Engine porn

jon coleman

Well-Known Member
Joined
Jan 17, 2019
Posts
10,882
RDC Crypto
6,584
Location
sandiego
here's some german porn, Vasek Polak 45 ' bat mobile', csl, ( sounded frikken evil), my strut brace fab😀👍
 

Attachments

  • th.jpeg
    th.jpeg
    5 KB · Views: 0

Slippery P

Well-Known Member
Joined
Dec 8, 2007
Posts
2,814
RDC Crypto
3,282
Location
Valley Center CA.
There is an injector in the runner being tested, but the other runners and various holes were not plugged. With the victor, I could feel air drawing in all over the place. But I was also surprised that it reduced flow through the head as much as it did, from 295 cfm bare to 267 with the victor on. Is that typical? I thought the victor might actually increase combined flow. Of course it's irrelevant, since an engine needs a manifold, and the victor was 40 cfm better than the stock one. Stock mani combined flow was only 220 cfm, and that's after a ton of work deburring, port matching, and line of sight blending. In fact I had to build up the outside with weld in places as I kept grinding through. I think the new 454 with the head and mani work, plus bigger injectors, cam, a 0411 corvette ecm and headers will make 400+ at the crank and hopefully 350 at the wheels, and pass az emissions. Do you have a chassis dyno too?
My experience has found better results flowing the manifold, head combo, when all the other runners are taped off at the flange. Don Losito told me that’s how it has to be done, and when Losito tells you something, you do it. 😂
Kinda opens a can of worms though because at that point why leave out the throttle body, right?
I usually take the numbers from the manifold head combo with a grain of salt, being that unless it’s an 8 stack individual runner manifold set up there are too many variables in how the air travels through a plenum style or single plane 4500 style manifold with out replicating the dynamics of a running engine, reverb, cylinder scavenging etc. It’s all good info, but in my opinion the head numbers are the most important. Yes we have a chassis dyno,
 

jon coleman

Well-Known Member
Joined
Jan 17, 2019
Posts
10,882
RDC Crypto
6,584
Location
sandiego
i was told most important is each intake length is the same& same volume, i got that after i asked an engine dood why old can am era engines had different length& velocity stack dimensions, it was thought to spread out the tork band, but it hurt horsepower , oh well, its an ongoing r&d that costs lottsa cash👍(imagine going 240 mph in an ALUMINUM gas tank with a800-1200 hp engine bolted to the back with just a 1-1/2" thin wall 'roll hoop'...
 

Attachments

  • th (10).jpeg
    th (10).jpeg
    6 KB · Views: 0
  • th (9).jpeg
    th (9).jpeg
    6.2 KB · Views: 0
  • th (8).jpeg
    th (8).jpeg
    3.9 KB · Views: 0
Last edited:

Slippery P

Well-Known Member
Joined
Dec 8, 2007
Posts
2,814
RDC Crypto
3,282
Location
Valley Center CA.
i was told most important is each intake length is the same& same volume, i got that after i asked an engine dood why old can am era engines had different length& velocity stack dimensions, it was thought to spread out the tork band, but it hurt horsepower , oh well, its an ongoing r&d that costs lottsa cash👍(imagine going 240 mph in an ALUMINUM gas tank with a800-1200 hp engine bolted to the back with just a 1-1/2" thin wall 'roll hoop'...
Correct, if you look at the inside of one of these big block manifolds, cylinder 3&6 have the shortest relatively straight runners, they are almost always the leanest cylinders in the engine by far. Not only that but the intake runners in the head aren’t all created equal, It’s 2&2 alike pairs. So individual cylinder trimming in the fuel mapping is critical.
360BD1F0-B391-491C-96CE-7B6ACFF74985.jpeg
 

green787

Well-Known Member
Joined
Jan 2, 2005
Posts
10,926
RDC Crypto
2,698
Location
Southern, CA.
Website
realsound.us
i was told most important is each intake length is the same& same volume, i got that after i asked an engine dood why old can am era engines had different length& velocity stack dimensions, it was thought to spread out the tork band, but it hurt horsepower , oh well, its an ongoing r&d that costs lottsa cash👍(imagine going 240 mph in an ALUMINUM gas tank with a800-1200 hp engine bolted to the back with just a 1-1/2" thin wall 'roll hoop'...
You can't touch a MacKay fuel injection system for under $5000.00....... Every McLaren builder wants that look under the rear window.....

ad_12_sb.jpg
 

scottm

Well-Known Member
Joined
Feb 7, 2005
Posts
1,902
RDC Crypto
601
Location
scottsdale AZ
Website
www.cemaz.com
Guessing an older 2 valve mc engine, like an XR200 or a yamaha TT?
 

Slippery P

Well-Known Member
Joined
Dec 8, 2007
Posts
2,814
RDC Crypto
3,282
Location
Valley Center CA.

partybarge_pilot

Well-Known Member
Joined
Feb 19, 2002
Posts
6,787
RDC Crypto
1,623
Location
Easton, KS
TTR125. It was for a buddy, don't think I want to do that agian. Put the BBR cam in it. They do not offer springs for it as, "they don't need them". Well, both the motors he has have bent intakes soooooo. They do offer a new CDI box with a higher rev limit so I'm sure that helps...... Also took .020 off the head per their recommendation....... and there is no way to degree the cam......
 

michael.gonzalez

Well-Known Member
Joined
Mar 13, 2018
Posts
4,849
RDC Crypto
1,815
Location
Camarillo, CA
Website
www.facebook.com
TTR125. It was for a buddy, don't think I want to do that agian. Put the BBR cam in it. They do not offer springs for it as, "they don't need them". Well, both the motors he has have bent intakes soooooo. They do offer a new CDI box with a higher rev limit so I'm sure that helps...... Also took .020 off the head per their recommendation....... and there is no way to degree the cam......
McMaster some baller springs. Dual spring it while you're at it! Lol.

I know YFZ450's did a 'YZF mod' where they put one of the cams fwd or reverse one cam gear cog.




Does anybody have experience porting a 2-stroke? Just curious how differently that goes.
 

green787

Well-Known Member
Joined
Jan 2, 2005
Posts
10,926
RDC Crypto
2,698
Location
Southern, CA.
Website
realsound.us
McMaster some baller springs. Dual spring it while you're at it! Lol.

I know YFZ450's did a 'YZF mod' where they put one of the cams fwd or reverse one cam gear cog.




Does anybody have experience porting a 2-stroke? Just curious how differently that goes.

With a 2 stroke it's about raising and lowering the ports to the maximum performance.... almost like a camshaft.... how long are the ports open.... too far and you loose HP.....
 

partybarge_pilot

Well-Known Member
Joined
Feb 19, 2002
Posts
6,787
RDC Crypto
1,623
Location
Easton, KS
With a 2 stroke it's about raising and lowering the ports to the maximum performance.... almost like a camshaft.... how long are the ports open.... too far and you loose HP.....

There is a lot more to it than that, port shape/width are really dependent on ring ductility. Direction is also important to cylinder clearing without losing to much out the exhaust. Bigger ports need to be offset with reduced crankcase volume to keep the transfer velocities up. Then you get into squish band tuning and reed timing........
 

jon coleman

Well-Known Member
Joined
Jan 17, 2019
Posts
10,882
RDC Crypto
6,584
Location
sandiego
There is a lot more to it than that, port shape/width are really dependent on ring ductility. Direction is also important to cylinder clearing without losing to much out the exhaust. Bigger ports need to be offset with reduced crankcase volume to keep the transfer velocities up. Then you get into squish band tuning and reed timing........
power valve rate& timing, is important too, -de burr /edge chamfering ,take the sharp edges away on the ports, ESPECIALLY exhaust ports, ( ps ,long bed trucks are nice...
 

Attachments

  • 20211015_170447.jpg
    20211015_170447.jpg
    1.4 MB · Views: 0
Last edited:

Total Loss

Well-Known Member
Joined
Jun 5, 2006
Posts
1,103
RDC Crypto
560
Location
Prescott Valley, Az.
i was told most important is each intake length is the same& same volume, i got that after i asked an engine dood why old can am era engines had different length& velocity stack dimensions, it was thought to spread out the tork band, but it hurt horsepower , oh well, its an ongoing r&d that costs lottsa cash👍(imagine going 240 mph in an ALUMINUM gas tank with a800-1200 hp engine bolted to the back with just a 1-1/2" thin wall 'roll hoop'...
70s Can Am cars?
Just read Mark Donohues book. The Unfair Advantage...recommend it.
 
Top