High compression head
- Thread starter 1racer
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theshadowrider
Well-known member
Just don't hold the throttle for more than a few second on midrange though!
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theshadowrider
Well-known member
Not so much with this head just any of these sleds in general. I would put a fuel controller regardless if you are out of warranty and want to extend your engine life. I have egts and fuel controller and midrange is still lean and temps still will scare you if you hold it for more than a few seconds. This is a common problem and why dragons are dropping like flies IMO.
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1racer
Member
Wouldn't raising the compression theoretically richen since you are taking in less air in the cylinder and same amount of fuel? I talked to slp and they wouldn't say one way or the other on the fuel controller just wanted someone else's opinion or personal experience. I have ran slp heads on sleds in the past with great result.
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theshadowrider
Well-known member
I can't really say on the fuel mixture other than I "think" it will still be similar just higher compression. Whatever the reason polaris thought it would help reduce engine problems by recalling all the 800 cfi engines and putting the lower compression heads on them all with the 2010 update. I would still run a fuel controller because if it does effect the tuning it will only be slightly. These engine are really lean in the mid-range and rich on the top-end. If you are going to put the new head, it would money well spent to get a fuel controller and egts/air fuel.
Sorry, I just realized this the pro-ride section. I thought I was in the iq section. I have zero experience with the pro!
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theshadowrider
Well-known member
That's better than my 2008 dragon. It has 92 psi a side and that was with only 200 miles on the new top end. I did check the piston and cylinder and no scuffing and rings where fine. Part of it being so low may be the compression checker (harbor frieght). It runs great I was getting a baseline, new engine before the turbo.
What elevation are you at? I think SLP recommends nothing below 6K. I had a high compression head on my D8. Really woke it up! But...I had to go back to the original Polaris map because of the quick detonation of the revised map. you will likely have to run a couple gallons of race fuel, especially if you have ethanol fuel like we do here in Colorado. EGT's would be great insurance.
Putting on a head is not going to affect your fuel mapping. Simply put as it inceases the compression it increases the chance of detonation. The fuel combusting pre-maturely due to pressure and not the iginition system...The only thing you would need to do in this case is run a higher octane fuel to prevent the deto...
It won't effect fuel settings but detonation sensitivity is part of the map (and so are fuel settings). So when the new update came out for the D8's I did a high compression head that made that very sensitive detonation light come on. After I switched to the stock (what came with the sled) map, I experienced no detonation.
^^^^^ECHO...ECHo....ECho...Echo....echo.....^^^^^
cranking compression really isnt that big of a deal..its a number..what matters is running compression..which is greatly affected by port height, piston dome and head dome..just because its low at cranking speeds doesnt tell the whole story..the pro has more at cranking speeds due to the lowered port height(explaining the vastly improved bottom/mid range snap compared to the dragons...but..if you can raise the static compression without running out of octane..you will make more power...right up until you run into deto....the motor will also make more torque and be much snappier....
Maybe that info wasn't intended for you.
