Piston faliure 6.2 whipple 7psi

[nkautz]

It's too bad you don't have the tune file to share. I'll bet KR was not pulling enough or completely disabled.

[GHuggins]

why? Who decided that 11.5-11.7 is the best? The internet.....the reality is that much of the additional fuel (above what you would consider reasonable for a NA motor) is for cooling. DI blows un-vaporized fuel right into the chamber where it has a tremendous capability to quench (cool) the combustion temps. This allows the ability to run a leaner AFR then what we are used to in port fuel engines..

The bottom line is there is a range that engines like to run at for good power but there are many factors that can effect what is really the best. Different fuels react differently, as well as how efficient a combustion chamber works. The GEN5 cylinder head is very efficient which is another reason you can run leaner. Unless you can spend enough quality time on a dyno its hard to find this.

Higgs,

The injection timing strategy with this controller is much more complex then what we have available with the current tables. We are getting ready to test an engine in which we installed EGT probes which will really give is some insight as to what direction we should be going and why. As stated earlier even the WB is not telling us the full story when it comes to what is going on it the chamber. EGT's will offer another "dimension" into what's happening. The math is driving me nuts as there has to be some other factors that offset timing based upon airflow changes.

I'm still wondering if your LT4 fuel hardware changes require more that is in a LT4 OS that is causing some of your issues....

Really stupid question I'm sure, but what would everyone on here consider a safe EGT for DI or any gas motor? I've always believed in plug reading. Probably shoot way too rich with my own readings. I like to see a nice "darkish" brown color on my plugs and in the combustion chambers or at least the valves durring re-inspection tear downs. Guess I air too much to caution, but doing it this way gets me the same power on a hot motor as it does on a colder motor. Then as of now I've just been adjusting injection timing for "fuel useage" optimization. Just figured this was showing the most efficiency? I know it's not precise and could be adjusted better, so I'm really curious on "goaled" EGT's...

Thanks

[nkautz]

Good question , haven't explored EGT's yet. I've heard 1500-1700, but what puzzles me is that I read going too lean can cause EGT to drop.... I would think that would produce more heat and higher egt

[Redline MS]

Really stupid question I'm sure, but what would everyone on here consider a safe EGT for DI or any gas motor? I've always believed in plug reading. Probably shoot way too rich with my own readings. I like to see a nice "darkish" brown color on my plugs and in the combustion chambers or at least the valves durring re-inspection tear downs. Guess I air too much to caution, but doing it this way gets me the same power on a hot motor as it does on a colder motor. Then as of now I've just been adjusting injection timing for "fuel useage" optimization. Just figured this was showing the most efficiency? I know it's not precise and could be adjusted better, so I'm really curious on "goaled" EGT's...

Thanks

Plug reading may be fine for WOT but part throttle not going to happen. The proper way to read a plug is to go WOT, shut the motor off and check. Driving around and then looking at a plug in a closed loop fueling system is hard to quantify anything. The EGT reading is to be combined with lambda. You can have EGT's to the extreme of rich and the extreme of lean so you need to have another "check" to ensure this. Much of what drives MAX EGT is the parts....at some point aluminum melts....that's to hot! If I had to stab a temp range it would be between 1100-1300 but again much like spark timing and fueling its dependent on many other factors.

As we have discussed in prior threads; if you air model is correct and your injector data is correct, its still possible to have the wrong AFR due to injection timing. DI is so prone to poor cylinder mixing (when SOI is off) that your "reported" AFR can swing rich very quickly which would normally have you change your air model to solve. Not only is this a problem in fueling but since the torque model is tied to airflow you just messed that up to.

Regarding the plug reading; the real reading is down in the base of the plug. We have a tool that cuts the threads off the plug to get to it and we mostly look at it to see where we are on timing.

[nkautz]

Plug reading may be fine for WOT but part throttle not going to happen. The proper way to read a plug is to go WOT, shut the motor off and check. Driving around and then looking at a plug in a closed loop fueling system is hard to quantify anything. The EGT reading is to be combined with lambda. You can have EGT's to the extreme of rich and the extreme of lean so you need to have another "check" to ensure this. Much of what drives MAX EGT is the parts....at some point aluminum melts....that's to hot! If I had to stab a temp range it would be between 1100-1300 but again much like spark timing and fueling its dependent on many other factors.

As we have discussed in prior threads; if you air model is correct and your injector data is correct, its still possible to have the wrong AFR due to injection timing. DI is so prone to poor cylinder mixing (when SOI is off) that your "reported" AFR can swing rich very quickly which would normally have you change your air model to solve. Not only is this a problem in fueling but since the torque model is tied to airflow you just messed that up to.

Regarding the plug reading; the real reading is down in the base of the plug. We have a tool that cuts the threads off the plug to get to it and we mostly look at it to see where we are on timing.

Yes , I only use plug reading for wot. Checking the annealing point on the ground strap has been incredibly useful and is so easy to do. It's basically telling you , this is the peak cumulative combustion temperature that was reached during the pull. Too high and you start to melt things , too low and you can turn it up more. However , I've chased my tail before thinking I had gone too far when in actuality the annealing point hadn't even started to show yet. It takes a some getting used to and different brand plugs will show different color markings.

[Nick@Newtech]

It definitely looks like the lt1 has inherited the weak rear cylinders of the ten IV and III, I would be nice if gm had a coolant crossovers like the 97-98 motors had. There are aftermarket solutions.

[nkautz]

It definitely looks like the lt1 has inherited the weak rear cylinders of the ten IV and III, I would be nice if gm had a coolant crossovers like the 97-98 motors had. There are aftermarket solutions.

Did they do away with the rear crossover because the intake manifold is in the way?

[Nick@Newtech]

Yup

[Redline MS]

It definitely looks like the lt1 has inherited the weak rear cylinders of the ten IV and III, I would be nice if gm had a coolant crossovers like the 97-98 motors had. There are aftermarket solutions.

Hard to believe that they still haven't addressed these things.

[LSxpwrdZ]

The key is to use ALL of the sources of good data you have available to give yourself the intel to make a decision on what to do next. Does it need more timing, more fuel, less timing, less fuel, more cam advance/retard, more/less SOI timing etc.

You leave data on the table if you don't look at the plugs especially from the problematic/hot cylinders of the engine. This is obviously with fresh plugs and WOT pulls and shut down only. I've seen physical signs of detonation on plugs that the knock sensors didn't pickup. Which do you believe at that point? Like I said you have to take a total grasp of all the data to determine what the best course of action is to move forward with the calibration.

[rynez06]

the OP mentioned 15 degrees at WOT.... like a block of 15 degrees? or 15 degrees at peak power? i've tuned quite a bit of gen 5's now and having a block of 15 degrees would definitely be an issue, especially down low and through peak tq in a 5000+ lb truck. what did the timing curve look like?

[trunks604]

I work on lots of these engines and even stock it happens in number 8 ... ive seen the piston in the bottom of the pan. Ford will warranty this as defective.

[AutoWiz]

Just thought i'd post up a picture from the matrix. rofl. for all of your enjoyments..

[nkautz]

Just thought i'd post up a picture from the matrix. rofl. for all of your enjoyments..

No one likes a showoff, lol.

20151108_192442.jpg

[AutoWiz]

I understand and agree that hptuners has a nice gui, but honestly, don't you think that video card is a bit overkill for hptuners?

[nkautz]

I understand and agree that hptuners has a nice gui, but honestly, don't you think that video card is a bit overkill for hptuners?

Overkill? Never heard of it.

[bearcat]

it would be nice if they made spark plugs with egt in them for tuning.and a vibe transducer for each cylinder.
some good info here thanks

[GrannySShifting]

It definitely looks like the lt1 has inherited the weak rear cylinders of the ten IV and III, I would be nice if gm had a coolant crossovers like the 97-98 motors had. There are aftermarket solutions.

That doesnt "fix" the back cylinders dying first. Ive seen just as many LS1 coolant crosssover cars melt the back two holes as the rest of them

[Nick@Newtech]

That doesnt "fix" the back cylinders dying first. Ive seen just as many LS1 coolant crosssover cars melt the back two holes as the rest of them

I agree its not a fix but it seems to help keep things more even. Doing a plug read after a pull on the dyno you can see the timing strap seems to be farther down on the rear cylinders than the front cylinders, on the flip side of that I have seen the exact opposite on various setups. Only other things i can think of would be distribution of air mass and or fuel, something a lot of tuners don't think of also is spark advance is usually global value, whats good for some cylinders are not good for others. this ultimately is what kills the one or two cylinders and the rest are fine.

[veee8]

You can dial timing up or down on individual cylinders vs. rpm in the Static Retard table.