Philip944

I am having some difficulty sourcing automotive 100 octane fuel for my incoming Radical SR3 1500. I understand that the radical doesn't have a knock sensor so I have to worry a bit about denonation. Anyone run 100 octane Low Lead avgas in their engine? Any issues? Should I just buy track gas at their ridiculous markup? Any major differences in Avgas and Mogas? Thanks!

Circuit Motorsports

Ran it in my Formula Car a while back.

No issue on that engine. I would double check with the builder/Radical and see what they have done in the past.

Generally you have to find a place that will fill it into something other than a plane. The smaller airports with self serve pumps are the place we used to get it. Just needed a tail number to unlock the pump.

LuigiVampa

I know this isn't answering your question but sometimes race fuel can be hidden right under your nose.

Many Sunocos carry 5 gallon pails of the stuff or will order them if you ask.

MarcD147

http://www.sunocoracefuels.com/fuel-...0-gt&range=300

Philip944

yeah, used that before I posted. Not much within 30mi. Everything close is 110-114 leaded. Thanks

Sboxin

You might look at sources that supply off-road fuel - we have found some at a truck stop in the West - 100oct unleaded - price is only a $1 cheaper than track source but still expensive . . .

Regards,

rlm328

The only issue with leaded fuel is O2 sensors, they usually do not play well together.

Philip944

Agreed. Really wanting to stay unleaded. I may just order a drum from Sunoco.

Thanks for all for the replies and tips.

CharleyH

I have not used AvGas in my Radical, but MANY years ago I worked as an aviation (A&P) mechanic and was taught to never use AvGas in a car. 100LL has more lead in it than leaded auto fuel. Out here in CA the cost of race fuel is the same at the track as it is at local stations ($9.75/gal), so I usually fill up at the track and only bring fuel if I am concerned that the track won't have it. If I remember correctly the 1500 burns about three gallons per 25 minute session and the car holds 12 or 14 gallons (I need to check my notes).

Charley

Matt Romanowski

If you have any oval short tracks (or any other racing really) near you, one of the gas stations nearby will have some race fuel available. Just make sure wherever you get it doesn't have old, bad gas.

stownsen914

You can also try speed shops that specialize in motorcycles and off-road bikes/ATVs/snowmobiles, etc. Or call the Sunoco and VP regional distributors that are near you and ask which retailers near you that they deliver to.

I have also heard that avgas is not ideal for automotive use. I don't have great information on why, but I think it has to do with the different use case it is designed to serve (plane engines that run at moderate, constant RPM and at high altitude / thinner air).

d15b7

i've run 100LL in my race cars for over 20 yrs now (Lotus super seven with 11.5:1 compression Kent crossflow motor and a Honda Civic with K24 turbo engine). zero issues with the 100LL -- it has worked perfectly in both cars. the Lotus has no electronics at all; no knock sensor and no O2 sensor. Honda runs in Open Loop with the O2 disabled but does run a knock sensor. Lotus makes about 165 crank hp; Honda makes about 400 crank hp. no detonation ever on either. spark plugs always look fantastic (good color and no signs of det). 100LL is fantastic if you will be letting your car sit for extended periods of time; there are antivarnish and antigumming agents in it and it is supremely stable.

one thing to remember is even though it is called 'low lead' it is NOT low; there is a lot of lead in 100LL. it will def foul oxygen sensors and wreck cats.

I buy it at a local small airport and pump it into 5 gal cans and take with me (usually buy 7-8 cans at a time). local price is about $4.40 a gal right now.

EDIT: forgot to mention that I run 100LL exclusively in all my small engines too (for the last 8 yrs or so). all chainsaws, pushmowers, snowblowers, etc. they all now start on the first or second pull after sitting for 12 months. never have to rebuild a carb or fight trying to get them running properly (esp the chainsaw which sometimes sits for 2-3 years without use).

85Gold

I will leave this here and there is more reading available just search the interwebs


http://www.fuelexpert.co.za/canirunavgas.php

Peter

d15b7

I'll leave this one here too

http://www.apexspeed.com/forums/showthread.php?t=33425

Formula Ford runs the same basic motor as I have in my Lotus (well, the older ones do; now they are all switching over to the 1.5 Honda plant). main difference between my Lotus and a 'legit' FF is that I have much higher compression, much more agressive cam grind, much bigger carb(s), and more displacement and a lot of head flow work (I make a touch over 160 crank hp at 7000 rpm vs a FF motor might make 110 hp at prob 6000 rpm). LOTS and lots of the FF guys I race with at a Vintage weekend run the AVGas 100LL, and have done so for decades, without issues.

in the thread link above, the discussion is heated; interestingly, the info given stating how 'bad' the 100LL is, is from a race fuel company's website. further down, many/most of the FF racers chime in with their personal experiences running the 100LL for years and years; none of them had experienced any of the issues stated by the racegas company.

I can not tell anyone to use 100LL and with certainty say 'no chance anything will be harmed'; but I can say with certainty that since about 1992 I've logged over 20k race miles between my Lotus and Honda and have experienced ZERO fuel related issues. the Lotus motor has been rebuilt twice in that timespan (first time was the main and rod bearings got wiped out due to oil starvation; hadn't had the Accusump installed at that time). second time was about 8 years later when the timing chain disintegrated at WGI at high rpm (engine builder never knew why that happened; he had never seen it do that before in a xflow motor) breaking the lifters/pushrods/cam lobes and scattering broken metal all through the engine. both rebuilds, I had the entire engine rebuilt/gone through; other than the major oil system destruction both times, the engine was totally healthy (I still did have the valves recut and the seats done and new valvesprings and rings and a rehone; it was a 'as long as I'm in there' sort of thing. I'm sure you racers out there know all about that! lol $$). I've never had any premature ring wear, or valve guide/seat wear, and my spark plugs look fantastic after 2 years of racing (at that point I change them because I feel 'bad' haha. they still look great but for $2 each I figure 'why not'?). I have solid lifters on that motor and I check the clearances the beginning of every year; they barely move (maybe get 0.001" tighter due to wear; the tolerance on that motor is 0.003").

so, on my particular motor, I can say with 99% certainty, that the 100LL has not hurt me at all, and in fact has probably saved me thousands and thousands of dollars over the years on race gas cost.

the Honda is a very different, 'modern' kind of motor when compared to my Lotus; it's a higher rpm motor (8500 rpm vs 7000 rpm) and is 4 valve, with VTEC and iVTEC. compression ratio is 9.5:1 with a turbo at a relatively low boost level of 15 psi. crank hp is 400 on 100LL. I have run E85 on my Honda and it makes at least 15% more power on E85 vs 100LL (mostly due to the fact that when we retune, we can run a lot more ignition advance on E85). I stopped using E85 because of several things -- it was tough to get E85 that was consistantly E85 (and not E81 or E72 etc); when the blend was changing like that, it was dangerous for the motor (detonation!). also, E85 doesn't store well at ALL; like, after a month I had to throw it out due to degradation. lastly, it was a super pain in the *** to have to drain the E85 out of the gas tank at the end of a race weekend, and put in 2 gals of regular gasoline, and then run the car for 5 minutes. this had to be done or the injectors would corrode and the fuel pump would fail if it sat any length of time. then before the next race weekend the gas had to be drained and the E85 added before driving it. it was such a headache that I quit doing that; I'd rather have 100LL in there that I can leave in for an entire year and still start it right up and go out on track with zero issues. I'm willing to give up the 50-60 hp that E85 was giving me; it just wasn't worth the risk and headaches.

OK -- that's my total personal experience with the 100LL; not something I read on the interwebs; I've lived it!

Todd

PS your mileage may vary (pun intended!)

bpu699

What's the scoop with octane boosters? Eastwood and Pegasus racing sell them. Wouldn't it be easier to pour a couple cans of that in instead?