Pontiac G8 GT (6.0)

[Boost]

I would like to find out some more about this engine. I will be tuning it in the future, and the owner has a lot of questions about the heads, DOD, etc. Is this a vehicle that was a Holden also? Tuning tips for the E38 specific to the L76? Any weaknesses / things to watch out for with the DOD? Thanks a lot! Any interesting G8 info would be nice.

[swingtan]

Depending on what the customer wants.....

The motor is good and should get to the 260rwkw ( 350 hp ) mark with just a decent exhaust and a good tune ( manual ).
There is not too much that can go wrong as long as you follow the normal tuning process, pull timing, get the fueling correct, then work on timing again. The DOD gear is OK and but many choose to just disable it as the returns gained from tuning usually meet or exceed the gains from the DOD mode. You could alway try and improve the DOD performance as well, though I'm not sure if there is much room there.

Heads: Flow tons on the inlet, less on the exhaust thanks to the valve sizes. No real need to do heads unless you're looking at big camshafts, stroker or maybe FI. A shave to bring up compression would be nice though.

DOD lifters: can get a little noisy at times as well. If there is going to be a lot of work done, then it may be an idea to remove the DOD lifters altogether. It's not always required though as mine have been in place with a smaller lift cam and are fine, I don't have working DOD mode though so the lifters never unlock. If you were going to play with the heads, I'd remove them while the heads are off.

Given that you're mentioning DOD, I'm assuming that it's an auto, so to get the most out of it you'll need to tune both the ECM and TCM. If it's your first GenIV - E38 /T43, you will have a bit to learn........


Simon

[Boost]

Thanks a lot Simon !!! :)

[ls327]

L76's with DOD are very sensitive when adding timing // DOD' lifters will not support 6500 RPM's // i got rid of my noisy DOD lifters , it all comes down 2 the goals of the owner..

[Boost]

That makes a lot of sense, thanks! He is thinking about doing away with the DOD and / or modding heads. So basically this block is very similar to LS2?

[swingtan]

Depending on the fuel being used, the L76 can take a fair amount of timing in bolt on form. Normally a few more degrees than the LS1 could take in the same configuration. The huge inlet valve on the square port heads gives a big increase in over all airflow and as many would know, an increase in airflow can allow for an increase in advance. Setting the Knock calibrations is a must though and this goes for all Gen IV motors. The std. calibrations are over sensitive to allow the stock tunes to run excessive timing in an attempt to give good emissions and economy figures. If you get the fueling right, the timing will be pretty easy to dial in.

As for DOD lifters and high revs..... I have my limiter set to 6400 and don't go there that often. The makeup of the lifter with the locking pin setup and the additional weight simply rules them out for high RPM work.

With no machining, (IE. just a cam change and bolt on bits ) the limit seems to be around the 350KW (470HP) mark NA. I wouldn't be revving it to 7000 with the stock rod bolts though, not unless you intended to change blocks.

Simon.