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Additional timing with E85

11K views 12 replies 3 participants last post by  Dysan 
#1 ·
G'day, I am fairly new to the mod motor world but have been getting parts to do a bored and stroked 349ci 5.4 based motor. It will be fitted to my Ford Falcon XR8 6M Ute (think Ranchero). The aim is a 11.3 to 11.6 compression ratio, ported 03/04 heads (~295cfm @ 0.400"), Aussie Boss intake, cams will probably be about 230deg @ 0.050 but are to be specced either by my head porter or NA SVT once the engine is largely assembled. It is a daily driver with the view to running it on PULP. ie 98 RON (Australia) / 93 MON (US).

I am curious as to the total timing that could be run on both PULP and when on E85. Down the track I would like to run intercooled low boost 7-10psi on E85.
 
#3 ·
Can't give you a direct comparison but on my last engine which was an aluminum 4.6 (bored .010 and stroked at 3.75) 3-valve 10.3:1 compression with an Edelbrock TVS supercharger I ran as high as 24* timing pushing 18psi of boost on E85. I haven't started testing on my new iron block 11:1 compression engine yet on E85 but I suspect it could use similar timing as my last one.

I didn't keep the timing and boost at that though since my car is mainly a bracket racing car...I ran low boost (8-9psi) and a static 21* of timing from 2500 rpms up when I was in boost.
 
#4 ·
Dysan, thanks for the response. :) That's alot of timing with that much psi. I continue to be amazed by this fuel. Would make it pretty easy to take a 420-450rwhp N/A combo make 700rwhp at 10psi if it could hold 20* or more timing. Your experience suggest it should.
 
#5 ·
From what I have read it is very difficult to make E85 detonate....many people adjust their timing just by adding and adding until the car slows down / looses power and then back it off from there.
 
#6 ·
Unless you find someone with the same setup, you are going to have to figure out how much timing you can run after you are done with the build. This is because many things you are doing will have an impact on knock, as well as MBTT. For example, increasing CR reduces MBTT, as does using ethanol due to its higher burn velocity. Anything that impacts turbulence in the chamber will also impact MBTT. And as mentioned, once you go past MBTT, power and torque will start to drop, as the amount of negative work during the compression stroke starts to go up. Good luck with your build, and let us know how it goes!
 
#7 ·
Thanks to both of you guys. Raised some really good points. I'm starting to think it might be easier to just start to build the tune running on E85 as the first step, and then making a pump fuel tune back from that. Might be a safer way to go.

I have E85 fuel stations not far from me. Only 5 kms / 3 miles away. But, would prefer pump fuel tune for daily duties as I occasionally drive interstate (600-1200mile round trip). Just like i'm doing this weekend :)
 
#8 ·
My engine builder as well as my tuner wanted me to do the initial break-in for my new engine on gas so you may want to consider that. I believe it is just for the initial hits on the engine so the rings are seated...since there will be some extra fuel going down into the oil until the rings seat it is better for that to be gasoline instead of ethanol.

I'm chomping at the bit to get some E85 for my new engine because the low timing on gas is just killing me. Just waiting for a hitch for my wife's new SUV so I can bring my drum to the station.
 
#10 ·
No real set goals, just want it to be consistent since I am a bracket racer. The thing I just don't know is how long my last engine was hurt so I want to initially make some passes at the track without any other changes to see if the new one is any faster. I would be very happy if the car goes somewhere in the 10.9 - 11.0 range since the last one was running 11.3's at my low boost. The edelbrock supercharger unfortunately makes a lot of heat so I can't bracket race with the boost turned up otherwise my air intake temps will go too high and the pcm will pull timing. And for reference my car is in the 3900lb range with me in it so if I wanted to go fast, I'll have to make some good power.
 
#11 ·
Just to give an update, I was able to run the car the other day at the track and it ran exactly what I wanted it to on the first run...10.98 @ 125mph. I then went one pulley down on the supercharger which added about 1.5psi of boost and the car picked up a good amount and ran 10.64. The new engine is working great and the fuel is only 80% ethanol at the moment. Also I am not on my final tune and this started at 16* timing and ended at 20*....when it is all said and done I plan on running a static 21* timing from start to finish of the run so it should pick up more.
 
#12 ·
Thanks for the update. That's a real quick time particularly at a 3900lb weight. Hey you beat your goal of 10.9s as well! You beat it by a 1/4 of a second :) Excellent stuff.

Thanks for the information in regards to timing and boost level as well. Good luck!
 
#13 ·
I've had the car quicker on my last engine...just don't feel like turning up the boost and risking hurting anything. The car has been 10.25 and not even with the smallest pulley on it's last engine. I suspect if I put the 3" pulley(same one I ran 10.25 on the last engine) on this engine it would easily be in the 9's.

Good luck to you as well. I'm looking forward to racing this year!
 
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