lifted boost to 16psi. is it safe?
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On '93-96 WRX's, according to MRT, they said, don't run them over 16.5 psi, or its only a matter of time before you'll have a bottom end failure (not the turbo).
In my last few posts, I changed the subject, as I was speaking about Mitsubishi turbos in general (not necc on WRX's). If you compare the flow charts, the TD05-16g (small 16g, like what comes on early WRX's) rapidly loses efficiency after 18 psi...these turbos are extremely popular with the DSM guys over here in the States (Mitsubishi Eclipse/Eagle Talon TSi/Plymouth Laser, and 3000 GT VR-4/Stealth RT-turbo).
The big 16g (came on Evo 3) is far more efficient over 18 psi, as is the 18g compressor wheel.
I personally believe that with careful mods, and proper gauges, you can run over 16.5 psi. MRT's probably sees so many detonation-related failures because people indiscriminantly up the boost without proper accompanying mods.
If you have bigger injectors, fuel pump, better intercooler (FMIC), boost controller, engine management, gauges, etc, you can probably get away with 18-20 psi on a stock TD05, as long as you're running ~100 octane, and you tone down the ignition timing under heavy load/boost. If you add water injection, you can probably run even more boost. Not sure if John Banks is the fellow I'm thinking of, but the dude formerly known as Cossie Convert is a good example of a TD05'd '95 WRX RA running 26 psi. He's eliminated his 90 degree elbow, among other things. But he's also an experienced race car builder, and his high boost RA is quite the exception.
Another consideration is compression ratio. '93-96 jdm WRX's sport an 8.5 to 1 CR. Subsequent WRX's and STi's were lowered to 8:1. But many UK Impreza Turbos appear to be 9:1. Lower CR means you can safely run more boost, but it tends to aggrevate off-boost response (lag), with the tradeoff of bigger peak hp figures due to higher boost. Of coures, these '97+ models generally came with a smaller turbo, so lag remained a non-issue.[/b] But the point is, 18-20 psi might be fine with an 8:1 CR, but don't expect to run as much boost on your WRX/Impreza turbo if it has an 8.5 to 1 CR...And if it has a 9:1 CR, forget it!
[Edited by annointed - 11/1/2002 2:59:00 PM]
In my last few posts, I changed the subject, as I was speaking about Mitsubishi turbos in general (not necc on WRX's). If you compare the flow charts, the TD05-16g (small 16g, like what comes on early WRX's) rapidly loses efficiency after 18 psi...these turbos are extremely popular with the DSM guys over here in the States (Mitsubishi Eclipse/Eagle Talon TSi/Plymouth Laser, and 3000 GT VR-4/Stealth RT-turbo).
The big 16g (came on Evo 3) is far more efficient over 18 psi, as is the 18g compressor wheel.
I personally believe that with careful mods, and proper gauges, you can run over 16.5 psi. MRT's probably sees so many detonation-related failures because people indiscriminantly up the boost without proper accompanying mods.
If you have bigger injectors, fuel pump, better intercooler (FMIC), boost controller, engine management, gauges, etc, you can probably get away with 18-20 psi on a stock TD05, as long as you're running ~100 octane, and you tone down the ignition timing under heavy load/boost. If you add water injection, you can probably run even more boost. Not sure if John Banks is the fellow I'm thinking of, but the dude formerly known as Cossie Convert is a good example of a TD05'd '95 WRX RA running 26 psi. He's eliminated his 90 degree elbow, among other things. But he's also an experienced race car builder, and his high boost RA is quite the exception.
Another consideration is compression ratio. '93-96 jdm WRX's sport an 8.5 to 1 CR. Subsequent WRX's and STi's were lowered to 8:1. But many UK Impreza Turbos appear to be 9:1. Lower CR means you can safely run more boost, but it tends to aggrevate off-boost response (lag), with the tradeoff of bigger peak hp figures due to higher boost. Of coures, these '97+ models generally came with a smaller turbo, so lag remained a non-issue.[/b] But the point is, 18-20 psi might be fine with an 8:1 CR, but don't expect to run as much boost on your WRX/Impreza turbo if it has an 8.5 to 1 CR...And if it has a 9:1 CR, forget it!
[Edited by annointed - 11/1/2002 2:59:00 PM]
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Joined: Jan 2002
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From: In a house
Hehe sory Tone, its just been a long week for me as I've been in Uni non stop. Worse still I'm relegated to commuting using busses and train to my Uni every day and by the time I get back, I'm knackered as hell, hence my inability to comprehend posts. 
I want my car back.
I want my car back.
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