93 ocT "10% ethanol" = 13.5 AFR-WOT
Feb 19, 2008, 11:43 AM
#32
That pic looks strange... is it like the "WGA spring mod" where you add an extra spring between the flapper lever and the WGA? I can't see your WGA rod... is it replaced by the spring?
You say its working great... please detail. I currently have the "WGA spring mod" w/ the extra spring hooked up... but I only hold .5psi more at redline... if that. So I'm thinking that was a horrible failure.
You say its working great... please detail. I currently have the "WGA spring mod" w/ the extra spring hooked up... but I only hold .5psi more at redline... if that. So I'm thinking that was a horrible failure.
Feb 19, 2008, 04:40 PM
#34
FYI, pretty soon the entire USA will have a MINIMUM of 10% ethanol by volume in the gas. Its federally mandated. All vehicles built since 1995 I think were federally mandated to perform with up to 10% ethanol with their fuel systems. This is one reason manufacturers seem to have there open loop fueling very rich from the factory.
I've seen up to 20% ethanol pumps around here. As far as it helping with knock, barely. Its still a 93 octane (R+M/2) mix which is rated by the ability to resist knock. At a 90/10% split, its not doing enough to do much but lessen your gas mileage very slightly.
I've seen up to 20% ethanol pumps around here. As far as it helping with knock, barely. Its still a 93 octane (R+M/2) mix which is rated by the ability to resist knock. At a 90/10% split, its not doing enough to do much but lessen your gas mileage very slightly.
Feb 19, 2008, 04:52 PM
#36
The wastegate opens before peak boost, with the actuator arm pushing it open, or pulling it closed, very quickly, this is how boost is controlled. If it didn't you would get the absolute max boost the turbo could do, which is over 30psi.
If you are running C16 and want as much boost as possible then this could work I guess, but it would be better to just weld the wastegate closed as I can imagine even the tightest spring couldn't keep the exhaust gases from opening the wastegate, also with a spring you would get some serious wastegate flutter as the spring fights against the exhaust gases the boost would be up and down, up and down. It would be like playing tug-rope.
What I imagine he is doing is *adding* the spring to the wastegate actuator, therefore adding some more pre-tension to the assembly.
Last edited by razorlab; Feb 19, 2008 at 04:56 PM.
Feb 19, 2008, 05:04 PM
#38
By law, they have to advertise the ACTUAL octane rating coming out of the spout. The biggest benefit is they get to refine 91 octane for the blend rather than 93.
I also have used them back to back with the EXACT same lambda curve tuning for each. Same counts of knock in the same areas on occasion.
Here is some old info I posted ages ago in a thread regarding additives which boost octane.
https://www.evolutionm.net/forums/sh...5&postcount=51
Last edited by Jack_of_Trades; Feb 19, 2008 at 10:19 PM.
Feb 19, 2008, 07:29 PM
#39
The spring just adds a a little extra tension to the already existing internal spring. Basically does the same thing as a WGA with stronger spring but it's FREE. Peak boost is the same as it was w/o the mod, mbc adjusted (30 psi), but it adds about 2 more psi at redline.
The reason it helps at higher rpm is because exhaust backpressure increases in proportion to rpm, but with stock turbo boost psi increases to load.
Basically got 2 psi more at redline, same peak psi, and much faster spool.
The reason it helps at higher rpm is because exhaust backpressure increases in proportion to rpm, but with stock turbo boost psi increases to load.
Basically got 2 psi more at redline, same peak psi, and much faster spool.
Feb 19, 2008, 10:10 PM
#40
That doesn't make any sense and wouldn't work at all. You would get no control whatsoever as the only thing the spring would be doing is trying to keep the wastegate closed, all the time. The only thing that would open the wastegate with just the spring there would be exhaust pressure.
The wastegate opens before peak boost, with the actuator arm pushing it open, or pulling it closed, very quickly, this is how boost is controlled. If it didn't you would get the absolute max boost the turbo could do, which is over 30psi.
If you are running C16 and want as much boost as possible then this could work I guess, but it would be better to just weld the wastegate closed as I can imagine even the tightest spring couldn't keep the exhaust gases from opening the wastegate, also with a spring you would get some serious wastegate flutter as the spring fights against the exhaust gases the boost would be up and down, up and down. It would be like playing tug-rope.
What I imagine he is doing is *adding* the spring to the wastegate actuator, therefore adding some more pre-tension to the assembly.
The wastegate opens before peak boost, with the actuator arm pushing it open, or pulling it closed, very quickly, this is how boost is controlled. If it didn't you would get the absolute max boost the turbo could do, which is over 30psi.
If you are running C16 and want as much boost as possible then this could work I guess, but it would be better to just weld the wastegate closed as I can imagine even the tightest spring couldn't keep the exhaust gases from opening the wastegate, also with a spring you would get some serious wastegate flutter as the spring fights against the exhaust gases the boost would be up and down, up and down. It would be like playing tug-rope.
What I imagine he is doing is *adding* the spring to the wastegate actuator, therefore adding some more pre-tension to the assembly.
Feb 19, 2008, 10:28 PM
#41
They actually blend 10% ethanol with 91 octane to create the 93 blend. Pure ethanol has an AKI rating of 116 octane, blended with 90% 91 octane equates to 93.5 octane. The RON value for ethanol is 129 whereas the RON value for 91 octane is closer to 95 RON. Combined, thats roughly a 98 RON mixture which is pretty close to the standard 93 AKI rating, it maybe a bit better with the ethanol mix. That could be where any resistance to knock has improved at all.
By law, they have to advertise the ACTUAL octane rating coming out of the spout. The biggest benefit is they get to refine 91 octane for the blend rather than 93.
I also have used them back to back with the EXACT same lambda curve tuning for each. Same counts of knock in the same areas on occasion.
Here is some old info I posted ages ago in a thread regarding additives which boost octane.
https://www.evolutionm.net/forums/sh...5&postcount=51
By law, they have to advertise the ACTUAL octane rating coming out of the spout. The biggest benefit is they get to refine 91 octane for the blend rather than 93.
I also have used them back to back with the EXACT same lambda curve tuning for each. Same counts of knock in the same areas on occasion.
Here is some old info I posted ages ago in a thread regarding additives which boost octane.
https://www.evolutionm.net/forums/sh...5&postcount=51
Also if you are correct, how do they come up with E10 87 octane? Using your method it would require them mixing ethanol with 84 octane fuel. I don't think 84 octane exists.
And don't forget about the better latent heat of vaporisation of ethanol which "cools" the burn helping with knock resistance.
Last edited by mplspilot; Feb 19, 2008 at 10:34 PM.
Feb 19, 2008, 11:10 PM
#42
What's your source for this info?
Also if you are correct, how do they come up with E10 87 octane? Using your method it would require them mixing ethanol with 84 octane fuel. I don't think 84 octane exists.
And don't forget about the better latent heat of vaporisation of ethanol which "cools" the burn helping with knock resistance.
Also if you are correct, how do they come up with E10 87 octane? Using your method it would require them mixing ethanol with 84 octane fuel. I don't think 84 octane exists.
And don't forget about the better latent heat of vaporisation of ethanol which "cools" the burn helping with knock resistance.
I'm pretty sure that other countries use lesser quality blends than we offer here and since the refineries supply the entire world its very feasible that there is an 84 AKI mix available. Even if there wasn't originally, I can see our gov't demanding it once they started the e10 kick.You are right about the latent heat vaporization being better and that may very well help with knock since it increases the latent heat vaporization by 16%.
I really gotta did through my links but most of it is either from fuel companies or gov't documentation...as well as some chemical comparison research from reputable sources.
here is the only one I have on my laptop, I'll dig some more up for you soon.
http://www.eere.energy.gov/afdc/pdfs/fueltable.pdf
Feb 19, 2008, 11:18 PM
#43
Also if someones wondering why this happens:
Your 12.5 tune gives you 12.5 when you use regular fuel which has 14.7 stoich ratio.
The "gasohol"(oxygenated fuel) has approx 14.7x90%+9.8x10% = ~ 14 stoich.
So 12.5/14 = ~0.9 is the actual lambda you are now running with your tune.
And 0.9 x 14.7 = 13.23 is what the WB shows.
And while it's not the real afr (cause the wideband has 14.7 multiplier) , your lambda of ~0.9 is leaner than your desired 0.85
Your 12.5 tune gives you 12.5 when you use regular fuel which has 14.7 stoich ratio.
The "gasohol"(oxygenated fuel) has approx 14.7x90%+9.8x10% = ~ 14 stoich.
So 12.5/14 = ~0.9 is the actual lambda you are now running with your tune.
And 0.9 x 14.7 = 13.23 is what the WB shows.
And while it's not the real afr (cause the wideband has 14.7 multiplier) , your lambda of ~0.9 is leaner than your desired 0.85
Feb 20, 2008, 05:44 AM
#44
More significant of an effect on WOT AFR than 10% (or less) ethanol is temperature. This is insane: last Sunday it was mid 70's and the AFR dropped into the mid 11's. Then last night it dipped into the 30's and the AFR leaned almost 2 full points! This is on same tank of gas. Either the temp comp scale is not adjusting enough or it's overadjusting due to much higher than stock pressure levels.
Feb 20, 2008, 06:00 AM
#45
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FYI, pretty soon the entire USA will have a MINIMUM of 10% ethanol by volume in the gas. Its federally mandated. All vehicles built since 1995 I think were federally mandated to perform with up to 10% ethanol with their fuel systems. This is one reason manufacturers seem to have there open loop fueling very rich from the factory.
I've seen up to 20% ethanol pumps around here. As far as it helping with knock, barely. Its still a 93 octane (R+M/2) mix which is rated by the ability to resist knock. At a 90/10% split, its not doing enough to do much but lessen your gas mileage very slightly.
I've seen up to 20% ethanol pumps around here. As far as it helping with knock, barely. Its still a 93 octane (R+M/2) mix which is rated by the ability to resist knock. At a 90/10% split, its not doing enough to do much but lessen your gas mileage very slightly.