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Thanks Japper,
I'll look into that.

But it just looks like a straight pipe with a few small bends...... i think my exhaust guy can do the same here.
 

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Hi Roland - Q for you -

What about a turbo downpipe? - I've seen Alta have done one - therefore allowing a full turbo back exhaust - I can see there real gains to be had from from your GTT cat modification - but - not sure how much there is to be gotten from the rest of the system on top of this and the JCW kit without looking for ECU changes.

I've driven a few R56 JCWs now - and they are truly awesome - properly quick throughout the whole rev range - maybe graphs will show that the output is even being restricted - ie totally flat torque curve.
 

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Hi, I have had the dump Pipe done and it definitely makes a difference. I'd had the JCW kit fitted some 6 months ago and although i was disappointed with the difference that made to the "feel", I then fitted an Alta full pipe kit & IC and that made a big difference.

I was then doubtful if the GTT mod would make much difference. However, i went ahead and had the Pre-Cat removed and the dump pipe refitted to the JCW exhaust and it made a substantial difference to top end power. The IC helped down the bottom end with a big torque increase and the GTT Cat mod is worth it for a fuller, more powerful rev range to redline.

I have a mate who had a full 3" system from the turbo back fitted and did not go with the JCW kit. Whilst he has had significant power gains (I think 128kw at the wheels on a dyno) and he has subsequently fitted the same pipe and IC Alta package as me (Dyno was pre-fitment of that stuff) he says that my MCS feels like it still pulls better down low than his. We can only put it down to the JCW mapping and perhaps the new manifold they developed between the block and turbo.

Before the GTT mod was fitted i dynoed at 138kw and i estimate another 8-12 kw's were gained from the mod. Although i fitted the Alta CAI at around the same time, i could only put that mod down to 2-4KW of the improvement.

Hope this helps.Its a worthwhile mod, especially if you like to take it to the redline :D
 

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Discussion Starter #67
Thanks guys we put our stock car on the dyno and got 175bhp then with GTT stealth cat + GTT Boost DeMuff pipe and got exactly 190bhp. The RR did not simulate the actual boost you get on the road, so in the real world I think the difference is even greater. I have the graphs somewhere.
 

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Thanks guys we put our stock car on the dyno and got 175bhp then with GTT stealth cat + GTT Boost DeMuff pipe and got exactly 190bhp. The RR did not simulate the actual boost you get on the road, so in the real world I think the difference is even greater. I have the graphs somewhere.
Going by the "seat of the pants" dyno, those figures do not surprise me with both mods. I believe the second DeMuff would be worth a few HP as well.
 

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De-cat?

Roland:
What about a full de-cat?! Any ideas is it possible? i undertstand it wont pass the MOT but most r56 cooper s have 2/3 years before thats a worry. How would the set up work in regards to the sensors, would you just have to tie them under the car. And warning lights? Do you know would there be any can it be done? Thanks
 

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Roland, are you still offering this conversion?

If so are the prices still current?

How about a group buy?

And can someone clear something up for me. This mod is essentially the same as the Miltek downpipe as far as I can see. But does anybody have any figures for how many cells the Miltek cat has, and the same for this conversion?
 

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Roland, are you still offering this conversion?

If so are the prices still current?

How about a group buy?

And can someone clear something up for me. This mod is essentially the same as the Miltek downpipe as far as I can see. But does anybody have any figures for how many cells the Miltek cat has, and the same for this conversion?

I'm not 100% sure but believe:

The OEM DP has a 400CPI + 200CPI cats. GTT remove the 400 CPI cat.
Milltek has a 200CPI cat.

So in essence both the same i belive.

GGR ( Graham Goode Racing ) DP cat has a 100CPI cat.

If anyone wants it, i have a spare OEM DP / cat for sale:D
 

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Discussion Starter #74
Hi Guys, yes we can do a group buy on this. Min 5 people......£50 dep up front ........Normal price £199+vat ( to mod your unit / exchange). M2 Group Buy price ....£149+vat !!
Please post here if your up for it, and tel 01258 455545 to pay deposit. Its approx 2-3 day turnaround for units sent down to mod. Please phone if you prefer us remove /refit to car aswell.
Best regards Roland GTT :smile:
 

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Roland, just a few questions. :)

£149 for a group buy sounds very good to me - how much would it be if people could not exhange their units - due to time / having the car off the road etc?

Also, did you ever put it through an MOT - if so, I presume it passed?
 

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Discussion Starter #76
Hi, yes it passed all MOT emmisions with good headroom to spare. I did put the figures up on M2 at the time...They were certainly cleaner than most 'sports cats'.
We can sell these with surcharge, refundable on return of a good stock ubit. But the surcharge has to be the replacement cost from BMW ..IIRC around £400
 

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£400?! Jesus that's steep. :(

I am very interested in one of these, but at £171.35 (inc VAT) another £400 as a surcharge means I am not going to be able to afford one - I realise that this is refunded, however the money will still be out of my hands for a period of time while I get the new cat fitted and the old one removed to post back to you.

Fitting at GTT is not an option either as you are miles from Newcastle. :(
 

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is this product still available Roland? if so whats the price nowadays :)
 
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I didn't get it from Roland as i am in Aust, but going from the description he gave i had a local provider make the changes to the cat and i have never had a light come on in 2.5 years. The difference in driving is immediate with extra raspy noise emanating from the rear. I already had the JCW tuning kit fitted so it already sounded quite good. As the system got older and more track days went by it started to sound quite like the Challenge cars. As far as power goes, I had (as mentioned earlier) the JCW TK, plus i had already fitted the ALTA IC. Best bang for buck is he IC, over the JCW KIT, but that really added a lot of low down, push you back torque and some power gains. The GTT Stealth seemed to add more top end free revving power. Its a nice balance between the IC and the GTT mods they seem to balance out the torque-Power curves. Hope my opinion and experience helps.
PS the Unichip after both mods was excellent as well.
 
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