Head flow numbers...look at this:
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From: Orlando
Head flow numbers...look at this: Got my MTI 2E 5.3 heads Thursday afternoon. Obviously, the box was ripped open so I could inspect my new toys...anyway, here's my question. I was looking at the flow sheet included in the box and I'm not sure if what I'm seeing is an issue or not. Now, the disclaimer is that I realize that flow numbers only tell part of the story about how a head will perform, but this exhaust flow number looks a little low to me. Tell me what you all think:
On the top of the flow sheet are the traditional words about the correction to 28" and all that. Next to it, the sheet indicates "1st cyl, Int & Exh CFM" and the flow numbers at .650" lift show "Cyl 1 Int CF 311.4" and "Cyl 1 Exh 199.2".
Now the question...does that exhaust flow number of less than 200 seem quite a bit low to you? At .550 lift, the exhaust flow is only about 180 or so. Is this low or is it just me? I'm at a loss so let me know what you think. If there's an issue, I'll try to resolve it soon with MTI. Thanks for the insight.
On the top of the flow sheet are the traditional words about the correction to 28" and all that. Next to it, the sheet indicates "1st cyl, Int & Exh CFM" and the flow numbers at .650" lift show "Cyl 1 Int CF 311.4" and "Cyl 1 Exh 199.2".
Now the question...does that exhaust flow number of less than 200 seem quite a bit low to you? At .550 lift, the exhaust flow is only about 180 or so. Is this low or is it just me? I'm at a loss so let me know what you think. If there's an issue, I'll try to resolve it soon with MTI. Thanks for the insight.
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From: Marysville, OH
*Super Flow 1020 Flow Bench Ratings
Chamber(LS6)
64.45
Flow tested on a 3.905 bore LS6
Chamber(LQ9)
71.06
------------.100--.200--.300--.400-.500-.550-.600
Int_cc------- 72-- 140---202--244--280--291--304
Exh_cc------ 65-- 124---160--196--220--226--229
Those are from PP website, LS6 style stage II with a 225 and 83 int / exh CC.
Below are Stage II #'s with 213 / 78 - INT/EXH CC's
Super Flow 1020 Flow Bench Ratings
Chamber_cc 66.67
---------------.100 .200 .300 .400 .500 .550 .600
Int_cc ---------67--133--194--242--274--290--296
Exh_cc -------- 61--108--147--183--205--213--220
I am no expert but those "seem" low for ported LS1 heads, I would not worry about them until you have your car strapped to a dyno. If they do not perform there then I would be pissed.
Chamber(LS6)
64.45
Flow tested on a 3.905 bore LS6
Chamber(LQ9)
71.06
------------.100--.200--.300--.400-.500-.550-.600
Int_cc------- 72-- 140---202--244--280--291--304
Exh_cc------ 65-- 124---160--196--220--226--229
Those are from PP website, LS6 style stage II with a 225 and 83 int / exh CC.
Below are Stage II #'s with 213 / 78 - INT/EXH CC's
Super Flow 1020 Flow Bench Ratings
Chamber_cc 66.67
---------------.100 .200 .300 .400 .500 .550 .600
Int_cc ---------67--133--194--242--274--290--296
Exh_cc -------- 61--108--147--183--205--213--220
I am no expert but those "seem" low for ported LS1 heads, I would not worry about them until you have your car strapped to a dyno. If they do not perform there then I would be pissed.
http://www.motorsporttech.com/c5_engine01.asp
The flow chart for the LS1 MTI S2E shows 200+ cfm on exhaust at 550 lift and well over 200 at .600 lift.
I'd call Jayson and talk with him.
The flow chart for the LS1 MTI S2E shows 200+ cfm on exhaust at 550 lift and well over 200 at .600 lift.
I'd call Jayson and talk with him.
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From: Orlando
That's what I was thinking, too. Better to say something beforehand. The only difference I noticed in those flow sheets compared to mine is that mine only seems to show flow rates on one cylinder only and isn't an average of the entire head. The ones on the website appear to be an average of the whole head. I suppose I'll call him this week. Thanks, everyone. Any other thoughts out there?
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From: bronx ny
is it flowed with or without a pipe, what I have gathered the ls1 ex ports flow around 200 without a pipe and you can add a solid 25-30 cfm with a pipe. Also flow benches have a variance in readings, a head that flowed 250 on TEa's bench may only flow 230 on MtI's. Cab you share all the flow numbers with us from 100 lift up
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From: Texas, it's like your state, but better.
dude, even if they are, those are perfect for a 346 ci motor. you do not need 240+ cfm on the exhaust side. you're not mooving that much air. do you realize that your exhaust side flows about as much as a stock LT1 intake port? 20+ more than a e7 5.0 intake port? thats huge flow!
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From: Orlando
Thanks for the insight, Vents. When it comes to numbers, I kind of have the general idea of how they apply to the application but I lack the know-how of the way they actually work into the whole equation. I see all of the porters showing this 220+ exhaust CFM numbers and was thinking that there may have been something lacking in the heads I got. I am fairly certain that MTI wouldn't send out something that didn't fit their criteria when they put a head on a bench and numbers didn't jive. Again, the thing that caught me off guard was the fact that the 200 CFM was at .650" lift! At .550, they are ~ 190 CFM so I'll assume that's still respectable out of them.