Downpipe/de-cat

[EOD]

Hello all. I am new to the forum and already I have a question. I have a MK 1 V300 and I am trying to BPU the car. So far I have done everything except for add a down pipe. I am having trouble finding one when doing searches for Aristo parts. If any of you have any brand names, model numbers, etc. that would be a big help. Maybe this is a stupid question, but would the downpipe intended for a Supra work? I realize that they are the same engine, but I am not sure if there would be a difference because of the different bodies (possibly meaning different bends and lengths of the pipe). Any help that you all can offer would be greatly appreciated.

[Monster-Mat]

have you done everything to protect the Turbos, from High boost problems.

you could use Supra stuff and Modify it.....it was to get it all to fit in My IS200

[EOD]

Thanks for the help, at least now I know that it is possible to use Supra parts. As for protecting the turbos, I am still debating whether I should only remove the #2 Cat, or remove both and use a 1.2 bar restrictor ring. I am not sure which is better, but it seems that they both would ulitmately have the same result. Here is a disclamer by TDI that elaborates more on what I was saying.

note: We do not reccomend removal of the 1st catalyst (on vehicles using stock turbos) due not only to the legality issue but also the fact that the Twin Turbo Supra uses the cats as a method of boost control. Removal of both cats can lead to excessive boost levels and/or 'boost creep' (especially on Jap models) due to the vehicle being unable to control exhaust flow. Cat removal pipes are available that can sometimes keep boost pressures reasonably low but they need to be made from a relatively small diameter pipe (2.5") to still present a restriction to flow. In our opinon this is pointless and retaining the stock 1st cat and using the very large (3") HKS front pipe usually achieves a similar result at a cheaper cost, whilst still keeping the vehicle legal and guaranteeing that boost levels remain safe for the engine.

Based on this statement, it would seem that leaving the #1 cat in place is a good idea. However, other research suggest that removing both would be more benificial. Do you have any ideas or inputs? I also have a boost controller, which should allow me to prevent overboosting....right? Or have I completely over shot this one.

[Aristopheles]

Get them both out and slap a restrictor ring in there - most common practice on the Supra, and it works just fine. As for having a boost controller, who told you to buy that? I'm pointing no fingers, but it was a waste of time and money - the UK version of the 2JZ-GTE engine needs a boost controller to raise boost at BPU, but seeing as the JDM engine uses the cats to control boost, once one or both of these is out, boost will rise automatically. You'll need the aforementioned restrictor if both cats are junked - though you already know this - to restrict boost to the 'safe' level of 1.2bar. Boost controllers can only raise boost, not lower it, so it won't save you if you start overboosting.

[EOD]

Thanks a lot for the advice. I have been leaning more towards taking out both cats. Cheers. :D