Larger Runners--Some Questions
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Pro
Joined: Mar 1999
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From: Fair Oaks CA
Larger Runners--Some Questions
At this point, I'm guessing that "runners" are the large aluminum tubes that run form the plenum into the engine. Right now I have the stock units for my 89, and I'm wondering if installing a larger pair would be worth it. The brand I've heard of is made by Arizona Marine.
So what would larger runners do for me?
What sort of related changes would I have to make in addition to installing the runners?
Thanks in advance,
-WL
So what would larger runners do for me?
What sort of related changes would I have to make in addition to installing the runners?
Thanks in advance,
-WL
Pro
Joined: Dec 2001
Posts: 715
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From: NYC NY
Re: Larger Runners--Some Questions (White Lightning)
Larger runners help to support more horsepower by letting the engine breathe better at hihger rpm's. A standard tpi setup is fairly restrictive, which is why you see the power drop of at 5400 rpm's or so. Larger diameter runners will can help here, but in order to take full advantage of larger runners you will need to port the manifold and/or the plenum.
Thread Starter
Pro
Joined: Mar 1999
Posts: 560
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From: Fair Oaks CA
Re: Larger Runners--Some Questions (C4-Wolf)
I've had my plenum ported to the stock runners, so I'm thinking I'd have to have it re-ported to the larger runners (if I get them).
Where would the power increase occur? Seems like only at the upper RPM range.
Should I get a larger TB as well?
Thanks,
-WL
Where would the power increase occur? Seems like only at the upper RPM range.
Should I get a larger TB as well?
Thanks,
-WL
Burning Brakes
Joined: Feb 2000
Posts: 1,247
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From: Parker, Colorado, USofA
Re: Larger Runners--Some Questions (White Lightning)
Having replaced the manifold base and put a Superram on an otherwise stock motor (for a month while the other motor was built) I can tell you that the gains you'll see are minimal. The stock manifld base was designed for a 305 cu. in. application and it's got limits to how much porting can be done with the stock casting.
The Accel/LPE casting supports much higher flow, but what I really saw was: The car didn't pull any harder, it just pulled LONGER. Rather than giving it up at 4500-4800 rpm, it'd pull all the way to 6000 and grab scratch shifting to 2nd.
So you MAY end up being able to pull to 5000-5200 efficiently but you may also be disappointed if you change nothing else.
The Accel/LPE casting supports much higher flow, but what I really saw was: The car didn't pull any harder, it just pulled LONGER. Rather than giving it up at 4500-4800 rpm, it'd pull all the way to 6000 and grab scratch shifting to 2nd.
So you MAY end up being able to pull to 5000-5200 efficiently but you may also be disappointed if you change nothing else.
