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dual helix vs track speed

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snobyrd

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Im trying to tune my spi pipe and im trying to find out what angle I need to change. My current setup has a 62/42 .40. Yesterday my sled pulled great all day until I did a steep and deep sidehill with lots of throttle chop, and got a det code. My target rpms are spot on for my spi pipe with 70 grm pol weights at wot but now im thinking I need to change one of the angles to either a 64 or 44. At track speeds in that 30 mph range when im chewing hard, what part of the helix am I in?
and how long of a duration do I need.
 

FriscoProx

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I've been running a BMP pipe on my 850 for about 400 miles in the same area Eric was testing the SPI pipe. Running the mid 2019 flash. I would expect these pipes to be very similar. I'm always looking for an excuse to mess with clutching, but I've changed the primary spring to almond and otherwise having good results with stock clutching when the clutches are working well. Check your primary clutch cover spring seat. Mine was was super tight and was binding primary springs, including breaking one. I had the cover cleaned up on a lathe and added a pair delrin primary washers and no more binding. I can't say for sure it was the whole cause, but I was getting some over rev during back shifting and that's better now.

If everything's working correctly, and you don't already have those other helixes to try, I'd lower the secondary spring final rate 10lb/100rpms or 20lb/200rpms before changing angles again.
 

live2beel

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You’ll probably start getting belt slip in the secondary if you go down much more with the high helix angles your running. It would be interesting to see if you didn’t touch any clutching and put your stock pipe back on. I have one of these pipes and have yet to put it on. Was hoping to hear from others that have ran it. Seems super finicky!! It’s making power, because that’s some decent clutching your throwing at it. You might have to go back to your old weights and load the belly up on them.
 

Sheetmetalfab

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I’m curious how it would do with a full progressive helix like the indy specialty “mountain 1” helix.

Pretty amazing how that thing creates belt clamp and keeps gaining trackspeed.

Either boosted or N/A.
 
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snobyrd

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Nov 27, 2007
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You’ll probably start getting belt slip in the secondary if you go down much more with the high helix angles your running. It would be interesting to see if you didn’t touch any clutching and put your stock pipe back on. I have one of these pipes and have yet to put it on. Was hoping to hear from others that have ran it. Seems super finicky!! It’s making power, because that’s some decent clutching your throwing at it. You might have to go back to your old weights and load the belly up on them.
I just rode 2 days , first with the mtx weights loaded to 75 grm had had no det codes that day and I did some real good pulls that day, sno was 2 foot fresh, yesterday I also did alot of 10-20 second pulls where I would sidehill than hook it hard and go up the slope and out off the whole day, I got one code.
I'm also running in non eth mode with 91 priem, so after that code I switched to eth mode but that was at the end of the day.
I feel that I'm real close to perfecting my clutching, but now I'm just throwing it out there , what subtle change should I make, do I create a bit more load via a steeper initial angle, do I increase the duration, do I increase the final angle?
Or do I go back to my mtx weights that are now loaded to 76 grms, one more gram than my first ride as mentioned above.
One thing to expect from my experience is, when the sled has been shut off for say, 15 mins , the sled runs crappy, give it a few mins to get that pipe warm and it's good to go.
What altitude altitude are you running?
 
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snobyrd

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Nov 27, 2007
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I’m curious how it would do with a full progressive helix like the indy specialty “mountain 1” helix.

Pretty amazing how that thing creates belt clamp and keeps gaining trackspeed.

Either boosted or N/A.
I was chatting with Geo tonight about a full progressive helix.
Spi wants me to buy thier clutch kit and be done with tuning but I feel alot of those mid Western speed shops haven't done any revalant testing in that 6000 foot area, it's either low alt or very high, and neither of it works here.
I spoke with a shop today in Alberta that's installing outlaw pipe kits, they said the recommended tuning from slp was way off and thier doing thier own clutching kits.
I had the same experience with bikeman a few yrs back, so now I'm skeptical on what these shops suggest for tuning.
I would love to think that a full progressive would be the answer, than you never get stuck in that transition area of the helix.
Perhaps I'll give Indy dan a call tomorrow.
 
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snobyrd

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Nov 27, 2007
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I've been running a BMP pipe on my 850 for about 400 miles in the same area Eric was testing the SPI pipe. Running the mid 2019 flash. I would expect these pipes to be very similar. I'm always looking for an excuse to mess with clutching, but I've changed the primary spring to almond and otherwise having good results with stock clutching when the clutches are working well. Check your primary clutch cover spring seat. Mine was was super tight and was binding primary springs, including breaking one. I had the cover cleaned up on a lathe and added a pair delrin primary washers and no more binding. I can't say for sure it was the whole cause, but I was getting some over rev during back shifting and that's better now.

If everything's working correctly, and you don't already have those other helixes to try, I'd lower the secondary spring final rate 10lb/100rpms or 20lb/200rpms before changing angles again.

I tried the stock clutching and it was a disaster, Erik also had the same results from stock clutching.
He's generally using a 60/40 with either a 36 or 46 length and I believe 64 grm pol weights.
Spi told me to start at 62 deg and perhaps go to 64 deg
Spi recommend a 160/260 spring , but I'm not a fan of that, I'm using the stk sec spring.
 
M
Sep 13, 2009
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sure glad youve had some time on the snow and are willing to find out whats working.... im planning on running a 62-42.46---58-42.36 helix, stock springs, derlin washers, and polaris weights..... only thing is i wont be on the snow for another 2 weeks and am dreading the 6 hour trip one way just to find out what i have isnt quite right... so thank you Snobyrd for your input and feedback!!!!
 
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snobyrd

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sure glad youve had some time on the snow and are willing to find out whats working.... im planning on running a 62-42.46---58-42.36 helix, stock springs, derlin washers, and polaris weights..... only thing is i wont be on the snow for another 2 weeks and am dreading the 6 hour trip one way just to find out what i have isnt quite right... so thank you Snobyrd for your input and feedback!!!!
What elevation will you be riding?
Run in eth mode if you can get non eth 91.
 
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snobyrd

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8-10k... actually gonna run 58-62 helix ( would run 60-40 if i had one) , blue/pink primary spring with polaris weights, derlin washers
58/62 or did u mean a 58/42?
I think that Blu pink is gonna engage higher than the stock? I prefer low engagement.
U should be pretty close if its a 58/42, just be prepared to run a few extra grms of weight and keep it under 8200 on the easy pulls.
 

madmax

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Are you really only getting 30 mph track speed? My 100% stock 18’ 800 162 does better than that at 10,000 up hill in super deep snow. My 20’ 850 Khaos with only 50 miles and stock clutching was gets 38-40mph only running 7900rpm. I would look through the TRS thread and do his alignment and clutching.
 
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snobyrd

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Are you really only getting 30 mph track speed? My 100% stock 18’ 800 162 does better than that at 10,000 up hill in super deep snow. My 20’ 850 Khaos with only 50 miles and stock clutching was gets 38-40mph only running 7900rpm. I would look through the TRS thread and do his alignment and clutching.
I don't think there's any mention of 30 mph in this thread, 30 mph would be in the first stage off the 62 deg than after it transions into the 42deg , I'm seeing 47 mph in under 20 ish second steep deep pulls.
One of the best things I like about this pipes power is the ability to chew hard on a steep side hill than hook it and go up.
 

HECKS

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Anyone know the angle of Indy Dan's MTN #1 Helix ?
I have one and ran it with his spring 140-200 and didn't care for it in the deep snow climbing.
I trying it this year with the stock 155/222 and it works decent against the straight 40. But this is on the 800 mind you.
 

Sheetmetalfab

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Anyone know the angle of Indy Dan's MTN #1 Helix ?
I have one and ran it with his spring 140-200 and didn't care for it in the deep snow climbing.
I trying it this year with the stock 155/222 and it works decent against the straight 40. But this is on the 800 mind you.

its a multi angle full progressive.

very similar theory to TRS clutching.

mountain #1 is for longest belt life and always loading the motor. (Det won’t happen unless your flyweight is way off)
 

madmax

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I don't think there's any mention of 30 mph in this thread, 30 mph would be in the first stage off the 62 deg than after it transions into the 42deg , I'm seeing 47 mph in under 20 ish second steep deep pulls.
One of the best things I like about this pipes power is the ability to chew hard on a steep side hill than hook it and go up.
Original post says, “At track speeds in that 30 mph range when im chewing hard”. Guess I took that to mean only getting 30mph when chewing hard.
 
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snobyrd

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its a multi angle full progressive.

very similar theory to TRS clutching.

mountain #1 is for longest belt life and always loading the motor. (Det won’t happen unless your flyweight is way off)
It sounds like his start is a 52 and full progressive..
I was emailing him yesterday, and one suggestion he had was to stay with my mtx weights or run his helix and add more grms to a pol weight.
 

HECKS

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In my experience with Dan's helix/spring combo was that it ran nice and cool. Tree riding was where it work well. I also have Dan's adj weigths and ran with his suggestions. Riding Revy area 5000-7000ft
On a steep climb in 1.5 - 2 ft of fresh is where I found it lacked with the 140/200 spring. I switch secondary's with a buddy on the hill and ran the stock str 40 and bested my previous mark by 40 - 50 ft in fresh track. I'm interest to see what the stiffer stock spring will be like on this helix. Last trip out the snow was setup to much to get a true test.
Next trip I will be packing helix's to swap on the hill.
 

Sheetmetalfab

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In my experience with Dan's helix/spring combo was that it ran nice and cool. Tree riding was where it work well. I also have Dan's adj weigths and ran with his suggestions. Riding Revy area 5000-7000ft
On a steep climb in 1.5 - 2 ft of fresh is where I found it lacked with the 140/200 spring. I switch secondary's with a buddy on the hill and ran the stock str 40 and bested my previous mark by 40 - 50 ft in fresh track. I'm interest to see what the stiffer stock spring will be like on this helix. Last trip out the snow was setup to much to get a true test.
Next trip I will be packing helix's to swap on the hill.

I’m guessing the secondary swap on the hill raised your operating RPM?

did you try the mtn one helix at that higher rpm? (Lowered flyweight)
 
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