LIL SS

iTrader: (9)

Hey John.. Do you have a solid roller?

This might be an interesting test.. I can't use my Solid roller 72cc AFR 225's for some time and I am buying a GMPP intake, 100mm TB and elbow to go with it. You willing to test some things?

You have to buy the head gaskets and other misc parts but it might be an interesting test.. Only thing is, you break it, you buy it..




Here is my take on this conversation.

Any time you have a more restrictive intake track (This includes intake and heads as a package):
A) You would build a given PSI faster
B) You would have more total PSI at peak (Blower car and MBC car, EBC car would stay the same)
C) You might see quicker power under the curve due to charging the intake quicker (3500rpm and bellow for example)


All things equal with a less restrictive intake track:
A) You would not see same PSI as quick
B) You would see less PEAK PSI on a blower car or a MBC turbo car yet could see the same boost on a EBC turbo car if your turbo(s) could suport the extra CFM needed with the better intake
C) You would see more power with less boost
D) You would see more total peak power again given your your turbo(s) can keep up with the new demand of air
E) There would be less heat created helping with detonation potential

02402RAMAIR

iTrader: (8)

has anyone here heard of valve overlap. thats when both intake and exhast valves are open at the same time.more overlap causes boost to drop. your boost just went out the exhaust pipe.

Pro Stock John

iTrader: (34)

I am hydraulic roller.

Wet 1

iTrader: (4)

It surprises me there is so little discussion regarding heads, cams, and intakes in our FI forum. These things are critical for NA engines and are amplified with forced induction. The typical mentality seems to be if you need more power just add more boost and forget about the volume of air flowing through the engine.

The comment about the use of a solid roller is another topic I find interesting. With a solid roller you can have much steeper lobes, with a NA engine this is a huge advantage... is it with FI? I can see how this would benefit greatly on the exhaust side to evacuate the exhaust, but is it as beneficial on the intake side since the incoming charge is being forced in? Does anyone use a solid roller on their FI engine? How much is gained by using one?

It seems to me if all things are equal (including boost pressure), an engine using awesome heads, larger intake (& TB), and an aggressive cam (without to much over lap) is going to make a good amount more power than a similar engine with only good heads, stock intake, and a less aggressive cam. I think we can all agree on this (correct?), with this being said does anyone have a feel for how significant this difference is??? Can it be a 200 hp difference or is it more like a 30 hp difference when we're talking about engines boosted with say ~20 psi of boost?


John, please post your results with your intake swap asap, it might be worthwhile to do the solid roller as well... someone has to be the guinea pig!

LIL SS

iTrader: (9)

Wet 1,

I agree that seems to be most peoples thoughts. With increased boost though, you see increased heat and other issue. Not that I wont attempt to push 25psi from time to time when I'm done.

To answer your question about cam selection, mine should be a very agressive off the seat and .620ish lift on a 224* @ .050 cam. I'm probably going to have Dema Elgin grind me a cam. Something like this I think:

Non split cam
Lift / Duration / Overlap
.006/ 260/ 32
.050/ 224/ -4
.200/ 153/ -75 (This may not be the right .200 number based on the .006 and .050. I was guessing)
.620 lift
114 ICL
114 LSA

My thinking with this is you want to use your heads to their fullest. A off the shelf 224 might do ok, but I think something like I have above would greatly out perform a standard 224 cam matched with my heads.

I went Solid roller for 2 reasons. 1) the more agressive lobe 2) I could spin this motor up higher. Being a T91 348ci, I figured I was going to need the RPM's.

Patrick G

iTrader: (14)

Here's a very academic, but fairly accurate desription of why superior heads and intake benefit forced induction applications.

Let's say you have a stock displacement 346 that makes 400 rwhp. Add a better set of heads and intake and the power increases by 40 rwhp.

So if the rwhp is now 440 rwhp at 1 bar (14.7 psi), then if we add 1 bar of boost, we should theoretically (under ideal conditions) produce double the power or 880 rwhp.

The point is, almost any part that gives you an airflow gain naturally aspirated will give you the same gain in proportion to your boost. In this case, the 40 rwhp gain N/A was worth 80 rwhp at 14.7 psi boost. Of course, you have to account for heat and additional driveline losses, but the formula is sound. Make airflow increases and watch the gains mulitply once you turn up the boost.

speedz06

I make about 520 hp with a mag on my car,430 tq.I am told by trusted industry guys that a good cam other than stock could bring my torque up and hp a little.There is no way that heads are going to bring me to 600hp at the wheels.IMO if I can get a real 30 hp from heads across the board,not just peak,I would do it--can anyone guarantee that?Then lets do it.--Todd

speedz06

Thats a good questiuon you posted--Call 4 well known shops and 50/50 will be for or against heads.

Wet 1

iTrader: (4)

Good reading guys, please keep it coming...

LIL SS,
Sounds like a good call on the cam. I realize you're going stock cubes, but since you're using a solid roller and will be winding it up, could you benefit from a hair more duration or are you afraid you'll bleed of to much boost? Since you're going to spin the hell out of it I'd think the extra duration would help up top.

Patrick,
That was really the info I was hoping to see. Are you 100% sure that formula is solid?

Speed,
You're correct... few seem to have a solid answer to what should be a simple question.

NA$TY-TA

iTrader: (21)

I know Harlan ran a solid roller cam in his old setup and i know Kevin @ Stenod Performance is running a solid roller cam...... Alot of them do it for what was said above plus the other benifit... being able to spin the motor sky high ...allowing them to go farther on taller gears.
Kyle

Patrick G

iTrader: (14)

100% sure. They even have an article about it in the Oct 2005 issue of Popular Hot Rodding. They did a buildup of a 6.0L LS1 and made well over 1000 hp. They have some good formulas in that article.

rjw

iTrader: (3)

I just found this and another similar topic.

Has anyone done a heads only or heads/cam change to find out what the results were?

TIA

TeeKay

Ok, folks, here's some real-world stuff. Not definitive, but anecdotal. 231 V6 - 12 psi (roots) - 270 hp. Add cam with more duration and a tad more lift (better flow). 10.5 psi and 273 hp. Add a smaller pulley - 12 psi and 301 hp. All with 0° KR.

Moral IMO: Increase flow as much as your budget allows, heads, cam, intake, exhaust (but balance them!) and then bring the boost, timing and fuel up to the max with 0° KR (IOW, a good tune). BTW, IC with boost just reduces IAT and staves off detonation (less to 0° KR) so you can run higher boost or more timing or less octane. Think of it that way and you will maximize your setup without a lot of wasted money. I know, I did it just that way. It works. HTH

rjw

iTrader: (3)

When you arrived at 12 psi, were iat's the same as the original setup?

Any difference in MPG or driveability?

Wonder what a set of heads would do for your setup?

Which roots do you have?

TeeKay

Yes, the IAT's were almost identical. Think about it, the temp rise is a function of how much boost is in the manifold, not the CFM. Doesn't that make sense?

MPG? Hell, yeah, it got worse! I got on it a lot more! Seriously, MPG didn't suffer under normal driving, as a matter of fact I got just a little more and drivability was still great since I didn't go to a "radical" cam.

Heads? A lot of guys with the GTP (S/C V6) went to STG II & III heads with great results (they all did a cam BTW) and were able to get 30-50 hp more with the same boost. Now, remember this is with the 231, not the 346! Of course, at that level of modification, it gets harder to draw a definitive parallel because of the variety of setups possible. BIG cam with Stg II heads, lesser cam with STG III heads... well, you get the idea.

Sorry, forgot to mention, stock M90 ported and polished to STG III by ZZP. I did that first. HTH.

rjw

iTrader: (3)

IAT results do make sense.

What did you see from the blower porting? Less heat, more hp, tq or what?

Did they port the outlet, inlet, both? or more?

Any pics? The Ford guys are mostly using Stiegemeyer who used to port for Apten.

Who is ZZP?

You are running 12 PSI on the M90. Are you intercooled (if so, AW or AA) or otherwise? What are your actual IAT's?

TeeKay

I put a ZZP Stage II A2W IC into my GTP. I was able to run the 12 psi with 0° KR. I didn't measure the IAT's after the IC install, but typically the ZZP IC can drop the temp by more than 100 °. IOW 250° to 140° at 14,000 blower rpm. I pulled the drivetrain, IC and all, last November to start the hybrid in my sig.

The M90 by definition pushes 90 CI per revolution. The main benefit was better adiabetic efficiency which translated to about 10°+ lower IAT's. The porting is all over to increase efficiency of flow. A little here, a little there. The main porting is on the exit radii of the blower and opening up the intake manifold. It makes quite a difference on the 3800.

www.zzperformance.com

They are a 3800 go-fast shop in Michigan working on W-bodys. They have a FWD GP in the 9's. That pretty good for a 3.8L, huh?

rjw

iTrader: (3)

Impressive for sure

What speed are you spinning the M90?

What heads/cam are you suing in your new 383?

TeeKay

We're kinda off-thread, so my post about flow first, then boost and timing is still what I think. lol

I was running a 2.5x pulley for 16K+ blower rpm.

The stroker has PP Stage II LS1 heads (reworked) and a 224/228 - 114 .581/.588 lift.

Nice talking to ya'

white2001s10

iTrader: (4)

IMO the intake side theoretically doesn't matter as much when running boost. The increased pressure difference across the intake valve would be the major factor in filling the cylinder under boost conditions.

The greatly increased mass moving past the intake valve changes the I/E ratio across the head. This means that big improvements would be welcome on the exhaust as far as the head goes.
I believe the increased exhaust volume taking longer to evacuate the chamber could be a major hinderance to any induction pulse created by the intake port. In this case a higher velocity may theoretically be an advantage.

If you increase the intake port flow of the head, you would also get a corresponding drop in boost pressure, and that much less heat energy in the intake charge. The cooler temp should be able to produce more power with roughly the same amount of mass passing by the intake valve. The drop in boost however would reduce the pressure difference across the intake valve and you could see a small reduction in cylinder filling. In the end you might break even on the power production. I think this is what TeeKays real-world example shows. The CFM remains about the same and therefor the mass passing the intake valve is about the same.

This almost suggests that it doesn't matter what you do to the intake port if you can just as easily produce more boost. You do get into deminishing returns as the boost numbers increase, so there is a valid argument for using larger intake ports when very high power levels are needed. For more reasonable levels of power I think it's easier and cheaper to just turn up the boost.

Also note that sometimes real-world doesn't like to follow the best theories. An example cited by David Vizard when dyno'ing a customers turbocharged SBC producing 1000+ HP -Vizard said the customer had removed the divider wall from between the intake ports in the head and manifold, and the engine seemed to respond positively to that modification. Vizard himself was unable to conduct a test on that specific mod, and his dyno had a 1000 hp limit.
Apparently there are cases where a boosted engine will respond well to a change of the intake port.

I'd assume that this example was a very high level of boost. The pressure difference across the intake valve may have the charge moving into the cylinder so fast (especially with a late intake opening) that it was an advantage to have a large area of charge available right behind the valve.

It certainly is interesting to think about.