Max boost running a TD06 20G on a '03 WRX?

[encino281536]

I've recently started upgrading my '03 WRX
- I've swapped out the exhaust with a full aftermarket one (4-to-1 headers, uppipe, 3' downpipe/midpipe/muffler)
- Upgraded my fuel pump to a Walbro 255 LPH
- Upgraded to Perrin fuel rails
- stock OEM internals
- no piggy back ECU (I do my own flashing)
I have a 02-06 STI TMIC, STI 565cc injectors and a TD06 20G turbo on the way

I've been running 15psi of boost for a while now with 18psi being my limit
Anything higher would shorten the life of the turbo and change my air density considerably
With the above mentioned, I'd like to know the max boost I can run without blowing my engine or having to upgrade to Forged Pistons & Rods

[encino281536]

02-06 STI TMIC is from CXRacing
20"X11.5"X4.5", 2.75" Inlet & Outlet

[mosc]

well, you'll probably be fuel limited. Do you have an EJ207 or an EJ205? What octane gas do you use?

[Kjott21]

STi injectors are not going to be big enough to run a lot of boost out of that turbo.

Boost isn't in and of itself the factor that limits the safety of the motor. It also has to do with how aggressive your timing is and how lean you run the fuel. Longevity is dependent on the tune.

I don't even want to guess at how much boost you can run from that turbo with that small of injectors.

[encino281536]

I'm running 97 octane here
I have a EJ205

[encino281536]

After buying the 565cc injectors, I started looking around for 630cc / 650cc
A friend managed to get his EJ205 with a VF34 in the 12's at the track, running 97 octane and a custom map
The boxer engine is pretty tolerant when the fuel mixture is 'rich'
He told me his fuel map gets a little 'richer' with each step
Let's say I get 600+ cc injectors to compensate, what would anyone's guess be?
I know for example a Honda B16 can run up to 15psi boost on OEM internals

[Kjott21]

Originally Posted by encino281536

A friend managed to get his EJ205 with a VF34 in the 12's at the track, running 97 octane and a custom map
The boxer engine is pretty tolerant when the fuel mixture is 'rich'
He told me his fuel map gets a little 'richer' with each step

This statement makes no sense to me. It might be a language barrier. Most stock motors make the most power at around 11.1 AFR. It will run ok richer but not make the most power. A VF34 is TINY in comparison to the 20g.

Originally Posted by encino281536

Let's say I get 600+ cc injectors to compensate, what would anyone's guess be?
I know for example a Honda B16 can run up to 15psi boost on OEM internals

15 PSI from a VF34 doesn't have the same amount of flow as 15 PSI out of a 20g. Any upgraded turbo is going to decrease the life expectancy of your motor. There is no magic number for how much boost the OEM internals will stand. They will take a lot of boost for a little while or a little boost for a long time as long as the tune is good.

Talk to this guy: Subaru WRX Forum: WRX Forums - View Profile: EJ Rex
He's running a TD06 20g.

[encino281536]

I'm just relaying what my friend told me
I completely agree with you
The whole point of running rich is to cool off your internals (pistons, cylinder walls), reducing hotter exhaust gasses and detonation, right?
You are also correct on the AFR - 11:1
Your statement "They will take a lot of boost for a little while or a little boost for a long time as long as the tune is good." is exactly what worries me
I wouldn't want to upgrade to a 20g to run at a lower boost level

[encino281536]

Thanks!
I've contacted EJ Rex

[Kjott21]

Originally Posted by encino281536

The whole point of running rich is to cool off your internals (pistons, cylinder walls), reducing hotter exhaust gasses and detonation, right?

Running rich will reduce detonation but can increase your EGT's as well. Timing has an effect on your EGT's as well. There are a lot of factors that affect the safety of your motor and are mostly dependent on the tune.

Originally Posted by encino281536

Your statement "They will take a lot of boost for a little while or a little boost for a long time as long as the tune is good." is exactly what worries me
I wouldn't want to upgrade to a 20g to run at a lower boost level

All I meant by that statement was if you run a lot of boost your motor isn't going to last as long as it would if you are more conservative. 18 lbs of boost out of your stock turbo will make less power than if you run 18 lbs out of your 20g. The power comes from the extra flow. I personally wouldn't run more than 20 PSI on the 20g maybe only 18. It all depends on how the motor reacts.

Do you have a tuner or are you planning to do it yourself?

[encino281536]

I really appreciate your help, these are the answers I've been looking for
When I started out, I just wanted to better my exhaust flow, make the car breath a little better
But as things went along, the mods are becoming a little more aggressive
We've got guys here, importing ### spec subaru's, evo's, supra's, skyline's
All with stroker kits, modified ECUs (mines, ECUTek), exhaust, upgraded turbos...leaving me in the dust
Toyota Starlets, Supra's and Skyline's that are doing 11's at the track
I'd like to able to hold my own on the streets with these guys

With a few mods & a good tune, I should be able to get performance up
What would you recommend to get my EGT down in this case? leaning my map a little, adjust the timing?

[encino281536]

I have a tuner that is going to help me with my ECU

[baller_v24]

You should of gotten a performance intercooler. The STi tmic is not going to do much for you.

[encino281536]

APS core dimensions - 20.07" x 7.5" x 4.5
STI TMIC core dimensions - 20"X11.5"X4.5" (although the APS has a better design)
You're referring to a FMIC then, right?

[newtothegame]

Which one flows better? Size isnt always what matters. I know its cliche but its true.