timing vs AFR

[hakcenter]

Originally Posted by dsm-onster

I had a similar tune. When running no water injection, I ran my 60-1 to 25 psi peeked at 13 degrees timing running 11:1 a/f ratio. No bent rods for thousands of miles of abusive driving.

On what fuel ?

[JayRolla]

I had a similar tune. When running no water injection, I ran my 60-1 to 25 psi peeked at 13 degrees timing running 11:1 a/f ratio. No bent rods for thousands of miles of abusive driving.

Where you also running stock rods and pistons? I know that the forged internals can handle the lower timing without any problems. I was talking to a guy about tuning on another thread a long time ago and it was a wiseman that explained I was giving bad info, I think it was andymoraitis. I was telling the guy to run a little lower timing to get more boost and he was around 14*.

He said thats a real bad no no on stock cast pistons, because going below 14* can cause high EGT's and melt pistons or rods. Maybe I should PM him to give his advice.

[turboglenn]

Originally Posted by JayRolla

Where you also running stock rods and pistons? I know that the forged internals can handle the lower timing without any problems. I was talking to a guy about tuning on another thread a long time ago and it was a wiseman that explained I was giving bad info, I think it was andymoraitis. I was telling the guy to run a little lower timing to get more boost and he was around 14*.

He said thats a real bad no no on stock cast pistons, because going below 14* can cause high EGT's and melt pistons or rods. Maybe I should PM him to give his advice.

Retarding the timing moves the heat from the combustion chamber to the exhaust ports and manifold as the gasses are still burning to an extent when teh exhaust valve opens if timing is too retarded. The heat does not go to the pistons and rodswith less timing, it's more timing that does that by keeping the entire burn cycle in the cylinder before the ex valve opens. The high EGT's are reading in teh manifold, not the cylinder.

Also, anyone who's ever logged a stock ECU should know that the timing gets pulled back to anywhere from 9 - 14* in the beggining of WOT pulls around 4k RPM or so. I don't think Mitsubishi would engineer it that way if it was harmfull to stock internals...

Now, don't take it wrong, i'm not trying to point a finger saying you're wrong, i just want to relay the proper information concerning what gets hot because of certain timing settings.

[dsm-onster]

Originally Posted by hakcenter

On what fuel ?

I've never run anything but pump gas w/ the 60-1

[dsm-onster]

Originally Posted by turboglenn

Retarding the timing moves the heat from the combustion chamber to the exhaust ports and manifold as the gasses are still burning to an extent when teh exhaust valve opens if timing is too retarded. The heat does not go to the pistons and rodswith less timing, it's more timing that does that by keeping the entire burn cycle in the cylinder before the ex valve opens. The high EGT's are reading in teh manifold, not the cylinder.

Also, anyone who's ever logged a stock ECU should know that the timing gets pulled back to anywhere from 9 - 14* in the beggining of WOT pulls around 4k RPM or so. I don't think Mitsubishi would engineer it that way if it was harmfull to stock internals...

Now, don't take it wrong, i'm not trying to point a finger saying you're wrong, i just want to relay the proper information concerning what gets hot because of certain timing settings.

Excellent points! You said it better than I could.

[dsm-onster]

Originally Posted by JayRolla

Where you also running stock rods and pistons? I know that the forged internals can handle the lower timing without any problems. I was talking to a guy about tuning on another thread a long time ago and it was a wiseman that explained I was giving bad info, I think it was andymoraitis. I was telling the guy to run a little lower timing to get more boost and he was around 14*.

He said thats a real bad no no on stock cast pistons, because going below 14* can cause high EGT's and melt pistons or rods. Maybe I should PM him to give his advice.

Stock rods and pistons.

[hakcenter]

Originally Posted by turboglenn

Retarding the timing moves the heat from the combustion chamber to the exhaust ports and manifold as the gasses are still burning to an extent when teh exhaust valve opens if timing is too retarded. The heat does not go to the pistons and rodswith less timing, it's more timing that does that by keeping the entire burn cycle in the cylinder before the ex valve opens. The high EGT's are reading in teh manifold, not the cylinder.

Also, anyone who's ever logged a stock ECU should know that the timing gets pulled back to anywhere from 9 - 14* in the beggining of WOT pulls around 4k RPM or so. I don't think Mitsubishi would engineer it that way if it was harmfull to stock internals...

14* @ 7k rpm, that is where we are all talking about.

What your trying to say is that the gases are 100F - 300F degree's cooler because the explosion happens 8 degree's sooner ? That's a lot of temp for a small amount of duration.

Timing advance increases cylinder pressure, mostly from an entire burn, but somehow the burn being 8 degree's later, is hotter 4 inches away down in the header pipe because its burning up in the pipe as it passes ?

I'm not sold at all, I think something with the fuel atomization during high rpm is the culprit, and the end result being monitor'd istoo far away to register an accurate description of the AFR that really happened. If the AFR is the same, and timing is changed, I think retarded timing would have a more complete atomization, increasing overall heat instead of advanced timing, especially in the short duration that it happens in, in comparison between 8 degree's retarded.

Monster, what pump gas, 91 or 93 ? what % of corny goodness ?

[turboglenn]

hack.. I'm not saying it's any cooler the burn will be teh same temp either way, but it's the time at which you start teh burn that will determine where most of the heat is transferred to. Lighting it earlier to get peak cylinder pressure where you want it in correlation to crank angle to make the most use of the burn for power is why we increase timing and generate more heat inside the cylinder instead of in the ex mani.

Just look at anti-lag.. it sparks the plug ATDC causing most of the explosion's pressure to be generated when the Exh valve is open, thus the majority of the energy created from the "burn" is utilized in the manifold, thus spooling the turbo instead of making power...

also, look at EGT's when you're cruising with 35* or so of timing the EGT's are fairly calm 12-1300F and that's burning at almost the hottest mixture available (14.7:1). But when you go wide open and are only dealing with 18-20* advance and a cooler/richer A/F mix, the EGT's shoot up into the 1500F+ range, because more of the burn is happening later in the engine cycle. Im' not being a smart ass, just sharing info that i've learned over the years. Im also not trying to be "mr know it all" just trying to help others become better informed

14* at redline will yield higher EGT's than 20* at the same load/rpm point since less of the burn is completed before teh exhaust valve begins to open. Meaning the manifold and tubro will be hotter, but internal temps won't change much

[wishihadatalon]

Originally Posted by turboglenn

Retarding the timing moves the heat from the combustion chamber to the exhaust ports and manifold as the gasses are still burning to an extent when teh exhaust valve opens if timing is too retarded. The heat does not go to the pistons and rodswith less timing, it's more timing that does that by keeping the entire burn cycle in the cylinder before the ex valve opens. The high EGT's are reading in teh manifold, not the cylinder.

Also, anyone who's ever logged a stock ECU should know that the timing gets pulled back to anywhere from 9 - 14* in the beggining of WOT pulls around 4k RPM or so. I don't think Mitsubishi would engineer it that way if it was harmfull to stock internals...

Now, don't take it wrong, i'm not trying to point a finger saying you're wrong, i just want to relay the proper information concerning what gets hot because of certain timing settings.

Only one thing that bugs me about this and that is the timing being pulled back on a stock ecu. I can only speculate but to use that as part of the argument is just wrong. Timing is pulled back because peak tq should be right at the onset of boost, so keeping timing low there will help stay away from knock, and also the higher heat generated with the lower timing "should" help spool the turbo.

[wishihadatalon]

Originally Posted by turboglenn

hack.. I'm not saying it's any cooler the burn will be teh same temp either way, but it's the time at which you start teh burn that will determine where most of the heat is transferred to. Lighting it earlier to get peak cylinder pressure where you want it in correlation to crank angle to make the most use of the burn for power is why we increase timing and generate more heat inside the cylinder instead of in the ex mani.

Just look at anti-lag.. it sparks the plug ATDC causing most of the explosion's pressure to be generated when the Exh valve is open, thus the majority of the energy created from the "burn" is utilized in the manifold, thus spooling the turbo instead of making power...

also, look at EGT's when you're cruising with 35* or so of timing the EGT's are fairly calm 12-1300F and that's burning at almost the hottest mixture available (14.7:1). But when you go wide open and are only dealing with 18-20* advance and a cooler/richer A/F mix, the EGT's shoot up into the 1500F+ range, because more of the burn is happening later in the engine cycle. Im' not being a smart ass, just sharing info that i've learned over the years. Im also not trying to be "mr know it all" just trying to help others become better informed

14* at redline will yield higher EGT's than 20* at the same load/rpm point since less of the burn is completed before teh exhaust valve begins to open. Meaning the manifold and tubro will be hotter, but internal temps won't change much

You are completely right. I don't understand how this is such a hard concept to grasp.

Hey Hakcenter If you would like to find some good tuning talk, check out EFI University - Electronic Fuel Injection Tuning, Training and Certification

[wishihadatalon]

Originally Posted by hakcenter

14* @ 7k rpm, that is where we are all talking about.

What your trying to say is that the gases are 100F - 300F degree's cooler because the explosion happens 8 degree's sooner ? That's a lot of temp for a small amount of duration.

Timing advance increases cylinder pressure, mostly from an entire burn, but somehow the burn being 8 degree's later, is hotter 4 inches away down in the header pipe because its burning up in the pipe as it passes ?

I'm not sold at all, I think something with the fuel atomization during high rpm is the culprit, and the end result being monitor'd istoo far away to register an accurate description of the AFR that really happened. If the AFR is the same, and timing is changed, I think retarded timing would have a more complete atomization, increasing overall heat instead of advanced timing, especially in the short duration that it happens in, in comparison between 8 degree's retarded.

Monster, what pump gas, 91 or 93 ? what % of corny goodness ?

I guess to be sold on this you should experiment with an egt gauge. Run low timing on a wot pull and monitor your egt's. Then start to add some advance, maybe all the way up to 18-20ish degrees on pump gas, and see what the egt gauge does.

One more thing to support this is the fact that other fuels burn slower and require more timing advance to properly burn and begin to extract more power out of your motor.

[turboglenn]

Originally Posted by wishihadatalon

I guess to be sold on this you should experiment with an egt gauge. Run low timing on a wot pull and monitor your egt's. Then start to add some advance, maybe all the way up to 18-20ish degrees on pump gas, and see what the egt gauge does.

One more thing to support this is the fact that other fuels burn slower and require more timing advance to properly burn and begin to extract more power out of your motor.

I have seen teh differences in EGT's due to timing changes. I have an EGT right on teh pillar, and with a full stand alone, my timing is where i program it to be..no fluctuations unless i program them in and the only one i have is to retard timing at super high temps ( or incase of a boost spike on my curretn street map ) I had higer EGT's when emulating a stock timing curve, they are quite a bit lower on my own timing map that i run now, i never get near 1600*F like some people say to tune to, and my AFR's are great

And you are correct, higher octane burns slower and has a higher flash point

[wishihadatalon]

Originally Posted by turboglenn

I have seen teh differences in EGT's due to timing changes. I have an EGT right on teh pillar, and with a full stand alone, my timing is where i program it to be..no fluctuations unless i program them in and the only one i have is to retard timing at super high temps ( or incase of a boost spike on my curretn street map ) I had higer EGT's when emulating a stock timing curve, they are quite a bit lower on my own timing map that i run now, i never get near 1600*F like some people say to tune to, and my AFR's are great

And you are correct, higher octane burns slower and has a higher flash point

I didn't quote you just so you know I agree with everything you are saying except for the way you tried to use the lower timing at lower rpms argument.

What standalone if you don't mind me asking?

[turboglenn]

Originally Posted by wishihadatalon

I didn't quote you just so you know I agree with everything you are saying except for the way you tried to use the lower timing at lower rpms argument.

What standalone if you don't mind me asking?

No worries, i wasn't taking it as any type of arguement. I was stating the timing drop at the beggining of a pull on the stock ECU just as a reference to show that retarded timing isn't going to melt stock internals.

AS for teh ECU, I use a Haltech E6k, very flexible, and will run anything from 1 to 16 cylinders. I use to be a dealer and north US tech support, but i gave that up several years back because I got out of the main import scene around here. Mainly because everyone talks sh!t and people/rich kids would come in asking "what should i do?? I want to make X amountn of power" and then after taking up hours of my time and me explaining what's good and what's not. They go off and buy teh shit on the "net.

So i work soley by reference of current clientel or if i know you i will do work for you, but no "walk ins" strangers etc... too much a pain in teh ass. I have 2 other businesses to run and that takes up enough of my time I mainly just subcontract my tuning abilities to some local shops and people that i know and help with their cars

[wishihadatalon]

Originally Posted by turboglenn

No worries, i wasn't taking it as any type of arguement. I was stating the timing drop at the beggining of a pull on the stock ECU just as a reference to show that retarded timing isn't going to melt stock internals.

AS for teh ECU, I use a Haltech E6k, very flexible, and will run anything from 1 to 16 cylinders. I use to be a dealer and north US tech support, but i gave that up several years back because I got out of the main import scene around here. Mainly because everyone talks sh!t and people/rich kids would come in asking "what should i do?? I want to make X amountn of power" and then after taking up hours of my time and me explaining what's good and what's not. They go off and buy teh shit on the "net.

So i work soley by reference of current clientel or if i know you i will do work for you, but no "walk ins" strangers etc... too much a pain in teh ass. I have 2 other businesses to run and that takes up enough of my time I mainly just subcontract my tuning abilities to some local shops and people that i know and help with their cars

Good stuff. I use Mega Squirt, not nearly as advanced, but still very potent and does everything that I could want it to do.

[hakcenter]

Don't insult me with a EFI learning website, not cool at all.

My motor had been recently rebuilt, all in spec, and a rock solid tune from 10psi to 15psi @ 10.5:1 17* advance @ 7k.

I wanted a bit more brang it up to 18psi and chopped 4* off and 2 pulls later bent #4 rod. During the entire life of that motor, there was never signs of pre-ignition, not even on the plugs, and I seriously seriously doubt, that I was ever making that much power, I would of expected more than 1 piston to go if that was the problem.

Anyways, when most of the flame ends up out in the manifold burning up, how does that help with emissions, or does a loaded respond differently with retard than no load at all ?

[dsm-onster]