I was wondering about boost levels/altitude with 100% pump fuel. I am trying to decide if I should go 100%AV at 10 lbs or 100% pump at 6lbs. Any thoughts?
Eli
Eli
Pump Gas...boost levels
- Thread starter Eli
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J
Jkinzer
Well-known member
i run a trail tank which when bone dry will take just under 16 gallons of fuel, i run 3 gallons of 109 motor octane race fuel in with every tank, so 13 gallons of pump gas. many people have the opinion that this is stupid but it works and my theory is that it has to help a little with how chity our premium pump fuel is. my local "pump gas" is non ethonal which helps as well though. i ride from 6-9k feet in the mccall area and run boost levels from 10-12 lbs depending on my elevation. i have over 2k miles on my sled this way with not one issue. the season before with the 09 head i ran straight race gas at 14lbs of boost for 3000 miles with no issues either, but the difference between 14lbs on race gas and 11-12lbs on pump gas is minimal if at all. i feel i wasted a lot of money on race fuel that could have been put to better use. My motor was built by indy dan and completely gone through, blue printed the works... so that probably has a little to do with the boost levels i can run. but i do have 2 other TD8's that i ride with all the time that run pretty close to the same boost levels on the same fuel set up
I just picked up the sled....'10 head and pistons with '09 flash....twisted kit with 2860 turbo. My worries with 100% pump fuel is getting a bad batch, where a 100% AV I don't think that would be a concern. How about power levels at 6-8 lbs compared to 10-12lbs? Are most keeping the det sensor bolted up?
J
Jkinzer
Well-known member
with the 09 flash you should have no problem keeping the det sensor bolted up. wherever you decide to get your fuel just make sure you always get your fuel from the same place every time if you can, will give a little more consistancy. as far as a bad batch there is always the possibility, if you can get av gas for around $4-$5 a gallon its almost worth it. but if you have egt's on your sled you will get a pretty good idea as far as what you can do at what boost level. once your sled is dialed in (tuned through 02 sensor, plug band, piston wash) you can or at least i do read off of my egts, i run my sled at 1280-1300 degrees as much as i can, my alarms are set at 1315 and the power difference between 12000 and 1300 is insane. as far as the power difference between 6-8lbs and 10-12lbs its almost like the difference of not having a turbo compared to having one. once you surpass 10lbs of boost you start to get a lot more power per pound of boost pressure. just the difference from 10lbs to 12lbs is similar to the difference between 5lbs and 9lbs
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WHEN YOU SPEND THAT MUCH MONEY ON YOUR SLED, WHAT IS IS WRONG WITH RUNNING A FEW GALLONS OF RACE FUEL? ABSULUTELY NOTHING....in fact its a smart thing to do.....why not buy yourself a little bit of insurance?
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SNOW JW
Well-known member
I agree a mix of race or AV fuel is your best option. I use AV most the time. Also I get about 1.5lbs more boost with the intercooler as well with the colder charge temps.
Another thing to note is the EFI tune has allot to do with your boost levels as well as the stock ECU mapping and what map you have. If you have a EFI box that will adjust to your charge temps via ADA and allow you to stay away from lean spots that can strike up some DET this will get you more boost as well.
Another thing to note is the EFI tune has allot to do with your boost levels as well as the stock ECU mapping and what map you have. If you have a EFI box that will adjust to your charge temps via ADA and allow you to stay away from lean spots that can strike up some DET this will get you more boost as well.
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Jkinzer
Well-known member
since we're using caps here to get the point across. BECAUSE I DONT HAVE TOO! SO WHY WASTE MONEY? if you would read the earlier posts, my motor isnt stock. obviously i can do what i've been doing because i've been doing it for 2000 miles. the lowest octane fuel you can run with out detonation the better your machine is going to perform, hints more power will be created. i know my sled very well, have over 5 thousand miles seat time on it. and if you read my first post i do run a "few" gallons of race gas 109 motor octane race gas to every tank. so what is the purpose of your caps lock post?
My two cents to try to help here.
50/50 110 to pump gas 91 (about 106/88 MON) ends up at about 97 MON octane
Straight 100LL Av Gas about 104 MON...with considerably different thermal character. (affects throttle response and cold starting)
Considerable difference in octane...
The two are not direct replacements for each other.
A setup that would run well an the 110/91 mix would not run the same as Straight Av gas on the same fuel and boost settings...The Straight 100LL would be over octane in the 110/91 mix.
Kinzer, at 109 MON... I assume you are using Sunoco Supreme 112??
Besides the octane increase of 3 MON points over the Standard-110, it also has much different burn characteristics, and a 12% lower Reed Vapor Pressure (RVP). This will change how the sled starts and runs.
At approx 20% mix of race-to-pump (3 gallons race in 15.5 total volume) ... you are at about 96 MON with your 112 fuel... But the octane is only part of the story as 112 has different thermal/density properties that might just make it a better mix, for you, than the 91/110 (R+M/2) mix at 50/50.
You also bring up an important point on the non-ethanol... inconsistent in quality.
If you want to mix with AV Gas... IMO... you need to find NON ethanol and confirm that this fuel has ZERO Ethanol or other oxygenates in it.
One more BIG point to make... The ideal fuel for WFO hillclimber is not necessarily the same fuel as a technical boondocker that is cycling the throttle often.
My 2 cents.
BTW MON... Motor Octane Number
50/50 110 to pump gas 91 (about 106/88 MON) ends up at about 97 MON octane
Straight 100LL Av Gas about 104 MON...with considerably different thermal character. (affects throttle response and cold starting)
Considerable difference in octane...
The two are not direct replacements for each other.
A setup that would run well an the 110/91 mix would not run the same as Straight Av gas on the same fuel and boost settings...The Straight 100LL would be over octane in the 110/91 mix.
Kinzer, at 109 MON... I assume you are using Sunoco Supreme 112??
Besides the octane increase of 3 MON points over the Standard-110, it also has much different burn characteristics, and a 12% lower Reed Vapor Pressure (RVP). This will change how the sled starts and runs.
At approx 20% mix of race-to-pump (3 gallons race in 15.5 total volume) ... you are at about 96 MON with your 112 fuel... But the octane is only part of the story as 112 has different thermal/density properties that might just make it a better mix, for you, than the 91/110 (R+M/2) mix at 50/50.
You also bring up an important point on the non-ethanol... inconsistent in quality.
If you want to mix with AV Gas... IMO... you need to find NON ethanol and confirm that this fuel has ZERO Ethanol or other oxygenates in it.
One more BIG point to make... The ideal fuel for WFO hillclimber is not necessarily the same fuel as a technical boondocker that is cycling the throttle often.
My 2 cents.
BTW MON... Motor Octane Number
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From what I have seen, I would not go above 6.5 lbs with pump gas. 7 or more you should have some race in there. It all depends on the sled to bigger bore sleds moving more air require higher octane at lower boost levels, for example an 600 may be fine at 8 lbs, but 6.5 is limit for 800, and 5 for 1000s.
Hope this helps.
Hope this helps.
Has anyone ever found the limits of both 50/50 110 and straight av on the same sled? Thanks racinstation for the info.
In general... 100% 91 (no ethanol) you are looking at a practical limit on the 8s at around 7 lbs if everything is "correct"
On 100% 100LL.... IMO.... You are looking at 11 - 12 lbs depending on setup.
Questions to ask yourself...
What do you want to do with the sled?
What is your skill level? (A 10 + lb 800 is a hand full in the trees)
Do you have non-ethanol in your area availble?
I don't think there is non-oxygenated fuel handy here, so straight av gas is probably the way I'll go. If I have to even mess with a couple gallons of race fuel to cover my butt on pump fuel, I may as well go 50/50 or straight av and have some fun. Can you even run 10% ethanol pump fuel?
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POLARIS600cc
Member
At about 1500ft here in MN, I ran 10psi on straight 100LL, 7psi with 8gl pump premo(10% ethanol) and 2gl 100LL.
I wasn't able to make it outwest last year(stupid economy). This year outwest im going to start at 12psi on straight 100LL and try workin up to 14psi. this will be 8000ft+
Im running stock motor with a silber turbo setup except using holley 2:1afpr and purelogic control box.
edit: sled is 07 700 dragon, i forgot i don't have sig anymore
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POLARIS600cc
Member
Whats the reasoning behind this?
T
treedocker
Well-known member
i ride from 6 to 9 thousand feet and i run 7 to 8 lbs with 91 and 1 galln of sunoco 112, i have never had a problem yet 1600 miles on my sled this last year
I run 50% 110 to premium pump with no issues at 12-14psi and am verry happy with the performance, I can also tell you that my XP 800 with clutching will kill my dragon at 9-10psi ,, dont wast you time with low boost unless you run out of fuel ,,you got a turbo for a reason ,,,,remember?????
T
theshadowrider
Well-known member
Is your xp boosted? Let me get this straight, your XP 800 normally aspirated will "kill" your dragon running 9-10 psi boost? Something doesn't seem right?
Last season was my first turbo experience, I had a damb hard time converting from carb mentality to electronic but made great strides in the end. I ran 50/50 race and pump at 8lbs at 1700ft to 10,000. IMO 8lbs is just barely ok. I'm going to 10 or 12 on Kinz's gas mix and only going to ride it at 5000 and above. I just can't wait for it to snow.
J
Jkinzer
Well-known member
might be cutting it close at 5,000 feet. but let me know how it works, i have a place about 20minutes from my house that i ride once or twice a year that starts out around 4600ft and goes up to 6500, ran 9-10lbs there last year with good results but never turned it up any more for the main reason that i didnt need it, not big power terrain
Yes the XP runs good and no turbo!! and so does the dragon,,, over 10psi And Im talking drag race 8-9psi is just plain LAME!! life begins at 12psi,, like Kinzer stated the difference between 8-9 and 12-14 is amazing,,!!!!!!!
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