Race gas mixture stock?

[Defense]

I've searched throughout the forums, but I can't find much about running race gas without a tune and at what mixture. Would it be ok to run a 50/50 mix of 93 octane and race gas on a stock m3? What about other mixtures? I've seen one guy mention "a friend" that ran 50/50 blend of 91/race gas with fantastic quarter mile/dyno outcomes because the engine boosted the timing automatically. Please advise.

[mike@x-ph.com]

You can run gas fuel without any tune. That being said, it will be a waste of money if the car is not tuned for it.

[Defense]

Thanks for the advice!

[///M.Tonee]

Originally Posted by mike@x-ph.com

You can run gas fuel without any tune. That being said, it will be a waste of money if the car is not tuned for it.

+1
well said...car has to be tune to take advantage of it or it's just a waste of money

[MaynardZed]

Overall yes, you would need a tune to add power from just race gas, but I would recommend adding some race gas if you are doing a track day. Just to guard against pulling timing. I usually run 50/50 mix of 91/100 octane for a track day.

[8600RPM]

Lots of misunderstanding . Last 3 generations of M cars have been unable to hit max tI ming targets on 93 octane unless in cold weather and not consistently. I logged a ton of data with my e9w and it targeted 32 degrees timing up top and it too 95 octane mix to hit this target consistently.

I've logged my f80 for a,month or so now and again , stock car pulls timing in any warm weather with repeated hard pulls. It also shifts boost curve left and raises boost in mid range. With 100 octane it will allow full timing even with repeated pulls on stock tune.

So in a cool weather, single pull, it won't make more power for the f80 (it did make more on e9x) but it will allow you to continue making full power as it will prevent timing being pulled on 93. I haven't logged mixes in midie to see where benefit hits a ceiling. My guess on stock tune its in 96 octane range but I'll need to log.

Mike aren't you a tuning person? I'm surprised you would make such a blanket incorrect statement on a very easily measurable topic

[mike@x-ph.com]

Originally Posted by MaynardZed

Overall yes, you would need a tune to add power from just race gas, but I would recommend adding some race gas if you are doing a track day. Just to guard against pulling timing. I usually run 50/50 mix of 91/100 octane for a track day.

+1 it is never a bad idea to raise your octane if you have a track day

Originally Posted by 8600RPM

Lots of misunderstanding . Last 3 generations of M cars have been unable to hit max tI ming targets on 93 octane unless in cold weather and not consistently. I logged a ton of data with my e9w and it targeted 32 degrees timing up top and it too 95 octane mix to hit this target consistently.

I've logged my f80 for a,month or so now and again , stock car pulls timing in any warm weather with repeated hard pulls. It also shifts boost curve left and raises boost in mid range. With 100 octane it will allow full timing even with repeated pulls on stock tune.

So in a cool weather, single pull, it won't make more power for the f80 (it did make more on e9x) but it will allow you to continue making full power as it will prevent timing being pulled on 93. I haven't logged mixes in midie to see where benefit hits a ceiling. My guess on stock tune its in 96 octane range but I'll need to log.

Mike aren't you a tuning person? I'm surprised you would make such a blanket incorrect statement on a very easily measurable topic

Are you saying fully stock M4 cannot hit stock boost?
Havent seen it happening in any log . Please share your logs.
Would also be very interesting if you have temps as well. You should not be getting any timing pulls unless temps are really high.

[8600RPM]

What do you this k is special about a track? Yet you say it's a good idea there. As I said depending g on conditions and how many pulls or how aggressive you drive the timing wonT hit full 12 to 14 degrees up top with 91 or 93 . If weather is cool and you don't do high rpm pulls or drive aggressively, it will do fine on 93.

However to say it's not tuned for it, in a complex target based ecu is just thinking that's out of touch with a modern m car.

Higher octane mixes will prevent knock as aggressive driving and heat factor in and subsequently will allow full timing to be hit consistently and thus power. It won't effect weather peak boost is hit necessarily however it will shift peak boost left to midrange and taper above 6500. This is more IAT dependent however.

Also with a tune, it's again to allow full timing to be hit and to build in safety as more boost is applied. It doesn't directly effect boost level.

You sell a jb4 don't you? Surprised you do T go log for yourself to see the differing effects.

[mike@x-ph.com]

Originally Posted by 8600RPM

What do you this k is special about a track? Yet you say it's a good idea there. As I said depending g on conditions and how many pulls or how aggressive you drive the timing wonT hit full 12 to 14 degrees up top with 91 or 93 . If weather is cool and you don't do high rpm pulls or drive aggressively, it will do fine on 93.

However to say it's not tuned for it, in a complex target based ecu is just thinking that's out of touch with a modern m car.

Higher octane mixes will prevent knock as aggressive driving and heat factor in and subsequently will allow full timing to be hit consistently and thus power. It won't effect weather peak boost is hit necessarily however it will shift peak boost left to midrange and taper above 6500. This is more IAT dependent however.

Also with a tune, it's again to allow full timing to be hit and to build in safety as more boost is applied. It doesn't directly effect boost level.

You sell a jb4 don't you? Surprised you do T go log for yourself to see the differing effects.

Are you not reading any of my replies ?

On a track you are pushing your car to its limit multiple times within couple hours, higher octane is always a great idea to prevent knocks as you and I mentioned in our posts.

On daily driving if you do a quick pull or 2, adding race gas will not be as helpful because car will do just fine and will hit target boost + target ignition without any problem.

Remember we are discussing the effects with a fully stock car which means no tune.

Im confused to what you are arguing about ?
Unless you disagree with the 2 statements in red, we are in complete agreement to the benefits of race gas on a stock car

[Defense]

I just ran the car back to back to back 1000ft racing with 93 octane gas stock. It was 98 degrees F. If I can gain a 10th or two from buying a few gallons of race gas I will. Even as a veteran car guy, Im just very confused with the whole ecu/tuning/timing stuff.

[AlpineE92M3]

All the octane raring is the resistance to detonation. Aside from a tune for race gas, you probably won't see any power gains, just a better resistance to detonation. It won't hurt ur car by adding race gas, but you won't maximize it's use unless it's tuned for it.

[mike@x-ph.com]

Originally Posted by Defense

Even as a veteran car guy, Im just very confused with the whole ecu/tuning/timing stuff.

When temps are high, ECU will reduce performance to keep your engine safe.

[Mike@N54Tuning.com]

Originally Posted by 8600RPM

Higher octane mixes will prevent knock as aggressive driving and heat factor in and subsequently will allow full timing to be hit consistently and thus power. It won't effect weather peak boost is hit necessarily however it will shift peak boost left to midrange and taper above 6500. This is more IAT dependent however.

This is very well said..

Mike

[8600RPM]

Anyone who has logged data on modern bmws of at least the last w generations, especially m cars know that bmw rides these cars very close to many limits and uses the more advanced education to ride the line of things like timing and ecu. The e92 m3 literally rode knock sensor and logging could show you that there was constant knock events detected and adjusted with the past ionic control system to allow advanced timing as possible. That was bone stock with 93 octane in mild aggressive driving.

I've noticed similar behavior with the M4 and I believe the n54 and n55 engine in that the car stock rides line max timing and aggressive 12.5 afr. Partly DI can be more agrease but the e92 m3 wasn't di.

You better believe bmw and others push these to limit to take advantage of better performance and fuel efficiency while relying heavily on the modern ecu to adjust when conditions aren't right.

So yes, in hoT weather or with any decent aggressive driving, you very well may not hit max timing bone stock without a 95 or 96 mix. If you do 1 random hard pull and otherwise cruise slowly, you won't need it. However many of us drive the puss out of our cars on the street so for those folks, a race gas mix is,helpful especially in summer.

Don't take my word. Go log data


QUOTE=mike@x-ph.com;18223663]Are you not reading any of my replies ?

On a track you are pushing your car to its limit multiple times within couple hours, higher octane is always a great idea to prevent knocks as you and I mentioned in our posts.

On daily driving if you do a quick pull or 2, adding race gas will not be as helpful because car will do just fine and will hit target boost + target ignition without any problem.

Remember we are discussing the effects with a fully stock car which means no tune.

Im confused to what you are arguing about ?
Unless you disagree with the 2 statements in red, we are in complete agreement to the benefits of race gas on a stock car[/QUOTE]

[8600RPM]

Also I've found no matter what furl used, you can't prevent the boost table from sgifting at IATS of 110 or so and above. This is where met would be really the solution or if the flash tunes progress to moify boost tables under high iat conditions and create a race fuel map.