SKUSA to Test Unleaded Fuel with X30

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Some of you know that I’m an advocate for moving towards unleaded fuel for two stroke karting in the US. As much as I love the stuff, including the smell, It’s hard to ignore the neurotoxicity of lead\TEL, especially when young developing brains are involved…

For those outside the USA, yes leaded fuel is still being used here. It of course allows for higher octane, but also the lead acts as a great dry lubricant for the internals of a two stroke.

Announced by SKUSA today. They are testing unleaded fuels for the X30. If one can overlook the fact that everywhere else in the world runs unleaded,

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Attention #racers heading to the #skusaprotour — we would like to formally invite you to participate in an exclusive environmental fuel test being held
Monday May 24, 2021 from 7:00 AM to 12:00 PM

Location: @utahmotorsportscampus

On May 24th, we will have an independent test crew coming in to gather real data comparing leaded and unleaded fuel (VP MS98 Fuel and Aspen Sport 98 octane).

We will be providing 30 new X30 engines for this test in total, for each participating driver. Every motor will be inspected before the test. We will distribute all new motors in the morning to be mounted on the karts. We are requiring every participant that receives a new engine to bring a completely clean fuel tank to avoid cross-contamination.

We will provide both fuels being tested, the oil, and the new motor for each driver. The driver will be required to provide a clean kart/chassis, and a new unused or clean fuel tank, line, and pump. We will simulate a small race day. Any used or new tires are acceptable for the test.

In an ever-changing world to move to cleaner and greener methods, this will be the future of fuel worldwide – and this will be an exclusive opportunity to collect data before this new eco-friendly fuel is released. All participants will be sent home with fuel to test at their home track with their team as well as all exclusive data from the dyno and from the test day.
We will offer all the X30s (and kits) that were used in the test day to be able to be taken home for $1500. For drivers who don’t want to keep the motor we will give them $200 for the few hours of their time they helped with this test.

To qualify to take home the motor for $1500, you have to be available from 7 am until 12 pm on Monday, follow the rules, and be able to mount the motor and fuel tank on the chassis yourself in the morning, with your own tools. (We are accepting all drivers 12 years and up.) We will have the garages open to work in for the test so teams can pack up their trailers after the race.

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If it were East of the Mississippi I would’ve signed up already. It’s long past time to go to an unleaded fuel.

If your track doesn’t specify fuel use 93 AKI / 98 RON from the first pump at a busy station next to a freeway so you know it’s fresh. Start 15 minutes rich on both jets and lean to best EGT from there.

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Now try unleaded in the SSE 175 engines!

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Wow, I had no idea leaded was still used.

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Yep I was pretty stunned when I got to a kart track here and saw that… that was 2006!

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James Mc Mahon wrote:

" It’s hard to ignore the neurotoxicity of lead\TEL,especially when young developing brains are involved…"

I like this quote!

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I still remember having tears in my eyes,while I was racing…and it wasn’t because
of disappointment,it was because of all sort of mixed fuels,like tolueen etc…
It’s good that these times are history!

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Any of you guys have an update / feedback on this fuel? It has been used in the FWT last week.

I see on their site that they have two different fuels for karting.

Aspen R (102 RON octane)
Aspen + (98 RON octane)

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It was used at supernats too. Some slight carb adjustments were needed. I don’t know much about it though.

@XanderClements KC happy hour show did a segment talking about it after Vegas. I’ll find the video

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Anyone know why SKUSA has backtracked and changed the spec fuel back to leaded Sunoco 112?

Disappointing.

Rather odd after acknowledging the harmful effects of leaded fuel in a press release: SKUSA To Officially Adopt Aspen Sport As New Spec Racing Fuel In An Effort To Promote Safer And Cleaner Solutions For Racers And The Environment.

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I personally have not run the Aspen fuel, but the grumbling around the paddock was the Aspen fuel did awful things to the top end of the engines. Could be legit… could be old men yelling at the sky…

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I’ve only ever used 98 unleaded straight from the pump. No additive other than 2 stroke oil. Leaded isn’t even available here, why they would go back to leaded is beyond me.

Sounds like some folks with power being sticks in the mud.

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We have run Aspen for 3 years now in Sweden on all classes. No problems besides the carbon reeds on X30 cracks

It’s a better and more consistent fuel, leaves basically no deposits at all

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Slightly off topic, but how does one get no deposits at all on the piston crown? Is that to do with the chemistry of the fuel, how it interacts with the added oil, the oil/fuel ratio, running (too) rich, and/or ignition advance? It’s the complete opposite to my pistons (running Elf Race 102 and Elf 909 at 4.5%) on both a CR125 and 175 SS.

As an aside, many of us run Elf Race 102 in Australia for shifter engines since losing access to AvGas LL, or alternatively just unleaded 98 (like BP Ultimate). Other than for issues with the CR125 (and having to run about 5 jets higher than with AvGas), everyone seems happy and without significant top end problems. I believe KZ2 under Karting Australia rules run unleaded Panta (but I have no experience with that fuel).

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Speaking as a mechanic for a team that really supported Aspen fuel and got punched in the mouth by it later:

Aspen had trouble holding a consistent specification, and it was tough to get technical information out of them. They didn’t have a full datasheet available for the new fuel they introduced right before the SuperNationals in 2022. The '22 SuperNationals fuel was also notable because it only narrowly met the 98 RON specification minimum; previous Aspen Sport fuel exceeded it. The SuperNationals was very cold that year, lows less than 5 C, highs less than 15 C. In its favor, the Aspen evaporated really cleanly - spills of a couple ounces went right away - and it aggressively cleaned piston and head deposits.

The IAME SSE 175 was always marginal on 98 RON fuel. MRC and IAME USA never recommended any pump gas for it - even eastern 93 AKI fuel which is often 100+ RON. Combine the cold weather (high air density) with fuel that suddenly stopped evaporating well when the airflow was fastest, and we had fifteen engine failures in one week.

I suspect SKUSA will continue to test unleaded alternatives, but they needed something else and they needed something people would have minimal trouble with, so Sunoco 112 was selected for now. If SKUSA were to ask me what fuel to try next, I’d recommend the VP 101 unleaded I’ve been running this season.

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Good question. We run slightly richer with Aspen + 98ron, could maybe have something to do with it. Carries the deposits out.

But egt, plug and exhaust manifold color is spot on. This is with 4% motul 2t on my kz

On my 100cc it leaves slight deposits after 3h, but nothing serious. 6% of motul 2t

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How on earth Can itbe thishard to move away from leaded fuel, i Can not recall when it was last possible to buy it here In northen Europe.
Sweden have been using Aspen+ for two years now, no reports of inconsistency, or reports of bad things happening, yes you need to/adjustdifferently then with whatever you use now.

At a lot of races In Europe we havets buy pump gas and use that, and it rarely gives any issues.

I simply dont get why it needs to made up to this Big an issue.

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Charles, given your team (read Billy M) were such big supporters of the 175 SSE, and hence have some intimate knowledge of the engine development/rollout, why on earth didn’t SKUSA just land on the base Euro version with the electric starter and the 36 mm Dellorto carb?

As you may recall I run the Euro version here in Australia (both sprint and long/road circuit). My latest piston has 15 hours on it and the bottom end just under 30 hours (one more race this weekend and it will go in for its first bottom end re-build). Plus it runs on just unleaded 98, no problems. The engine just keeps going. I did try using Elf Race 102 but was struggling with some carb and/or ignition advance issues - just seemed so rich. The IMAE guys in Italy (via the Australian distributor) said don’t bother, the engine is perfectly fine on, and designed for, unleaded 98 (plus that in their view the Elf 102 ran “cold”).

Given these running times (15 hours plus on the piston and 30 hours plus on the bottom end), no problems running unleaded 98, not to mention the massive bonus of an electric start, I just don’t get what was ever achieved with the redesigned SSE. Had the base 175 SS version been adopted by SKUSA instead, there may have been a much better take up of the engine and a real alternative to the CR125 other than KZ (nothing against KZ, but whichever way you cut it, they are more expensive to run and less tolerant than a 175 SS in race trim, and no electric start).

Thoughts?

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I can’t speak for everywhere in the states as I know there are differences depending on where you’re at, but here we can’t even get pump gas high enough octane to run a kart engine well. I can and have run Sunoco 260gtx unleaded 98 aki but it’s notably more expensive than the Sunoco standard 110 that’s available at the same place. Some of the difference is the 110 is available in bulk where the 98 is only available in pails. Leaded race fuel is very prevalent in the US for circle track racing (and probably drag racing) and until there’s a large push to eradicate the lead I don’t see a change really happening. Back in my youth methanol was a common used fuel in the 4 cycles of the era, thankfully that’s not the case in sprint racing anymore but I do still come across it a lot in the dirt oval stuff and man is that stuff nasty. Methanol is still used a ton in circle track and drag racing, not sure how much it is used outside the US but like leaded race fuel is still very prevalent here.

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Isn’t Sunoco 112, the SKUSA spec fuel, only available in 5 gallon pails? As far as I can tell 260GTX is the same price, +/- $10, as Sunoco 112.

If 112 is allowed, I would imagine most people are running that despite the cost difference over high octane leaded pump gas. Walking through the paddock at west coast events, Sunoco 112 is quite clearly the fuel of choice. I am not sure the money argument holds much weight. People are going to run the most powerful fuel they can get their hands on despite what cost difference there may be.

Kids should not be exposed to this stuff. Whatever cost difference there may be is clearly worth it to prevent unnecessary exposure to something that is clearly toxic.