount the car has many times, etc. T5Z is intended to bring ratios closer and encourage lower rear gears both to help ease this.

I don't remember everything about what he did internally on my current T5 but it's running the full T5Z gear kit with all of the 1993 Cobra and aftermarket advancements/upgrades in a package he has found stays together the best for guys that are abusive.

one piece steel bearing retainer, the strongest stock style gear set Anthony has found through drag strip punishment, the best synchros he has found, a hurst competition shifter, etc.

I went Z this time intending to also complete a rear gear swap to something a lot more forgiving coming out of the hole. Something that I don't have to ride the clutch or risk bogging or blowing the tires off. But for now with the 2.95:1 low gear this T5 is nearly impossible to launch even for a veteran driver. I've done it well a few times but I don't want to know the 60 foot times.

I'm writing this commentary for those looking at the 2.95:1 gear T's or the 2.97:1 low/0.63:1 6th T56 setups - do the math on low gear ratio and plan accordingly for sure. A lot of guys running 1/4 mile say you need around a 12:1 low gear for the weight vs power levels around 400 HP if you want to rev up, hook, and book consistently. A 3.73:1 axle with a 3.35:1 low gear is a bit much at 12.49 and could require "wheels up" 1-2 shifts once NOS is added unless you increase rev range of the motor past 7000. Miss a gear and trash your car- yikes!

The he math says a 3.55 axle with a 3.35:1 is a little too high Cs the rule of thumb at only 11.89. That likely requires extra clutch slip at launch to avoid tire spin on the first hit, etc.

A 4.10 gets the 2.95:1 to launch with the "right" 12:1 ratio but you're limited on trap speeds because 5th is basically really 6th and useless in acceleration situations due to the wide spacing vs 4th. Final selection with a T5Z really depends upon what trap speed you want to run and how high your motor revs. For some a 3.90 gear with some clutch slip out of the hole is an option that will allow a little higher trap speeds if they totally run out 4th in the 1/4 mile.

Damn the actual performance I will say one positive that is fun - and made even more usual with the typhoon intake and better breathing everywhere else - is there is something special - perhaps even unnatural - about seeing and hearing an old foxbody come out of the hole and run past 60 mph before shifting the first time then hearing the 1-2, 2-3, and 3-4 all happening with tighter than usual spacing. It's pretty fun compared to a stock HO motor and stock T5 setup just because of how differently it behaves. 2-3 at 88, etc. My dad has been around my 1986 the entire time I've owned it and was absolutely blown away with the passenger experience behind this, fast or not the soundtrack is a blast.

Another thing I wanted to share about the behavior of a foxbody 5.0L EFI, T5Z, and factory rear gear combination is 5th gear. What I found after getting my car out on the interstate on a windy day is that the combination of wind and moderate hills with the long legged nature of a 0.63:1 overdrive was nearly more than even the grunt of the torquey old 5.0L can bear. I'm only running 1400 RPM at 70 and only 1500 at 80. It acted normal at 80+ and behind other cars but up some considerable hills on OD pushing a strong head wind plus going 70-75 was where I found my foot planted on the floor to maintain speed. Even with a MAF A9L standing in boosting torque it didn't love the low R high speed combination all that well. Add 300 more pounds of weight and I might have had to downshift my car in 5th for the first time EVER while on the open road going faster than 55.

Gas mileage wasn't terrible but I suspect would be better at 100 than at 75 just because of the torque curve allowing for a lot less throttle position.

Another thing to bear in mind - even with a 140 MPH speedometer the math with a 25.86 tire and a 2.73:1 rear shows the 140 mph speedometer is buried at 2800 RPM.

I know from some younger and dumber days that with a 0.68:1 when you run out of R's in 4th at just north of 160 if you hit 5th and mat it that a strong running 5.0L will keep right on pulling in 5th. The trick on a stock motor was remove the intake silencer and advance the base timing before you tried it and do it in a car with a 2.73:1 and a 0.68:1. I'm not so sure many motors turned up would be willingly pull a 2.73:1 with a the 0.63:1 OD up there. These days I am not about to test it anywhere to find out.

Verdict - gear it down! 2.73:1 or 3.08:1 is not enough T gear for a T5Z. A car built to go really fast would be better off with a T56 and a 3.08:1 axle ratio or the 2.73:1 with 0.68 T5. And performance wise, anything to get more torque below 4500.

One last lol on the 0.63:1 combined with the 2.73:1 and 25.86" tire...... RPM math says 4200 is 210 MPH. Insane as I know full well some of the guys here have the power to pull to there and right past.

[biz jet tech]

very informative, thanks for posting!

[Supersonic G.T.350]

Yeah, I'll be looking at 4.30's. AFM says that's the gear for my cam profile. We shall see. Yes, I have a T5Z.

[erratic50]

4.30's will do well off the line if you have the R's to get out past 'wheels up' land before you have to shift. Nosing over or missing a gear is very hard on a frontend when it slams back down. Taller rear tires help offset the steep gears out back a bit for sure. All a percentages, what works, and what fits game.

So much fun hangin hoops. Hangin 10.... lug nuts if you've converted.

A stock fox on sticky tires and clean prepped pavement with the sway bar disconnected would just barely pull the front left up in a lot of old 80's drag and street race footage. Hard to believe those guys were getting that while adding so little additional power. I've always wondered about what gears the guys doing that were running. Some were using built C4's or C6' with a transbrake and a high stall converter plus steep rear gears. They'd be totally wound out by the end of the 1/4. Fast, no. Quick- definately for the time.

[Broncojunkie]

Good info. Thanks for posting.

I'm curious as to how he's building these to hold up so well? The "z" spec t5 has, if I understand correctly, a tapered roller bearing for the front input shaft vs the needle bearings in other models. The other "z" difference is a sychro'd reverse gear and different gear ratios. But what this guy is building has upgraded "stronger" gearsets and upgraded blocker rings in addition to the factory style upgrades? I'm not nitpicking here, just trying to understand what upgrades are allowing this t5 to take so much abuse and not be blown to smithereens lol!

I have started tinkering with these t5's myself, and learned a few upgrades along the way. The best bang for the buck I've found so far is to find a t5 from a 99-04 v6 Mustang. Swap tailshaft housings with an older fox t5 if you want to retain mechanical speedo. Swap the speedo drive gear and retainer over. Swap the front input shaft and retainer from a fox (if you want to use the fox bell..if not, use an sn95 bell or even use the 3.8 bell, if you want to get fancy and go to an 11" clutch...but that gets more complicated). Obviously, upgrade to a steel input shaft retainer, billet steel cluster gear retainer, and set end play to a very slight pre-load.

The reason for this is that the gearset is about the strongest you can get without going to a "z" spec (not sure if there is actually a difference in strength between the 2). It is rated at 300 ft-lbs, which is the same rating as the later v8 t5's. We're talking 92(ish) to 95 5.0 t5. The v6 models, however, normally have much less wear than a fox or sn95 v8 t5, otherwise the two are interchangeable. I just haven't had any luck finding a good used v8 t5. With the upgraded bearing retainers and properly-set end play on both shafts, it should hold up to some pretty heavy abuse. Maybe not tko 600 strength, but a LOT cheaper, quieter, smoother-shifting, and lighter weight.

I plan on building one for the pace car I'm working on. It's getting a built 331 and should be making decent power.

I have had trouble finding any real "upgrades" as far as carbon fiber blocker rings go. It seems to me, they're all basically the same. To be honest, I'm not even sure they're not all made by the same manufacturer. I get a little confused when talking about aftermarket gears and shafts, as well. It seems the "oem" parts are about 3x as much $, but the "aftermarket" style (which may or may not be stronger) cost less? I have a few t5's lying around in need of rebuild and I'm tempted to throw one together using parts from all of them, but I don't think they'll produce what I'm looking to build for myself. I may just keep them for the occasional spare part here and there.

[erratic50]

Cobra T5's were 330 lbs rated from the factory AFAIK. I do not know the details of what was specific parts are used in his T5's but yet --- agreed - lots cheaper than going TKO. Tapered roller and a one piece steel bearing retainer are the very most critical parts AFAIK. After that its synchro and gear improvements.

I do know much of the secret sauce is not inside the transmission at all. Pilot bearing tolerances, rear main bearing slop, accuracy of the bell housing vs the design specs as many require thin shims at the bolts to get them to run completely inline with the crank and true.

The clutch design has to give a soft release and also have a spring design and compound that won't result in any chatter at all while still holding the power. Full engauges/disengauge has to work properly at max R's on the engine.

Manual clutch quadrant and adjustable cable are critical.

Flywheel vs release pivot point and clutch fork tolerances is critical. Too much forward movement before the release fork starts reducing pressure plate pressure and by the time its all the way to release pedal pressure is well past 150 lbs. Many aftermarket flywheels -- especially lighter than stock ones -- require a shim between them and the crank or an adjustable or shimmed pivot ball to make things work properly. You'll know immediately because you'll have the firewall adjuster all the way out and be well into the cable adjuster and still won't have good clutch disengagement with the pedal on the floor.

Rear control arms, motor mounts, trans mount, crossmember, U joints, etc, all have to be in excellent condition. A positive stop equipped properly adjusted shifter is critical. Low (numerically high) rear gears and lightweight flywheels and clutch assemblies are a key focus area. They survive by paying a lot of attention to detail on everything else.

With any T5, wheel shake or hop has to be corrected immediately as it severely trashes T5's - they simply won't put up with it.

I've been babying mine for the most part as some of the things in my car still aren't "right". I took out too many shims on the crank when I put in the new flywheel. I planned to spend a lot more time swapping it in, but the fact is my car was down and I needed it at the time so I patched it up with an additional cable spacer and am living with a heavy pedal. I still have some things left to do.

Time will tell how mine holds up.

Driver experience with the ratios of a T5Z is very different than it is with a stocker. Especially take off and when you're in 4th then all of the sudden you're running 0.63 of what you were before when you hit 5th.

Not for everyone, but for my purposes I like it.

IMO stock final drive ratio wit stock rear gears is just too high. There's no reason for having a car that will go so fast as there's nowhere you can drive it.

This is slightly off topic but I thought I should mention that once my car is nice again my next transmission will likely go away from the traditional T5 or TKO. I believe what I really want in the end is a Viper spec T56 6-speed. D&D performance has two options in a foxbody kit. I am looking at the 2.97:1 low, 0.75:1 5th, 0.5:1 6th.

This influences my decision to go to 4.10's now instead of 3.73:1 or 3.90:1. I don't love the FD even with my 0.63:1 OD but the 4.10 ratio is needed for launching a 2.95:1 1st gear.

I talked about the 1st gear ratio stuff before. That's only 1/2 of the picture of course.

Here's some quick FD ratio math to show how I reached my decision to use 4.10's.

2.73 * 0.68 = 1.8565 (WC T5)
3.27 * 0.68 = 2.2236 (WC T5)
3.55 * 0.68 = 2.4140 (WC T5)
3.73 * 0.68 = 2.5364 (WC T5)
3.90 * 0.68 = 2.6520 (WC T5)
4.10 * 0.68 = 2.7880 (WC T5)

2.73 * 0.63 = 1.7199 (T5Z)
3.27 * 0.63 = 2.0601 (T5Z)
3.55 * 0.63 = 2.2365 (T5Z)
3.73 * 0.63 = 2.3499 (T5Z)
3.90 * 0.63 = 2.4570 (T5Z)
4.10 * 0.63 = 2.5830 (T5Z) (FD about the same as WC T5 with 3.73:1 -- generally accepted as "livable")

2.73 * 0.50 = 1.3650 (V T56 - BTW check that out - holy cow what a ratio - good luck turning that!)
3.55 * 0.50 = 1.7750 (V T56 - BTW - again good luck!)
3.73 * 0.50 = 1.8650 (V T56 - note WC T5 number at the top is nearly identical!)
3.90 * 0.50 = 1.9500 (V T56 - less crazy than stock gears but still more "long legged" than a WC T5 and 3.27)
4.10 * 0.50 = 2.0500 (V T56 - still more "long legged" than WC T5 + 3.27)

If it wasn't for the "proper" 1st gear ratio being achieved with 4.10 I'd even consider 4.30:1 or 4.56:1. I did note though that you get into driveshaft and pinion RPM concerns before you'll run out of power with most 400 HP setups. The balance and pinion angle would have to be spot on for sure or it would vibrate like crazy.

[BaconB8]

My new T5Z just arrived and it's going into a Mustang with a 3:89 geared 9 inch. Is this combo close to the 12:1 ratio you're talking about for Hook-N-Book?

[BaconB8]

Also, I run a 'Z' in my 85 Saleen and like how it feels compared to the 3.35 in my Gt. The spacing is better.

[erratic50]

BaconB8,

There are a lot of factors in play with any car. As pointed out above cam is a big consideration. Flywheel weight, vehicle weight, etc, are factors.

When you multiply your 1st gear by your rear gear you get 2.95 * 3.89 = 11.4755. It's close to 12:1 - not quite as "steep" as the ratio a lot of guys with sick 60' times run with 3000 lbs and "moderate" 400 hp motors achieve. A little more power or additional clutch release time may be needed to get your desired result but it will be close.

If you're stubborn you can launch with any gear as long as there is enough power on tap to break the tires loose. The trick is controlling it and getting it to the ground.

I feel like I'm compromising a bit with my choice of 4.10:1. It's lower (numerically higher) than I really want to run but I don't want to swap more than once. It's a street car and I don't love the R's associated 4.10's and a .63:1 but it's going to be about like a 3.73:1 in a WC T5 car.

You will end up near the same spot low gear and 5th as a WC T5 with a 3.55 it looks like. 2-4 will be right together, 5th will be drastically farther away. A 37% drop in RPM.

I agree, I love the T5Z spacing. I'm usually done beating on it by the time 4th is done anyway. 5th is more or less just to get me to my destination at speed limit without breaking the bank on fuel.

[xctasy]

I cant drive 85 in my country, at 90mph its "put five on the fender, Mr Shapiro" teritory.


Although in Central Otago in a closed off road in 2012, I did an easy 96 mph at just 3600 rpm in my 1981 auto C3 equiped 3.3 2.73 axled in line six Fox, with about 91 hp at the flywheel.

As you can see from this coverage of 8.7 miles in 8 minutes at 66 mph average, the old hump never got over 2400 rpm.

https://www.youtube.com/watch?v=vyuAtgDlhL8

I think that's all that's really needed for relaxed cruising, 26.8 mph per 1000 rpm.

The T5Z sells the gear ratios that way because there are US traffic densities (like Huston grid lock) that won't cope with the 2.42 close ratio 1 st, and yet in the same place, interstates that let you do 85, so 0.80's won't sell.


So that's what sells.

The 2.95 ist and 0.63 5th is just a marketing ploy that happens to totally fit in with some of the permitted speeds you can drive in some states.

Apparently, you can specify other ratios.


For me, I'd go to the 0.80 Sebring over drive option, and gear the 3rd gear and axle ratio for maximum upshift rpm and therefore best mph through the traps doing the 1320 dash.

I favour the old fashioned 1965-1971 T10/Close Ratio Top Loader gear spacings with just a squwiff of over drive....just like early De Tompaso Panteras, rear drive V12 Lamborghinis and Ferrari Daytonas and DBS Aston Martin Vantages. All those cars, (like the 1971 Boss 351 with aftermarket headers, optional 3.25 gears), could do 120 to 140 mph in just 9 seconds. It was about gearing the cars for top speed to get the right 5th gear, and then for the 1/4 mile to get the right 3 rd gear and axle ratio.

That De Tomaso Pantera could do 160 mph with a longer 5th gear, but was a speed limited 138 mph at 6300 rpm for the first 18 months of production;, although even with a hydraulic cam, it'd rev well past 6500rpm.


Ford in the GT40's at Le Mans played with the 289/5 liters 0.85 top gearbox, it was also used in the 0.705 form to do 200 mph. In the later Pantera, the 0.85 ratios got swapped out 0.705's, and same with the 0.740 form in the Maserati Bora. They all used the GT40 gearbox.


5.0 Mustang engines have been eclipsing 5.8 Cleveland firebrands with the most basic mods for many years...Ford knew that since the Mustang Fox has so little frontal area, it could meet the performance of much bigger capacity, blunter 351 engined cars. Thats why the 0.70 SROD gearing from 1979 to 1983 Manuals with 3.08 axles. But 2.16 to 1.86/1.83:1 overall tops were as far as Ford liked to push it even with 140 to 225 hp engines.

3.08 x 0.70 SROD 5.0'S
2.73 X 0.68 Some 5.0'S
2.73 X 0.67 Some AOD 5.0's


The Pantera had a 2.97 over all with 0.705 5th, and just 3.58 with the Sebring style 0.85.

See my gearing/hp rant in

http://vb.foureyedpride.com/showthre...-Article/page2

My ideal gearing form computer trialling:-


Overall, 8.6:1 with 2.42:1 first and 3.55 axle. The exact sweet spot that woks so well with the early 69-70 Boss 302's. And close to the 9:1 that the wide ratio Toploader and 3.25:1 axle ratio 351c's gave the HO 4V Cleveland engines the same performance. In heavier cars, with big carbs, cams and compression. The milder Foxes with smaller ports and better carbs or fuel delivery overloads even the four shockie rear suspension, even with a Traction Lock/LimitedSlip Diff.

I still have an issue, the coomon kits is combined a default crazy 0.59:1 5 th gear, a 70% overdrive, but there are Sebring 0.80:1 kits which allow the 5th gear to be used as a top speed gear on a Fox. Without condeming people who like the stock T5 ratios (most of us here), if 'you' are silly enough to specifically ask for the standard 2.95:1 wide ratio set, the supplier will give you just that, but the ultra close ratio gear set is the included option for the price. Either way, it will take you out of of the granny low 3.35:1 first offered in some years.

http://www.jegs.com/i/G-Force-Transm...ductId=1343713



Updated Summary 31-10-2016_1229pm; Covers off what the recomendations actually are in case it wasn't obvious.


Recomended Option 1
http://www.jegs.com/i/G-Force-Transm...ductId=1343713
G-Force Transmissions GFT5242-93S
Synchronized T5 Gear Kit 87-93 Ford Mustang
G-Force Transmissions GFT5242-93S
Part Number: 468-GFT5242-93S
Synchronized T5 Gear Kit
87-93 Ford Mustang
Ist 2.42, 8.47:1 over all, mph per 1000 RPM = 8.7
2nd 1.53, 5.36:1 over all, mph per 1000 RPM = 13.8
3 rd 1.23, 4.31:1 over all, mph per 1000 RPM = 17.1
4 th 1.00 gear ratios, mph per 1000 RPM =21.04
Comes with 0.59:1 5th; Use Sebring
5 th 0.80:1, 2.8:1 over all, mph per 1000 RPM = 26.3
Use 3.5:1 axle ratio (final drive in 1:1 4th). Similar to using 3.55's
Gearing with Tires loaded 628.8 mm tall (24.76")
Unloaded static dimensions 642.6 mm tall (25.30")
Loaded wheel diameter is normally 2.2% smaller, or 97.8% of the unloaded tire specs.

RPM per mile normally includes the loaded wheel diameter

At 5500rpm change up, 48, 76, 94 mph, 116 mph and 145 mph


1/4 mile times in the 14 second area are 94 mph plus trap speeds, so close ratio gears can spark the car off line.

That 145 mph top wack which requires 311 flywheel hp net (245 rwhp net) with a 0.40 drag factor Mustang with 22 sq feet of frontal area.


That's so easy to do with a 5.0


At 2800 to 3100 rpm, you might have 260 lb-ft, and maybee 330 lb-ft at 4000 rpm if you car is worked, but it won't do that if the ratios aren't closer.


And finally, if you want to know how to gear a car for more than 141 mph and sub 14.6 second quarter miles, then the Aussies have been doing it from 1971 to 2016 with US/Aussie Made engines...Five 141 to 185 mph examples below, a sort of like a Jurasic Dyno Park!!!!

And the Holden Calais Director was what the 5.0 GT was modelded off, a 276 degree camed production 4-bbl carb car that dropped 14's and did 147 mph...

http://vb.foureyedpride.com/showthre...eplica-I-built

Probably right, although the Fairmont GT is one ULTRA rare son of a gun, one of a now only 19 in existance South African market export model, previously exported to the republic as a "re-coded" Falcon GT with Fairmont apointments as well as a pretty stout 300 hp SAE Gross 351c 4V 285 hp M code cam . A prety hard animal to tame. Manual cars were hydraulic lifter 15.5 second quarter milers with a 130 mph top whack, with that years 1971 GTHO, you got 300 degree solid lifter 350 hp SAE net engine with 14.6 second quarter mile capabilty, 13.9 secs with drag racing gears. Okay for 144 mph on the overun past where the 6150 rpm rev limiter kicked in.

Again we chewed up the miles and spat them out. In remarkably short time we were striking the long straights of the Hume about 140 miles north of Melbourne, and with the speedo steady on 125 mph I squeezed down still farther on the accelerator as the ribbon of road speared straight ahead.

The shaker heaved in the bonnet, the car sort of shrugged and the nose rose up even further from the road. It might have been a tiger kicked awake; the noise alone said that. The speedo needle went determinedly around the dial, and soon it was showing 144 mph. A true 141 mph.

But whoa! The engine started missing; fluffing and farting. For G""d's sake - the rev-limiter! we'd run right up to it. In top gear. A full 6150 rpm (the tachometer actually said 6700rpm; it was optimistic).

And if I kept my foot hard down that hoary great V8 just kept thumping away against the cutout, straining for even more. So once Uwe had shot some pictures over my shoulder, to prove it really was happening, I lifted off a fraction to back it off from the limiter at a neat 140 mph.

They picked up around 40 net horsepower over what Mick Webb dynoed in 1972, that was 350 hp. The 1972 RPO83 Phase Four made it to 170 mph at 6800 rpm claimed by Bill Santuccione or the similar 170 mph top speed Howard Marsden and David Bowden have claimed at 7200 rpm...that car, could do 140 mph at 7200 rpm in 3rd gear with the 6200 rpm rev limiter un hitched.

141 MPH at 6200 rpm (quoted from three other sources as 141 mph, but 144 indicated)
14.6 sec 1/4 mile at 95 mph
1971 Phase III GTHO FALCON 351, (Mustang 351 M code )
https://www.youtube.com/watch?v=GjDyl6Pjp1Q
https://www.youtube.com/watch?v=ZrVabs0SXZg
350 hp net at 6150 rpm, (Mick Webb, Hot 302S AND 351s 1990)
Cobra Jet 428/Boss 302 4160 780 cfm Holley 3310 4-bbl vac sec carb
300 degree solid lifter, 505 thou lifft cam
H-M Tri Y headers and dual exhasts
3.25:1 axle,
ER 70 14 tires,
Wide Ratio Top Loder 4 speeed
Ist 2.78
2nd 1.93
3rd 1.29
4th 1.00:1 (3.25:1 overall)

147 MPH at 4600 rpm
14.64 sec 1/4 mile at 95 mph
1985 Brock HDT Holden Calais 5.0 Calais Director
https://www.wheelsmag.com.au/feature...velvet-thunder
228 hp net at 4800 rpm,
725 cfm Rochester 4MC
304 cubic in Big Valvewith stock 276 degree XT5 Holden camshaft
H-M Tri Y headers
3.08:1 axle,
Pirelli P7 225/60 15 tires,
Ist 3.35,
2nd 1.93
3rd 1.29
4th 1.00,
5th 0.73:1 (2.25:1 overall)

146 mph at 4550 rpm
14.9 sec 1/4 mile at 92 mph
1997 EL Ford Falcon GT with 1997 Explorer Truck 5.0 with GT40P heads and GT 40 intake
https://www.wheelsmag.com.au/feature...n-the-autobahn
254 hp net at 4700 rpm
Non OBD II EEC V Engine management
5.0 Exporer V8 with big valve GT40P's and the E303 variation, non 256/266 cam
H-M Tri Y headers
3.27 axle
245/40R17 Yokohama A510 tires
BTR Borg Warner Ion LE 97 4stage AOD
Ist 2.39:1
2nd 1.45:1
3rd 1.00:1
4th 0.67:1 (2.19:1 overall)

157 MPH at 6150 rpm (quoted from three other sources such as Dr John Wright in Wheels 1983 as 156 mph.Unrev -limited, 170 mph was at 6700 rpm, as Bill Santuccione, the late Howard Marsden, and David Bowden [owner of two] have indicated is possiable)
1/4 mile unreported, but faster than 1971 car
1972 Phase IV GTHO FALCON 351,
https://www.youtube.com/watch?v=si1dSF0VN4s
390 hp net at 6150 rpm, (Ford Special Vehicles Bill Santuccione, Australian Muscle Car )
Cobra Jet 428/Boss 302 4160 780 cfm Holley 3310 4-bbl vac sec carb
300 degree solid lifter, 505 thou lifft cam
H-M Tri Y headers and dual exhasts (bigger diameter than 1970-1971 GTHO)
3.00:1 axle,
205/70 VR 15 Pirelli CN 36 tires,
Wide Ratio Top Loder 4 speeed
Ist 2.78
2nd 1.93
3rd 1.29
4th 1.00:1 (3.00:1 overall)

185 mph at 6600 rpm in 5th, not 6th gear
1/4mile 12.8 sec at 111 mph
2014 Ford Falcon FPV GT-F
https://www.youtube.com/watch?v=0zVTMAOiL-8
470 hp at 6000 rpm ( 537 hp at 6000 on overboost)/420 lb-ft 2500 - 5500 rpm
5.0 litre supercharged Boss V8
3.73 axle
275/30 R 19Y tires
TR6060 6-spd manual; or ZF HP26E 6-spd auto
1st 2.98 (11.11 overall)
2nd 1.78 (6.64 overall)
3rd 1.30 (4.85 overall)
4th 1.00 (3.73 overall)
5th 0.71 (2.65 overall)
6th 0.55 (2.05 overall)

[Supersonic G.T.350]

So with the multiplication that you mentioned 2.95x4.30, the radio ends up at 12.685. Should feel really stout, right?

[xctasy]

Last year I had my original 1986 T5 completely torn down and gone through - turning it into a T5Z. For those unfamiliar that's a 2.95:1 low gear vs 3.35, 2nd and 3rd are evenly spaced to still hit 4th at 1:1 just like the factory WC T5. So 1.94:1 vs 1.99, 1.32 vs 1.34, etc. The other thing interesting about the T5Z is the overdrive is 0.63:1. So basically think of it like a 6 speed but there's such a wide split that there's no 5th gear.

There is an alternate gear set that suits better, and that was what Option 1 above alludes to. The close ratio option is not an additional cost item as far as I can tell. Its not well known, and people don't really undestrand what closer ratio than the normal default gearing will do.


The so called Sebring top gear is just that, a usable top, which then allows you to optimise rear end traction by gearing it up to avoid wheelsin off line. Fords Fox four link really can hook up very well if done right.


Going back to the top end gearing selection.


From other cars of your ilk, cars in the same effective 10.41 pounds per cubic inches range your 86 is smack bang into.......All you need is a 2.65 over all top at the most, and to cross the quarter mile with 15% more revs than where your max power is developed.

That is 4.30 gears for 5650 rpm at 100 mph in 4th, still crusing at 85 mph at 3000 rpm if the 0.63 is used.

I'd order up 2.42:1 first close ratio gears for 10.4:1 overall.


But ideal gearing is still Option 1 above.

The early Euro Spec 4 speed 930 Turbo Carrera Porsche box had what the"experts" called odd ratios, that was a 260 hp flywheel car , and little frontal area and a clean shape, so it was geared for over 150mph, but the mph per 1000 rpm is the same as a 0.63 with 4.22's

In T5/ AOD or SROD terms, with 1:1 3rd, that's

2.54 1st (7.7 mph per 1000 rpm, 52 mph at 6700 rpm)
1.46 2nd (13.3 mph per 1000 rpm, 88 mph at 6700 rpm)
1.00 3rd (19.5 mph per 1000 rpm, 129 mph at 6700 rpm)
0.73 top (26.6 mph per 1000 rpm, 153 mph at 5750 rpm, effective final drive 3.71 x 0.73 = 2.71 )

Equivelent diff with 225/50 16's and adjusted to a 1:1 3rd gear, would be 3.71:1 gears.

That's sort of what the AOD or SROD where; Ford copied the Porsche idea.
2.73 AOD's and 3.08:1 gearing the SROD 5.0 had
4ths of 0.67/0.70,
3rd of 1;1,
2nd of 1.47/1.72,
1 sts of 2.47/3.07,

The matching 301.6 cubic inch to 3139 pound car combos you'd compare your Mustang to are

4 stage auto or manual 4 speed versions of the German Barnstomers were
6.9 450SEL Mercedes, 10.49 pounds per cube
928S Porsches11.3 pounds per cube
930 2.6 and 3.3 Turbo Porsches (14.58 to 15.18, but the 1.4 turbo factor makes em 10.41-10.84)

They all ran 2.65:1 over all top gears, all geared for perfect 1/4 mile and top speeds with just four gears.

[Droog]

We used to run 4.30's and 28" cheaters with both boxes. Seemed to work pretty well. My 89 LX was going high 12's with a 10-minute tune up, long tubes, no smog, Pro-5.0 shifter, no sway bars, no quads, 4.30's and ET Streets back in the mid-90's. A few years before that, there was a little old man running an 85 GT at the old outlaw track in Manhattan going 10.90's with a stock short, home ported Street Heats, some kind of old Weiand intake and a 780 Holley (off a 69 Boss 302), a home built 3.35-low box and 4.30's. Other than the heads and a Wolverine cam, it was very similar to my set-up.

Dunno why, but 4.30's always worked good in them.

[xctasy]

The Cheap Trick...if you want more gear you got it. Thank goodness Foxes just love tall, wide hides!


Because the car launches so nice that way, and your 4.30's are effectively 3.77's compared to a stock set of 24.5 inch tall when loaded 220/55 hr 390's.

Adding almost 4" to tire height makes your car think its got more gear.

Drag cars need weight transfer, and a track set up is normally pretty anti pin sharp handling, because all your doing is making it soak up the track conditions. And at even 110 mph through the traps, a smooth strip cuts up plenty rough.

Overall effective 1st is then 12.70:1, not 14.41.


Did that in reverse to my 98 XLT 4.0 Explorer. 3.73 gears with 275/70 R16'S are 30.5" loaded. Deflared its Jap Domestic market darth Vader polycarbonate, and popped in 26.5" 235/60 16's and suddenly my lumbering 28 mpg, 16.7 sec 1/4 mile Sploder did about city leaps like it ran 4.30 axles. Because, effectively, it did.


Launches were better, and it felt more stable with a lower center of gravity.

Fuel economy, corrected for speedo error, improved 2 mpg around town, and acceleration improved. The car was over geared at 65 mph, and fuel economy was slightly better, although most of that was reduced air resistance and frontal area reduction. With 0.75:1 5th gear, Effective Overall top was 2.8:1 before, but 3.23 after.

[erratic50]

Yes it will. What's best depends upon your power and weight. 12:1 is considered by many to be perfect for 3100 lbs and around 400HP at 6500.

[erratic50]

Agree that a taller has the same effect as a numerically lower (often called higher) axle ratio.

Tire height is a good tool for fine tuning. But know the contact patch on a larger tire is bigger but the trade off is it's harder to get the weight to transfer. Higher center of gravity too so bad if you are trying to corner

I was aware of the many T5 gear options. Yes, some remind me of the 60's M21 and M22's, etc. I picked my ratios knowing I eventually want a viper spec T56.

hopefully this post has helped someone out there get closer to their goal. Or at least avoid the oh crap moment with a T5Z if they aren't expecting it.

[xctasy]

Sounds like it works. That's what suits to tire as well. I guess effective best first gear is 12:1 for a 400 flywheel hp, 3100 pound car? Like 28" and 4.30"s for a good 105 mph + trap speed.

Some of those old 350-400 hp "tin top" Bathurst specuals were 8.3 to 9:1 first gear overall, not real good on the drag strip. Bast 1/4 mile times were with 3.9:1 gears and 2.78:1 firsts for 10.8:1, just like the old Boss 351's.


Seams like your right. The Option 1 gear set lookes like its too tall to fit into the known best launch gear criteria.


Your right, like the ages old GM Rock Crusher rules, M21 and M22, wide and close ratios, close for the circuit, wider for the drags.

[xctasy]

In line with you advise to get people to think over the T5Z's 0.63 and 2.95 ist gear, here is how you can use the formulas to check yor brain...

I think my off the line low gear overall calculation is a little agressive than it needs to be, but it is based on a boat towing algorithim

here it is from a few years ago 02-11-2013, 02:05 PM


http://vb.foureyedpride.com/showthre...your-engine-HP

The US cement highway has less road load than any pavement system on earth, with little yield and very low factors of friction, plus generally sensible
grade changes imposed by thinking road designers. This allows for the crazy over driven 5 th gear, and the 4 speed with two overdrives on the lastest Mustangs.

Clause 1, this is not the CAFE cycle pleaser.

1st gear should be optimised to allow a moderate legal trailer of about total gvw below 2 tons (4500 lbs minus the car weight, or about a 1300 pound trailer ) to be able to start off on a 12.5% boat ramp gradient.

You'll find 302 will cope with 2.78 and a 2.92 diff (8.12:1 overall),
but a 351 will take a 2.46 and 2.92 axle ratio and not show any ill effects (7.18:1 overall)).
A 250 might not like a 2.95 and 2.92 axle 8.61:1 overall)).
As such, the 5.0 will cope with a 2.32:1 ist if the diff ratio is low enough geared (high numerically; 8.12:1 above would suggest a 3.5:1 axle ratio ).

As an example, Ford Australia use this to ensure a car can pull a boat up a maximum gradient without burning out a clutch, and the overall ratios are engineering defined by a simple Weight times Gravity times sine theta calculation used in Caterpillar rim pull calculations.

Rover in England with there Five speed 2600, and Ford in Australia with some over geared 1982 Facon 200 cube 3.3's with 3.22:1 first gears and 3.23:1 diffs that wouldn't do that job (9.92 Rover 2600 and 10.40 overall Falcon 3.3 respectively),

so the first gears from then on got a lot less steep to avoid customer complaint. The Rover 2600 had a 3.08 diff and 3.22 first, and it was unable to do a boat pull.

That's why a Ford 2.3 four speed would use a 4.01, 3.80 or 3.65 first with a tall 3.08 axle ratio (12.35, 11.70,11.24:1 overall).

As weight to cubic inches ratio gets worse, the over all first gear has to go up to ensure a car can clutch through an LA grid lock.


The US CAFE gearing for the World Class T5 5.0 V8'S is way too wide for optimium acceleration, it's a 12 mile LA basin laboratory emissions and mpg pleaser.

Clause 2: Ford did the gearing better in the mid 60's, with ideal gearing that should be to copy the early close ratio T10 or Top Loader Mustang 289 close ratios,

Clause 3; 3rd gear should be optimised to take the car through the traps at the idelised mph for the flywheel hp plus a 10 to 17% allowance for over reving past the peak rpm speed. In this case 4600 rom peak power, to 5382 max. Although we know it can go to 6200 or more stock 5.0.

Clause 4: 5th should be a give and take highway gear, with 4th a performance ratio, and 3rd an ideal 1320 snap shot down shift.

Clause 5: Add the bare minimum over drive top to give best top speed, based on over all body drag,

The power need to make the top speed is defined as

The hp required for an given speed is calculated below but you must know the tire size in mm, the cd and FA.

Formulae for power due to drag and drivetrain loss is then able to be worked out with ease.

cd is the drag factor. A Pinto is about 0.48, an intermediate Falcon (66-70) about 0.48, a Thunderbird 0.35, a Fox Mustang 0.44 or 0.36 if its got an SVO body kit. Early 60's XK Falcons are quite slippery before the T-bird roof get things messed up...more like 0.40 than the 0.48 or so of a 65 Falcon. Early Sprints were likely to have the least drag.

FA is the frontal area. Then multiply cd by Frontal Area Note that a Pinto is about 20.2 ft2, an early (late 60's) intermediate Torino/Fairlane is 24.2 ft2, and a fat bodied Mustang (71-73) about the same. A Fox Mustang is around 20.8 ft2. A Maverick could be as low as 21 ft2 for an early tudoor, or over 21.5 ft2 for a post 74 dodgem bumper number.

cd*FA *mph*mph*mph * 1.27
. 147733

Then add tire loss

mm*lb*mph*8
. 58 036 680

Inputing all those 5 strictures into a 5.0 with 225 hp in a 3200 pound Fox with one driver and half a tank of gas and standard 225/60 15 tires, you can get the ideal

Trail 1 Axle/Diff Ratio/Gearing
2.73
1st 3.16
2nd 1.85
3rd 1.26
4th 1.00
5th 0.85

mph per
1000 rpm
1st 8.74 5382 47.0mph
2nd 14.86 5382 80.0mph
3rd 21.88 5382 117.8mph
4th 27.57 5382 148.4mph
5th 32.26 4600 148.4mph
65 mph in 5th = 2014 rpm


3rd cannot be easily lowered to give the ideal 15 second/95 mph quarter mile you could get with a 225 hp engine.

If you lower the axle ratio, you then have to extend the gearing in 5 th to make up for it.

Trail 2 Axle/Diff Ratio/Gearing
3.27
1st 2.63
2nd 1.64
3rd 1.26
4th 1.00
5th 0.714
mph per
1000 rpm

1st 8.74 5382 47.0
2nd 14.07 5382 75.7
3rd 18.27 5382 98.3
4th 23.02 5382 123.9
5th 32.24 4600 148.3
65 mph in 5th = 2016 rpm

Trail 3 Axle/Diff Ratio/Gearing
3.45
1st 2.50
2nd 1.55
3rd 1.20
4th 1.00
5th 0.677
mph per
1000 rpm

1 st 8.74 5382 47.0
2nd 14.05 5382 75.6
3 rd 18.18 5382 97.9
4 th. 21.82 5382 117.4
5 th 32.23 4600 148.3

65 mph in 5th = 2016 rpm

This show show you can widen the ratios for tall axles, and narrow the ratios if yoy use short axle ratios. If you over cam, with a more aggressive cam, the difference between the max rpm and the power peak rpm can allow you to run those exciting 3.73 and 4.1 gears

After all that, you can use this Clause 6, mpg calculator

http://vb.foureyedpride.com/showthre...4637-400M-swap

I've got a program the calculates open road miles per gallon at any speed , similar to Bowland And Grippos http://www.bgsoflex.com/mpg.html

His isn't based on engine capacity or gearing, it assumes everything is optimized for 100% efficency at the best Brake Specific Fuel consumption around , and doesn't allow for torque converter loses like mine does (even locked up, there is slip), so at 65 mph, you won't get the 24.91 mpg they claim at 65 mph, or the 25.85 at 62 mph.

Bowling's Vehicle MPG Estimator, a peak US MPG at speed calculator

Input Parameters Are the Following: (1984 LTD wagon. It's originally a 3.8L/AOD/7.5", planned 400 C6/2.73:1 7.5")
Coefficient Of Drag = 0.4800
Frontal Area = 20.8 Sq. Feet
Vehicle MPH = 62
Vehicle Weight = 3200 Lbs.
Tire Pressure = 32 psi.
Brake Specific Fuel Consumption = 0.0667 gal/hp-hr.
Drivetrain Horsepower loss = 12 (from the Clause 5 formulae above)
Computation Results:

Computed Drag + Drivetrain Horsepower is 36
Engine Fuel Consumption is 2.40 gal/hr
Engine MPG 25.85

As an estimator, is a great bit of program though!

My program only uses 62 mph, as it based on an Aussie Australian Standard calculation for chip seal/tar macadam roads , and I don't want to rearranged the 12 inputs to suit any speed just yet.

.......

If you want a very realistic estimated mpg for your combination at 62 mph based on your planned 5th gear verses what you have now, I can run the six clauses through. The formulae I use are from Kiwi Landspeed Record and Bonnville salt flat team the Mc Millans from Honda Data, and the US MPG from Snooks FISA Efficency Formula, a very close model at 62 mph. David Vizard did a road load variant of it in Car Craft

The ideal gearing for economy was cracked back in th 50's but we had to wait till the late 70's and early 80's for the formula to be re-arranged for best miles per gallon for a given average cruise speed. It is based on the from the Index of Thermal Efficiency, found in French Grand Prix and English RAC litrature by Hodges,

and was revised in 1980 for the Australian Total Economy Run, to use the average frontal area and drag fact for a lates seveties, early 80's car. See http://www.snooksmotorsport.com.au/i...d=31&Itemid=39

Here is my computer out put for a 3.3 and 4.1 engine in a Fox Mustang, using the Snook variation on the Index of Thermal Efficiency

You can calculate it for any pre 1983 passenger car without a wind cheeter body.

The method eliminates different frontal areas, tire drag and variable drag co-efficents, and is based on a coarse chip road surface, so it works for non wind cheeter boxy Mustangs, Falcons and sedans and wagons driven in non freeway conditions.

[size=8.5]mpg@62mph =* 1/(140 L/M act + 0.006W + 5)*100*2.2588
*********************** 3.540062

Where:*** L = the engine swept volume in liters, calculated as follows:
******************** Bore in mm*Bore in mm*Stroke in mm*No of Cylinders*0.78543691
************************
************** M act = mph per 1000rpm in the highest available gear, using normal driven wheel tire*
********************* placard details as follows:
**************************** ****************** ****************
*******************(Tire section*Aspect ratio as decimal)+(Tire section*Aspect ratio as decimal)+Wheel diameter in inches*25.4
1.022
******** Then multiply the result by 3.141 * 60, then divide by the diff ratio, and multiply by the top gear ratio

********************* Note: If auto,atic, 15% allowance for slippage was allowed for automatic transmissions,
********************* and the result of M is mulitiplied by 0.85.
This is because a T5 and 7.25 to 9" diff takes 26.5% power from the engine,
a C4 and 7.25 to 9" diff takes 31%. Difference in power loss from a manual to an automatic is usally 0.85

*************** W = weight of the vehicles in pounds, plus the ballasted weight of the
*********************** one driver and same weight passenger (200 +200 pounds and full tank of advertised fuel US Gals times 6.073 pounds).
Divide by 2.2046223[/size]

Those figures above for

the 1981 3.3 Mustang SROD 4 speed , 3.08:1 diff, 0.81:1 top gear(overdriven)= 28.5 US mpg at 62 mph on a 2.49:1 overall final drive
the 1981 3.3 Mustang C3 Auto 3 speed , 2.73:1 diff, 1:1 top gear =24.7 US mpg at 62 mph on a 2.73:1 overall final drive
the planned 1981 4.1 Mustang AOD 4 speed , 2.73:1 diff, 0.67:1 top gear = 27.2 US mpg at 62 mph on a 1.83:1 overall final drive

That last one is like a 1979 to 1982 4.2 V8 with a 1.83:1 diff ratio. If it was lowered to the factory 2.47 or 2.26, and rerun with a 4.2 engine, the fuel consumptionat 62 mph would be 22.4 or 23.7 mile per US gallon at 62 mph.

I re-ran it with the 4.2 4-bbl and AOD with 3.45 diff and got 23.4 US mpg at 62 mph.


The above Capri 4.2 with AOD combo with a 2.31:1 overall final drive would have done pretty well.

The lock-up clutch sure would have helped too. If you can employ the lock-up, there is a potential saving beyound that, maybee an extra mpg at 62mph.

Oh, and a 2.3 with T5 running just a 3.45:1 diff gets 38.6 mpg at 62 mph using the same information.

Which is what it got one up at 55 mph in the CAFE Highway figure. 38 mpg..



The point is that as an engine gets bigger, it can carry higher gearing, and to do that, the camshaft duration and lift can get dropped. A 4.2 runs 244 degrees of duration and has maximum power and 195 lb-ft of torque at 2200 rpm, which is very low in the rev range. At 100 mph, its only turning 3100 rpm with 2.26:1 gears, so its pefectly geared for 108 mph with 115 flywheel hp.

It comes from the above formulae above, and it works.

[erratic50]

My saleen build ended up with a G-Force kit with 2.95:1 low and 0.59:1 overdrive with a 3.55:1 rear gear. Same FD ratio as a 3.08 with a 0.6D and lots more fun 1-4 before i decide to behave....