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Swift 94ul fuel

PilotjohnS

Well Known Member
Simple question for the engine experts, I am planning for a IO-320E2D in my 9a but modified for 9.0 to 1 pistons. Can I run the unleaded Swift 94ul in this engine, or do I need to wait for the 100 octane replacement before switching to unleaded fuel?
 
Engine builder

Simple question for the engine experts, I am planning for a IO-320E2D in my 9a but modified for 9.0 to 1 pistons. Can I run the unleaded Swift 94ul in this engine, or do I need to wait for the 100 octane replacement before switching to unleaded fuel?

I'm not one of the engine experts, but compression is only one element to consider. You also need to know ignition type and timing.
Good choice on the IO-320 for a 9A. I am very happy with 8.5 to 1, Pmags, and a Whirlwind C/S prop on my 1107lb 9A.
 
I have that setup, 200 hrs in 3 yrs, not an expert. I use 50/50 90 octane "REC" mogas NO ethanol fuel with 100LL and so far so good with boroscopes, GRT EIS, Mags at 26 degrees and a carb that will flow 14 gph wide open standard day sea level.

I think if I jumped right into Swift I would set 25 degrees as my only change, for a ratio, probably start with about 30% 100LL. I'm not far from a pump, but have not sought it out. 90 REC at $2.70 is at my corner station and airport 100LL is $3.87. More than the false economy, my oil and plugs stay cleaner, longer. Knock on wood.

My concern is an 8.5:1 O-360 plane I had was placarded 91/96, E-274 TCDS for production 9:1 say 100 octane or 100LL for the H2AD.

I too wonder about Swift94, awaiting a reply from them. Both current 94 and the 102 in testing are mixable with 100LL according to their site FAQs.
 
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Mixing fuel

Rich,
From what i understand of fuels, mixing 50/50 100LL and 90 should bring the octane to right about 97 because it is not a simple average. And seeing your other 9:1 is placard at 100LL sounds like 94UL maybe only good for 8.5:1. Maybe if i do decide to run 9:1 i will stick with 100LL or 100 UL when it becomes available. Thanks for the data.
 
Don't worry about it.

You will be able to get 100LL or a suitable unload 100LL replacement. My bet is it will be G100UL.

I have some inside knowledge that makes me feel confident you will be OK, but not the SWIFT 94 I reckon. ;)
 
Let's remember that lots of folks have been flying on 91 Mogas with around 8.5 to 1 CRs for many years and thousands of hours with no issues. 94 would give you even more freedom with CRs and ignition timing using programmable EIs.
 
Swift 94UL

We have just added Swift 94UL avgas at our airport, Falmouth Airpark. The octane ratings mentioned are by two different methods.

Our 94UL avgas is rated at 94 octane by the motor octane rating method (conservative numbers).

The signs provided to us for our pumps also show a "mogas" rating of 98 octane (r + m/2, the average of research and motor methods of determining octane rating).

Currently our selling price is about 15 cents/gallon less than 100LL.

Check the Swift Fuels web site for more info.

Mitch
RV12 now alcohol free!
 
I have 9:1 pistons in my Superior IO 360 which Superior claims raises the hp from 180 to 185 hp. So not much extra power. Main benefit is it can run leaner than the lower compression engine. Supposedly down to .39 GAL. BSFC.
 
I have 9:1 pistons in my Superior IO 360 which Superior claims raises the hp from 180 to 185 hp. So not much extra power. Main benefit is it can run leaner than the lower compression engine. Supposedly down to .39 GAL. BSFC.

You probably can't run leaner but the thermal efficiency is slightly better with the higher CR.
 
We have just added Swift 94UL avgas at our airport, Falmouth Airpark. The octane ratings mentioned are by two different methods.

Our 94UL avgas is rated at 94 octane by the motor octane rating method (conservative numbers).

The signs provided to us for our pumps also show a "mogas" rating of 98 octane (r + m/2, the average of research and motor methods of determining octane rating).

Currently our selling price is about 15 cents/gallon less than 100LL.

Check the Swift Fuels web site for more info.

Mitch
RV12 now alcohol free!

It's nice to see that unleaded aviation fuel is finally making it to the market and at a better price than 100LL too.

If the Swift fuel is equivalent to 98 octane mogas, most people would require no timing adjustments and could raise their CRs to 9 or over with EIs. That's more great news.

Anyone know what Swift's distribution plans are?
 
Thanks for the links Dan, very interesting. It seems Swift has produced several different fuels. Do you know of any test data on the 94UL product?
 
Dan, those reports are very old and few things should be noted. The FAA have learned a lot since then and the PAFI process is "interesting" to say the least.

Also worthy of note the Swift fuels are not a fungible drop in replacement.

It was hinted in and later proved by Embry Riddle that the Swift fuel was very problematic in cold weather and might not pass in flight relight tests. These test reports were not even generated until 2013, and no i do not have a copy to upload to the internet :)

Also the chemicals required to build these fuels cost way more than the aviation market will pay.

So, I would not hold out on the 2009/10 reports too much.

YMMV
 
Dan, those reports are very old and few things should be noted. The FAA have learned a lot since then and the PAFI process is "interesting" to say the least.

Also worthy of note the Swift fuels are not a fungible drop in replacement.

It was hinted in and later proved by Embry Riddle that the Swift fuel was very problematic in cold weather and might not pass in flight relight tests. These test reports were not even generated until 2013, and no i do not have a copy to upload to the internet :)

Also the chemicals required to build these fuels cost way more than the aviation market will pay.

So, I would not hold out on the 2009/10 reports too much.



YMMV

It seems Swift has ASTM approval for their 94 and 102 fuels and is already distributing them in quite a number of places in the US at prices below 100LL. Perhaps they've addressed the issues you mentioned in the years since the report? Relight problems on a warm SI engine in flight? Really? Seems to me if it started a cold engine on the ground, it would be no problem on a warm engine in flight.

https://swiftfuels.com/ul94-map/
 
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I spoke with a Swift representative at Oshkosh 2016 and he told me the "biomass" based fuel was discontinued and future Swift products would be petroleum based. If I understood what he told me, that program had outside investors who decided not to continue funding the project. Our local RV builders group hosted a video conference with the Swift people when the biomass fuel was being developed. It sounded great, with direct production costs about "25% of 100LL", and performance meeting or exceeding 100LL in all areas tested. Anyway, I just hope we end up with an acceptable replacement without a price penalty.
 
Dan, those reports are very old and few things should be noted.

Like your relationship with one of the other fuel players?

Hey, I'm all for competition. It's good for consumers, notably me. I'm also all for capitalism, R&D, and the rewards thereof. It would be great to hold a patent on the next generation av fuel. And for sure, I personally like your guy very much.

That said, if you don't have data to share, talk is cheap, in particular when the talk just knocks the other team.

BTW, Swift fuel aside, there is a huge mass of Lycoming 100LL operating data in those reports. It's not easy to find, and very valuable. From the Shoe On The Other Foot Department, I seem to recall how a certain group of guys poked Lycoming for years, quite rightly, about their position on LOP operation. They had data to show, while Lycoming wouldn't support their position with data.

I'm aware of a few oddities in the FAA reports, but I'll take it none the less.
 
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Simple question for the engine experts, I am planning for a IO-320E2D in my 9a but modified for 9.0 to 1 pistons. Can I run the unleaded Swift 94ul in this engine, or do I need to wait for the 100 octane replacement before switching to unleaded fuel?

To go back to the question. I don't have a first hand answer for it, as we have not gotten our hands on any of this fuel or fuels just yet. We do have an IO-360 with 9:1 and Slick mags, just like you would fine in the certified field. You should not be producing quite as much B. hp. as this set-up. We do run 92-93 Mow-gas with no "E" strate out of the pump at the local station. We will run a 50:50% mix of 100LL to this 92-93 no E from time to time as well as strait 100 LL when on the road away from home base. We have run down to 82-83 Mow-gas with 15% "E", but we try to keep the power down to under 70% at all times other than take off. We have had no problems with the middle octane UL auto fuel and it dose well with no problems. The only thing we do is cut our ignition timing down from the recommended 25* BTDC to 22.5*. This seams to keep the engine running just a little cooler and still run very well. We have done this with big sixes in the past as well. I can't say for sure but my impression is that as long as you play it cool and have a good monitoring system you will be fine with this new bang juice. Hope this helps. Yours, R.E.A. III #80888
 
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In the January issue of Sport Aviation, Steve Ells' reports excellent experience with the Swift 94UL. He recorded engine data from flights with both fuels, same RPM and conditions, and says no difference in CHTs or EGTs. At one point, he had 100LL in one tank and 94UL in the other, and showed no changes in engine temps when switching back and forth. He even had others analyze his engine data to double check his observations. All in all, it's a pretty impressive test and result.
 
I just contacted Sebring Airport KSEF, to inquire about the availability of UL94 as they are on the Swift list.
They do have it available, but at the same price as 100LL & Mogas. $4.25/gl.
No savings here.

I can get 100LL in the area for $3.40-3.80/gl.

The article I read earlier said it would be priced mid-way between 100LL & Mogas. Same price :(
 
So on the other end, how will I know if the octane is not high enough for my engine?

I assume you have quality individual CHT indication.

As you lean into detonation, the CHTs will climb fairly rapidly. Given heavy detonation, the numbers will spin up like the digits on a filling station pump.
 
I just contacted Sebring Airport KSEF, to inquire about the availability of UL94 as they are on the Swift list.
They do have it available, but at the same price as 100LL & Mogas. $4.25/gl.
No savings here.

I can get 100LL in the area for $3.40-3.80/gl.

The article I read earlier said it would be priced mid-way between 100LL & Mogas. Same price :(

Dan, I was at Sebring last week attending the EXPO, there were lots of guys at Swift display, but I did not stop. Was too busy looking at all the neat LSA airplanes.

Sound like Swift will be an approved fuel when 100LL goes away. we won't save money but at least will be able to continue flying.
 
Only way

I assume you have quality individual CHT indication.

As you lean into detonation, the CHTs will climb fairly rapidly. Given heavy detonation, the numbers will spin up like the digits on a filling station pump.

So the only concern with low octane fuel is detonation? So as long as my engine is not detonating i am good to use the lower octane fuel?
Does lower octane means less LOP?
 
So the only concern with low octane fuel is detonation? So as long as my engine is not detonating i am good to use the lower octane fuel?

Precisely. Octane rating is a measure of resistance to detonation.

Do remember there are pro-detonation factors in addition to octane rating. Higher cylinder head temperature, higher intake air temperature, and to a small extent, higher oil temperature all increase detonation risk. Point is, a fuel that does not allow detonation in a cool engine on a cool day may still allow detonation given hot conditions.

Does lower octane means less LOP?

No. Detonation risk is at maximum between 100 ROP and 50 LOP, with a peak roughly in the middle of the range. Go farther LOP and detonation risk is lessened.
 
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More Unleaded Avgas Suppliers

Looks like GAMI's G100UL fuel is still undergoing testing/ certification. Perhaps we'll have another player in the unleaded avgas field soon. http://www.gami.com/g100ul/news.php

Shell has 82UL for low CR engines ASTM approved now. Are they selling in anywhere in North America yet? http://www.shell.com/business-customers/aviation/aviation-fuel/avgas.html

Maybe soon there will be some decent supply so people can do cross country flying on unleaded fuels.

Possibly time for us to start looking at developing targeted closed loop software for our aviation EFI systems.:)
 
Correction

I contacted Swift last week about some technical info on their fuels. I wanted to correct info in a previous post that the UL102 fuel is being commercially distributed at this time. That's incorrect. Only the UL94 is for sale at the moment. The UL102 is still undergoing testing under the FAA PAFI program.
 
UL94

I got the lead out......Early real world report. 9A, O-320, Hartzell, Carb, Pmags, LOP almost always after initial climb.

UL94 is for sale just east of the home drome. $3/gallon, only 3 tanks of experience, so far. I run a mix of UL94 and mogas in my left tank and all mogas in my right tank. In my setup, UL94 acts just like 100LL at spring and winter temps. I'll watch it closely as temps increase to make sure it behaves similarly. Clearish in color, no real odor, clean plugs, nice price. No noticeable diff in temps or performance observed between 100LL/UL94/Mogas. YMMV

That said, the only issue I have had is with winter mogas, on a warm spring day. I had pneumatic lock on a fast turn, hot start, . This was easily managed with using the mixture knob on start.

If 94UL really has the same vapor pressure profile as 100LL, I'll be lead free all summer.
 
Thanks for the real world report. The engineer said 94UL is essentially the same formulation as 100LL without the lead so vapor pressure should be close to the same.

Hope Swift can widen the distribution area this year.

Good price!
 
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I got the lead out......Early real world report. 9A, O-320, Hartzell, Carb, Pmags, LOP almost always after initial climb.

UL94 is for sale just east of the home drome. $3/gallon, only 3 tanks of experience, so far. I run a mix of UL94 and mogas in my left tank and all mogas in my right tank. In my setup, UL94 acts just like 100LL at spring and winter temps. I'll watch it closely as temps increase to make sure it behaves similarly. Clearish in color, no real odor, clean plugs, nice price. No noticeable diff in temps or performance observed between 100LL/UL94/Mogas. YMMV

That said, the only issue I have had is with winter mogas, on a warm spring day. I had pneumatic lock on a fast turn, hot start, . This was easily managed with using the mixture knob on start.

If 94UL really has the same vapor pressure profile as 100LL, I'll be lead free all summer.

Reviving an old thread, this is the only post I could find with someone running 94UL on a carb engine with dual P-mags.

Pete if you see this, or if anyone else has the same setup, is it still going well and which timing curve are you running on the P-mags? The A curve with the jumper, default B curve (no jumper), or a modified B-curve (and if so with what timing advance and other settings)? Thanks!
 
Pete if you see this, or if anyone else has the same setup, is it still going well and which timing curve are you running on the P-mags? The A curve with the jumper, default B curve (no jumper), or a modified B-curve (and if so with what timing advance and other settings)? Thanks!


All is well - I run mostly 92 Mogas(boat gas) here in Minnesota. UL94 runs much like 100LL in my engine when I use it. I run an advanced B-curve fall/winter/spring and the A-curve in the summer to help manage temps.

A-curve is always the safer option to start with. My B-curve is modified, but I don't recall the exact settings. The B-curve helps run LOP more effectively, but raises temps.

Hope that helps.
 
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SNIP
Pete if you see this, or if anyone else has the same setup, is it still going well and which timing curve are you running on the P-mags? The A curve with the jumper, default B curve (no jumper), or a modified B-curve (and if so with what timing advance and other settings)? Thanks!

I recommend running with the jumper in, regardless of the fuel used. Jumper in provides up to 9 degrees of timing advance - and all my reading tells me there is nothing to be gained with more advance other than higher CHTs.

I’m sure there is an exception or two (racing) where more advance does something, but for 99.9% of RVs jumper in is the way to go.

Carl
 
I recommend running with the jumper in, regardless of the fuel used. Jumper in provides up to 9 degrees of timing advance - and all my reading tells me there is nothing to be gained with more advance other than higher CHTs.

I’m sure there is an exception or two (racing) where more advance does something, but for 99.9% of RVs jumper in is the way to go.

Carl

Actually racing is one place where you don't need any extra spark advance. You will be running best power mixture (AFR=12.5:1) or even richer to manage temps. Keeping the timing in the 20--25 BTDC range works fine, and gives lower CHT, especially toward the 20 end of that range. Retarding the timing a little bit reduces CHT, and that allows you to lean toward best power mixture rather than over-rich to cool.
 
I recommend running with the jumper in, regardless of the fuel used. Jumper in provides up to 9 degrees of timing advance - and all my reading tells me there is nothing to be gained with more advance other than higher CHTs.

I’m sure there is an exception or two (racing) where more advance does something, but for 99.9% of RVs jumper in is the way to go.

Carl

I have an advance table plus a knob that gives -4/+5 from the table. I don't think that I have gone any higher than 35/36. It really depends upon mixture. leaner mixtures need more advance. The benefit comes from matching advance with the MAP and mixture to achieve optimum power output

As Steve said, max power comes ROP with low advances. Optimum timing does make a difference there, but that is going to be in the lower to mid 20's. Higher at best power and less when richer than that.

Larry
 
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