Exhaust for performance???

[mad mark]

I think my baffles have gone in my back box, I can hear them rattling. So am now thinking of which system to replace it with.
I seem to remember on here that a decat with standard back box is the way to go. But has any one done any back to back testing?
Also has anyone done any back to back testing of any of the sports boxes on the market?

I'm thinking of making my own system up, but just thought I'd get a few opinions first.

Also, are my rattling baffles likely to effect my RR figure on Saturday, and Santa Pod next month?

[vixpy1]

Not sure who did them, but the decat and exhaust which diddyman has on his are the best i've ever heard

[dean_ratpac]

i have token cans on mine, like cherry bombs but with pipes in them. no packing etc. it would be nice too, if i had the time to get some made up.. time and money i don't have i'm affraid. the contact i had at McLaren who made my last set up has since left.



>> Edited by dean_ratpac on Wednesday 22 February 20:11

[gazzab]

They arent performance exhausts unless you go decat linked plus remap etc...
Noise changes are what you get.
So choices are:-
1 Standard incl cats = flymo
2 STandard no cats = quietish at tickover, great on overrun and full blast. Flames show.
3 Sports incl cats = louder at idle than number 2 but no flames.
4. Sports no cats = louder than all of the above, too loud for some, can really hear the car breathe...

[K1 CERB]

Mine are ACT...Can't vouch for the performance figures, as my old 1's had 1 baffle in 1 baffle out!
Glad to see your doin Santa Pod, I'm gonna book it tomorrow, perhaps this time we can travel together!!

K1 CERB

[Julian64]

Ever thought of linked, plus removing the baffles from your standard back box?

[trackcar]

A completely hollow rear std box sounds awesome ..

[Julian64]

Julian64 said:

Ever thought of linked, plus removing the baffles from your standard back box?

Last time I checked by local dealer walldonway was doing this as a service. It involved cutting the rear box removing the baffles and welding it up again.

Theoretically you don't improve and engine note by removing all backpressure, cos anyone knows who's run and engine with an exhaust manifold off that its not nice to hear.

You try to turn your engine into a musical instrument by giving it an echoic chamber. Hence the backbox will always sound better than the straight through sports pipes.

On a slight diversion, I think you could improve the cerb exhaust quite considerably by having a stretchy rubber bladder inside an echoic box.

I got a secondhand exhaust off a board member, and took the baffles out and rewelded it. It had no rear pipes attached but the effect of removing the baffles on a standard rear box was undoubtedly the best noise that I have ever heard comming out of a Cerb. I havn't used it because it has no rear pipes and could bring myself to alter a perfectly working one.

I got this sad with the Cobra which has two massive side pipes that need packing every so often when they push all the birdsnest out. So I ended up making little cages with different sorts of resrictions in, and packing in different ways till I found what I liked.

I was gonna, fit two sleeves inside the inlet to the backbox on the Cerb and bolt two football bladders with holes in to the pipes. But sitting down drawing this out as backbox mark 3 my medication suddenly kicked in, and I haven't let it lapse since.

[jesfirth]

My car had a rear sports exhaust with no baffles and a decat when I bought it and it was so loud. It used to shake the picture off the wall in the bedroom over the garage which was fun. You wnt get on a track with that level of noise though.

[nautique]

So what are the implications of a hollow back box on the MOT?? Will the car pass with no baffles and cats in?

Neil

[dean_ratpac]

mine passed with straight through pipes

[mad mark]

K1 CERB said:

Glad to see your doin Santa Pod, I'm gonna book it tomorrow, perhaps this time we can travel together!! K1 CERB

Hi Keith, sounds like a good Idea.

[mad mark]

trackcar said:

A completely hollow rear std box sounds awesome ..

I think it wont be long before it goes that way itself

I have heard of that, people cutting open the boxes and removing the baffles.
But how loud is it? I've got no cats and would like to be able do some track days.

But most importantly what performace implications does it have?
I'm not a power chaser, but if something needs doing then power dictates what it gets done.

[budaholic]

mad mark said:

K1 CERB said: Glad to see your doin Santa Pod, I'm gonna book it tomorrow, perhaps this time we can travel together!! K1 CERB Hi Keith, sounds like a good Idea.

Hey guys, can I tag along if your passing my way?

and Mark.... I have a pair of cats that your welcome to borrow come MOT time if ya want!

The alternative is to just find a very TVR friendly MOT testing station, like I have.

Bud

[mad mark]

Thanks Bud i'll keep that in mind.

[jesfirth]

decat and standard back box runs at about 100Dba at 2/3 revs 1m from the pipes at 45 degrees. so ok for most track days but borderline fro goodwood. Recommend you get some aftermarket track day silencers as well for emergency use on track days. They cost about £100

[ROB1]

Anyone know the best place to cut open std rear box to remove baffles? Top, bottom or cut one end off, before re-welding? Mine has started to rattle, so am thinking of trying this before possibly purchasing sports pipes. It has already been decatted.
Thanx R

[Julian64]

ROB1 said:

Anyone know the best place to cut open std rear box to remove baffles? Top, bottom or cut one end off, before re-welding? Mine has started to rattle, so am thinking of trying this before possibly purchasing sports pipes. It has already been decatted. Thanx R

Local dealer seemed to cut a big square out of the top of the box.

[mad mark]

Top of the box is what I heard, that way when its put back on the car it doesn't look modified.