Does decatting without a remap cause damage?
02 June 2008, 07:01 PM
#1
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Does decatting without a remap cause damage?
I have a 2002 bugeye STI with prodrive pack. If I replace the prodrive sports cat with a downpipe decat will I get more power without the need for a remap? I know I will get the full benifit from a remap but if I get 10 or 20BHP with just the decat i'll be happy for now. I hear conflicting stories about it causing damage without a remap 
02 June 2008, 10:29 PM
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IMHO.....
My bug-eye ran fine for 18 months, but I did fit a catted downpipe to pass the MOT.... no boost problems, or any others !
The car will throw a CEL (Check Engine Light) but it's because the cat efficiency is outside Subaru's "map"... especially if it's missing ! LOL
Mine felt much nicer to drive, and was quicker.
The trouble is it is using the fuel, but not making the power, yours is already up around 300 bhp, so the de-cat will help. A re-map is essential to get all the benefit from this mod !
HTH
DunxC
My bug-eye ran fine for 18 months, but I did fit a catted downpipe to pass the MOT.... no boost problems, or any others !
The car will throw a CEL (Check Engine Light) but it's because the cat efficiency is outside Subaru's "map"... especially if it's missing ! LOL
Mine felt much nicer to drive, and was quicker.
The trouble is it is using the fuel, but not making the power, yours is already up around 300 bhp, so the de-cat will help. A re-map is essential to get all the benefit from this mod !
HTH
DunxC
02 June 2008, 10:34 PM
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A decat will probably do nothing apart from an mot fail, a remap with the cat will see another 20-30hp.
I have a 03 sti with ppp and I have just over 300hp using a road dyno.
I have a 03 sti with ppp and I have just over 300hp using a road dyno.
Last edited by davedipster; 02 June 2008 at 10:38 PM.
02 June 2008, 10:36 PM
#5
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Thanks Dunx. Is this the sort of thing i should be looking at getting?...
SUBARU IMPREZA WRX STi DE CAT DOWNPIPE EXHAUST DECAT on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 03-Jun-08 09:32:37 BST)
Cheers,
Doug
SUBARU IMPREZA WRX STi DE CAT DOWNPIPE EXHAUST DECAT on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 03-Jun-08 09:32:37 BST)
Cheers,
Doug
02 June 2008, 10:47 PM
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I really do think that a remap (£600) will see you better gains (20-30hp) than going for an unnecessarily de-cat. The ppp sports cat is rather good, it flows better than an open pipe.
If fit was me after more power for a 02 stippp I would save up and go for a bigger turbo TD05-20g for example for 370-380hp and supporting mods.
You are looking at £2k in cost though.
dipster
If fit was me after more power for a 02 stippp I would save up and go for a bigger turbo TD05-20g for example for 370-380hp and supporting mods.
You are looking at £2k in cost though.
dipster
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03 June 2008, 12:04 AM
#8
The Bugeye STi can be a be a problem with a full decat as it boost spikes.....there are a lot of threads 5 years ago to do with drilling out the boost restrictor. John Banks posted quite a number of times about this.
You can lose 20 odd BHP if the air temps are warm never mind the sports cat !! summer is coming LOL
Personally I'd keep the sports cat in place and save for a re-map ........look out for group buy's in your area.
Shaun
You can lose 20 odd BHP if the air temps are warm never mind the sports cat !! summer is coming LOL
Personally I'd keep the sports cat in place and save for a re-map ........look out for group buy's in your area.
Shaun
03 June 2008, 11:32 AM
#9
Let me put it this way, my sti bugeye hits 1.5 bar boost UNMAPPED with decat cat back according to my psi3. A full decat will only make this worse. Stick with the sports cat dude, it's the way I want to go.
(Yes I know it's high, I'm saving for a map)
(Yes I know it's high, I'm saving for a map)
04 June 2008, 11:54 AM
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Talk to Simon (JGM) he'll put you on the right course !
HTH
DunxC
Re-map costs more than a de-cat, but do you know a "friendly" MOT tester ?
P.S. If you go for manifold (un-equal length headers) you should get more power and torque, but that adds to the cost !
HTH
DunxC
Re-map costs more than a de-cat, but do you know a "friendly" MOT tester ?
P.S. If you go for manifold (un-equal length headers) you should get more power and torque, but that adds to the cost !
04 June 2008, 03:09 PM
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Also I have just been to see power engineering and they quoted me less for Mapping the car with ecutek and half what JGM quotes for remapps. Have you heard of power engineer? what sort of reputation do they have?
Cheers,
Doug
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