[Larry Navarro]

Very interesting info but not necessarily limited to "street" cars.
Use "zoom" feature to enlarge the pic for your reading pleasure.

[Steve C.]

"The large L92 intake ports do give up some torque at lower engine speeds because of their size, but the peak flow and subsequent peak horsepower numbers are so good, give the GM enginers and their management team a big thumbs-up for producing such outstanding cylinder heads."

From a recent article about testing with these new heads that flow 320 cfm right out of the box.... on a 550 hp 364 cubic inch engine that was tagged as "very streetable".

Again somewhat related. Another quote from a very notable Pontiac person.....

"If you are satisfied with your 467 cid engine running out of breath at
5,200 rpm., by all means, keep your 176cc. ports. If you want to go
faster, more air is required. 176cc. ports on a built 500+ cid. engine
is just as ridiculous as a 250 cc. port on a hydraulic flat cam 400 cid.
engine."

[uneasyrider]

That's the topic that comes up when the 351CJ heads gets talked about, for example. Most feel the port size was way to big for street use because the velocity wouldn't be high enough for normal street driving.

[speedshopmike]

what's the point?
this isn't a new notion by any stretch of anyone's imagination.

[Larry Navarro]

Originally Posted by Steve C.

..........if you want to go
faster, more air is required. 176cc. ports on a built 500+ cid. engine
is just as ridiculous as a 250 cc. port on a hydraulic flat cam 400 cid.
engine."

hmmm,
About six years ago, the 165 to 170cc ports on a well known "SUV" of over 4000lbs., ran 11.40-11.50's, with street gears of a 3.55 or 3.31 ratio.
This particular vehicle has dipped well into the 11.30's with a 473cid engine, rather mild flat tappet hydraulic cam and "tiny" 165 cc ports. Of course, it is shifted at a "street RPM" and doesn't need to rev up to 6300PRM or more, to obtain reasonable performance!

This is just simply ridiculous!!

[Steve C.]

Yes he did.

[gearbanger]

Theirs alot of "street cars" with slicks and a suspension set up for drag racing that will run 11.50s. And with a whole lot less than 473 cubic inches. It is very deceptive and frankly kind of getting old calling that car a street car. It is big a$$ drag car with a big a$$ street engine in it.

[INJUNTOM]

ok, where's the rest of the article?

[Steve C.]

Port Volume - Page 77 and 78

[Skip Fix]

Larry as you said when I brought up other heads showing different power bands with the SAME size port-"same discussion beating a dead horse".

So if the same size heads can have different power bands how do you know it's just the head cc??? You can't. It's also why the big guys have gone to wet flows-same sized heads flowing similar making less power.

[Half-Inch Stud]

"Wind it up, Blow It (the bottom) Out Gee TEE Ohhhh"

[gjn]

Originally Posted by gearbanger

Theirs alot of "street cars" with slicks and a suspension set up for drag racing that will run 11.50s. And with a whole lot less than 473 cubic inches. It is very deceptive and frankly kind of getting old calling that car a street car. It is big a$$ drag car with a big a$$ street engine in it.

I have seen this car in person and it is the second most impressive car I have ever seen. It could be a daily driver, runs 11.50s at 115 mph and wieghs in at over 4,000 beans. And BTW, it is a quiet car with full exhaust too. Show me a car that weighs as much, with a 3.23 gear, full exhaust, hydralic cam with a good idle, Q-jet, D-port heads on pump gas and I will listen. As far as expensive, it's really not. His combo has been tuned through the years by trial and error; but, it's not like he bought a set of ported eldebrock heads or anything.

[Cliff R]

We've managed to run mid 11's in full street trim for several seasons now, on 89 octane fuel in our daily driven car. Full/quiet exhaust system, stock type idle quality, iron intake, q-jet, 3.42 gears, 10" converter, no traction bars of any kind, on DOT tires. It took us several years to get there.

When we first installed the 455 engine, it ran 12.90's. We've tweaked and tuned it all the way to 11.50's, and that was with the DA up near 4000'. The biggest gains to performance were NOT from the engine. The fuel system was by far and above the biggest improvment. We also saw a couple of tenths going from 2.5 head pipes to 3" with a custom "H" pipe between them. The KRE heads were worth a solid two and a half tenths and 2mph.

The most recent improvment was from a custom HR cam with specs based on the RAIV grind. We've only been out 3 times with it, but it's already running quicker in hot/humid weather than we ran in near perfect conditions with the flat RAIV grind.

Folks, running this quick just doesn't fall in your lap when you install a big high torque engine. It's about the combination of parts, the engine is simply part of a well thought out plan. Sometimes, as it did with us, it may take several years to figure out all the fine details to get everything working together for really quick runs......and did I mention parts breakage? To date we have broken EVERYTHING behind the engine, at least once!......Cliff

[uneasyrider]

Look at that artical in Hot Rod about the original Ram Charger car. That's a perfect example of optumizing the charge velocity to the engines performance curve. It was primative but it worked. I love the tuned fuel filler hose runners on the manifold. Great idea and easy to cut to length. Flow rate is velocity times the area. Match the charge velocity to the rpm and cid and the cyl. will fill faster and "pack" in more air and fuel. It's not so much the area but the velocity for two reasons. One, the time it takes to move the air/fuel mix into the cyl. to fill it at the given rpm and two, the pressure drop to keep the fuel suspended in the stream. If the velocity is too low the fuel falls out (condenses) into the runner and if the velocity is to low the cyl. isn't filled properly.

[Larry Navarro]

the above description raises a thought at the design of the WARRIOR intake in comparison to the Victor. If anyone has seen or used one of these intakes, the runner design resembles a "venturi"; starts out wide at the carb base and progressively funnels down to the head ports.
Perhaps the warrior design is to maximize the velocity of the intake charge.

[Skip Fix]

"As far as expensive, it's really not. His combo has been tuned through the years by trial and error" Yes very well tuned down to every detail, and awesome car in every aspect down to the paint and interior. The goal was to go fast with as many factory parts as possible in a low rpm "street" range and it does specatcularly.

I'll disagree on the expensive part-look at the total cost and TIME in swapping all the parts on a car or massaging them. Just paying yourself for the time much less the many parts, gaskets for making swaps is expensive. Track entry fees for test and tunes. I think at one time I heard there were well over 2500 passes on the car. Figure $20 a time entry at the track plus gas getting there. Yes the intake,heads may initially be cheaper but just add up freshening with good internal parts(valves,springs,guides), porting, etc, etc.

"Folks, running this quick just doesn't fall in your lap when you install a big high torque engine. It's about the combination of parts, the engine is simply part of a well thought out plan. Sometimes, as it did with us, it may take several years to figure out all the fine details to get everything working together for really quick runs......and did I mention parts breakage? To date we have broken EVERYTHING behind the engine, at least once!......Cliff"

Cliff has said it well, it's about the whole package. Cliff's car also recently went faster in the same rpm range with "bigger heads" (KRE vs 6X) so it's NOT JUST THE HEAD CC!!!(that dead horse Larry). If it were that simple Cliff's car would have lost bottom end and gone slower. If it was that easy where are all the 11 teen 3700lb cars in the staging lanes running cast iron intakes, Qjets and D port heads? Maybe a couple out there at the events that also get it done with all the right combination, but alot more in the 12s and 13s.

"If the velocity is too low the fuel falls out (condenses) into the runner and if the velocity is to low the cyl. isn't filled properly." If the velocity is too high the fuel also falls out and washes areas, what the wet flow bench "sees".

[uneasyrider]

Originally Posted by Larry Navarro

the above description raises a thought at the design of the WARRIOR intake in comparison to the Victor. If anyone has seen or used one of these intakes, the runner design resembles a "venturi"; starts out wide at the carb base and progressively funnels down to the head ports.
Perhaps the warrior design is to maximize the velocity of the intake charge.

More than likely plus give a good plenum volume to draw from. Of course it's all about what range you want the engine to run in. On the street it's always about compromise and on the strip you can gear it specifically to run at the intended rpm range through the quarter. You can put a 800hp 283cid in a Impala wagon you just better have a 13 speed Road Ranger tranny behind it to keep it on the top of the curve. (Just being silly folks so lets not go off about a 800hp 283, ok?)

[Larry Navarro]

Originally Posted by Skip Fix

...."The goal was to go fast with as many factory parts as possible in a low rpm "street" range and it does specatcularly."(Cliff R.)

I'll disagree on the expensive part-look at the total cost and TIME in swapping all the parts on a car or massaging them. Just paying yourself for the time much less the many parts, gaskets for making swaps is expensive. Track entry fees for test and tunes. I think at one time I heard there were well over 2500 passes on the car. Figure $20 a time entry at the track plus gas getting there. Yes the intake,heads may initially be cheaper but just add up freshening with good internal parts(valves,springs,guides), porting, etc, etc.

Oh c'mon Skip, kind of contradictory don't you think?
Better think about the $$$$ you have tied up in what...3 or 4 engines, multitude of parts, etc., just to break into the 10's and thats just barely......what a 10.99?
Oh yes, and the T I M E spent with those parts trying to achieve that elusive number. That's alot more than the majority of us here would ever have time or money to do.
Let's dismiss this TIME and parts swapping issue, as it's all part of doing what we enjoy, right?
Just be content and don't spend all that money trying to chase "that car" down the track.

[Tom Hand]

Larry,
It is interesting you brought this up as I think both the new Hot Rodding and Hot Rod had articles this month about small port, high velocity heads. Additionally, I just read it in one of the Circle Track books about how much sense it makes to use smaller ports that flow enough air and avoid the large ones that skew the power band up at the expense of providing power where you really use it. Something about “being able to make a street-able car way more powerful and more driveable and tame” by using small ports to keep the power higher in the lower rpm band????

Here is another really great quote and I’ll stop it at this.

"If you have a motor with small ports that flow enough air but then increase port size, you'll pick up some horsepower on top but give up a lot down low".

Seems I have heard this somewhere before!!

Tom

[Motor Daddy]

"Contrary to popular belief, flywheels DO NOT touch the ground"

I've heard this before also.