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Sat Nov 08, 2025 8:31 am

I got a guy wanting to build a rat rod bug and were discussing a twin turbo set up ( I do have some really tiny turbo's that'd be great for this ) , so since I dont do a lot with full body beetles im wondering if ya'll know a a dual exhaust that will fit in one? he's fine with no deck lid and removing the rear apron.
I dont want a typical beetle exhaust as it sits to low, im thinking of the duals for buggy's as they sit high enough that the turbos could still gravity drain easily and without the lid and apron, length wouldn't be an issue but im concerned about their width.
and yeh, a custom exhaust could be made, just figured gutting the packing and welding on a turbo flange to a premade set would be simpler

Sat Nov 08, 2025 10:56 am

Like the dual cannon from a buggy?

Sat Nov 08, 2025 10:57 am

Sat Nov 08, 2025 12:01 pm

slayer61 wrote: Like the dual cannon from a buggy?

Just a thought. If the dual cannons were chosen that might create an odd "pulse" in the exhaust flow since cyls 1&2 and 3&4 fire next to each other. After they fire they would have to wait until the other side fires & that might slow down the exhaust/turbo speed. Wouldn't it be better to pair cyls 1&3 then 4&2 together for smoother flow? I don't know if this would really be an issue, just thinking aloud.

Sat Nov 08, 2025 12:59 pm

daveblank wrote: slayer61 wrote: Like the dual cannon from a buggy?

Just a thought. If the dual cannons were chosen that might create an odd "pulse" in the exhaust flow since cyls 1&2 and 3&4 fire next to each other. After they fire they would have to wait until the other side fires & that might slow down the exhaust/turbo speed. Wouldn't it be better to pair cyls 1&3 then 4&2 together for smoother flow? I don't know if this would really be an issue, just thinking aloud.

Yup, even the guys running 2 cylinder 36hp turbo engines at Bonneville have problems with exhaust pulsing.

Sat Nov 08, 2025 5:35 pm

Part of my thoughts on the dual cannons was that the “glass pack” part, once cleared out , would make a good expansion chamber. Also the turbos being smaller will help too. Ive run these same turbos as duals on a corvair powered rail which granted has 2 extra cylinders and a more even firing order but they spooled quick enough to be all in by 2000-2200 rpm and even made a lb of boost just revving the engine. I also put one on a single cylinder pulling tractor, that one did pulse but once it got up past a couple psi it evened out.
Im sure cam choice would affect this too