Dyno'd my 5.0 w/ interesting results

so i took my 88 lx 5 spd. 5.0 to get dyno'd for my quarter mile time and i found out some weird stuff. it is a stock mustang w/ 140k mi. w/ no mufflers/side pipes, underdrive crank, B&M short shifter, and cobra clutch. i wasnt expecting any crazy times, but i was hoping for 14 flat. my instructor did 2 launches on the dyno from a dead stop, he dropped the clutch @2500 rpm and floored it w/o powershifting and it ran a 19. 1st and 2nd gear dominated and 4th was great. but 3rd totally sucked ass. 1st and 2nd gears were high rpm and went by fast, but when he put it in 3rd, it sounded kinda like he put it in 4th, and he said that 3rd gear had extremely low power compared the others. they did a second launch powershifting, dropping the clutch @3000 and smoking the tires through all of 1st and like half of 2nd. the car shook as he floored it and shifted hauling ass. then when it reached 3rd it dogged and then picked back up in 4th. it ran an 18. when i bought the car it came w/ a 4 pt. roll cage, B&M shifter, clutch, dumps, and it had holes drilled where a tach pod would go on the dash. so obviously it was used somewhat for racing. my instructor asked if the car had nitrous installed, and i told him that i didnt know. so he said that the probable cause of this would be the computer had been modified and had a chip installed retarding timing in 3rd to prepare for nitrous. this makes sense, plus it is kinda obvious by seeing some duct tape on the computer. he also said that it pulls hard for stock and that he could probably get it into high 13s w/ a new 2nd gear synchro and a chip replacement. i then took the computer out and opened it up looking for some sort of aftermarket parts. i have it apart right now, but dont see anthing that looks aftermarket. has anybody ever heard of this? does anybody know where an aftermarket chip would go inside of the computer???? any pics or diagrams??? any help would ge great. thanks!
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he shifted at 6000 everytime, and i think it does it all the time, but i just never noticed it cuz i just got it not too long ago and i dont drive it too much. plus, it has more power than my old car so im not used to the difference yet. my teacher said that the computers shouldnt be able to be flashed. he sad that the aftermarket chip is what is flashed. and he has a 10 sec. mustang so he kinda know his stuff. but i dont so thats why i need ur advice.
The nitrous reasoning behind computer changes is total BS. Former 10sec Mustang or not, your instructor sounds like he's seen F&F one too many times.

Find a stock SD1 computer (if it's a stock '88 non-mass air car) and put it in. Those things are dirt cheap since everyone is going to MAF.
Speeds8erM-1 said:
I dont put much faith into those dynos that let you run track times on them, wtf is the point. He was shifting at 6000? WTF, thats alot of the problem right there, the car is DONE at around 5000-5200 with the stock heads, cam and intake.


Also no mufflers? You say sidepipes i guess meaning it's a straight pipe right off the header or h-pipe running out the side? If so put some damn mufflers on it that'll hurt you also. He has a 10sec. stang what in the 1/8 he sounds like an idiot.
If there is an aftermarket chip then it would be in the rear of the computer and accessible from the outside. They're pretty obvious. If the car is speed density, then I'd lean more towards there being a problem with the MAP sensor or the vac system. A compression and leak down test along with an injector balance test might help you to shed some light onto what's going on.

Don't foget to pull codes. An ACT sensor that's out of range can also wreak havoc on SD during various load and power settings. Even if you don't get a code for ACT, make sure you check it out and see what it's up to along with your TPS.
This entire situation doesnt make much sense...there are too many f'ed up things that this instructor of yours is doing. for one why is he shifting the car at 6000 rpm even on the stock guages thats well into the RED. Like someone also mentioned before a stock stang with 3.08's will not even get out of 3rd by the 1/4 mile. The only possible explaination i have beside the guy being a total idiot is that he was timing how long it took him to get to the end of fourth...19 seconds, which still doesnt really make sense. Also he said high 13's were possible with a new 2nd gear synchro....WTF, i dont think so...like a second gear synchro has anything to do with ET's. i would find another dyno guy and i would never let a dude powershift your car at 6000 rpm man...bad idea
one more thing, what is my car's weight. it is stock 88 5.0 stick, w/ ac removed, no passenger seat and no back seats and spare removed, he typed in 3700 in the computer. the car pulled way too hard in first, second, and fourth to run an 18
Its a dyno, not a race track so take that for what it is. If you really want to know hit the track, and get on the scales. My guess was its his fault...

Your cars NOT 3700lbs. Mine with me in it is 3200 and about 170!I dont run the spare or jack, but have leather seats and such!
Put some mufflers on that thing and shift it @5000rpm. I ran [email protected] stock with 2.73's in a 5speed 87GT shifting @5000 rpms and running through the line @5200 in 3rd gear. Holy crap.....most H/C/I cars barely shift @6000 rpms. If your instructor is promoting the no mufflers then he is wrong big time and I have a muffler dyno shootout to prove it with no mufflers as the baseline.