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U4.2 fuel

4742 Views 24 Replies 11 Participants Last post by  rawyfz, 
Bigdaddy660R
Who runs this fuel ??

I just tuned my 720 rappy motor today switching from VP 110 to U4.2 All I can say is WOW.

Good HP gains, the Gain I was most impressed with was the torque number...........

I'd like to hear what you have to say about this fuel........
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Kawiking
whats the diff between it and reg. U4 ?

because U4 is just a oxygenated fuel ... i dont think its a high octane fuel .
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renoyfzfan
you dont need as high of octane nunmber when it comes to oxy fuel what i have notice the lower the rating the higher the oxygen in the fuel mr 11 which is what i run is 90octane and my 16-1 build i have no problems
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Bigdaddy660R
I was a bit worried about detonation also. U4.2 is rated at 102 octane, So far so good, we made 18 pulls on the dyno without it missing a beat.
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Kawiking
cool.... i ran u4 / 93 octane in my kfx400 when it was stuck... ran damn good !!! just had to jet it up. but damn did that u4 make my garage stink .

http://forums.atvdragracers.com/index.php?showtopic=2794
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MHEIDE
Glad ya got'r dialed in Jim, RoosterBuilt's "tune's" are the best in the Pacific Northwest. I've had no problems running U4.2, but was a little concerned with all the residue in the throttlebody and intake port's before it went to RF.
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Bigdaddy660R
QUOTE (SUB454 @ Feb 1 2009, 04:17 AM) index.php?act=findpost&pid=28639Glad ya got'r dialed in Jim, RoosterBuilt's "tune's" are the best in the Pacific Northwest. I've had no problems running U4.2, but was a little concerned with all the residue in the throttlebody and intake port's before it went to RF.

Same here.........

I'm emptying the tank after every use and purging with pump premium (i know what a pain) so I can avoid the residue issue........
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JP374
QUOTE (Bigdaddy660R @ Jan 31 2009, 09:52 PM) index.php?act=findpost&pid=28604Who runs this fuel ??

I just tuned my 720 rappy motor today switching from VP 110 to U4.2 All I can say is WOW.

Good HP gains, the Gain I was most impressed with was the torque number...........

I'd like to hear what you have to say about this fuel........


Like what kind of gains???? H.P and TQ
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Bigdaddy660R
QUOTE (JP400R @ Feb 12 2009, 03:41 PM) index.php?act=findpost&pid=30239Like what kind of gains???? H.P and TQ

I will say this much, The numbers put a BIG smile on my face........

I'm not going to post dyno numbers. For whatever reason I've seen more Internet wars when someone posts up numbers or dyno sheets...........

Not trying to be a jerk just want to be real and run it at my local hill or track and let the quad and rider do the talking...........
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JP374
QUOTE (Bigdaddy660R @ Feb 12 2009, 09:37 PM) index.php?act=findpost&pid=30263I will say this much, The numbers put a BIG smile on my face........

I'm not going to post dyno numbers. For whatever reason I've seen more Internet wars when someone posts up numbers or dyno sheets...........

Not trying to be a jerk just want to be real and run it at my local hill or track and let the quad and rider do the talking...........
VP claims gains of 2hp and 4 ft lbs to be significate just wondering if maybe when you got your gains if it wasnt from gettin it dialed in all together or if it was in just switching fuels thats all???
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Bigdaddy660R
QUOTE (JP400R @ Feb 12 2009, 06:46 PM) index.php?act=findpost&pid=30268VP claims gains of 2hp and 4 ft lbs to be significate just wondering if maybe when you got your gains if it wasnt from gettin it dialed in all together or if it was in just switching fuels thats all???
It was real close (Dialed in) on the VP 110. If that's what VP says, My HP gains did better than that. The torque gains did WAY better than that.

Also I used the same Dyno for tuning both fuels.........
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JP374
good deal
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P
QUOTE (JP400R @ Feb 13 2009, 06:51 AM) index.php?act=findpost&pid=30345good deal


Big D I felt the same thing from U4.2 with my [censored] dyno. I switched from vp110 to U4.2 and was sold a few months ageo. But it did grow some hair in the head even with the flush but I figure you hafto give up something to get something
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morse250r
i saw it on a dyno with a 450r built and it was really only 1-2 hp differance not much for the extra$ but hey every little bit helps
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P
QUOTE (morse250r @ Feb 13 2009, 01:47 PM) index.php?act=findpost&pid=30381i saw it on a dyno with a 450r built and it was really only 1-2 hp differance not much for the extra$ but hey every little bit helps


It helped me alot partly because I ride at 6000ft above sea leval.
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P
QUOTE (PIPELAYER @ Feb 13 2009, 01:56 PM) index.php?act=findpost&pid=30384It helped me alot partly because I ride at 6000ft above sea leval.


Big D is your raptor faster then your ds650? or did this make it a good race?
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Bigdaddy660R
QUOTE (PIPELAYER @ Feb 13 2009, 01:57 PM) index.php?act=findpost&pid=30385Big D is your raptor faster then your ds650? or did this make it a good race?
Na the DS was and always will be faster than the Rappy. When David and I tuned it right b-4 Dunefest Dave had sub454 797 on his dyno finishing up on it. We took his quad off and strapped the DS down and went to work dialing it in. The part I found above and beyond was you could hear the DS rev allot faster than the 797 did. Eric knows how to make these DS motors sing AND it did it all the way up to 10500 RPM.........

Bottom line (for me) the DS rotax head with intake & exhaust cams on valves and the magic Eric did to these heads & cams makes them far superior to the 660 based raptor head. single cam, rocker arms ect.

But I'm sure others disagree with that.
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P
QUOTE (Bigdaddy660R @ Feb 13 2009, 04:45 PM) index.php?act=findpost&pid=30397Na the DS was and always will be faster than the Rappy. When David and I tuned it right b-4 Dunefest Dave had sub454 797 on his dyno finishing up on it. We took his quad off and strapped the DS down and went to work dialing it in. The part I found above and beyond was you could hear the DS rev allot faster than the 797 did. Eric knows how to make these DS motors sing AND it did it all the way up to 10500 RPM.........

Bottom line (for me) the DS rotax head with intake & exhaust cams on valves and the magic Eric did to these heads & cams makes them far superior to the 660 based raptor head. single cam, rocker arms ect.

But I'm sure others disagree with that.

I found the same thing with Eric's cams making power over 10,000 RPM . so is that the reason sub454 dug back in to it
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S
I have used both 4.2 and mr11 and now i am using pro v1 I think the motor revs a little quicker and I am able to get it cheaper than mr11.
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rawyfz
QUOTE (Bigdaddy660R @ Jan 31 2009, 09:52 PM) index.php?act=findpost&pid=28604Who runs this fuel ??

I just tuned my 720 rappy motor today switching from VP 110 to U4.2 All I can say is WOW.

Good HP gains, the Gain I was most impressed with was the torque number...........

I'd like to hear what you have to say about this fuel........

I ran U4 years ago and didnt like the way it gummed up my carb. On vp website they claim U4.2 doesnt do that has anyone ran it and seen for themselves? If so I am going back to it cause Im tired of purging and all that crap with U4 or alcohol. Been back on regular race fuel here lately.
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