exhaust noise!
Discussion
Thinking about having either Offord's cherry bomb's fitted to the exhaust of my fairly standard 96 Griff 500 or having it sleeved. I like to do track days and don't want the hassle of being over track noise limits. I also do some touring in the summer and don't want to loose the comfortable cruising noise levels. Any feedback would be appriciated.
Just my thoughts on this, might not be correct but,
If you fit an aftermarket system that is a bit noisy it’s not illegal, but if you modify a standard system to be noisy it is, or can be.
If you buy a second system, you can swap back and forth as the mood takes you.
Been thinking exactly the same as you,
Cheers,
Simon.
If you fit an aftermarket system that is a bit noisy it’s not illegal, but if you modify a standard system to be noisy it is, or can be.
If you buy a second system, you can swap back and forth as the mood takes you.
Been thinking exactly the same as you,
Cheers,
Simon.
jacjac said:
Thinking about having either Offord's cherry bomb's fitted to the exhaust of my fairly standard 96 Griff 500 or having it sleeved. I like to do track days and don't want the hassle of being over track noise limits. I also do some touring in the summer and don't want to loose the comfortable cruising noise levels. Any feedback would be appriciated.
Are you still running with the precats fitted ?If yes then remove them first of all
Still have pre cats fitted and the standard main cat. I do a few minor mods myself but removing manifolds and pre-cats is beyond me. The cherry bombs or sleeving are reasonable value. With my limited knowledge what effect do these options have on back pressure to the engine? I do not want to loose any power!
jacjac said:
Still have pre cats fitted and the standard main cat. I do a few minor mods myself but removing manifolds and pre-cats is beyond me. The cherry bombs or sleeving are reasonable value. With my limited knowledge what effect do these options have on back pressure to the engine? I do not want to loose any power!
I have no reasons to keep the precats in place and plenty to remove them.1 It is not required by law to have them fitted in this country and will not effect your mot.
2 Under bonnet temperature will be reduced dramatically once removed
3 you will gain between three to five hp as a result of getting rid of them.
4 the exhaust note will be improved but not too loud.
If i were in your shoes i would have the precats removed and the back box sleeved ask them for a price to do both
Trust me you will not regret it 
Edit to add i found no issues with back pressure and would not fit cones in the manifolds ether
Edited by Pasco on Tuesday 15th April 12:04
I had a set of ACT decat manifolds and a V8 Enhancements Y piece fitted recently. I recommend both. The rest of my system is standard.
This was put in because I was having other work done at the time and they were coming out. It seemed a shame to put the standard bits back.
Clive mentioned his new manifolds, but hadn't tested them. Even he didn't know how good they were at that time.
If I were doing it again then I would have waited and got the new manifolds. Unless you have a pressing need because something needs fixing, wait and get the new V8 Enhancements manifolds.
If you do go for the decat and Y piece then you will get a great note that sounds quieter, but isn't. Mine is 110db at 4000 rpm. However, the car has a big cam and a few other modifications.
You should aim for quality of sound but not quantity as it makes track days a problem.
This was put in because I was having other work done at the time and they were coming out. It seemed a shame to put the standard bits back.
Clive mentioned his new manifolds, but hadn't tested them. Even he didn't know how good they were at that time.
If I were doing it again then I would have waited and got the new manifolds. Unless you have a pressing need because something needs fixing, wait and get the new V8 Enhancements manifolds.
If you do go for the decat and Y piece then you will get a great note that sounds quieter, but isn't. Mine is 110db at 4000 rpm. However, the car has a big cam and a few other modifications.
You should aim for quality of sound but not quantity as it makes track days a problem.
I too like Fester have Clive's main cat replacement pipe which is a super bit of kit
To be honest i would have thought Clive's new tuned manifold masterpiece would only be suitable for highly modded cars or even track cars the likes of them that race in the Tuscan challenge rather than a bloke who wants to make his car sound a little louder and trust me they make Clive's car sound like a Ferrari 360
Get the precats removed i can not over stress this point enough
To be honest i would have thought Clive's new tuned manifold masterpiece would only be suitable for highly modded cars or even track cars the likes of them that race in the Tuscan challenge rather than a bloke who wants to make his car sound a little louder and trust me they make Clive's car sound like a Ferrari 360
Get the precats removed i can not over stress this point enough
Pasco said:
jacjac said:
Still have pre cats fitted and the standard main cat. I do a few minor mods myself but removing manifolds and pre-cats is beyond me. The cherry bombs or sleeving are reasonable value. With my limited knowledge what effect do these options have on back pressure to the engine? I do not want to loose any power!
I have no reasons to keep the precats in place and plenty to remove them.1 It is not required by law to have them fitted in this country and will not effect your mot.
2 Under bonnet temperature will be reduced dramatically once removed
3 you will gain between three to five hp as a result of getting rid of them.
4 the exhaust note will be improved but not too loud.
If i were in your shoes i would have the precats removed and the back box sleeved ask them for a price to do both
Trust me you will not regret it Edit to add i found no issues with back pressure and would not fit cones in the manifolds ether
Edited by Pasco on Tuesday 15th April 12:04
clive f said:
Griftwood said:
My griff came with no pre-cats, I want to make it louder tho! If I got my back box sleeved, will it still get thru an MOT?
,2 ways to do it I guess?1. Remove the box and replace it with a pipe
2. Cut the pipe either side of the box and insert a tight fitting pipe to block the baffle
Which one's best?
Putting it back on:
Would the pipe/box have to be welded back on? Or can some type of arrangement with sleeves, exhaust clamps and fire gum be used?
Edited by Griftwood on Wednesday 16th April 13:07
Aye up!
Had mine done at Racing green a while back, normal method is to cut the back box, take out wadding, cut perforated pipe out and weld in a straight through pipe. I asked for the wadding to be replaced as when you weld you can't get all the way round the new solid pipe so gasses will escape into the back box chamber causing the sound to be a little tinny which is why I asked for the wadding to be replaced on mine. Had many positive comments on the sound of my Griff however I would need to get silencers if I wanted to do a track day as it was approx 112db at 4000rpm, not under load. I've left the pre cats in, consensus was it wouldn't make a huge amount of difference to the sound.
Had mine done at Racing green a while back, normal method is to cut the back box, take out wadding, cut perforated pipe out and weld in a straight through pipe. I asked for the wadding to be replaced as when you weld you can't get all the way round the new solid pipe so gasses will escape into the back box chamber causing the sound to be a little tinny which is why I asked for the wadding to be replaced on mine. Had many positive comments on the sound of my Griff however I would need to get silencers if I wanted to do a track day as it was approx 112db at 4000rpm, not under load. I've left the pre cats in, consensus was it wouldn't make a huge amount of difference to the sound.
Edited by Griffrich on Thursday 17th April 10:02
Chimjunkie said:
I really want to do something with mine. But i also really dont like the hollow drainpipe sound at tickover which many modded exhausts have. Would love to put a system together which has a bypass valve that opens on near full throttle
You need to talk to Mooshunter then Back to original OP - if you want to do trackdays, then the standard Griff 500 is just below most circuit limits. Donnington is, I think, one of the most fussy, and you are probably over that one (98 dB). However, it seems to me that circuits are getting more strict over noise, and limits are only going one way. If you go ex-standard, you may need a set of trackday silencers. They sound naff on the outside, but inside you have a big hat on anyway, so can't really hear much. Take them off when you are done. Alternatively, only go to noisy tracks. Cadwell (105 dB) is a cracker.
TVR Moneypit said:
Donnington is the most fussy? WTF!
Its right next door to a busy bloody airport?
I'm not diss-believing what you are saying, I just cant understand the stupidity of really strict noise limits at a track when there is a whopping great big airport next door.
Ha! You'd be amazed what happens from just a few complaints!Its right next door to a busy bloody airport?
I'm not diss-believing what you are saying, I just cant understand the stupidity of really strict noise limits at a track when there is a whopping great big airport next door.
TVR Moneypit said:
IMHO cat removal is a must.
Ideally yes, but wouldnt it struggle more to get thru an MOT without the cat?Griffrich said:
Aye up!
Had mine done at Racing green a while back, normal method is to cut the back box, take out wadding, cut perforated pipe out and weld in a straight through pipe.
Hi Rich Had mine done at Racing green a while back, normal method is to cut the back box, take out wadding, cut perforated pipe out and weld in a straight through pipe.
Thanks for that, but I tohught sleeving got its name from actually putting tight fitting sleeve over the baffle, thats how my Tuscan cans were done, seems a lot less work? Still not sure about the best way to do my Griff, as I said above tho.
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