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The mkiv Supra Owners Club

Removing both Cats with stock exhaust


BigRoy

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Hi guys, I know some of you have done this so a couple of questions. What power gain/driveability would you expect by replacing the stock exhaust with no cats with say a Nur Spec? Is it worth it in terms of gain versus noise? If I just remove the cats and leave stock, any idea on power increase/driveability I might expect? :D

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Best, cheapest mod for the power gains.

 

Benefits:

 

1. Turbos spool quicker, better throttle response

2. Luverly noise. Not too loud in the cockpit.

3. Goes fast as f*ck

 

Drwabacks:

 

1. Tricky at MOT time (emissions)

2. Need to look at buying new plugs, boost restrictor plate, boost gauge and fuel cut defenser.

 

:flame Dev

 

Justin

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You shouldn't need a restrictor ring on a UK car as they don't suffer from 'boost creep' in the way j-spec models do.

 

Definitely worth doing as you will be more than pleased with the results.

No massive increase in noise unless you remove the baffle from the Nur Spec..........as I have done:D

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I lost both cats and put a Hiper on and moved upto 0.91 Bar max in my UK :D (I did have a VFCC/FCD fitted at the time too)

 

Well worth the ££

 

Just got to keep one of the moggies for that annual PITA

 

You do not need to go for a noisy back box if you are not into that !

 

If you left the stock back box on then you are leaving in a restriction so, the gain will not be as good I guess......

 

both cats out and a aftermarket back box and you WILL be :D for weeks - Oh yes.

 

Mind you, you might hit fuel cut on cold days so a FCD/VFCC might be in order too.

 

Boost gauge is a must! as no two cars are the same.

 

HTH

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OK. So once i've done the exhaust, FCD, filter and managed to plumb in my DSBC-iD out of the old ZX, what is a sensible level to run it at 1.2bar? Or can I go higher. I don't mind using Optimax or octane booster if I really have too. Also has anyone got the Blitz DSBC and power iD in their car, if so where have you mounted them? :blink:

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You used the word sensible, Hmmmm 1.2 - 1.25bar IMO

 

I think some, maybe JB runs 1.3 on his UK ??

 

I guess since the limit of the MAF (A little out of my league here now) is between 18-19 psi then I would assume that you have to think about your fuelling if going over the 1.25bar mark ?

 

You also got to think about how long you want the turbos to last, give them more stick and it's natural that they will not last as long. (Turbo timer helps a little here)

 

As for location, I have seen a few with the to ID units taking up the space of 1 DIN, just below the single DIN headunit - assuming that you have replaced the stock Head unit ?

 

I have a pic somewhere....I'll have a look.

 

Anyway, I hope this helps.

 

I'm sure that someone will shoot me down if I am talking complete cr@p.

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Roy

Be aware that UK cars DO NOT get the same gain as J spec from the Cat remoavl.

I had both cats out and Nur Spec fitted with FCD at same time on my UK.

This only produced .8 bar max. OK it felt quicker and spooled a bit quicker but was not the giant leap i was hoping for.

The same day i bit the bullet and had a Blitz DSBC fitted, BIG smiles all round.....

So you may need your BC fitted at the same time before you get near your 1.2 bar which feels great by the way.....:flame Dev

The above is all from personal experience and may not be the samer for all UK specs.:innocent:

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