boost rises w/ 3" exhaust?
 

My friend said that when he installed his 3" exhaust on his 10AE, the boost went up to 15psi's. Is that possible? He doesnt have the car anymore, and I'm about to buy a 10AE with a RB straight exhaust, but this ones only boosting 6-8psi without a boost controller. thanks...

~Dave

you will get boost creep with a open exhaust.. I'm not a turbo guy so I dont know what you can do to prevent it, or keep it down. maby his wastegate wasent hooked up correctly?

Well this depends on multiple factors but in general yes, using a less restrictive exhaust will up your ability to boost more; even without changing anything. A few precausions thought, you'll need a fuel cut defender, the stock TID sucks b@lls, and the S4 wastegat is totally too small for anything more than 9 psi IMO. I hope I have my facts correct..so I will state for the record that this is what I have experienced.

Hope that helps. For a more direct answer or my experiences email me at curtislamasters@gmail.com or PM me.

Curtis

just gotta port the waste gate bigger to prevent boost creep thats all

larger diameter, more free flowing exhaust will cause the boost to creep more, i was seeing over 16psi with my 3" exhaust and upgraded TID.

if his is only boosting 6-8 then the exhaust is not very free flowing or the wastegate has already been ported.

What TID you got?

dude...you were seeing 16 psi??? excuse me if im wrong but i thought the stoke turbos were only good till 14...perhaps it was a bad thing you were seeing that much boost?

he didnt say that seeing 16 psi was a good thing with the stock turbo, he was just stating that indeed the boost does go up because of boost creep.

i have a custom 3" TID i made up to the turbo inlet fabbed up from some aftermarket intake kit.

yes, it's not a good thing seeing 16psi with a stock turbo. i also ported the turbo exhaust runners for more flow but my wastegate porting was inefficient enough to keep up with the flow so i took it easy on it until i was able to port it sufficiently enough. the stock turbo can push upwards of 20PSI, its efficiency range is only up to about 12-13PSI, anything higher than that is just risking your motor.

I have the a 10th AE with SS auto chrome exhaust and if I don't watch out it will boost up to 15 PSI. I don't know if you could call it creep, its more like it jumps to 15. if the guy is only boosting 5-6 psi then he already ported the waste gate and he probably has a FCD. there is lots of info on all this stuff. just search. :)

The guy has a 10AE, but he has S5 jspec turbo and manifold. I'm not sure if he has the S5 wastegate, is it even possible to still use the S4 wastegate?

So either the guy has a ported wastegate, or he doesnt have a 3" exhaust right? I was under the car, and the exhaust piping looks massive.

If he has an S5 turbo, then he has an S5 wastegate, it is not an external wastegate. J-spec is the same as the american turbo in all FCs. About the ONLY thing besides exhaust and intake resrictions that can limit boost is the wastegate. A FCD does not limit boost. If he has an S5 turbo he may just be runing on the wastegate spring alone which is likely, if he is still runing S4 boost sensor and S4 CPU. But he would still be boosting over the 5.5 spring rate with open exhaust.

Likely a ported wastegate.

Yea if he's seeing close to stock boost levels with a 3" exhaust, he's got a ported wastegate already...

n/m

Thanks

i was seeing about 12ish with just 3" exhaust but it would creep higher in 4th then with tid(3" tid from home depot ) id hit 15 ( end of gauge) near the top of 3rd and 4th

which is WAY to much for stock injectors and stock fuel pump... but i was crazy X_x.


with the rtek and 720 you should have ample fuel for 16 psi at least! but heat will become an issue above 14 psi on stock intercooler and turbo. boost creep isnt too bad ,but you can get boost spikes which are really bad.

if it was my car id have it running at 12 all the time..... but to be on safe side you could set it low, and it will take a long time to creep to dangerous levels( wont get too high unless your doing really long pulls, in 4th or 5th) so id just avoid long pulls, u can rip threw 1-3 fast and you shouldnt have any problems at all.