Turbo boost drop's out at 5500 rpm @ 9 psi

Turbo boost drop's out at 5500 rpm @ 9 psi for those that have had 7mgte's

#1 MA70 DANNY

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Posted 29 March 2008 - 10:47 PM

ok, so i've just boosted my 7m from 6 to 9psi it seems to drop pressure at 5500rpm back to 7 psi and lower progressivly , what is causing this, do i need a turbo upgrade or what? its got non standard piping (2 1/4 and 2 1/5 inch) and a big intercooler, i've heard the ct26 is good for 14psi so argghh???? i've also heard the garrett T44 is a good turb's any info on this matter would be greatly appreciated

cheers, ma70 danny

#2 IcE

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Posted 30 March 2008 - 05:10 AM

Interesting...

after market ECU? Boost cut? uh, mebe your piping is too big?

We could go worse and perhaps suggest that the turbo has shagged it self? Has it got shaft play, are all the fins on the wheels ok? is it maintaining oil pressure?

I really dunno man, thats got me beat :(

Hope you find out what it is!

Cheers,

IcE

#3 Reaper

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Posted 30 March 2008 - 09:59 AM

Hi Danny,

I don't know this engine at all really.

Is it possible that the snail is simply nosing over ie. can't pump any more air?
How much boost was it able to push before this recent behaviour?

What is the stocker good for on other known good 7M's?

My turb trails off due to the recent headwork now, always used to hold 23psi to red but not now.

GEE

#4 ma61turbo

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Posted 30 March 2008 - 08:29 PM

How did you increase the boost? Bleed valve? EBC? Discounting the turbo being stuffed maybe there is something wrong with the boost controller. The stock CT26 on the 7m in my old ma61 was very strong at 11psi, i would expect a good ct26 to be no different.

#5 250Pluss

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Posted 30 August 2008 - 09:17 PM

Dude..........it's a7M thing,for that matter most turbo cars suffer from this phenonemon,don't worry it's normal.
The main reason is the manufacturers of our Supra,have chosen a very mid range & low down power curve to get this lump of a car moving off the mark,so turbo sizing compression ratio & the main culprate 'breathless' cam profiles with bee's willy lift are all in part to blame.
If you want to play with more top end, adj. cam gears & exhaust improvements will help,but a 7M is a grunty,torquey piece of work so, on a std. engine you may as well
keep on developing that side of things they do well.......
................................................................................
ta Brenton :to_become_senile: