FF Fuel for Auto-X

[syrarch04]

I just picked up a '77 Zink Z-10C for Auto-X duty, but the car hasn't been raced in eight years. I've obviously got some work ahead of me getting it ready for the spring, first of which will be replacing the fuel system. The car currently has a small (probably 1.5 gallon) aluminum fuel cell in the right sidepod, and the foam was a known problem before it was put up. Also, the previous owner ran 93 octane auto fuel, but I've seen a lot (most?) folks on here run 110 AV fuel. Here's my series of noobie questions:

- Where the heck can I get foam for an oddball little cell? Pegasus only seems to have larger size pieces.

- How much power is there typically to gain moving from 93 to 110?

- Assuming I could source the 110AV, what would I need to adapt the engine to running that? I'm assuming the carb settings would need to be adjusted to run a different octane, correct? As little as I know about FFs, I know even less about the dark art of adjusting carbs.

Thanks guys!

Dustin

[formulasuper]

I just picked up a '77 Zink Z-10C for Auto-X duty, but the car hasn't been raced in eight years. I've obviously got some work ahead of me getting it ready for the spring, first of which will be replacing the fuel system. The car currently has a small (probably 1.5 gallon) aluminum fuel cell in the right sidepod, and the foam was a known problem before it was put up. Also, the previous owner ran 93 octane auto fuel, but I've seen a lot (most?) folks on here run 110 AV fuel. Here's my series of noobie questions:

- Where the heck can I get foam for an oddball little cell? Pegasus only seems to have larger size pieces.

- How much power is there typically to gain moving from 93 to 110?

- Assuming I could source the 110AV, what would I need to adapt the engine to running that? I'm assuming the carb settings would need to be adjusted to run a different octane, correct? As little as I know about FFs, I know even less about the dark art of adjusting carbs.

Thanks guys!

Dustin

Summit has multiple sizes of fuel cell foam, plus you can cut it to size & shape. I don't believe you'll notice any power difference with avgas & probably no change to the engine settings, but others on this forum can give better info on that.

[veefan]

Check out e-bay, "Fuel Cell Foam". Most foam can be easily cut to fit the cell. For $18. including shipping it's hard to beat.
http://cgi.ebay.com/ebaymotors/Summi...Q5fAccessories



You can get AV Gas at most smaller airports, some will not pump it into containers.

You can also check out your local Sunoco gas stations, some carry race fuels.

http://www.sunoco.navisite.com/

http://sunocoinc.com/site/Consumer/RaceFuels/

[Dick R.]

Dustin,

So far (18 years autocrossing this car) I have ONLY used major brand street premium.

The carb is an off the shelf from Pegasus unit running the same jets Ivey installed which presumeably were for AV gas since that is what he recommends.

I have no problems of any sort with street gas and when I ran Pro Solo's with side by side drag race starts, my car accelerated the same as any other FF in the other lane assuming our reaction times were close. As you say, there is a good chance they all had AV or race gas.

The foam blocks are available from ATL in NJ. Cut to a size small enough to fit through your opening. Be careful regarding jamming it against the pickup opening

Supposedly the new foam handles E10 levels of alcohol OK.

My engine is being refreshed now and I will be talking seriously with the builder about changing to AV gas or Race gas (probably unleaded 100 Octane). The engine has no need for the high octane by the way.

Another trick for autocrossing is to use street heat range plugs. Nice cheap Champions or NGK's are what I've used. That way you can change them more often as they get black from warmup time.

Dick
CM 85
85 VD

[Jim Garry]

Dustin,

IMO, you're fine running the 93 octane pump gas. Engine builders have stated that there is something to be gained using the higher octane fuel with an engine tuned for it. But you told me you'll mostly be doing local events with perhaps a larger event or two if they're not a long tow. With that in mind, save yourself money and effort and use the pump gas.

A very long time FF autocrosser, Dick R, has always used 93 and has nothing but positive things to say about his experience.

EDIT: Hah! Dick beat me to it. See, I told you. :-)

[Dick R.]

I got interrupted and cut short the previous post. Regarding E10 street gas it probably is a good idea to drain or pump it out of the cell for the winter since Eagle Fuel Cells (my new cell came from them) says current auto gas is not good for the cell for long term exposure.

I also replace any gas in the cell which is more than a month or two old, especially if it was "winter blend" because that is lower on power to some degree and more likely to "vapor lock" from the heat between runs if your bodywork is tight around the carb.

Plus E10 may absorb water and separate. If you never run leaded gas in the cell you can simply take the unused gas and put it in a car. Mine ends up in a lawn tractor or the tow vehicle.

Also, you do not need foam in the cell for autocrossing. Fuel slosh might be an issue but from a rules and safety perspective the foam isn't necessary.

Dick

[syrarch04]

Thanks for the quick responses! I was looking at the thread in the Club Ford section about fuel cell storage (link below) and the discussion that started regarding the stability, or lack thereof, of pump gas, which is what got me thinking I should try to use AV. It's good to hear I don't have to though. What are you running Jim?

http://www.apexspeed.com/forums/showthread.php?t=42947

[Jim Garry]

When I have higher octane fuel I run it. But I'm not shy about putting 93 in when I run out.

[Steve Demeter]

I would recommend nothing but AvGas. 100LL.

It is made for airplanes, not the trash they sell you for the street, has stabilizers and no alcohol in it.

The Fuel Safe guys at the IMIS told me today to store the cells empty for the winter.

[Scootin159]

+1 on the suggestion to run hotter plugs. Obviously a different type of motor, but in the FMod I run plugs two steps hotter than the road race guys, as it makes it real hard to foul a plug. The NGK plugs I use are ~$.50/each, so I can swap them every event - don't need to - but it prevents any issues.

If you do decide to go with the race fuel, there's a Sunoco in Cicero/Bridgeport with race fuel in the back. It's also used fairly often during the summer with the ESTA traffic, so it's fairly fresh in the tank. It is more than double the price of 93 pump gas, but the cost really isn't prohibitive when you figure you'll likely use less than three gallons at an event. It's more just the inconvenience of not being able to buy it at the corner store.

[EYERACE]

Higher octane fuel is not about getting more power from that type of fuel. Higher octane fuel is necessary if the compression ratio is high to avoid predetonation. A legal 1600 FF motor is not a high compression engine. So 110 octane is a waste of money and will run a hotter temp. Lower octane fuel actually is a source of more power versus higher octane fuel. The lower the octane fuel you can use without pinging the more power the engine will produce. So understand that the higher power output, when one is using 110 octane in the high compression engine, is due to the higher compression ratio and not the higher octane fuel. The higher octane was needed to avoid pinging.

Lots of local small airports have self-serve pumps these days for their 100 octane low-lead AV gas. When the pump asks for a tail number - just make one up.

[rmccown]

Lots of local small airports have self-serve pumps these days for their 100 octane low-lead AV gas. When the pump asks for a tail number - just make one up.

Local airport here has me on file, I used my car's serial number. N472VD. I should put tail numbers on the rear bodywork, just to be 'legal' and all.

[EYERACE]

yes, but that must mean your car has "tailfins"

[jdp526]

I am running VP Racing fuel mixed apprx 50/50 with pump gas. Their VP110 and C12 fuels are leaded which should help lubricate valve seats. According to VP guy, their racing fuels are much more stable than pump gas and will last for several months without having to add any gas stabilizers. And they said it would be fine to mix pump gas with it for lower compression engines.

I buy the fuel from a local racing shop. VP has primary distributors around the country so racing shops may be carrying it in your locale.

http://www.vpracingfuels.com/

[kayakanimal]

I have access to fuel WITHOUT Ethanol in it. Would that help...hurt...make NO difference?

[syrarch04]

Good question. I have been using standard pump 93, so E10 now unfortunately, but a station nearby has started offering 91 without Ethanol. I am assuming it would be best to stick with the 93, but does anyone disagree?

[mwizard]

Good question. I have been using standard pump 93, so E10 now unfortunately, but a station nearby has started offering 91 without Ethanol. I am assuming it would be best to stick with the 93, but does anyone disagree?

My head builder, Porter, advised me to use at least 1/2 leaded to protect the valves. I have been mixing half 110 with 87. The local airport fuel guy won't sell me aviation fuel. I will try another airport someday.
Mark