Stage 2 heads

[rag231]

Have there been any tests on ported vs unported, cast iron vs aluminum? I pretty much have my choice of what I want to strap on my next shortblock. I figured that the unported set wouldn't be all that bad, due to the smaller runners and overall port volume. All info will be greatly appreciated, this is a only an 800hp motor to be driven on the street 90% and track 10% now, so he says. Thanks

 

[turbobitt]

In my opinion it takes the same amount of work to use ported or non ported heads so just use the best of what you can get your hands on.
AG.

 

[norbs]

No matter what you do power will be flat under 4500-5000.............less than a stock TR, as mine shows that based on fuel use.

 

[rag231]

Norbs, do you think that the flatness is a result of the cam ( lift, duration etc...) and or converter that we are using or the volume of air that we are flowing? I wonder if the flatness can be engineered out. I believe it is in the cam. i had a buddy who went to a racers auction an got about 40+ cams from dirt track and Nascar teams. He only payed about $250 for the whole box. Believe it or not the most responsive cam to me came out of a Legends car. NA 270 stage 2 headed motor pulled very hard from a dig. I could be wrong but it always seemed that the larger stroke motors didnt have to pull as many rpms for the power to come in. That's me comparing my old 274 stage 2 to my current 256 stage 2. My buddy that has the 218 motor in the Indy light car can hit 10000rpm. If i get a chance, I will ask to see a dyno sheet if he has ever logged the rpm and horsepower curve.

 

[750H.P.V6]

I think some of the bad press Stage II heads get is due to the fact that by the time guy's get the idea to run them they are looking at a max effort combo. I also think there is the mis-conception that you have to run a giant cam and a lot of RPM to make them work. This is compounded by running a huge turbo and in a lot of cases low static compression all of which make for a lazy combo.

Neal

 

[norbs]

Well cubic inch will shift the rpm point down, but the fact is the port velocity is low and the port CC's are too big for high torque at low speeds. If you have enough converter you can help overcome this but it becomes marginally streetable. If you have access of dyno charts please post them,,,I bet none are too impressive at 4500 rpm..

 

[rag231]

Yeah I agree Neal, I want to engineer the laziness out somehow. Norbs what if the motor was 10:1 or 10.5:1, I know that I would have to lower my boost and run a little alky, but I would be able to take out that laziness on the street. When it comes to racing it, I would be at a loss. I havent even thought of Timing either.

 

[norbs]

Your fighting huge port volume and velocity vs CID still being too small. The compression may do marginal improvements, but as you increase the compression the less power you will make underboost, and reliability will suffer . The optimal number is about 9~9.5 to 1.

 

[Reggie West]

Well cubic inch will shift the rpm point down, but the fact is the port velocity is low and the port CC's are too big for high torque at low speeds. If you have enough converter you can help overcome this but it becomes marginally streetable. If you have access of dyno charts please post them,,,I bet none are too impressive at 4500 rpm..

There a few ways to make Stage heads work. IMO.

Spec out a cam that does not have peak torque at 5000 rpms. 224/224 will work well.

Use a turbo that does not require 6000 rpms to stall. a 66 or 70 with the correct turbine and exhaust housing will make all the difference. Compressor housing will help. Dual or triple ball bearing center sections will certainly help.

Spec a torque converter that stalls at 3400 rpm instead of 6000 and it will work just fine.

Lastly TUNE it.

It's been done. Ask Mac in SD, he will tell you all about it........

 

[Mike Licht]

What Reggie Said ^

 

[norbs]

"Spec a torque converter that stalls at 3400 rpm instead of 6000 and it will work just fine."

Is this refering to anyone I know?

 

[forcefed3.8's]

I drove Terry Houston's Stage 2 headed street car. It was a 4.1, 3.4 stroke, 8:1 compression, stage 2 heads, 76 Q-trim .85 3 bolt (old 11 blade Q), TH400 with a Precision converter probably a 0 pump, 218/218 solid roller. It had as much bottom end if not more than my old 245" 109. It spooled the 76 way faster and started making boost lower rpm. Now at 26psi, it went 10.20@136, where my old 109 went 9.86@138 on 23psi. At the time we both had 76GTQ turbos and I was running a 0 pump Vigilante 5disc in a 2004r.

 

[rag231]

That's the kind of info that I am looking for.

 

[norbs]

Based on your info it looks like the benefits of the flow the large ports are being choked by the 3 bolt tiny exhaust side, a real mismatch for the S2 heads...exh flow is everything...

 

[Reggie West]

"Spec a torque converter that stalls at 3400 rpm instead of 6000 and it will work just fine."

Is this refering to anyone I know?

No Norbs that was not meant for you.

 

[turbobitt]

No Norbs that was not meant for you.

I would be happy with a 3400 RPM converter.... All I can get out of my heap is 3000....
AG.

 

[Mike E]

Based on your info it looks like the benefits of the flow the large ports are being choked by the 3 bolt tiny exhaust side, a real mismatch for the S2 heads...exh flow is everything...

You understand that if you think exhaust flow is everything, the below is your result.

No matter what you do power will be flat under 4500-5000.............less than a stock TR, as mine shows that based on fuel use.

For me useable power and ET are everything and exhaust flow is what it is to get there. Sure I'm giving up a few top end hp, but the trade off is worth it. My 277 breathing through a 3 bolt .85 a/r housing does quite well. I'll send you a datalog from a crap tune to show you. 9lbs. at 3200 rpm and goes to 28-29 in about .5 seconds if I remember right.

You like numbers. My car ran 118mph @3470 lbs. in the 1/8th. What kind of fwhp does that calculate to? I'm running a 6768 turbo rated at 935 hp.

 

[Reggie West]

I would be happy with a 3400 RPM converter.... All I can get out of my heap is 3000....
AG.

Ok you took the bait so here is my suggestion. And we have discussed this before too.

I dont think the displacement is a major hinderance to your combo. I do think you have a massive turbo with 1.14 AR hot side that is a major hinderance.Your heads are not a problem either. Yes they are bigger ports than stock or aftermarket heads but you can run the same amount of air through those at a lower boost level ( yes less resistance to flow).

I would recommend in my HUMBLE OPINION, a 67/68 dual ball bearing turbo ( Comp Turbo shameless plug but they work) with a .85 housing on it. You can run a 4 bolt exhaust housing on it and there is no downside to that either. It will spool very fast

The cam you are using is bigger but all they do is keep moving peak torque higher in the rpm range with higher duration numbers. I have tried 12 different cams in street motors and Stage motors and dynoed all of them. I have seen the numbers.

If you do this you can get the stall speed of the converter out of the upper troposphere and it will be a streetable combination that performs like you want.

With all of the electronics you have on that car you can make the motor sing a song like the F1 cars do. Point being you have everything else you need to make this a streetable car that makes power well before 6500 rpms.

I know then you would be happy with the car.

 

[turbobitt]

Ok you took the bait so here is my suggestion. And we have discussed this before too.

I dont think the displacement is a major hinderance to your combo. I do think you have a massive turbo with 1.14 AR hot side that is a major hinderance.Your heads are not a problem either. Yes they are bigger ports than stock or aftermarket heads but you can run the same amount of air through those at a lower boost level ( yes less resistance to flow).

I would recommend in my HUMBLE OPINION, a 67/68 dual ball bearing turbo ( Comp Turbo shameless plug but they work) with a .85 housing on it. You can run a 4 bolt exhaust housing on it and there is no downside to that either. It will spool very fast

The cam you are using is bigger but all they do is keep moving peak torque higher in the rpm range with higher duration numbers. I have tried 12 different cams in street motors and Stage motors and dynoed all of them. I have seen the numbers.

If you do this you can get the stall speed of the converter out of the upper troposphere and it will be a streetable combination that performs like you want.

With all of the electronics you have on that car you can make the motor sing a song like the F1 cars do. Point being you have everything else you need to make this a streetable car that makes power well before 6500 rpms.

I know then you would be happy with the car.

About the only think I just learned from your post is that you know more about my car than I do. And I'm apparently unhappy with my performance. I guess tripping the 60' beams with a 3650# car on the rear tires is not good enough for your over achievers.
Oh well.
Allan G.

 

[turbobitt]

If you do this you can get the stall speed of the converter out of the upper troposphere and it will be a streetable combination that performs like you want.

Oh, and please tell me more about what I want.
AG.