Let's Talk Timing Maps

[Greg E]

IDK about tuning 4th gear on the street either, it's 150 at like 7000. It was hard enough finding a good spot for 3rd gear pulls

The idea is to just get into the high load/low RPM area of the map.

[niterydr]

After browsing I've realized my post count and contributions are dismal to say the least. So lets get 2 setups posted to help the masses. One a healthy bolt on TD04 setup, one my old blue car where I had no limits and literally put it on the dyno to find limits of octane or parts.

A few notes:

• These are all AEM V1 maps
• These are all cars that have/had run a VERY LONG time and put up good numbers/durability
• These all had manipulators but these are some base-maps. I wouldn't suggest ever plugging these into your map and letting it rip, but it gets you started for reference. If you have a question ask, don't try to reverse engineer my stuff. Here to help

First up is a calibrated 2g ECU. 13t car, pump gas, roughly 400awhp on a dyno dynamics brand dyno without correction @ around 17-18psi.

400_400_2g3s_pump_13t_SMIC.jpg

Last up, a peak into insanity. Load bearing dyno tuned up to roughly 28psi or around 650awhp. Then we had to switch to sweeps (versus holding it there and pounding timing at it). 720.2awhp uncorrected the heads buckled (ARPs torqued to 105 ft lbs, non pinned heads as this is 2006), roughly 33psi on the map sensor, 592 torque. I knew we were flirting with disaster, we calculated yield to be around 712awhp (very long story how we cam to calculate clamp force based off assumed cylinder pressure based on raw torque output on the dyno) and this was seriously the last pull, and well the heads yielded. No knock, C-16 fuel. Bearings perfect on tear down. Car never ran afterwards except in and out of the shop to be town down for a single setup that never worked. (this is my old blue stealth with 620awhp uncorrected it did trap around 136mph). This is seriously pushing the fuel to 13.0AFR (burned the best there on this setup) and adding timing until it came back with no gains and backing it back down a bit (usually pulling between .3 to 1.2 degree resulted in a 2-10hp drop).

720_592_3L_1g3s.jpg

Have at it! Hope it helps.

[familyMAN]

Why are you running more timing around 5k, which was probably peak tq, and then drop up top on the big build? That goes against every other tuning strategy I have ever seen on a turbo car.

Josh, I know you have WAY more tuning experience than me but 30* at your peak tq (cylinder pressure) at 30psi sounds like you were trying to pop a head gasket. Cut that in half and keep the timing the same up top and you would've made the same HP, correct? And maybe saved the HG and car would still be together since it led to the tear down and part out

Let me know what I am missing!

Edit: also, why calculate "head" yield on HP? Wouldn't it be related to TQ/cylinder pressure? My understanding is the head studs shouldn't care about low tq, high rpm, high hp. They care about high cylinder pressure and tq.

[niterydr]

Why are you running more timing around 5k, which was probably peak tq, and then drop up top on the big build? That goes against every other tuning strategy I have ever seen on a turbo car.

Josh, I know you have WAY more tuning experience than me but 30* at your peak tq (cylinder pressure) at 30psi sounds like you were trying to pop a head gasket. Cut that in half and keep the timing the same up top and you would've made the same HP, correct? And maybe saved the HG and car would still be together since it led to the tear down and part out

Let me know what I am missing!

Edit: also, why calculate "head" yield on HP? Wouldn't it be related to TQ/cylinder pressure? My understanding is the head studs shouldn't care about low tq, high rpm, high hp. They care about high cylinder pressure and tq.

Great questions lets discuss!

The ultimate goal for timing is to tune for MBT. You want the timing to create the maximum efficiency and that the flame gets across that piston with the best advantage after TDC (this is why you want to "back into" timing adjustments, there is typically a window of timing that will produce the same torque output but just increase cylinder pressure). What if I told you I actually had another 4-5 degrees in it just to test this theory? Well I did, it made no more power or noise, but I assume cylinder pressure was much much higher. I wish I had Ion knock sensing then (and now, its on my to buy tool list).

I'll demonstrate with a graph and explain. Taken from a good read: "FUNDAMENTALS OF INTERNAL COMBUSTION ENGINES" by H. N. Gupta (I need to find my copy somewhere).
mbt and spark advance.jpg

Anyway, with the C16 we were not anywhere knock limited and thus could actually push to MBT, essentially until the car stopped making power. Then we'd back it down. I would push the setup until it would only pick up 1-4hp and then back it down. If I cut the timing in say half, I would have left a good 60-80hp on the table EASILY. With a load bearing dyno and unlimited dyno pulls (I think we experimented different cam settings, fuel octanes, intercooler setups to the tune of roughly 300 pulls?) you can back your way into data slowly.
Frankly the car kept making more and more power with the timing so I kept adding it. Again it is just a number on this basemap and was for the setting. On this setup (again in 2006) the delta cam grinds were not doing us any favors neither were the 50 trims at full tilt, so VE really didn't seem to increase much after peak torque. It didn't get much worse, just this car always flattened out after it "came on". Which proves another point, every setup is different. The car didn't let go at peak torque it let go afterwards, see below dip in dynochart, that is with it pushing coolant. Again it was an in-house "social" experiment just to see how far things could get pushed. (FYI: with 15 degrees of timing on the C16 the setup would actually misfire horribly due to the 2 heat range colder plugs and just how much a bear C16 is).

dyno.jpg

Another note:

Calculating to HP, good observation We actually calculated it to raw tractive effort (raw torque output on the dyno) then translated it into a horsepower figure to know where we should slow down. It much easier to look for a HP number (which is a function of torque and RPM, another reason the timing flat lined, I knew I had a ceiling and didn't want to exceed it). To be honest I had weather corrections on and the way the intake air temperature sensor for the dyno was positioned versus the dyno room fan, it was actually taking away horsepower (dynos are tricky tools, very easy to manipulate numbers in error and of course on purpose). When I was doing this live, if memory serves correct, the dyno showed 705hp so I thought we were close but safe. Again playing with fire, I knew the risks.

I hope that helps. Gotta to run to pick-up a snowblower, but I hope this discussion continues. On a side note, you stopped sending me logs

*cliff notes: I didn't keep add timing as rpm increased as I didn't want any more power, I wanted right around 715 and to keep it there**

[familyMAN]

Josh, Thanks for the discussion. I knew you wouldn't take my questions defensively. Surprising to me based on what I understand that you would blow a gasket after surviving peak tq unless you were near or past mbt in the upper rpms, creating more cylinder pressure than needed.

Logs are a pain to send back and forth. What we need to do is rent a dyno!! Not sure I gave you latest update on car, but it's down for a proper build instead of stock crap so I can safely crank boost and timing to wring out these little 14b hair dryers.

Too bad you never hit the track with the 700+ tune. Big traps were in store based on 600 results!

[niterydr]

Josh, Thanks for the discussion. I knew you wouldn't take my questions defensively. Surprising to me based on what I understand that you would blow a gasket after surviving peak tq unless you were near or past mbt in the upper rpms, creating more cylinder pressure than needed.

Logs are a pain to send back and forth. What we need to do is rent a dyno!! Not sure I gave you latest update on car, but it's down for a proper build instead of stock crap so I can safely crank boost and timing to wring out these little 14b hair dryers.

Too bad you never hit the track with the 700+ tune. Big traps were in store based on 600 results!

Sounds good! Those b wheels loose efficiency pretty quickly after say 25-28psi. I do regret not getting it to the track with another 100+hp nearly everywhere over the 136mph traps, oh well.

[niterydr]

Josh, Thanks for the discussion. I knew you wouldn't take my questions defensively. Surprising to me based on what I understand that you would blow a gasket after surviving peak tq unless you were near or past mbt in the upper rpms, creating more cylinder pressure than needed.

Logs are a pain to send back and forth. What we need to do is rent a dyno!! Not sure I gave you latest update on car, but it's down for a proper build instead of stock crap so I can safely crank boost and timing to wring out these little 14b hair dryers.

Too bad you never hit the track with the 700+ tune. Big traps were in store based on 600 results!

Sounds good! Those b wheels loose efficiency pretty quickly after say 25-28psi. I do regret not getting it to the track with another 100+hp nearly everywhere over the 136mph traps, oh well.

[familyMAN]

Yep, figured happy zone will be around 25-26psi so reducing as much back pressure as possible to help out the little comp wheel....Modding my 3sx kit for WG dumps and I opened up the downpipe to 4" and doing 4" single. Will post timing maps when I get it cranked up. I know there's a lot of power to be had since 1* of timing picked up 20awtq on setup, before tearing down and going a little crazy with build to work the 14bs

[J. Fast]

Great questions lets discuss!

The ultimate goal for timing is to tune for MBT. You want the timing to create the maximum efficiency and that the flame gets across that piston with the best advantage after TDC (this is why you want to "back into" timing adjustments, there is typically a window of timing that will produce the same torque output but just increase cylinder pressure). What if I told you I actually had another 4-5 degrees in it just to test this theory? Well I did, it made no more power or noise, but I assume cylinder pressure was much much higher. I wish I had Ion knock sensing then (and now, its on my to buy tool list).

I'll demonstrate with a graph and explain. Taken from a good read: "FUNDAMENTALS OF INTERNAL COMBUSTION ENGINES" by H. N. Gupta (I need to find my copy somewhere).
mbt and spark advance.jpg

Anyway, with the C16 we were not anywhere knock limited and thus could actually push to MBT, essentially until the car stopped making power. Then we'd back it down. I would push the setup until it would only pick up 1-4hp and then back it down. If I cut the timing in say half, I would have left a good 60-80hp on the table EASILY. With a load bearing dyno and unlimited dyno pulls (I think we experimented different cam settings, fuel octanes, intercooler setups to the tune of roughly 300 pulls?) you can back your way into data slowly.
Frankly the car kept making more and more power with the timing so I kept adding it. Again it is just a number on this basemap and was for the setting. On this setup (again in 2006) the delta cam grinds were not doing us any favors neither were the 50 trims at full tilt, so VE really didn't seem to increase much after peak torque. It didn't get much worse, just this car always flattened out after it "came on". Which proves another point, every setup is different. The car didn't let go at peak torque it let go afterwards, see below dip in dynochart, that is with it pushing coolant. Again it was an in-house "social" experiment just to see how far things could get pushed. (FYI: with 15 degrees of timing on the C16 the setup would actually misfire horribly due to the 2 heat range colder plugs and just how much a bear C16 is).

dyno.jpg

Another note:

Calculating to HP, good observation We actually calculated it to raw tractive effort (raw torque output on the dyno) then translated it into a horsepower figure to know where we should slow down. It much easier to look for a HP number (which is a function of torque and RPM, another reason the timing flat lined, I knew I had a ceiling and didn't want to exceed it). To be honest I had weather corrections on and the way the intake air temperature sensor for the dyno was positioned versus the dyno room fan, it was actually taking away horsepower (dynos are tricky tools, very easy to manipulate numbers in error and of course on purpose). When I was doing this live, if memory serves correct, the dyno showed 705hp so I thought we were close but safe. Again playing with fire, I knew the risks.

I hope that helps. Gotta to run to pick-up a snowblower, but I hope this discussion continues. On a side note, you stopped sending me logs

*cliff notes: I didn't keep add timing as rpm increased as I didn't want any more power, I wanted right around 715 and to keep it there**

Excellent post sir... This post comes right out of EFI University Manual. I took a picture of the graph and attempted to have a discussion a few years ago regarding timing maps and was superinflamo'd from guys that say you need a head lift fix... We're building 1000+hp engines (uncorrected familyguy) in Denver without pinned heads because of this little chart right here. UPPCOS is pushing 1200bhp on his Meth/Eth engine build on stock heads/cams with Aermet ARP hardware. I'm now at 800. No O-rings or Compression rods... just bolts.

When you pass MBT all you create is excess cylinder pressure at the same hp and you pound your bearings flat.

[familyMAN]

We're building 1000+hp engines (uncorrected familyguy) in Denver without pinned heads because of this little chart right here. UPPCOS is pushing 1200bhp on his Meth/Eth engine build on stock heads/cams with Aermet ARP hardware. I'm now at 800. No O-rings or Compression rods... just bolts.

Can you post your 800 uncorrected chart? Just last week you posted 7xx corrected, 590 uncorrected. That's a big jump and would definitely be a feat at your altitude.