The place to "speak geek"
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Rich H
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by Rich H » Fri Aug 22, 2008 8:33 am
Fitted one last night with the help of the Cadets. Most of them didn't know how to use a ratchet or follow simple instructions but we got there in the end. (Sadly the 8mm undertray bolts seem to have stripped their threads, so at some point will need helicoiling

)
The pickup appears to be significantly quicker, so much so that I have had to
apparently adjust my dowshift blip technique as I was getting more revs from the 'blip' than normally expected (I'm usually pretty much spot on)
Now is this a perception problem (as I'm subconsiously judging it on the noise) or can a decat really make that much difference?
Sounds good for now, but the 3 months countdown to me getting sick of it and taking it off again has started...

1994 Lotus Esprit S4 - Work in progress
1980 Porsche 924 Turbo - Funky Interior Spec
2004 Smart Roadster Coupe - Hers
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mwmackenzie
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by mwmackenzie » Fri Aug 22, 2008 8:49 am
I have one and a 4-2-1 manifold to fit to mine so interested in what folk think the difference will be? is it just the noise as you say or is it actually a better pickup??? Is it much louder?
Mark
Mark MacKenzie
BMW Z4 3.0si, [R14 MMK] To be Ring ready soon
Merc family hack [R4 MMK] 85% MacKenzie'd Family Spec
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BiggestNizzy
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Contact:
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by BiggestNizzy » Fri Aug 22, 2008 8:56 am
mwmackenzie wrote:I have one and a 4-2-1 manifold to fit to mine so interested in what folk think the difference will be? is it just the noise as you say or is it actually a better pickup??? Is it much louder?
Mark
I have both on mine and I found the de-cat made no difference, the manifold however was night and day!
Sent from my ZX SPECTRUM +2A
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Rich H
- Posts: 9314
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by Rich H » Fri Aug 22, 2008 9:05 am
Manifold definatly deagged the torque back down form 5krpm.
De-cat has made a "percieved" difference certainly. Jsut wondered if there was any fact behind it.
How easy should it be to see thru a Cat? Mine was pretty fooked (Most of it fell apart long before it was fitted) but you can barely see thru the matrix.
1994 Lotus Esprit S4 - Work in progress
1980 Porsche 924 Turbo - Funky Interior Spec
2004 Smart Roadster Coupe - Hers
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Matelotman
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by Matelotman » Fri Aug 22, 2008 10:11 am
I've had my car just over a year now and the de-cat has been off and on about 5 times now..... I don't know about performance but the car sounds better (read louder) for about 2 days before the bleeding ear syndrome gets annoying and I end up going back to the relative tranquility of life with a cat. The cat is now here to stay.
Elise S1 B&C 140 - long time ago now
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Rich H
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by Rich H » Fri Aug 22, 2008 10:25 am
I had one a couple of years ago so I have been through this loop before...!
It was free anyway, so will be passed on to the next victim, just like the last one...

1994 Lotus Esprit S4 - Work in progress
1980 Porsche 924 Turbo - Funky Interior Spec
2004 Smart Roadster Coupe - Hers
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tut
- Barefoot Ninja
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by tut » Fri Aug 22, 2008 2:51 pm
A de-cat does make a difference on the RR, maybe 2-3hp, because you have a straight through path with no resrictions, but that is not something that you will feel on the road. It will sound louder, which can be confused with feeling faster.
However it does save a few kgs which is always useful, but you will put out more fumes which will piss off Robin if he is behind you, but I am all for global warming if it will heat up Scotland, so I do my bit and leave it off.
tut
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ABZ-Elise
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by ABZ-Elise » Fri Aug 22, 2008 3:55 pm
I fitted a de-cat pipe and a 56mm throttle body at the same time. I did notice a differance but I think it was mainly due to the throttle body as when I took my old cat off I found there was nothing inside it, i should have just kept it on so it at least looked like I had a cat

I kinda want to know where the insides of it went tho

1999 S1 Elise - For Sale
2003 E46 M3 - Sold
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mwmackenzie
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by mwmackenzie » Fri Aug 22, 2008 4:02 pm
So the 56mm TB makes a difference??? How much?
Mark
Mark MacKenzie
BMW Z4 3.0si, [R14 MMK] To be Ring ready soon
Merc family hack [R4 MMK] 85% MacKenzie'd Family Spec
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Shug
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by Shug » Fri Aug 22, 2008 5:00 pm
The only difference it makes is in response, as you'll be opening a bigger gap with smaller throttle openings. Jury is still out AFAIK if a 56mm body will make the MEMS run it lean, but there are plenty of 52mm ones out there with no problems. If you've got a standard placcy body on it, then swap away, but if you're swapping from an alloy body, it's not massively cost effective...
2010 Honda VFR1200F
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mwmackenzie
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by mwmackenzie » Fri Aug 22, 2008 5:08 pm
Mine is alloy but I have no idea what size??... I'll leave it alone me thinks...
Mark
Mark MacKenzie
BMW Z4 3.0si, [R14 MMK] To be Ring ready soon
Merc family hack [R4 MMK] 85% MacKenzie'd Family Spec