ZL1 with an LT1/LT5 cam

[ZLRob]

I inquired about this setup some time ago in order to stay relatively compliant and trouble free within my state. I would had liked to go with a legit custom grind or a PD cam of some sort, but my hands are/ were mostly tied if I want to keep the car registerable. Fast forward to now and here we are. LT4 has been fitted with the DOD delete cam and the benefit of a 32% fuel lobe and we are up and running! Car seems to like the cam for the most part. I'm trying to figure out my limitations, however, and while I'm rocking a 5% overdrive lower pulley I have a 12% from when I first got the car. I used to run 27* of timing at WOT, but with this new setup I backed it off to 24* as per the advice of someone who helped me set up my tune initially at the time. I don't know if that is/ was necessary, however. I'm also trying to determine if it's even worth running a larger pulley if it's going to exceed the 20,000 RPM limitations of the supercharger drive idler bearings. Would someone be willing to take a look at my tune and tell me how I'm looking and entertain all of my new curiosities regarding the setup?

Mods are as follows:
- Flex fuel (currently E50- E60 before running overdrive fuel lobe)
- JMS BaP
- 5% ATI supercharger pulley (12% on standby and ready if need be)
- Secondary cat delete/ full exhaust post primaries
- Granatelli SS wires
- LT1/5 cam with 32% lobe
- DOD delete
- Katech oil pump
- Heat Range 7 95605 NGK Ruthenium plugs
- Cordes LTR reservoir
- Water Wetter

Attachment 130962
Attachment 130963

[GHuggins]

I haven't looked at the tune, but you might want to play with soi just a little to see if you can get your pulsewidth down. Was very surprised you didn't gain any boost. Guess the 117LSA helped out more than I thought it would.

How is it performing compared to the old cam? Sounds like it's noticeable?

Cam's usually like timing and with your airmass staying at 1.3, I'd say start creeping it up a little. Think she'll do just fine with it.

[ZLRob]

I haven't looked at the tune, but you might want to play with soi just a little to see if you can get your pulsewidth down. Was very surprised you didn't gain any boost. Guess the 117LSA helped out more than I thought it would.

How is it performing compared to the old cam? Sounds like it's noticeable?

Cam's usually like timing and with your airmass staying at 1.3, I'd say start creeping it up a little. Think she'll do just fine with it.

I'm actually a bit surprised I didn't lose any boost actually considering the durations are a bit longer than previously. Normally, from what i have found, increased airflow causes a drop in boost. I was actually considering that because I did notice the PWM was a bit high indeed. Will there be any benefit in changing the SOI/ EOI as far as power is concerned? Regardless, I did notice that the PWM went down a little bit compared to what they were previously under a full gun pull.

My airmass used to be higher on the LT4 cam. I'm guessing this thing is going to need some tweaking in order to get it to run at its peak? With a degree or two of timing, I should be fine yeah?

[GHuggins]

The exhaust side being downgraded is why I thought it would gain and not lose - probably why airmass is down too - not flowing quite as good there. Intake side usually doesn't matter a whole lot. Actually really surprised it stayed the same.

As long as you can change the soi to actually lower pulsewidth - usually a lower number up top - then you should actually possibly gain some power.

Timing wise - just ease it up after getting fueling right. Keep knock settings near stock to begin with and go a little at a time. Couple of degrees should be fine.

[ZLRob]

The exhaust side being downgraded is why I thought it would gain and not lose - probably why airmass is down too - not flowing quite as good there. Intake side usually doesn't matter a whole lot. Actually really surprised it stayed the same.

As long as you can change the soi to actually lower pulsewidth - usually a lower number up top - then you should actually possibly gain some power.

Timing wise - just ease it up after getting fueling right. Keep knock settings near stock to begin with and go a little at a time. Couple of degrees should be fine.

Did you get a chance to look at the log? I am more on the novice side of tuning and am not too informed on what SOI and EOI necessarily does. I am aware of it's function, but have a limited understanding on how it would impact things as far as runnability goes.

Is this thing worth modding over a 12% overdrive to bring it's power up and how much ethanol do you think I could run this way? I currently run E50-60 but that was before the 32% fuel lobe.

[GHuggins]

Goal is to lower soi - start of injection - making it inject closer to tdc compression - if able to do so you should see it go richer and allow you to pull fuel/air out of the MAF curve. In doing so it will allow more headroom for more boost or ethanol - that's if it works out and a lot of the times with the lobe it actually does quite well. Pull 20 to see what happens and keep an eye on knock and afr/lambda readouts. If knock starts, then you may have to keep it like it is. You can also raise rail, but don't go over 21mpa. Injectors start sticking around 22mpa on some of the lt4's.

[ZLRob]

Goal is to lower soi - start of injection - making it inject closer to tdc compression - if able to do so you should see it go richer and allow you to pull fuel/air out of the MAF curve. In doing so it will allow more headroom for more boost or ethanol - that's if it works out and a lot of the times with the lobe it actually does quite well. Pull 20 to see what happens and keep an eye on knock and afr/lambda readouts. If knock starts, then you may have to keep it like it is. You can also raise rail, but don't go over 21mpa. Injectors start sticking around 22mpa on some of the lt4's.

I raised the desired rail pressure to 3050 psi and I'll see how it reacts to that. I have to drive the car today anyway so I should be able to get a decent log.

Where exactly should I pull 20 out of on the SOI? On the entire table, or on a certain area?

Given the mods would you say it's safe to try and dump in a full tank of E without it being mixed now? The typical E content here is around 76% as an FYI.

[GHuggins]

High rpm and full load - lower right corner area - start around 4000 rpms, smooth it all out so transitions smooth and see how it reacts. Don't do E until you have gas right. If you start experiencing random fuel cuts/phantom rev limiter, then lower rail pressure as injectors are sticking shut.

[ZLRob]

High rpm and full load - lower right corner area - start around 4000 rpms, smooth it all out so transitions smooth and see how it reacts. Don't do E until you have gas right. If you start experiencing random fuel cuts/phantom rev limiter, then lower rail pressure as injectors are sticking shut.

Am I smoothing or interpolating? Full selection or between vertical or horizontal bounds? Also you are recommending I touch just SOI base and not another one of the selections correct?

I am already running E50 as of current. As this was how my setup was before all the work was done.

[GHuggins]

Smooth into the area where you removed it. Lower right corner should be high load, high rpm from the number table - you can look at the axis. This will be the highest numbers in the table.

I would highly advise that you go back to gas, tune that back in and then go to alcohol in stages tuning it back in correctly. That's the only way to do it right.

[ZLRob]

Smooth into the area where you removed it. Lower right corner should be high load, high rpm from the number table - you can look at the axis. This will be the highest numbers in the table.

I would highly advise that you go back to gas, tune that back in and then go to alcohol in stages tuning it back in correctly. That's the only way to do it right.

Managed to get it nailed down last night and took it out for a spin today. I'm seeing different SOI peak nominal numbers down in the high 330's but INJ PW's have not changed around WOT. Total duty cycle has stayed around 25.7% just as it did in the last log. One of the guys on here has been helping me out and when we were looking at his a while back because he had abnormally high PW's we changed the EOI instead and that seemed to help lower his PW's apparently. Should I be looking at that instead?

[GHuggins]

Your talking about split base? You can try. It's usually only used for cranking. Unless your talking about the main eoi number that defines the maximum time the injector can spray?

Soi will change eoi regardless, but you can always try the others. I remember the split base doing something...

[ZLRob]

Your talking about split base? You can try. It's usually only used for cranking. Unless your talking about the main eoi number that defines the maximum time the injector can spray?

Soi will change eoi regardless, but you can always try the others. I remember the split base doing something...

Yeah, the EOI split base tables. You are right though in the fact that the PW is a bit high considering what's been done to it. I don't disagree at all. Is there another EOI table I should be looking at?

What is the maximum injector DC that these LT4 injectors top out at? I was told it was somewhere around the mid 30's if I recall correctly.

[ZLRob]

Okay so here's some feedback after making some changes:

I initially ran an SOI of 330 as per your suggestion, that netted no positive changes and if I recall correctly I actually got hurt by that and wound up seeing lean activity on the higher side of .87-.89 lambda at WOT so I reverted back to the stock tables. and everything cleaned up.

I went full send and put in a full unmolested tank of E85 direct from the pump into the car to see what sort of results I'd get out of that. Just as I expected I saw an alcohol content of 75-76% right on the money like I anticipated. Cool.

I went ahead and started playing with the SOI tables again and gave it a high end of 388.1 on the tables set to 350 and smoothed them out to find a more gradual climb to my defined parameters. Without modifying the SOI alcohol tables I found a high end of 407 on my WOT and a lean activity of .87-.89 on my AFR, so I retained my tables and zeroed out the alcohol adder SOI table. Found a new high end SOI of 396 while under full gun and lambda remained the same. Still lean, so some changes needed to be made yet again.

After these runs I reverted back to stock tables, but I used the C7 ZR1 tables since this cam is the closest to the one on the Vette as far as specs are concerned. Lambda under full gun went back to .83-.85 as they originally were with a maximum PW of 5.4-5.5. Max SOI was in the range of 366 and EOI was in the range of 170 at 6000 RPM which swung to a low range of 150 up to redline. Low side was between 74-78 PSI and high side swung between 2800-3000 throughout the entire range. Torque also went up from 612 to 624 ft. lbs. at around 3400 RPM so everything appears peachy for the moment.

I feel like the VVE tables may need some modification, or perhaps some smoothing at the very least? I could be wrong but I feel like I'm potentially missing out on some power here. The good news is that with my current setup I am 100% confirmed good to go to run fully unmixed ethanol direct from gas station pumps now so that is really cool. Should I explore the larger pulley or should I leave well enough be, as I assume that will obviously raise PW's after the MAF gets rescaled to reflect the amount of fuel needed to match the new amount of air and boost coming in, Opinions?

LT5 cam full ethanol WOT run(1).hpl