Just as a point of reference for those considering a TBI build and are required to pass an emmision test. Here in NW Indiana we are required to pass an IM240 (IM93) dynamometer type test. Visual inspection consist only of verifying cat on car provided the sniffer test passes. A little over a year ago, when the build was just completed and tuned it passed the test but HC were very high (I think .76 with .80 allowed). NOx and CO readings were very low. It was just re-tested and passed with room to spare. Between the 2 test very little changes were made to the tune for idle and part throttle (most changes were for WOT). However, timing was advance about another 2 degrees. I did add 2 bottle of Iso-Heet to about 3/4 tank of fuel just prior to the test. This time HC (about .4 with .8 allowed) were down substancially with only a very small increase in NOx and CO but still very low compared to the limits. Here is some data on the build for those considering something similar who need to pass an emmission test: - Rebuilt 355 Vortec Long Block (roller cam, vortec heads) - Hypereutectic flat top pistons (10.3:1 compression ratio) - Comp Cams Extreme Energy Camshaft P/N 08-502-8 • Gross Valve Lift Intake – 0.495 Exhaust – 0.503 • Duration at 0.006 Tappet Lift Intake – 269 Exhaust – 276 • Duration at 0.05 Intake – 218 Exhaust – 224 • Lobe Separation - 112 - Crane Valve Spring Retainer Kit – P/N 10309-1 - Pacesetter Mid Tube Headers and Y Pipe – P/N 72C1336 - GM 2" TBI with 80lb injectors @ 16psi - GM TBI to Quadrajet Adaptor Spacer – 1.75 inch - P/N 10045799 - GM Vortec aluminum intake manifold P/N 12496820 - Open element air filter - Magnaflow 3” Catalytic Converter - MPE-93441 - 93-97 Chevrolet Camaro MagnaFlow Exhaust 15620 - Champion Spark Plugs RS12YC - Jeg’s 8.0 mm Silicon Spark Plug Wires - AIR system pump connected and operating - EGR valve mounted but disabled in chip Dyno2000 say this combo should make about 400 hp. Al

Alvan-

What fuel pump are you using to get the 16psi, are you able to get that with the stock TBI pump or did you swap in a new one?

Thanks,

Paul T.

That is a great setup!!

What are you using to tune this thing?

Why??? I'd throw those Chrysler PoS's as far as I could and get some Delcos or NGKs. But I guess whatever works for ya.

Great setup. Congrats. Next thing after your emissions checkup... DYNO results!

good job, dude. After sweating it, I went in with my truck (350HO, 90pph @ 15 psi, headers, blah blah blah) and passed too. Feels good!!! I can have my cake and eat it too! I love beating the system.
It's all about the tune

Is anybody willing to share their secrets for their "Emissions tune"? What changes were made to your tune as far as timing and such. I understand if you don't want to post it as there are smog nazis everywhere anymore but would appreciate a PM. I'm particularly interested in if you made any EGR changes to your bins.

As far as the fuel pump goes. I am not sure what pump is in the tank. I have not changed it, but I have no idea if it is stock or not. I can only say at this point it has not presented a problem with supplying this engine as others have reported.

All tuning has been done using WinALDL, TunerPro, and a simple DVM. AE is the biggest problem to get consistent under all conditions. WOT (PE) was not a major issue.

I have always had good luck with Champion plugs, but yes you guessed it I have always been a Mopar guy.

As far a secrets of tuning for smog test.... I really have none. The smog test was run with the same tune which was done based on driveability and performance. Yes, this set up takes a lot of low end timing and I was concerned about that but it did not seem to be a problem. This engine seem to want either a lot of timing at low rpms or lots of fuel to run. I figured more timing was better. The only thing done for the smog test was adding the iso-achohol to the gas, thinking it might help with the HC emissions
As I said previously, all the egr stuff is on the engine, but it is disable in the chip since I thought the cam would provide more than enough natural egr and since NOx readings were so low I guess that is correct.

Still looking for a place local with a dyno and maybe will get a chance to change the gears over the winter and then some track time next summer.

Al

Awsome results Alvan, this is a perfect example of what can be done with proper tuning and TBI. Without a doubt you have a bottom 13's to high 12's car depending on gearing and traction. What kind of mileage are you getting out of this combo?

Have not checked mileage since it is not a daily driver and has not been a priority. With using it strictly for local cruising I do not believe mileage is very good. It also runs rich until it warms up and enters closed loop. Still need to address this issue.