How much boost could I run on my stock twins if i had these modifications. Apex Power FC, greedy sp exaust, down pipe, greedy stock mounted intercooler, a new engine with a vacum hose job just done to the turbos. please let me know. Thanks

 

17 psi w/ the proper tune.

 

You don't want to go over 15 psi with either the stock twins or greddy smic. You COULD, but after that you will accelerate the wear on the turbos & the efficiency of both. From what I remember reading on other people's dynocharts, after 15 or so the hp gain is very limited.

 

to get max boost from the stock twins(15psi) you need to have a good fuel pump and tune the power fc. be carefull you dont overload the injectors because the engine can get thursty & detonate. be carefull what boost controller you use so you dont have any boost spike problems. and after that you might want to rebuilt or buy yours self a new turbo. all the mods we mentioned will be good for 360 bhp

 

What he said^.

With the BNRs you can push it to 18, but the stockers make more heat than power at that boost level.

 

No comment...actually...i will comment....several people have made more great power with higher boost on the stockers. Some (several) people run 17-18 psi with no negative reports. There are many more people then boostn7 doing this...they come out of the woodwork everytime this topic is discussed. I have seen over 380rwhp with 120+ mph traps and low 11s from the stockers @ higher boost. So they do make more power with higher boost. That is obvious. I think what people question is the reliability of them at higher boost.

No offense to anyone but it seems to me the people that have upgraded to modified twins claim the stock twins cant hang. Meanwhile people that remain stock twins up the boost with good tuning and are running similar power (alittle less) to the upgraded ones. I think the point that the upgraded guys make is that its not as reliable. Meanwhile the poeple running the the stockers at 18 psi arent making any complaints about reliability. This topic fustrates the hell out of me.

Having said that...i run 15psi on my stockers sometimes. Mostly 13psi. Thats all you need on the street anyways. If you want to run 15psi and higher you are gonna need to upgrade the injectors to atleast 1300cc's. Also, i have come to learn that an ignition is sometimes requirred to run this much boost as well. some people dont require an ignition while some people do.

Conversely to my stance on this subject, i probably will upgrade to BNR's one day....go figure.

 

Running more than 12lbs of boost on stock twins will cause premature wear period end of story. I'm not talking about a couple of pulls at 15lbs but continuous driving at 15lbs. After 20k miles or less at 15lbs of boost your turbos will be leaking oil and the wear begins. And you will loose power because of the heat that they generate at that power. Yes sure they can make big power on a dyno for a couple pulls but keep doing it for 1/2 hour continuously. IMO the only way to make lots of contiuous power reliably is with a single.

 

i ran fifteen pounds regularily....three sets of turbos later i went with the m2s...have been running them like stink at 16-17psi with no leaks no squeaks and no problems.

with all the right mods its possible as boostn is proving...but there are many many more people who have lost sets of turbos running them past fifteen psi than those who have not.

go with the upgrades...they produce less heat at boost as well.


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