How much boost am i able to run?
I have 680's and can support up to spikes of 29.5psi.
You have to keep in mind that after about 25psi, the turbo is doing nothing but blowing a ton of hot air. You need to realize that after a certain point, there is diminishing returns with boost on the stock turbo.
Once you are tuned, with 93 gas and those injectors, you should try to aim for around 25 psi because really any more and your just blowing a bunch of hot air.
You have to keep in mind that after about 25psi, the turbo is doing nothing but blowing a ton of hot air. You need to realize that after a certain point, there is diminishing returns with boost on the stock turbo.
Once you are tuned, with 93 gas and those injectors, you should try to aim for around 25 psi because really any more and your just blowing a bunch of hot air.
Well what turbo are you running? is it the Evo 8 turbo or 9 turbo? I know with the 8 turbo after about 23-24 psi your simply blowing hot air and making no true gains. Now the Evo 9 turbo is obviously bigger and I believe can support about 25-26 psi. Now it also comes down to what gas are you running, is it 93 octane or is it race gas. Because what you can run on race gas you cant run on 93 without serious problems(race gas you can run more psi). The 750CC will flow enough for pretty much anything either stock turbo can produce and the Walbro will as well. However, if you ever decide to switch to E85 then the injectors wont even come close for you will need a minimal of 1000CC and the Walbro will tap out about 25-26 psi on E85. Sorry for the long response but hope I helped.
Evolved Member
Joined: May 2004
Posts: 3,783
Likes: 0
From: Diamond Bar, California
^ You guys need to keep up with current debates.
From David Buschur "Daniel's car (my brother) with the stock turbo has low timing to get by with 30+ on pump. His car is probably down to 1-2 degrees but we are talking about a BONE STOCK turbo on 93 at over 30 psi on a daily basis for the last year."
From David Buschur "Daniel's car (my brother) with the stock turbo has low timing to get by with 30+ on pump. His car is probably down to 1-2 degrees but we are talking about a BONE STOCK turbo on 93 at over 30 psi on a daily basis for the last year."
Trending Topics
Newbie
Joined: Nov 2007
Posts: 26
Likes: 0
From: Tampa
^ You guys need to keep up with current debates.
From David Buschur "Daniel's car (my brother) with the stock turbo has low timing to get by with 30+ on pump. His car is probably down to 1-2 degrees but we are talking about a BONE STOCK turbo on 93 at over 30 psi on a daily basis for the last year."
From David Buschur "Daniel's car (my brother) with the stock turbo has low timing to get by with 30+ on pump. His car is probably down to 1-2 degrees but we are talking about a BONE STOCK turbo on 93 at over 30 psi on a daily basis for the last year."
Is that with a lot of water spraying on the intercoolers, water injection, or living someplace really cold? Outstanding numbers, either way; that's quite a tune--and is it worth the timing retardation, power-wise?
</mildly o/t>
I'm sure 30psi is a spike with a stock turbo, if the entire boost curve was shown, I'm sure you'd see it fall off to around 25psi or so.. Its just in order to get the boost, you have to deal with that spike.
But Dave has had the time and resources to try out a ton of stuff, so I would consider the information he offers as reliable, however It might be hard to duplicate his results without the right combination of parts.
Its not always about "how much boost" but how efficiently you can move that air through the induction, head, turbo, exhaust.. I have always said that the best way to make power is to reduce any and all restrictions and you can do amazing things with what you have available.
I would recommend using some form of closed loop boost control to maintain a flat boost curve, but that is just my personal opinion, that boost spike is good for a huge torque spike that would be useful in some situations.
But Dave has had the time and resources to try out a ton of stuff, so I would consider the information he offers as reliable, however It might be hard to duplicate his results without the right combination of parts.
Its not always about "how much boost" but how efficiently you can move that air through the induction, head, turbo, exhaust.. I have always said that the best way to make power is to reduce any and all restrictions and you can do amazing things with what you have available.
I would recommend using some form of closed loop boost control to maintain a flat boost curve, but that is just my personal opinion, that boost spike is good for a huge torque spike that would be useful in some situations.
Last edited by MalibuJack; Nov 14, 2007 at 06:58 AM.
I'm sure 30psi is a spike with a stock turbo, if the entire boost curve was shown, I'm sure you'd see it fall off to around 25psi or so.. Its just in order to get the boost, you have to deal with that spike.
But Dave has had the time and resources to try out a ton of stuff, so I would consider the information he offers as reliable, however It might be hard to duplicate his results without the right combination of parts.
Its not always about "how much boost" but how efficiently you can move that air through the induction, head, turbo, exhaust.. I have always said that the best way to make power is to reduce any and all restrictions and you can do amazing things with what you have available.
I would recommend using some form of closed loop boost control to maintain a flat boost curve, but that is just my personal opinion, that boost spike is good for a huge torque spike that would be useful in some situations.
But Dave has had the time and resources to try out a ton of stuff, so I would consider the information he offers as reliable, however It might be hard to duplicate his results without the right combination of parts.
Its not always about "how much boost" but how efficiently you can move that air through the induction, head, turbo, exhaust.. I have always said that the best way to make power is to reduce any and all restrictions and you can do amazing things with what you have available.
I would recommend using some form of closed loop boost control to maintain a flat boost curve, but that is just my personal opinion, that boost spike is good for a huge torque spike that would be useful in some situations.
3000ways as we all know thats a spike and its something that is not obtained throughout the entire rpm band. I mean could you imagin running 30-32 psi on a stock 9 turbo from spool until redline or whenever you switch gears? I personally dont think its feasible nor it is good for the turbo, I would think your blowing hot air.
Thread Starter
Evolving Member
Joined: Nov 2007
Posts: 303
Likes: 0
From: Orcutt/Santa Maria CA
its the stock evo 8 turbo, and im thinking about getting a cobb tuner and i want to upgrade the turbo but i dont know what i want to get yet. i want the biggest fastest spooling turbo those injectors will handle. and is the cobb tuner really worth the money? i have friends who are brothers that both drive subies and have the cobb tuner and it did alot and they have a studderbox thing that came with it which i thought was really cool. and i do plan on getting the car tuned here by a place called harmon motive once i get everything thrown on the car that i want.
