E85 On Stock 2017+ Cars Specifically

[Yoshoobaroo]

Originally Posted by DarkSunrise

Yeah I think that's right. It seems like 91 vs. 93 makes a pretty big difference on these engines. When I used to live on the east coast, my car ran great on 93. IAM was solidly at 1.00 (when street-driving) with the different OFT OTS tunes I've used - stage 1, stage 2 catless, stage 2 catted.



But when I moved to the west coast, IAM dropped to 0.66 on stage 1 OTS on 91.



Now that I switched to e85, IAM is back to 1.00. With a stock header, it feels like it pulls about the same from 4000 to redline as my old stage 2 UEL catless setup on 93.

Agreed, E85 with stock header feels the same as 93 on a UEL catless header.

[bfrank1972]

Originally Posted by 86TOYO2k17

From what I’ve read, seen dynos, and many others attest. E85 is additive maybe with slight diminishing returns though, and should make a solid difference. How much you personally can feel say 10whp idk.
A few things to note about your situation specifically.

One as you said 93-E85 is smaller jump then from 91 but still a big jump none the less.

You mention you are on a stage 2+ E85 tune. The OTS tune is more conservative tune especially with E85 bcs the ethanol % varies so much needs to cover a wide % range to be safe. without flex fuel and custom tune you won’t really be tapping into the true power of E85, also those tunes are designed to be used with UEL or EL in doing so won’t fully maximize either one.

Lastly I know those tunes are set to have IAM start at .7 and go up if no knock is detected. Is your IAM going up to and then staying at 1 on both 93 and E85 tunes? If it stays at 1 on 93 but is constantly dropping to say .8 on E85 it’s going to pull timing and drop power a little on E85 making the difference less. I think flex fuel and custom tune could really make a difference.

Yeah I dunno - I sort of think the same way. Adding a header in our cars is all about improving VE, especially in the middle of the curve where the dip is. E85 is about increasing the knock threshold on an engine, and longer cylinder burn, which I think *should* have noticable benefits on top of a good header. Maybe the tune is too conservative or maybe it's a case of me just expecting too much - I mean anything we do to these cars outside of FI is not going to make them rocketships. I'll get one of those dyno apps and do a few before and after runs to see what really happens.

Oh BTW IAM is 1 and stays there.

Sent from my SM-G965U using Tapatalk

[ermax]

Originally Posted by Yoshoobaroo

Exactly. Gains from a header and e85 are not additive. A header gets your most of the way there, so adding E85 didn't add that much.

I’m not sure I follow. E85 has a higher octane and allows for way more timing advance. A header doesn’t mean that suddenly more timing isn’t going to help. Maybe people aren’t wowed because there isn’t a bump in SPL out the back of the car in E85.

[bfrank1972]

Originally Posted by ermax

I’m not sure I follow. E85 has a higher octane and allows for way more timing advance. A header doesn’t mean that suddenly more timing isn’t going to help. Maybe people aren’t wowed because there isn’t a bump in SPL out the back of the car in E85.

Hah that's not the case with me. I'm 47. I like my cars on the quieter side

[ermax]

Originally Posted by bfrank1972

Hah that's not the case with me. I'm 47. I like my cars on the quieter side

I'm not implying people do things because they want it to be louder but that people tend to associate louder with faster. You may want your car to be quiet but that doesn't mean that if something made it louder it wouldn't trick you into feeling like it got faster too. I've seem people make changes to their car and say how much faster it feels and it turns out it actually got slower. The butt dyno is very inaccurate is all I'm getting at.

[bfrank1972]

Originally Posted by ermax

I'm not implying people do things because they want it to be louder but that people tend to associate louder with faster. You may want your car to be quiet but that doesn't mean that if something made it louder it wouldn't trick you into feeling like it got faster too. I've seem people make changes to their car and say how much faster it feels and it turns out it actually got slower. The butt dyno is very inaccurate is all I'm getting at.

Yeah I know the syndrome you're talking about - I actually am the *opposite*. I tend to think louder cars feel slower - at least cars like ours. With an uncorked exhaust, you lean into the pedal, it get's really loud but the car doesn't really do that much.

Anyways I do think it could be psycological. Same mods, same fuel, different days, the car can feel faster or slower depending on my mood/awareness. But then again I've tried E85 for at least two full tanks. I *do* remember feeling a minor difference but nothing like the difference when I installed my aftermarket header.

[tomm.brz]

Originally Posted by ermax

I'm not implying people do things because they want it to be louder but that people tend to associate louder with faster. You may want your car to be quiet but that doesn't mean that if something made it louder it wouldn't trick you into feeling like it got faster too. I've seem people make changes to their car and say how much faster it feels and it turns out it actually got slower. The butt dyno is very inaccurate is all I'm getting at.

sooooo true

it is so easy to make our engine louder just messing with VVT, and what you get maybe is just louder farting and more fuel used, and car goes slower and less reactive