Sports Exhaust.
Discussion
I know this has been covered on a few occasions, but I wanted your opinions on which one to go for, and the 'search' facility keeps playing up.
I currently have a sports exhaust, but the baffles are loose due to speed bumps. My main concern/question is the sound. I want the sound to be similar to as it is now. Love the deep base to it. The sports exhaust currently on is the 'cheaper' one according to Joolz. Its not the JP system. I dont want to 'decat' because in my opinion its too loud. I've heard that the JP system will be quieter than the one i've got.
I was bidding on one on ebay, but lost it. It looks similar (the brackets) to mine I have.
http://cgi.ebay.co.uk/ws/eBayISAPI.dl
What do you think.
I currently have a sports exhaust, but the baffles are loose due to speed bumps. My main concern/question is the sound. I want the sound to be similar to as it is now. Love the deep base to it. The sports exhaust currently on is the 'cheaper' one according to Joolz. Its not the JP system. I dont want to 'decat' because in my opinion its too loud. I've heard that the JP system will be quieter than the one i've got.
I was bidding on one on ebay, but lost it. It looks similar (the brackets) to mine I have.
http://cgi.ebay.co.uk/ws/eBayISAPI.dl
What do you think.
Edited by kojak on Monday 19th February 17:41
Interesting comments about the big bore, the guy that's currently making my system said that 2" pipe is suitable for upto 400bhp, he did quote flow but I glazed over a bit at that point. 
So, it looks like 3" pipes may mainly for noise. I'm having my cats welded together and pipes brought closer together so that there's more air flowaround them and hopefully lessen the chances of another fire when the cats are on.
The back boxes on mine are having the centres offset so that they sit tighter to the bodywork. They will alsoe be repackable with the option of an internal additional silencer.
The rear tips will be removable with a flange so that I can bolt on track day cans as and when they're needed.
Small skid plates are being welded onto the bottom of the cans to lessen any damage.
Hopefully I've covered all the bases.
Tim
So, it looks like 3" pipes may mainly for noise. I'm having my cats welded together and pipes brought closer together so that there's more air flowaround them and hopefully lessen the chances of another fire when the cats are on. The back boxes on mine are having the centres offset so that they sit tighter to the bodywork. They will alsoe be repackable with the option of an internal additional silencer.
The rear tips will be removable with a flange so that I can bolt on track day cans as and when they're needed.
Small skid plates are being welded onto the bottom of the cans to lessen any damage.
Hopefully I've covered all the bases.
Tim
TT Tim said:
Interesting comments about the big bore, the guy that's currently making my system said that 2" pipe is suitable for upto 400bhp, he did quote flow but I glazed over a bit at that point. So, it looks like 3" pipes may mainly for noise.
So, it looks like 3" pipes may mainly for noise. If he meant 2" for the whole system is suitable for upto 400bhp then he may be right, but this would cause a lot more restriction and alot of mapping would be required to get the engine to 400bhp. Therefore I would not recommend going for this size as it is a step backwards.
A car that runs 400bhp on a std exhaust system (2 1/8th"
will run more bhp and torque with a larger diameter system (either 2 1/4" or 2 1/2", the added bonus is that the sound is much bassier. What size are you going for? I would guess that if you are having a bespoke system then 2 1/4" or 2 1/2" is the way to go.
Jules.
Really pleased with the result. It sounds slightly louder than before, but is deeper and clearer. Well pleased. Thx Tim 
Have you got decats as well? I am going for the Act Manifolds and there big bore exhaust system, want to retain the decats (may switch to linked) but not sure whether to have the extra silencers or not. I currently have decats and sports tailpipes, don't mind the volume most of the time but is a bit raspy for my liking.
The original announcement for the ACT manifolds says that the diameter of the main pipes is 57mm. Not an exact match, but about 2.25" in old money. Don't know whether that's external or internal - or if it's different to the standard manifolds.
That being the case, however, how can there be any benefit in having pipes of a larger diameter (e.g. 2.5" ) downstream if the gases have to fit through a pipe of this dimension first?
That being the case, however, how can there be any benefit in having pipes of a larger diameter (e.g. 2.5" ) downstream if the gases have to fit through a pipe of this dimension first?
Edited by daver on Monday 19th March 06:48
cerbfan said:
Have you got decats as well? I am going for the Act Manifolds and there big bore exhaust system, want to retain the decats (may switch to linked) but not sure whether to have the extra silencers or not. I currently have decats and sports tailpipes, don't mind the volume most of the time but is a bit raspy for my liking.
Sorry for the delay. No I didnt go for decats too. In my opinion, it would have been too loud.
I'm perusing over sports exhausts just now, but not sure which one will make my 4.5 sound bassier. You can hardly hear the (standard) exhaust from the cabin under acceleration, it needs beefing up, but not to the point where it screams boy racer 
Has anyone fitted a big bore to their 4.5?
Has anyone fitted a big bore to their 4.5?
daver said:
The original announcement for the ACT manifolds says that the diameter of the main pipes is 57mm. Not an exact match, but about 2.25" in old money. Don't know whether that's external or internal - or if it's different to the standard manifolds.
That being the case, however, how can there be any benefit in having pipes of a larger diameter (e.g. 2.5" ) downstream if the gases have to fit through a pipe of this dimension first?
That being the case, however, how can there be any benefit in having pipes of a larger diameter (e.g. 2.5" ) downstream if the gases have to fit through a pipe of this dimension first?
Edited by daver on Monday 19th March 06:48
Yes there is still a benefit, pressure drop across an orifice is dependent on the volume i.e. Area x the length, so as a pressure drop is what we want in this case (reduced back pressure) we want both the area and length to be as large as possible while still retaining some back pressure. Therefore although the area is smaller in the manifold the fact that it is for only a short length is much better than it being that diameter for the whole length of the exhaust.
Just had the JP exhaust system fitted to the Cerb - I never heard it first myself but it originally had the two main sports silencers plus cherry bomb stylie silencers fitted in the centre section - it was so f***ing loud when run on Austec's rollers that some guy working in the office building on the opposite side of the road came across complaining that he couldn't hear people talking to him on the phone 
Tim at ACT added extra silencers into the bigger bore tail pipes which has quietened it down somewhat although it's still pretty loud under heavy load That said it's definately much quieter than the original sports system at motorway cruising speeds (on a fairly light throttle) which was the principal reason for changing it in the first place. Any long runs made my ears bleed before
Tim at ACT added extra silencers into the bigger bore tail pipes which has quietened it down somewhat although it's still pretty loud under heavy load That said it's definately much quieter than the original sports system at motorway cruising speeds (on a fairly light throttle) which was the principal reason for changing it in the first place. Any long runs made my ears bleed before keithyboy said:
Just had the JP exhaust system fitted to the Cerb - I never heard it first myself but it originally had the two main sports silencers plus cherry bomb stylie silencers fitted in the centre section - it was so f***ing loud when run on Austec's rollers that some guy working in the office building on the opposite side of the road came across complaining that he couldn't hear people talking to him on the phone Tim at ACT added extra silencers into the bigger bore tail pipes which has quietened it down somewhat although it's still pretty loud under heavy load That said it's definately much quieter than the original sports system at motorway cruising speeds (on a fairly light throttle) which was the principal reason for changing it in the first place. Any long runs made my ears bleed before
Tim at ACT added extra silencers into the bigger bore tail pipes which has quietened it down somewhat although it's still pretty loud under heavy load That said it's definately much quieter than the original sports system at motorway cruising speeds (on a fairly light throttle) which was the principal reason for changing it in the first place. Any long runs made my ears bleed before Sounds perfect mate in tweaked mode, quiet on the cruise and nice and fruity on the gas. Really looking forward to getting mine fitted now.
Here's a gentle run around an airfield last week.
Quite pleased with the sound of my custom made PowerSpeed exhaust.
The mic was on the passenger seat btw
www.tvrspeedchampionship.co.uk/Files/2007_Video/01_NorthWeald_180307/NorthWeald07.mov
WARNING, it's an 18Mb file
Tim
PS: No comments about short shifting, crap lines or backing off too early please. It's the first time I've driven the car since last October! Well in the dry anyway.
Quite pleased with the sound of my custom made PowerSpeed exhaust.
The mic was on the passenger seat btw
www.tvrspeedchampionship.co.uk/Files/2007_Video/01_NorthWeald_180307/NorthWeald07.mov
WARNING, it's an 18Mb file
Tim
PS: No comments about short shifting, crap lines or backing off too early please. It's the first time I've driven the car since last October! Well in the dry anyway.
if u want to decat but stay gorgeously silent ..how do you do this...i have two little kids and the only way the missus will let them in the car is with the silence.,...how do i decat and stay silent...i have been told the standard back box will keep it at reasonalble levels but in reality i am looking for a really quiet system.whay do u guys reckon
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