Ok so i went to the track last night for the first time. First time driving and with my motor setup.

my best run is 14.8 @ 92.22. I had some launch issues cause im new at it but i was getter better. 60ft is 2.135.

My car: 86 iroc, t5, 305 with: 113 alum heads, lunati cam 60101 ( 213in 219 ex @.50 112*), TPI (stock 86 prom), The motor has 2500 miles on it. tpi was cleaned inside an out before installing. I was also running street tires (cooper cobras), axel ratio is 3.27 posi. 3400lbs, heddman headers, magnaflow hi-flow cat and 3in cat-back.

I used one of those hp estimators online from the quarter mile time, and it came back with 206 at the flywheel. Now, i know im new to drag racing and all but there is no way my car only has 200 hp at the flywheel when in stock form they have 230ish. i know those estimators are not that accurate but i was figuring/hoping for a little more power.

known gliches: it runs rich but doesnt smell, only gets 11mpg on the street with gentle driving (no racing). it surges in light throttle on occasion and when slowing down it almost stalls. let me explain. lets say im slowing down to a stop light, id go into 2nd gear as i got slow enough and let the car idle down in gear as im slowing down. when the rpms get to 1400 it surges (jerks the car forward and backward like lack of fuel under acceleration) now if i slow down with the car in neutral it will do the same thing, as im slowing down the rpms will drop to 600 or even 400 and almost stall but catch itself and idle at 1k or 900rpm.

So any insights or ideas? just looking for a place to start looking. every sensor is brand new with 2000 miles on them. tune up has 3k on it (cap, rotor, plugs, wires).

 

230 hp stock is under ideal conditions: 60 or 70 degrees F, whichever they used back in those days for SAE correction, 29.?? baro, no wind, et cetera.
Now, even with all your speed parts, it is possible for you to be making less power than stock, especially if you're using all of them with a stock tune. The '86 TPI only came with 195 hp and an automatic, and the spark advance curve is all wrong for what you now have, even if you did bump the initial.
Your poor engine behavior is mostly from trying to use that cam with that tune. Go get a dyno tune. Don't buy one more thing until you dial in what you already have.

 

ok yeah i figured it was the stock chip on a modified motor. the only problem with dyno tune is no one around me does it for tpi. its 96 and up around here. :/ im probably going to buy the prom burning equipment and do it myself. I want to learn and i can do it just needs some trial and error.

 

any other comments?


one more thing, now when it gets hot the idle kinda floats from 500-1000rpms almost stalling. driving its fine except it stumbles while its hot now. Im thinking its the coil cause my tach jumps at low rpms.

 

Nascar,
I seem to have a similar problem, have you had any luck?

 

Did you get those heads milled before installing them?

 

have not found a solution to the stalling/stumble while slowing down. its annoying cause it happens almost every time i stop.

I need to get a data logging cable or something.


I did not get the heads milled before installing them. They were not even ran on the motor as the valves were not discolored or anything, there wasnt even oil on the heads. As far as the compression it is fine because the old heads had the same CC's and the pistons are dome'd. I dont have high compression, i would say about 9ish.

 

Edit: I actually bumped up my fuel pressure a little and it took away SOME not all of the light throttle stumble but its harder to start when its cold.

 

Your combo would only benefit from milling the heads about 0.030". Until then, you should be good with regular unleaded. That'll let you pull some spark advance, ( lower octane burns faster ) which means less negative torque at the end of the compression stroke.

 

ok no doubt it wouldnt, i would have loved to put better heads on to begin with....actually i would have liked to have a 350 but money is/was an option.


so im pretty sure all the issues are computer related and i need to A. find someone local, not 8 hours away, to tune it OR B. get my own tuning equip and figure it out on my own.

 

you wont know the power til you dyno it.

not about the power its about how it performs

 

I agree. Right now its really torquey which is good. On colder nights it roasts the tires almost through second where as during the day it wont. So there is def a fuel issue somewhere.


Unfortunately this problem is on the back burner because its getting painted, well in process of getting painted.