Thread: V8 Intake -Is this too restrictive/too hot?

I thought the exact same thing you did with my original carbie setup. And I was determined to minimise the distance the air would have to travel through. So I changed it to LPG and configured it like so:



I had it passing through the bonnet with a filter on it... The gains weren't anything impressive. So I have now configured it like so to allow me to put the filter back inside the engine bay:



So in short... No matter what you do, while it will technically be an improvement, you won't notice a difference. The only time I noticed a difference was when I went to the EFI manifold. There was a notable increase of low down torque due to the longer runners in the manifold.

As for the air temperature present where the filter is located, yes it would be hotter when the car is sitting in traffic or something of the sort, but it will be close to atmospheric temperature when you are driving at 100km/h.

Stirling,

Were you running lpg when you had the carbs on it? Am wondering if you noticed an improvement when you went to LPG only and got rid of the carbs?
I presume you're also lpg only with the efi manifold? I'm not sure if I want to lose the ability to run petrol as a backup........

When I was on the carbies, I was running petrol only. I decided to do a LPG only setup as it let me increase the CR to 12:1. Most of the time you notice a power loss when going from petrol to LPG, hard to say if there was an increase of power. The place that did the LPG installation did a dyno tune and it got 120Hp with 300lb/ft at the rear wheels. I would be more inclined to say that it stayed the same.

Yes, i am running LPG on the efi manifold. I got the injector ports welded up and just fitted the mixer ring up stream of the throttle body. I'm pretty sure the mixer ring I am currently using is causing a lot of power loss due to the size of the orifice. I designed a new one, but I haven't fitted it yet.

I don't regret doing a LPG only setup. I have a 180L gas tank and I can do close to 1000K's off it. And if I do run into problems I have a hose which allows me to run the engine off BBQ gas bottles.

If anyone is curious. This is the mixer ring I designed. Will be interesting to see how it goes when I fit it. It SHOULD be better... but you never know.

It certainly looks good .

Originally Posted by stirlsilver

If anyone is curious. This is the mixer ring I designed. Will be interesting to see how it goes when I fit it. It SHOULD be better... but you never know.

Is the idea of the ramped edges to provide less obstruction to air flow than the typical squared off edge to the mixer ring?

Yup, exactly.

Would there be any benefit to making the outlet taper less at the expense of a steeper inlet taper?
It'd give you less turbulence, but I guess you need a certain amount of turbulence for mixing anyway.