NVRENUF

Hi, currently in the process of getting info on a new engine combo.Going to go with a 383,406 or 420ci...not sure yet.Currently with the stock 5.7 bottom end,i was running 8 psi, then blew the #7 top ring land out a few months ago.With the new engine,it will obviously be substantially stronger so the boost will probably go to 16 lbs...again,not entirely sure yet.Just wondering what's good or bad in the after market cylinder heads? I was looking at the Trickflow's & heard good things about them.AFR's are suppose to be good to.Just curious as to what guys are using & whats the best.

Thanks in advance for any input!

z28freak84

depends on how big you go on the motor... but AFR all the way.. get the 210 for a 383-406 deal. and a 227 for the 420. And use the 235 if you step up to a 434ci.

fast82z

iTrader: (1)

I'm using a set of trick flows, and there's nothing wrong with them, but better power/times could be had with better heads like said above me. Also, from a D-1SC, you may only be able to get 15-17psi out of it specially with bigger motors. When I had mine it was about max effort and made 15psi on my 383.

Orr89RocZ

iTrader: (20)

But it also ran 9's so how much faster do you want to go ? lol

Any of the AFR stuff is good, trickflow is also good. Others like brodix/dart are good too. Lots of choices

NVRENUF

Thanks...I will also see what the engine builder recommends.I've heard good things about both Trickflow & AFR, so it's probably pretty much a toss up.
Does anybody get port work done to them after or just run them as they are straight out of the box?

Also looking for any advice on the engine combo/components.I have a thread posted in the General engine tech forum as well (more info on the car is there)

Thanks

Orr89RocZ

iTrader: (20)

AFR's seem to be the best out the box. Only thing I did was replace the rocker studs with ARP 7/16 stuff and shimmed the springs for more pressure for my cam.

Other heads that are not CNC'd may have rougher ports and could use alittle sanding/grinding to smooth things out. I got to check out several heads down at Summit racing and I wasnt impressed with alot of them, most were cast. AFR ports seem to flow the best out the box compared to all the others. They may be a hundred or 2 hundred bucks more but I think its worth it.

fast82z

iTrader: (1)

Yes I did go 9's with the D-1SC and trick flow heads, but I'm also using more cam than others usually do and that at least partially makes up for the flow my heads don't have. With better heads, a smaller cam can be used for the same power and better manners. And as far as how fast I want to go, I'd like to see an 8.5, but things will probably really start hitting a wall around 9.0 as far as durability.

NVRENUF

Looking on both of there websites, it says Trickflow only has the combustion chambers CNC machined while AFR CNC's the chambers & both runners...which obviously sounds better.The AFR's seem a little pricey though.I'm assuming the prices they had were per head? The prices were $1500 - $2000...unless they mean per pair? The Trickflows I priced out a couple months ago were approx $1600 for a pair.Again,also going to depend on the cost of the rest of the engine.That money issue may lower the HP numbers a bit...Lol (and the exchange rate!)

Thanks for your input!

fast82z

iTrader: (1)

AFR heads are also priced for the pair. Summit pricing of roughly $1500-$2000 for a pair of AFR's. In all reality, someone would charge in the neighborhood of $400-$600 to port a set of heads. Having CNC runners is worth basically that. If you were to buy a set of trick flows and have them ported, you then have a set of $2100 trick flows that may or may not have been ported well depending on the person that did it.

NVRENUF

Had a little more conversation with the engine builders, owner is away right now so still waiting on the prices.Could be looking at a 427 ci small block.Looks like AFR's are the way to go for heads.Priced out the 195,210 & 227's, they were $1614 & $1730 for the pair...and going on sale next week, so even cheaper then! Just need to nail down the engine size & cam more.
He was saying mt Superam is not the greatest due to the angle of the air entry where the lower runner meets the lower intake.He said to look at it & see if maybe I can port the hell out of it to straighten out some what.The intake is staying for now, maybe down the road find something better but for now,the Superam is staying....the engine's going to cost enough as it is!
Anybody run an intake set up that works better with a Procharger & approx 15 psi boost? and leave the throttle body in the relatively stock location?

Thanks

Kingtal0n

looking for a recommendation or an explanation?

explanation is what I do:
the larger you go with port sizes the slower the intake port velocity will be thus you will have less "movement" (swirl, mix, atomization, call it what you want) and therefore you will have more of a fuel puddle/larger droplet size/harder to fuel efficiently situation (compared to smaller ports)

The beauty here is that modern EFI fixes most of this. You can run tight corners for the airflow (look at modern intake manifolds) without worrying about the fuel falling out of suspension (as with a carb).

So end of the day a larger port is not as bad as it would be, but it still has negatives:
Since the air is moving slower there is less of a peak VE at any situation in which you are not flowing to the ports potential. So for instance during part throttle stoplight escape, the air will be more sluggish (and have less of a tendancy to flow into the cylinder during piston up movement) and your overall peak VE's will be lower... basically less torque because of smaller combustion, and if the camshaft is also "overlap / high duration" The effect is more pronounced to the point where you can actually waste fuel cruising or part throttle situations.

if cruise / fuel economy / daily driver / efficiency is a NON issue then you do NOT need to worry about ANYTHING except the maximum flow potential of the head you will use. If you have a 427 cubic inch engine the math says:
427 X max RPM (lets say 6000) X 3456 = CFM
or*
741 CFM @ 100% VE

The trick here is 100% VE @ 6000 RPM. That comes from a good head, cam, and intake combo.
So lets say your head flows only 600CFM with a XX" natural H2O pressure drop. To hit that 7XXCFM number, you are going to have a lower than atmospheric pressure ratio (basically a vacuum instead of atmospheric pressure) and that is going to extract performance (because you are working against the vacuum, exactly the same effect as using a restrictive air filter- reduction is performance) This is why a larger port will "make more power" technically you arn't making more power you are just allowing more air to flow unrestricted which MEANS more power ONLY and ONLY IF: The engine can actually use the flow.

So if your cam is restrictive at 6000RPM (say 212*duration intake) obviously the intake valve is not going to be open nearly long enough to take advantage of the displacement at that RPM... So it doesnt matter HOW Much your head flows... the flow will stop when the valve slams shut and thats all your going to get.

So each part must be taken accordingly to the combination at hand:
if you intend to hit 100% VE at or near 6000 RPM then your camshaft has to have the duration for that RPM, your head needs to flow nearly the required CFM at that rpm, and the intake manifold must not posses a property that will subtract or negate from your cam/head combo (such as long intake runners that will cause acoustic pressure waves that will disturb the natural tendancy of air to flow into the open intake valve even after the piston has reversed direction)

Now to the turbocharger or supercharger: It doesnt matter. focus on building the engine to achieve a high VE naturally aspirated (if all out performance is the goal like i said not fuel economy / daily driver) then the added boost will be WHATEVER IT IS and that will compound onto what you have built the engine for- there is no "turbocharger" Designation for all out performance.
If ECONOMY AND PERFORMANCE is the goal, THEN you start to factor in the boost for your part throttle situations and economy purposes. THEN you do the math to see how small of a port you can get away with how long of an intake runner and how small of a camshaft, you make VE% sacrifices up top (high RPM) for the gain in low rpm VE's that will be the heart and soul of your economy / daily driver and you DEPEND upon the forced induction to make up for the lack in your VE goal up top.

did i say it right

TexasLT1

I'd sure like to see a 600 CFM head

Kingtal0n

The numbers are flat, they are generic based on what the ENGINE flows all together. When I say if your head only flows 600cfm I am referring of course to the total flow capacity of every port in every head (if your engine has 2x heads or 4x heads or whatever)

I am used to working on engines with single head, twin cam design. Therefore, its just one head and 4-6 ports that collectively flow enough to support 100% VE at 8000RPM (less displacement obviously) at whatever CFM that is. The manufacturers design the heads with the smallest ports possible to maintain that crisp response, yet they can not be too small because the manufacturer knows the engine will probably become modified. In the case of a typical pre-lt chevy they assume you will change the heads for big performance. In the case of high performance OEM 4/6 cylinder applications... the manufacturer knows that there is no aftermarket head option, so for performance purposes the head must be capable of supporting whatever power goal is conceivable without replacing it...

Orr89RocZ

iTrader: (20)

Regardless, if he throws a nice cam, AFR 210's, and a decent intake setup on a 427, its gonna make some power with a D1 at 10-15psi. IF the D1 is maxed and only makes 10psi on that motor, its still going to be near 580-600whp and run close to 9's. I went 10.3 at 135 on 10 psi with no launch.

Kingtal0n

427 @ 10-15Psi is similar to a 700~ cubic inch engine in regards to breathing capability. Yeah, thats about 600whp considering rotating loss and drivetrain loss and efficiency losses... Ultimately it depends on the RPM and VE since thats your torque and RPM thats going to be your horsepower number.

If he spins to 6k with an N/A 427 it should require:
427X6000/3456 * .069 (using turbo constant anyways) = 51lbs/min (500~horsepower) @ 100% VE

if he spins to 7k with an N/A 427 it should require:
427X6000/3456 * .069 = 60lb/min (600 horsepower) @ 100% VE

Lets say he keeps it around 6k RPM, now lets add boost:
427X6000/3456 = 741CFM @ 100% VE, Now add 10PSI of boost @ 75% efficiency (proper size turbo): 10 * .75 = 7.5 perfect psi (ideal)
7.5Psi is 51% of 1 atmosphere so

741 * 1.51 = 1100CFM * .069 = 77lb/min
Around 750Horsepower BRAKE
or
750 * .85 = 650 Horsepower to the wheels (15% drivetrain loss)

This assuming his head/cam/intake supports 100% VE @ 6000 Rpm.

And I cant talk about 1/4 mile times because that is dependent on factors besides just the engine math. My area of interest lies within the engine itself, the free radical chain reaction you call combustion... the thing that makes it possible to go fast using gasoline and oxygen that we breath in the same manner as the human body does (that is oxidation / metabolism to produce energy)
this is my area of study

Orr89RocZ

iTrader: (20)

I have a couple of turbo math equations that can be used to get a pretty good idea what your motor will make on x amount of boost. using those figures, for a 6000 rpm 427 assuming 100% VE, 120 degree intake temps, BSFC of .60, this motor will make 775 crank hp at 10 psi. Based on my motor results, I'd estimate this combo above to make that or more, and probably more since my motor only peaked at 5300 but i have some issues with it and its probably going to peak higher when i sort things out... but still the fact remains this motor with 26 more cubes and 500 or so more rpm abililty will make a good 50-75 hp more I bet..maybe 100 more. 850 on 10 psi would be insane to see, but I dont know how much air the D1 is capable of flowing.

Kingtal0n

you are one day late

TexasLT1

*edited*

dennisbernal91z

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subscribe

articwhiteZ

iTrader: (56)

just about the same thing