most boost on stock internals and turbo?

[mr2envy]

does anyone know how high you can set your boost/psi on stock internals and stock turbo but with like fuel upgrades and others? cant the stock internal only take 15psi right? well safely

[JekylandHyde]

How much boost the stock internals can handle depends on what turbo you are using.

With the stock CT26 turbo, I would never go over 15 psi of boost. The turbine side of the CT26 is too small and you start creating to much heat above 15 psi.

I have run as much as 24.5 psi of boost on a 100% stock engine with a T3T4 turbo (using race fuel, water injection and an appropriate fuel system).

[SHORTYBOY113]

how much boost do u think would be safe with a greddy side mount and a ct20b turbo

[JekylandHyde]

I would not run over 16 psi with any turbo without water injection ever again.

I am not familir with the ins-and-outs of the CT20B, but you are taxing the OEM fuel system around 280 rwhp or so.

The issues you have with upping boost is do you have enough fuel and are you increasing your chances of detonating.

[mr2envy]

wow thats alot of boost on a stock engine. see i always thought that you couldnt run more then 15 cause thats what everyone was saying and then some guy said he would run 17psi and i didnt think you could so i wanted to find out what you guys thought. he hyde if you said youve ran 24.5 boost and with stock internal how come your running 22psi right now?

[JekylandHyde]

Because I was running 24.5 psi last season on a smaller turbo. I went to a larger turbo so I am making more power at less boost.

We are starting the season at a lower boost level in order to preserve the engine. I have sponsorship agreements which require me to make 12 events. It would do me no good to put downs 25 psi, 400+ rwhp and blow the car up the first time out.

With the bigger turbo we put down 380 rwhp @ 20 psi. last year I put down 351 @ 22 psi with the smaller turbo.

Toward the end of this season you will see my boost being increased if the engine is still healthy.

If all goes well, we will be looking at 30+ psi of boost next year on a rebuilt engine.

[JekylandHyde]

... you may find this thread entertaining:
http://www.automotiveforums.com/vbul...d.php?t=408775

[mr2envy]

o gotcha dang how fast do you think youll be going once you build ur engine and put on the 30 boost?

[mr2envy]

hey quick quisten how did you deal with fuel cut i know alot of ppl get those machines to do it but with a bigger turbo how would that deal with it?

[JekylandHyde]

I should be in the 10 second range 1/4-mile once we build everything up.

Fuel cut is controlled by the OEM map sensor ...simply cork the vac line going to it and you remove the fuel cut protection. Fuel cut has nothing to do with the size of the turbo, but the amount of boost. Once you hit 12 psi, it kicks in.

[mr2envy]

well yea but like doesnt that make you engine unstable or something? like somewere it said that you wont accuratly be able to control the boost and it could break your engine

[JekylandHyde]

On the USDM MR2s, the OEM map sensor only does two things:
1. Control fuel cut.
2. Control the OEM boost gauge.

If you cork the vac line to the sensor, you will lose the OEM boost gauge and fuel cut.

I am now racing in my 4th season with that line corked ... actually, I got rid of it altogtether now that I am on a stand alone ECU.

[mr2envy]

what about jdm? do they have it too? yea i was just thinking the sam removing it all together i mean if your not going to use it anyways by just plugging it take it out. put in a aftermarket boost gauge (that would work right?)

[SHORTYBOY113]

yea u just have to put in a gauge that is the right size i cant think of it tho. i think its 58mm