well to add something that might be useful I've been tuning my car for the past week with HPT and my Innovate wideband, and the results have been pretty impressive.

Details:
2002 base model cavalier w/ 2004 ecotec 2.2 DOHC engine & 5 speed

mods:
intake
SMS 69mm tbody
tsudo 4:2:1 header
3" catless exhaust
3" resonator
3" magnaflow muffler
Fidanza flywheel
SPEC stage 3 clutch
stock injectors

using HPT I did several things outright: I raised my rev limiter to 7200 rpm (for 7k shifts), I also altered fan settings and other tidbits so the car runs more stable and predictable on the street and at the track as far as the temperature goes.

After hooking up my wideband, I hid HPT in the center console and have the USB cable ready to plug into the laptop whenever I need it, the OBD2 plug is hidden under the storage bin on the front of the center console, and can be pulled out and plugged in easily.

after a few baseline runs, I found my air/fuel ratio to be 14.0:1 under WOT. Unacceptable. Using the shifted histograms that he posted in his sticky and using the method he walks you thru I started VE tuning my car. I set my desired air/fuel ratio to 13.0:1 that way I could get a happy medium and once I richened it up too far, I could back off to my previous setting and stick with whatever air/fuel ratio that was.

the first few generations of changes made a world of difference. the car wouldn't drop off as much anymore, and just had more power no matter where the gas pedal was.

Unfortunately, after logging my injector duty cycle, I found out that stock injectors are WAY too small. I was seeing a peak of 102% duty cycle. I have pigtails for my 440cc injectors coming in soon, which will give me plenty of headroom to finish up my tuning. HPT keeps telling me to make changes, but when I make them, the results are still the same (pig ass rich up top) which leads me to believe that after a certain point, the injectors don't behave the way they're supposed to (probably 90-95% duty cycle) and can't recover in time to shut off the fuel fully.

Power definetly would not drop off as much after adding more fuel. I messed with advancing timing 2* up top as well, and that had a similar effect. I don't think advancing the ignition too far really helps that much unless you're spinning higher RPMs than 7000-7200.

Until I get larger injectors I'm at a stand still for now. I've also just installed LZM triflow cams which makes the car big time top end happy.

The car pulls decent in the midrange, but the party doesn't REALLY start until 5k, and it pulls hard all the way to 7k.


so my VE tables need to be retuned, but I'm waiting until I get my larger injectors in. I'll be posting pictures and explanation about my cam swap in the performance forum, and how to use the GM cam tool (made the job 1000times easier).

also, look for track videos of the new and improved n/a skwirl soon. After this winter, I highly doubt I'm going to still be n/a. One last hurrah in group A before moving on.

there will be pictures in this thread soon on my HPT mounting. I think you guys will like it...
Sleeper style FTW

in regards to your injectors I believe at a certai point (not sure where that point is), the injectors stay open at all times, so that could be why your getting soo much fuel.



FU Tuning

I don't doubt it

I'm seeing around peaks of 12.0:1 up top which is just way too much fuel n/a

once I get the 440s in (too large I know, but these are the injectors I was going to save until I boosted the car but since i need larger oens might as well upgrade now) I should get my control over the injectors back.

keep us posted!

Nate



Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft

Great informative post!


What A/F ratio are you shooting for? 13.0:1

I see your going for all top end in that puppy. Man, if you can get a good launch on a nice cool day. You should be able to lay down some really nice times.

Good luck with your last hurrah! Thats exactly what I'm doing too. I thankfully hit my goal (in sig) before I throw on my turbo. I'm still not sure if I want to do the gm reflash or go with HP Tuners. I have the map sensor for the reflash, but I heard they won't even do it if they find out I have a turbo instead of a supercharger. That is GAY!

Anyways, good luck! It must be nice to rev to 7000rpm! have fun with it.

PS: Better watch out skwirl. Small game season opened yesterday! lol



2004 Cavalier
13.2@105........
Mods...
BFG Drag Radials
Saab Turbo kit
2.5 exhaust, w/cutout
Spec Stage 2+ Clutch

lol well i just put cams in and the car is a whole new animal I def need the injectors in order to get the proper air/fuel ratio since mine suck


I'd like to hit a 14.7 or so but I just can't get out of the hole and don't have enough top end punch to pull thru. the car is definetly all pull uptop now, midrange fell a little but thats ok.

over the winter the car is getting some major engine upgrades so next year its goin to be a whole new arena