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Perplexing results today??

Doc Harley

TY 4 Stroke God
Joined
Oct 17, 2016
Messages
3,400
Age
55
Location
Here & there
Country
USA
Snowmobile
'17 Sidewinder LTX SE
Last month testing:
MS16sm 8950 @ 72g & 8jp

Today:
Ecotrail 9000 @ 71.3 & XS825
PowerTrail 9000 @ 71.3 ^
Max17 9000 @ 71.3 ^

I'm struggling to understand why I'm pulling less weight with PM tunes. Also pulling the same weight with all three
I saw 9150rpm on Max, one time.
Something is not right. I'm starting to believe it's my homebrew muffler?!?! If it was muffler, it should run very good on Ecotrail or powertrail? Jmho
Please give guidance.....


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Last edited:

What is outside air temp and barometric pressure when you made the runs today verses last month?
 
Try your stk muffler tunes with your home brew muffler and see what you get, then try stk muffler with your stk muffler tunes, that will tell ya if home brew is bad.
 
The XS825 belt is going to drop some RPMs (~200 RPM) by itself, so probably why a little less weight is needed. The RPMs will be higher with the 8JP belt.
 
So, if I remember correctly, your tunes are all 2 bar tunes. I knew TD has both 2 bar & 3 bar tunes for Their MS16, but didn’t realize that the Max17 tune was also a 2 bar tune, but the MS17 is for sure a 3 bar tune.

Why I ask this?
I’ve had both Ms 16 versions, 2 and 3 bar tunes.
The MS16 2 bar gave me 15.9 - 16.2 lbs of Boost per the Hour meter on my pod.
The MS16 3 bar gave, and still gives me, 17.2 - 17.5 and will stay there. I can watch it climb from 1 all the way up to 17+ , dependent on how much throttle I am giving it.

So with your 2 bar tunes with the 2 bar sensor, you will not see your full boost no matter if it’s 16 or 17 tunes, but it will be accurate for the lower 15lb +- tune!

I also had problems dialing in a 17 tune last year, it was the MS 17 3 bar tune. It ran way fat and also took less weight then the MS16 3 bar tune??

Without an AFR gauge or the closed loop and also the ability to look at runs through software, it’s guess work!

Spoke with TD many times and got a lot of great info from many on this site, and from what I gathered,

I needed a CAI
Needed -35 F per, well I won’t go there, for it to run at it’s peek.
Needed higher octane fuel, but can expect knock light if only turning 8300-8500. 8900 9000 is a must!
Etc
Etc

I am back to the MS16 3 bar Sm tune.

Looking back at all, I will say that it was probably multiple things that put me sideways tuning.
New 15 mm rollers instead of stock size rollers.
New XS825 belt caused lower rpms then other 2 from previous years.
Fat tune,needed CAI or severe cold weather to run properly.

I also had a new muffler during this process, a TD SQ2.5”

I could tell you many things that were not the problem, like cam timing, etc!

One thing that I don’t have that you seem to have, is a close test spot, and this year is no different with lakes just now getting safe locally, and (family time) trips coming up!

Hope you find your Max 17 power and revs!
 
What is outside air temp and barometric pressure when you made the runs today verses last month?
Low 20's last month
High 20's today
Don't know barometric pressure.
Try your stk muffler tunes with your home brew muffler and see what you get, then try stk muffler with your stk muffler tunes, that will tell ya if home brew is bad.
Yes, you mentioned that before and I'm starting to wonder and looking in that direction.
Just can't put my finger on it, Brendan.
The XS825 belt is going to drop some RPMs (~200 RPM) by itself, so probably why a little less weight is needed. The RPMs will be higher with the 8JP belt.
Agree 100%. Most guys on Max17 with xs825 are pulling 74 g. And I'm at 71.3?!?!
But to be honest they never explained the RPMs they are running.
 
Hmmm. Max17 is my favorite tune. I just flashed my new '23 last weekend and ran Max17 with brand new xs825, Dalton weights empty at 70g (I had forgot the adjustable weights in my garage) B/O wrapped at 6/2 (80), and TD 3" Mod Stock Muffler. My RPM's were way too high at 9,600 Max. I'll be adding 3 grams to get to 73 grams when I come up on Wednesday. I too need to find out how much weight I need for Max17 to achieve the 8900 - 9000 rpm.
 
So, if I remember correctly, your tunes are all 2 bar tunes. I knew TD has both 2 bar & 3 bar tunes for Their MS16, but didn’t realize that the Max17 tune was also a 2 bar tune, but the MS17 is for sure a 3 bar tune.

Why I ask this?
I’ve had both Ms 16 versions, 2 and 3 bar tunes.
The MS16 2 bar gave me 15.9 - 16.2 lbs of Boost per the Hour meter on my pod.
The MS16 3 bar gave, and still gives me, 17.2 - 17.5 and will stay there. I can watch it climb from 1 all the way up to 17+ , dependent on how much throttle I am giving it.

So with your 2 bar tunes with the 2 bar sensor, you will not see your full boost no matter if it’s 16 or 17 tunes, but it will be accurate for the lower 15lb +- tune!

I also had problems dialing in a 17 tune last year, it was the MS 17 3 bar tune. It ran way fat and also took less weight then the MS16 3 bar tune??

Without an AFR gauge or the closed loop and also the ability to look at runs through software, it’s guess work!

Spoke with TD many times and got a lot of great info from many on this site, and from what I gathered,

I needed a CAI
Needed -35 F per, well I won’t go there, for it to run at it’s peek.
Needed higher octane fuel, but can expect knock light if only turning 8300-8500. 8900 9000 is a must!
Etc
Etc

I am back to the MS16 3 bar Sm tune.

Looking back at all, I will say that it was probably multiple things that put me sideways tuning.
New 15 mm rollers instead of stock size rollers.
New XS825 belt caused lower rpms then other 2 from previous years.
Fat tune,needed CAI or severe cold weather to run properly.

I also had a new muffler during this process, a TD SQ2.5”

I could tell you many things that were not the problem, like cam timing, etc!

One thing that I don’t have that you seem to have, is a close test spot, and this year is no different with lakes just now getting safe locally, and (family time) trips coming up!

Hope you find your Max 17 power and revs!
I'm with you 110%.
Jon (here) chimed in on another thread I started. He claimed through his AFR gauge that it was idling rich, which mine does, I can smell it.
I called TD the other day and I got an answer that was vague at best. In other words I think I'm right on the cusp of needing to step up or step down. Due to a couple various reasons.
Also, temps have a huge Factor in the performance of these tuned winders. I'm not in my favorite condition (temp wise) to make power. High 20's f.
In the end I think I'm chasing something that I need to wait for.
 
Hmmm. Max17 is my favorite tune. I just flashed my new '23 last weekend and ran Max17 with brand new xs825, Dalton weights empty at 70g (I had forgot the adjustable weights in my garage) B/O wrapped at 6/2 (80), and TD 3" Mod Stock Muffler. My RPM's were way too high at 9,600 Max. I'll be adding 3 grams to get to 73 grams when I come up on Wednesday. I too need to find out how much weight I need for Max17 to achieve the 8900 - 9000 rpm.
What temps are you commonly riding in and could you post up what your findings are?
We are running the exact same, other than my muffler is 2.5"
I am pretty confident it flows better than a 2.5" stock mod.
 
Last month testing:
MS16sm 8950 @ 72g & 8jp

Today:
Ecotrail 9000 @ 71.3 & XS825
PowerTrail 9000 @ 71.3 ^
Max17 9000 @ 71.3 ^

I'm struggling to understand why I'm pulling less weight with PM tunes. Also pulling the same weight with all three
I saw 9150rpm on Max, one time.
Something is not right. I'm starting to believe it's my homebrew muffler?!?! If it was muffler, it should run very good on Ecotrail or powertrail? Jmho
Please give guidance.....


View attachment 171348View attachment 171349
As mentioned the xs belt will pull rpm down a fair bit so less weight makes sense. Why the same weight on the 3 tunes that not making sense. A test like this be sure to use good gas 93-94 octane to be sure pulling no timing, if you don’t have data logging you would never know. I can see timing starting to get pulled on Max 17 on 91 octane at times, (likely not good 91) and never on 93. Or you have a boost leak and your turbo is struggling to make over 15-16 lbs?
 
What temps are you commonly riding in and could you post up what your findings are?
We are running the exact same, other than my muffler is 2.5"
I am pretty confident it flows better than a 2.5" stock mod.

Temps are commonly in the Teens to low/mid twenties (northern wisconsin). I think last Saturday was around 19 degrees. Yes, similar setups. I do also have the 3bar map sensor and closed loop. Looking forward to our 4-day 700 mile trip we have planned next weekend up to Bents. Hoping to find the right weight I will need. Thinking 73 or 74 grams will be the answer.
 
As mentioned the xs belt will pull rpm down a fair bit so less weight makes sense. Why the same weight on the 3 tunes that not making sense. A test like this be sure to use good gas 93-94 octane to be sure pulling no timing, if you don’t have data logging you would never know. I can see timing starting to get pulled on Max 17 on 91 octane at times, (likely not good 91) and never on 93. Or you have a boost leak and your turbo is struggling to make over 15-16 lbs?
I live in the world of 91 (non-ethanol) so I've found 1oz of boostain per 10 gallons will shut the deto lights off.
Also testing in 25° f+/-.
I did a boost leak test last week I found when decompressing from 20 psi to 10 psi that the needle from 20 to 16 1/2 swept fairly quickly and then slowed down. After securing all the clamps I had a nice steady progression on the needle from 20psi down to 10psi. I then stopped watching gauge.
 
Temps are commonly in the Teens to low/mid twenties (northern wisconsin). I think last Saturday was around 19 degrees. Yes, similar setups. I do also have the 3bar map sensor and closed loop. Looking forward to our 4-day 700 mile trip we have planned next weekend up to Bents. Hoping to find the right weight I will need. Thinking 73 or 74 grams will be the answer.
I'd love to make that Bent's camp, 100%
But I fear I would be more into tuning than enjoying.
Temps down here are going to be in the 40s this next week.
I honestly don't think I should even be testing in 20° F and above. Especially for Max17.
I'm thinking you'll be close either way.
They say as boost goes up your rpm should go down. 8900rpm sounds like a safe plan.
 
Did you replace your stock BOV? Mine leaked at 15 PSI?
Yes replaced with turbosmart. And talking with another member I put my stock bov back on there and it did the same thing as yours.... Right at 15 psi you can hear it hissing out the side.
 


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