SBC intake manifold dyno comparison.

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SBC intake manifold dyno comparison.

Post by Walter R. Malik » Sun Feb 09, 2014 9:11 pm

An acquaintance showed me a dyno test recently done with a 23 degree "Raised Runner" small block Chevrolet 383 street/strip engine with GM #101 heads.
The comparison tests I saw were between two Edelbrock manifolds; the Older Victor Jr. High Port #2967 and the newer Super Victor #2926. Both are supposed to have the same area runner with the later being taller so a bit longer. Both were "out of the box" other than a port match.
These tests showed the Super Victor LOSING 18 lb/ft of torque to gain 5 horsepower and 200 RPM.
Just out of thought, I would think that the taller, longer manifold would have MORE torque; (if they are indeed the same cross sectional size), so, what's going on...?
Needless to say he was disappointed with his NEW intake manifold.

The cam was not huge 259/266@.050" solid flat tappet around .600" lift.
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Re: SBC intake manifold dyno comparison.

Post by bigjoe1 » Sun Feb 09, 2014 9:21 pm

In manifold tests I have seen, many times will require a jet change with the new manifold


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Re: SBC intake manifold dyno comparison.

Post by Walter R. Malik » Mon Feb 10, 2014 12:35 am

bigjoe1 wrote:In manifold tests I have seen, many times will require a jet change with the new manifold


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These were the best numbers with several runs of each manifold optimized for ignition timing and fuel. That is one of the reasons this is so baffling to me.
Not knowing any real reason why, lead me to ask about anybody else' similar results.
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Re: SBC intake manifold dyno comparison.

Post by GARY C » Mon Feb 10, 2014 2:48 am

Years ago I contacted a well known engine builder about a standard 23 degree headed 350 I was building, he recommended a Victor high port cut to fit the standard runner head or order a Gm Bowtie, I bought the Bowtie and found it was a raised runner cut to fit a standard head.

I told the engine builder that I had a Super Vic and he told me I would probably be down on power by 20 ft lbs and 20 horse, when I asked him why he told me to look in the plenum and keep in mind that air has to turn corners and that the runner extensions hurt more than help in most cases.

I later found out that this engine builder has won engine masters and consistently finishes in the top 5 including last year.

The Edelbrock book shows the two intakes you referenced at 2.80 cross section

It would have been interesting if your friend had tried the super vic with the runner extensions cut back.

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Re: SBC intake manifold dyno comparison.

Post by JoePorting » Mon Feb 10, 2014 3:45 am

Maybe the new manifold ports didn't line up right. Did you check the port alignment with a flashlight down the carb pad? Sometimes you have to mill down the intake surfaces to make the ports line up right if the manifold is too high, or use thicker intake gaskets to raise the manifold if it is too low.

Also, I believe the 2926 is a larger manifold while the older Victor jr is smaller. That might explain the loss of low end torque and increase in rpm and high rpm hp with the larger 2926. The 2926 is probably more suited for a 400+ SBC motor.
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Re: SBC intake manifold dyno comparison.

Post by jmarkaudio » Mon Feb 10, 2014 9:36 am

Maybe the runner extensions hurt distribution. One of those thing having 8 O2's on a dyno might find.
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Re: SBC intake manifold dyno comparison.

Post by CREngines » Mon Feb 10, 2014 9:50 am

On a test i ran on a super victor and victor Jr on the same 23 std port engine, it did exactly opposite of what they are saying in this magazine.

It is a magazine, and as we all know, just because its printed on paper doesnt mean a damn thing.
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Re: SBC intake manifold dyno comparison.

Post by WeingartnerRacing » Mon Feb 10, 2014 6:05 pm

Probably because the Super victor looks like shit out of the box.
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Re: SBC intake manifold dyno comparison.

Post by Walter R. Malik » Mon Feb 10, 2014 10:28 pm

WeingartnerRacing wrote: Probably because the Super victor looks like shit out of the box.

Could be, LOL.
I didn't see the actual manifold however, this guy didn't just fall out of the back of the turnip truck; he does know what he is doing.

There was nothing wrong with his engine ... he just took it out after 20 years to get it apart to check everything and figured he would update the intake manifold at this time.
It is in a really nice mid 80's Monte Carlo.
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Re: SBC intake manifold dyno comparison.

Post by Greenlight » Tue Feb 11, 2014 12:30 am

I know I haven't looked at as many Super Victors as some of you, but I recently had two new Super Victor manifold on my flow bench and noticed that the casting transition from the plenum to all of the runners had a very sharp, well defined line there. It is kinda' visible in the generic photo I found on Al Gore's internet. This may be the source of the poor performance. These casting may vary by production run, but these were the worst I have ever seen. I haven't looked at a new Victor Jr. in many years, but I don't remember them being this bad. All/most intakes require some amount of work in this area to improve that transition.

Image

Walter, have your friend that a cursory look at this area on both manifolds and give us some feedback.
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Re: SBC intake manifold dyno comparison.

Post by JoePorting » Tue Feb 11, 2014 12:31 am

WeingartnerRacing wrote:Probably because the Super victor looks like shit out of the box.
Have you ever noticed how the #8 port on the #2925 is off by .250". It's so off that when you try and match port it to a Felpro 1206, about .100 of the port is off the gasket. I think it's been like that since the beginning. You'd think Edelbrock would have fixed the tooling by now.
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Re: SBC intake manifold dyno comparison.

Post by steve cowan » Tue Feb 11, 2014 3:01 am

i have a 383 with a super victor cnc intake and i was lucky enough for port match to my 215 pro1s with minimal work but i did have to spend a couple hours around plenum area,i have a victor jr and a victor e here that i checked out around plenum there is a big difference but i dont know about the raised victor jr,i spent a lot of time just to get the victor jr to fit my standard port dart cast sportsman 2 heads with a 1205 gasket,i really dont think we are comparing apples with apples as the super victor is more suited to bigger cubic sbc or a higher rpm application 383-400,my junker has a 254-260 deg roller with 680'' lift 11.0:1comp makes 525@6800rpm but i think the intake is to big as i dont turn it hard enough(2 bolt mains)so i am seriously considering going to a rpm air gap as i do a fair bit of street driving and i would not be surprised if it still made 510

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Re: SBC intake manifold dyno comparison.

Post by Walter R. Malik » Tue Feb 11, 2014 9:42 am

The "Raised Runner" manifolds inner geometry is different than their normal height intake manifolds; at least that is what Edelbrock claims.
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Re: SBC intake manifold dyno comparison.

Post by Walter R. Malik » Tue Feb 11, 2014 9:44 am

Walter R. Malik wrote:The "Raised Runner" manifolds inner geometry is different than their normal height intake manifolds; at least that is what Edelbrock claims.
The engine is going back into the car with the High Port Victor Jr. and he will sell the Super Victor "to some other unsuspecting soul" ... his words.
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Re: SBC intake manifold dyno comparison.

Post by BOOT » Tue Feb 11, 2014 10:03 am

Was he using any spacers? Or did you try any on either intake?
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