GN1 irons vs. 8445

[Walker231T]

How about the weight saving over the aluminums vs the irons? Isn't that a big factor when considering the aluminums over the irons? Assuming you don't mind spending the extra $$ for the aluminums.

 

[musclecar neal]

The weight savings on a typical application will not decrease ET very much. It would help front to rear bias and aid wieght transfer allowing a better 60' that is where the lower ET would come from.

 

[david buschur]

I have never looked but am pretty shocked at the flow numbers I am seeing. You guys mean to tell me a good ported head for the Buick is only flowing low 200 cfm's on the intake side and under 200 on the exhaust?

What brand flow bench, how many inches of water and at what lift is this?

Just curious. I am suprised how little they flow for the power the cars make.

I guess the Japanese really do have their stuff figured out

David Buschur

 

[JToups386]

David --- It's also an example of "area under the curve". They may flow only 200-ish, but when having 20+ psi forced through them, and making all their power from around 2800-5200, they seem to flow just fine for the requirements we have. They flow 200 for the majority of that range.
Also remember, we're only filling up 6 holes with a total displacement of 231 cid (for most of us), and not trying to fill up 350 - 454cid...

BTW, I looked on your website at your/your company's Talon accomplishments. Pretty freakin' amazing! Hats off to you!

 

[david buschur]

The 20 plus psi has very little to do with the head flow. I use to think the same thing. Make the port as big as possible and the hell with the flow bench, the turbo is going to push it in there regardless. After being told my thinking was REAL OLD school we did a lot more testing with the flow bench and dyno/track. The guy was correct. The head needs to flow on the bench first as it will only benefit when it is forced through.

As for flowing the same the entire way, not sure what you mean there. RPM has nothing to do with it if that is what you were referring to.

At .100 lift the head isn't going to flow nearly what it does at .500 lift. That is why I was asking if anyone new what lift the 200 cfm flow numbers were from.

Our race stuff is only 122 cubic inches. On a flow bench that has been proven to be quite a bit slower than Super Flow benches we are flowing 285 cfm on the intake and 280 cfm on the exhaust ports. This is at 28 inches and .450 lift. The engines are making over 800 wheel horsepower. I have run 7.81 at 175 mph with this head in my tube chassis car. In our street car we have run 8.79 at 151 mph.

I was just wondering if anyone had some actual flow bench stats for the lift of the cam and inches the head was flowed at.

David Buschur

 

[2 SLOW]

David,

You think thats bad, the stock untouched heads only flowed about 180 ( I think) and stock cams only lift .40x ( I think also ). Have a friend that about three years ago with a stock motor that has never had the intake off, ran 10.81 and 10.84. Had different IC, converter, PT54 turbo, etc. So yeah they are amazing. I bought my 87 new and at the time never dreamed it would ever go 10's and be perfectly streetable. So welcome to the peanut motor club.

 

[david buschur]

I too have been around the TR's since 1986-87. Been racing the Mitsubishi 4 cylinders since 1989. I am just shocked at how poor the head flow numbers are, I had never read them before.

I have a set of stock heads on my car that we put a mild port job on at the shop. Cleaned up the bowls and runners. The car runs great, made 426 hp and 512 ft lbs to the wheels at 19 psi of boost. I also have a set of Champion CNC ported heads on a serious 109 block that is sitting complete on an engine stand in my garage. I never asked about the flow numbers when I bought the heads.

Anyone know the flow numbers on a set of Stage 2 heads? Ron's car made 1485 hp with a set of ported productions Stage 2's the flow on them has to be TONS higher than the stock GN heads, no comparison looking at them.

David Buschur

 

[BEATBY6]

Dave my Chapman stage 2 heads flowed 340 on the intake and 255 on the exh. at .700 What does a your head flow on your 7 sec DSM?

 

[2 SLOW]

David,

Sorry no disrespect intended. My stage 2 heads flowed about 332 @ .600 lift. And yeah the ports are like golf balls on stock or GN1 and tennis balls on stage 2. And a few years ago at Woodburn, Ore. Ryan Guy ran a 9.99 with only mildly ported stock heads on a heavy car. Stock block, 76 turbo and all the rest. Just pointing out how amazing these little heads are.

 

[JToups386]

Dave --- you are correct in your reply to me. I did not do a good job of explaining my point. It's late, and I should be asleep, as opposed to talking tech at 2am.
I realize that higher boost doesn't mean more power, but rather, a less efficient intake/head flow, and the inability of the whole system to move air through it more efficiently. You are correct in that many folks don't realize that an efficiently flowing system can make more power w/ less "boost".

Also to your point about head flow on your 4-banger --- don't y'all have 4 valves per cylinder?

Someone also mentioned an estimated 180cfm on a bone stock set of 8445's, which I believe is actually a very liberal number.

These tiny little chunks of iron seem to flow plenty well, whether it's 200cfm on one guy's bench, or 220 cfm on someone else's bench. Bottom line is --- they/total package work... And for some of these guys, the ol' 8445's have seen 9 sec' slips, carrying 3400 lbs down the track. Not too shabby!

Alright, great thread. However, I'm hittin' the sack now. Nice chattin' with ya'.

 

[BoostKillsStres]

I believe I've read that stock 8445's only flow in the 150-160 range on the intake bu tnot totally sure.

Here's some flow numbers from a nicely ported set of 8445's:
.200 - 124 intake, 104 exhaust
.300 - 179 intake, 135 exhaust
.400 - 202 intake, 149 exhaust
.500 - 209 intake, 161 exhaust

This is at 28 inches of water on a 3 inch bore plate with no fixtures on the intake and exhaust ports.

HTH

 

[2 SLOW]

Yeah I was just guessing from a bad memory. I have the numbers some place but haven't looked at them in years. I certainly could be off. The point is , of course, that some people have gone real fast pushing 30+ lbs. boost through stock heads.

 

[QuickWrench]

laz said:

I guess a good head porter should do our iron champion heads they only flow 199@450 lift intake and 175@550 lift exhaust but there good for 9.64@141.18.

\
Holy cr@p. D@mn, that's impressive.

I hate to ask the obvious question here, but...Laz, are your Champ's off-the-shelf Iron CNC's? I had taken it for granted that you'd done a one-off set of killer irons.

Not trying to pry any secrets here, but what have you found to be the upper RPM range with acceptable power for a max-boogie set of irons?

Thanks.

 

[david buschur]

beatby6,
Wow, the Stage 2 head flow a hell of alot better. Thanks for the numbers. You asked what the head flows on my 7 second DSM. Well, as I said the flow bench we use is slow compared to other benches. I also only run a cam that is .410 lift on the intake side and .396 on the exhaust side. I have no idea what it would flow if I opened the valves to .700 lift. Flowing the head to .450 lift though we get in the 280 cfm on both the exhaust and intake sides of the head.

2slow,
More proof of how good the Stage 2 heads are, 332 at .600 is nice. No offense taken by the way.

jtoups386,
Yes, the Mitsubishi head has four valves, small valves but there are four of them.

Boostkillsstres,
Thanks for the actual numbers. How do those compare to a set of off the shelf Champion CNC ported cast iron heads? That is if you happen to know.

Thanks guys, nice conversation.

David Buschur

 

[BoostKillsStres]

I don't seem to have Champ iron's flow data but I know of a site that might, just have to find it, found it..at the bottom.. Here's some more interesting flow data I had stashed away:

Taken from the TBN-The Source Newsletter...stock heads.
Intake (lift, flow rate @ 28 in H2O)
.100, 51.7
.200, 108.2
.300, 149.0
.400, 152.2
.500, 155.1
.600, 158.4

Exhaust (lift, flow rate @ 28 in H2O)
.100, 45.1
.200, 83.9
.300, 101.2
.400, 108.2
.500, 111.1
.600, 114.85(this one is interpolated at this lift)

=============

All on intake at 0.500" lift:

GN-1 out of box..................................230 cfm

GN-1 Champion ported.......................257 cfm

=============

Champion Heads: No Port Work

Intake valve size: Stock Champion
Exhaust Valve size: Stock Champion
Pressure 28"

Intake
V-Lift CFM
.2 127
.3 181
.4 211
.5 223
.6 224
.7 227
.8 228

Exhaust
V-Lift CFM
.2 108
.3 136
.4 154
.5 164
.6 168
.7 171
.8 173

Links to some of above data:
http://www.geocities.com/kdslaby/Tech_Page_Glossary.html

 

[Snorman]

I'll throw my numbers out there...
These are ported irons, 1.775" intake/1.500" Manley severe duty valves
1.25" titanium retainers
1.25" LT1 springs @ 1.735"

These were flowed on a Superflow 1020 bench at 28", I'm not sure on whether a fixture was used or not.

Before-stock
Lift Intake Exhaust
.050 38 33
.100 63 56
.150 89 74
.200 116 88
.250 136 100
.300 142 106
.350 146 110
.400 151 112
.450 151 113
.500 152 115

After-Stage III port
Lift Intake Exhaust
.050 39 42
.100 81 79
.150 116 103
.200 149 128
.250 180 146
.300 198 158
.350 215 164
.400 220 170
.450 224 174
.500 227 179
.550 227 183

They're not on the car yet, I'm going to gradually move into them this spring after stepping up a few other things.
S.

 

[S2V6RACER]

Originally posted by laz
I guess a good head porter should do our iron champion heads they only flow 199@450 lift intake and 175@550 lift exhaust but there good for 9.64@141.18. Flowbenches have different flow numbers in different places but champion iron heads are hard to beat and very consistent. I think champions irons offer a good return on investment also . Try and sell a set of heads done by your local shop and see what there worth down the road .

Second opinon, I am on Laz's side here.

My irons have no chamber work done what so ever and do not even have the EGR's plugged. They have went 9.86 with a 1.48 60'. I have pulled 1.366 60' at Norwalk back in 02, so do the math on what the E.T would be.

You must flow everybodys heads on the same flow bench to take #'s and compare them. There are many ways #'s can be tweaked.

 

[gnsrule]

Last year we built a unit simlar to what Jason used to develop the Power Plate. We wanted to see flow dynamics in the stock lower intake with and without the PP. A good friend is an engineer for Pratt&Whittney so we used thier develoment lab for around 60 hours doing testing. We used the stock intake as a baseline and made about 30 interations with the PP for a precision plenum and other plates we made along with mods to the plelum that we wanted to try based on naturally aspirated theories. It really surpirsed us when the PP equipped set up yeilded the most consistant runner to runner readings except for 3 set ups we built with a highly modded lower with no plate.

Can you elaborate on the highly moded lower w/ or w/out a PP ?? Alot of us are running a Champion ported lower. I'm currently running a PP w/ a Precision upper, and a champion ported lower.
Thanks,
Craig