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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2168071
10/04/16 11:18 PM
10/04/16 11:18 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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checkout Andys build in the archives, 470 cubes 550 horse (iirc). used std 68-70 BB HP manifolds, 3" mandrel bends.
live every 24 hour block of time like it's your last day on earth
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2168126
10/05/16 12:42 AM
10/05/16 12:42 AM
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Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
fast68plymouth
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I would look at it from another perspective.
If you're building it to compete in a class, then you should determine how much power you need to be competitive, and build to that target goal.
If it's just a street car, then it will likely come down to the same determining factors that go into many street builds...... Which usually revolve around the theme of what your tolerance is for how rowdy it can be. In this scenario, you build it according to what you think you can live with, and that engine combination just makes what it makes.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: dave571]
#2168257
10/05/16 10:52 AM
10/05/16 10:52 AM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
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I Live Here
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Port match goes a long way.
As said by Robert, check out Andy F's build Along with extrude honing the exhaust manifolds
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: DAYCLONA]
#2168288
10/05/16 11:59 AM
10/05/16 11:59 AM
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Joined: Jan 2003
Posts: 75,004
U.S.S.A.
JohnRR
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U.S.S.A.
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Port match goes a long way.
As said by Robert, check out Andy F's build Along with extrude honing the exhaust manifolds A lot of money for a small gain, so unless he is building to race in a in FAST type class, and needs every last HP, it's really a waste of money. I think people that have done it saw maybe 5hp, it cost over $500 last time I saw someone talk about it and that was maybe a decade ago ? Listen to fast68plymouth , he has been involved in a number of builds for this. My experience is the port openings on the manifold are a lot smaller than the ports on the head , especially if the head is opened up to the gasket , port matching the manifold on both the inlet and the outlet to the head pipe , along with smoothing as much as you can reach in can't hurt. andyF didn't do much of anything to the manifolds he ran, maybe port matched , but he did use a pass side without the flapper valve setup, I'd remove that if the crossover is blocked.
running up my post count some more .
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2169414
10/07/16 01:17 AM
10/07/16 01:17 AM
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Joined: Mar 2005
Posts: 1,545
Seattle, WA
375inStroke
OP
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Seattle, WA
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Thanks for the replies. Is there any concern with plug wires on #6 and #8 with angled plugs on manifolds? Using AndyF's motor as a guideline, would something like the Trick Flow 240 heads be too big for this type of motor? Would a split pattern cam be something to avoid, or just keep the intake around the 240° to 245°@.050", and not worry too much about it?
Last edited by 375inStroke; 10/07/16 02:33 AM.
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: dogdays]
#2169426
10/07/16 01:50 AM
10/07/16 01:50 AM
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Joined: Jan 2003
Posts: 8,395
Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,395
Highland, MI.
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Sparky, your post contradicts itself. Extrude honing ($100 per horsepower) is the opposite of bashing in the header pipes.
Here's what I take from the video: The extra flow advantage from headers is only a small component of the total power gain. Most of the power gain comes from the pressure wave tuning.
This is the reason that shorty headers don't gain much over manifolds. Not enough length separating the pulses.
To the OP, I would say follow AndyF's examples.
Recently I have seen quite a few dyno tests with Volumetric Efficiency numbers over 100% for quite a high percentage of the operating range. It should be physically impossible for a piston to suck in more than its total swept volume. The difference is in tuning the pressure pulses, used to be called ram tuning. Isky Cams touched on it in the early '60s by talking about 5-cycle cams. The fifth cycle was overlap. I am pretty sure that at least a few of early hot rodders like Ed Winfield were playing with this back in the '40s.
R. Sparky? OKAY...............
No Man With A Good Car Needs To Be Justified
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2169492
10/07/16 09:04 AM
10/07/16 09:04 AM
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Joined: Feb 2005
Posts: 4,313
Prospect, PA
BSB67
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master
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Prospect, PA
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If you can us the TF, I would suggest that. Others have been able to make other aftermarket aluminum angle plug heads work with manifolds, but don't know anyone doing it specifically with the TF. I would assume they would be the same.
If you don't want to leave any power on the table, You should get serious about piston configuration, compression ratio, cam event timing, and cylinder pressure to maximize power at your elevation. A guy like Dwayne Porter can step you through all of this.
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2169636
10/07/16 02:38 PM
10/07/16 02:38 PM
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Joined: Jan 2003
Posts: 31,023
Oregon
AndyF
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I Win
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Thanks for the replies. Is there any concern with plug wires on #6 and #8 with angled plugs on manifolds? Using AndyF's motor as a guideline, would something like the Trick Flow 240 heads be too big for this type of motor? Would a split pattern cam be something to avoid, or just keep the intake around the 240° to 245°@.050", and not worry too much about it? If I was building a new motor today for my car I'd use the Trick Flow heads. I don't see any reason not to other than the angled spark plugs which are not super friendly with the HP manifolds. If you read my cam testing article in the tech archives you'll see that cam selection is a little tricky. If you go too big you lose bottom end power and the manifolds prevent making top end power. If you go too small you make a lot of torque but you give up top end power. I had to test a bunch of cams before I figured out what my engine wanted. Dwayne is a good guy to ask for a cam recommendation. He has a fair amount of experience with manifold engines.
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2169762
10/07/16 06:19 PM
10/07/16 06:19 PM
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Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
fast68plymouth
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Part of building power with exhaust manifolds is trying to keep the intake port velocity up without the benefit of exhaust scavanging.
The bigger the intake port, and valve, along with more low lift flow(which almost always means more flow in both directions), relative to the size of the motor, the harder it is to build velocity at moderate engine speeds.
To me that means that you'll want to make the motor as big as is practical to use the TF head with it's fantastic low lift flow and 2.19 valve in this type of application.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: BSB67]
#2169767
10/07/16 06:27 PM
10/07/16 06:27 PM
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Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
fast68plymouth
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600 hp is doable. It is a bit of what you are willing to do or spend to get there, but it's not rocket science either. I think it's also worth noting that headers definately work. You'll spend a lot of $$$ on other areas of the build to make up for what you're losing by not running headers.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: fast68plymouth]
#2169785
10/07/16 07:02 PM
10/07/16 07:02 PM
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Joined: Jan 2003
Posts: 31,023
Oregon
AndyF
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Part of building power with exhaust manifolds is trying to keep the intake port velocity up without the benefit of exhaust scavanging.
The bigger the intake port, and valve, along with more low lift flow(which almost always means more flow in both directions), relative to the size of the motor, the harder it is to build velocity at moderate engine speeds.
To me that means that you'll want to make the motor as big as is practical to use the TF head with it's fantastic low lift flow and 2.19 valve in this type of application. That is a good thing to go ahead and point out. When I switched from my 470 shortblock to a 512 shortblock I also changed from RPM heads to CNC ported Mopar 452 heads. I think that a 512 would be big enough to work with the TF 240cc heads but you might want to be even bigger than that to keep the velocity up. You can spend a ton of money figuring it all out that is for sure!
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2169820
10/07/16 08:05 PM
10/07/16 08:05 PM
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Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
fast68plymouth
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I Live Here
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At lower engine speeds, keeping the velocity of the air high as it discharges around the intake valve while at the lower lifts(during the overlap period when the piston is moving in the "wrong direction" as far as the intake port is concerned) is easier to accomplish when the valves are smaller rather than bigger.
Like with most things horsepower related, there is going to be a crossover or tipping point for each combination.
With regards to intake valve discharge coefficient(i think especially in a restricted exhaust application), too big of a valve allows for more reversion, and too small of a valve limits peak power output.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: How much can I build a motor with HP exhaust manifolds?
[Re: 375inStroke]
#2170773
10/09/16 09:01 AM
10/09/16 09:01 AM
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Joined: Mar 2005
Posts: 1,545
Seattle, WA
375inStroke
OP
Special needs person
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OP
Special needs person
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Posts: 1,545
Seattle, WA
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This car is a 1964 Dodge 880. I can't figure out what to call this body. It's not a C-Body, and it's not a Forward Look body, but it shares much with that earlier style engineering. I have not found anybody that has gotten a set of headers that will fit this type of car. The steering box is right against the firewall. The driver's side manifold is a center exit, like a truck. I think I can get B-Body HP manifolds to fit, but if anyone knows if long tube headers will fit, let me know. I've even seen people have problems with shorty headers in this style of chassis, but I'm open to suggestions.
Last edited by 375inStroke; 10/09/16 09:07 AM.
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