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Old 04-30-2008, 06:58 PM   #1
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I have 94 heads and intakes on my Vin C. I gasket matched the LIM to the heads. They transition smoothly into eachother and I did not alter the top of the LIM there there injector sprays in. I read a post somewhere i forget, but they said not to gasket match the ports. Am I going to get any nasty surprises when I get it all back together?
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Old 04-30-2008, 07:14 PM   #2
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if you gasket matched to port, then you overported. you have now created turbulance from the LIM ports being larger than the head ports.
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Old 04-30-2008, 07:18 PM   #3
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So you opened up the LIM and heads to the gasket?

One reason you wouldn't want to open them up that far is if the cross sectional area of the LIM exit is larger than it'* inlet. That will slow the air down since the cross section goes small big and then small at the coke point in the head.
I couldn't tell you if that LIM keeps the same cross sectional area but I know the L36 LIM decreases about 30% to ramp up velocity. I would expect something similar on an n/a engine.
There'* also the possibility of opening it up too much and loosing velocity.. But your not going to know if that will be the case for sure until you try it out.
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Old 04-30-2008, 07:20 PM   #4
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I test fitted it and the transition between the LIM and the heads is barely noticeable. Will this still cause turbulence?

edit: I didnt have to open the heads up that much, I tried to keep the LIM runners and the intake of the head as flat as possible. The series 1 runners have a much more gradual slope leading into the head. I hope I didnt over do it. But it cant be any worse than what was in there could it?
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Old 04-30-2008, 07:24 PM   #5
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Quote:
Originally Posted by phoenix_flame220
I test fitted it and the transition between the LIM and the heads is barely noticeable. Will this still cause turbulence?
yes. but the question is how much? i dont know

but if just the rough casting causes turbulance, than think of how that overporting will affect it.
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Old 04-30-2008, 07:26 PM   #6
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if you opened the heads too, then you have a better chance of reducing the turbulance of overporting.

did you measure with a micrometer? or just gaskets?
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Old 04-30-2008, 07:31 PM   #7
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I just went to the gaskets, but I made sure that the gaskets were a little recessed so they didnt affect the flow. The only place it isnt smooth is there the injector is. Theres a bit of a step down into the head because I didnt want to screw up the injector tuning. I blended in the exit of the runners about 1.5 inches to make sure there were no bumps or divets. I think itll be ok, but I got a little concerned when I read that comment.
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Old 05-01-2008, 12:01 AM   #8
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If you ported the heads with your mods (none), you lost port velocity. That'* the simplest view. You shouldn't have ported the heads at all. No benefit, and a couple negatives.
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Old 05-01-2008, 01:41 AM   #9
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What necessary additional mods are available to make the porting worthwhile? Otherwise how would he make what he has already done, useful, instead of negatively affecting performance.
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Old 05-01-2008, 08:59 AM   #10
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CAI, high-flow cat, and 1.8 ratio rocker arms.
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