Dirk's Avante

[islandman]

building you own exhaust box now! no end to your talents Dirk...and time

[Spacenut]

Good work Dirk, interesting to see the innards of the MGF exhaust, they clearly designed it to work over a wide operating range, nice and muffled at low speeds and approaching a straight-through at full chat!

Turbo Scooby manifolds are horrible, I read that Subaru deliberately made the downpipes unequal length to accentuate the "flat" sound, specifically for the UK market! OK, so the turbo more than makes up for the shortfall, but even so, making things worse just to get a different sound is not what performance motoring is about...

[Dirk]

building you own exhaust box now! no end to your talents Dirk...and time

Well its not built so might be beyond me and go pear shaped

Dirk

[Dirk]

Turbo Scooby manifolds are horrible, I read that Subaru deliberately made the downpipes unequal length to accentuate the "flat" sound, specifically for the UK market! OK, so the turbo more than makes up for the shortfall, but even so, making things worse just to get a different sound is not what performance motoring is about...

That may be true, but the convenience that the turbo manifold gave and the overall sound I had in the Nova was pleasing to me, possibly more to do with the MGF back box than the manifold I guess given the much shorter run of pipes will have also helped?

Dirk

[Dirk]

Here are a couple of pics of the header tank now installed





This makes the routine items that need checking and topping up oil and water accessible from the small opening I have got with no need to open it up.

Back to the exhaust I was hoping that if I reduduced the overall depth from 165mm to 100mm it might have fitted.



Its obviously still a long way off. I need to have a rethink. I still want to use the basic design of the MGF box but I think it will be a single in and single out run up the side of the engine.

Dirk

[islandman]

Jim's back box done by fellows speed shop fits behind and has a nice note to it, maybe get him to take some measurements

[Spacenut]

That may be true, but the convenience that the turbo manifold gave and the overall sound I had in the Nova was pleasing to me, possibly more to do with the MGF back box than the manifold I guess given the much shorter run of pipes will have also helped?

Dirk

Point taken - and in their favour the turbo manifolds are certainly more compact than the non-turbo alternative.

Is there room to have twin boxes, one either side of the engine, like a 911/Boxster? The only issue would be if you wanted to retain a crossover (I guess you would), as there is no room for a back box of any sort, it would seem

I've not come across an exhaust where the silencers are in each cylinder bank and the system merges after them with no back box, but I guess there is no reason why it shouldn't work? You might be able to get one or two small cylindrical silencers (not Cherry Bombs but that sort of size and shape) to fit behind the engine, where a single MGF box would be too big.

[Dirk]

Jim's back box done by fellows speed shop fits behind and has a nice note to it, maybe get him to take some measurements

The MGF box fitted on my Nova the issue is that the Avante is 10cm shorter and it has the double skinned back end, unlike the Nova rear valance. I think the box would have to be thinner than the pipes to get it to fit there

Dirk

[Dirk]

Point taken - and in their favour the turbo manifolds are certainly more compact than the non-turbo alternative.

Is there room to have twin boxes, one either side of the engine, like a 911/Boxster? The only issue would be if you wanted to retain a crossover (I guess you would), as there is no room for a back box of any sort, it would seem

I've not come across an exhaust where the silencers are in each cylinder bank and the system merges after them with no back box, but I guess there is no reason why it shouldn't work? You might be able to get one or two small cylindrical silencers (not Cherry Bombs but that sort of size and shape) to fit behind the engine, where a single MGF box would be too big.

Yes I want to keep the crossover, and I also want to avoid the two small cylindrical universal boxes each side, that is what I had and was not impressed with the sound.

Dirk

[Dirk]

Having spent a bit more time this evening looking at my options I think I am going with the N/A manifold the output flange ends up under the horns lower than I wanted but it is in line with the centre of the wheel so hopefully speed bumps wont be an issue. I think I can get an oval box 150mm x 200mm x 430mm to run along side the left of the engine. So I'm still looking at using the design and internals from the MGF all be it a bit scaled down and making my own box.

Dirk