Running avgas in stock D8 at low elevation?

[600xc4me]

I just picked up some avgas today. Mixed 5 liters of it in with 10 liters of 87 pump gas, and it seems to run stronger. But not sure how much a guy can safely run? As I under stand it runs cooler, but was also told that it makes the sled run hotter? Doesn't make sense to me. Have drag races coming up this weekend, and was thinking I would try the stuff ans see what it does. So far so good. But I am wondering how much you can safely run, and how much you can run before your running to much and losing any gains you might have had with a bit less. Motor is stock totally stock, running at about 1400'

 

[up-high]

Av gas burns slower than regular or premium.It doesn't make any more power than other gas. It was designed to stop detonation in high compression engines(airplane engines - engines that run at altitude). Allowing the motor to run higher compression thereby allowing the motor to make more power at altitude. Every 1000' gained in altitude means a 3%(roughly) loss in engine power due to the decrease in oxygen. Running avgas in a stock engine at low altitude will probably cause a loss of power due to the slower burning nature of the avgas. If your going to the drags, mix some avgas with premium and add some nitrous. That way the avgas will be useful.

 

[happylilcuss]

X2 on the above post.. Your wasting money putting higher octane fuel in a stock motor.

 

[av8er]

i am an airline transport pilot ho owns 7 airplanes

running avgas on a stock d8 is a waste of money., if you had a race gas turbo, or high compression head then it ould help, but u will not get any performance gains on a stock d8 over super unleaded

 

[happyhour]

if you are seeing detonation i would mix it in to every tank if you are not seeing detonation it is not needed

 

[dragontales]

I've ran av gas in a few of my sled's and have had great luck with it. I recently had my d8 go down because of det since then I have been running 2 gal's per tank and the thing runs awsome I even gained some rpms up top but up in AK all you can get is 90 octane. Put a couple gallons in and give her a rip.

 

[AKSNOWRIDER]

I just picked up some avgas today. Mixed 5 liters of it in with 10 liters of 87 pump gas, and it seems to run stronger. But not sure how much a guy can safely run? As I under stand it runs cooler, but was also told that it makes the sled run hotter? Doesn't make sense to me. Have drag races coming up this weekend, and was thinking I would try the stuff ans see what it does. So far so good. But I am wondering how much you can safely run, and how much you can run before your running to much and losing any gains you might have had with a bit less. Motor is stock totally stock, running at about 1400'

bone stock dragon..run it on 87 if you want best power..av gas will actually hurt the power..bone stock I have run mine on 87 non ethanol fuel right at sea level with great performance...

 

[nanook]

Running higher octane in the current Poo 800 helps considerably, this engine loves quality fuel. Mine runs like a bag of crap with 87 w/ethanol, 2 weeks ago I put a full tank of Shell 93 with no ethanol and put in a can of octane booster in also and the sled never ran better, as a matter of fact it ran the best it ever has. 106 mph in 2/3 of a mile pull on a heavy base Switchback with my 300 lb *** on it, I can't complain about that performance. I also run a PC V and those of you who don't I highly suggest you do also.

 

[F-Bomb]

You ran 91.333 octane if your ratio was accurate. Depending on your state of tune, plug gaps, and type your setup can perform better at that octane versus 87. Normally and conventionally speaking you want to try to run the lowest rated octane that your engine will stay in time running to make maximum HP for the application. Polaris 800CFI is very sensitive to octane and each sled is independant to the next depending on alt air flow and sensor resistance. This is finite stuff but you can get a performance variation by messing with octane values on the same sled even stock.

 

[600xc4me]

Interesting responses. I have only had the det light come on twice this winter, once it came on steady, not flashing, and still held RPM, I let out on the throttle and it went off. The next time is was flashing and retarding the timing. But I was almost out of fuel, I filled up with reg 87 as always and it hasn't come on ever since. Figured I might have had some bad gas. My reason for running it isn't to see if I can get more power from it, I understand that for it to make a real difference I would have to have motor work done. But I was hoping for some more RPM possibly, or just a better crisper running sled. Polaris now wants us to run 92, and the only 92 I can get (PetroPass) is watered down and has methanol in it. Which polaris also doesn't want us to run in these motors. So I have been running good 87. I was thinking I can't lose if I'm running closer to what these motors want.

My current set up is 10-66's, slp green spring, which has a higher start and finish rate than stock, and a PC5 with dyno tecks second latest stock map. My R's are still at 7900-8100. Now and then I"ll see higher. It ran absolutely AWESOME for a while after I put the PC5 on it, (8250- 8350) but has come down quite a bit. Totally stock D8 with PC5 that I ride with is pulling 8300 with stock 68's and stock spring, so I'm not sure why mine is low. I figured it might like some more octane. Like I said it seemed to run stronger, but it's hard to compare, as earlier on in the day with straight 87 the snow was really wet, and when I tried running the mix it had hardened up some. So hook up was better. But it sure wasn't running worse, it hasn't run this strong for quite a while.

Thanks for figuring that out F-Bomb. I was wondering what kind of number I would be at now. My ratio was probably a bit off, as I don't have a really accurate way of measuring how many liters I put in, but it should be close. I'll keep it at about this mix for a while and see how it runs in the long run with it. Only got out for about 20 min last night to try it out. Plug gap is about how the plugs came, if I had a feeler gauge I might play with it a bit.

 

[AKSNOWRIDER]

XC, this is a plug out of my D-8 from today..3-5 ft fresh powder, no fuel controller..turning 8250-8350 all day long.....this was on 90 octane pump fuel with slp single....

 

[knee deep in it]

You ran 91.333 octane if your ratio was accurate. Depending on your state of tune, plug gaps, and type your setup can perform better at that octane versus 87. Normally and conventionally speaking you want to try to run the lowest rated octane that your engine will stay in time running to make maximum HP for the application. Polaris 800CFI is very sensitive to octane and each sled is independant to the next depending on alt air flow and sensor resistance. This is finite stuff but you can get a performance variation by messing with octane values on the same sled even stock.

F Bomb, I just bought a sled and it came with a 55 gallon drum of 110. I wont be able to use it before the end of sled season so I am considering using it in my car.

I have a BMW 525 that requires 91 octane minimum. What ratio of 87 regular gas would i use with the 110 to achieve a 92 or 93 octane mixture?

 

[skibreeze]

F Bomb, I just bought a sled and it came with a 55 gallon drum of 110. I wont be able to use it before the end of sled season so I am considering using it in my car.

I have a BMW 525 that requires 91 octane minimum. What ratio of 87 regular gas would i use with the 110 to achieve a 92 or 93 octane mixture?

DO NOT run that fuel in your car, it is leaded fuel. Not good for o2 sensors and catalytic converters.

 

[knee deep in it]

thanks for the help

does anyone in calgary want some cheap 110? I have about 100 litres that wont be used this spring. $1.50 a litre is about half of what it costs by the barrel.

 

[F-Bomb]

3 gallons of 110
+ 10 gallons of 87 = 13 gallons of 92.3

3.5 gallons of 110
+ 10 gallons of 87 = 13.5 gallons of 92.9


4 gallons of 110
+ 10 gallons of 87 = 14 gallons of 93.57

 

[guidoxpress]

does anyone in calgary want some cheap 110?

if you ever head down south into Montana...get ahold of me..i would consider taking it ALL off your hands..

While we are aon the subject of AVGAS...if one was to run STRAIGHT 100LL AVGAS in a sled (05 Carls 975cc)...should "he" ok "me" mix oil in the fuel since its such a dry fuel??

also, would the plug gap need to be adjusted other then stock (.028")

good info in this thread...

 

[600xc4me]

I think next time IM in montana we need to hook up and go for a ride.

 

[guidoxpress]

I think next time IM in montana we need to hook up and go for a ride.

HELL yeh bro...i know some spots thats dope...will be there this weekend..with skisucca

bring that guys 110 barrel with you

 

[600xc4me]

HELL yeh bro...i know some spots thats dope...will be there this weekend..with skisucca

bring that guys 110 barrel with you

I am temped to plan a trip next year to ride with Brandt, if that ever comes to pass then we will totally swing by your area for a few days. Long drive but I think it would be awesome fun! haha if I come I will certainly do that.