Timing curve (Built motors)
12-28-2014, 10:23 AM
#1
I'm curious what you guys consider (median) timing meaning not super conservative yet not out of control for the following KPA ranges with IAT well below 150 degrees. I'm also curious to see what type of cuts back at different temp ranges etc. Basically what ever you guys are doing at these ranges.
370ci
L92 heads
9.4:1 compression
Forged rods/Pistons
Intercooled
No meth
(2) 66/65 turbos
93 octane
227/231 .624/.598 115+4
7k Max RPM
I'm going to be making some changes here shortly as I'm currently running off the gate @ 6ish lbs and 13 deg on anything about 135 kPa. The car is a turd and I'm ready to turn it up
136 kPa (5 psi)=
157 kPa (8 psi)=
177 kPa (11psi)=
198 kPa (14psi)=
219 kPa (17psi)=
239 kPa (20psi)=
267 kPa (24psi)=
370ci
L92 heads
9.4:1 compression
Forged rods/Pistons
Intercooled
No meth
(2) 66/65 turbos
93 octane
227/231 .624/.598 115+4
7k Max RPM
I'm going to be making some changes here shortly as I'm currently running off the gate @ 6ish lbs and 13 deg on anything about 135 kPa. The car is a turd and I'm ready to turn it up
136 kPa (5 psi)=
157 kPa (8 psi)=
177 kPa (11psi)=
198 kPa (14psi)=
219 kPa (17psi)=
239 kPa (20psi)=
267 kPa (24psi)=
Last edited by oscs; 12-28-2014 at 11:10 AM.
12-28-2014, 10:40 AM
#2
I'm curious what you guys consider (median) timing meaning not super conservative yet not out of control for the following KPA ranges with IAT well below 150 degrees. I'm also curious to see what type of cuts back at different temp ranges etc. Basically what ever you guys are doing at these ranges.
regardless... I'd tune them all the same. Start at a known "safe" level.
136 kPa (5 psi)= 10*
157 kPa (8 psi)= 10*
177 kPa (11psi)= 10*
198 kPa (14psi)= 9*
219 kPa (17psi)= 9*
239 kPa (20psi)= 8*
267 kPa (24psi)= 8*
157 kPa (8 psi)= 10*
177 kPa (11psi)= 10*
198 kPa (14psi)= 9*
219 kPa (17psi)= 9*
239 kPa (20psi)= 8*
267 kPa (24psi)= 8*
Best done on a dyno. I use the track because I'm too cheap to dyno. On my specific setup I'd see about 1-1.5+ MPH gain per degree of timing. As as you get closer to your peak torque timing the gains start to drop off. I stop adding timing when I see less than 1mph improvement at the track.
I'm sure you'll end up with more than 13* at 6lbs, but I'd be looking more at rising the boost and less at advancing the timing in your case. I fart harder than 6lbs...
You start seeing monster gains per pound of boost once you're on the best efficiency island on your compressor map. You are nowhere near that at 6lbs. Last edited by Forcefed86; 12-28-2014 at 10:53 AM.
12-28-2014, 10:53 AM
#3
Whats a built motor? Head design? Bore? RPM range? Cam? Compression? Fuel used? Etc...
regardless... I'd tune them all the same. Start at a known "safe" level.
Dial in your boost and AFR on those settings then bump timing up slowly until you stop seeing the usual healthy gains.
Best done on a dyno. I use the track because I'm too cheap to dyno. On my specific setup I'd see about 1-1.5+ MPH gain per degree of timing. As as you get closer to your peak torque timing the gains start to drop off. I stop adding timing when I see less than 1mph improvement at the track.
I'd be looking more at rising the boost and less at advancing the timing in your case. I fart harder than 6lbs...
regardless... I'd tune them all the same. Start at a known "safe" level.
Dial in your boost and AFR on those settings then bump timing up slowly until you stop seeing the usual healthy gains.
Best done on a dyno. I use the track because I'm too cheap to dyno. On my specific setup I'd see about 1-1.5+ MPH gain per degree of timing. As as you get closer to your peak torque timing the gains start to drop off. I stop adding timing when I see less than 1mph improvement at the track.
I'd be looking more at rising the boost and less at advancing the timing in your case. I fart harder than 6lbs...
I typically run N/A timing with 67mm or larger twins or an 88mm single up through 3 to 4 lbs of boost then start pulling out 3 degrees of timing per lb of boost through 10lbs of boost. Then a little softer timing pull per lb of boost form there until I reach 10 degrees of timing total. As mentioned above, then start adding timing back in either on the dyno or track until every degree of timing is not adding 1mph of trap speed or 10 - 15hp + on dyno.
If you have smaller size turbos / larger CI motor, the above advice should be scaled back even further. For drag cars I like late hitting FI set ups for reliability.
12-28-2014, 10:55 AM
#4
Whats a built motor? Head design? Bore? RPM range? Cam? Compression? Fuel used? Etc... regardless... I'd tune them all the same. Start at a known "safe" level. Dial in your boost and AFR on those settings then bump timing up slowly until you stop seeing the usual healthy gains. Best done on a dyno. I use the track because I'm too cheap to dyno. On my specific setup I'd see about 1-1.5+ MPH gain per degree of timing. As as you get closer to your peak torque timing the gains start to drop off. I stop adding timing when I see less than 1mph improvement at the track. I'm sure you'll end up with more than 13* at 6lbs, but I'd be looking more at rising the boost and less at advancing the timing in your case. I fart harder than 6lbs... You start seeing monster gains per pound of boost once you're on the best efficiency island on your compressor map. You are nowhere near that at 6lbs.
You start seeing monster gains per pound of boost once you're on the best efficiency island on your compressor map. You are nowhere near that at 6lbs.
turning up the boost is definetly where I'm looking to make big gains but I figure if couple it with a solid timing graph while I was at it. I have some 14lb springs laying around that I am just itching to put in.. But 5lbs to 14lbs is a big *** jump.
Last edited by oscs; 12-28-2014 at 11:27 AM.
12-28-2014, 11:18 AM
#6
Unless your compression or CC design changes, forged internals have zero effect on your peak torque timing levels. If you're not octane limited, peak torque timing will be the same. Personally I shy well way from peak torque timing.
LS engines have fast burn head design. In general they require little timing compared to older designs. The smaller the CC the less advance is necessary. The 4" bore will require a tad more timing than the 3.7x stuff.
Perfect AFR will vary depending on who you talk to...
The richer the mixture the slower the burn, which will require more IGN lead. Many associate more lead with more power, which is generally false. Leaner mixtures will burn more quickly/efficiently while requiring less IGN lead. You always want to shoot for the least amount of lead necessary make peak torque. Rich AFR's and elevated timing levels are not the way to do this.
For general hobby cars like yours and mine, I believe the above holds true. Once you get into huge race engines, high duration cams, high rpm... etc most of this goes out the window.
LS engines have fast burn head design. In general they require little timing compared to older designs. The smaller the CC the less advance is necessary. The 4" bore will require a tad more timing than the 3.7x stuff.
Perfect AFR will vary depending on who you talk to...
The richer the mixture the slower the burn, which will require more IGN lead. Many associate more lead with more power, which is generally false. Leaner mixtures will burn more quickly/efficiently while requiring less IGN lead. You always want to shoot for the least amount of lead necessary make peak torque. Rich AFR's and elevated timing levels are not the way to do this.
For general hobby cars like yours and mine, I believe the above holds true. Once you get into huge race engines, high duration cams, high rpm... etc most of this goes out the window.
12-28-2014, 11:24 AM
#7
im running 93 pump only on my 6.0 and it is much milder than yours im at
19*at 125 kpa
11.5*at 150 kpa 7.3 psi and
10* at 220 kpa
with a 10# spring I end up at just under 11* timing
runs 10.50s at 130 mph on that timing and boost, 11.4 afr, 3600lbs thru exaust. 3.23 gear.
im sure I can get away with 12# or 13# boost and get in the nines that way on 93 no meth.
19*at 125 kpa
11.5*at 150 kpa 7.3 psi and
10* at 220 kpa
with a 10# spring I end up at just under 11* timing
runs 10.50s at 130 mph on that timing and boost, 11.4 afr, 3600lbs thru exaust. 3.23 gear.
im sure I can get away with 12# or 13# boost and get in the nines that way on 93 no meth.
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12-28-2014, 11:31 AM
#8
im running 93 pump only on my 6.0 and it is much milder than yours im at 19*at 125 kpa 11.5*at 150 kpa 7.3 psi and 10* at 220 kpa with a 10# spring I end up at just under 11* timing runs 10.50s at 130 mph on that timing and boost, 11.4 afr, 3600lbs thru exaust. 3.23 gear. im sure I can get away with 12# or 13# boost and get in the nines that way on 93 no meth.
12-28-2014, 11:33 AM
#9
Unless your compression or CC design changes, forged internals have zero effect on your peak torque timing levels. If you're not octane limited, peak torque timing will be the same. Personally I shy well way from peak torque timing. LS engines have fast burn head design. In general they require little timing compared to older designs. The smaller the CC the less advance is necessary. The 4" bore will require a tad more timing than the 3.7x stuff. Perfect AFR will vary depending on who you talk to... The richer the mixture the slower the burn, which will require more IGN lead. Many associate more lead with more power, which is generally false. Leaner mixtures will burn more quickly/efficiently while requiring less IGN lead. You always want to shoot for the least amount of lead necessary make peak torque. Rich AFR's and elevated timing levels are not the way to do this. For general hobby cars like yours and mine, I believe the above holds true. Once you get into huge race engines, high duration cams, high rpm... etc most of this goes out the window.
Last edited by oscs; 12-28-2014 at 11:40 AM.
12-28-2014, 11:35 AM
#10
All good advice above. Very conservative as he mentioned. Your setup details will steer advice more one way or another. I typically run N/A timing with 67mm or larger twins or an 88mm single up through 3 to 4 lbs of boost then start pulling out 3 degrees of timing per lb of boost through 10lbs of boost. Then a little softer timing pull per lb of boost form there until I reach 10 degrees of timing total. As mentioned above, then start adding timing back in either on the dyno or track until every degree of timing is not adding 1mph of trap speed or 10 - 15hp + on dyno. If you have smaller size turbos / larger CI motor, the above advice should be scaled back even further. For drag cars I like late hitting FI set ups for reliability.
12-28-2014, 12:24 PM
#11
Really though, without a track or dyno I would not push too hard.
12-28-2014, 12:48 PM
#12
Yeah I don't trust the calculators too much. As I likely won't have hard data to work off of (besides logs.) It would be nice to have an idea of what is to much/little when I start to dial it in on the street. Ie. What are guys pushing it to at those levels.
12-28-2014, 01:22 PM
#13
you need to sneak up on it though . as what works for short bursts on the street will almost always be to aggressive for a full track run.mine was at 13* at 10# and was getting spark knock in high gear so I pulled 2* and added a little fuel and it works at the track for me. I was around 11.7 wot and at 13* it was pinging a little. I do still have a 195* t-stat so im sure a 160* whould help.
12-28-2014, 02:56 PM
#14
My 10:1 5.3 ran on the ragged edge around 17* and 25lbs. After about 10-15 runs at this level it eventually pushed the HG. This was E85, intercooled, and water/meth inj. as well.
You'll probably end up with something like Matts pump gas table below. I'd still start out lower.
Attachment 724072
12-28-2014, 03:23 PM
#15
IMO you should just have a **** for timing with zero numbers involved. Start out "low", slowly "turn it up" until it stops making power. Aiming for a specific number is pointless. My 10:1 5.3 ran on the ragged edge around 17* and 25lbs. After about 10-15 runs at this level it eventually pushed the HG. This was E85, intercooled, and water/meth inj. as well. You'll probably end up with something like Matts pump gas table below. I'd still start out lower.
Last edited by oscs; 12-28-2014 at 03:29 PM.
12-28-2014, 04:27 PM
#16
was just going to post up my table and saw it already here haha and suggest starting lower also and checking results, these motors start dropping off power long before they start having issues with knock and etc, theyll talk you just gotta not be greedy and listen.
usually good rule of thumb 0psi 22deg, 14psi 14deg, and then start moving around from there, every combo starts to vary at 14+ psi i would say.
usually good rule of thumb 0psi 22deg, 14psi 14deg, and then start moving around from there, every combo starts to vary at 14+ psi i would say.
12-28-2014, 05:36 PM
#17
was just going to post up my table and saw it already here haha and suggest starting lower also and checking results, these motors start dropping off power long before they start having issues with knock and etc, theyll talk you just gotta not be greedy and listen. usually good rule of thumb 0psi 22deg, 14psi 14deg, and then start moving around from there, every combo starts to vary at 14+ psi i would say.