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The mkiv Supra Owners Club

RR size


The Raven

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You get higher egt's doing it that way as its a higher restriction, mines 64mm RR runs 1.35, 3" decats and 4" single box exhaust, no boost controller needed

 

But 1.34 is too much? thats pushing the limits of the stock injectors, nevermind the ceramic turbos is it not?

 

I know it's not ideal, but it's the usual way of doing BPU as it gives greater control over the boost, and won't overboost if done right.

 

Im also most certain that the EGT's will not be drastically different between the two?

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But 1.34 is too much? thats pushing the limits of the stock injectors, nevermind the ceramic turbos is it not?

 

I know it's not ideal, but it's the usual way of doing BPU as it gives greater control over the boost, and won't overboost if done right.

 

Im also most certain that the EGT's will not be drastically different between the two?

 

1.4 what has been proven by a couple of members i know to be a safe limit, ive been running 1.35 since april, (was running 1bar for 3yrs prior) and i kick its head in everywhere, done quite alot of miles in that time, its still perfect as it proved on the dyno on saturday, its on stock original 22yr old jspec turbos and stock 440cc injectors fueling is bang on

 

the egts are obviously higher when running a smaller ring, it is like blowing through a straw compared to a hosepipe, the size might not sound that much in terms of inches/mm but the overall space opened is significant, my RR is 2.5" compared to 2"

 

overboosting means more power = more speed :D

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1.4 bar, even if the stock turbos will produce that, will mean overspeeding and terrible turbo efficiency, they will be right off the efficiency map, thrashing the air and heating it significantly. 1.2 bar is definitely the safe limit in my opinion.

 

But 1.4 is more, so it must be better! :)

 

Sounds better down the pub, anyway.

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A supra will only boost to 1.2bar if the cats are taken out.

 

3seconds at 1+bar will hit fuel cut, you need to fit a FCD to stop this.

 

with RR only, it's a very fine art to take enough metal away to get it exactly to 1.2 bar, this will change with air tempreture also, which is why its usually said best to fit a 1bar RR and raise with a controller.

 

As you can only raise boost with a controller, not lower it.

 

If you ran a supra with no restrictor ring and no cats, it would overboost, sometimes to 2bar, bye bye turbos.

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This is what I'm saying. I have a double decat on the exhaust, it's an RSR one. It has a 1.2 bar restrictor ring... Therefore shouldn't it boost to 1 bar and hit the fuel cut as it can go to 1.2 bar? I don't know if it's because it's vvti and has a MAF that it stops it hitting the cut but seems odd

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This is what I'm saying. I have a double decat on the exhaust, it's an RSR one. It has a 1.2 bar restrictor ring... Therefore shouldn't it boost to 1 bar and hit the fuel cut as it can go to 1.2 bar? I don't know if it's because it's vvti and has a MAF that it stops it hitting the cut but seems odd

 

Do you have an fcd?

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Depends how restrictive the RSR is, i seem to recall they are.

 

Dont you have a boost gauge? seems silly not too if you have double decat? If the exhaust is restrictive it would have the same effect as having the cats in, hence no increase in boost.

 

Do you have a Mines or Blitz ecu? those have built in fcd's

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Well it's Abzs old car. The weird part is it has no boost controller or FCD or boost gauge for that matter but it's definitely not hitting fuel cut and it has a double decat and 1.2 bar restrictor ring.

 

What size RR is it? Is it a 2inch? If it is you are most likely only boosting to just under 1bar

 

- - - Updated - - -

 

Hitting fuel cut sucks :(

 

Shhh you:p

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