2007_wichitaSCION

does anybody up the rev limiter or replace the valve springs to allow for higher revs or is there more then to it then that and i just dont know it? 6k sounds a little low for a stage two turbo setup running even on low boost right?

kikcaffine

6250

B_Real45

You'll need a standalone computer to raise your rev limiter.

It's also a good idea to upgrade your valve springs, retainers, and seats.

Our redline isn't astronomic but it's fine with a properly sized turbo. Keep the exhaust housing around .48 and get a larger exhaust wheel. The larger wheel will create more power than a standard exhaust wheel and the .48 AR housing will help spool the turbo better and keep the power band between 3-6k rpm.

Once you finally get your standalone and upgrade your head, you can change your exhaust housing to .63.

aen

<< 70 trim with .63 AR

i spool at 3500, perfect for me!

B_Real45

That's good, Aen.

I however would prefer to have full boost by then - not just spool. But our applications may be totally different.

tuffCookie

you can also use an e-manage ultimate to raise the rev limiter.

B_Real45

Wow I didn't know that - has anyone done this on our cars?

I know there are a few people on these boards that use G. Ultimate.

tuffCookie

yes, there are people who have done it in the past. if you do a search for e-manage ultimate and rev limit, you should be able to find the old threads.

our cars' rev limiter is a fuel cutting controlled rev limiter, not ignition. if it were the other way around, it wouldn't work.

noskatana94

I am running the AEM Standalone and running stock everything besides my wonderful 7lbs of Boost and I have the REV Limiter set to 7000rpm with a 7200rpm fuel cut and it has been flawless.

B_Real45

Very nice! Can you post a dyno graph?

Ace83

iTrader: (6)

x2 on the dyno graph.. I had mine set at 6500K, i would keep it that way till I upgrade my internals

jwaggz82

iTrader: (1)

only bad part is "if" you ever slammed it into the wrong gear by mistake ..... you done. I remember one time it did happen to me ( about 2 years ago ) and im GLAD i didn't have a higher limit.

People keep in mind that when the needle slams into the limiter there is a bounce. Eventhough people are doing it does not mean its safe on a stock engine .... keep that in mind. The other good thing about it is that with the s/c the higher you can get the RPM's means the more power you will be getting out of it.

Guru

I have soft limiter at 6800 and hard limiter at 7000 on most Hydra cars I tune but kinda pointless really. Peak power is at 5500-5600 RPM even on larger frame turbos like GT35R's. To go beyond 6000 is just putting wear and tear on the engine with no speed advantage. This is on the 05-06 motor. The 07-08 motors there may be a small advantage since peak power is a few hundred RPM higher.

Ace83

iTrader: (6)

^^ Thats true, after 6K no more increase in power noticed on my graph though there is no drop in hp. Question, what motor upgrade will make raising the rev limiter an advantage? cams, pistons or ??

08superwhite

on my 08 on my dyno graph my hp was still climbing when i hit redline. my torque just leveled off at redline. this is on the stock rev limiter

B_Real45

Guru,

Is that true even when using larger exhaust housings?

paul_dezod

Too many variables to say. Depends on turbine A/R, Turbo Trim, Manifold Design, Exhaust System, Head and Cam specs etc....

We have rev'd a few tCs out to 7800 RPMS and have made power almost all the way there. As said before, it depends on the above listed parts and conditions.

B_Real45

Right Paul.. that's obivous. I was referring to his GT35 comment. It's a fairly large turbo - and yet he was still not gaining any power in the upper rpms.

I was wondering if they had tried larger exhaust housings (all else stock or the same) - my understanding is that the larger exhaust housing will shift the power band to the higher rpms.

Maybe someone can do this experiment. Take a pretty much stock tC and put a turbo kit on - dyno that and change the exhaust housing and redyno - just to see the effects.

paul_dezod

Turbine A/R and design of the manifold will have all of the bearing in the world. Say a selection of an .82 A/R vs a .63 A/R will suite better to a higher redline.

Guru

Even on a 0.84 AR exhaust housing it is true. I will be trying out the 1.01 AR once available for the GT35R SS HTA.