well here is the problem, last year i took the iroc to the track and ran a best of 15.01 bone stock. Over the winter i did a few things such as headers, y pipe, ported intake, plenum, runners, crane powermax 2040 cam and lifters, shift kit, new tires... anyways i took it to the track last week and could only get a best of 15.09. I know something isnt right here. At low rpms the car kind of bogs a little until i hit about 2 or 2500 rpms. I havent had any tuning done just what i mentioned above. I would think i could at least run a tenth of a difference better with the mods i did but i guess not. Will tuning make a big difference, do i need more fuel pressure? what the heck is the problem here? i need some help! thanks

 

Did just a few little things? Headers, cam, ported intake and runners, sh*t, why didn't you just say your virtually replaced the motor?

Yeah, tuning is "probably" required. Have you done any data logging to see how it's running? My guess is it's STARVED for fuel..... maybe knocking as well.

Can you say "custom prom time"?

Don't want to appear a smart*ss, but with an electronic computer controlled injection system, anything that ups the power much will require prom burning. One way to determine that is think about it this way: If I did all those changes on a carb motor, would I need a bigger carb or bigger jets to power it? If so, I probably need a new prom.

My suggestion is to datalog it. Increasing the fuel pressure MIGHT take care of it for you. But w/o datalogging it you can't tell if you're at the right level when you do change it.

 

tuning woudl optimize your setup but you shouldnt need that much, your stock calibration should be really close, 85 did get teh better cam ya know. anyway i can say from experience that you should have run better than that. 15.0 is dang good for a stock one, but i see you didnt gain anything. first off what were the weather conditions the first time you ran versus the runs you made this year? did you just port the stock plenum runners and base or are they aftermarket? as long as you are sure everything is adjusted correctly like ignition timing and throttle position sensor, i would say either the weather screwed you over or you have another issue that we dont know of yet. what kind of fuel mileage do you get?

for reference i ran a 14.8 @93mph with an LPE 214/224 cam, headers and ported plenum and base. you can see my sig to see what it runs now with the stock chip still in place. needless to say you should be able to scrape up at least a high 14.

 

go check out craig moates site , get your self a burn 1 and a few chips , start burning away

i recently done up the 86 305 tpi with 20 000 original miles

i put the comp cam x treme energy 212-218 449-456 112 lsa, ported the stock heads with bigger 1.94 intake valves , new comp springs ,retainers valves, 3 angle valve job , 3.42 gears ,still using the hypercrap chip with my set up but the idle is bad and the car is starving for fuel

my set up should have me in the low 14's , but than again you need to tune the chip up to get there

 

well last year was in the fall when i ran so it was colder compared to this year it was hot a muggy. i only ported the stock planum, runners, and base so i prolly didnt gain much there. Im sure the timing and tps are correctly adjusted, ive checked it many times trying to figure out what is wrong. I know the weather wasnt the greatest for running but i didnt think it would make me run worse then i did stock. Anybody else know what could be wrong here?

 

Just for reference, he figured out most of his problem: cracked distributor cap. He hasn't had a computer for a couple of weeks to reply, but I talked to him a few days ago and he said you could see sparks flying from the top of the cap. I kept telling him it was probably something simple

I've been working on getting a '165 ECM to swap in so we can do some data logging and see how it's running otherwise. I'll hopefully be getting some burning equipment sometime soon so we can try a different tune also, so we'll see how it runs then.