Hehehe having fun pushing things a little bit with this E30 mix :)

Red line is current E30 tune, blue line was latest 92 octane gas tune. Still making adjustments, but thought I would share the progress. Will be going to an E50 blend next. Wanted to get dialed in gradually as I up the mix.

Not sayin' VD graphs are an accurate representation of actual horsepower, but definitely shows the improvements I am making...

https://cimg4.ibsrv.net/gimg/www.rx8...b19bca959b.jpg

Looks really promising Slash . What's the butt dyno saying ?

Butt Dyno says why didn't I do this sooner?!? Shoulda listened to yomom!

So the adjustments I made were to lean it out a bit from the gas tune. On gas my AFR was in the deep 10's due to the timing issues I was seeing. I got that tune to where I was seeing best power with no timing pulled, tho I'm sure it could still be improved.

On the E30 I've been running closer to 10.8. Got that spike at the end and a bit of timing pulled. Aside from the spike you can't see the AFR change because it's lower than what the stock gauge reads but I can see it on the ProSport. Will put in an E50 blend on my way home today, but snow is in the forecast so not sure when I'll get to log again...

Now I've got a tank of E50 but haven't had a chance to do any testing yet so I'm researching E85... Found this particularly interesting...

"High ethanol blends have been shown to permit higher CR operation. Caton et al. [10] showed that for E85 blends, the maximum brake torque (MBT) spark timing could be maintained up to a CR of about 13.5, whereas MBT could not be maintained for gasoline and E10 past a CR of 9.0 in a modified CFR octane rating engine. Nakata et al. [11] showed at a CR of 13.0, MBT timing was knock-constrained for E0, E10, and E20, but not knock-constrained for E50 and E100 at the tested conditions. Stein et al. [12] evaluated a dual fuel system, where gasoline was delivered through a PFI injector as the primary engine fuel, and E85 was delivered as the secondary engine fuel as-needed to prevent knock.

It was found that under turbocharged conditions with a 12.0 CR configuration, the maximum amount of E85 required to prevent knock at peak load was less than 60%, which is effectively about E50."

https://bioenergykdf.net/system/file...ds_Szybist.pdf

This chart from the doc sums it up. RG=regular gas, HO=high octane.


https://cimg4.ibsrv.net/gimg/www.rx8...7a5767405.jpeg

So primarys and secondarys on gas for milage and p2 on a 5 gallon e85 tank in the boot?

Sounds I ntresting.

Sure, but my takeaway was why go full E85 when E50 is practically just as effective for knock resistance? E50 also has a higher stoich ratio (11.57) which means less fuel delivery requirements and better MPG. I'm excited to get logging and experimenting :)

E85 would still bet better due to the extra cooling effect from the higher volume of it you would need to use .

Yeah, they had some results on the cooling effects as well, which did indicate E85 had highe cooling properties than E50 leading to increased airflow. But the difference between E85 and E50 was less than the difference between E50 and HO/RG (which makes sense as 50% vs 35% ethanol content difference, but the effect did not seem to be linear). So my question would be would the difference in cooling effect between E85 and E50 be worth the difference in fuel consumption between the two? Unfortunately, I didn't see any comparison in specific fuel consumption between E85 and E50, unless I missed it?

I have no idea how much the difference will be or if it is significant or not . I just think e85 would be the one to go for if you want to push the envelope . If it's just safety factor at current boost levels you are after ....what you are doing will probably suffice.

Safety factor for now, pushing the envelope will likely be the next step as I can't seem to stop. The bad weather is likely keeping me from blowing things up right now, as I was already contemplating cranking back up to 17psi :lol:

E 50 sounds intresting at 10.8 :1 then you can swap from gas to e50 with little concern. Maybe have a low boost setting for gas and a high one for e50.

I agree. I'm keeping my gas tune on the Cobb for a quick reflash for gas. I'll see how far I can push E50 and then decide next steps. My wife will be getting me a pair of ID725s for my bday in Jan :)

You may want to ask her for an extra pair of underpants if you're pushing past 17psi.

:lol: I can't go too much past without doing something with the MAF like a voltage divider. I was pegging it at 4.99V at 17psi previously...

no. You have an awesome station

So had a little excitement today... Was doing some more testing with E50 and had a coolant line rupture. I shut the car off immediately and coasted to the side. As I'm looking in the bay for the leak I see a little flame pop up. I grabbed the extinguisher and put it out. Got towed home and cleaned her up. Back in the garage I found the busted hose. No fuel leaks so I'm not sure where the flame came from and I don't see any burns anywhere. Replaced the hose and she runs fine. Might be taking a break from the big boost game for a bit. When I saw that flame all I could think was the car is gone, but so far turned out ok. So... Always carry a fire extinguisher!!!

Oh, and when I got home my alcohol premix was at the door :)

https://cimg4.ibsrv.net/gimg/www.rx8...486d78a41.jpeg


https://cimg5.ibsrv.net/gimg/www.rx8...337ed25af.jpeg


https://cimg5.ibsrv.net/gimg/www.rx8...e2afb08e8.jpeg


https://cimg6.ibsrv.net/gimg/www.rx8...b4a1f6373.jpeg


https://cimg8.ibsrv.net/gimg/www.rx8...f6eefcfef.jpeg

The latest changes are looking good anyway :)



https://cimg2.ibsrv.net/gimg/www.rx8...263cf89fe.jpeg

Scary man, after some scares I always carry an extinguisher now. My guess is that you surely have a fuel leak. Flames don't just come from no where.

Maybe fuel was leaking at higher pressure. But I am also wondering if a rubber hose or something near the exhaust manifold got really hot and ignited. At any rate it is in the garage and cleaned up so I will be tearing it down to investigate. Just glad I didn't lose it!

Good save!
I carry a fire extinguisher in all my cars.
That dry chem is very corrosive don't let it sit on there.

.

Thanks man :) As soon as I got it towed back to the house I washed it all down. Nasty stuff got everywhere but saved the car for sure!

So far I have not been able to find what caused the flame. Nothing charred or singed that I can find. It popped up on the fender side of the LIM, almost like it was coming up from the exhaust manifold itself. The APV looks fine from what I can see. I'll have to dig into it deeper. I think she's officially in the garage for the winter...

:icon_tup::icon_tup::icon_tup::icon_tup::icon_tup:

Glad you saved it man !


Great results ...looks like you are running it quite lean ?

E50 baby! Been doing a lot of reading and it seems most people are targeting 12:1 to 12.5:1 on E85 (gasoline AFR). The AKI (R+M/2) difference between E50 and E85 is negligible, 95.6 vs 95.8. Might even be able to push it a bit further. No sign of timing getting pulled either. Was actually planning on adding a degree or two back in when this hose burst mid-log. I had the file already to go on the Cobb :lol: