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Top Speed AND The Yamaha Apex.... Whats the dreameter sayin?

I believe it makes a compression ratio of 12:1 not 13:1, And even with that I run a mix of 116 octane and premium, but can run just premium fine.
 

Where did you get your nitrous kit? That sounds interesting, not for my daily riding for maybe a short drag race.
 
Just FYI, J&E shows 13:1 comp in their piston specs.
Would hope it would run deto free on pump gas, you wouldn't be able to venture very far from home if it didn't.
BTW is yours stk bore, or 1mm or 2mm over?
 
standard bore
 
I believe the builder put a head shim to lower compression to 12:1
 
I was told to safely run pump gas to run 12.5:1 ratio or lower. I want a fast sled, but also reliable. Sure I could turbo the crap out of it and leave my connecting rods on the trail, but I put on thousands of miles a year and want to continue to do that. There's a balance there somewhere, I believe I am on the edge but just looking over it.
 
So how many miles currently on those JE Pistons/rings? How's oil consumption?
 
About 600 miles on them, Don't notice an issue with oil consumption. You know something I don't about this setup? Do they usually eat oil? I haven't had an issue yet..........
 
Yamatuner said:
Well everybody is different, but on my 07 Apex, I put high compression pistons, excell header, Hauck silencer, ram air, power commander 5 with custom tune, added 4th wheel kit to skid, added extra bogeys, dupont slides, anti-ratchet drivers, custom clutches primary and secondary, high speed gearing. Top end bearings. All things put together for less drag, more top end. I have yet to have a naturally aspirated sled to come even close on take off or top end. Haven't ran against the newest 800 or bigger two strokes, but I am confident that on the top I can pull away. I kill every sled I have ran against on the top. Raced a ski-doo 1000 2 stroke and walked away from the start and pulled far away on top, not saying I will beat every 1000, but that one added a notch to the belt. :) My mods are for 06-12 Apex. I have 187 hp at 11,000 RPM on track dyno. Only problem I have is this sled is a big heavy pig. I am awaiting yamaha to grow up and throw the Apex engine in the Viper/cat pro-cross chassis. Soon as that is done I will be buying one. Anyone who has driven an Apex has plenty of respect for the horsepower and torque, not so much the weight or handling. I know my sled is not the best sled, or fastest sled out there, but it is considerably faster than anybody I have rode with. I am sure in the trails a well set up 600 could give me a run, but in a drag race not a chance! And its reliable....... over 4500 miles last year, and 700 plus and counting this year without an issue.
Click to expand...

So high comp pistons, header, exhaust, ram air lid and pcV gave you 187hp? Say the exhaust ram air and pcv gave you a 10 hp increase, your saying the high comp pistons gave another 27hp on top of that? I find that hard to believe due to a ported head suppose to make 170HP with those mods and a stroker is suppose to make 200HP. Elaborate if you can, not trying to call you a liar, I know you said estimated 187HP.
 
Sold the sled over a year ago or I could give you the info I had with it. I have a 15 viper turbo now that is a great improvement. Miss the sound and top end pull of the Apex.....
 
I don't want to rain on anyone's parade but, there is NO WAY that an apex is makin that kinda hp without a power adder. My 06 has all the mods listed in my sig including 20 thou off the head for more compression. Tuned for max hp it recently made 162.5 at Jim's C&H Dyno (aka dynotech). As measured at the pto. The dyno would have to be EXTREMELY generous to read higher than what I recorded.

I should add that I'm referring to a stock displacement engine NOT a big bore or stroker.
 
Last edited:
would a good clutch kit not do the same? not change the top end but quicker acceleration?
 
justin gallant said:
would a good clutch kit not do the same? not change the top end but quicker acceleration?
Click to expand...
Clutching can affect both top-end and acceleration. But has absolutely nothing to do with making more HP.
Transfering HP yes, making HP no.
 
Your crank horsepower would definitely be more accurate than the track hp my old apex was tested at. Variations like temp sensor for dyno can change hp readings. I've had two apexs and a vector before going to my Viper and Sidewinder. The Sidewinder is easy hp where my Viper has taken a lot of tuning time. The Sidewinder has the 275 tune in it and it's faster on top end than the Viper but slower out of the hole. Using stock clutching on Sidewinder also. Gonna turn up to 16psi on the Viper like the Sidewinder is set at and run some test this weekend for comparison.
 
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