[ab987]

Originally Posted by studio54

Yes thanks, but I am talking about AFR targets in the V5 40 BIN. (See screenshot)

No matters if you run ethanol or race fuel, it will not change the targets.

Those targets looks close to what 100 octane race gas targets could be.

https://github.com/dmacpro91/BMW-XDF...A0S.xdf#L10623

Right, and look at the calculation. It's almost certainly actually some lambda value that is conveniently multiplied by 14.7 in the XDF (gas stoich) for some reason or another. It should really just be lambda imo, unless there's another reason I'm overlooking.

Sure, lambda will be similar across all fuel types, but actual AFR (not whatever calculation is in the XDF) will change accordingly. 14.7AFR on e40 would be terrifyingly lean under any meaningful load. I hope this makes sense

[studio54]

Originally Posted by ab987

https://github.com/dmacpro91/BMW-XDF...A0S.xdf#L10623

Right, and look at the calculation. It's almost certainly actually some lambda value that is conveniently multiplied by 14.7 in the XDF (gas stoich) for some reason or another. It should really just be lambda imo, unless there's another reason I'm overlooking.

Sure, lambda will be similar across all fuel types, but actual AFR (not whatever calculation is in the XDF) will change accordingly. 14.7AFR on e40 would be terrifyingly lean under any meaningful load. I hope this makes sense

I am maybe wrong, but I think our O2 sensor won't measure AFR but only lambda value. So from fuel tables DME will convert AFR targets to lambda, 14.7 for example to lambda 1 at idle or low load, and will target a lambda of 1. So, no matters if you run ethanol or fuel, the mixture will be target to match the lambda targetted value.

I mean a lambda target of 1 is fine, no matters if you run gasoline or ethanol.

EDIT: I guess the calculation on the XDF is for tuning convenience, to display values in AFR in the table

[Sgop335]

studion54, ab987, the AFR table in tunerpro is scaled for gasoline. There is a fuel scalar table that puts more or less fuel depending on the stoichometric.

For example, one can target afr=12.5 in tuner pro which is actually lambda=0.85 (for any fuel)

But to get lamda=0.85, one has to inject more fuel for e85 than gasoline due to the difference in stoicho. This is where the fuel scalar tables help. Technically, the short term fuel trims stft will try to cover this difference but if the load is high they can max out. The proper way to do it is put higher scalar values in the fuel scalar table to compensate for the stoicho.

Hence running a racefuel is different than ethanol blend if the stoichometric ratios are different.

[ab987]

Originally Posted by studio54

I am maybe wrong, but I think our O2 sensor won't measure AFR but only lambda value. So from fuel tables DME will convert AFR targets to lambda, 14.7 for example to lambda 1 at idle or low load, and will target a lambda of 1. So, no matters if you run ethanol or fuel, the mixture will be target to match the lambda targetted value.

I mean a lambda target of 1 is fine, no matters if you run gasoline or ethanol.

EDIT: I guess the calculation on the XDF is for tuning convenience, to display values in AFR in the table

Right, but fuel scalars are the difference between the tunes. Running E20 on a 93 tune is okay because trims will make up for the difference to hit the target lambda, but when you run mixtures as high as E40 on a race gas tune, the trims won't keep up and you'll probably run lean.

What I'm trying to point out here is that this is the ONLY platform I've ever seen that irresponsibly treats lambda as AFR. For an unsuspecting tuner, they may tune an ethanol car to run way too rich despite giving normal ethanol lambda values, and for users, they may see that AFR targets are the same so that must mean they can interchangeably run fuels with different energy densities on the same tune.

[studio54]

Originally Posted by ab987

Right, but fuel scalars are the difference between the tunes. Running E20 on a 93 tune is okay because trims will make up for the difference to hit the target lambda, but when you run mixtures as high as E40 on a race gas tune, the trims won't keep up and you'll probably run lean.

What I'm trying to point out here is that this is the ONLY platform I've ever seen that irresponsibly treats lambda as AFR. For an unsuspecting tuner, they may tune an ethanol car to run way too rich despite giving normal ethanol lambda values, and for users, they may see that AFR targets are the same so that must mean they can interchangeably run fuels with different energy densities on the same tune.

I meant the opposite, running race gas 100oct on V5 E40 tune, even with a little bit modified fuel scalar, trims should follow (and of course HPFP) since it will inject way less fuel than it will with ethanol to reach the lambda target.

Yep, I think it's because of the way the XDF is written, you can remove the *14.7 from the equation and probably get a lambda tables instead of these AFR calculated with stoich gasoline.

[ab987]

Originally Posted by studio54

I meant the opposite, running race gas 100oct on V5 E40 tune, even with a little bit modified fuel scalar, trims should follow (and of course HPFP) since it will inject way less fuel than it will with ethanol to reach the lambda target.

Yep, I think it's because of the way the XDF is written, you can remove the *14.7 from the equation and probably get a lambda tables instead of these AFR calculated with stoich gasoline.

If you got the trims right, I don't see why it wouldn't work. I just don't really know why you'd pay double the price :P

I believe they are absolutely lambda tables, and somebody incorrectly decided it was equivalent to AFR and added that multiplication factor. Again, don't know who or why they did that.

[studio54]

Originally Posted by ab987

If you got the trims right, I don't see why it wouldn't work. I just don't really know why you'd pay double the price :P

I believe they are absolutely lambda tables, and somebody incorrectly decided it was equivalent to AFR and added that multiplication factor. Again, don't know who or why they did that.

Hehe I always wanted to test the famous V5 E40, but unfortunately I have no access to E85 in my place, and no race gas aswell It was just hypothetic and for my curiousity, and when my curiousity kicks, it ends up in a thread jacking, sorry for OP...

I ran E30 with 96% liquid bioethanol for fireplaces I bought at the DIY store, but I am not confident with it, it was just to reduce my CO emissions for the test. (And it's not cheap !)

However I believe that if you blend like half a tank (20-25 liters) of 91oct with two strong octane boosters bottle, maybe you can reach close to race gas octane rating but not sure. Probably safer to stick with a recent Stage 2+ with 95oct map if I want to do a one shot blend with octane booster for fun

[ab987]

Originally Posted by studio54

Hehe I always wanted to test the famous V5 E40, but unfortunately I have no access to E85 in my place, and no race gas aswell It was just hypothetic and for my curiousity, and when my curiousity kicks, it ends up in a thread jacking, sorry for OP...

I ran E30 with 96% liquid bioethanol for fireplaces I bought at the DIY store, but I am not confident with it, it was just to reduce my CO emissions for the test. (And it's not cheap !)

However I believe that if you blend like half a tank (20-25 liters) of 91oct with two strong octane boosters bottle, maybe you can reach close to race gas octane rating but not sure. Probably safer to stick with a recent Stage 2+ with 95oct map if I want to do a one shot blend with octane booster for fun

Ahh that makes more sense. I would stick to 95oct personally there may be other reasons the e40 (~95oct) is more potent vs 95oct, like ethanol's cooling effects

[syntax]

The problem with V5 e40 is not everyone wants desensitized knock tables on an all around ots map and not everyone will run e40 on the stock lpfp. By the time you get a lpfp upgrade you might as well just get a custom tune with a tmap. Desensitized knock is not as much of a problem when the tune is made for your car specifically.

[syntax]

I got 393whp on virtual dyno with v10 stage 2+ in 3rd gear on 93 with a bottle of octane booster on my xi. I added it and it fixed my timing corrections. I stopped the pull at 6000. The e50 map on v10 is probably crazy.

[iqraceworks]

Originally Posted by syntax

The problem with V5 e40 is not everyone wants desensitized knock tables on an all around ots map and not everyone will run e40 on the stock lpfp. By the time you get a lpfp upgrade you might as well just get a custom tune with a tmap. Desensitized knock is not as much of a problem when the tune is made for your car specifically.

I spent quite a bit of time talking to Ken at Wedge (guy who made the V5 E40 map). He said that although the knock tables are desensitized a little, it's not to the point where it's going to hurt anything..it's just enough to keep false knock issues from popping up. Tons and tons of guys run that V5 E40 tune with no issues. Yes, I agree that it's a good idea to do a stage 2 LPFP upgrade...but you can do that yourself for the price of a $125 Walbro 450 pump and a couple of fittings. Going to a custom tune is another $400+ and weeks of logging runs, getting revisions, and logging more runs. For guys with stock turbos....it's not worth the hassle.

When I had stock turbos I loved that V5 E40 stage 2+ map...it was nuts!! I ran it for a long time, did tons of logs, and never had any issues. Honestly....if it was "dangerous", MHD wouldn't even still have it as an option. The reason they kept it is because it rocks!! 👍

[ab987]

Originally Posted by syntax

I got 393whp on virtual dyno with v10 stage 2+ in 3rd gear on 93 with a bottle of octane booster on my xi. I added it and it fixed my timing corrections. I stopped the pull at 6000. The e50 map on v10 is probably crazy.

Shame that the Motiv FlexFuel kit has shortcomings and isn't supported by Ken anymore, I have E50 in the tank now but am stuck on the V9 flex map, otherwise I'd try both and let you know how they compare

[syntax]

Originally Posted by ab987

Shame that the Motiv FlexFuel kit has shortcomings and isn't supported by Ken anymore, I have E50 in the tank now but am stuck on the V9 flex map, otherwise I'd try both and let you know how they compare

Tomorrow I'll probably test v10 e30 as I never used e85 before. Will do minor pulls starting out to test timing corrections and stock lpfp psi if it's good I'll send it and show a picture of my virtual dyno results

[ab987]

Originally Posted by syntax

Tomorrow I'll probably test v10 e30 as I never used e85 before. Will do minor pulls starting out to test timing corrections and stock lpfp psi if it's good I'll send it and show a picture of my virtual dyno results

Definitely make sure LPFP is good on 93 before trying ethanol, and most pumps this time of year are somewhere in the E65 range (at least in the south) so it would be a good idea to measure content first

[cruizin01]

Originally Posted by ab987

Shame that the Motiv FlexFuel kit has shortcomings and isn't supported by Ken anymore, I have E50 in the tank now but am stuck on the V9 flex map, otherwise I'd try both and let you know how they compare

What the issues with Motiv kit?

[ab987]

Originally Posted by cruizin01

What the issues with Motiv kit?

As I understand it from Ken, boost cannot be different based on ethanol content and instead timing is the only thing that can change, which is limiting. The way the unit is designed also can lead to reporting 100% ethanol content if there is voltage feedback, which would at the very least leave you stranded if not cause some damage. Reflex is the method of choice nowadays.

For that reason he generally doesn't do MHD flex fuel for custom tunes and doesn't even support it for OTS maps anymore by the looks of it.

[syntax]

Originally Posted by ab987

As I understand it from Ken, boost cannot be different based on ethanol content and instead timing is the only thing that can change, which is limiting. The way the unit is designed also can lead to reporting 100% ethanol content if there is voltage feedback, which would at the very least leave you stranded if not cause some damage. Reflex is the method of choice nowadays.

For that reason he generally doesn't do MHD flex fuel for custom tunes and doesn't even support it for OTS maps anymore by the looks of it.

I just did a pull with flex fuel that tested at e72. I did mhd v10 e30. It's making well over 400 wheelon virtual dyno. I probably had one of the shittiest ethanol mixes ever on stock lpfp. No timing corrections across 3 pulls, except on one of the 3 log pulls where I shifted into 4th and kept logging into 4th gear, cylinder 4 went to -6 and then down to -2.5 after a brief moment. The lpfp and rail pressure are fine. Timing climbed as usual with no dips but it dipped for a brief moment to 0 from around 8 at 5700 rpm then went back up. Never did ethanol before though. Car feels maybe slightly faster than when I do a quarter tank of 93 with a bottle of octane booster.

[syntax]

I will gladly do the flex fuel conversion with an upgraded lpfp if it isn't difficult to install or expensive. I don't think the gambling of ethanol content with no sensor or flex fuel module will be good for the stock pump and shit in the long term. I will also go with a custom tune.

[ab987]

Originally Posted by syntax

I will gladly do the flex fuel conversion with an upgraded lpfp if it isn't difficult to install or expensive. I don't think the gambling of ethanol content with no sensor or flex fuel module will be good for the stock pump and shit in the long term. I will also go with a custom tune.

Do keep in mind that reflex is the proper way to go. MHD is not pushing any new flex fuel maps as far as I can tell so you'd be limited to V9. If you are still interested I will sell my motiv kit probably in the next month or so, I can't use it with my hybrids

[syntax]

Here's a nice roll race in my 335xi against a 400whp audi s4 with upgraded Ko4 Turbos. My car is fbo with mhd v10 e30. His exhaust has a little leak, thats the supercharger sound Lol. Sorry for the bad video quality https://streamable.com/a1wows

[R3dLeader]

Originally Posted by syntax

Here's a nice roll race in my 335xi against a 400whp audi s4 with upgraded Ko4 Turbos. My car is fbo with mhd v10 e30. His exhaust has a little leak, thats the supercharger sound Lol. Sorry for the bad video quality https://streamable.com/a1wows

Supercharger sounds with upgraded K04 turbos? Something isn't adding up lol. One or the other unless it's a Volvo!

[iqraceworks]

Originally Posted by syntax

Here's a nice roll race in my 335xi against a 400whp audi s4 with upgraded Ko4 Turbos. My car is fbo with mhd v10 e30. His exhaust has a little leak, thats the supercharger sound Lol. Sorry for the bad video quality https://streamable.com/a1wows

Man....that is one crappy video