Discussion
I need a new exhaust. Currently i have a 1.75" RC40 and maniflow LCB on a pretty powerful motor with a 296 cam and i'll soon be fitting a webber 45.
I was going to go for a 1 7/8th maniflow system which should fit over the 1.75 Y piece, and go for a large tail pipe.
However for best performance, i guess theres a compromise between mid range and out and out power but what do you chaps recommend? Dont really want to replace the whole lot in 2", and id quite like a maniflow system. Whats the best diameter and tail pipe to go for?
I was going to go for a 1 7/8th maniflow system which should fit over the 1.75 Y piece, and go for a large tail pipe.
However for best performance, i guess theres a compromise between mid range and out and out power but what do you chaps recommend? Dont really want to replace the whole lot in 2", and id quite like a maniflow system. Whats the best diameter and tail pipe to go for?
Keep the size down. Look at factory rally cars, little pipes, long cams. With a lairy engine, you want to keep your gas speed up and maximise flow extraction. I'm running a maniflow system into a single box RC40 with virtually the same engine, it is a bit loud for everyones liking but sized about right. I'd try and keep it the size of the LCB collector, through an absorbtion box and then whatever outpipe.
As soon as I get the supercharger back on, I'm going to run the biggest, loosest box as I can to shut it up. I'm having problems with the locals THINKING I'm breaking the speed limit as the car is rock hard, legally very loud and looks like it's going over 100. If I shut it up, it'll keep them quiet.
Seems people in the UK are getting used to the 70dB noise limit which DOESN'T apply in this country.
I'd have a look at maniflows reverse cone system. That would be ok with a 296.
As soon as I get the supercharger back on, I'm going to run the biggest, loosest box as I can to shut it up. I'm having problems with the locals THINKING I'm breaking the speed limit as the car is rock hard, legally very loud and looks like it's going over 100. If I shut it up, it'll keep them quiet.
Seems people in the UK are getting used to the 70dB noise limit which DOESN'T apply in this country.
I'd have a look at maniflows reverse cone system. That would be ok with a 296.
To meet the noise requirements for rally cars, I use a Maniflow 'Cherry-Bomb', the shorter one which is, I think, 13" long, leading into an RC40 centre-exit rear box, all at 1.75" dia.
This seems to work really well and is always within the noise limits. I add skid-plates to the front and rear of the RC40 and wels the entire system up into one continuous system from 'Y-piece' to tail-pipe.
Power is c.117 bhp at 6200 with a 286 cam and twin 1.5 SU's, etc, etc.
This seems to work really well and is always within the noise limits. I add skid-plates to the front and rear of the RC40 and wels the entire system up into one continuous system from 'Y-piece' to tail-pipe.
Power is c.117 bhp at 6200 with a 286 cam and twin 1.5 SU's, etc, etc.
Haynes - Twin box RC40 at normal (1.75" ) pipe diameters. As LM says... keep the gas speed up.
LM - on your supercharger you'll still need a twinbox to keep the locals happy. Only Turbo's have a rotary muffler effect and hence can run single box systems.
LM - on your supercharger you'll still need a twinbox to keep the locals happy. Only Turbo's have a rotary muffler effect and hence can run single box systems.
Edited by fwdracer on Thursday 19th October 08:54
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