I have a 91 firebird, with an L03. Last year, bone stock, at Bristol(1475ft. asl) the car ran a best of 16.80, at 80.70. This year, I added a complete exhaust(1-5/8" headers, by hooker, and a 3" y-pipe, 3" flowmaster after cat exhaust with a 3" catco high flow catalytic converter) and a smog pump delete, a crane cams fireball ignition and coil, and an accell ignition module, and new plug wires(8 mm mallory). The car still needs plugs, and a cap and rotor, and Im getting a fault code(32 I think, egr, map, or something else). Plus I added rims and tires. Not that they matter, but the fronts are 165s, on a 15 X 4" rim, and the rear is a 275/50, on a 15 X 8.5" rim. They are centerline convo pros. The car has an auto, and 2.73 gears. Also, I still have the stock aircleaner(although I have a K&N in the basement, just waiting to make a cold air out of it).

Last night, with temps in the 70s, it ran a best of 16.36 at 85.34. The engine temps were hovering around 190-200 for the run. But thats all I could get. Is this about right? Or have I messed something up. Bristol is notorious for slow times, and some have reported 2 tenths faster at other tracks. But I was hoping for a 16.1. Next itll get 1.6 rockers, a tune up, cold air, and an egr, I guess. Can I expect a 15.9-15.7 with this? Sorry this is so long. I want to get all the info out I can.

 

gears....

 

1.6 rockers will help a little as the cam in the L03 is tiny. Really going fromthe first number to what e running now you picked up 5 mph and half a second which is pretty good for basically just a full exhaust system. The heads are going to hold you back for now but there is still more in them before you decide to upgrade. Also if i remember correctly if the CEL is on you will not get a full advance curve out of the computer, which could be holding you back as well. 3.42 gears would help as well, but i wouldn't go any more than that. Definetely do the cold air induction as well. Hope this helps some, I know that there is a guy on here with a TBI car that can flat out run. Overall though, not bad times. With what you are planning to do next I don't see why mid 15's aren't possible.

 

i think you should fix the codes first...your faulty egr might be robbing you of a lot of power.

 

Gears and a rearend build are next year. And Im starting this weekend on the codes and tune. Im going 3.42s, or 3.73s, and 28 spline axles, with a no-slip posi(like a locker, but easier on the rearend). Also maybe some lift bars, and SFCs. Im gonna try to get into chip burning over this year, and the winter, and make the TBI mods listed in the forums too. Maybe an intake and a fuel pump, or cam( I want to do this last), and if I can squeeze it in a 50 shot of N20. We will have to see. Im shooting for high 13s, low 14s without spray.

 

If ur wanting to get there without spray, it's time to dive in and put a cam in it!! Nothing real big though, and sick to the 3.42 gears, the TBI setup is not built for running up in the upper RPM range, keep it in the 2K-5K range and you should be ok.

 

Its not hard to make the TBI engine make power at 6-6.5K though!

 

I figured that he should plan to keep it inthe lower rpm range though unless he is planning on doing some head work, or replacement.

 

I have a near stock L03 with 289,000 miles that pulls hard all the way to its 5,600 RPM WOT shift points. Basically it has Ultimate TBI mods, Chip tuning, 1.6:1 roller rockers, 4* cam retard, stock cam, stock heads, 1" open center TBI spacer, needs exhaust (factory pellet cat still).

https://www.thirdgen.org/forums/tbi/...i-project.html

 

Im trying to decide what I need next, besides a rearend, or gears. Thats a big project for next year. Im getting rocker arms for fathers day, and will be starting the TBI mods as soon as possible. Ill also fix my codes, and give it a good tune up. After all that, and a cold air kit, Im shooting for 15s. Then Im about done for this year. Ill spend the winter gathering chip burning equipment/information, and then put a custom chip in it for next year.

I listed next years hopeful mods, and am wanting to go 14s at least, but hope to get a N20 kit, to go 13s, maybe. We will see. One trip to the emergency room, or something can change all that, quick. Especially with three kids.

Does it seem like Im headed in the right direction, to obtain my goals? Ive been wearing out the search feature, especially in the tbi section, to find everyone elses successes, and failures.