Peak Power Too Low??
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Peak Power Too Low??
I had a motor dynoed the other day. It's a 383 SBC, Canfield ported 195's, RPM AirGap, 750 DEMON Vacuum secondaries, 11:1 compression, gapless rings, beehive springs, COMP hydraulic roller 242/248 @ .050 .541/.562 lift
The motor made peak power @ 5600 rpm. I was expecting a peak around 6000-6200. Does 5600 peak sound low for such a big cam in a 383?
The motor made peak power @ 5600 rpm. I was expecting a peak around 6000-6200. Does 5600 peak sound low for such a big cam in a 383?
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
That intake manifold and carburetor is going to hold it back a little bit. If you want to raise the power peak go to a single plane manifold and an 800CFM carb. Do you have headers on this thing? Going larger on pipe diameter and shorter on length will raise it also.
BigBlockk
Later.....
BigBlockk
Later.....
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
Here is a CFM calculator to help YOU decide...
A 383 at 6500 RPM and 100% Volumetric Efficiency can only pump 720 CFM.
Typically most engines are closer to 80 to 85% Volumetric Efficiency.
The manifold is more of a determining factor here.
Are your current intake manifold and heads port matched?
http://www.4secondsflat.com/Carb_CFM_Calculator.html
Typically most engines are closer to 80 to 85% Volumetric Efficiency.
The manifold is more of a determining factor here.
Are your current intake manifold and heads port matched?
http://www.4secondsflat.com/Carb_CFM_Calculator.html
Le Mans Master
Joined: Jan 2006
Posts: 8,319
Likes: 7
From: Wilmington DE, Drive it like you stole it, 68 327 4 speed coupe
Originally Posted by fl_rider
A 383 at 6500 RPM and 100% Volumetric Efficiency can only pump 720 CFM.
Typically most engines are closer to 80 to 85% Volumetric Efficiency.
The manifold is more of a determining factor here.
Are your current intake manifold and heads port matched?
http://www.4secondsflat.com/Carb_CFM_Calculator.html
Typically most engines are closer to 80 to 85% Volumetric Efficiency.
The manifold is more of a determining factor here.
Are your current intake manifold and heads port matched?
http://www.4secondsflat.com/Carb_CFM_Calculator.html
Say it aint so
....... the factory Qjet flows more than that
Last edited by sweethence; Feb 7, 2006 at 12:07 PM.
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Originally Posted by BigBlockk
That intake manifold and carburetor is going to hold it back a little bit. If you want to raise the power peak go to a single plane manifold and an 800CFM carb. Do you have headers on this thing? Going larger on pipe diameter and shorter on length will raise it also.
BigBlockk
Later.....
BigBlockk
Later.....
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Originally Posted by fl_rider
A 383 at 6500 RPM and 100% Volumetric Efficiency can only pump 720 CFM.
Typically most engines are closer to 80 to 85% Volumetric Efficiency.
The manifold is more of a determining factor here.
Are your current intake manifold and heads port matched?
http://www.4secondsflat.com/Carb_CFM_Calculator.html
Typically most engines are closer to 80 to 85% Volumetric Efficiency.
The manifold is more of a determining factor here.
Are your current intake manifold and heads port matched?
http://www.4secondsflat.com/Carb_CFM_Calculator.html
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Safety Car
Joined: Oct 2004
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From: Youngstown Ohio
Just as a "virtual engine", my DynoSim shows peak HP at 6000 rpm and peak torque at 4500 rpm based on your engine specs.....my own engine is very similar but with slightly less cam and it pulls strongly to 6500 rpm with the RPM Air Gap and Demon 825 carb. The peaks were the same when I had an Edelbrock 750 also.
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Does anyone think the Canfield195's are too small for the cam? I'm considering going to the 215's or 220's. I'm thinking about a WP single plane and a Mighty DEMON 825 for track days too.
The ported 195's may be for sale soon.
The ported 195's may be for sale soon.
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Originally Posted by nastee383
Does anyone think the Canfield195's are too small for the cam? I'm considering going to the 215's or 220's. I'm thinking about a WP single plane and a Mighty DEMON 825 for track days too.
The ported 195's may be for sale soon.
The ported 195's may be for sale soon.
Instructor
Joined: Feb 2006
Posts: 144
Likes: 0
heres the dyno on my 383, peaks at around 6000RPM
its with Brodix track 1 heads and EB TorkerII manifold.
Speeddemon 750 mec sencondaries
Cam is a solid roller
Valve Lift:
Intake = .562
Exhaust = .562
Duration @ .015"
Intake = 268
Exhaust = 268
LC = 110
http://i32.photobucket.com/albums/d3...t/0d458076.gif
its with Brodix track 1 heads and EB TorkerII manifold.
Speeddemon 750 mec sencondaries
Cam is a solid roller
Valve Lift:
Intake = .562
Exhaust = .562
Duration @ .015"
Intake = 268
Exhaust = 268
LC = 110
http://i32.photobucket.com/albums/d3...t/0d458076.gif
Last edited by PNK; Feb 9, 2006 at 12:17 PM.
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Originally Posted by nastee383
Does anyone think the Canfield195's are too small for the cam? I'm considering going to the 215's or 220's. I'm thinking about a WP single plane and a Mighty DEMON 825 for track days too.
The ported 195's may be for sale soon.
The ported 195's may be for sale soon.
Another thing to look at is timing. High swirl heads require 6-8 degrees less total timing than old heads. Dyno runs have found the best power in the 32 or so degrees max the best.
Do you have any head flow info on your heads? Because 195's with @265+ cfm intake should support over 500 hp.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Put a Victor E or a Super Victor CNC on that engine and you are gonna shift the peak HP to a higher RPM!
Even though the Performer RPM is better at lower RPM, you can still expect a 10+ HP gain with a performance single plane intake, preferably with a spacer!!
Even though the Performer RPM is better at lower RPM, you can still expect a 10+ HP gain with a performance single plane intake, preferably with a spacer!!
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Originally Posted by gkull
I saw your dyno figures the other day. I would have expected a higher peak hp rpm. Is it possible that your into valve float? i just don't think that you can use the word race car and H-rollers in the same sentence. I have the exact same cam on my 427 small block and it zings to 7000 rpm where I set my rev limiter. I just sold my H-rollers and installed S-rollers. I'm also just running a 750 cfm. I could probably run a 600 - 650 cfm and only be down a few poneys.
Another thing to look at is timing. High swirl heads require 6-8 degrees less total timing than old heads. Dyno runs have found the best power in the 32 or so degrees max the best.
Do you have any head flow info on your heads? Because 195's with @265+ cfm intake should support over 500 hp.
Another thing to look at is timing. High swirl heads require 6-8 degrees less total timing than old heads. Dyno runs have found the best power in the 32 or so degrees max the best.
Do you have any head flow info on your heads? Because 195's with @265+ cfm intake should support over 500 hp.
They used 113 race fuel so I don't know if that had any adverse effect. They started with 35 total timing and jumped to 40. I would have rather started about 32 and increased in smaller increments. It was my first dyno experience and I was just so glad the thing started up after all the problems I'd had with it. I probably didn't didn't give my input like I should have but experience is a good teacher. Next time I'll be more involved in what's going on.
I don't have exact flow #'s on the heads but I assume they're marginally better than "out the box" Canfield195's. So you're right, they should support 500+hp.
Thread Starter
Melting Slicks
Joined: Apr 2000
Posts: 2,145
Likes: 1
From: Ft. Walton Beach, Fl USA
Originally Posted by GrandSportC3
Put a Victor E or a Super Victor CNC on that engine and you are gonna shift the peak HP to a higher RPM!
Even though the Performer RPM is better at lower RPM, you can still expect a 10+ HP gain with a performance single plane intake, preferably with a spacer!!
Even though the Performer RPM is better at lower RPM, you can still expect a 10+ HP gain with a performance single plane intake, preferably with a spacer!!
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Originally Posted by nastee383
If I go with a single plane it'll be World Products. I've read alot of good things about their SBC single plane. Besides I don't want to just shift everything up in the rev band. I think it should be making more power overall. By 5600 this motor with the parts in it should be at 485-495hp and should peak at around 6000-6200 at 500-505hp. It should be making 500+ft lbs at about 4600. The motor was dyno'd with the full serpentine accessory drive including alternator, power steering pump and water pump but I don't think that made much of a difference.