Anyone find that with the 13.6-1 pa head that the peak rpm is lower??

[lightening800]

I found my sled wants to run at approx 8 g now. I tried various other things to gt the rpm up but it's the same verdict, lighter weights yields no gain either, I ran into this before and it was no big deal but just had to throw weight at it till I could not pull it anyone. 64 gm weight still pulls 8 g and so does 62 gm weights, it obviously pulls harder with 64 weights. High compression heads usually yield lower rpm, but was just wondering if I'm the only one..

 

[ghost rider]

Head

My bros sled does the same thing 8000 rpm with helix change, tried gearing down, and different weights and same result. Sled runs great just won't pull over 8000. Maybe it's a bad digital gauge reading 200 plus rpm's off? Also put one on my dads and his pulls 8150 all day long? As long as it doesn't fade I guess no need to change?

 

[06IQRMK]

PA Head

Brad (1200psi) from power addictions had posted the dyno results from using this setup. Peak power was right around 8050 with the 13.6 head at around 5500ft. Looks like there was some impressive lower rpm and midrange gains over stock too. (to the tune of aroud 14hp at 5500 rpm over stock and around 4.5 peak) I see that the dyno chart has dissappeared or i wouldve posted a link for it. You might get ahold of him if you want to get a look at it I bet he removed it from the post.

 

[Bossman]

13.6 head versus rpms

The 13.6 head is absorbing heat that normally heats the pipe. Less pipe heat = less exhaust gas speed. That in turn changes (slows down) the moment at which the reverse wave in the pipe reaches the exhaust port to stuff the escaping unburned air/ fuel mix back in the cylinder. You could try removing the pipe's clamshells, having the pipe ceramic coated and reinstalling the clamshells, provided the engine has enough cooling and good enough head seal to stand the additional pressure. That will raise your operating RPM and hopefully give you even more gains.

 

[1200psi]

Brad (1200psi) from power addictions had posted the dyno results from using this setup. Peak power was right around 8050 with the 13.6 head at around 5500ft. Looks like there was some impressive lower rpm and midrange gains over stock too. (to the tune of aroud 14hp at 5500 rpm over stock and around 4.5 peak) I see that the dyno chart has dissappeared or i wouldve posted a link for it. You might get ahold of him if you want to get a look at it I bet he removed it from the post.

Here is the dyno results we have. I didn't remove them unless a moderator removed them.


http://www.cpiracing.com/store/index.php?act=viewProd&productId=174

 

[F-Bomb]

Yes your sled will pull both weights exactly the same because your gain is through engagement to mid range. The top end at 7700-8050 is almost the same as stock. A couple dyno HP does not equal any weight pulling power and is mostly negated by setups. The dyno doesn't show you how much resistance factors like it does in the field or if you had a track dyno setup. JUST ANOTHER reason why guys should run the trimmed track. I get another gram to sometimes two over a non trimmed track at 7950 and the results on the field are plus 4 mph IE TOP END is even better. Stock tracks with this setup essentially act just like the stock head.

The real gain on this head is engagement to mid pull for you guys that run the non trimmed tracks. (it's conclusive that it is tip weight as every 1/2lbs added or subtracted from your track equals 1 gram or 100- 150 RPM)

If the poster would test his sled versus a consistent sample sled he'll find out that he gains 2 to 4 lengths consistently with 64 grams at 7950 versus 62 grams at 7950 - 8050. IT HAS NOTHING TO DO WITH PIPE SCAVENGE! DON"T MESS WITH YOUR PIPE CLAM SHELL! This setup is TUNED to operate at it's peak at 7950. Changing the tune of the pipe does nothing but start you over trying to find a high performance combo of clutch to transmission of power. This is the exact reason why guys can't find much performance in changing to an aftermarket pipe with the Polaris system.

Any doubts LETS RACE FOR MONEY

 

[dragonfire]

clutching with PA head

Yes your sled will pull both weights exactly the same because your gain is through engagement to mid range. The top end at 7700-8050 is almost the same as stock. A couple dyno HP does not equal any weight pulling power and is mostly negated by setups. The dyno doesn't show you how much resistance factors like it does in the field or if you had a track dyno setup. JUST ANOTHER reason why guys should run the trimmed track. I get another gram to sometimes two over a non trimmed track at 7950 and the results on the field are plus 4 mph IE TOP END is even better. Stock tracks with this setup essentially act just like the stock head.

The real gain on this head is engagement to mid pull for you guys that run the non trimmed tracks. (it's conclusive that it is tip weight as every 1/2lbs added or subtracted from your track equals 1 gram or 100- 150 RPM)

If the poster would test his sled versus a consistent sample sled he'll find out that he gains 2 to 4 lengths consistently with 64 grams at 7950 versus 62 grams at 7950 - 8050. IT HAS NOTHING TO DO WITH PIPE SCAVENGE! DON"T MESS WITH YOUR PIPE CLAM SHELL! This setup is TUNED to operate at it's peak at 7950. Changing the tune of the pipe does nothing but start you over trying to find a high performance combo of clutch to transmission of power. This is the exact reason why guys can't find much performance in changing to an aftermarket pipe with the Polaris system.

Any doubts LETS RACE FOR MONEY

Rob great post, so with what you are saying about the more power in midrange,the sled would maybe benefit from a little steeper intial angle helix out to about .46 or with Dalton weights, put alot more weight towards the heel to capitalize on the harder hit at engagement and midrange.Also totally agree with your analogy about clutching with the famous F-Bomb track mod which I am a big fan of.

 

[F-Bomb]

The real value of a dyno is to see what the engine package can do. It's super easy to look at the event and get half again closer to an ideal transmission package without having to spend so much time, energy, and money chasing transmission.

Yes I have absolutely concluded that you need a steeper than stock helix initially as the sled amps up through the power band. The Carls clutch kit favors a different weight than the 10 profile and they pull or load better in the midrange where you can use it. I have not tested any other weights other than stock and the Belly Busters. (mostly because I think that I have perfect clutching) You take advantage of this increased ability to handle load with a better clutch kit. You can look right at the dyno and see places that it will handle more load and that is super cool. Tie this in with what we know from field testing (which pretty much verifies what I've thought since we did our field testing prior to ever seeing the dyno reports) and it's pretty simple stuff.

I'm hesitant to add much more initial hammer to the setup which might be good for drag racing but could be a handicap in the deep snow. I want all around outstanding performance from the drag strip to the biggest hill my sled can climb. (the funny thing is most of what I really do and enjoy is simply free riding or boondocking and my video shows it to almost always be in and out midrange...I HAVE NO COMPLAINTS HERE EITHER) When you can pack the skis and kick butt drag racing right at 7950-8050 and then take the very same thing up a big long deep snow pull and have it set at 7950 the entire climb without any fade (excess heat) you are there. GO RIDE

Interestingly guys that are looking for 8200 and up thinking their sleds are running better on the PRO with stock porting pipe timing ect ect are going to be my victims in the money race! Flat or uphill it doesn't seem to matter.

 

[Montana powderhound]

Rob ,I took your advice on my brand new 12 163 head and clutching . Have not done the track yet but plan to. rode it for the first time monday and loved it other then the lock collar on the drive clutch started rattleing right out of the truck. piss poor polaris quality control. no locktight! My question to you is your weights . I have the kit per chris with 60s and about 7000 ft I jumped on the throttle on the trail and it det coded instantly I was just wondering if I need a little more weight as all day I bounced between 7950 and 8200.

 

[F-Bomb]

At 7000 feet mine pulls 64's! You need 62's if you ride 8000-11000 or what we consider the high altitude application. Especially when you trim it. You may need to trim the weight to 61 but I don't think 60's will be near the setup that 62's are for your app.

HERE IS THE AVERAGE CHART FOR THIS APPLICATION ON THE CARL'S CLUTCH KIT THAT I TESTED 13.6 head domes
4000-8000 64 grams (requires 93.5 octane net 4000 - 5500 91 oct 5500 up)
8000-1100 62 grams (91 oct did not test off to see if you can drop to 87 but I think you probably can at super high elevation apps)

This is all tested on a 155 but reports from other testers says that a 163 costs you right about 1 gram on average.

Some guys will find that they are in between the increments...especially trimmed the track applications. For example 63 grams is perfect at 8000ft for me but on average for our high alt apps we end up going higher and so I run 62's there. If you consistently get in an area you may want to fine tune. The secret is the most possible weight you can pull and get 7950. Once again every sled has slightly different requirements from track and over all setup. Rider weight didn't seem to be that big of a factor. A 170 lbs guy netted almost the same RPM's climbing and drag racing as a 240 lbs guy. (actually about 40 less r's on average and that wasn't enough to fine tune with the stuff we have in)

 

[Montana powderhound]

Thanks Rob and Brad for everything ,I will talk to Chris, by the way he tried reeeeeal hard to sell me his package deal with slp head ! I told him no , So far I love the way this thing pulls but still not enough snow to open her up.