o-rings and aftermarket intake manifolds

[skywings]

Hey guys. Just wondering if someone could explain to me what o-rings are, where they are done on the engine and what they do.

Also, I've seen some aftermarket intake manifolds and am wondering how these really square looking things can improve flow compared to the smoother looking stock stuff. Anyone?

http://store1.yimg.com/I/racerwheel_1812_20581884

[bennjamin]

O rings are rubber grommets , used to fill a gap in a connecting part in a motor - such as the injectors , spark plug gap etc etc.
They need to be replaced every so often - as rubber isnt as durable as the rest of the alloy block.

That square inlet manifold - would only benefit max power at hi rpms . Stick with stock inlet designs ( there is a reason Honda designed them liek that) and port entires and exits...and clean etc for more free flow.

[wynode]

short intake runners are usually used for good high RPM power as said above :)

[Weq]

the reason they are boxy is to promote even flow into all cylinders.. there is a huge science behind intake manifolds, i wont pretend to know, but use google.

[PhatSol]

I've seen dyno results for those things, and it seems that manifolds like the Venom and the STR only start beating the stock B16A manifold at 9-10krpm.

[J_Mech]

I think its square because that the aluminium extrusion they used for it, which gives about the right plenum volume (if they worked that out - ball park figures are about 80% of the motor swept volume).

I always have my doubts wether side intake manifolds give some kind of even flow through each intake runner, through out the rev range (although the packaging is excellent). I guess if they have simulations to back something like that up i'll beleive it - I prefer the original ones. The runners on this one look shorter than standard so the volumetric efficiency of this design will peak at a higher rpm.

What ive heard, and what can be done is buy another stock intake manifold from the wreckers and cut the runners off it and weld in new shorter runners, you will have the smoother plenum chamber with shorter runners giving more torque at higher rpm.

J_Mech

[skywings]

Great. Thanks for the info, guys. Looks like stock for me! Although, I was also wondering if there is an advantage to intake manifolds similar to stock like JG Edelbrocks. Or is the expense not worth it, really?

[DynoDave]

Great. Thanks for the info, guys. Looks like stock for me! Although, I was also wondering if there is an advantage to intake manifolds similar to stock like JG Edelbrocks. Or is the expense not worth it, really?

A performance intake manifold will make a small gain on a STD engine but to take full advantage of it you will need to do other mods as well, what engine do you have in your car as then we will be able to give you a better idea of what to look for if you want to upgrade.
Regards Dyno Dave

[skywings]

got a B18A1 stocker at the moment. got a B18C1 head sitting in a box too. doing some research as to what to do and buy. want to keep it all motor.

[pornstar]

most important thing ti consider tho, is the internals of the mani, not the external :)