6 replies to this topic

[merther]

I'm building a car for hrcr road events. I plan to fit a centre exit, but am unsure which route to go? I've been looking at the replica original works exhaust but there single silencer and I'm wary of failing the noise test. What everyone else running, bore size etc?
Thanks

[Cooperman]

It is quite tricky to get within the limits and a 'works' replica will be far too noisy.

A Maniflow twin-box centre exit is the best and strongest with a 'cherry-bomb' centre silencer as they came already 'skid-plated' for rallying. However, after a few events they get a bit near the limit for decibels. The solution I use is a Maniflow 'cherry-bomb in the tunnel and an RC40 as the back box. I weld an additional 1.2 mm thick steel sheet to the underneath of the RC40 as the skin is a bit thin, and weld skid plates on each end to prevent damage on rough roads. Then I modify the rear fixings to prevent the exhaust being torn off on rough roads.

At the front, where the Y-piece goes onto the LCB I drill upwards through the clamps, after tightening them, and tap then 1/4" UNF, then fit short screws through the clamp, Y-piece wall & LCB wall, using Loctite to secure them. That has always worked. The entire exhaust pipe is welded into one unit with no joins/clamps. after the Y-piece to pipe joint.

[rally1380]

I use one of these.....

 

http://www.minispare...haust.aspx|Back to shop

 

Utter bombproof and passes noise ever time. Brilliant exhausts and very well made with skids already welded on from new so no modification needed.

 

At first I used to clamp the two sections together but ended up doing as Cooperman suggests and welded the two sections together.  I run it with a stage 2 Maniflow LCD - again very well made...like all their products.

 

EDIT - Engine size and spec will dictate what bore size exhaut you go for.

Edited by rally1380, 19 January 2015 - 09:43 PM.

[fwdracer]

 

It is quite tricky to get within the limits and a 'works' replica will be far too noisy.
A Maniflow twin-box centre exit is the best and strongest with a 'cherry-bomb' centre silencer as they came already 'skid-plated' for rallying. However, after a few events they get a bit near the limit for decibels. The solution I use is a Maniflow 'cherry-bomb in the tunnel and an RC40 as the back box. I weld an additional 1.2 mm thick steel sheet to the underneath of the RC40 as the skin is a bit thin, and weld skid plates on each end to prevent damage on rough roads. Then I modify the rear fixings to prevent the exhaust being torn off on rough roads.
At the front, where the Y-piece goes onto the LCB I drill upwards through the clamps, after tightening them, and tap then 1/4" UNF, then fit short screws through the clamp, Y-piece wall & LCB wall, using Loctite to secure them. That has always worked. The entire exhaust pipe is welded into one unit with no joins/clamps. after the Y-piece to pipe joint.

For my next road car (lowered on 10's) - I'm going the other way. Maniflow Rear box and RC40 centre box (skidded).

[Tahiti Joe]

I run the same as rally1380 1.75 centre exit. Very tough setup, has had a fair bit of abuse now and apart from the scratches and dents is still as good as the day I got it. Only thing against Maniflow systems is I find the paint lasts all of 10 minutes... I'm running just under 100 bananas and still on a 1.75 system with no plans to change.

[rally1380]

Only thing against Maniflow systems is I find the paint lasts all of 10 minutes...

 

Yeh agree...though my car was on fire the first time I got the exhaust properly up to temperature.

[merther]

Thanks all for help.
Settled with a maniflow system as suggested.