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PostPosted: Sat Nov 25, 2017 7:13 am 
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Location: Huntsville, AL
I would be interested in seeing actual data as to the drop in IATs with ducting to and shrouding the intake manifold, considering the air inside the manifold is being replaced hundreds of times a second with fresh air anyways. I have no dog in the rule argument. I supposed on a non crossflow head there could be some benefit in keeping the intake from being heated by the headers.

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PostPosted: Sun Nov 26, 2017 7:53 pm 
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Have I missed something about allowing Weber DCOE's on Prod cars? And I looked on Pierce Manifolds website and do not find a J15-1952.


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PostPosted: Mon Nov 27, 2017 3:30 am 
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Location: Just south of Indianapolis
Jerry,

For the 1500 in LP HP trim it's not a DCOE that's allowed but a DGV/DGAV downdraft. The allowance has been there since 2008. The J15 manifold isn't sold separately as that part number but that is the casting number on the manifold for the DGV that sold in the pierce kit.

The allowance for the DGV/DGAV was a carry over from the original LP rules which allowed any single carburetor car to switch to a DGV/Holly 5200 etc. The spitfire 1500 was a single carb'd car but is the only (or one of the only) single carb'd car that is a side draft configuration. So the allowance for the full alternate intake manifold was asked for.

I was the original requester for the manifold, when they gave the hybrid prep 1/2 for the 1500 they didn't carry over the 1500 engine specs correctly.

aaron

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PostPosted: Mon Nov 27, 2017 6:01 pm 
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Nope. The manifold authorised by the spec line is this one.

http://www.piercemanifolds.com/product_ ... 807PM.html

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PostPosted: Tue Nov 28, 2017 11:57 am 
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Brett W wrote:
I would be interested in seeing actual data as to the drop in IATs with ducting to and shrouding the intake manifold, considering the air inside the manifold is being replaced hundreds of times a second with fresh air anyways. I have no dog in the rule argument. I supposed on a non crossflow head there could be some benefit in keeping the intake from being heated by the headers.


On my non crossflow VW with ceramic coated headers but no other heat shielding the intake does get pretty warm, never measured it though.

I've done some rather feeble Googling for some actual test data relating charge heating or power to manifold temp and have not found anything so far. My gut tells me that the power impact is small but that's a guess. It would be pretty easy to test on a chassis dyno using a 5lb bag of ice!

I'm too lazy to haul out the textbooks and do a real heat transfer calculation!

Anyone ever see any numbers?

Your statement makes me think though - considering the volume and velocity of air moving inside the manifold, it does not seem likely that blowing some (surely much lower velocity) air at the outside would actually do much. The biggest impact would surely come from putting a decent heat shield on top of the headers.


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PostPosted: Tue Nov 28, 2017 12:09 pm 
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Al Seim wrote:
The biggest impact would surely come from putting a decent heat shield on top of the headers.


Or stop using tractor motors that have the intake or exhaust on the wrong side. :lol:

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PostPosted: Tue Nov 28, 2017 8:39 pm 
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Al
Smokey Yunik had good results heating fuel to achieve better atomization.
Wonder if the same might work for you.
FWIW

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PostPosted: Wed Nov 29, 2017 7:11 am 
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FIAT90FP wrote:
Al
Smokey Yunik had good results heating fuel to achieve better atomization.
Wonder if the same might work for you.
FWIW


Kinda need to add boost to make his ideas work. I can't imagine what happens if you tried to boost a three main British block.

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PostPosted: Wed Nov 29, 2017 7:36 am 
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Brett W wrote:
FIAT90FP wrote:
Al
Smokey Yunik had good results heating fuel to achieve better atomization.
Wonder if the same might work for you.
FWIW


Kinda need to add boost to make his ideas work. I can't imagine what happens if you tried to boost a three main British block.

Smoke, oil, fire, metally bits on the ground....so status quo, really. :lol:



(Oh come on, it's a joke!)

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PostPosted: Wed Nov 29, 2017 8:10 am 
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David Vizard managed a 22% HP increase using a turbo, and a 41% HP increase using a Roots type, on a 1275 BMC. British Leyland put a turbo on the Metro and INCREASED the compression ratio (to help fuel efficiency)

Unlimited budget I suppose.

No mention of reliability. (Roots type used on drag racer)

Interestingly, venturi shape changes significantly over naturally aspirated, to make carbs boost sensitive as well as velocity sensitive.

RJS


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