Renault 5 Exhaust Diameter

[malcolm]

I'm thinking about making an exhaust for the Gordini. The original Renault 5 Alpine exhaust is not suitable as it has a transverse silencer, but the 1.3 or 1.4 exhausts (same) look like they will sit in roughly the right spot. See the Bosal page

I'll need to modify the front of the pipe under the car to clear the floor. Has anyone else fitted a R5 exhaust to a R4 - what else did you need to do?

Also does anyone know the diameter of the pipe on the 1.4 R5 (non-alpine) exhaust?

 

[malcolm]

Found part of the answer - the exhaust clamps are numbered for the external diameter of the pipe, so the Alpine is 48mm OD, and the TS/TX 45mm (R4 is 35mm). Fairly close.

Edit> Bosal seem to have dropped the R5 exhausts too. I'm trying Renault at the moment, but an aftermarket supplier of silencers and home made pipe might be the answer for me (for others there are plenty of people who will make exhausts to fit in stainless).

 

[pepper]

I'd go for the stainless option, keeping a mild steel exhaust from rusting out quickly without aluminiumising it makes them very fragile.

or get a stainless steel silencer with mild steel pipework to keep the noise levels down, because stainless does have a different sound to mild steel.

 

[malcolm]

Had a quote from Renault - £115 for a TX rear silencer which seems a little pricy. They are also available from Marathon Euroflow at under £50.

I'd make up a stainless system, but it seems tricky to find a suitable silencer that isn't going to be too noisy and/or blow it's stuffing out. Could always make the silencer myself.

Would be an idea to make a stainless underfloor pipe to save having to make another when it goes rusty.

 

[John Doe]

Now I have a similar dilemma, what pipe diameter should I use for my Alpine engine?

 

[malcolm]

I've still not made my exhaust but I have found the parts.

I'm going for stainless steel but I don't like the aftermarket silencers as they tend to be too noisy. http://www.exhaust.uk.net/english.html can make silencers in a few sizes. I'm going for the 150mm * 100mm body. It will need to be welded to the pipes on both sides.

http://www.merlinmotorsport.co.uk/EXHAUSTS-Jetex-Exhaust-Parts/c223_224/index.html supply bends and pipe.

The outside diameter of the downpipe on the Alpine is 45mm, so I'll use 1.75 inch (45mm) pipe (internal diameter is 45mm) for my system.

I will have a single silencer. The rear of the car is the best place for it for noise reduction. The tailpipe length is important for reducing noise. I don't have a method for quickly calculating silencer noise any longer, but I will extend my tailpipe into the silencer so it is at least 250mm long.

 

[John Doe]

Thank you Malcolm.
Then I will go with 45mm for the pipe but I am not sure about rear silencer, should I go for standard one or should I go for non standard, the one that looks like big pipe (not sure how to say it in English). The one that I have on the car is not R4 type.

 

[malcolm]

The standard R4 silencer is very restrictive. It's OK for the GTL at 34bhp, not quite so good for a GTL with a R5 carb (45bhp) and I expect it would really slow an Alpine engine.