Exhausts - More Power
Discussion
30/40% bhp is totally bollocks. You might get a few bhp removing the cats, but the cats truly are performance free flowing versions. You do get better unloaded throttle response though. Bypassing the rear silencer would probably be similar.
The factory notes that most sports exhaust conversion can actually reduce power - if not at the top end, then certainly the mid range - I can definitely believe this having seen some dyno graphs.
The only way of getting significantly more power would probably be to redesign the front manifold, but the main problem is a lack of space!
Note - if you really WERE able to make a better exhaust system, you'd need to be able to change the ignition/fuelling anyway, which you can't without a lot of hassle.
It will sound better though!
danny
The factory notes that most sports exhaust conversion can actually reduce power - if not at the top end, then certainly the mid range - I can definitely believe this having seen some dyno graphs.
The only way of getting significantly more power would probably be to redesign the front manifold, but the main problem is a lack of space!
Note - if you really WERE able to make a better exhaust system, you'd need to be able to change the ignition/fuelling anyway, which you can't without a lot of hassle.
It will sound better though!
danny
removing the cats will cause the car to fail an MOT but fairly straight forward to refit at MOT time. One point i have heard is that the police are clamping down with large fines upto £5000 for this so beware.
BHP gains for cat removal is only about 5bhp but makes the car sound more harsh IMO. Rear silencers make the car sound more intense again IMO and do apparently reduce mid range power not that you should notice with so much power available. I have the Peninsula silencers fitted to mine and they are very good but would recomend going to a track day and listening to several to find out what you like.
BHP gains for cat removal is only about 5bhp but makes the car sound more harsh IMO. Rear silencers make the car sound more intense again IMO and do apparently reduce mid range power not that you should notice with so much power available. I have the Peninsula silencers fitted to mine and they are very good but would recomend going to a track day and listening to several to find out what you like.
In my experience sports exhausts don't increase power.
Removing the cats will, but not those amounts. There is a definate increase in sustained acceleration nearer the rev limit than without, and there is much more of a kick at 4-5000 rpm. Noise is amazing. Re-fitting them at MOT time is simple for any garage.
From my knowledge of the law i.e. my dads a senior traffic cop, it's not illegal to remove the cat's but if a local government office shoves a meter up your pipe and the emissions are too high, you can be fined or your car can be removed from the road until it is fixed. Only a few councils are now doing this as too many of them have lost court battles by fining people who's car's have just passed an MOT. Don't be confused if the Police seem to be doing emission tests, it's the council really, but the police are the the only people legally who can pull you over.
Sorry - I didn't mean to waffle so much.
Removing the cats will, but not those amounts. There is a definate increase in sustained acceleration nearer the rev limit than without, and there is much more of a kick at 4-5000 rpm. Noise is amazing. Re-fitting them at MOT time is simple for any garage.
From my knowledge of the law i.e. my dads a senior traffic cop, it's not illegal to remove the cat's but if a local government office shoves a meter up your pipe and the emissions are too high, you can be fined or your car can be removed from the road until it is fixed. Only a few councils are now doing this as too many of them have lost court battles by fining people who's car's have just passed an MOT. Don't be confused if the Police seem to be doing emission tests, it's the council really, but the police are the the only people legally who can pull you over.
Sorry - I didn't mean to waffle so much.
Right this is pretty straightforward.
Step 1, add sports exhaust and remove cats
Step 2, get somebody in the know to set the AJP to its second (alternate?) map which tells it there are no cats and therefore no need to control emmissions due to the prescence of cats.
I heard this from SHG and TVRS and believe it to be true. Especially as a friend had his 4.5LW done at Peninsular and boy does it fly.
Bennno
Step 1, add sports exhaust and remove cats
Step 2, get somebody in the know to set the AJP to its second (alternate?) map which tells it there are no cats and therefore no need to control emmissions due to the prescence of cats.
I heard this from SHG and TVRS and believe it to be true. Especially as a friend had his 4.5LW done at Peninsular and boy does it fly.
Bennno
Benno, this sounds like bollocks. Some variants of the 941 ECU support an alternate map, which the Red Rose cars use to hold the 95 and 97 maps - perhaps where your rumour came from? Certainly the standard one doesn't just have this hidden alternate decat map, and even if it did, how would you select it?
There ARE however various versions of the map chip, some of which are alleged to have been done for decat 4.5's. Since each engine is different though, different maps will suit better. Some cars just don't run happily without cats either. The way the best chip is selected is simply by trying them in order apparently!
If you REALLY want to remap it, it's probably easier to stick on another engine management in parallel with the MBE.
danny
There ARE however various versions of the map chip, some of which are alleged to have been done for decat 4.5's. Since each engine is different though, different maps will suit better. Some cars just don't run happily without cats either. The way the best chip is selected is simply by trying them in order apparently!
If you REALLY want to remap it, it's probably easier to stick on another engine management in parallel with the MBE.
danny
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