Capabilities of TT on 10:1 pistons

[DrGonzo]

I am wondering what kind of power/setup people are using on 10:1 pistons?

I need input and thoughts as to what limits the 10:1 pistons. Is it just the higher compression and not being able to run high amounts of boost. Are there other areas I am missing?

Right now I have the car set up on a conservative tune at 6psi until I can figure out why the damn logger won't connect.

My current list of mods are below:

Walbro Hotwired
All -6an fuel lines + -6an fuel loop
Stock injectors but have a set of 450's on the way just in case
Fuel lab FPR set to 50psi
stock turbos
Stock SMIC
Full SS Ebay exhaust gutted cats
Vac reduction
Pre turbo intake pipes
SAFC
AEM WB
N/A bottom end with 10:1 pistons and cast crank
Also going to go Blowthough with MAFT/GM 3.0 MAF/ Dejon pipes as I don't want to deal with boost leaks. Plus I already have all of the parts!

What would I need to do to be able to run say 12-15 psi boost? Meth/Water/Alk injection?

I'm not looking to upgrade turbo's just yet. I want to see what I can pull out of the 9b's and 10:1 bottom end before I upgrade. I want to do this without blowing up the engine.

I also have a knock light on the way so I can always watch for Knock without needing a logger hooked up.

What's everyones thoughts???

[fullracegt]

e85 with a fmic would help alot but your kinda limited by your internals,my opinion but im no expert lol.

[Markingtime]

That light knock you are hearing is probably detonation. It will turn your 10:1 pistons into 0:1 pistons very fast. You should back way off on your boost before you have to start over. That is the reason boosted engines are rarely more than 8:1. I have heard of 9:1 with a good water/methanol injections system, but still at pretty low boost.

To go up to 10:1 you will need GDI (Gasoline Direct Injection) heads. There were some 6G72s and 74s with them. In GDI the fuel is injected directly into the combustion chamber close to TDC so there is no fuel to detonate until it is time to ignite it anyway. There is a good description of Mitsubishi's GDI technology, with video, about half way down this article: Browser Warning . It also references Mitsubishi's 10:1 1.8L GDI Turbo here: Browser Warning . I couldn't find how much boost is being run, but probably 10psi or less. The new Nissan Juke comes with a 9.5:1 1.6L GDI turbo maxing out at 12psi of boost, although the waste gate starts opening up at 9psi on its tiny turbo.

Good luck on your project. I hope detonation has not already caused any damage.

[DrGonzo]

Trying to stick with the 93 octane I have available around me. I don't want to have to deal with special fuels, just what the local gas station has to offer.

I am debating going FMIC, Either and Oohnoo dual of a CX racing single FMIC

[BaadVR4]

The problem is peak cylinder pressure and the resultant cylinder temps. With the 10:1 CR, you won't be able to run more than about 10 psi boost, even with methanol injection and a good FMIC set up. And that will severely limit HP. With an 8:1 (or even 8.5:1) CR you can run 30+ psi boost (as long as you have the supporting mods needed). At a "rule of thumb" of 15 HP per pound of boost, your HP potential with the lower CR is right at 300 HP more than the 10:1 set up.

One other small item: are you running an NA block? If you are, you should know the internals are not the same as the TT. The later TT blocks are 4 bolt mains, the cranks are forged, with nitrided journals and the block has oil squirters that spray oil onto the bottom of the pistons for improved piston cooling. All these things are important when you want to make more HP.

[BaadVR4]

Deleted as this was a duplicate post.

[DrGonzo]

That light knock you are hearing is probably detonation. It will turn your 10:1 pistons into 0:1 pistons very fast. You should back way off on your boost before you have to start over. That is the reason boosted engines are rarely more than 8:1. I have heard of 9:1 with a good water/methanol injections system, but still at pretty low boost.

To go up to 10:1 you will need GDI (Gasoline Direct Injection) heads. There were some 6G72s and 74s with them. In GDI the fuel is injected directly into the combustion chamber close to TDC so there is no fuel to detonate until it is time to ignite it anyway. There is a good description of Mitsubishi's GDI technology, with video, about half way down this article: Browser Warning . It also references Mitsubishi's 10:1 1.8L GDI Turbo here: Browser Warning . I couldn't find how much boost is being run, but probably 10psi or less. The new Nissan Juke comes with a 9.5:1 1.6L GDI turbo maxing out at 12psi of boost, although the waste gate starts opening up at 9psi on its tiny turbo.

Good luck on your project. I hope detonation has not already caused any damage.

I think you mis-read my post. I don't have any knock at this point and I am only running 6psi wastegate boost.

[DrGonzo]

The problem is peak cylinder pressure and the resultant cylinder temps. With the 10:1 CR, you won't be able to run more than about 10 psi boost, even with methanol injection and a good FMIC set up. And that will severely limit HP. With an 8:1 (or even 8.5:1) CR you can run 30+ psi boost (as long as you have the supporting mods needed). At a "rule of thumb" of 15 HP per pound of boost, your HP potential with the lower CR is right at 300 HP more than the 10:1 set up.

One other small item: are you running an NA block? If you are, you should know the internals are not the same as the TT. The later TT blocks are 4 bolt mains, the cranks are forged, with nitrided journals and the block has oil squirters that spray oil onto the bottom of the pistons for improved piston cooling. All these things are important when you want to make more HP.

Yes it is an N/A 2 bolt block. The N/A block and cast crank will hold for the HP range I am looking for. Cast cranks are good up to the 400hp range from the research I have done and the people I have talked to running FWD TT's/superchargers. me personally I wouldn't push the block and crank past the 380 mark. I'm only looking for about 350 tops.

The 350hp range should be possible? Correct????? or am I out of my mind...LOL

[Markingtime]

I think you mis-read my post. I don't have any knock at this point and I am only running 6psi wastegate boost.

LOL, you're right. I read Light Knock instead of the Knock Light you mentioned. However, detonation is still going to be something you are going to have to be very careful about with that CR.

[RL7]

May depend where you are now. If your putting 290 to the wheels at 6psi then 350 is probably realistic. If it's 200, then probably not. Knock light is a very good idea. I like high comp + fi for a daily driver because it isn't nearly as laggy as a normal turbo car. If your goal is 350hp a 10:1 car should be a lot more fun to drive than an 8:1 at the same hp. Less reliable and it will probably break sooner than the 8:1 would, but if you keep detonation at bay, you should be somewhat ok.

I too would like to know how high people have gone hp-wise with 10:1 though.