Aftermarket Intake Manifolds?

[nando]

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......

not really what I meant. For the cost, merely increasing the valve size isnt going to do much if you leave everything stock. And there is basicaly nobody here willing to put in the work needed for a 200 cfm port.

Im willing to bet my ports are the same or worse than stock, yet the factory intake parts ae still highly restrictive on my engine.

[digger]

not really what I meant. For the cost, merely increasing the valve size isnt going to do much if you leave everything stock. And there is basicaly nobody here willing to put in the work needed for a 200 cfm port.

Im willing to bet my ports are the same or worse than stock, yet the factory intake parts ae still highly restrictive on my engine.

you say highly restrictive yet with some more CC and more cam you are still good for ~230-240bhp on a stock head and manifold. Improving any aspect of the engine is a step in the right direction though an improvement in any one part is not enough for large improvements as you are aware.

I am trying to find a place that does more than just your basic P&P to do some headwork for me. Got so many things i want to try out. Most likely will never happen and i'll just get a E36 M3 with its nice S50B32

[morerevsm3]

stock inlet ports flow enough to make ~222hp @ .300 lift, 269 @ .400 lift, stock manifold reduces that by a fair chunk, but can't remember the exact numbers

[Brandon12V]

I'd like to see more work done with a custom manifold taking runner length vs. plenum volume vs. port size into consideration, but I don't realistically see anyone(or company) going out their way to do this without more market demand. At least, not on an NA m20. Unless you're a die hard m20 fan, there's no point in trying to find that extra hp. The R&D needed would be expensive without the tools/fab skills/machining equipment, and knowledge, readily available to you. The only alternative I've considered is converting to a triple-carb setup. Like the kind that were/are available on the old TR6.

[Suspence]

I guess that the I head is more flowing than the ETA manifold? Along with the throttle body?

[nando]

Yeah, a lot more. The eta manifold and tb are like breathing through a bendy straw..

[Suspence]

Haha yeah that's what my mechanic was saying, when I bought my car the guy did an " i " chip and he never swapped out the manifold or throttle body.

What is the benefit of the I throttle body and manifold?

[nando]

more airflow. doesn't get much more straightforward than that. :D

the eta manifold is meant for low RPM use where the engine's peak power is near ~4000rpm. It builds up velocity fast but it can't flow as much air. that's why the eta's torque is higher than a B25 while the HP a lot lower (the head is part of it too but it's not the only reason).

[Suspence]

Gotcha, so more air flow = more power.

I'm hoping that the manifold will make a big difference, on top of new heavy duty rockers, I throttle body and Miller MAF. O yeah and 272 Regrind...

With the 272 regrind do I need anything else besides the cam itself?

[nando]

you will need oversized eccentrics, and I'd reccomend replacing eccentric nuts/bolts and possibly the rocker clips. check the side to side play of your rockers and see if any clips are bent or lost some of their shape.

[Suspence]

you will need oversized eccentrics, and I'd reccomend replacing eccentric nuts/bolts and possibly the rocker clips. check the side to side play of your rockers and see if any clips are bent or lost some of their shape.

Since it's the 272 regrind, I will most definitely need oversized eccentrics? Where is a good place to buy them?

-Spencer

[einstein57]

I know ireland sells them

[digger]

I'd like to see more work done with a custom manifold taking runner length vs. plenum volume vs. port size into consideration, but I don't realistically see anyone(or company) going out their way to do this without more market demand. At least, not on an NA m20. Unless you're a die hard m20 fan, there's no point in trying to find that extra hp. The R&D needed would be expensive without the tools/fab skills/machining equipment, and knowledge, readily available to you. The only alternative I've considered is converting to a triple-carb setup. Like the kind that were/are available on the old TR6.

by deviating from the B25 one there seems to be some rather compromises in order to make decent improvements.

[Suspence]

I looked on the IE website and they don't have anything, guess I'll have to call. How much would you guess that they run a piece?