For anybody who has ran a stock evo 9 turbo on an evo 8...how fast do you see boost on your stock 2.0L?

My setup isn't anything special but always seems to spool super super fast. Maybe too fast. If I load it up in 5th gear I can get 21psi by 2500-2600 rpm...this seems unusually fast compared to other spool threads I have seen. This is on the stock manifolds but with deltacam 272 regrind cams and e85. Seems to surge quite a bit too building boost this fast.

 

Your really lugging the engine by doing this and I don't think its very happy. Do that often and your asking for problems.

 

5th gear pull for the win.

 

yeahh... i wouldn't be flooring it in low rpms in 5th gear buddy.

 

Instead of the turbo spooling quickly in 5th, I would be worried more with windowing my block doing pulls in 5th gear...

 

Boost is compounding (more boost in = more exhaust out = more boost in etc). Pulling in 5th just means you take so long to get to 2500rpm you can compound that much boost in that time.

Also keep in mind that you are measuring boost at the throttle body, not the engine. Taking in as much boost as you can at 2500 rpm (not much) will provide a lot of resistance which will aid in building pressure in the throttle body and push your measured value up.

As others have mentioned you are putting your engine under a lot of strain by putting it under that much load at that rpm. Usually when you combust a lot of air and fuel the energy gets transformed into acceleration, but when you are in a higher gear it is more difficult to turn it into speed. All that energy has to got somewhere, I'd guess your rods and you don't want those taking more energy than they should.

 

If it's tuned right, there is NO problems with doing this.
I make 25psi boost at about 2300rpm in 5th gear with stock turbo and my 2.3, it's lots of fun!

 

Sup rods.

 

I think most people have caught it already, but yes, since your in a higher gear you have more time to build boost, so thats why you are seeing it at a lower rpm in 5th gear than say 3rd.

Now if it's any different than your evo 8 turbo, which I'm guessing is why you started this thread, it could be due to the fact that your 8 turbo bearings were on their way out, or maybe you have some dings etc in the compressor blades? even a leak on the old setup may explain it. IE i don't think the 9 turbo will spool noticeably quicker given the setup is the same.

Also I would second everyones comments on the rods as they seem to be the weak point on these stock engines. At lower RPM for a given load, the rod will see more compressive load (think buckling) than at a higher rpm. The rod bearings will see this higher load as well, and since they are spinning slower, they don't build the same oil film pressure than they would at higher rpms, meaning theres a higher likely hood of wearing out those bearing sooner. On a stock block & bottom end (what i have) and in 5th gear, I typically never go full throttle until i'm above ~3000 rpm. Not to say it's hurting anything, but I just feel better not doing it.

 

hit it right on the head.

 

I figured the rods wouldn't be thrilled with this. I am looking into some holset options now...thanks everyone

 

I am beyond jealous of your spool. But I am on a FP black not a stock turbo.