134 replies to this topic

[N/A-PWR]

Good Stuff,

 

Must feel strange doing something different.

[greens nice]

Good stuff, have you done a wot test and pulled the plugs yet?

I imagined this to have a pretty cranky idle hehe

[Steve TPF]

. And put a nice sharp edge around the opening of the carb spacer to help shear the fuel.

 

I hate to sound stupid but WTF do you mean by that?

[Steve TPF]

Thanks for enlightening me.

[N/A-PWR]

Good runner RBT,

 

thank's for posting the You-tube. 

 

You can only get better.

[Dave6179]

Your exhaust is the same as I made a few years ago, although my pipes were less than 1/4 inch different in length. Did you notice the different sound it made? I didn't listen to the wireless for weeks after they went on!

[Steve TPF]

A second dumb question while I'm thinking of it: why are inlet manifolds always made of alloy? Every car I can remember lifting the bonnet on has an alloy inlet manifold, even the really old Hillman and Morris that I drove when I was younger. Was it cheaper/easier to cast or is there some technical reason for the alloy choice?

[N/A-PWR]

I will take a guess Steve,

 

Cheaper to make, as is only 600 degrees melting point for one.

not sure if it is lighter than a steel one, but could also have less heat transfer properties that help.

[Steve TPF]

Cast iron manifolds were very common on older inline engines and even more common on V8s. Alloy is lighter but not as cheap as iron.

 

Ok, but the weight difference between an allow manifold and a cast iron one would hardly be enough to improve performance, so why use alloy if it's more expensive? Is GASPOWER right about heat transfer being the reason?

 

[N/A-PWR]

Did a bit of reading on the net Steve,

 

and Oldjohnno is right as usual, where the cast iron is cheaper to make, and has been on inlet manifolds too, there are arguments to about which is better,

 

and although they both have Pro's and Con's, there is no real advantage ( lean spots/less oxygen atoms ).

 

The introduction of double walled manifolds, was to heat or cool the manifold as needed, in which even altitude play a part ( for those who travel a lot ).

 

All these manufacturing methods were employed to find better ways to produce Power and Economy, but it was not till the Intercoolers/superchargers/ etc, that created cooler air.

 

Ok, but the weight difference between an allow manifold and a cast iron one would hardly be enough to improve performance, so why use alloy if it's more expensive? Is GASPOWER right about heat transfer being the reason?

 

and as Oldjohnno has always said about differences of opinions, I read quite a few different sites to get the drift.