Ross, I was wondering if you'd have any before and after plots of a PD130 with a decat?
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I'll have a rummage around at work and see what I can find.
Thing is most of the cars with exhausts/decats we do also are remapped.
What I might be able to get is a graph of a remapped PD with a standard exhaust and one with a decat and Milltek, leave it with me
Thing is most of the cars with exhausts/decats we do also are remapped.
What I might be able to get is a graph of a remapped PD with a standard exhaust and one with a decat and Milltek, leave it with me
It would be interesting to find some hard evidence on this subject...Originally posted by techie
What I might be able to get is a graph of a remapped PD with a standard exhaust and one with a decat and Milltek, leave it with me
slim_boy_fat
Guest
I know its not quite the same, but Leo got a full Miltek system including free flow cat on his LCR. It didnt really give much more top end, but it pushed the torque slightly higher and he feels its much less lag.
TDis have the VNT turbos so they are less prone to lag (not saying they dont have it ) than the petrols. VNT is a pretty good set up. Diesels get the benifits because of the lower temps they run than the petrol cars. I doubt that there is much of a difference removing the CAT on tdi engines. At the end of the day its the gearing thats the biggest problem with the tdi. In an attempt to get the very best mpg they fit too high gearing.
Sort the grearing and the car would be fecking rapid..
TDis have the VNT turbos so they are less prone to lag (not saying they dont have it ) than the petrols. VNT is a pretty good set up. Diesels get the benifits because of the lower temps they run than the petrol cars. I doubt that there is much of a difference removing the CAT on tdi engines. At the end of the day its the gearing thats the biggest problem with the tdi. In an attempt to get the very best mpg they fit too high gearing.
Sort the grearing and the car would be fecking rapid..
slim_boy_fat
Guest
Originally posted by driveforward
Thought yours was fecking rapid!?
I get by...
But there could be a new project on the horizon.See how the money is after Christmas.
New project!? PM meOriginally posted by slim_boy_fat
I get by...
See how the money is after Christmas.
slim_boy_fat
Guest
:rotfl:
Bear in mind that Rage's system is a Poweflow and there is no science whatsoever in them, they just drop the old system and make pipes to fit the bottom of the car and chuck a couple of boxes in. I had one too (which I why Rage has one TBH) and when I had mine made up my car felt quicker - maybe that was just the slightly quicker turbo spool-up, maybe it was actually quicker, but it felt different. I didn't get it re-dyno'd (but mine made 189bhp and 306lb/ft on the same rollers on the same day as Rage's signature figures).
A difference in the Powerflows was that my car had 1 more silencer box than Simon's (IIRC), and it was made up by a different fitter, so who knows what else may have been different. Neither car was mapped for the exhaust either; both run the standard Revo TDi map.
Gleistung has several dyno plots of TDi Sports before and after a decat and he was talking a small increase. For me the difference is in the driveability though, because it's less easy to be caught off boost and the shove comes closer to the time you put your foot down without the cat. In any case a chipped TDi can afford to lose some torque in favour of bhp - it might stop them from fading away up the rev range so badly as they do.
Why not get Powerflow just to remove the cat? They charge about £80 and they fit flanges to the cat and to the pipe they use so you can swap it back any time you want - it took me about 10 minutes when I was selling my car.
All turbos need some back pressure to work IIRC, but it isn't a huge amount and the only way the TDi would be different to a petrol engine is if the fancy VNT system had a different need - that I don't know, but Gleistung's posts would suggest the cat is not required.
Fen,
Thanks for that - exactly what I was looking for
I'll do some searches gor Gleistung's dyno plots
Thanks for that - exactly what I was looking for
I'll do some searches gor Gleistung's dyno plots
Just to confuse you some more we've actually done a couple of these.
(see pic I posted)
http://www.seatcupra.net/forums/showthread.php?s=&threadid=26859
Seems to work better keeping cat and just replacing the rest with tubing of at least 60mm diameter..
Will have 2 130 golf's dyno'd in the next couple of weeks. The vnt turbo + cat will muffle the sound so it's not very loud.
(see pic I posted)
http://www.seatcupra.net/forums/showthread.php?s=&threadid=26859
Seems to work better keeping cat and just replacing the rest with tubing of at least 60mm diameter..
Will have 2 130 golf's dyno'd in the next couple of weeks. The vnt turbo + cat will muffle the sound so it's not very loud.
removing the cat will reduce back pressure but it's not the same for a turbo car. the turbo is making a big bit of back pressure by it's self.
removing the CAT on my GT made teh turbo spin up quicker, gave me more topend (significatly felt better above 5500 to 6500rpm) but it did fell as if it lost off boost. also the mpg seemed to get worse also. noise increased **** loads. although I liked the sound I prefer the car the way it is with the normal CAT on
removing the CAT on my GT made teh turbo spin up quicker, gave me more topend (significatly felt better above 5500 to 6500rpm) but it did fell as if it lost off boost. also the mpg seemed to get worse also. noise increased **** loads. although I liked the sound I prefer the car the way it is with the normal CAT on
Don't think it makes that much difference on the TDI's. Another side effect (I haven't seen it personally, but it is known to happen) is a resonance at certain rpms.
Wow! This thread is confusing lol. Just for the record, ive decatted and de-backbox my 306 hdi and i wouldnt say its got any power gain (its also remapped aswell), but it certainly sounds lovely.
And yes, Holy Thread Revival
And yes, Holy Thread Revival
I de-catted mine 6 months ago. Before that i would press the throttle, wait, wait and then a surge of power, wheelspin, wasted power IMO.
After de-cat, smoothed air box, egr disconnected I have a smoother power curve. I hear the turbo spooling up earlier, I hear a crisper snap from the diverter valve.
It helped my engine definitely and feels more responsive. It might affect torque, in that I don't have that huge power surge all at once but have it more spread out and earlier, so this would increase bhp, IMO.
I did a lot of research before I did the decat and I'm happy with it.
After de-cat, smoothed air box, egr disconnected I have a smoother power curve. I hear the turbo spooling up earlier, I hear a crisper snap from the diverter valve.
It helped my engine definitely and feels more responsive. It might affect torque, in that I don't have that huge power surge all at once but have it more spread out and earlier, so this would increase bhp, IMO.
I did a lot of research before I did the decat and I'm happy with it.
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