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The mkiv Supra Owners Club

BPU (Basic Performance Upgrade)


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The fit is back to front on a UK spec, you can make it fit but I think you'll need a jubilee clip around the pump to hold it onto the hanger.

That's exactly what I done.

 

To be honest, when I bought it, I wasn't even aware that there were different types for the supra?

 

I just ordered it, and fitted it.

 

Being an aftermarket/generic item, I didn't expect it to fit exactly as a stock one would, but it went in fine and worked perfectly

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  • 9 months later...

Can some one explain why you need a restrictor ring? I don't have one on my supra and it runs 3" from the turbos back.. peak boost is about 1.1 bar and hits boost cut, motor is a vvti out of an aristo, cheers!

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Only j spec turbos need a restrictor ring due to the Turbo fans being made from ceramic and not steel (different melting points) smaller Turbo fans as well compared to stock which makes them spool faster then the UK ones so a restrictor ring prevents the Turbo from spooling to fast and melting the ceramic blades

 

Hope this helps (think I got it right)

If not someone will correct me

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Only j spec turbos need a restrictor ring due to the Turbo fans being made from ceramic and not steel (different melting points) smaller Turbo fans as well compared to stock which makes them spool faster then the UK ones so a restrictor ring prevents the Turbo from spooling to fast and melting the ceramic blades

 

Hope this helps (think I got it right)

If not someone will correct me

 

Almost.

 

The Jspec turbos wastegate is not man enough to the task, so if you take away the restriction of the cats, the wastegate can't control the turbo's boost, making it overboost way past it's "safe" limits (around 1.2bar) some Jspec turbos could boost upto 1.8 bar, albeit not very long.

 

The ceramic blades tend to detach from the turbine, chaos and screaming ensue.

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I live in NZ and mine doesn't have any restrictor rings and it boosts fine "custom made 3" so was just wondering what i'm missing

 

Is yours a USDM model? similar to our UK / Euro Spec's they have the steel turbos with larger waste gates, you don't need the restrictor ring.

 

A picture of your engine bay would be able to tell, due to the injectors resistor pack.

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  • 1 year later...
  • 6 months later...

uk steel turbos are stronger than the jap ceramic versions. That being said with your injectors and not knowing your spec list. I would be safe and keep the boost at 1.2 bar (make sure you have a RR)

if you live a little on the wild side then you could up the boost to 1.3 or 1.4 and usually you would be ok but your risk is a bit higher.

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  • 1 year later...
Guys, i am new here, and just wonder, if you do BPU which means removing catalytic converters - is it street legal ?

 

If I recall correctly, you'll still pass an MOT with the second CAT removed, but for BPU and the extra boost, you want to remove the first CAT, which would make it not street legal and you'd need to find a friendly MOT-friend, or swap out that CAT/de-cat pipe at MOT time.

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If you got caught it could get silly, ie your insurance would be i'd imagine invalid as your car

wouldn't pass the mot, or shouldn't pass the mot unless one is fitted, saying that i know someone

who has given his insurance all of his mods, one being the cars de catted and they have insured him

which makes no sense to me if it can't pass the mot

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If I recall correctly, you'll still pass an MOT with the second CAT removed, but for BPU and the extra boost, you want to remove the first CAT, which would make it not street legal and you'd need to find a friendly MOT-friend, or swap out that CAT/de-cat pipe at MOT time.

 

To pass emissions yes your correct will pass with just 2nd cat in , however you need the car very hot to pass at idle, so once your nct/mot passed that should be fine ie road worthy and hence no problems with insurance

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