JDM Supra Full Decat...

This has bugged me for ages and yet i have not seen any information at why this is.

JDM's supra's when decatted require a Restrictor ring to keep the boost down, as the JDM wastegates are easily over whelmed. So why is it that there are so many JDM supra's that are full decat and no ring and boost to around 0.9-1.1 bar and require an EBC to increase boost there on further, similar to UK cars.

To name a few, Nic, Kosmic dont need a restrictor ring and both are fully decatted.

So why is this the case?

Stop ducking this question you sods:D

its a mystery

could it be to do with age?

i de catted mine with ring a while ago, but didnt feel any significant power increase.

not sure of boost as gauge didnt get fitted, will check when it does,

mines a facelift, is niks/cosmics?

if so it could be another thing mr T tweaked wiv the post 96's

if so it could be another thing mr T tweaked wiv the post 96's

Mines March 97, but pre VVTi, and I needed a restrictor ring

i thought the same but im beginning to think it may be down to a sticky/jammed wastegate. it would be interesting to know how many others have the same on the JDMs

mine boosts to 0.9 with ring and 1.1 without ring, my exhaust (make unknown) is 2.5 inch bore which i am sure makes a difference

Mines March 97, but pre VVTi, and I needed a restrictor ring

so's mine! they might have been production line neighbours!

mines a pre-vvti. has the tanabe which has huge straight piping and probably one of the most unrestrictive exhaust out there. im running 2.5" decats which may be the bottleneck?! without the ring i can just about hit fuel cut at 1.0bar on a cold day but usually about 0.9-0.95 bar

Kosmic let me know when you have fitted the EBC:)

My pre-vvti makes about 1.4-1.5 bar without a restrictor ring.

I have 3" zorst piping