Turbo Ls e85 afr and timing
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05-03-2018, 10:25 AM
#8
Originally Posted by 3 window
Set it to “gas AFR” unless you’re going to use the actual AFRs for E85. If you’re more familiar with gas AFRs, it’ll be easier to tune/understand. It’s all off lambda anyway.
05-03-2018, 01:18 PM
#11
Whats bad about these threads is you can have 5-6* of variance in the timing. So if you have not mechanically verified your timing and sync'd that to your ECU... using someones else's numbers can be dangerous.
An indicated 15* on my timing map may only be running 10* actual timing. Then if I plug my 15* number in another engine that reads 6* high, that 15* indicated on the timing map may be 21* actual.
Unless you know your map and the persons timing map you are borrowing from have verified the timing and SYNC'd it 100% correctly... The only right answer is to start at something stupid low like 10* and read the plugs
An indicated 15* on my timing map may only be running 10* actual timing. Then if I plug my 15* number in another engine that reads 6* high, that 15* indicated on the timing map may be 21* actual.
Unless you know your map and the persons timing map you are borrowing from have verified the timing and SYNC'd it 100% correctly... The only right answer is to start at something stupid low like 10* and read the plugs
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0235SS93 (09-12-2023)
05-03-2018, 01:48 PM
#12
Whats bad about these threads is you can have 5-6* of variance in the timing. So if you have not mechanically verified your timing and sync'd that to your ECU... using someones else's numbers can be dangerous.
An indicated 15* on my timing map may only be running 10* actual timing. Then if I plug my 15* number in another engine that reads 6* high, that 15* indicated on the timing map may be 21* actual.
Unless you know your map and the persons timing map you are borrowing from have verified the timing and SYNC'd it 100% correctly... The only right answer is to start at something stupid low like 10* and read the plugs
An indicated 15* on my timing map may only be running 10* actual timing. Then if I plug my 15* number in another engine that reads 6* high, that 15* indicated on the timing map may be 21* actual.
Unless you know your map and the persons timing map you are borrowing from have verified the timing and SYNC'd it 100% correctly... The only right answer is to start at something stupid low like 10* and read the plugs
05-06-2018, 11:01 AM
#13
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depends on exhaust flow and exhaust manifold back pressure and static compression ratio. ill give example for a single turbo with excellent flowing exhaust manifolds and turbo turbine set up. the example will be E85 at 20psi boost on 6.0/6.2 square port heads.
static comp timing
8.1:1 12.0AFR 20psi 16degrees (would likely take 20deg) 1000rwhp
9.1:1 11.5AFR 20psi 14degrees (would likely take 16 deg) 1000rwhp
9.5:1 11.5:1AFR 20psi 13 degrees (would likely take 16deg) 1000rwhp
10.1:1 11.2AFR 20psi 11 degrees (would likely take 14deg) 950rwhp
10.6:1 11.0AFR 20psi 13 degrees (lifted the heads and blew coolant out too much timing for combo) 1100rwhp
static comp timing
8.1:1 12.0AFR 20psi 16degrees (would likely take 20deg) 1000rwhp
9.1:1 11.5AFR 20psi 14degrees (would likely take 16 deg) 1000rwhp
9.5:1 11.5:1AFR 20psi 13 degrees (would likely take 16deg) 1000rwhp
10.1:1 11.2AFR 20psi 11 degrees (would likely take 14deg) 950rwhp
10.6:1 11.0AFR 20psi 13 degrees (lifted the heads and blew coolant out too much timing for combo) 1100rwhp
05-06-2018, 04:31 PM
#14
depends on exhaust flow and exhaust manifold back pressure and static compression ratio. ill give example for a single turbo with excellent flowing exhaust manifolds and turbo turbine set up. the example will be E85 at 20psi boost on 6.0/6.2 square port heads.
static comp timing
8.1:1 12.0AFR 20psi 16degrees (would likely take 20deg) 1000rwhp
9.1:1 11.5AFR 20psi 14degrees (would likely take 16 deg) 1000rwhp
9.5:1 11.5:1AFR 20psi 13 degrees (would likely take 16deg) 1000rwhp
10.1:1 11.2AFR 20psi 11 degrees (would likely take 14deg) 950rwhp
10.6:1 11.0AFR 20psi 13 degrees (lifted the heads and blew coolant out too much timing for combo) 1100rwhp
static comp timing
8.1:1 12.0AFR 20psi 16degrees (would likely take 20deg) 1000rwhp
9.1:1 11.5AFR 20psi 14degrees (would likely take 16 deg) 1000rwhp
9.5:1 11.5:1AFR 20psi 13 degrees (would likely take 16deg) 1000rwhp
10.1:1 11.2AFR 20psi 11 degrees (would likely take 14deg) 950rwhp
10.6:1 11.0AFR 20psi 13 degrees (lifted the heads and blew coolant out too much timing for combo) 1100rwhp
05-06-2018, 05:03 PM
#15
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05-06-2018, 09:23 PM
#17
05-07-2018, 04:06 AM
#18
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I had mine at 11.5 afr, 20* timing, 28psi, approx 1000rwhp. That was pretty much MBT. Funnily enough, I ran the same timing from 19psi and up. I later spoke to another tuner who has tuned a bunch of high hp stuff well over 1000hp and a couple over 1500hp. He said, if it's on E85 he punches in 20 degrees and goes from there, even on the stuff running 40+psi. Says thats just where turbo LS's like timing. I haven't done many but most of them have been around that.
05-07-2018, 10:20 AM
#19
I had mine at 11.5 afr, 20* timing, 28psi, approx 1000rwhp. That was pretty much MBT. Funnily enough, I ran the same timing from 19psi and up. I later spoke to another tuner who has tuned a bunch of high hp stuff well over 1000hp and a couple over 1500hp. He said, if it's on E85 he punches in 20 degrees and goes from there, even on the stuff running 40+psi. Says thats just where turbo LS's like timing. I haven't done many but most of them have been around that.
No motor (e85 LS or otherwise) “likes” a set amount of timing across the board. The charge temps, part combo, and fuel run will determine MBT timing. ETHANOL BURNS FASTER THAN PUMP FUEL, it generally needs less advance to hit MBT timing. While race gas many need much more. Guys that throw in hotter plugs and a ton of timing at E85 tunes don’t have a clue. Read the plugs, period. There is no other correct answer for a “street tuner”. Every combo will differ. I’ve run as high as 30* and as low as 8* on turbo tunes...
Experienced dyno operators/tuner can gauge when you are approaching the MBT timing limit without reading plugs... But most experienced turbo engine tuners won’t shoot for an MBT timing tune anyway. You don’t want giant cylinder pressure peaks near PK TQ. That’s how U detonate, bend rods, and blow head gaskets. Idea is to tune below MBT timing near peak torque to “cushion” the motor and keep cylinder pressure in check. Then ramp timing back in slowly past PK TQ and pour on power in the upper RPM. “Race” stuff usually stalls past 5k and bleeds off a ton of compression at lower RPM with a huge duration cam. So it will have a much more aggressive timing map in general.
05-08-2018, 04:22 AM
#20
Staging Lane
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Sorry mate, didn't mean to upset you, but I think what I've said has been miss interpreted. I was referencing e85 specifically, things are very different for pump obviously. I wasn't saying to punch in 20 degrees and that's the right number, but it's generally in the ballpark, and only a starting point. As opposed to pump where you might start out at a much lower boost number with 10 degrees and gradually sneak both up. For the most part I agree with just about everything you've said. The only other thing I will note which you didnt touch on specifically is EGT. There are instances where you may run a few degrees of extra timing, despite not picking up power, but to see a reduction in EGT. This is obviously on motors that have been built to handle high cylinder pressures (and I guess kind of covered under under your comment of reading plugs)