One for the experts - Chessman exhaust UPDATE after RR

[Supersprint1988]

Chessman once did a CSP 297 under tank exhaust. Internal pipe diameter 51mm and narrows to 42mm.

Does anyone know what spec car these where made for ?

 

 

 

 

 

Edited by - Supersprint1988 on 16 Sep 2013 15:11:34

[Budjuggler]

No - but I think they are Cheesman

[Supersprint1988]

Sorry - indeed they are Cheesman 😳 😳 😳 😳 😳

 

[Mavic82]

No idea on the part number but in the mid 90's these type of exhaust were fitted or Australian export certainly and possibly other countries.

 

[jackb_ms]

I think a 21 was fitted with one

 

jack

[Nick Green]

There was a "Clubsport" exhaust, which had a side silencer then turned under the tank, going through two side-by-side cylinder silencers (covered to sort-of look like one) with a U-bend at the far end, exitting with a tail pipe back on the side-silencer side of the car. This was for lower-powered K 7s

 

I have seen the same style of exhaust on an R500 7, with bigger bore piping.

 

Or are you thinking of a different version again ? Might be worth emailing or calling Cheeseman Exhausts directly ?

[Dave B]

In my year 2000 assembly guide there is a "Clubsport" exhaust which is as you describe. I had to have a similar system to pass Spanish regs. I bought mine second hand from blat chat. CC don't list this anymore but might be worth a call.

Oops too slow!!!

 

Dave B

 

Edited by - Dave B on 13 Sep 2013 11:06:20

[nickh7]

ground clearance was an issue

[Supersprint1988]

Just been told that it's from a Vauxhall 2.0 16v via PM, and CC confirms that they where fitted to the 175BHP Vauxhalls.

So the question remains if it will be too restrictive for my 2.0 Zetec 200BHP engine. It is the same size engine and rpm so maybe OK ??

[Supersprint1988]

Just did a Iphone db test. 1m from exhaust pipe at 4000rpm 103dB with standard Raceline 7" can and 93dB with the extra silencer connected.

dB figures are relative of course, my subjective impression was a huge reduction in noise.

 

Probably going to make a temporary connection and take it to the RR to see if the power reduction is too much.

[Dave B]

My bhp went down from 189 to 176 by adding the extra silencer across the rear. Still feels good though.

 

Dave B

[Supersprint1988]

Hi Dave

 

Did you change the engine map after adding the rear silencer ?

Are you using the silencer with 42mm internal pipe diameter or is it the bigger R500 one with 52mm internal diameter ?

 

TIA

Carsten

[Dave B]

Yes had to have the map changed as Advised by Oily. The system I have was originally on a Lotus 7, I bought it from BC. The side silencer is repackable and where the tail pipe would have been there is a connecting pipe which bends around the left rear wheel and joins up with the transverse mounted rear silencer. Not sure who it was made by but looks very professional in SS.

 

Dave B

[Supersprint1988]

If it looks anything like this can you please measure the internal pipe diameter for me next time you are with your car.

A measurement of the end pipe would be fine.

 

Carsten

[Dave B]

Ah no, looks nothing like that. Have just crawled under car and the only join is at the end of side silencer. Pipe from there runs around behind wheel and is one part with rear silencer. Tail pipe is on off side ( for RHD car).

 

Dave B

[Supersprint1988]

Thanks Dave

 

Good to know that we are not talking about the same exhaust 😬

[Supersprint1988]

For anyone with interest in this topic I would like to share the "before and after" measurement at the RR today.

Highest red line represents the Raceline side can silencer only and lowest red line is with the 42mm bore dual silencer under tank box temporarily connected after the Raceline side can.

Please ignore the blue line.

RR print here

 

Cheers

 

 

Edited by - Supersprint1988 on 16 Sep 2013 15:22:45

[rj]

That's not bad.

 

Well done Carsten!

[myothercarsa2cv]

Looks like you'll barely notice the difference, good work I wonder if the larger bore rear pipe will improve things or not? I'd guess it's not worth it...

[zetec]

wow,i love your car!!

 

please can you send me an email with details of throttle bodies & ecu etc.

mine is on 45 carbs but I need to upgrade asap

[Dave B]

Fantastic result, wish my car had only dropped that much. A credit to you and your RR man. Forgot to add, do you have a cat fitted, I had to for Spain.

 

Dave B

 

Edited by - Dave B on 16 Sep 2013 21:55:19

[Supersprint1988]

Hi guys

 

No it's not too bad with the rear silencer box fitted.

 

Dave: There is no cat.

 

Zetec: Engine is a raceline 200bhp specs are here mapped with 4 bar fuel pressure.

[oldbutnotslow]

From memory Mark Collins had something similar made for his car by Powerspeed.

Again from memory the results were impressive. I believe that they still offer this system for a 7

[Roger King]

This brings to mind something that happened in the 70's when we were building the works Escort BDA's.

 

We normally saw around 255bhp from the engines on the dyno, although for reasons of space and convenience we ran a four into one race type exhaust system. One day it was decided to try the system actually used on the cars by way of a comparison; of necessity, to fit it in the dyno cell, we had to include a few bends that weren't on the car but the bores, lengths and silencers were correct.

 

The result was 215bhp!!!!!

 

A day or two's work with different layouts ended up with a system that lost only around 5bhp compared to the dyno system and would still fit the car. This was then fitted to a car with a knackered engine and given to (I think) Ari Vatanen to try. His response was that the new "development" engine he'd been given was fantastic and a huge improvement on the standard spec.

 

It's difficult to believe in this era, but things really were that 'suck it and see' in those days.