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  1. #1
    FEP Super Member erratic50's Avatar
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    Default Foxbody T5 + 8.8 Driveline loss

    Has anyone taken a known performance crate motor or a custom build that you had dynoed to the rollers after it's installed for final drive wheel numbers?

    Ive heard a huge range of values for driveline loss over the years. I'm curious what others have experienced with a WC T5 and a 8.8 in a foxbody.

    Granted a person can always weigh it then take it to the drag strip to get a good estimate- I'm simply curious what others have encountered from a dyno perspective.

  2. #2
    FEP Super Member xctasy's Avatar
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    Yes, it was done in Australia by Chevy Off-road and Marine Engines in 1996.

    The Australian 5.0 was the 1992-1995 Mustang 5.0 or 1996-2001 Explorer engine. Ratings were the US engine, less 1.7% because you guys use SAE net.


    Your 235 hp SAE net SVT Cobra for 1993 was 268 hp DIN net, so go figure....

    For 1995, it was 221.3 hp DIN net, and with a T5 and 9 bolt 7-7/8" axle, it made exactly 175 rwhp.

    Factor reduction was 1.264.

    Same deal was done during the Dana 44/ 8.8 axle era, same hp loss, axle made little difference.


    Automatics, based on historical Australian Ford data using Stewart's Mustang Dyno from 1976 to 1981, yielded 1.63 to 1.41 reduction on non lockup automatic's with 7-7/8 to 9" axles.



    You guys get 1.40 for AOD/9"
    And 1.163 for Muncie M22/12 Bolt 8.8"

    http://www.hotrod.com/articles/ccrp-...in-power-loss/

    http://vb.foureyedpride.com/showthre...vs-engine-dyno

    https://fordsix.com/viewtopic.php?t=71753

    Note that in a drag race, net flywheel to rear wheel hp losses are different to chassis dyno verses engine dyno.

    Its the flywheel effect that creates the disparity, and automatics do much better at drags than manuals.

    All those "14-18% loss for manuals and around 19-24% loss from automatics" are true, but on a chassis dyno, the total loss is more like 27 to 60%, and it depends on transmission type, if it has a torque converter, and its stall speed. When you drag race a shift kitted auto, there is still a 5 to 6% loss in power over a manual. In addition, flywheel hp ratings for 80's Fords were SAE net.

  3. #3

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    We had a guy in another forum that installed a couple add ons to a s.o. cougar. He ran the dyno and then t-5. I beleive he hit around 90whp with the auto and around 120whp with the stick. Compared to a factory rated 150hp, it seemed believable to me.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  4. #4
    FEP Super Member xctasy's Avatar
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    Quote Originally Posted by Haystack View Post
    We had a guy in another forum that installed a couple add ons to a s.o. cougar. He ran the dyno and then t-5. I believe he hit around 90whp with the auto and around 120whp with the stick. Compared to a factory rated 150hp, it seemed believable to me.
    That's exactly what I'd expect. 67% loss for an auto, 25 % for a manual.

    Be aware that the difference is slush box torque converter stall ratio.

    http://vb.foureyedpride.com/showthre...-i-6-(TURBOED)

    Quote Originally Posted by xctasy
    Ford big 5.0 GT C5 and AOD has 2350 rpm, and 2.53:1
    Stock 4.9 4-bbl Cleveland is a C10, basically a C4 gearbox, and it confirms Stall Speed 1650 is 2.14:1 from my 1979 Australian XD Falcon book
    eg 1973 US Mustang Clevelands

    351C 2V, C4 Trans, Stall Ratio 2.14:1, Stall Speed 1500-1700
    351C 2V, FMX Trans, Stall Ratio 2.05:1, Stall Speed 1500-1700
    351C 4VCJ, C6 Trans, Stall Ratio 2.16:1, Stall Speed 2200-2400
    351C 2V, C6 Trans, Stall Ratio 2.05:1, Stall Speed 1500-1700

    The industry needs to address effect of stall ratio. As soon as the torque converter hooks up, there is still a 1 to even 5% slip factor.



    Three things.


    1. In essence:-

    On a chassis dyno, an automatic gearboxes losses are "imputed" as clutch slip, the effective gear ratio is impossible to determine unless you measure the speed of the tprque converter spinner. Its actually the actual torque converter speed difference(not its stall speed, but its actual stall ratio in 1.9 to perhaps 2.85:1 as determined in some SAE literature) that determines the effective gear ratio in third. That is why the automatic trans shows such a huge slew.


    Ford used to supply that info in the 70's for C4's, FMX's and C4's, but from the 1979 on wards lock-up clutch era, it became impossible to find, and is replaced with a nominal 1700 or 2350 rpm stall ratio which varied between engine type.

    The other methods of assessment were discussed at length by Car Craft, Hot Rod and David Vizard over the variances between the Moroso dream wheel and other 1/4 and 1/8 mile hp indicator tests like G analysts and cell phone converters based on Newtonian Physics. They assert the same thing. A drag raced car launches much better than the huge 70 to 40% losses indicate.


    2. Secondly.


    When you drag race autos and manuals on cars that hook up well at the drags, the auto usually almost matches the manual. That means the dyno losses are Newtonian Physics modelling issues caused by the kind of eddy current or counterweight and heat factors. Each chassis dyno (eddy current, inertial, hub mounted) is different, but due to the stall ratio, they always slew the off idle to 3000 rpm torque figures, and at any other point above. You can be confidant that they are always calibrated to the industry standard 5252 constant to determine rwhp, but the individual methods require a check on the gear they were in when tested, and the effective stall ratio (not stall speed) is never included on a chassis dyno plot, so it is always in error on any chassis dyno.

    As a f'r instance....On my 205 hp 5r55 equipped 98 Explorer, it was impossible to lock the car in third gear to dyno it, and it had 4WD sensor trac and a lock-up clutch, so some more modern combos are impossible to test unless you are able to jumper the shift solenoids to determine the torque multiplication. I converted to 27" wheels from the factory 31" 275/70 16's.

    Sadly, no-one in the industry corrects for overall EFFECTIVE gear ratio in third...tire speed has to be calibrated to get actual engine RPM. An electronic lock-up clutch auto could be in the wrong gear when tested. And you can be sure, the stall ratio won't be included


    5 speed auto 205 hp Explorer 4.0 SOHC's were quicker than 4 speed auto 215 5.0 or 222 hp Saleen XP8's.

    I got a constant 16,7 sec standing 1/4 mile with my 125000 mile 3700 pound SUV, which indicates a lot less drive train loss than 41% I'd expected a lock-up clutch auto to have.

    Best info I got was from a long time drag racer on Fordsix, drag races FE engines had a 390 supercharged Stang, swapped the C4 into his triple carb 250 66 Mustang and then did constant low 14's.

    We "argued" that doing 14's in a 2600 pound auto Mustang ment he had 220 hp, but he said the auto loss wasn't 41 to 63 % in a shift kitted C4

    He always uses 15% because drag racers use shift kitted and trans braked autos, and they behave just like manual transmissions with a heavy flywheel.

    3. Thirdly

    Chassis dynos with automatics miss critical torque converter stall and use constant speed launches. That's not how any car drag races the standing 1/4 or 1/8 mile.

    My summary is that even at 600 rpm per second, a chassis dyno isn't the same as a drag race, and that the offline and between gears shock loads are different to a dyno test. Add a torque converter, and its a whole 'nother ball game.

  5. #5
    FEP Super Member erratic50's Avatar
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    So if I'm understanding the numbers correctly, you need around 480 SAE net HP to get 400 HP to the wheels through an 8.8 and a T5. Would be interesting to see how close someone can get to this with a streetable N/A 302 CID combination. Looks to me like a build to rev to the moon situation to me.

  6. #6

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    Drag on all rotating parts increases substantially as speed increases which could be a factor.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  7. #7
    FEP Super Member erratic50's Avatar
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    Totally. Throwing CIDs at the problem would make it a lot easier as would a power adder. But what fun is that? Would be interesting to see someone put together a 400 rwhp 302 CID N/A setup. Old school these days for sure.

  8. #8

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    I've seen enough stock block motors split in half to know you don't need more then 302 ci. If I was to start all over I'd still go 347 though. Same power at lower rpms and maybe a touch more torque. If starting from scratch the aftermarket stuff all costs about the same too.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  9. #9
    FEP Super Member erratic50's Avatar
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    I about died laughing watching dyno pulls one afternoon. I don't remember the show but they took a stock 89 5.0HO out of a T-bird mileage unknown. They bolted it to a dyno paired with an A9L and saw 226 HP. I don't remember torque but it was around 300 as expected. Then they started adding nitrous via wet kits.

    They stopped trying to kill it when reached a 375 shot via 3 stages and a total of 650 HP and over 700 lbs of torque the damn thing didn't blow up!

    LOL

  10. #10

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    We had one guy that shot a stock s.o. 150hp motor with a 350 shot. He would run high 11's to low 12's. Had a low mile h.o. motor and wanted to blow up the stock one. It wore out the piston rings but lasted a couple seasons. The s.o. piston are actually forged from 86- 91 in all motors.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  11. #11

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    Quote Originally Posted by Haystack View Post
    I've seen enough stock block motors split in half to know you don't need more then 302 ci. If I was to start all over I'd still go 347 though. Same power at lower rpms and maybe a touch more torque. If starting from scratch the aftermarket stuff all costs about the same too.
    I resemble that remark. Split my stock roller block with a 347 . I'll never do another 302 based stroker in a stock block again. Of course then I bought a car with a 347, but it has an ecam and GT40x heads, can't really compare that to a Twisted Wedge 11r 190 custom cam combo. Behind a AOD it feels like half the power my other 347 had behind a 5 speed. Currently getting a 302 built with the 11r heads and a Buddy Rawls custom cam. It should be close to 400 at the crank.
    83 Mustang GT , A5 5 speed, 31 spline Cobra rear, LMR TRX, 302 11r 190 heads, Buddy Rawls custom cam

    86 Capri , 342 stroker , AFR 185 heads, Track Heat intake, 3.73 gears

  12. #12
    FEP Super Member xctasy's Avatar
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    Buddy Rawls is simply awesome. I have a special cup I drink from when re-reading his or Ethyl Cat's posts. (and I've had a few from BR on Ford Six)

    https://www.redbubble.com/people/dig...e-stupid?p=mug

    Just for me. As my mate said to me, I didn't realise I was such an arrogant, ignorant a-hole.


    I told him..."we've been telling you that for years, but you haven't listened... " (also a note to self)

    I am certain that you'll get a nice 400 rwhp package, 4eyedfoxdriver. You deserve the best.


    Drive train losses at top speed are different to transient state losses, and AOD's are designed to slip and make the glorious slushed excuteive gear changes themselves. Just the way Henry Ford intended it in 1903....

    The math, well, I've shown what I know. Not everyone travels at the 200 Club pace, but you see exactly the same peak power losses on manual gearboxes with 380 hp in a 3500 pound 1972 Falcon at 170 mph. Add an automatic, and it won't be down 1.63 units, but it sure will be on a dyno. We don't race dynos.


    In post on top speed via Clause 5,

    (Posts #10 and #18, http://vb.foureyedpride.com/showthre...-transmissions )

    using Kiwi David McMillan's required flywheel HP method, the 1997 automatic 146 mph Falcon GT with the 93 Cobra SVT spec engine with GT40P heads and Explorer block, it had an AOD with just a 1.21 drive train loss, as it required 208.5 rear wheel hp to make 146 mph with a 0.30 drag factor and 23.13 sq feet of frontal area.

    Its engine dynoed at 254 hp DIN net on Ford Australias test cell. So that's not the same as 1.264 (26.4%). So you sure do get aberations with auto's.


    You also get cars that CLEARLY aren't the same as there power rating, and that was certainly true of the 1 mph faster 228 hp Holden Calias Director 5.0. If it had the 252 hp engine with the Wade 169 276 degree high lift cam, I wouldn't have been at all supprised, but if it really had 228 hp, then the drive train loss is just 13.4%, for it takes 200 flywheel hp to make a 0.40 drag factor car with 21.20 sq feet of frontal area do 147 mph.

    Same issue with the same car in Unleaded, cataylsed form, with 184 hp, and a 132 mph top speed. It needs 138 rear wheel hp to do that. The 184 vs 138 hp loss is 33.3% for a T5 and 9 bolt 7-7/8" axle.




    The 1987 Areo Mustang gave 136 mph from 225 hp. 0.36 drag factor, 20.87 sq feet of frontla area, and at that speed, needs 162 flywheel hp to the rear wheels to cope with 17 hp of 136 mph wheel frictional drag. 225 hp divided by 145 is 55.5%.



    I've got it all in a spreadsheet, I'm just quickly explaining how the losses work. I might be out a rolling resitance here or there,

    That car should have been able to do 145 mph that day, but becasue of its 2.73 axle ratio and 0.675 5th gear, it's 1.97 overall gear prevented it presenting 225 flwheel hp at 4600 rpm at 145mph. At 4600 rpm, it was doing 136. And thats what wrong gearing does...it takes the shine off top speed. It still needed a 0.63 5th to do that. Funny thing is, that's just what the T5Z 0.63 5th gear does, creates an ideal 1.72:1 top gear.


    We now that every Aussie Fal;con XR8 with the Mustang engine can make 175 rwhp with a T5.


    So the Mustang that day wasn't as fast as a car with 225 real flywheel hp should be.



    That's the whole thing about automatics. We have dragsters with air clutches, and two element converter 8 speed 840 hp production cars today to get past the dreaded auto loss factor, but a straight hook up to a flywheel by a good T5 is still just a great way to fly. For a traction limited car, or for someone who insisted on breaking T5's, an AOD is also a sensational way to travel.

  13. #13
    FEP Super Member erratic50's Avatar
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    Hey - if you haven't grenaded multiple T5's in catastrophic ways, you haven't given it everything it has enough. Heck - that's maybe true even when the ol 5.0 or 2.3T is stock!

  14. #14

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    Yeah my 347 spit out a t5 relatively quickly, I was in 3rd gear and parts started flying. I gave Astro a call and now have no worries. Ironically my motor and tranny blew in the same spot.

    I love that cup. Buddy is awesome, I will be going to him for all my cam needs and recommend him to anyone needing a cam.

    I am certain that you'll get a nice 400 rwhp package, 4eyedfoxdriver. You deserve the best.
    Thanks.


    I would love to see the exact loss of my AOD . I can lay a guess that it's putting down around 250-275 and I would think the motor should be around 325 at the crank, but those are guesses. I'll have it at the track some point I'd imagine.
    83 Mustang GT , A5 5 speed, 31 spline Cobra rear, LMR TRX, 302 11r 190 heads, Buddy Rawls custom cam

    86 Capri , 342 stroker , AFR 185 heads, Track Heat intake, 3.73 gears

  15. #15
    FEP Super Member xctasy's Avatar
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    Its the engine vibration, transmission case flex, and variable traction that makes the basic World Classes 316lb-ft or whatever maximum momentary output torque (MOT) rating such a laughable lottery.

    Just like Ford rating the Coninuous Operating Torque (COT) / maximum momentary output torque (MOT) like this

    Ford 7.5 Rear 870 3,230<------Stock Fox 8.8"
    Ford 8.8 (28spline) Rear 1,250 4,600<------Stock Fox 8.8

    When actually its the 28 spline axles that govern how much curry you can poor into the pavement. The axle shaft is the first frainable piece if the axle center is doing its job.

    Ford don't rate axle shafts the way a drag racer does. They don't rate it that way probably because soomone would spend all there time trying it out.

    Ford Motor Company's Automatic Newton meter values used with the automatic 4 and 6 speed 4R44E/4W70R/5R55 etc rating of 440 Nm, 700Nm, 550 Nm [325lb-ft, 515lb-ft, 405 lb-ft, respectively], or Fords T9 5 speed Merkur XR4TI 205 lb-ft, Borg Warners 260 lb-ft non world class T5 or 310 lb-ft World Class T5, or Tremec's 440lb-ft rating...they are tested differently, but its the same idea...some one at Ford tests them in batches, and breaks the crud out of those suckers...

    Dexter "AD" ( for Abaddon or Apollyon the Destryer).

    He works in Lab Rev 9:11, singing "get up a git, git, git down..." snapping axles, main shafts and reporting back to the CEO...

  16. #16

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    When I was 16 I got my 86 cougar with its stock 150hp s.o. motor to indicate 136mph on the Speedo. Took a while though... surprised I lived through that car
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  17. #17
    FEP Super Member erratic50's Avatar
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    Yea - nobody but the people who have owned these cars, driven these cars, or have often been in these cars or raced these cars will tend to ever believe how fast these cars go - even in stock SO form in a Tbird.

    And the 2.73:1 rear gear, 0.68:1 OD 5.0L HO Mustangs - especially the SD VM1 computer EFI E6 cars that had their silencer removed and timing turned up - were (and still are) absolute rockets.

    Car and a Driver tested the Mustang in 86 or 87 and found it went 148 in 4th but bogged in 5th.

    My experience is this - throw in a tank full of premium fuel and a driveway tuneup and mine didn't bog in 5th any more. Quite the opposite. It pulled and quite readily. All this crap from a car equipped with an 85 MPH speedometer and totally pathetic brakes!

    How fast? The speedometer only went to 85. RPM calculators might venture a guess what most of us either suspect or know.

    These days I have a lot more power than stock and a 0.63:1 overdrive. Fast? You bet! Now I'm looking at swapping in 4.10's which will shed vast top speed potential.
    Last edited by erratic50; 04-19-2017 at 03:12 AM.

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