Velocity porting vs. Oldschool porting

[fat_sac]

Heres a link for pics of my baby -

http://www.thegsresources.com/_forum/showthread.php?t=88207

I'm not really sure why for road racing aps itd really help(when you boucing off the limitter) but I suppose you gotta get up to the rev limiter some how, so I'd suppose it'd get there really fast:? . I'm not too sure.-darren

Nice bike man. It's cool you're taking intrest in the good stuff at such a young age. :-D

I'm not really sure why for road racing aps itd really help(when you boucing off the limitter) but I suppose you gotta get up to the rev limiter some how, so I'd suppose it'd get there really fast . I'm not too sure.-

I reread it and have come to a conclusion. I believe he's onto something, but for low end motors. He mentioned an R1 in there. I would think his technological opinion would be better suited for a Dodge Viper, not a sportbike. The thing I've always heard about high velocity runners is that they restrict flow on the top end. Where a road racing app would be more suited. I don't know though, maybe all the dude does is drag race?

[speedy400]

I'll snap some shots, I'm done working on the ports(physically reshaping for more flow) , now all I have to do is smooth everything out(about 4-6 hours with sand paper just getting everything sanded smooth again)... A little hint- sand the intake to about 140 grit, then leave it, and I like to sand the exhaust to about 400+- grit depending how important the project is. I have heard polishing to a mirror finish on the exhaust compareds to say 400 grit, will gain like... 1/4 of a hp... and takes hours to get it to that finish, so unless your a hardcore dragger, skip it.-darren

[speedy400]

intake-darren

[speedy400]

exhaust-darren

[speedy400]

intake from combustion chamber-darren

[BadBillyB]

Using epoxy on the intake ports is not really new. I was doing this back in the 80's on my GS1000...It works the best if you use the later model "big port" head. I raised the angle of the intake port so much that I cut into the lifter cavity. Then I made some custom aluminum spacers and J-B welded them into the lifter cavity just below the spring base. This method along with using epoxy on the floor allowed me to obtain a more direct shot down the back of the intake valve head. The whole idea is to turn the air/fuel as soon as possible before it reaches the back of the intake valve as it will then flow in a cone around the valve into the chamber. By raising the floor you can turn it earlier. You also must know that when the air/fuel makes the sharp turn around the short side radius that it flows better with a flat surface. So looking into the intake port from the carb side the port should go from round to flat (in the curve) and back to round. The added benefit is that by doing this you make the short side and the long side more equal in lenght which is very desirable......On the exhaust side you want to raise the roof of the port as far as you can without creating a "lip" when you put your gasket in place. Almost all of the exhaust flows at the top of the port. Same thing applys, make the floor on the short side turn as flat as possible, only removing material from the sides to get the shape. After using something similar to epoxy in the exhaust ports to get that D shape on the floor, I can clearly see where all the flow is as the high flow areas burn away the material I used. Same as the intake, shape goes round then flat and then round.....keeping velocities high. If you want to get good at porting heads or just want to do a real good job on your own head, gather every book and magazine article you can find about cylinder porting and read them. A. Graham Bell wrote a very good book on 4 stroke performance tuning many years ago that is a must have. Smokey Yunick also wrote some very good stuff.....I have in my old racing folder, secret (well not now) tips and diagrams on how to port a nascar head. Its a compilation of all the bits and pieces that you learn that make a great cylinder head.......My race heads just laying around in the garage, maybe I can take a pic or two to share..........BadbillyB

[BadBillyB]

Heres a couple of pics of my ports. Intake

Exhaust

[BadBillyB]

Notice in the pic of the exhaust port, you can see the material added to the floor. Flat around the corner, then right before the gasket, the fire has eaten away the added material right in the center of the floor. These ports have been filled with Manley A&B compound, not epoxy. It is a 2 part material and hardens within about 10 minutes. I made a ball of it before using it and after a 30 minuteb cure, I dropped it on the floor and it sounded and bounced like a big fat marble. Very hard stuff, but wont last long in an exhaust port.....Great for drag racing though......BadBillyB

[headsbikesmopars]

http://mototuneusa.com/homework.htm

Some good and useful info here too. Terry.

[BadBillyB]

That guy's website is weak. Theres a lot more to porting an intake than laying a wad of JB weld in there. IMO JB weld is way too runny and requires up to 12 hours of babysitting to keep it where you want it. I dont even like JB weld as it has always fallen below my expectations whenever I have used it for anything. If you are expecting good results from a port job, you must know way more than this guy tells you about making an intake port flow well. It starts at the carb boot and ends in the combustion chamber. Every part of the port is a player. The floor, the roof, the sides, the angle, the bowl, the valve seat etc....Manley A&B Epoxy is my choice. It cures fast, 1 hour, requires no babysitting and is easily shaped with your finger, with no drooling.....If you want to do a nice port job yourself, become a sponge, and read everything about porting that you can get your hands on. Been there, done that, and have the trophys, plaques and national record certificates to back it up. Now if I could only get my 28 year old carbs sorted out, I'll be on a roll.......BadBillyB

[nastyjones]

Stick to your guns BillyB. You seem to know what you're talking about. Where can I get this Manley A&B you talk about. I'm in Canada.
Would it last very long in a street motor?
Oh yeh, & more pictures would help too

Paul

[BadBillyB]

Where can I get this Manley A&B you talk about. I'm in Canada.
Would it last very long in a street motor?
Paul

Most of the big race shops carry it. It should last forever in a street motor if properly applied. Intake port only. I did a google search and found this place
http://www.dougherbert.com/abepoxy-p-11156.html

[headsbikesmopars]

I use A&B apoxy by Moroso. Using it for years. Have it in the heads of my race car. Good stuff. I let it set up over night. I use a cup of water when working it into the final shape. A wet finger tip keeps it from sticking. I use regular modeling clay to make changes to the ports while on the flow bench. When I find something the port likes I make it happen with the epoxy. Alot to be said for keeping the velocity as hi as you can. I think that is the point he was trying to make. Most head shops make them too large. I know that what we try to achieve in my shop is the most flow with the smallest port. Might want to give it a try if you havn't...might be surprised. Been doing heads for over 25 years, everything from Pro-Stock to Nascar. My heads have been around Daytona a few times too. As they say..'just the facts mam'.

[nines]

Rebuttal

BADBILLYB: You should listen to HEADSBIKESMOPARS, he really knows what he's talking about when it comes to head modification to squeeze out all the power in them. He's been doing this type of massaging for 25 yrs + If you knew his name you would know him immediately. He wants to remain anomous. His heads were on the winning car at the first race at california race track last year one of the military cars can't tell you the # you'd know rite off. Some of his customers have won championships in the pro stock circuit and the top fuel series as well. He still holds 2 (two) national records with his 72 Duster.

[headsbikesmopars]

Nines, I appreciate the kind remarks. True..I have some credits I am proud of. I am modest by nature and try not to take credit for the success that others have achieved thru thier hard work and dedication. True I have built some of the heads that have been on successful teams (NHRA and NASCAR and some of the independent racers as well). But as many well know..heads are an important factor in any engine combo, but not the ONLY thing. Many more factors involved. Thanks for the anonymity, I am just one of the guys. And my passion is motorcycles. And mostly Suzuki's. I am a new member to this board although I have visited it many times over the years. There are many good and knowledgeable people on this board and BadBillyB, is one of them. We are all in good company. Lead on guys.