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The mkiv Supra Owners Club

boost issue, Any supra specialists on the south coast?


squiffy

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Hi guys

 

Since picking up my six speed, it's not been as quick as i expected. I found it hard to judge at first as it has been a year since i've had a quick car!

 

i fitted a boost gauge at the weekend and confirmed what i thought! I'm only making 0.55 bar boost maximum. When i accelerate the gauge goes up to around 0.5bar on the first turbo. then at 4k revs, i feel the changeover as the 2nd turbo comes in. there is an increase in power, yet the boost stays at 0.5bar. sometimes spiking to 0.6 if i floor it on the motorway.

Im thinking its a boost leak but also Its making me think i have a problem with the sequential valves?

 

I'm going to have a look over the weekend to check the obvious bits, but worst case, Does anybody use any garages within reasonable distance from Portsmouth they would recommend?

 

mods on the car:

apexi intake

hks cat back

full decat

dump valve

 

i have some bpu bits to bolt on but obviously want to get it doing what its supposed to be before modding it further

any help / pointers are appreciated :)

Edited by squiffy (see edit history)
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First few things to check are:

 

1. Vacuum lines for splits, breaks or disconnecting

2. Your VSVs particularly the exhaust gas bypass valve which spins up the second turbo

 

The VSV's can fail and/or they get brittle after years of sitting next to the turbos and the spiggots can break on them.

 

I would check these areas first.

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