fieroguru

iTrader: (1)

I am tuning the LS4 w/ LS2 intake/fuel rail/injector/TB/MAF in my Fiero and wanted to swap back to the the stock LS4 injectors to dial in the MAF upgrade. So with the ebay injector spacers (about $50) and some 5/8" tall spacers (or two 3/8" nuts stacked) the LS4 fuel rail and LS4 injectors bolted into place on the LS2 intake w/o issue.





Once you ditch DoD, the LS2 intake/TB/MAF swap is pretty much a bolt together upgrade. Sure the LS6 intake is better, but simple and lower cost have their merits too.

Haulin_Ls4_GxP

iTrader: (1)

Looks bad ***. Last I saw you were modding the water pump manifold to make it work with your setup. It's come a long ways looks good man.

91parkave

iTrader: (4)

Lookin good man why did you have to go back to the ls4 injectors ? Did copying the ls2 mad and injector tables over not work well enough for your base tune?

fieroguru

iTrader: (1)

It was about removing variables to help dial in the tune quicker. This swap had everything done at once which makes it difficult to determine if the fuel trims are a MAF calibration issue or a fuel injector issue. Taking the fuel injectors out of the mix let me focus on the MAF. If the weather cooperates I hope to have the MAF part throttle tuning done, the LS2 injectors/fuel rail reinstalled and a couple of WOT blasts.

List of engine mods:
2007 LS4 w18K miles and E67 ecm
LS2 85mm Maf, 90mm TB, Intake, Fuel rail, fuel injectors and 4" CAI
224/232 New Era DoD camshaft, pushrods and springs
LS7 exhaust manifolds into a single 3" in dual 2.5 out magnaflow muffler.
G6 F40 6 speed transmission, 12lb aluminum flywheel and a 10" spec stage 4+ clutch.

91parkave

iTrader: (4)

Gotcha well happy tuning love the info you provided for the community and BTW are you familiar with bluecats program? It will help you nail your virtual ve in a lot faster as well

fieroguru

iTrader: (1)

Thanks!
Yes, I already have the latest version of bluecats program. It is pretty sweet!

GXP25

iTrader: (3)

fieroguru: What about the LS4 fuel rail with LS2 injectors on an LS2 intake manifold (plus the LS2 throttle body and MAF).

Is the LS4 fuel rail just a fuel rail that's "shaped" the way it is for the FWD application? Or is its tubing "smaller" than other LS engines and therefore would be better off changed out?

I'd be looking to keep DoD and modify the LS2 intake yet keep the LS4 fuel rail (save money and time) and swap out the injectors and TB and MAF.

fieroguru

iTrader: (1)

The LS2 injectors are longer and end up the same length as the LS4 injectors with the injector spacers, so once you add the 5/8" fuel rail spacers you can run either set of injectors, but I suspect with my upgrades the LS4 ones are going to be maxed out, which is why I will be switching back to the LS2 injectors.

If you notice, GM has all the fuel lines coming off the engine to the side of the car. Since the LS4 sits in there sideways, that means the fuel lines come in from the back of the engine or 90 degrees from a typical LS(x) engine. The tubes on the LS4 are all the same diameter as the LS2 rail, so I don't think there is a performance improvement/limitation between the two, just personal preference on how you want the fuel line to be routed.

DavidGXP

iTrader: (14)

Looking good, and thanks for sharing!

GXP25

iTrader: (3)

Did we confirm or disprove that the LS2 throttle body requires an 07+ LS4 (E67 ECM)?

Can the throttle body be used with an E40 ECM (05-06 LS4)?

91parkave

iTrader: (4)

Since ls2 use e40 pcm then it should work