Crawford Billet Power Blocks

[sidesleeper]

Originally Posted by celek

not my reality, it is simple physics and velocity. You see the same thing in the Honda world with the Acura GSR that has 2 different length runners and a butterfly valve to divert air flow to a shorter runner at a specified RPM for high horsepower.

The longer runners provide more TQ while the shorter runners provide less TQ at higher RPM resulting in more top end.

This is why the Type R has a really short straight runner for more top end but not as much TQ because its designed for road racing and staying in a Power band when it was a Spec car in the late 1990s.

Same can be achieved on the exhaust manifold.
https://www.physicsforums.com/thread...eaders.208674/

Same can be seen here in Lemans cars ITBs.
https://grassrootsmotorsports.com/fo...s/58727/page1/

The Crawford BPB have been proven by numerous 3rd party reputable sources who originally doubted the claims. If you had a different experience you may want to find a different tuner for the VVC maps and Injector timing since they have been moved up slightly.

Originally Posted by stugray

His "perception" IS REALITY, therefore it is your reality too.
(unless you live in an alternate universe).

Perhaps what you meant to say was "My observations do not match your explanation"

Negative, this is not reality... this is a forum and he skirted around the most important thing I mentioned. He seems to be mired in the fluid dynamics of why it is supposed to work, which isn't the point at all.

You just added more thermal mass to the engine. Bottom line is they heat soak, which effectively decreases knock threshold due to thermal transfer to the intake charge, which in turn will cause the engine to knock and cause the ECU to pull timing, hence making the vehicle slower.

The examples you give are of engines that breathe, the FA20 does not.

I didn't see any reputable empirical data from 3rd party sources.

You can sit here and spin it anyway you want, that's what makes a good snake oil product.

[steve99]

Here is 3rd party testing on BPB.

http://www.ft86club.com/forums/showthread.php?t=62007


skip to summary at end

great on stock cars with good fuels
shift power lower in rpm range
benifits deminish as other mods added and tunes
not much good with E85 as they newter power over 6000 rpm

[Impureclient]

Concerning the heat soak issue. Why aren't these made from plastic?

[steve99]

Originally Posted by Impureclient

Concerning the heat soak issue. Why aren't these made from plastic?

Im not an expert on manufacturing costs but I believe its quite expensive to set up moldings ect for doing injection molded plastic parts. So you have to do runs of many thousands.

for small production runs was probably cheaper to get it milled from aluminum.
and it looks the goods and people are happy to pay a few hundred bucks.

People would probably arc up paying that sort of money for a piece of plastic.

[celek]

Originally Posted by steve99

Im not an expert on manufacturing costs but I believe its quite expensive to set up moldings ect for doing injection molded plastic parts. So you have to do runs of many thousands.

for small production runs was probably cheaper to get it milled from aluminum.
and it looks the goods and people are happy to pay a few hundred bucks.

People would probably arc up paying that sort of money for a piece of plastic.

Yes because a mold for injection can run you $5k-$10k or more
Also because the left and right manifold flanges are not identical resulting in 2 molds.

[celek]

Originally Posted by steve99

Here is 3rd party testing on BPB.

http://www.ft86club.com/forums/showthread.php?t=62007


skip to summary at end

great on stock cars with good fuels
shift power lower in rpm range
benifits deminish as other mods added and tunes
not much good with E85 as they newter power over 6000 rpm

Also
http://www.ft86club.com/forums/showthread.php?p=1784979
http://www.ft86club.com/forums/showthread.php?t=62471
http://www.motoiq.com/MagazineArticl...d-Spacers.aspx

[stugray]

Originally Posted by Impureclient

Concerning the heat soak issue. Why aren't these made from plastic?

Originally Posted by steve99

Im not an expert on manufacturing costs but I believe its quite expensive to set up moldings ect for doing injection molded plastic parts. So you have to do runs of many thousands.

for small production runs was probably cheaper to get it milled from aluminum.
and it looks the goods and people are happy to pay a few hundred bucks.

People would probably arc up paying that sort of money for a piece of plastic.

Originally Posted by celek

Yes because a mold for injection can run you $5k-$10k or more
Also because the left and right manifold flanges are not identical resulting in 2 molds.

So if you are all setup to machine them out of Aluminum, why not start with a block of plastic instead?

[Spartarus]

Originally Posted by stugray

So if you are all setup to machine them out of Aluminum, why not start with a block of plastic instead?

Machined plastic doesn't hold pressure as well as injection molded plastic, especially as you heat it up. Also I've never found a bit or speed setting that doesn't melt the edges of the plastic, but I haven't tried so hard.

Related note, Injection molds are PRICEY. Making two, you might as well mold a whole new manifold, and the kindly people at Velox have already discovered that's prohibitively expensive.

[celek]

Originally Posted by stugray

So if you are all setup to machine them out of Aluminum, why not start with a block of plastic instead?

Because the correct plastic to use is more expensive than aluminum and aluminum is more readily available locally
https://www.interstateplastics.com/D...ss=1.000&qty=1

http://www.grainger.com/product/GRAI...Code=P2IDP2PCP

[steve99]

Originally Posted by Spartarus

Machined plastic doesn't hold pressure as well as injection molded plastic, especially as you heat it up. Also I've never found a bit or speed setting that doesn't melt the edges of the plastic, but I haven't tried so hard.

Related note, Injection molds are PRICEY. Making two, you might as well mold a whole new manifold, and the kindly people at Velox have already discovered that's prohibitively expensive.

And unfortunatly the velox manifold provided no usefull gains on an NA motor and i suspect the fullblown intake manifold may be same NA, maybe they work FI ?

[DJCarbine]

Originally Posted by Spartarus

Machined plastic doesn't hold pressure as well as injection molded plastic, especially as you heat it up. Also I've never found a bit or speed setting that doesn't melt the edges of the plastic, but I haven't tried so hard.

Delrin machines good, never had a problem working it on the lathe/mill

Tends to snipe depending on how aggressive you are, and drilling it with large bits can be a pain

[celek]

Originally Posted by steve99

And unfortunatly the velox manifold provided no usefull gains on an NA motor and i suspect the fullblown intake manifold may be same NA, maybe they work FI ?

Because their math was wrong and the inlet was TOO big.
The stock ports in this head for NA purposes flow too much they went with a 54mm Inlet which is 4% larger than needed for stock flow, On top of that they put a velocity stack on an opening too large for a port design that already flows too much for stock.
People have had better results restricting flow in the ports of the head with epoxy which builds up more velocity producing more power.
Really odd reverse porting works better.
Velox Might as well of not put a manifold on to begin with basically same result.

FI it will work because forced air.

[Spartarus]

Originally Posted by DJCarbine

Delrin machines good, never had a problem working it on the lathe/mill

Tends to snipe depending on how aggressive you are, and drilling it with large bits can be a pain

Never thought of Delrin, I've had good success milling components for watercooled computers out of it, but the melting point is way too low. I wouldn't bolt it straight to intake ports on a cylinder head.

Was talking about the polyamides and others with lower rockwell and higher melting point / deflection temperature. Hard to machine that sh*t.

[steve99]

Originally Posted by celek

Because their math was wrong and the inlet was TOO big.
The stock ports in this head for NA purposes flow too much they went with a 54mm Inlet which is 4% larger than needed for stock flow, On top of that they put a velocity stack on an opening too large for a port design that already flows too much for stock.
People have had better results restricting flow in the ports of the head with epoxy which builds up more velocity producing more power.
Really odd reverse porting works better.
Velox Might as well of not put a manifold on to begin with basically same result.

FI it will work because forced air.

Makes sense especially if the same heads valves ect used on the forester and wrx turbo motors was probably optimised for that