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The mkiv Supra Owners Club

WANTED - 1x Cat removing down pipe


Alex
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Hi there,

 

I need to get a new down pipe to take out the first Cat (probably the Blitz down pipe). Has anyone got one at a good price or does anybody know where I can get one custom made. I'll probably need a boost controller as well so if you have one of those as well let me know.

 

Cheers

 

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Gavin,

 

Rip both cats out - UK cars will STILL only make 15psi tops with both cats out. Both mine and Stu H's cars made the same boost without cats. Spool up time on the turbos is also reduced. It's really not that much of a hassle to get the cats put back on at MOT time.

 

Eric

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It will be interesting to hear of the results if you do.

 

To my mind, it's not worth the bother and bunging in a No2 cat for the MOT is zero hassle for me. But, then again, I've got the tools, the experience, etc.

 

However, to someone like yourself, I can well understand the whole thing may seem rather daunting. In which case the high-flow cat could provide you with a happy medium.  

 

Do you have the web page where the cat is advertised? I'm just wondering about connecting flanges and so forth, and thought maybe I could take a quick look and check it out for you.

 

Yours,

J  

 

 

 

 

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Hi...

 

Your right...it's the hassle factor. There's lots of things in life I would rather pay a few quid to stop worrying about. Having to find someone to put the cat back in each year is a real PITA to me.

 

I have been reading some test results on the hi-flow on the acrchives of the US list. It appears that loss for having the cat fitted was only 1 PSI over the same car with both cats removed.....

 

www.mvpmotorsports.com for the cat info

 

Regards...........Gavin

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Is it a foregone conclusion that you WON'T pass an MOT with both cats off? Mine was MOT'd last Sept, far as I know catless, so I assumed it should be OK. Getting a bit paranoid reading posts about replacing one of them for MOT -  a)I haven't got one b)I really don't want the hassle! Anybody actually passing with no cats?

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Whether the MKIV will pass cat-less is a bit of a moot point. Reportedly, some people have and some haven't. For the MOT I simply replace No.2 cat. Maybe next time I'll find out by leaving the cat off.  

 

One thing I did think of doing, when I eventually get around to changing my engine ECU, is having a fuel and ignition map specifically geared to pass the MOT.

 

It is technically possible to run the normal fuel-map and, at the flick of a hidden switch somewhere, change the fuelling just as you pull up outside the testing station. :)

 

Yours,

J

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I'm a bit confused about Eric's and stu's car only making 15 psi with both cats removed. (Eric did you state your boost as higher during your Ferrari race?)

 

Can anyone explain this,  given that the US boys seem to make big boost with the steel turbos and the J-spec cars have no problem either.

 

thanks .......................Gavin

 

JB ...please move this to technical...thanks

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the UK specs will probably NOT overboost when both cats are removed, they have a bypass pipe of some description (as mentioned in another post round here somewhere), which stops them going totally nuts. So removing both cats and fitting an aftermarket exhaust will more than likely be fine on a UK car, where an import would just boost all over the place.

 

There are also some major differences between the US and UK turbos which may account for this. Im hoping to get photographs of the internals from a UK spec turbo up against an import turbo shortly. You will be surprised at the difference.

 

JB

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smaller internals...on the UK spec. Im trying to get visual proof of it as I dont fancy flying in the face of popular belief by stating they are smaller and then finding they werent.

 

There havent been many UK spec turbos pulled apart so a direct comparison might not have been made before.

 

Now thats a discussion point for everybody...

 

JB

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Yep just to back up what Eric said, we both have UK-spec cars (both manuals actually) and we both had de-cat pipes done and aftermarket exhaust (mine is a Blitz NUR and Eric's is an HKS Hiper), both had TRL FCD fitted.

 

In this condition, Eric's boosted to 15psi and mine to not much more than 13psi.   Even Leon was surprised.    To be honest, knowing know with hindsight how

"conservative" the UK's are in this spec, i probably would have elected to go with a 3" de-cat pipe, rather than the 2.5" pipe.     I was warned off the 3" pipe with overboost stories, but it just shows how differently the UK cars react to these mods.    

Eric's car and mine now have other bits to get the boost up to 17/18psi levels.

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