Rear exit exhaust

[Pete_London]

Hi all, this is my first post.

So I'm getting close to ordering an SDV kit for an MX5, probably going to use a 1.8 JDM Import donor so I can get the LSD.

I've seen the rear-exit exhaust on the Seight and think it looks pretty cook with the clean sides... can this be done on the 4 cylinder models?

Thanks,

Pete

[Mark (smokey mow)]

Hi Pete, welcome to the boardroom.

Looking at a few pictures of the Seight exhaust system I would imagine it is possible to fit an underslung system to the Mazda SDV kit.  The design of the Mazda chassis and the arrangement of components within the tunnel and diff area is not dissimilar to the Seight so I'll stick my neck out and say that you should be able to fit it using a majority of off the shelf parts from Westfield.  The only part I can see that will need fabricating would be a link pipe to connect the manifold of the mx5 to the exhaust system under the car.

This picture may help give you an idea.  

Also consider though that an underslung exhaust system will reduce the ground clearance under the car, so if you live anywhere near speedbumps, pot holes or bumpy roads a side exhaust may be a better proposition.

[Pete_London]

Thanks Smokey, that's exactly what I was looking for...

Is there space to run the silencer along the back of the car below the boot?

Pete

[Mark (smokey mow)]

Thanks Smokey, that's exactly what I was looking for...

Is there space to run the silencer along the back of the car below the boot?

Pete

I'd say room under the back would be tight for the silencer.  The only bit of free space would be underneath the fuel tank, and this may be difficult to achieve for the rooting of the exhaust from the tunnel with the positioning of the lower suspension arms.  By this point you'll be having to get a custom made exhasut system form scratch.

Assuming your 1.8 engine would also be needing a Cat and  running quite hot, I'm not sure of the implications for this with the IVA test and the immediate proximity of the fuel tank.

[Annie]

I've seen the rear-exit exhaust on the Seight and think it looks pretty cook with the clean sides... can this be done on the 4 cylinder models?

Hi Pete,

I got a brand new, factory-built Seight this year which has now been converted to side exhausts, so I've got all the bits sitting in the garage - central exhaust, silencer, the split to either side and the rear exit panel.

Mike can send you some pictures if you're interested and he can give you any technical detail - I'm just the driver!

Annie

[BEN99W]

Hi Mike

I originally had an underslung exhaust on my ZEi. This model uses a 4 cylinder zetec engine. I've since converted to a side exit exhaust, but when I bought it the car came with a spare new rear exhaust box that locates under the rear/fuel tank. It's been cluttering up my garage for years - you'd be welcoome to come and take it away for free if it would help you.

You'd still need to get someone to knock up the rest of the pipework of course, plus a bracket on your chassis to hang it.

I'm in chelmsford, essex.

Cheers

Ben

[Pete_London]

Thanks Ben, I'll get back to you when I order the kit

Pete

[WestfieldMX5]

You could try something similar like Pollinni does.  Their side mount exhaust goes through the rear wheel arch, makes a bend over the suspension arms and exits through the rear of the wheel arch.

I don't have close-ups of the exhaust, but it's a really clever solution.  Here's the best I could find.  

[SwissWesty]

My way ...  

passed our MOT and works fine. A little to much silent though !

[WestfieldMX5]

Wonderful, exactly what I was trying to explain.  

I''ll have to do something similar to protect my left ear.  Even with good earplugs, it sometimes hurts on longer drives

Can the 2nd silencer be omitted or would that not make much difference?

I really don't like the look of the 2nd silencer in the back.  I suppose it could be hidden with a rear valance, but I don't really like those either   .

[Blatman]

There are good earplugs, and brilliant earplugs. I've had a set of these for several years. They're great in the car, on the plane, on the bike, or when the missus is snoring

[WestfieldMX5]

The ones I have are similar altough normally used for shooting.

Is it wishful thinking that earplugs are not necessary with the rear exhaust?

[Blatman]

Wind noise is often worse, especially at motorway speeds...

[chris7273]

Here is the underslung exhaust of my ZEI, placed by the previous owner (custom made). The engine is a ZETEC. May help even if it's not a Mazda SDV