cast iron intake vs aluminum high rise dyno test( round 2)
 

So i get a customer in seeking more power (long story short)
Lately since there has been threads in here that cast iron intake manifolds perform better than aluminum intakes in mild combos
Here is a appple to apple dyno test.

as arrived cast iron intake
http://img13.imageshack.us/img13/4543/xvvx.jpg

http://img543.imageshack.us/img543/5325/ls0d2.jpg

http://img853.imageshack.us/img853/3316/9eem.jpg

http://img35.imageshack.us/img35/918/x42z.jpg

19 RWHP GAIN @3700RPM

http://img560.imageshack.us/img560/5452/kgxk.jpg
22 RW TQ @2500 RPM


Sharing my testing here, if i get any smart a__ reply's back regarding the integrity of my dyno testing i am shutting this thread.

Harry, what's the aluminum manifold? Crosswind?

yes Rocky, its a copy cat of Crosswind.

Any other adjustments made to the tuning of the car? Is that a carb adapter on the iron intake? I'd be curious to see back to back runs with a spread bore carb.

I must be stupid, as I've been told, but which result is which?

The TQ curve shows an improved inhale across a broad RPM.

Personally, i'd like to see what a Q-JET does. ( should be same, right?)

Harry, I know you can't spend all day doing this but I notice that sometimes you get better numbers on the second pull just because(maybe because all the cr@p gets blown out on the first pull). I also wonder what a regular performer would do against the high rise? I ask because I'm thinking about going back to the regular Performer instead of the RPM but I don't want to if I'll be giving up that much.

the stock intake pull seen here was at its opimal tune,
the black thingee under the carb is 3/8 spread bore spacer with 4150 sealing gasket was used under the square bore Edelbrock carb as it arrived to me.

the red graph is iron intake and blue is aluminum intake.

noticible difference in power.

"Personally, i'd like to see what a Q-JET does."
would fry's go with that shake:D
its not equiped with Q-jet and i am not spending my dime on this one.

true if car is carboned up,unloading it wot on dyno you blow the carbon nicely away and the second pull will be miniscule higher.

"I also wonder what a regular performer would do against the high rise? I ask because I'm thinking about going back to the regular Performer instead of the RPM but I don't want to if I'll be giving up that much."
grab your performer intake & comon by and well do exactly what you want.

That looks great for street use. A lot of the other results extend the test out ot 600o rpm, and it does look like the lines begin to converge at higher rpms, and maybe the lines cross at some point, but for daily driving the extra torque from 2000-5000 rpms is enough to notice, at least on that cam/head combo. I know the edelbrock used to claim just about the difference your test shows between their aluminum and stock manifolds.

Based on the 350 max torque numbers, I assume this is close to a stock motor, with close to stock cam specs.

Harry, can you share combo details?

The results are pretty close to what we found using a square bore carb on a factory spread bore intake (unmodified) with an adapter/spacer. The spacer/adapter is a significant miss-match between the two parts. The last time I tested a deal like that it cost us just under 30hp on a pretty stout 455 making just over 500hp.

We did some dyno testing a few years ago with a pretty stout 428 engine and after finding the best tune for the carb and distributor, we swapped out 3 intakes back to back.

The first intake tested was a re-pop HO intake, then an Edelbrock RPM, then my own iron intake. All three intakes were gasket matched exactly to a stock Felpro blue gasket, and the HO and iron intakes were opened up under the carb to the same size/shape as the RPM. The runners on all three intakes were unported/as cast.

The HO intake made 487HP, the RPM made 491HP, the iron intake made 497HP. No spacers of any kind were used during the testing.....Cliff

While I don't doubt the aluminum intake has the ability to make more power, I can't help but wonder if the square bore carb adapted onto the spread bore iron intake may have hurt it's power to some extent?

As much as i know i will:
its a 400ci maybe 30over rebuild by local engine builder machine shop,no relation to me
it has 670 casting heads and 175psi cyl pressure i checked and its doing fine on our Ca. piss 91 octane, i dont know whats the pistons used in it (meaning SCR where it is) cam wise again i dont have details but it has 16to17" vacuum at idle and its 4spd manual car
the best part get this, its in a 1964 Chevrolet Impalla SS.

Irelevent mismatch or not, the test was here again apple to apple
1 more time remove cast iron intake & install aluminum intake with no other changes

The results are pretty close to what we found using a square bore carb on a factory spread bore intake (unmodified) with an adapter/spacer. The spacer/adapter is a significant miss-match between the two parts. The last time I tested a deal like that it cost us just under 30hp on a pretty stout 455 making just over 500hp.

I have seen the same Loss of power as Cliff did. On a Boss 351 engine and a Boss 302
with a Shelby 8V manifold when I installed open spacers on four hole manifolds.

Ken Maisano

Why should the results be surprising?

The charge has a much straighter shot with that aluminum high-rise. And the iron intake is going to have a lot of primary reversion with anything other than a q-jet.

great post thanks for sharing. also, even if the plots were a perfect overlay the aluminum is much lighter and that in itself is a performance gain. just wondering why you mark the horsepower points where you did and not at the peak position. again thanks for sharing.

Jim

Apple to apple would be using a carb that bolt up on both intakes w/o any adapter of any sort.

Today everybody knows an adapter between a squarebore carb and a spreadbore intake kills power.

Glad you said it Kenth, as I hate to be the one to point out that NOTHING about that test was "apple to apple".

Installing a square bore carb on a factory spread bore intake with an ADAPTER doesn't correct the HUGE miss-match between the two components. The miss-match causes the air to have to make several "bends" to enter the plenum areas, which will kill power.

To be perfectly honest, I'm surprised the numbers are as close as they are......FWIW......Cliff

Thanks for sharing the results - the customer must have been happy, that's a noticeable change!

In defense of Harry, the customer is using that carb along with the necessary adapter to run it on that intake.

So he would gain HP by the aluminum intake.

He didn't do a test for optimum combos for each?

If all I had was this carb, what would make me the most power?

My 2 cents.

:)

I still think the test is interesting and thanks Harry for posting it.

If you open the plenum up on the iron intake to match the carb, I bet a 10+HP gain.

As far as adapters-track swap-Brad Urban Carb Shop modified 800cfm 73 SD SR Q jet on an HO intake ported E heads 259@ 0.050 solid roller.Swapped on a Demon(yea one of those crappy things) 850 DP WITH spread bore adapter-idled great out of the box and picked up 0.25 seconds and 3-4 mph.

So if it hurt flow(and yes I matched it and cleaned it up) I guess it would have gone faster!

That said swapping the same Demon on a Torker II on this motor really picked it up and smoothed out the idle even more.

Thanks for sharing.
This proves that in this case, one combo as installed made more power than the other as it was installed on this car at this time. If somebody is interested in making exactly the same swap....you can possibly expect this result.

Thanks for sharing Harry. We need more unbiased test results published here. This confirms testing I did decades ago at the dragstrip. The stock UNMODIFIED manifold was not ever the best choice.

Most the SS racers using Q jets use an adapter be they Chevy or Pontiacs.

I'm just not seeing than many bends using this,more a funnel or reverse funnel depending which direction it goes.

http://www.tdperformance.com/site/?d...art=10&limit=5

Now this Edelbrock adapter might transition it a little smoother.

http://www.edelbrock.com/automotive_..._spacers.shtml

Maybe like how the 75-78 D secondary EGR intakes flow so bad-might not be that significant.

I guess that explains the chevy orange paint. With just loosing the adapter it seems to be some of the differance between the 2 no?

"Most the SS racers using Q jets use an adapter be they Chevy or Pontiacs."

Skip, last time I looked ALL of them were using adapters of some sort, and NONE of them had stock intakes under them.....Cliff

Thanks for the testing, Harry, and Merry Christmas and Happy New Year!

Tom Vaught

Thanks for the testing info.

Anyone know the height difference between the intakes?

Presumbing the Crosswind is the same or similar height to the Performer RPM intake ?
If so Edelbrock suggests their RPM intake is about 1-1/4" taller than a "stock" intake.



.

Cliff my point was the SS guys are making lots of HP and using an adapter so yes they might not be perfect flow but might not be as bad as we think in flow or mixture distribution. And early Rochester on a SBC and a Victor really looks weird! I remember back when there were lots of 2 BBL classes seeing them on an aftermarket intake looked off too.

Maybe someone with an RPM intake(Crosswind)use a square bore carb with an adapter(since intake has a plenum shaped for both), then the same carb with the same thickness square bore spacer if we want to really see what just the adapter does.

By the graph, doesn't look like the original set up was optimum to begin with.

Jim & most here
I have lots of other tests similar to this intake test & so many different components(carbs-headers-power spacers, camshafts, ignition boxes msc etc etc) dyno testing performed in my shop and i don't post results here on daily basis due to some critiques coments that i have to rebuttal back at,in anycase anyone is curious about specific item what they would like to know and happens that i have dyno test results,they can always pm me direct and i can give them unbiased direct results,it doesnt matter for me what the concerend persons intent afterwards is & what they want to do cause i am not selling them products nor services as some do here,
but anyways to answer why i marked the cursor in the graph where i marked it is:
in street cars peak hp don't mean didly, you have to look at "area under the curve what it makes oppose to peak numbers". hope you understand what i am saying.




indeed it is ,and i didnt have to say to the customer. wait oh no you have iron intake and spacer (not adaptor), i have to buy you a Q-jet first and install it and if it makes more power you're happy, if it doesnt now oh lets remove it and start all over;)


John i like the termenology you have elected to use"In defense of Harry"
cool thing there as you can see somes rebuttal at this as i said above!
i like what youre saying here
"If all I had was this carb, what would make me the most power?"
the results are posted there buddy thanks for making it clear to some.

David & Bruce Thanks for understanding cause we're on the same page.


Mr boost engineer same to you, you mean don't have few cents to throw at this.

as i said in my post#8 the black thingee is spacer not an adapter
lets get the controversial smoke blowers to agree that this is not ADAPTER
http://img22.imageshack.us/img22/5558/acdd.jpg
this is a 3/8"tall spacer that was mounted between the edelbrock carb and iron intake , and also FYI Edelbrock carbs baseplate have dual bolt holes as i am taking extra time to post pic here to demonstrate that there is no ADAPTER used, spacer only with cast iron intake and sealing plate with aluminum intake!
http://img189.imageshack.us/img189/9600/seg9.jpg

Adapter or spacer is a play on words, it plays the same role here. Anyone with half a lick of common sense can see that there is still a terrible miss-match between the bottom of the square flange Edelbrock carburetor and the top of the 4 hole stock intake.

This is NOT present when the same carb is used on an aftermarket dual plane intake, so it will ALWAYS make more power.

I'll post some pics later to show how horrible the miss-match really is between the carb and the intake, and that the "spacer/adapter used only raises the carb up slightly to provide a slightly better shot at the holes in the stock intake.

"Cliff my point was the SS guys are making lots of HP and using an adapter so yes they might not be perfect flow but might not be as bad as we think in flow or mixture distribution."

Skip, completely DIFFERENT deal than what is going on here. They just use an adapter to get the carb bolted to an intake under it that has a FULLY OPEN plenum. There is no "miss-match", or anything close to it. The Super Stockers spend countless hours playing with those "adapters" and find pretty big gains with them. I have witnessed HUGE gains in power between two different ones on back to back dyno pulls, so there is something to gain by playing with those things.......FWIW.....Cliff

Cliff agreed there is a mismatch, but there was also one on my car using the same intake(no plenum divider massaging) different carbs with adapter and it still picked up the car significantly-so the mismatch might not make a big deal is all I'm saying. There is also soem mismatch using an open spacer even with a Qjet as some of the primary flow can use that 1" to try and turn into the secondary hole yet hits the flat factory area between the bores.

And that Q jet had slightly bigger primaries so if we say my motor needed that extra 50 cfm the Demon provided might not be that 50 cfm amount more. And the Qjet had dynoed equal to 850 Holleys on several motors-even a 500 hp Buick.

Harry,

Thanks for posting your results as this is indeed an apples to apples test if there ever was one. It doesn't get any simpler than that.

Keep posting results if and when you have the time because it is appreciated.

Paul

Fixed it for you :D
Thanks for taking the time to post.

That crossover on the 67 intake has seen some serious temperatures. Is the exhaust flapper stuck in the closed position??

http://imagizer.imageshack.us/v2/150.../543/ls0d2.jpg

Aluminum intake doesn't have a crossover.
Apples to... coconuts.

good observations; Was this all said with your Avatar ?

We all appreciate you sharing your testing as always we welcome sharing of actual dyno testing and drag strip testing but I don't believe this is an apple to apple comparison at all. The square bore carb on a Q-Jet manifold is a big mis-match. How about repeating the test using a Cliff prepped Q-Jet on the factory manifold and then put the Q-Jet on the square bore manifold with an adapter and see how that works. That would be another apple to coconut test but never the less it would be interesting to see those results.

Tim, I started my own thread on the topic....and...if you need any testing of the sort mentioned, I've done a LOT of them, dyno, and at the track, with every intake manifold and type of carb I could fit under the hood. We have a lot of test results with Victor/Dominators, and comparisons to T-II/HP 950's, and the Tomahawk intake with Q-jets and large CFM Holley type carburetors, in addition to scores of comparisons between q-jets, Holley's, Demons, etc on all sorts of intakes, with all types of spacers as well.

This happens since I do build a LOT more engines than I mention on the Boards, and we dyno just about every single one of them. Since much of the testing gives us results that don't sit well with certain "crowds", I put very little of it up here, simply to avoid a bunch of criticism and arguing back and forth, etc, etc.

I even did some of the track testing on another well prepared Pontiac powered vehicle, after taking some criticism right on this Forum that the testing I did was "flawed" being only specific to my own car (which is a bunch of horse crap right to start with)........Cliff

there is no exhaust flapper in this installation, with your wise observation to smear my thread,has it done to you that the black paint burnt off ? anyways most of your comments belong in the Clubhouse.


Tim I dont scratch my right ear with my left arm wraped around my head,if you have that kinda suggestion have your friend do that kinda test on his own time(since he's a legend on his own mind) and come back prove the negative results as i did with mine and i have a very happy customer with least amount of time and expense involved.

very simple test on how to gain some street horsepower, no need to get into apples to apples thingy here...I am pretty sure q-jet will have fare better on that stock iron intake.
many guys do this kind of adaptations and I am pretty sure they are clueless of the HP losses...Good post Mr. Harry.....

Here is something to think about. The stock steel intake weighs 42lbs while the performer RPM weighs 15. You would need to make 27 more hp out of the steel manifold just to compensate for the extra weight.

Well through all the back and forth on this subject it's a bit confusing for me so I'll ask a more specific question.
If I wanted to install a Holley DP on a performer intake, what type of spacer or adapter should work best? Or should one or the other be used at all?

At any rate I am glad for the posted result of the original test. Every little bit of information helps.