DS1 Flex Fuel vs Uni-Corn Flex Fuel option

[DrBoost]

I am looking for feedback and advice for a true flex fuel option on my RS3 and I am looking for info here because FB sucks and I am old school and still prefer forums!!

I have a 2019 RS3 with some basic mods Uni S1+ tune and S2 TCU tune along with midpipes, CTS 4" turbo inlet and intake pipe running though the stock air box and even that factory paper element. I also have a P3 gauge with a ECA installed With as little as my car has done it does run pretty well. Last year after completing the mods It went 10.88@128 on a draggy pull running 78% E85 and I have made a few 10.90-11.0 passes all at 128mph. On S1+ 93 the car runs 11.20s @122 all these runs are last fall in good air. TBH I am perfectly happy with the level of performance I get from the car on E85 and would like to run the car on a flex fuel program all the time without having to re-flash the ECU or manually change fuel maps or tunes.

I am not sure how the DS1 flex fuel works? Do you just have the ability to manually change the fuel map to account for the change in ethanol content or does the ECU automatically scale the fuel MAP and timing based on ethanol content? I went looking and I did not find out much about how it actually works? I know you have to wire a ECA sensor into the ECU pin with a 3k resistor which is not a big deal but curious as to how well it works just driving.

I mostly just drive this car and have other hot rods that are considerably faster than my RS3 especially in a drag race and are also true flex fuel cars. I only drive the RS3 in the warmer months and while I have 5 E85 gas stations within just a couple mile of my house there are none in areas I frequently travel to with the car. So to take the car to our summer home I have to swap back to 93 and then swap back to E when I got home, kinda of a PIA.

I have not done much with the car this year other than drive it and left it on 93 all year. Other than hurting a Hellcat and Corvette owners feelings at a couple of stop light encounters I have not raced the car at all this year. I am getting ready to put it away for the winter and swapped the factory tune back in to take it in to the dealer for the recall and a coolant leak it developed with only 11k miles on the car. I am considering making the change to the DS1 over the winter but want to be able to keep the same performance I have with the Uni S1+ E85 tune and the ability to just put what ever gas I can get at the pump without having to mess with fuel maps or re flashing the ECU? I also want to keep my P3 gauge and ECA which is another issue with the DS1 I don't think you can split the signal?

Another issue I have with the DS1 is it seems to have a step learning curve. While I have a lot of experience with tuning and datalogging I just don't want to get into learning another software and computer platform when I have two other cars running two different systems already. I really just drive my RS3 and not looking to mod it much more than it is. If I were plannign to do the motor and upgrade the turbo fuel system etc I would go all in on the DS1 but I really want something that is PnP so to speak.

So since I wont see the car till April maybe I should wait for the Uni-corn Flex fuel option that has been several years in the making.......lol!!!

[Hollingsworth]

Since your car will be out of commission until April, the no brainer decision is to just wait to see what the Unitronic Flex fuel will be. Sounds like it is very very close to being released, and hopefully we'll see it before Xmas. Once it's out, compare the two, see what is best for you, and then have confidence you made the right decision. To me. this seems to be the easy, no brainer way, and is exactly what I am doing myself

[mtwallace85]

DS1 is true flex fuel so once it’s setup, you just put what you want in the tank and drive. You have map switching included for things like stock power, valet mode, full fan, and lockout. Concerning the learning curve, unless you’re custom tuning the car yourself you don’t really need to mess with the software. I don’t think you’ll be able to use the P3 gauge, not that you’d want or need it at that point. You’ll probably lose a tiny amount of performance going to DS1 but it’s definitely safer than Unitronic.

[DrBoost]

Thanks for the feedback that is what I was looking to hear. I think sacrificing a little bit of performance to be able to have true flex fuel is worthy trade off at least for me. IMO running the car on E85 is just safer all around. While I dont have any plans to custom tune the car myself its nice having the option. Is the datalogging pretty decent from some of the screen shoots I have seen it is?

I am waiting till spring but this is like the 3rd maybe 4th year its almost ready to be released by X-mas, I am starting think I have a better chance of seeing Santa with flying reindeer b4 seeing Unitronic Flex Fuel. If there any black Friday deals this year on the DS1 I may jump on it.

[nate.co]

I've got a 2019 RS3 and have been running a custom stage 2 DS1 flex fuel setup for about 20k miles now. Tuned APR 1+ at 50K, switched to Uni stage 2 at 60K and then DS1 at 80K. Currently 101K miles and going strong.

You need to leave the module plugged into the OBD port, at least need to keep it in there when you're changing fuels as it does the live mapping calculations. I just leave it in all the time, and watch the ethanol content change on the "power" gauge on the dash. K&G here is usually about E64, but sometimes up to E70. Nice to know it's remapping and I've definitely noticed more power when I go to the race fuel stop and get E75 (Hill Petroleum in metro Denver).

You can't keep the P3 gauge plugged in at the same time. Can't have two devices on the OBD at once.

As far as day to day, you don't have to do anything. Just fill up with gas and go. If you want, you can connect to wifi running on the module and control the tune, see gauges, etc, but you can also just drive the car and forget about it

You can use a BTRes display (https://betterthan.shop/), but the display module is for the S6 and is huge in the RS3 (I tried making a mockup and couldn't find a good place to put it). I'm waiting for the "mini" version to ship and am going to try and put a small display in the vent, similar to the P3.

Can't comment on the Uni flex fuel obviously, but the DS1 is really nice. I did opt for a custom tune so it's calibrated to this altitude and my setup (Unitronic intercooler, catted mid & downpipe, IE intake and elbow, upgraded injectors). Shout out to Bluewater Performance (https://bwperformance.com/) as a fantastic shop in the area.

So far, no issues at all. Power is smooth and just sings above 4k. No pops and bangs and very minimal "burbles" -- I had the Uni stage 2 and it was too much pops & bangs for my taste. Not sure if you can add them back in or what, but I prefer to not attract too much attention -- as is the downpipe and midpipes make for enough attention.

Anyway, hope that helps

[mtwallace85]

Thanks for the feedback that is what I was looking to hear. I think sacrificing a little bit of performance to be able to have true flex fuel is worthy trade off at least for me. IMO running the car on E85 is just safer all around. While I dont have any plans to custom tune the car myself its nice having the option. Is the datalogging pretty decent from some of the screen shoots I have seen it is?

I am waiting till spring but this is like the 3rd maybe 4th year its almost ready to be released by X-mas, I am starting think I have a better chance of seeing Santa with flying reindeer b4 seeing Unitronic Flex Fuel. If there any black Friday deals this year on the DS1 I may jump on it.

The data logging is one of the things that’s nice about the DS1. You simply connect to the DS1 via a Wi-Fi connection using your phone or a laptop and then you can view everything in the browser. There’s a couple screens with a several gauges, then there’s a third screen for a different style gauge that shows everything from the first 2 gauge pages, there’s a map switching page, etc. Then there’s a real time logging page that gives you a visual of the engine data as well as record, stop, reset, and download buttons. Just flip to the page and it starts logging automatically and hit the download button when you want to save the log.

Now, if you want to make it even easier, you can get a bTres. They offer the product with or without a mountable screen. With this product the car is constantly being logged and the logs are saved every 2.5 minutes and downloaded to a usb or uploaded automatically to the cloud where they can be viewed using the bTres log viewer. The car will also do dyno and pull logs automatically. A dyno log happens when you’re in 3rd, 4th, or 5th and you go 100% throttle from under 2500rpms to over 6000rpms. A pull log happens when you go over 80% throttle and stops when you fall below 80%.

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[S3DUDE]

DS1 is true flex fuel so once it’s setup, you just put what you want in the tank and drive. You have map switching included for things like stock power, valet mode, full fan, and lockout. Concerning the learning curve, unless you’re custom tuning the car yourself you don’t really need to mess with the software. I don’t think you’ll be able to use the P3 gauge, not that you’d want or need it at that point. You’ll probably lose a tiny amount of performance going to DS1 but it’s definitely safer than Unitronic.

Not to contradict you or to doubt you but how is the DS1 safer if Unitronic hasn't released their product yet? is it something that DS1 has that Unitronic don't plan to have? like ie : a double fail safe?. Like I said, I am not trying to doubt or contradict, I am currently on the same situation as the OP and I am trying to learn more on the two systems. I also run Unitronic maps but there is only one gas station nearby and it is almost imposible to leave the city without switching to 91oct.

To the OP. My opinion you sould be waiting for Unitronic to release their product. Just like username Hollingworth said on post #2, specially because you don't need to drive it on E-85 now. You also have plenty of rides and can afford just to wait.

[mtwallace85]

Not to contradict you or to doubt you but how is the DS1 safer if Unitronic hasn't released their product yet? is it something that DS1 has that Unitronic don't plan to have? like ie : a double fail safe?. Like I said, I am not trying to doubt or contradict, I am currently on the same situation as the OP and I am trying to learn more on the two systems. I also run Unitronic maps but there is only one gas station nearby and it is almost imposible to leave the city without switching to 91oct.

To the OP. My opinion you sould be waiting for Unitronic to release their product. Just like username Hollingworth said on post #2, specially because you don't need to drive it on E-85 now. You also have plenty of rides and can afford just to wait.

I said that because of 2 reasons:

The first is the tuning isn’t as aggressive; the tunes were specifically made to be more on the safe side rather than being the fastest tune out there.

The second is DS1 has a zero failure rate whereas I’ve seen 3 people in the last week share their blown motor from a stage 2 e85 Unitronic tune. While that isn’t necessarily common, it doesn’t hold a candle to the failure rate of the DS1 in my opinion.

The flex fuel implementation doesn’t really have anything to do with it, it’s the tune specifically.

[DrBoost]

When you start modifying stuff to make 50-100% more power than it was originally designed for stuff breaks. Some of these stock motor S2 E85 cars are pushing into the 9s from what Ive seen and to do that your gonna be on the edge and when your there shit happens!

I do like that the DS1 is an open book and can tune it. I don't like that Uni is very secretive about what is in their tune and I suspect they put a lot of timing in their E85 tune which can be dangerous.

When I first got the car I was asking basic questions about how they tune the car and how the factory fuel strategy is set up. I just wanted to know basic stuff like if it was using a linear WB02 and fueling off speed density vs MAF. I also wanted to know how the ECU calculates MAP, it uses two MAP sensors and the boost reading on the P3 gauge is something that is calculated and you can read it several different ways. Stuff like that is why I dont want to tackle tuning on my own and want something that is more PnP. Ans I have a lot of experience in tuning standalone systems and making a lot of HP with stuff like the MS3pro, and Holley and have tuned many older FAST, Accel DFI and even BS3 systems.

That being said Uni has had a lot of time to bring this to market and have gotten a really good look at what the competition is already doing and I would really like to see what they come up with before jumping in on the DS1. I will be running flex fuel next year either way.

[ZTTRS]

Ds1 is also still relatively new to this platform, so it doesnt have the sample size of customers that Unitronic has. To compare failure rates at this point is a very incomplete and un fair picture.

[Alex D]

Ds1 is also still relatively new to this platform, so it doesnt have the sample size of customers that Unitronic has. To compare failure rates at this point is a very incomplete and un fair picture.

I believe a few of the respected DS1 tuners had mentioned that the timing advance was very aggressive on the unitronic. . There are a few tuners that have managed to get a image of the unitronic tune so they are able to replicate the tune on the DS1.

[8STTRS]

While none of us have experienced the Unitronic version of their flex fuel, suffice to say that their map will most likely culminate on their current E85 maps. They really don't have any reason to otherwise. They're likely going to bridge their current 93/E10 files to meet with their current E85 files and use a flex fuel sensor and application specific to their needs. The apprehension comes from where certain folks in the industry have taken a hard look at their files and understands what was done and why. Now, while there may be a fundamental disagreement about philosophies regarding which way they'd like to skin a cat, suffice to say, there are strong opinions on the matter and unsurprisingly, they defend their stance using whatever tools are needed to sway the opinion of the masses.

I personally chose to go with a custom tune(r). I find it completely mind boggling that anyone would use a canned tune on a car with forced induction beyond a simple reflash and a couple of supporting mods. I come from the GM/Ford world where canned tunes are largely villainized and basically every car receives a custom tune. While I will of course pay attention to what Unitronic brings out if/when they ever decide to release their flex fuel support, I don't think I'd convert back to their files after working with Darin. Even if my car isn't as fast as a Unitronic tuned car, I much prefer the time, attention, care, and specific feedback he gives about my car and how he's addressing it, along with making sure the car is behaving how I'd like it to. If Unitronic offered these maps as a baseline to start data logging so that they can do some tweaks for your file, then again, you have my attention. But they don't openly discuss support like that despite whispers about it happening for certain folks who are pushing the envelope.

Also, a lot of us are using certain products that are only supported via custom tuning at the moment, such as 1300cc port injectors, dual fuel pumps and the TC series of turbos. While Unitronic is giving folks the TTE777 file for TC800XT owners, there is no direct support for it. Now that the TC800XT is no more and the TC870XT has taken its place, I can only assume that the TTE855 file will be used in those applications. At that rate, again, I'd rather have a custom file.

[slammin86]

While none of us have experienced the Unitronic version of their flex fuel, suffice to say that their map will most likely culminate on their current E85 maps. They really don't have any reason to otherwise. They're likely going to bridge their current 93/E10 files to meet with their current E85 files and use a flex fuel sensor and application specific to their needs. The apprehension comes from where certain folks in the industry have taken a hard look at their files and understands what was done and why. Now, while there may be a fundamental disagreement about philosophies regarding which way they'd like to skin a cat, suffice to say, there are strong opinions on the matter and unsurprisingly, they defend their stance using whatever tools are needed to sway the opinion of the masses.

I personally chose to go with a custom tune(r). I find it completely mind boggling that anyone would use a canned tune on a car with forced induction beyond a simple reflash and a couple of supporting mods. I come from the GM/Ford world where canned tunes are largely villainized and basically every car receives a custom tune. While I will of course pay attention to what Unitronic brings out if/when they ever decide to release their flex fuel support, I don't think I'd convert back to their files after working with Darin. Even if my car isn't as fast as a Unitronic tuned car, I much prefer the time, attention, care, and specific feedback he gives about my car and how he's addressing it, along with making sure the car is behaving how I'd like it to. If Unitronic offered these maps as a baseline to start data logging so that they can do some tweaks for your file, then again, you have my attention. But they don't openly discuss support like that despite whispers about it happening for certain folks who are pushing the envelope.

Also, a lot of us are using certain products that are only supported via custom tuning at the moment, such as 1300cc port injectors, dual fuel pumps and the TC series of turbos. While Unitronic is giving folks the TTE777 file for TC800XT owners, there is no direct support for it. Now that the TC800XT is no more and the TC870XT has taken its place, I can only assume that the TTE855 file will be used in those applications. At that rate, again, I'd rather have a custom file.

To be fair, the ecu on these cars is much more advanced than most of the offerings from Gm or Ford. As someone who has been tuning gm ls vehicles for over 13 years, I am totally fine runing a canned tune in my rs3.

[8STTRS]

To be fair, the ecu on these cars is much more advanced than most of the offerings from Gm or Ford. As someone who has been tuning gm ls vehicles for over 13 years, I am totally fine runing a canned tune in my rs3.

I'll concede about LS ECUs but, I think the LTx ECUs are a fair bit trickier. I see a ton of LS tuners try to tune LTx cars the same way they tune LS cars and end up with subpar results. Nonetheless, the fact that the ECU is much more advanced on these cars, makes me even more leery of running a canned tune at higher power levels.

[DrBoost]

Using a Uni tune my Rs3 went from 122mph S1+93 to 128mph S1+E85 from what I can tell at the same boost level. IMO That is an aggressive timing curve making that happen.

U can only pick up 6 mph with better fuel if u throw more timing and/or boost at it.

IME more boost is typically safer than more timing. While its hard to detonate a motor on E85 really bad things happen really fast when u do

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[lemonvr6]

I'll concede about LS ECUs but, I think the LTx ECUs are a fair bit trickier. I see a ton of LS tuners try to tune LTx cars the same way they tune LS cars and end up with subpar results. Nonetheless, the fact that the ECU is much more advanced on these cars, makes me even more leery of running a canned tune at higher power levels.

If the targets and safeguards are looking for the right numbers where’s the risk?

[8STTRS]

If the targets and safeguards are looking for the right numbers where’s the risk?

There's a couple of if's in there. Depending on who you speak to, those if's are quite important. Either way, this specificity of how different companies approach their tuning and safeguards is bound to open up a massive can of worms. I think it would behoove any would-be customer to ask as many questions as possible--especially to those who are not selling the product.

[brobst]

The tune is probably fine. Its the constant pushing and pulls back to back that causes issues. Most people dont have issues commuting to work for example

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