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The mkiv Supra Owners Club

De-cat, who can do it for me?


jackso11
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Any local garage or even kwik fit can do this. The only ticky part is if a stud snaps when removing the 1st cat, which is why a proper place is best to do this - they'll have all the tools and ramps to fix it.

 

Did you get the other BPU mods done already? From the last thread I thought you hadn't done those yet..

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If you are happy to have a go at this on your own I would just get yourself to halfords and get a set of axle stands. Get the shorter ones so that the stock jack works nicely.

 

As Darryl says the studs from the turbo elbow can be a right royal PITA due to the highest temps being seen there. It is a good idea to absolutely saturate all the nuts/bolts in penetrating fluid (Plus gas, also from halfords) the night before starting the job, so that it can work its magic.

 

A GOOD socket set is necessary. Do not put the star type sockets near the fixings as they will round them off, make sure you use Hex sockets only.

 

Other than that it is a pretty straight forward job, and very rewarding once finished :)

 

Try not to drop the 2nd cat end of the exhaust on your pinkie nail though, hurts like hell!!

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As scott m said, i did exactly that. Was a bit of a pain but once you have the correct tools makes it alot easier. Extension wobble bars, universal joints and good socket set and can't stress enough the use of plus gas (amazing stuff). And it is very rewarding, but hopefully you will have somewhere reasonably warm because you will end up lumping your finger, or hand and hurts alot more when its cold.:D

 

Also make sure you keep hold of your second cat as this willl have to be put back on come mot time.

 

Good luck mate ;)

 

Forgot to add that i managed this last year when my wrist was in plaster :blink:

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Homer, I have the greddy BCC, iridium plugs, boost guage fitted. Just the decat I need doing.

 

I took it into and exhaust and tyre specialist yesterday in lincolnshire as I was at my mums place for the weekend. Got them to switch my tyres from my old wheels to my new ones and asked them to do the exhaust. They said they had a quick look but were too busy at the weekend to do it and could I bring it in the week....unfortunatly I am back in london now so the answer to that was no.

 

I really want to get this done this week or next weekend though :D

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Just to make sure everything is covered, have you replaced the fuel pump? Which grade iridium plugs do you have fitted?

 

Other than that, the above advice is spot on :thumbs:

 

We can all appreciate you're eager, but don't rush into BPU mods, it needs to be done right, or not at all :)

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Sorry to jack thread but i need a quick answer on this one, plus it saves having to make a new thread on it!

 

2.5" second decat will mate to a 3" catback right?

 

The exhaust flanges are the same size correct?

 

they should do as my decats 2.5" and cat backs 3"

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Is a FCD not also needed to get over the 1 bar? Unless his BCC has this built in

 

FCD and BCC are the same thing, though the Greddy is not the best of choices. The Thor one is preferred.

 

Boost cut will occur if approx 1 bar is maintained for more than 3 seconds, so yes, with BPU it is absolutely required.

 

Correct me if im wrong, but will the car not starve from fuel with the standerd pump once the de-cats ar fitted due to gasses being exhausted faster, therefore needing the uprated to pump to deliver the fuel.

 

The stock fuel pump is just about capable of providing fuel for full BPU, however most are 15 years old now so it's best to replace them as a matter of course. The Walbro is uprated and (primarily) a lot cheaper than a stock replacement pump so is a common choice. If the car is UK/export spec it will already have a much higher rated pump installed, but again will likely be very old and past it's best performance.

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Correct me if im wrong, but will the car not starve from fuel with the standerd pump once the de-cats ar fitted due to gasses being exhausted faster, therefore needing the uprated to pump to deliver the fuel.

 

You need the uprated fuel pump because removing the exhaust restriction ups the boost, upping the boost without upping the fuel accordingly leads to detonation buddy :)

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I have both pipes, all gaskets, restrictor ring and had intended on putting them on this weekend but only have the standard jack. Anyone in the london area who can do this for me at a weekend? How much would a garage charge to do this?

 

i know a few normal garages and a good mechanic around the corner from you, morning lane, hes currently doing an na-tt conversion for me.

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You need the uprated fuel pump because removing the exhaust restriction ups the boost, upping the boost without upping the fuel accordingly leads to detonation buddy :)

 

Concerning the pump, that's not completly true mate, the stock jspec pump is fine for 1.2 bar on the stock turbo's. However that is based on it being in as-new condition. The recommendation to replace it is service related rather than performance. As mentioned above, the stock pumps performance at full load may have degraded since being installed all those years ago (and it's sock filter clogged), so it's just best practice to renew the pump and sock. It shouldn't be considered an upgrade, just a safety measure.

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Guest van_damme_supra
FCD and BCC are the same thing, though the Greddy is not the best of choices. The Thor one is preferred.

 

Boost cut will occur if approx 1 bar is maintained for more than 3 seconds, so yes, with BPU it is absolutely required.

 

 

 

The stock fuel pump is just about capable of providing fuel for full BPU, however most are 15 years old now so it's best to replace them as a matter of course. The Walbro is uprated and (primarily) a lot cheaper than a stock replacement pump so is a common choice. If the car is UK/export spec it will already have a much higher rated pump installed, but again will likely be very old and past it's best performance.

 

does this also count for the j-spec n/a? a bigger fuel pump?

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