rpm airgap or Lt1 highriser ?
05-23-2004, 10:23 PM
#1
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rpm airgap or Lt1 highriser ?
Am currently running an al. highriser from a 70' Lt1 and was thinking
about a switch to an RPM airgap. My engine is a strong runner with aprox.
400 flywheel hp and was wondering if i will see enough of a difference to warrent the change.
thanx wade
about a switch to an RPM airgap. My engine is a strong runner with aprox.
400 flywheel hp and was wondering if i will see enough of a difference to warrent the change.
thanx wade
05-23-2004, 10:56 PM
#2
Re: rpm airgap or Lt1 highriser ? (wadey)
Doubtful. Of course, for some folks like Stock Eliminator racers, 5HP is worth large amounts of time and money. I doubt if you are that far gone though. Also not sure there is any gain to be had at all, but it would be interesting to find out.
If you do it, it would be a public service to do before-and-after chassis dyno runs.
If you do it, it would be a public service to do before-and-after chassis dyno runs.
05-24-2004, 06:30 AM
#4
Safety Car
Re: rpm airgap or Lt1 highriser ? (wadey)
They are, for the most part, about the same manifolds except the Air Gap will allow the runners to be cooler. Aluminum is a great heat conductor and even with a blocked heat crossover, the LT1 manifold gets a pretty good heat soak from just conduction. But as to the question about replacing an exceptional manifold with about the same thing -no real gain and certainly nothing you'd be able to feel.
05-24-2004, 10:13 AM
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Re: rpm airgap or Lt1 highriser ? (wadey)
More info. would be better as far as whether you might want to change like trans., carb CFM & winter driving.
Some of us have been running heat shields under the intake for many years.
Some of us have been running heat shields under the intake for many years.
05-24-2004, 02:06 PM
#6
Le Mans Master
Re: rpm airgap or Lt1 highriser ? (Ganey)
My LT-1 dyoned on a good engine dyno (DePac data aquisition, just like the NASCAR boys use) showed a 4HP increase by changing from a LT-1 production manifold to a Perfromer RPM (not the "air-gap".) I would give a "air-gap" another 4-6HP over the RPM because of the more open plenum divider but, no more than 12HP over a factory intake. Edelbrock claimed in their catalog that the RPM was worth 19HP over an LT-1 intake, they have some poor data aqusition methods in their dyno cell compared to my friend's GH490 Froude with DePac 32 channel real time data aqusition. Super Flow dynos are "toys" in comparison to my friends dyno, even Edelbrocks GH490 Froude with Digilog data aqusition is not as reliable/repeatable as my friends dyno. 19HP my a** maybe if you add up all your RPM points and 2-3HP increases at these testing points you will see 19HP but not at any part of a 2500-7000 RPM curve did we see 19HP better with the RPM manifold over the factory intake on my LT-1. Don't believe everything you read!
