1st run in 86 GT, low MPH (in my opinion) any ideas?

[v8stang289]

Hey guys, I ran my 86 GT for the first time a few weeks ago. First run was terrible, second was a little better. But I feel my mph was low for the cars mods

This is my setup:

86 GT 5.0/5-speed
stock 89 shortblock (re-ring and new bearings)
96 explorer GT40 heads -F3ZE casting- with mild port and polish (cleaned up bowls, smoothed transition etc.) with Trick Flow springs
stock rockers
9333pt felpro head gaskets
TFS-1 Camshaft installed dot to dot
Edelbrock Performer EFI intake with Edelbrock 7220 gaskets
65mm explorer TB
67mm FMS egr spacer
Stock 55mm MAF
Motorcraft copper plugs
Ford Racing 9mm plug wires
Accel cap and rotor with brass terminals
Cold air intake with K&N conical filter in inner fender
Flowtech shorty headers, 1 5/8" primaries, 2.5" ball flange
off-road 2.5" H-pipe
Flowmaster 2.5 cat back
A9L computer
12* initial timing with spout removed
Taurus 3.8 electric fan ( with 3G upgrade)
Stock T-5 (3.35 first gear)
8.8" with 3.73 gears and carbon fiber clutches
225/55/16 falken street tires on pony wheels.

Car should be close to stock weight, has A/C, no smog, stock sway bars are on and hooked up, stock suspension with replacement shocks/struts.
Runs and idles good, no smoke, doesn't use oil.
Car was at operating temp ~180* at the time of runs with 1/2 tank of fuel and 215 lb driver

The first run was bad, I spun like crazy in 1st and 2nd, missed 3rd, and ended up with a 15.6 at 94.17
second run was a little better, not as much wheel spin, ran a 14.3 at 93.96

Based on what I've seen my friends cars do, and what I've read, I was expecting closer to 100 mph trap speed. Is that unreasonable?

My buddy has a 91 lx hatch, with nearly the same setup other than a b-cam, and he traps 102.

I did have to replace the battery before I went to the track, the car sat for a few hours with no power to the ECM, so it probably lost any data/memory it had from the current setup. Could this have affected my trap speed?

Any ideas on this? or am I asking too much from this setup?

here are the slips from the 2 runs.

[86GT2r]

You should have a higher trap speed, my vert stock with 2:73 gears will run 93 at the end of the quarter mile.

[v8stang289]

You should have a higher trap speed, my vert stock with 2:73 gears will run 93 at the end of the quarter mile.

That's what i'm thinking. I wonder what my issue is....

[brianj]

What gear are you in and what rpm when you cross the finish?

[v8stang289]

What gear are you in and what rpm when you cross the finish?

3rd gear at about 5800 if I recall correctly

[brianj]

Hmm. With 3.73's, I'm running 6000 in 4th. Of course, i have no idea the gearing im my t5, it was in when i bought the car.

[STANGMAN116]

Higher timing maybe?

[brianj]

Next question, what is your TOTAL timing, and what rpm is your timing all the way in?

[306gt]

Your Mph is what completely stock 5.0L's run. My 88 with the GT40 top end and stock cam traps 102 mph. on regular street tires. I'd say something is wrong. I would start with a compression test first and then make sure all the tune-up parts are good. Plugs, wires, cap, rotor, etc. Then move on to timing, fuel pressure, etc. How does it run? any issues?

[v8stang289]

Hmm. With 3.73's, I'm running 6000 in 4th. Of course, i have no idea the gearing im my t5, it was in when i bought the car.

Are you sure? 6000rpms in 4th with 3.73s and a 26" tall tire would be ~124mph, with a 1:1 4th gear, but I believe all t-5's have a 1:1 4th gear.

Next question, what is your TOTAL timing, and what rpm is your timing all the way in?

Not 100% sure of the total timing since it's fuel injected and the timing is computer controlled. I *think* the A9L has 20 degrees of advance in by around 4000 rpm, so with 12* initial I should have about 32* total by 4000rpm. I may be wrong on that so please correct me if anyone knows.


I'm wondering if clocking the MAF will help since I have a fenderwell intake with a significant bend before the MAF.


Thanks for the input so far, keep it coming!

[v8stang289]

Your Mph is what completely stock 5.0L's run. My 88 with the GT40 top end and stock cam traps 102 mph. on regular street tires. I'd say something is wrong. I would start with a compression test first and then make sure all the tune-up parts are good. Plugs, wires, cap, rotor, etc. Then move on to timing, fuel pressure, etc. How does it run? any issues?

Yeah that's what worries me, I feel it should easily be 100mph. The car runs fine and feels strong, will spin through first and second and chirp in third. All the tune up parts are definitely good. Timing is 12* bdtc initial, fp is at 38 psi. I'll check compression next weekend and see what I've got there, but I believe its fine. I wonder if it could be a partially clogged injector or something.

[brianj]

Quite sure of the 4th/ 6000 rpm.. I have dozens of runs in this car. It actually runs out of steam about 50 feet before i cross the traps. Gt40 heads like around 34 degrees total, and they like it in by 2500-3000 rpm. Might be your problem right there. The difference between before and after i recurved my distributor was pretty significant.

[v8stang289]

Looking at an A9L timing curve, it looks like I would have to have 17* initial to get 34* at 3500... I may try to bump the timing to 14* or 16* and see what it does next time out. See if it picks up speed or not.

[brianj]

Honestly, once you get into the computer control on the 86 distributor, I'm not 100% on recurving it and adjusting it. I'm hoping someone with more fuel injection experience jumps in. I know what the motors tend to like, but not how you get there with an '86.

[v8stang289]

Honestly, once you get into the computer control on the 86 distributor, I'm not 100% on recurving it and adjusting it. I'm hoping someone with more fuel injection experience jumps in. I know what the motors tend to like, but not how you get there with an '86.

That's me at this point. Recurving a duraspark distributor is easy, this is my first real venture into modifying an EFI car.

[shadowracing]

U need to work on getting off their starting line with less tired spin that is killing some of your mph on their top end

[mmb617]

U need to work on getting off their starting line with less tired spin that is killing some of your mph on their top end

I disagree. While tire spin will definitely hurt your ET, a certain amount of spin will usually raise the mph. At least I've always found that to be the case.

[FUKAZ28]

Timing is my vote, you need to Google how to read spark plugs. It will give you the best reading on where the timing needs to be. Every engine is different. The plugs will tell you what it needs.

[brianj]

I disagree. While tire spin will definitely hurt your ET, a certain amount of spin will usually raise the mph. At least I've always found that to be the case.

Yeah, even when i completely massacre my launch, my mph stays pretty consistent, or even goes up a mph or two. More time to accelerate means higher speed.

[srad2drag]

Get your 60 foot down to 1.9-2.0 on hard radials and use the other suggestion as stated earlier.

[BigWillie]

Try locking the timing out at 34-36 degrees with the spout out at the track. That always picks up power and MPH at the track with EEC computers. What are your shift points? By crossing in 3rd at 5800 sounds like your over revving it on the 1-2,2-3 shift. Plus that stock mass air meter is killing airflow,its not allowing your engine to receive the air it needs to make HP.

[v8stang289]

Try locking the timing out at 34-36 degrees with the spout out at the track. That always picks up power and MPH at the track with EEC computers. What are your shift points? By crossing in 3rd at 5800 sounds like your over revving it on the 1-2,2-3 shift. Plus that stock mass air meter is killing airflow,its not allowing your engine to receive the air it needs to make HP.

I don't know if it would crank with the timing locked that high haha. Just curious, why does my 3rd gear rpm make you think I'm over revving in the 1-2 and 2-3 shifts? I'm shifting at ~5500-5600 in those gears, and just holding in 3rd because I would be shifting into 4th so close to the stripe. If it ever stops raining. I'm going to bump the timing up a little, and head to the track.

[BigWillie]

Lol....it will start,don't worry. Done this to a many 5.0's back in the 90's drag racing. I've just never seen a 3.73 geared T-5 car cross the stripe in third gear unless it was turning high RPM. My buddy has a 85 GT with exact mods as yours except his is a carb and with a 2.95 T5 and 3.73's shifting at 5500, he crosses in 4th at 5000. Here's a vid of him running 13.90's@100mph on heavy chrome 17in Cobra R's. His 60 ft times were 2.20-30 and he was shifting in 4th right past the 1/8.

[v8stang289]

Yeah, I would have to shift into 4th if I was getting close to 100, but the way it was going since I wasn't to 6k yet I felt I'd be better to let it pull through 3rd. I really expected around 100mph so I'm a bit disappointed at the performance right now. I'm just wondering what the root cause is. Maybe a combo of small maf and low timing. Maybe I need to try and clock the maf since I have a fenderwell intake. Not sure. If the weather cooperates I hope to run it again this thursday night with the higher timing. Then I guess I'll go from there. Thanks again for the input.

Here are links to the 2 runs

https://www.youtube.com/watch?v=OeUFgqs84T0

https://www.youtube.com/watch?v=RLrU...ature=youtu.be

[BigWillie]

Experiment with shift points, the engine may want lower or higher RPM. Keep raising timing until your trap MPH falls slightly. The locked out timing method truly works. Plus a 5lb bag of ice on that upper intake for 30-45min. will gain some power and torque. Remove or loosen that front sway bar for more weight transfer and pump the front tires to 45psi for less rolling resistance. These are all old school tricks that really work for lower ET.