4-stroke porting

[Need for Speed 2]

This brings me back to what I thought was a valid statement,Isnt easy to just turn up the boost to get a few more ponies, I cant think that yamaha left a bunch on the table for the die grinder. In theory all this porting sounds good but I am not buying it for what it takes. But would love to see some hard data from someone whos willing to dive in.

 

[Blue shadow]

With the meth injection on 660 ft racing ,would I get there faster with the stock pistons on 20 psi .Would I still be able to run 91 oct pump gas without any dito ?thanks

 

[HURRICANE]

GUY's,,,,,the meth injection rises the OCTANE of the charge.Depending on the amount of WATER in the meth and the volume of meth added will set the octane of the charge.It's not uncommon the have a charge with better then 120 octane. I have not been able to find the point of detonation using meth,and I have run alot of cylinder presure. I have not tryed ALL possible combinations though

 

[MOB]

http://www.ty4stroke.com/viewtopic.php?t=63367...continued discussions...

 

[aja636]

In reading all of this, I hope everyone on this site appreciates the knowledge these guys are giving out for free. This information and advice is worth a fortune.

I was going to crank up the boost a little on my sled this year and was on the fence about meth injection and was looking more into porting the same as every one else, but what one thinks and what the reality is always to different things.

Thanks to all for shedding light on this subject.

aj

 

[RXB-1]

I have had much success with a mild to mid level port and polish on everything from chain saws to dirt bikes. No sleds yet. Mostly just an enlarge of the port and a good polish, Not much if any at the cylinder wall on the two strokes. While the head is off and on the bench I have a hard time not working over the ports.
What do you consider a bad port / polish job? I always figured it was allot about air flow.

 

[TWIN TURBO]

This brings me back to what I thought was a valid statement,Isnt easy to just turn up the boost to get a few more ponies, I cant think that yamaha left a bunch on the table for the die grinder. In theory all this porting sounds good but I am not buying it for what it takes. But would love to see some hard data from someone whos willing to dive in.

I definitly agree with this, Yamaha builds 3 million small engines a year, not like they started yesterday. It's alot easier to loose power than gain from porting. Turbo's MAY bandaid a poor port job abit, and after you spend $1200.00 your not exactly in a hurry to say "It didn't do Much"
Just turn up the boost, if your at the end of the line with the components you have change them. I've personally cracked blocks at 500 HP with no porting, no meth, no tricks. Where are you going from here. Porting wont help me. Like someone said, "It's All About Cylinder Pressure"