timing with boost and E85....
11-16-2011, 09:31 PM
#1
timing with boost and E85.... compared to 93 pump in LSx engines.
I know it is all relative to CR and many other variables but I'm curious if the stock block LS engines can handel the added tq and timing that E85 allows?
example: On my 2.0L nissan engine I run 21 deg timing with no issues and any boost level with E85 and I rna 15deg with 93 pump gas at high boost.
The peolpe that I know ar running 15-17°max on 93 with stock piston LS motors. I'm building a L33 turbo 240sx and will be running E85 all the time and I'm curious what will be safe with these motors???
The L33 is 10-1 CR and I will be running a TC78 turbo with 12-18psi depending on how it acts. I don't think it will take as much boost to reach my WHP goals with the higher compression and timing with E85.
So how much timing with E85 on a stock short block L33 5.3L???
I will start out with 15° and go from there. The main reason for E85 is to allow me to keep the good flowwing 799's and the 10-1 CR and still be able to run higher boost levels without detontation. I know each build and tune is different but what should be the expected "sweet spot" on timing with my setup?
From my experience with imports it is very hard to get E85 to knock. I have runn as much as 24-25 deg timing up top on my 4cyl @25+psi with no problems with stock pistons and 9-1 CR.
I know it is all relative to CR and many other variables but I'm curious if the stock block LS engines can handel the added tq and timing that E85 allows?
example: On my 2.0L nissan engine I run 21 deg timing with no issues and any boost level with E85 and I rna 15deg with 93 pump gas at high boost.
The peolpe that I know ar running 15-17°max on 93 with stock piston LS motors. I'm building a L33 turbo 240sx and will be running E85 all the time and I'm curious what will be safe with these motors???
The L33 is 10-1 CR and I will be running a TC78 turbo with 12-18psi depending on how it acts. I don't think it will take as much boost to reach my WHP goals with the higher compression and timing with E85.
So how much timing with E85 on a stock short block L33 5.3L???
I will start out with 15° and go from there. The main reason for E85 is to allow me to keep the good flowwing 799's and the 10-1 CR and still be able to run higher boost levels without detontation. I know each build and tune is different but what should be the expected "sweet spot" on timing with my setup?
From my experience with imports it is very hard to get E85 to knock. I have runn as much as 24-25 deg timing up top on my 4cyl @25+psi with no problems with stock pistons and 9-1 CR.
11-16-2011, 11:34 PM
#2
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If you tune until you see knock, then back it down a degree or two, then what is the difference between an import engine and any other engine? Do the same thing... Start at 15* and start working up. Tuning the engine for power is the same process.
12-02-2011, 07:02 PM
#3
I wouldn't tune the ignition to the point of knock. On alternative fuels this can result in more timing that you can use.
The engine will tell you when it has enough timing.
You should start very conservative, say around 10 degrees.
Using a dyno would be best, but in lieu of that, find a quiet piece of road you can run repeatedly on.
Download the aDyno app for android, or RPM for apple, or buy/borrow/use a g-tec/v box and look at your g's while accelerating through a gear. I like to sweep through second myself.
Keeping your AFR's the same, advance timing 2-3 degrees at a time until you either experience knock or reach peak horsepower or g's. Which ever happens first. Then back off 1-2 degrees for a margin.
You may have to do another timing sweep when the temperature changes and scale your IAT/Timing tables accordingly.
The engine will tell you when it has enough timing.
You should start very conservative, say around 10 degrees.
Using a dyno would be best, but in lieu of that, find a quiet piece of road you can run repeatedly on.
Download the aDyno app for android, or RPM for apple, or buy/borrow/use a g-tec/v box and look at your g's while accelerating through a gear. I like to sweep through second myself.
Keeping your AFR's the same, advance timing 2-3 degrees at a time until you either experience knock or reach peak horsepower or g's. Which ever happens first. Then back off 1-2 degrees for a margin.
You may have to do another timing sweep when the temperature changes and scale your IAT/Timing tables accordingly.
12-10-2011, 12:12 AM
#5
Thanks for the input. I know skinnies is running the same L33 5.3L that I've got and he is running E85 and 20° timing at 20psi of boost. I'll start at 15° and go from there. I run 22-24° on my sr20 4cyl with E85 at 25psi of boost but it'a 8.5-1 and the L33's are 10-1 CR.
12-10-2011, 03:27 AM
#6
Every engine/ car is going to be different. There's a lot of variables that come into play, IAT's, engine loading/vehicle weight, E-85 is pretty leniate with how much Boost/timing you can run. How much boost do you plan on runing? For reference I run 18psi with 19* with 91oct and M1 methanol and haven't had any issues.....E-85 is way better then that as well. Start at 15* like you said and go from there....just remember to take into account any possible atmospheric changes and don't tune it to the ragged edge.
