Head gaskets for supercharged twin turbo

[IS400]

i am in the process of rebuilding my 92 LS400 engine for a swap into my IS300, i have my hands on an M90 supercharger and i plan to set the boost on it for right around 6psi, then i plan to twin turbo it with 2 TD04 turbos with internal wastegates and and i want them together to push 10lbs so 16 psi total, right now i have been looking at the lextreme .074" MLS gasket and was wondering since i want to keep my stock bottem end if i can stack a .051" MLS gasket on top of the .074" to lower my comp ratio even lower and run 2 intake manifold gaskets to keep it lined up, the reason behind this thought is i had a R1 i had turbod' and what i along with many others were running was 2 oem headgaskets to lower the comp. need some thoughts if this will work, i have a MAPecu2 from a previous project i plan to use instead of it being previous money wasted, and planed to run 600cc injectors, i am looking into E85 for fuel but it is scarce here in east tennessee only 1 to 2 stations have it so i unless more get it i will be on pump gas, and looking into John Reed (big supra guy) for tuning as he comes into town to tune quite often

 

[IS400]

and of course i am planning on using the race rod bearings and arp head studs

 

[cribbj]

What you're proposing is called Twin Charging, and there are some here who have experience with it, namely our own MacLiver type called Justen.

Good wastegate and bypass control is everything for this, because the ratios of compression are not additive as you indicated, but are multiplicative, ie 6 psi of boost from the supercharger + 10 psi of boost from the turbos does not equal 16 psi, but 20 psi. So boost pressure can go through the roof very quickly.....

Many of the photos have been lost, but I began a thread (and a project) for a twincharged Supra motor here: http://www.lextreme.com/forums/showthread.php?t=11453, which you might find useful.

 

[IS400]

thank a lot and i really appreicate it, my 2jzge is turbo as of now and i am fimilar with that but not superchargers nor the twin charging method, i appreicate you input as it is very much so helpful, i will look into the links and keep thinking on the subject further, do you have any input on the headgasket idea? and how much boost id be good for with a setup like that?

 

[JustenGT8]

Been there and this stuff is not for the feint hearted. At the hp levels you are looking at, it's not really worth all the effort for a 4 litre V8 which would deliver the same result with just a proper sized twinscrew or TT setup.

On a UZ twincharge only makes sense if it's a built engine that can take a heap of boost, as that is what you will end up with. and, you are chasing decent hp numbers with the equivalent sized bits.

For example. My 1st twincharge setup (which was still well thought out) 'only' made 500hp at the rear tyres....but it took 25psi to do it! On the exact same TT setup with no SC (an M90 in this case) it would make over 700whp at the same boost.

Mid range was awesome i have to say, but a good twinscrew would have delivered the same result and TT only was a better performer overall.

The new twincharge setup i am trying to get will need to use an M122 and a 1350hp single T aiming for 1000whp and still a streetable bottom end....which you wouldn't have with T only. This will require a smidge over 30psi of compound boost to achieve!

Save your head and your wallet and just use the TT's you have. They are small enough to give very good response and your top end will be better as well.

I'll duck back to my thread to explain why my twinscrew has killed the twincharge idea for now