Aftermarket Intake Manifolds?

[Suspence]

Anything out there? Looking for something to allow more air flow...

[bimmerteck]

Short of an ITB setup there isn't really anything that flows better than the OBDI manifold.

[nando]

Er, M20?

[blefevre]

Extrude hone intake is about $600
ITB kit is about 3,000

Neither are worth it, but ITB's are pretty sweet if you have the cash to blow on random stuff.

[bimmerteck]

Er, M20?

doh, coulda sworn I was still in DOHC land. :oops:


Extrude hone, or ITBs as pictured below.

[billybobjoseph]

There you go! Then get the 19lb mustang injectors and some oversize valves installed, get a custom built header and a little larger exhaust set up with a high flow cat from summit. Then get a programmable chip and whoo hoo!!!

[jlevie]

Everything I've seen says that the mass flow limit of an M20B25 engine is the head, not the stuff that bolts to it.

[nando]

Everything I've seen says that the mass flow limit of an M20B25 engine is the head, not the stuff that bolts to it.

Its true to a point, but theres really nothing wrong with the head, and even in stock form the intake runners flow less than the head inlets. An extrude hone could be worth something.

[billybobjoseph]

have a machinist bore out the valve holes a little and put in some bigger valves

[nando]

That wont solve anything, it will just make the existing restriction worse.

[billybobjoseph]

Why is that?

[Todd Black 88]

Re read post #8

[billybobjoseph]

Ah ok, it's the ports

[digger]

Its true to a point, but theres really nothing wrong with the head, and even in stock form the intake runners flow less than the head inlets.

That wont solve anything, it will just make the existing restriction worse.

I don't agree with that analogy at all. I realising you were simplifying things.

If for example the manifold was the most restrictive part of the engine (i am not saying it is just using it as an example) that doesn't mean that improving the headflow or other parts of the inlet won't make gains.

This is because while it may be the most restricive part of the engine on a relatively stock engine it is not so excessively restrictive enough to eliminate any gains from freeing up flow elsewhere.

If someone takes a stock 885 head and does a good port job and flow numbers increase to 200CFM without overly increasing port volume then there will be good gains even if they still use the stock AFm, intake, TB and airbox. Obviously improving everything is better......

[billybobjoseph]

I'm really liking this thread. I'm pulling my intake mani in the next couple of weeks to replace gaskets and rebuild my injectors. I'll do some measurin and figgerin and post it all on here.