Race fuel v Pump gas

[SRT17]

I have a sbc 355 flat top, mild cam, 70cc 441 heads. I am thinking about switching to pump gas to cut cost. RF is $8.25 a gallon around here.....I have always ran RF in it ...What are the pro's and con's.... Thanks

[save the racers]

On our spec head motors that are 64 cc.Made the same power on 110 as it did on 91/110 mix. Lost power on 87/110.If your fuel is 110 I would cut it 50/50 with 91.Back in the day we ran the 441 on 93 pump gas ,there was no margin for error.The first time we angle milled them it detonated and got a piston.

[dereksehi]

I would run aviation fuel its 100 octane and is substantially cheaper than race gas. I absolutely would not mix race fuel and pump gas as you will never get a consistent blend due to the leaded racing fuel being heavier than pump gas mixing fuel from an engine builders standpoint is asking for trouble.

[dereksehi]

I've been running av gas for 8 years and have several customers that run it and have never had any issue with detonation. Sure if you are running 11:1 or more compression I would use racing fuel but with the lower compression engines I've never had a single issue. There are different grades of av gas I use 100LL which is dyed blue.

[Racer96m]

Avgas is not 100 octane by the same standards as race or even pump fuel. That stuff is junk,

Actually Aviation gas is held to a much higher standard than other fuels, you just have to know what your getting. It has a lot of additives in it to prevent microbial growth and resist icing. The Blue 100/130LL is Low lead the 100/130 rating is 100 lean and 130 rich, its most commonly called 100LL. There is also Green which is a high lead content and also rated at 100/130, its the same as blue except for the lead content. There is also a Purple Avgas that is called 82UL, its basically low grade pump gas unleaded. Some confusion comes into play because back in the day Purple was the good stuff rated at 115, but they discontinued it because of low use and brought the color back for this 82UL crap.

Dave

[Racer96m]

Dave why don't you try helping people on here with some useful information instead of just trolling me? I had to unblock you just to confirm what I already knew. Your post wouldn't reference the original posters question in any way.

Were all on the www, we can all look up the colors and specifications for av gas.

Yes Jeff, you know everything. I have worked in Aviation going on 30 yrs now, so this might be a subject that I have forgotten more about than you will ever know. Have a nice day

Dave

[72Dubya]

Pump gas is very inconsistent and unreliable. Racing fuel is worth the extra cost in the long run IMO. I would rather spend an extra $1000 per year on fuel instead of $5000 on a new motor.

[dirtplay18]

Switched my 9:1 compression sport mod engine to 93 octane pump gas to cut costs last yr, and had no issues. Didn't notice any performance differences, and the plugs always looked great. Only thing I made sure of was to buy my fuel from a reputable gas station.

[glover11]

Working in aviation or if you know more about something than me, have nothing to do with the original posters question and neither have any of your replies... Your just a troll. Its freaking AMAZING how bent you get, when a guy gets on here and trys to help others out. You absolutely are AMAZING Jeff.

[SRT17]

I was not wanting aviation fuel. My compression is around 9.39:1... What would I have to do to convert to PG. Jets are 76 and 34 deg total timing. Thanks....

[glover11]

The only thing i see Jeffery, is that you got schooled on something you clearly don't no much about. Besides stating that you blew a bunch of your engines up years ago when you was still learning etc,etc, etc.............

[Hurst390]

Av gas has a higher reid vapor pressure than pump gas.It is harder to vaporize it at sea level.

[Hurst390]

Quote
I was not wanting aviation fuel. My compression is around 9.39:1... What would I have to do to convert to PG. Jets are 76 and 34 deg total timing. Thanks....

How do you end up at that compression? With a flat top piston or a dome piston?
If that is a flat top piston I would run it on 93 PG. add a gallon or 2 of R.F. to be safe and for the lead content to help lube the valves. If your jetting is on a 2bbl that's a little richer than I set them up.

[koltveitracing67]

Yes we all see how smart you are

[SRT17]

4BBL 600, FLAT TOP 4 BROW, 70cc head, .040 head gasket, piston .010 in the hole. Can we all stop the bickering.....The board is dead because every body hates the bickering... People come here for help.... Not the DRAMA....Thanks....

[glover11]

Gloverey, you must be a female, you don't seem to mind posting things that are absolutely untrue even when anyone can scroll up and see that your statements are false. Detonation isn't a blown up engine. It is tiny specs on your plugs and next it shows up on your pistons outer edges. Its amazing how dead this forum has been... except the two posts Ive posted on in the tech section. Thank goodness for trolls to up the views on posts on here and at least make it somewhat entertaining to come back! LMAO, I honestly get on here daily to see who your getting your panty's in a wad from. Your usually mad at someone or another...... AND THAT IS A FACT!

[save the racers]

Do a search for Wallace racing calculators They have an fuel mixing cal. to help find the octane you need.Some things you mix with racing fuel does need a blending agent to keep them together.Never had a problem with pump and race separating.

[fastford]

to the original poster, srt17 I think, you didn't say, but if you can run e85, that's the way to go, its 201 a gallon here, I converted our 500 holley my self with a kit bought off ebay for about $175 and it works great, just a thought, and hurst390 hit the nail on the head with AV fuel, we ran it in a blended form years ago in drag cars, but when they changed it , what ever it was, we stopped.

[dereksehi]

I guess I should have never mentioned AV gas as an option didnt realize it would stir this many problems up. That is however what I run.

[Hurst390]

I know of 1 guy 10 years ago(an amateur pilot) that ran it in a drag car(cause he could easily get it).It was in the Carolinas and a little higher elevation than here..lol I don't think he really had any problem with it that I know of but I do know his engine builder cut back on the compression so he could run it..I don't think the octane is calculated the same as pump/race gas.
e-85 is a good idea..take your quick fuel checker and buy it in bulk because from what I'm hearing around here it varies in percentage quite a bit..IIRC 1 guy said he's found it in the mid 70% range. up to high 80's. Otherwise you'll be chasing your ass week to week on jetting..
http://www.quickfueltechnology.com/specialty-parts/echecker---e85-fuel-test-tube.html

[Hurst390]

As far as the guy with 9.8-1 you really don't want to run straight race fuel if that's what your doing..if you don't have enough compression for a given octane your losing power and you'll end up with lead tracks on your plugs and a misfire..
If that is a flat top piston I would run 93 with a couple gallons of RF..If it's a dome and big chamber your gonna need more octane..as a general rule..

[Dirtmod13]

We tried e85 and had issues with the quality also. Went to classic non oxy mixed with e98 to get to a true e85. Way easier. Then e85 got banned so we moved the ethanol content down to 30% 3 gal e98 to 7 gallons of classic car 93 octane and worked great for us. It gives u the boost of the ethanol, raises octane and best part- under 4$ a gallon mixed. We won the last race of the season with this mix.