tonykof
Expert
What part of the overall jetting curve does the Pitot jet system on a Bender II effect the most? It seems like it's more the lower end & not too much on the top. What do you guys think?
Thanks Tony
Thanks Tony
Pitot jet effect on Bender II?
- Thread starter tonykof
- Start date
BigDog05
VIP Member
My pitot jet doesn't seem to do much of anything until wide open throttle.
At 2800 ft and approx 20F, I'm running 135 mains, and 700 pitot@ 4-6psi boost and 600 pitot @ 8-10 psi of boost.
If I run the 600 @ low boost, my A/F guage will show rich at 10.2- 10.8.
With the 600 @ 8-10 lbs of boost its right at 11.8-12.0. This is all WOT.
I think I finally have it dialed in and will try higher boost next season.
No Snow this year.
At 2800 ft and approx 20F, I'm running 135 mains, and 700 pitot@ 4-6psi boost and 600 pitot @ 8-10 psi of boost.
If I run the 600 @ low boost, my A/F guage will show rich at 10.2- 10.8.
With the 600 @ 8-10 lbs of boost its right at 11.8-12.0. This is all WOT.
I think I finally have it dialed in and will try higher boost next season.
No Snow this year.
tonykof
Expert
Hi,
I'm at about 1000 feet. I also am running 135 mains & am rich.. Where are your needles set? What pilot jets are you running? fuel screw?
Thanks much.
tony
come to MN we still have good snow!
I'm at about 1000 feet. I also am running 135 mains & am rich.. Where are your needles set? What pilot jets are you running? fuel screw?
Thanks much.
tony
come to MN we still have good snow!
BigDog05
VIP Member
I'm running 20 pilot jets at 1.5 turns off seat. Needles are one notch rich with green Holtzman springs. With this set up prior to the green springs, with stock springs, my A/F guage would read 15.2 -15.9 at cruise,under no load. That made me somewhat nervous so I'm going to try the green springs. Put them in the sled in early Feb, but have not had any snow to test.
With the 20 pilots at approx. 950 ft elevation (my garage), I get a reading on the A/F of 14.5-15.0 @ idle, and it richens up a little at 2800ft. Also at 3500-4500 on the stand in the garage and stock springs I get 15.9-16.9 on the A/F. With the green springs I get 13.9-14.2 A/F. Guessing the green springs will be fine on the snow.
I may not have expressed myself very well when I said that the pitot does not do much except at WOT. Probably a better way to put it, is not to use the pitot jet to fix anything other than WOT.
My sled seems to need more jet than a lot of guys on here. Last year I did not have an A/F guage, only an EGT guage and it would get to 1350-1400 in the cruise area real fast. I would go down to a 300 or 400 in the pitot to help that problem and it would get pig rich at WOT.
Use the pitot to get your WOT and then needles and springs, and pilot jets to do the rest.
Also if you are still running one hose from under the intercooler to both carb vents, change that to two hoses. Spray 25 was the first to get that straightened out.
With the 20 pilots at approx. 950 ft elevation (my garage), I get a reading on the A/F of 14.5-15.0 @ idle, and it richens up a little at 2800ft. Also at 3500-4500 on the stand in the garage and stock springs I get 15.9-16.9 on the A/F. With the green springs I get 13.9-14.2 A/F. Guessing the green springs will be fine on the snow.
I may not have expressed myself very well when I said that the pitot does not do much except at WOT. Probably a better way to put it, is not to use the pitot jet to fix anything other than WOT.
My sled seems to need more jet than a lot of guys on here. Last year I did not have an A/F guage, only an EGT guage and it would get to 1350-1400 in the cruise area real fast. I would go down to a 300 or 400 in the pitot to help that problem and it would get pig rich at WOT.
Use the pitot to get your WOT and then needles and springs, and pilot jets to do the rest.
Also if you are still running one hose from under the intercooler to both carb vents, change that to two hoses. Spray 25 was the first to get that straightened out.
tonykof
Expert
Thanks Bigdog,
I did do the 2 lines thing & I'm running my needles 1 notch richer (raised) with blue springs. I'm not any too rich there I believe I'm around 14.1-15.6 at cruise under low load.
I'm running 17.5 (stock pilots) 2 turns on fuel screw & I'm pretty fat at idle, about 10.9-11.8..
At 12 psi boost I'm still kinda fat at WOT to the tune of about 10.5 -10.8 with 135 mains. Oh & a 500 pitot jet. Sled runs pretty good but I do have a little blubbering when I hammer the throttle.. I'm not sure if my problem is the rich pilots or the rich mains.. Since I don't have any 15 pilots I was thinking I would turn the fuel screws in to 1 1/2 from 2 & see if that helps.. If it doesn't I'll probably try my 700 pitot jet & see if that helps.. I may have to pick up some 130 - 132.5 main jets & try that too.. What do you think? Am I on the right track?
Thanks
tk
I did do the 2 lines thing & I'm running my needles 1 notch richer (raised) with blue springs. I'm not any too rich there I believe I'm around 14.1-15.6 at cruise under low load.
I'm running 17.5 (stock pilots) 2 turns on fuel screw & I'm pretty fat at idle, about 10.9-11.8..
At 12 psi boost I'm still kinda fat at WOT to the tune of about 10.5 -10.8 with 135 mains. Oh & a 500 pitot jet. Sled runs pretty good but I do have a little blubbering when I hammer the throttle.. I'm not sure if my problem is the rich pilots or the rich mains.. Since I don't have any 15 pilots I was thinking I would turn the fuel screws in to 1 1/2 from 2 & see if that helps.. If it doesn't I'll probably try my 700 pitot jet & see if that helps.. I may have to pick up some 130 - 132.5 main jets & try that too.. What do you think? Am I on the right track?
Thanks
tk
BigDog05
VIP Member
I am certainly no expert at this, but I know that Skydog tried the Silver springs and they were way too light. The blue springs are even lighter than the silver ones.
Skydog said that the sled was way rich with the silver. I have a set of silver ones that I have not tried yet, because of skydogs result. I bought green to try first.
I would put the stock springs back in and if still rich I would try a 600 pitot as starters. Then try a 650 or 700. They are sure a lot easier to change than the mains for a test run.
Again, if I'm wrong someone will jump in, but it sounds like the slides are opening too fast causing the burbling when you hammer it.
Also I would only do one thing at a time so you know what did what.
My sled seems to need more gas on the bottom. Was real lean with 17.5's at 2 1/2 turns on fuel screw.
Skydog said that the sled was way rich with the silver. I have a set of silver ones that I have not tried yet, because of skydogs result. I bought green to try first.
I would put the stock springs back in and if still rich I would try a 600 pitot as starters. Then try a 650 or 700. They are sure a lot easier to change than the mains for a test run.
Again, if I'm wrong someone will jump in, but it sounds like the slides are opening too fast causing the burbling when you hammer it.
Also I would only do one thing at a time so you know what did what.
My sled seems to need more gas on the bottom. Was real lean with 17.5's at 2 1/2 turns on fuel screw.
BigDog05
VIP Member
I really think you will get the WOT thing in the ball park real quick with the 600 or 650 pitot jet. I don't remember off hand but you may have to get jets that big in increments of 20. I think anything above 540 goes up in sizes of 20.
I also think the stock springs will get you very close if not a tad lean.
I also think the stock springs will get you very close if not a tad lean.
BigDog05
VIP Member
I think rxrider is using the green springs and likes them.
tonykof
Expert
Yeah, I do have a red, green & stock set of springs I could try.. I put the fuel screws at 1 1/2 & it's pretty good I only get a very slight studder, runs better than it ever has (and it didn't run bad before!) Went to another Radar run this weekend but I got there a little late & it wasnt' scrapped down to ice so was very chewed up sugar snow & my M-10 didn't like it very much, I know some of the sleds that went earlier lost 10+ mph by th etime I got there... Still got the fastest time at 109/1000 ft. But I'm pretty sure I could have added 10 mph if i would have been there earlier..
We still have plenty of snow up here in northern MN, I live on Lake of the Woods & the lake is as smooth as I've ever seen it.
Thanks again for the help.
tony
We still have plenty of snow up here in northern MN, I live on Lake of the Woods & the lake is as smooth as I've ever seen it.
Thanks again for the help.
tony
SledheadAlaska
Newbie
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AM here in Alaska and I change pitot jet at 2500, 4500 and 6000 feet as the engine starts running rich. On stage I at 450 feet 300 pitot worked well. At 2500 feet I went to 400. At 4000 feet I went 520. The Bender instructions can be thrown out once one corrects all the tubes. At 6000 feet on Stage II I ran 520 and it ran a little rich.
I have a bender rear turbo and changed the lines to the slides and fuel regulator. I put in carb springs for 4000 to 8000 feet. Raised the needles a spacer. AF guage states I am right on except for a little lean around 2000 rpm to 4500 rpms. Here I run lean.
I have a bender rear turbo and changed the lines to the slides and fuel regulator. I put in carb springs for 4000 to 8000 feet. Raised the needles a spacer. AF guage states I am right on except for a little lean around 2000 rpm to 4500 rpms. Here I run lean.
Turbo Tubster
Newbie
Pitot Jet Bender II
I'm also in alaska and have been running for two seasons now. My jetting is stock, 14# wide band and pitot has only affected wide open throttle. Am currently running 780 pitot and 10.9-12.4 0n wide band, sea level to about 2500.
I'm also in alaska and have been running for two seasons now. My jetting is stock, 14# wide band and pitot has only affected wide open throttle. Am currently running 780 pitot and 10.9-12.4 0n wide band, sea level to about 2500.
Silver springs yes they did not work for me at all! Took them out in about 3 mins of riding! Now i ran two lines to the slides and put in the stiffest after market springs. Forgot the color----sled is put to sleep now for along time-----been fun boys!!!!
Skydog
Skydog
