Question for those who have experience on dyno's (or have been dyno'd)

[r00st]

Alright so I was dyno'd with my 6 ply Razr's on ITP Baja wheels (not sure on the exact weight, but obviously heavier than stock and much heavier than a dedicated street/dyno tire).

Has anyone dyno'd the same bike ,same day with dyno tires (some sort of slick/street tire be it american racers, hoosiers, trailer tires etc) and then with some dirt tires? (be it stock, or razrs or what have you)?

I am curious the HP percentage difference.... Is it true that rotating mass has Less affect on Torque reading than it does HP? I read/heard that somewhere awhile back so I am curious if dyno'ing on my razrs is affecting both HP&TQ or just HP. I know that if the tires slip at all on the dyno it will really screw up the TQ but I am pretty sure I was not spinning so I dont think that is the case.

Any info is appreciated

[Colorado700R]

was looking up some info for you and stumbled upon this, a good read for all you Dyno racers

http://www.popularhotrodding.com/features/0612phr_dyno_accuracy_testing/index.html

[VelociRaptor]

Back when bamaquad was still stock we did that test, almost exactly 3hp difference on a stocker.

[r00st]

So needless to say, the percentage would be a constant change. So if a stocker put down say 38hp and then 41 with dyno tires that would be a ~7.8% difference.

So on a build that put down 55hp (mine) with dyno tires I could have achieved ~59.3 hp.

But...that was for whatever dyno tires they were (unknown) vs stock tires (known). So... to be actual we would need the weight of my tires (ITP baja wheel with Razr 6 ply tire) as well as the weight of that dyno tire. Since stock wheels/tires are pretty lightweight I would guess I am another at least 4 lbs per tire/wheel over the stockers. So this would increase the above percent quite significantly.

Granted I am bench racing which I hate when people do but im trying to justify my low numbers.

Two other factors were my build was having an oil consumption issue (need different rings..total seal = fail). So im sure there is a slight power loss there. Plus I had my ignition programmed with custom curves and did not play around with those at all (not even sure which curve its set on).

And to top it all off..even if I were to go back with some lightweight Hoosier slicks on .125 blue labels, WITH good rings, on the right ignition curve I would probably put down much better numbers. The problem with that...this build does not feel all that fast at all. To me it feels like about another 3-4 hp over the Big 3.

Barker duals
+3 KDS TB
KDS inline Evac Valve
Custom intake (stock tube, with FUEL ATV adaptor with HUGE No Toil filter on it)
+1 valve'd Barker CNC head
Beehive springs with RJ Cam
11:1 Diamond Piston
DL custom programmed Dynatek ignition


...And colorado700, just read that article and it was very informative! I guess my reason for posting this is to more or less realize my build FEELS weak and not just LOOKS weak on paper...lol.

[Pldbryan]

What altitude is this at??

Also, was the bike jus dynoed or was it tuned on the dyno?
Is it running a map that was given to you from a very similar build or was it tuned by your dyno guy during the dyno session?

[r00st]

900 ft elevation.

We were 1.5 hours into the dyno (actually a little more but he was taking his time and explaining some of the software to me...really cool guy). He works for dynojet and travels nation wide teaching classes on how to tune the PCIII/PC5 so im pretty confident in his tuning skills!

Because of the oil loss & the fact I didnt have extra oil with me combined with the fact he was concerned about his o2 sensors with me burning oil means we quit early. He said we were about 60% through the tuning but it was considerably better than it was.

While it was tuned on the dyno the pulls he printed for me were the very first two runs we made after strapping it down. Considering my AFR was horribly lean in the midrange (and overall) I had to have been at least a few hp/tq up over the baseline pulls for the day.

[1badazz_700r]

My first advice would be ditch the diamond and get a cp. cause your for sure loosing power there and causing dyno issues from the smoke so your not getting a good tune. I just went down this road about 2 months ago with a diamond piston. the diamond is a nice piston however you will never get it to stop smoking until they come up with better rings. I had the diamond 12:5, it smoked from first start up till i pulled it out and gave it to troywcc to experiment with. and it was not smoking due to ring allignment cause he got the piston just the way it came outta my motor oil on top of the piston and all. As soon as i installed the cp everything was good again, no smoking and no oil usage the diamond does have 2 good good features #1 it will clear any bugs within a 2 mile radius and it works well to keep your papers from blowing off your desk Look what the fast guys are running CP pistons. as i stated earlier the diamond is a high quality piston,its the rings that are the problem

[EHSRACING]

actually most of the hp loss comes from tire slip on the drum. If you go to a dyno with razors or something like that its almost like peeing in the wind its really hard to get the accurate results that you can with a street style tire. It really effects it on quads over 50hp i have seen 6-9hp diff and almost 10mph off from stock reading on bike odometer on 60-70hp quads from tires which is pretty big number a stocker 450r or something you might only see 1-2hp change. The weight difference will also make some #changes but not as much as tread vs no tread. I would see maybe 2hp change on a big raptor when running a small american racer vs a heavier 20" duro top fighter

[Krandall]

Also.. I wouldn't base all your feeling into the numbers, was it Gunz That thought his bike wasn't all that much better after doing a bunhc of motor work? Then took it to a hill and did some drags with it against other raptors and was beating them by 10+ lengths 

[Kamakazi]

im running the kds piston with the total seal rings, there is ZERO smoke.  i am not using oil that i have seen at all. (havent put on alot of seat time yet).  i will be going to a dyno soon and will be runnin my bald stock tires

[Kenny]

So needless to say, the percentage would be a constant change. So if a stocker put down say 38hp and then 41 with dyno tires that would be a ~7.8% difference.

So on a build that put down 55hp (mine) with dyno tires I could have achieved ~59.3 hp.

But...that was for whatever dyno tires they were (unknown) vs stock tires (known). So... to be actual we would need the weight of my tires (ITP baja wheel with Razr 6 ply tire) as well as the weight of that dyno tire. Since stock wheels/tires are pretty lightweight I would guess I am another at least 4 lbs per tire/wheel over the stockers. So this would increase the above percent quite significantly.

Granted I am bench racing which I hate when people do but im trying to justify my low numbers.

Two other factors were my build was having an oil consumption issue (need different rings..total seal = fail). So im sure there is a slight power loss there. Plus I had my ignition programmed with custom curves and did not play around with those at all (not even sure which curve its set on).

And to top it all off..even if I were to go back with some lightweight Hoosier slicks on .125 blue labels, WITH good rings, on the right ignition curve I would probably put down much better numbers. The problem with that...this build does not feel all that fast at all. To me it feels like about another 3-4 hp over the Big 3.

Barker duals
+3 KDS TB
KDS inline Evac Valve
Custom intake (stock tube, with FUEL ATV adaptor with HUGE No Toil filter on it)
+1 valve'd Barker CNC head
Beehive springs with RJ Cam
11:1 Diamond Piston
DL custom programmed Dynatek ignition


...And colorado700, just read that article and it was very informative! I guess my reason for posting this is to more or less realize my build FEELS weak and not just LOOKS weak on paper...lol.

Let me know if you have Tim's piston or mine.......We'll get you the proper oil rings out. I am not real sure why this is going on. About 80% of my pistons are working perfectly....... Not sure if we had a factory defective oil ring or what. Total seal supplies many of the aftermarket piston companies. If you have a an aftermarket piston in your 700, chances are good they have rings supplied by Total Seal.

The low dyno numbers are mainly due to your tires, but it sounds like there is a LOT of power left in tuning. Obviously the oil isn't helping (it could easily be 2-3 hp down). I have a quad out there doing about 57hp with the same tires and the build probably does feel lazy until it gets traction. He does a pretty good job of cleaning up the competition at the track on a trail build It would be funny if the tires had a limit of like 57 hp and gave up like a clutch or something

[Diggs59]

My first advice would be ditch the diamond and get a cp. cause your for sure loosing power there and causing dyno issues from the smoke so your not getting a good tune. I just went down this road about 2 months ago with a diamond piston. the diamond is a nice piston however you will never get it to stop smoking until they come up with better rings. I had the diamond 12:5, it smoked from first start up till i pulled it out and gave it to troywcc to experiment with. and it was not smoking due to ring allignment cause he got the piston just the way it came outta my motor oil on top of the piston and all. As soon as i installed the cp everything was good again, no smoking and no oil usage the diamond does have 2 good good features #1 it will clear any bugs within a 2 mile radius and it works well to keep your papers from blowing off your desk Look what the fast guys are running CP pistons. as i stated earlier the diamond is a high quality piston,its the rings that are the problem

Hmmm, that's funny. I have the Diamond and I have about 40 hours on the build thus far and there is "ZERO" smoke and "ZERO" oil loss.

[r00st]

Ok thanks for all the info everyone.

The Piston came from Tim. I dont think I would even feel alright with myself selling this to somebody (which sucks cuz I paid 200 for it and it has less than 10 hours on it).

So is the problem the depth of the ring lands on the piston? Because obviously its not just the rings if people are using these rings on JE/CP/stock etc etc pistons without any problems!

So...what piston should I go with? The CP "Tech" 11.5:1, or a straight 12:1? Are the CP Shelf 12:1's TRUE compression? I know the 11.5:1 is. I thought I read "most" uncorrected compression pistons that stated they were 12:1 were usually around 11.2 or something?

I would really PREFER to run 93 octane (can get it at the pump) but if I can get some pretty good power without sacrificing longevity of the motor I will run 12/12.5 and just splash some race gas in (unless @ 900 I can run 12:1 safely on 93?)

Sorry for all the questions it just makes me sick after all this I have to pull the damn thing apart with only 10 hours on it! Not that its a lot of money to put the top end back together (gaskets) it just takes time which I dont have much of these days. Granted I think this time I can rebuild it in less than half the time since ive already done it.

Badazzraptor: When you pulled the diamond out, did it tear up your nickasil at all? I dont see why it would but im hoping all I need to do is drop in the new piston and prep the cylinder.

[1badazz_700r]

I have went to a racers edge cp piston. but yes kenny this was your diamond piston. I gave it troy to experiment with and according to him the rings were clocked good and they were gapped and installed on the piston by kenny.troy gave the piston to another guy and he cant get it to stop smoking either or at least the last time i talked to troy. i just want to make sure everyone understands that im not trying to talk shit about kenny or his piston,cause as i stated earlier i think the piston's quality is top notch. and kenny is a supper good guy to deal with and very helpful as you all know. I was just at the point where i didnt want to keep tearing my motor down to change rings and see if that was the problem, because kenny did offer to give me new rings to try. I was just stating the problem i had

[1badazz_700r]

it did not hurt my cylinder one bit. i pulled the cylinder and piston. Hit the cylinder with a scotch pad and brake cleaner and re-assembled