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The mkiv Supra Owners Club

Over boosting???


Matt B

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All,

Just had my full decat, FCD and Nur spec fitted and am now hitting up to 1.3 bar on the gauge when the second turbo kicks in. Is this too high for standard Jap spec turbos? Haven't had the car on the RR yet to check fueling but will be doing this in a week or so. If the fueling is okay is it safe for me to run this level long term or will it shorten the lives of my turbos/engine?

Thanks in advance.

Matt B

:cool:

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Matt you should be OK. Lots have done it. The life of the turbo's at higher boost will be reduced, but again some have them on still going strong. If you intend to continue running 1.3 then a better fuel pump and a FSE fuel pressure regulator is a must really. Also, 1.3 is the max boost you should run, and then only on Optimax.

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No worries mate, when I spoke to Far he said he was going to meet with you earlier in the day. Do you live down by me in Redhill? If so we will have to meet up again some time.

Quite funny really cos when I saw your pic in the name to faces thread I thought you were joking and it was a wind up, you've certainly got the right plate.... Very cool:cool:

 

Cheers

Matt B

:)

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Roy,

Sounds good mate, will keep an eye open for that one.

 

Branners,

It's normally on boosting to 1.2 or just a little over. If I put my foot flat when allready travelling at high speed 85+ then it seems to go higher. If I get a better fuel pump and FSE will I be okay running high boost?

Cheers

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Its really the EGT temperatures which cause a problem with the high boost and what happens is they spiral out of control the longer the boost level is held for (normally associated with running lean). You can hit 1.3bar pretty much all the time but if you hold it there for a top speed run or similar thats when the EGTs just keep going up and up which in turn melts a plug or piston and it goes seriously downhill from there. So long as you keep using SUL or Optimax then 1.3 max should be fine, I used to use octane booster and SUL all the time when running up to 1.4bar.

 

If you get a decent fuel pump and FSE you can push the fuelling harder and in general it does work most of the time. Theres at least 1 member who lost an engine because his FSE wasnt doing what was expected so really the best option is to uprate the injectors to 550cc ones if you want to be 100% safe, but with 440c injectors I would say you should be fine so long as you dont try any 180mph runs up hills.

 

JB

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My J-Spec TT (full decat, FCD, Super Drager) has started to creep up to 1.3 peak (only ever seen it above 1.2 once before) but so far 1.3 is the highest its hit. Tonight in 2nd (auto) with manu mode on and overdrive off, it was 0.8 on first turbo and then as the 2nd came online it went to 1.3, but I had to ease off so don't know if it would have held that or if it would have been the peak....... I guess I need the better fuel pump and FSE too then! And a restrictor ring and boost controller if it goes any higher I guess?!!

 

Question is though - after all that ;) - does it crucify your fuel consumption fitting the pump and FSE?

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