A little curiosity as to wtf

[IROCdan330]

Whats up all...car is having trouble...

Fasterthanyou and I were at atco last night, attempting to tune my car again...but beings my cig lighter is shorted we couldnt datalog, so Jon went by what he felt was going on.

For some reason, my car runs better on the stock 5.0 chip than on a 350 chip. Jon believes its a fuel delivery issue...I bought 24# SVO injectors for the vehicle, yet when Jon set the injector constant at 24, the car ran lean. Right now its at 20# and it has more power/better fuel economy. In the very near future I'm going to swap the stock fuel pump out for a walbro. Could the fuel pump be the only issue or is there something else I should look into. The car has no balls on the top end of its rpm range...and my damn transmission wont get out of 2nd gear by the trap because the governor is letting it rev too high (past 6 grand with a TPI engine).

My first run last night was a 15.8 @ 86 somethin (2.58 60' though). With the stock 5.0 chip, and a better launch (2.2) i ran a 15.0@89...which is close to my 305's best at 14.9@90. Today I ran with my school at atco, and ran a 15.9 on the first run and a 15.5 on the 2nd. both at 86. I gave up and came home after that.

Stuff in the powertrain are as follows:
350 crate engine, vortec heads, lt4 hotcam, scoggin dickey intake base with slp runners, 24# SVO injectors, holley AFPR, hooker headers...the trans was built by ziggy's...if i had a higher revving engine itd be great but yea.

Any help?

[Slow Z]

Convert to carb and go 12's without all the BS and money 8) ...sorry cant give ya any help when it comes to that high-tech fancysmancy EFI contraptions

[IROCdan330]

Originally Posted by Slow Z

Convert to carb and go 12's without all the BS and money Â*8) ...sorry cant give ya any help when it comes to that high-tech fancysmancy EFI contraptions

You know man, I'm really thinking about it at this point. Many people I talk to say the same thing, and you and i have very very similar engines if im not mistaken?

whats your best 12.2?

[Slow Z]

Originally Posted by IROCdan330

whats your best 12.2?

Not officially yet but its in there.... I've only run the car a few times it went 12.50's on motor with the carb right out of the box, conservative timing, and me not knowing how to drive it. Been in the 11.80's on a 100 shot spraying half-track. Theres a TON left in this car I just never have a chance to make it to the track and figure out what works. 12.20's on motor and 11.0's on a bigger shot I'll be happy.

[IROCdan330]

you have a pm.

[NJSPEEDER]

drop in a walbro 255lph and fix your cig lighter so everything can be data logged. your description sounds like teh stock fuel pump you have in there is just running out of steam

later
tim

[89 Trans Am WS6]

Dont go join the dark ages of carbs..


so much more can be done with efi..

Do like tim says and get your damn cig lighter fixed and get real datalogging..not guessing

[Pampered-Z]

I would do anything until you get some data logged and determine exactly what is going on. Why put in a FP without know if that is the problem? There are enough people running hotcams in 350 TPIs with the stock pump.

Where do you have your fuel pressure set? and what is it doing? Is it dropping low that you think is why it's going lean?

[NJSPEEDER]

Originally Posted by Pampered-Z

I would do anything until you get some data logged and determine exactly what is going on. Â*Why put in a FP without know if that is the problem? Â*There are enough people running hotcams in 350 TPIs with the stock pump.

Where do you have your fuel pressure set? Â*and what is it doing? Â*Is it dropping low that you think is why it's going lean?

i talked to dan on AIM and he said he can only get 44psi with the AFPR screw bottomed out, he is also still on a stock pump with a beefed up motor.
GM undersized the stock pumps in the thirdgens pretty bad, it isn't uncommon to see pressure bleed of with a stock engine, much less one with a healthy head and cam combo in it.

later
tim

[badzracing]

Change the governor to a "heavier" one as I told you before. And Tim tells me it's quite easy to do in your year car. That will help with the late shifts.

[IROCdan330]

update guys:

After a little diag, turns out my fuel pump wasn't cutting it. replaced the fuel pump a few days after this with a walbro 255, as well as having my valve lash reset (a few valves were too tight). i put it on the dyno so i could get some wideband information for Jon (Fasterthanyou), and it turns out this time around the a/f ratio was so far off (too rich) that it went off the scope...still put 226 down at the wheels for horsepower with a 20# injector constant in the comp, and too high of fuel pressure. i checked the pressure the next day, and instead of the AFPR being bottom out at 44psi, it was well over 50 psi this time. Hm...new fuel pump is doing good. I turned it down, drove it to Jon at his house...and we then spent all of Sunday tuning. My car hauls ass now, im very very pleased. Times will come soon.

With regards to my transmission...i replaced the governor with the stock one...the "too long" shift problem is handled...i just somewhat wish that the TC was still electronically controlled, as now if im not at WOT it will lock up at about 45 mph. not a huge deal...just takes a little longer to downshift when i choose to go WOT.

[badzracing]

Dan, I'm glad things are working out for you ( especially the tranny). In hindsight, you probably should have stuck with the electronic lock-up ( John can tune it I'm sure). The hydraulic lock-up is great for street-rod guys who don't want to have to go through the b.s. of having to buy a computer just for it, but you probably would have been alright sticking with the computer controls. Oh well, like you said it's not a big deal and I'm sure you still have no problem hauling pretty good ass.

[Slow Z]

...when you wanna put 326 down to the wheels lemme know....

[badzracing]

When you wanna put about 600 to the wheels...........................buy my engine ( or the whole truck).