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DTR Pipe Numbers???

the SLP and other exhausts must have fuel added to make more HP! Yes you may install a pipe from SLP or others without adding fuel, but it will be lean and lazy and no deto but it will be 13/1 14/1 or leaner, maybe no deto there, and run OK, but you can't make more HP without more fuel.

Amen to that!:face-icon-small-hap
 
And doesn't the ethanol plug add 5% more fuel than the non-ethanol plug? And costs a lot less than a PCV! ;-) Would seem like a no-brainer when used with a pipe and good non-ethanol premium!

Have FUN!

G MAN
 
I would like to know about this also. Has anyone and including DTR tried the ethanol plug and measured the air fuel ratios?
 
Not discounting Jim's work or anything but just for the record; raising (shimming) the cylinders (which raises the port timing), shaving the head, and altering the timing curve is an age-old speed shop trick that has been no two-stroke secret for longer than most of you have been alive! The drawback to doing this is that you'll lose some low end torque but the pipes can gain that back by higher sonic reflectance as can advancing the timing at the beginning of the curve. This isn't something Jim discovered, he's simply putting up the numbers by going down that path (and good luck with your warranty if you decide to take that path!).

Have FUN!

G MAN

If these so called tricks would have been tried on the Dragonn it would not have worked. The port timing was lowerwed on the Pro engine so they are just putting it back to what the Dragon was with a little extra. The timing on the Dragon was on the edge so that was also chnaged on the Pro. The mistery was that the Pro engine did not make the power the Dragon engine did. Polaris ran teh engine at less than optimum tuning to guarentee reliability ans it looks as though that has worked. The question is will it still be reliable if we tune it up. Personally I think so.
 
And doesn't the ethanol plug add 5% more fuel than the non-ethanol plug? And costs a lot less than a PCV! ;-) Would seem like a no-brainer when used with a pipe and good non-ethanol premium!

Have FUN!

G MAN

If I remember right, the timing is altered (retarded) with the ethanol plug.

Not discounting Jim's work or anything but just for the record; raising (shimming) the cylinders (which raises the port timing), shaving the head, and altering the timing curve is an age-old speed shop trick that has been no two-stroke secret for longer than most of you have been alive! The drawback to doing this is that you'll lose some low end torque but the pipes can gain that back by higher sonic reflectance as can advancing the timing at the beginning of the curve. This isn't something Jim discovered, he's simply putting up the numbers by going down that path (and good luck with your warranty if you decide to take that path!).

Have FUN!

G MAN

I'm not sure about everyone else, but I wasn't crediting Jim for some new innovation, but for the dyno work he has done experimenting with this concept.
 
If these so called tricks would have been tried on the Dragonn it would not have worked. The port timing was lowerwed on the Pro engine so they are just putting it back to what the Dragon was with a little extra. The timing on the Dragon was on the edge so that was also chnaged on the Pro. The mistery was that the Pro engine did not make the power the Dragon engine did. Polaris ran teh engine at less than optimum tuning to guarentee reliability ans it looks as though that has worked. The question is will it still be reliable if we tune it up. Personally I think so.

Good points and great discussion! Curt pointed out that raising the cylinders can cause a loss of support for the pistons which, IMHO, could be a major issue for this motor since it is considered a short stroker to begin with (at least that's what I read). I'd like to hear more input on this but less support = more piston rock and eventual slap leading to premature failure. I'd be more inclined to go with porting over shimming (poor man's porting) when it comes to mods that will void the warranty. I also have reservations about shaving the head versus a good aftermarket head with improved combustion efficiency thru better dome design and not by just raising compression.

Have FUN!

G
 
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If I remember right, the timing is altered (retarded) with the ethanol plug.

I'm not sure about everyone else, but I wasn't crediting Jim for some new innovation, but for the dyno work he has done experimenting with this concept.

I've heard it wasn't with the ethanol plug, just fuel; anyone know for sure? And yes, Jim certainly deserves credit for the dyno work and the gains he's found!

Cheers,

G
 
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I just bought a membership for DTR and tried to open the 800pro pipe shoot out but the file won't open ,I can open every other file except that one , has this happened to anyone else
 
I just bought a membership for DTR and tried to open the 800pro pipe shoot out but the file won't open ,I can open every other file except that one , has this happened to anyone else

yeah they're kinda acting up, had to try a couple of times. Could not open with Firefox, used Explorer and after a few tries it came up.

Looked like nothing happened for a while tho.

I'll stay true to the other buyers and Jim, wont post from the article.

But I will, for the sake of this little argument, point out that it said on brand X pipe "required extra mid and top end fuel added to match the higher airflow."

This does not necessarily mean they did not on the others, but when I read it it "looked one way" and I was simply wondering if I could get away with just the pipe and clutching for starters.

Yes, fuel + air = power! And if we assume the mapping and the A/F ratio is perfect then sure, need more fuel to make better use of the improved airflow.

Perfect mapping from poo? Any takers? Dragon owners maybe? :face-icon-small-win

Rant over!
 
I just bought a membership for DTR and tried to open the 800pro pipe shoot out but the file won't open ,I can open every other file except that one , has this happened to anyone else

Make sure pop-up blocker is turned off. Took me 3 times to open it up. I'm wondering why the stator wasn't turned instead of the timing key.
 
I would have to read it again to be sure but I believe they added fuel with all the pipes. I think he said they did a base run to get the A/F ratio to give them a base to add fuel with each pipe by adding fuel to closely match the A/F ration for the given additional air flow the pipes provided.

The Change in port timing with the compression adjusted via the head shaved didn't gain any power to speak of. Only after adding some timing advance did they gain any power. So is it the change in the port timing in conjunction with the ignition timing or is it just the ignition timing and the port timing isn't even a factor. That wasn't checked and I wish that it had been addressed.

Great right up and a lot of good information. Thanks Jim
 
I wish they would have had time to try timing on a stock motor. If increasing timing on stock engine got a couple HP, then put on the Aaen pipe? Mid 160's,
and best torque.
 
I just bought a membership for DTR and tried to open the 800pro pipe shoot out but the file won't open ,I can open every other file except that one , has this happened to anyone else

Hey.. If you have a membership.. and having trouble opening the files..

U NEED to Upgrade your ADOBE X Download it.. and it works fine



FYI!!!!!!!!!!!!!!!!!!!!
 
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