How much boost can I run safely

[Pr SunGod]

I have a Microtech MTX-8 engine management system, APEXi AVC-D boost controller, with HKS external wastegate controlling a TO4 turbo. Right know I'm running 10 psi (street setting) which is way low (even though I have still teached a few things about racing to some Corvettes, Camaros SS, Saleen Mustangs, and the occasional Turbo CRX...but that is mostly do to the good fuel tuning) I would like to know if I can safely raise the boost to about 18 - 20 psi on the Apexi, without any additional tuning of the Microtech?
Thanks for your help.

(My mods are listed in the profile)

 

[larryd]

how much boost you can run really is irrelevant becuz with everyones setup its going to be diff.. its more about how much can you make without breaking something.. the figure out how much boost to run to get that much power.. if your still on the stock internals then around 400bhp is the round # most people would say.

 

[2-0turbo]

I'm curious as to why you have this well-equipped car with a stand-alone ECU and you are asking this question. Does someone else do all your modifications and tuning for you? I'm not smacking on you, but you have a pretty advanced setup and are asking a very basic question. Most people with your setup know about what they can run and experiment to arrive at the optimum.

 

[niterydr]

this post seems to me:...


my appologies...

not to be mean, but this doesn't add up, either the car was built for you and you should go back to the shop and ask this question, or please explain the setup a little more.
otherwise its 70psi, tops.

btw you look like you have enough fuel to flood new york in one swoop.

 

[larryd]

niterydr.. we do not tolerate what you included in your posts around here.. please refrain from doing that in the future.

 

[Pr SunGod]

My mechanic moved to the U.S., and I still havent found one as good as him. He was the one that built the car, and I supplied the $$$. I haven't had any time to go to a Dyno and mess with the ECU and tune it, so I just wanted to know how much it can take without extensive tuning.

 

[Pr SunGod]

And I have upgraded internals (rods, pistons, cams)

 

[niterydr]

geez..this is a really hard question to ask without first hand knowledge of the car (or seeing it), you really need to get on a dyno to see what you can run, to little boost, and you could compressor surge at a given rpm, or flood the motor, to much, and you could run lean, to little, the car will be slow, to much also slow due to cut timing.
explain the microtech a little more, what are the current settings? readings for a/f? o2? timing advance? etc..etc..

 

[Enigma_Man]

What are you talking about niterydr?
Compressor surge and flooding the motor? Umm... No, that wouldn't happen at all. Running the turbo at a very low boost is perfectly fine with no ill effects whatsoever, short of running slower. Anybody else more knowledgeable back me up on that?

-Jesse

 

[niterydr]

hmm...
lets say you have all the fuel in the world to flood a river...and you have no air to mix with the fuel, where will the fuel go? in the motor perhaps??
i know fuel does get returned back to the tank, but with larger cc injectors if the fuel isn't compensated correctly, their will be excess fuel in the motor (thus 'flooding it')
also...
the compressor surge thing..
I didn't mean 'too little of boost' i meant under wrong conditions, if his turbo would spool at to low of an rpm it could cause an unstable condition. Running higher boost (than 10),(which is good on larger turbo's, puts them more in their effiency ranges) can prevent this somewhat...i dunno i can't explain what im trying to say..
but i assumed he had a large turbo by the t04 part, but it could be any size turbo for that matter...so i'll just be quite until i find out more about the car/turbo size.
**zipping mouth**

 

[Enigma_Man]

Aah okay then. I was assuming his air/fuel situation was tuned for his current level of boost, cause I didn't see him mentioning that. That's why I don't think it'll 'flood' at his current low boost levels.
But yeah, I didn't have enough info either I was assuming that his air/fuel ratios were correct at the moment, right fuel for amount of air and all that.

-Jesse

 

[Pr SunGod]

Yeah, right know(at 10 psi boost) I'm running a good A/F ratio; but I was wondering if it would stay that way, when I raised the boost?

 

[niterydr]

Originally posted by Pr SunGod
Yeah, right know(at 10 psi boost) I'm running a good A/F ratio; but I was wondering if it would stay that way, when I raised the boost?

odds are it won't, you'd need to retune, 10psi is such a low boost amount (especially for your mods) that you'd need to adjust alot to run higher boost (like, actually give the motor some of the fuel you have).
all you need is a dyno and a wideband, and you can run as much boost as you want

 

[GST4U2NV]

backing up niteryder,motors can be flooded and break i have seen it first hand.