Belt comparison

[Studroes144]

This write up is from what I posted on the Facebook page earlier, it's comparing the 8jp, 8dn and gates carbon belt on my turbo viper. I just copied it and pasted it here, I refer some to the video I posted on Facebook too so don't get too confused by that, there's no video here. Speeds were all taken with a radar gun, at 106 mph on the viper speedo the radar gun read 107, so speedo is actually a touch low. "Good day of playing, basically wanted to use today to try 3 different belts: gates carbon (stock viper length), stock 8jp and the 8dn. The clutching responded the same to the 8jp and the 8dn, both turning 9,000 rpm. Holding the sled wot for the full 1/4 mile length of the field the 8jp went 101mph and 8dn went 103mph. Switched to the gates and right away it wouldn't pull the rpm that it was with the yamaha belts (a lot more grip) so went to doing the clutching on it. The gates gripped so hard that on a launch I could only get it to pull 8,000 rpm and then from there it would build up to 9,000+ and eventually hit rev limiter. I'm still running the 50/46 helix from my D&D clutch kit which isn't good at all for a turbo sled. Going to use the stock helix next week and hopefully that will allow it to pull rpm right off the line. Anyways this video is when I had the gates belt on, I'm only running 1000' in this video, I have the 1000' marked and that's where we're holding the radar gun. 107 mph and you can hear in the video it's still hitting the rev limiter. Made one more adjustment after this and got 108 in the same distance just didn't get it recorded. Once I get the right helix combo the speeds will only get better, but for now doing a real world test the gates belt is 7 mph faster than the 8jp and 5 mph faster than the 8dn. Didn't get to check belt or clutch temps with the heat temp gun but after 2-3 runs the two yamaha belts had the clutches running very hot and you couldn't hang on to the belt. With the gates belt the clutches were very noticeably cooler and you could hold right on to the belt no problem. So far the gates belt has far better performance and efficiency and the cheaper version can be bought for the same price as a new 8dn. All testing was done with 5 pounds of boost and running rich afr numbers. The belt test is what we were after. Hope it's helpful!" Also want to note that as the day went on the conditions got a bit poorer, by the time I got the gates belt dialed in the dirt was all chewed up and ground wasn't frozen at all so there was a bit more drag when I ran the gates compared to the 2 yamaha belts.

 

[TD Max]

Belt part number?

I defer to the clutching experts for comment, but it seems strange that the clutching would need a major redo to work with a different belt. Is the belt gripping that much better or somehow just causing overshift?

I've heard they were good and want to believe, but something does not quite add up.

 

[Studroes144]

Belt part number?

I defer to the clutching experts for comment, but it seems strange that the clutching would need a major redo to work with a different belt. Is the belt gripping that much better or somehow just causing overshift?

I've heard they were good and want to believe, but something does not quite add up.

Will get the part # tomorrow. The gates belt grips noticeably harder. The fact that I was using the yamaha belts which both revved up good right away and then switched to the gates and made no clutch changes right there shows a big difference. And like I said, all speeds were taken with a radar gun, once rpm was dialed in better for top speed the gates ran faster mph in a shorter distance. For the 8dn I didn't need to make any adjustments to the secondary as far as belt heights, I put it only and it rides just a bit above the top of the sheaves as if it were the actual belt that's meant for it.

 

[Studroes144]

I'm by no means a clutching expert, all I did today was simply adjust my weights to run proper rpm for the different belts, those were the only changes made. Don't want this to turn into a clutching post, just want to share info on the belts. Since the only changes I made were taking weight out of the primary it just gives a better real world example. For the record no huge changes were made when I say taking weight out of the primary. To run the gates belt at proper rpm on a long wot run all I did was remove 2.6 grams of weight from each weight from where they were previously set for the 8jp and 8dn.

 

[TD Max]

Not doubting, just trying to understand. If it's as good as it seems, it's surprising that the clutching gurus haven't picked up on it yet.

 

[Studroes144]

The gates belts weren't out until late last season, by then they all had clutch kits out that were based on the 8jp or 8dn belt.

 

[drumz11]

Did you take any measurements of the gates belt vs the Yamaha belts? They can be a bit off from the advertised specs.

 

[Studroes144]

No measurements. But as far as just putting them on and running them, all three belts are within a 1/16 of an inch of each other as far as how high they ride in the secondary.

 

[cannondale27]

My gates is way lower in secondary than 8dn. You should be adjusting deflection when going from one belt to other.

 

[Studroes144]

My gates belts sits flush if not just a little whisker above the secondary, the 8jp and 8dn I used both sat just above the secondary, The very slight difference I don't think will be making much if any affect. The 8dn is only riding 1/16" higher

 

[TD Max]

So can I boil it down to make it easier to get to the facts?

8jp went 101 mph in 1/4 mile
8dn went 103 mph in 1/4 mile

Same clutching to 9000 RPM worked with both belts


Gates 40C4313 belt change resulted in 1000 RPM loss/drop and required 2.6 grams to be removed from each weight

Gates belt then ran 107 then 108mph in 1000’

No changes made in belt deflection required when changing belts.


Sounds like you'll be needing some overdrive added to the primary

 

[stingray719]

Belts have different gripping compounds. The only true test is to take time and test each belt in the correct setup for that belt. Let me give an example, if you do not have enough gripping force a soft belt makes you go faster....but not as fast as the original belt with the correct gripping force. Remember Barry has a custom clutch, taking his belt results and transferring them to a stock clutch will not be the same....maybe better maybe worse but not the same. That is why all our clutch testing was done with Yamaha parts for a control factor.

 

[Studroes144]

Once I get the stock helix back in I'll do the same thing again to see what the outcome is. As for the weights I'm using they are the same profile as the stock 8gl weights except they are heavier and easier to adjust, so realistically once I get the stock helix back in it'll be basically the same as stock with the exception of weights that adjust different. I personally don't care which belt is faster, whichever one is fastest, quickest and doesn't blow the track out on a launch is the one I'll be going with, and I'll share everything that I notice when doing the changing of belts. The biggest factor right now is the helix I have is shifting too quick for this setup, the gates belt grips more so it pulls rpm down more, yamaha belts don't grip as much therefore there isn't as much rpm change on a launch but the yamaha belts run hotter because of that slippage, yes I can adjust to make yamaha belts work better, but the gates belt clutch setup was much farther off than what the yamaha belts liked and it posted 5mph faster in 300 less feet.

 

[stingray719]

Try a green/white /green with a 4mm shim and see if you get any slippage with 8DN.

 

[Studroes144]

That spring will give less belt pressure than what I'm using now