Which Intake Manifold is better performance wise?

D15, D16, D17 and Mini-Me swaps
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By Ajax1989
- Thu Apr 15, 2010 8:48 pm #188013 the y8 is better, the plenum and the runners make it one of the best if not the best IM..stock wise

aftermarket theres
edelbrock
skunk2
blox
:thumb:
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By teal_dx
- Fri Apr 16, 2010 3:15 am #188098 The Z6 is supposed to be better flowing at very high RPM while the y8 is better flowing throughout more of the RPM range used for most driving.

This is what I have read, I'd love to see a flow test comparison to settle once and for all.
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By robster
- Fri Apr 16, 2010 5:11 am #188110 If you run a bigger TB i whould say y8 and with a stock TB a z6!

If you'r handy with porting i whould recommend a ported z6 with a 2mm step at the TB inlet that works as a anti reversion step.
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By forcefedEG
- Fri Apr 16, 2010 12:33 pm #188136
teal_dx wrote:The Z6 is supposed to be better flowing at very high RPM while the y8 is better flowing throughout more of the RPM range used for most driving.

This is what I have read, I'd love to see a flow test comparison to settle once and for all.


x2 that says it all
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By suspendedHatch
- Fri Apr 16, 2010 3:08 pm #188167 Because the head designs and engine tuning are so different, it's actually true that the Y8 intake manifold is best for the Y8 head and the Z6 intake manifold is best for the Z6 head. Swapping them makes a small but negative difference to the overall curve. I know because I used to be able to get my car dyno'd after hours and I tried lots of different things (tried a Y8 mani on a SOHC ZC). Many of the things I tried, ie B18 throttle body, swapping intake manifolds, advancing timing, increasing fuel pressure; all resulted in a net loss in power.

It was disheartening at the time because it seemed like everything I did only hurt power output. But I learned that you can't just take advice online and slap parts on an engine and expect to get a positive result.

The Y8 head was designed to bring the power band down into the usable range, resist detonation, and require less timing advance. The Z6 was designed to get a high hp spec. Look at the difference in quench area, size of valves, size and shape of ports, length and diameter of intake manifold runners, size of plenums, and cam lobe specs. If you swap the manifolds, you are fighting the engineers intentions.

Peak hp is overrated.

By mregcivic
- Fri Apr 16, 2010 8:14 pm #188238 wow thanks. so i might just go with the z6 manifold n test it out.
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