23 degree heads for twin turbo

Alright you guys, I need to be choosing my heads, as i know the AFR 190's I have now won't be too helpful trying to make 950 hp.
I have basically decided that I want 23 degree heads, to keep things as simple as possible.

I am destroking my 420 to a 406 and adding two turbos that will make 16 psi. I wont rev this engine above 6500rpms, and it will have a full roller valvetrain, and a solid roller cam. Specs will be tailored to cylinder heads.

Basically I will need a port larger than 220cc's. A bunch of you have been helping me out, and suggested some great heads. Thanks for doing so. Now I need to settle for one.

I like AFR's 227, Brodix's WP -10 SP X, and All Pro's AP220S & SP heads. I havent seen flow charts for All Pro's heads but I know the Brodix's flow more than the AFR's, but they also cost 4 grand. Does anyone know the price for All Pro's heads and the flow numbers?

My goal is 950 hp, any help is accepted. Thanks guys.

Hunter

what kind of intake do you plan to use? This will dicate your head choice since certain intakes wont go to a 1206 gasket which is what you are describing you want to use

my bad....

I will be using a custom sheetmetal intake, either from Hogan's or a local guy. Gasket choice will depend on heads, as I will be getting the intake made after i choose heads.

Hunter

What's your budget?

Originally posted by Mindgame
What's your budget?

ditto...

Im gonna let myself spend 3000 on heads. This including porting, valves(titanium), the heads themselves, bronze guides, and spring seats.

I can fudge a little and skip the titanium valves for now if need be.

For 2 grand the AFR 227's seem pretty good....but tell me what you guys think.

Hunter

DUDE check out pro action heads. www.procylinderheads.com... go through www.dynoflo.com and they can get you some awesome deals on those heads and other hardware. i PROMISE you, you will not be dissapointed. Also, on the note of porting, you might want to do a little home porting on the exhuast side, and its not that hard at all. just an idea, but definetly check out the pro action heads and CALL dyno flo to get the best deals. I'm also doing a twin turbo 388 stroker which i plan on porting some heads for.

Ya they got some good heads, I had their vortech replacments on my old 350, I loved them.

Their E/I ratio is kinda lacking, which is why the AFR's and Brodix heads are calling to me. But nothing some exhuast porting cant help. Ya and I plan on porting myself, but paying for flow bench time.

I think I will plan on the AFR 227's for now. They have great flow, good e/i ratio, and for 2 grand, I can use that money to port them some more and get the titanium intake valves I want. Nothing but Inconel for the exhuast.

How much boost are you planning on using and what turbos? I hope all goes well with your project.


Hunter

Do you have some flow #’s for your AFR 190’s?

You might want to do some math... I’m not sure where exactly you came up with the 950hp or 16psi numbers, but assuming that you choose your compressors well (and are at over 70% adiabatic efficiency at your HP peak), use a decent intercooler (again, I assumed that a decent intercooler would be about 70% efficient or better), and also assuming that the rest of your combination (especially the cam) strikes a good balance between the rpm you have to turn that the flow dynamics imposed by the turbos you should be able to make your power peak at about 7Krpm with about 260cfm flow on the intake ports… all of which really should be achievable with mildly worked 190’s. Personally, I’m a firm believer many builders that end up making their number end up going overboard with the port sizes on the heads they choose just to be safe at the expense of midrange, difficulty tuning…

For that matter, since you already have the 190’s I don’t really see the harm of putting it together and if you just can’t do it upgrading later…

I agree with Mark. You probably don't need heads that exotic to make 950hp in a forced induction application. Also, why "950hp"? Seems like a pretty arbitrary number.

Rich Krause

well, rember, the better you flow, the less boost you have to run and the less heat and risk of detonation, AND.... you can use pump gas without problems. Our goal is about 315/240 @ .6 and 750 hp @ 6-7 psi.

www.weldtech.com

get the CNC ported track 1 heads...head flow isn't everything

I would be extremely surprised to see an AFR 190 pull to 7k on a 4.125 bore small block with a blower. You'll be running out of port by 6500, probably sooner considering the extra mass your pushing through the port.

Ok, your choices seem fine. The AFR 227 is a good head as are the others. Another choice you might want to look at is the Dart Pro 1 227 (full CNC). It's numbers are stronger than the full comp. port AFR. Dart builds a good head... just wish they still made their raised port 23* heads.
I'd classify the heads in this way.... The Dart 227 CNC, AFR 227 (full comp. port by AFR) and the WT Track 1 recommended above. They're all on the same playing field, but my choice would be the Dart first.... it's about $500 less than the Weld Tech T-1. It'll get the job done no problemo. Just basing this on what I've seen from guys I race with.
The -10x is on another playing field, especially when you start talking about Weld Tech's HVH 10-x.... that head romps all of these throughout the lift curve but it's more money. Just over 3k.

So, I'd go with the Dart 227 Pro 1 CNC. You can buy a smaller port and work it to the size you need (CFM means nothing next to proper port shape and csa) or you can buy the head you need and go. My .02.

-Mindgame

I check the Dart heads, and they seem like an excellent choice. Do you know who sells them? I checked all over and couldn't find anyone who carried the 227 CNC's.

Hunter

Friend of mine got his from Herbert Performance:
http://www.herbertperformance.com/

Their website is down but you can get a catalog/information at that link.

-Mindgame

Thanks, I will try them.

Hunter

Originally posted by Mindgame
I would be extremely surprised to see an AFR 190 pull to 7k on a 4.125 bore small block with a blower. You'll be running out of port by 6500, probably sooner considering the extra mass your pushing through the port.

You’re right… I came up with that # assuming that we were talking about a 350 (didn’t really see any details on what he was actually building in the thread). If you make that a 383, it will only have to turn to about 6000 to make that same power and less if it’s a 396…

Density has little if any impact on how the cylinder fills, under boost it’s mostly about controlling relative pressures on either side of the valves.

Originally posted by menlatin
well, rember, the better you flow, the less boost you have to run and the less heat and risk of detonation, AND.... you can use pump gas without problems. Our goal is about 315/240 @ .6 and 750 hp @ 6-7 psi.

Only to a limit. In this example we’ve already got ports that flow over what you need to to fill the cylinders at the given RPM. More port flow just won’t get used and boost will stay the same, since the boost pressure you will see (the restriction to the airflow) is the available volume of the cylinder.

Originally posted by WS6 TA
Density has little if any impact on how the cylinder fills, under boost it’s mostly about controlling relative pressures on either side of the valves.

"Mass flow rate = Velocity x reference area x Rho

where Rho = density of the air"

John B Heywood on IC engines

So I guess it does play a part since it is a variable in that equation. If you crunch the rest of the formula you'll see that it plays a significant part in the outcome

Only to a limit. In this example we’ve already got ports that flow over what you need to to fill the cylinders at the given RPM. More port flow just won’t get used and boost will stay the same, since the boost pressure you will see (the restriction to the airflow) is the available volume of the cylinder.

You can't base cylinder filling on what you see (staticly) on a flowbench. It's a nice theory but once you've been around more than one or two race engines you'll see that it just doesn't work that way. Not in my experience over the last 20+ years anyway.
All of this doesn't account for frictional losses, pumping losses, etc.. Then..... how do you propose to know the pressure differentials?

-Mindgame

Originally posted by Mindgame
"Mass flow rate = Velocity x reference area x Rho

where Rho = density of the air"

John B Heywood on IC engines

So I guess it does play a part since it is a variable in that equation. If you crunch the rest of the formula you'll see that it plays a significant part in the outcome

EXACTLY

There is nothing there that says that the volume changes.

The way that the cylinder fills doesn’t change (well, not that much)

You end up with similar volume, similar velocity, but that volume and velocity is at a higher mass/density of air.

16psi with an adiabatic efficiency of 75% and an intercooler efficiency of 70% (both very reasonable #’s using a modern, well matched turbo and a decent intercooler) will amount to a density of 1.95 x that at 14.7psia. So basically he just needs enough airflow to make 950hp/1.95(density ratio)= about 487hp NA…

Mildly touched up 190’s will do that on well built engine. Hell, Joe Sherman used AFR 215’s on his engine master’s engine that made 604hp NA… and you’re telling him he needs 227’s?

If the engine isn’t that well built, his particular set of 190’s suck ass or his intercooler is assembled by a monkey using a rock and a stick then considering that the engine is turbocharged and it is SIMPLE to change the wastegate setting and a few # boost will make a much bigger difference in the total power produced then spending $1500-2000 or more on some 227’s (which won’t let the engine make any more power without installing a larger cam and/or using the turbo to force more air into the engine to extend the rpm range).

teamsleep,

Go here: http://www.airflowresearch.com/

then go to "articles" then "plan of attack".. you'll see a TT 383 setup running right at the level of power you're proposing. They're using the AFR 210 (complete CNC ported). Remember you are building a larger engine with greater airflow demands... draw your own conclusions from there.
Inconel exhaust valves.... also a good idea, so factor the cost in.

-Mindgame

I have to agree with Mindgame on this one. Density has a huge role in filling the cylinders, even more so on a turbo/super charged engine because when we compress all this air, it expands, and then we cool it down to increase its density and throw it into the engine.

The point of turbo/super charging your engine is to force more air into the cylinders than a N/A motor can, by pressurizing the intake charge. Its almost like adding displacment, though I am hesistant to say that because its really not true, but it makes it easier to understand.

Mindgame, I have that article, read it like 400 times, that got me started on the twin turbo engine idea, thanks for the reference though. The Dart 227's are looking like my choice for now, and when I get them, I will port them some more, trying to maximise flow for the given intake runner volume.

Thanks

Hunter

I remembered reading that article some time ago but could not for the life of me remember where I had seen it. Obviously I found it but that build is pretty much in line with what you're doing so in my opinion it's a pretty relevent comparison.

You might be surprised with the Pro1 CNC heads. I know I was.
I've seen quite a few CNC heads over the years... the CNC stuff from Weld Tech, Chapman, Dart are quite a bit better quality than the run of the mill CNC stuff you usually see. The surface finishes are much better, probably due to tighter toolpaths... takes more time but you get a better head. My 15* heads are CNC machined by Chuck Riddeck's outfit PRED and the surfaces (especially in the combustion chamber) are exceptionally smooth, same goes for a set of sb2.2 heads I had reworked by Don Losito after dropping a valve.
On the AFR stuff and the vast majority of production CNC heads, they could stand a bit of work. Most need a seat-to-throat blend and most "head guys" you take a set of these to will start right there. Other than that, the good heads will pretty much be ready to go out of the box. The Dart 227 CNC heads are pretty much on the same level "quality wise" as the heads I've seen from Don, Chapman, Weld and now PRED. So I'd think twice about rubbing on them too much. I'd check the seat blend and work that if it needs it... then bolt em on and go. That is, unless you really know what you're doing, otherwise trust in the guys who do.:)

-Mindgame

Originally posted by Mindgame


You might be surprised with the Pro1 CNC heads. I know I was.
I've seen quite a few CNC heads over the years... the CNC stuff from Weld Tech, Chapman, Dart are quite a bit better quality than the run of the mill CNC stuff you usually see.

My porter agrees with you...the diff too with the quality CNC programs and the other stuff is price too. The better CNC programs will cost more money. I dont understand why a lot of people over pay for bottom ends with needless billet parts and dont put the money in the heads :confused:

thats just me though. I'd rather spend 2500-3000 in a set of heads than a billet crank which i wont ever need

I think all I will get is a good valve job and slightly blend the bowls. This should be just fine, I am excited to see their quality, just waiting to hear back from Herbert Performance on pricing.

Thanks

Hunter

you can also check out summit....i remember a while ago they had the CNC'd pro 1's in their catalog. Just search for "dart" on their site and then click on the link that gives all of dart products they stock.

if i remember right the price for the CNC'd darts was like $2400 or so

If i were you though, i'd buy them bare with just the CNC porting. It's probably going to obvious you aren't going to use the springs the supply and retainers so why pay for them?

Damn good point 89.

You'll probably want a better match of components anyway... just buy em bare. They're $1859.98 (#11970040) from Herbert in what I believe is their latest catalog. Plus.. free shipping which is always nice.:)

-Mindgame

actually another head you might want to look into that i wish i would've thought of is the brodix Track 1-X. They have 60/40 valve spacing and do require offset lifters BUT the heads are amazing

StrokedTA on the board here had them on his 11:1 406 with a carb and a baby nitrous cam and it made 658hp on the engine dyno. Thats pretty damn good