Exhaust Options

Exhaust Options

Author
Discussion

phn

Original Poster:

335 posts

242 months

Thursday 16th March 2023
quotequote all
Hi there,

I find the standard exhaust on my Chimaera has a bit of an annoying resonance / howl at 60-70 mph, which gives me a bit of a headache on longer drives.

Could anyone recommend an exhaust setup or aftermarket option that would be less intrusive whilst still maintaining the lovely TVR sound when putting your foot down.

Many thanks!

sawman

4,915 posts

229 months

Thursday 16th March 2023
quotequote all
are you sure its standard, the standard one on my 400 had no issues. Now have swapped out the original manifold for ACT without pre cats and still no droning - just sounds ace, loud enough, but not so much as to be a pain

no doubt someone will be along in a bit and suggest taking the roof off driving

Classic Chim

12,424 posts

148 months

Thursday 16th March 2023
quotequote all
If yours is a 450 they do tend to have more of a drone at certain engine revs.
I’m pretty sure it’s much less apparent with pre cats fitted.
Your exhaust might look standard but it’s worth checking manifolds still have the pre cats in them?
My 450 has always droned more since pre car removal.
Sleeving exhaust just causes that nauseous boom to now be in two places at once biggrin
Sleeved silencer or even 1/2 sleeved used to be a big thing on here…
If it’s been sleeved there will be evidence of welding work on usually the top of your muffler box.

I found if I left my drivers window open 1/2 inch this made the headache take longer to get me wink
And in truth it just removed some of the resonance that the drone is causing.
Or I drove faster ( risky ) so usually slowed down.
I noticed whilst driving through France at a steady 70 I got a headache yet at 80 the engine seemed in its sweet spot and less drone. Mpg increased too ?


DangerousDerek

8,655 posts

219 months

Thursday 16th March 2023
quotequote all
Fit a turbo hehe

Harry Flatters

142 posts

257 months

Thursday 16th March 2023
quotequote all
I have a 450 and the standard exhaust was muted and definitely not prone to drone at any speed.

I have since had the silencer fully sleeved and the box repacked (knocks out some resonance apparently) and is now just what I (maybe not the neighbours!!) wanted. On start-up and idle it sounds amazing. Driving at all speeds, I can only assume that all that lovely sound is behind me, because the cabin is still perfectly comfortable, sound-wise, and definitely not droning at any speed that I can discern.

My cat and pre-cats are all still in place and with no other mods, other than the sleeving. Also, it's a fraction of the price of the lovely ACT cherrybomb solution.

Classic Chim

12,424 posts

148 months

Thursday 16th March 2023
quotequote all
Sleeving promotes faster exhaust gas removal and clearly with no muffling effect will be well over 100db and over at high revs.
Pre cat and removal of main cat adds power but does create more noise from the engine bay at certain revs.
Fully De cat and fully sleeved can easily reach 120 db
The standard later system including pre cats and main cat in place is around 84db as my car was tested at Bedford after a complete engine rebuild but standard exhausts at 4000 revs
My same 450 de Catted and pre cats removed using standard exhaust recorded 94 db at 4000 revs with an exhaust probe directly behind one of my tail pipes.

I’d expect your 4.0 with cats but sleeved will be similar to the 94db figure. Loud biggrin
Anything over 100 leads to ear drum issues and deafness,,,,

I drove mine for many years and largely avoided the drone but it was there. It’s only at certain revs so I avoid them. Remembering back to my earliest days I drove it for 12 months almost every weekend on long journeys taking the dog for a walk on the coast or some such place, 10,000 miles that first year and never remember I had drone or headache issues. Then I found this place and read about more power,, 5ph I think pre cat removal offers ( barely enough to notice) so took them out anyway and had drone ever since.
Cooling in the engine bay drops but not by much.
The one sure way to remove it is some after market manifolds which is really the only true solution imho.
For the o/p who is getting drone or resonance you’d be best to check if pre cats are in each manifold.
There may well be no signs of removal as it’s fairly easy to remove them without causing any disturbance to the pipes themselves.

You usually have to disconnect the Y piece from at least one manifold to check which is not for the faint hearted to attempt.
Alternatively you may be able so see them by removing lambda sensor and using a small camera to check.
If your handy with spanners look up how to remove and critically how to re instate exhaust system and its pitfalls
Or alternatively take it to a Tvr man and let him struggle instead.
Probably only charge a few hours if not too busy just to check.





Edited by Classic Chim on Thursday 16th March 13:34

phn

Original Poster:

335 posts

242 months

Thursday 16th March 2023
quotequote all
Classic Chim said:
If yours is a 450 they do tend to have more of a drone at certain engine revs.
I’m pretty sure it’s much less apparent with pre cats fitted.
Your exhaust might look standard but it’s worth checking manifolds still have the pre cats in them?
My 450 has always droned more since pre car removal.
Sleeving exhaust just causes that nauseous boom to now be in two places at once biggrin
Sleeved silencer or even 1/2 sleeved used to be a big thing on here…
If it’s been sleeved there will be evidence of welding work on usually the top of your muffler box.

I found if I left my drivers window open 1/2 inch this made the headache take longer to get me wink
And in truth it just removed some of the resonance that the drone is causing.
Or I drove faster ( risky ) so usually slowed down.
I noticed whilst driving through France at a steady 70 I got a headache yet at 80 the engine seemed in its sweet spot and less drone. Mpg increased too ?
Thanks for the relies, Classic Chim.

The symptoms you mention are exactly those I have in my 450. At 60-70 mph the noise is unpleasant, but let the speed creep up to 80 mph (on a private track) and it's fine. I already had the silencer box checked and repacked with sound insulating stuff (the previous insulation had burnt out) and the car is not sleeved. So it seems like it must be something to do with the cats. I'll ask Mat Smith if he can take a look at them, as the car is there now, having the steering sorted.

I'll also try your "window down" trick when I next drive it to see if that helps! smile


macdeb

8,492 posts

254 months

Thursday 16th March 2023
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'cherry bombs' you can have them made in differing lengths.

Classic Chim

12,424 posts

148 months

Thursday 16th March 2023
quotequote all
phn said:
Thanks for the relies, Classic Chim.

The symptoms you mention are exactly those I have in my 450. At 60-70 mph the noise is unpleasant, but let the speed creep up to 80 mph (on a private track) and it's fine. I already had the silencer box checked and repacked with sound insulating stuff (the previous insulation had burnt out) and the car is not sleeved. So it seems like it must be something to do with the cats. I'll ask Mat Smith if he can take a look at them, as the car is there now, having the steering sorted.

I'll also try your "window down" trick when I next drive it to see if that helps! smile
Mat is the man.
A tap with a screwdriver will probably tell him if it’s pre cats are in place. He has one finely tuned ear I believe yes

Classic Chim

12,424 posts

148 months

Thursday 16th March 2023
quotequote all
macdeb said:
'cherry bombs' you can have them made in differing lengths.
This is the best solution without spending fortunes.

phn

Original Poster:

335 posts

242 months

Thursday 16th March 2023
quotequote all
Classic Chim said:
This is the best solution without spending fortunes.
Are cherry bombs significantly louder than standard, or just a different tone?

If the droning is being caused by the (possible lack of) pre-cats - would the Cherry bomb exhaust help with this? Thanks!

Classic Chim

12,424 posts

148 months

Thursday 16th March 2023
quotequote all
The Cherry bombs offer less back pressure than standard exhaust so helps remove the gasses similar to sleeved exhaust but it’s a raspier sound and does baffle the sound.
Sleeved means no silencing at all in essence.

blaze_away

1,502 posts

212 months

Thursday 16th March 2023
quotequote all
You could try fitting trackday cans over the ends of the exhaust tips. They clamp on with standard exhaustclamps and will reduce the noise levels to maybe a sufficient amount to allow longer trips at motorway speeds to be mote tolerable. Then for A-B roads pull them off tp enjoy the rumble.

If you are anywhere near Rugby I have a pair you can try.


kris450

658 posts

193 months

Thursday 16th March 2023
quotequote all
Classic Chim said:
I found if I left my drivers window open 1/2 inch this made the headache take longer to get me wink
This ! 100% give this a go before you go down the road of spending money. The difference this makes for me is staggering as I have the same sort of issues at motorway speeds.

The number of times I've taken the car to Le Mans, and cruising at the higher French autoroute speeds is now a genuine pleasure.

phn

Original Poster:

335 posts

242 months

Friday 17th March 2023
quotequote all
blaze_away said:
If you are anywhere near Rugby I have a pair you can try.
Thanks so much for the offer but a bit far for me, I'm in darkest Norfolk!

phn

Original Poster:

335 posts

242 months

Friday 17th March 2023
quotequote all
kris450 said:
Classic Chim said:
I found if I left my drivers window open 1/2 inch this made the headache take longer to get me wink
This ! 100% give this a go before you go down the road of spending money. The difference this makes for me is staggering as I have the same sort of issues at motorway speeds.

The number of times I've taken the car to Le Mans, and cruising at the higher French autoroute speeds is now a genuine pleasure.
I'll give it a try tomorrow. smile

Also I did get the cat's checked and they are in one piece, so I guess I'll just live with it!

NeoVR

434 posts

170 months

Tuesday 21st March 2023
quotequote all
Just to chime in - I observe the same with my 450. Standard exhaust, main cat in but no pre-cats.
Cruising around 70 has a kind of resonance that goes away at 80.

I’m currently considering cherry bombs though, because as far as TVRs go..the stock exhaust is quite tame biggrin

phn

Original Poster:

335 posts

242 months

Tuesday 21st March 2023
quotequote all

NeoVR said:
I’m currently considering cherry bombs though, because as far as TVRs go..the stock exhaust is quite tame biggrin
Let us know how you get on if you do get Cherry Bombs - would be interesting hear how they are!

von vardo

30 posts

131 months

Tuesday 21st March 2023
quotequote all
phn said:
Let us know how you get on if you do get Cherry Bombs - would be interesting hear how they are!
I’ve got the ACT system on my 450, it sounds like a beast!

pja

270 posts

224 months

Tuesday 21st March 2023
quotequote all
I very nearly went for the ACT cherry bomb system but didn’t like the flexi front pipe they supply,
(In my mind flexi pipes are a bodge or temporary fix at best)

I spoke to JP Exhausts who fabricate the exhausts for ACT, he agreed about the flexi pipe & said he could build a system on the car but the price jumped up to £1250+vat

In the end I took the car to a very helpful guy at Cybox on the Wirral (fairly local to me) & he custom built me a cat back stainless system with cherry bombs for £750 all in

Very happy with the fit & sound, the only down side I can see is the tail pipes on the ACT are more polished,