C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

383 - Breathing Issues

Old Jun 5, 2012 | 09:04 PM
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Default 383 - Breathing Issues

I have a 383 with ported TPI that is serving me well except it's not getting enough air into the plenum. I see a wide variety of ram air / cut lid / filter replacement mods. Forward of the TB I've only replaced the filter with K&N.

Any suggestions/recommendations?

Thanks!

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Old Jun 5, 2012 | 09:22 PM
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What makes you think its not getting enough air in the plenum?
How far did they go on porting?(runners base plenum etc?)
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Old Jun 5, 2012 | 10:29 PM
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Ported the plenum, SLP Runners and the TPIS Big Mouth intake. Heads were also port matched and I've got Melrose Headers to 3" exhaust to Magnaflow Mufflers. The builder advised me that I had a bottleneck at the air intake.
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Old Jun 5, 2012 | 10:37 PM
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If your builder is right (and that has not yet been confirmed), the bottle neck would be the stock MAF.

Put a GOOD vacuum gauge on it. Run it from idle to fuel cut/Redline at WOT. If you see ANY vacuum at all, your builder is right. If not, he is wrong. If you have atmospheric pressure in the plenum at WOT, there is no restriction ahead of the plenum. (TB, MAF, tube, filter housing or filter).
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Old Jun 5, 2012 | 10:45 PM
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Originally Posted by jwheelerjr
The builder advised me that I had a bottleneck at the air intake.
What brought him to that conclusion?
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Old Jun 5, 2012 | 10:56 PM
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Then the stock heads

The TPI style intakes will only go so far up in the rev range if thats what youre wondering.
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Old Jun 5, 2012 | 11:14 PM
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Went with new heads as well. It made sense to me that with the changes I'd have to do more for air flow but the car runs well enough.
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