FlexFuel and Highside pump supply...

[2023_ZL1-AUTO]

I tried to get info on this else where but no response yet. So I'll ask the tuners here! For my 2023 ZL1 A10, I both the DSX Flex Fuel kit and the JMS Fuel Max Booster kit (and will be getting a Flex Fuel tune as well). But, I'm wondering where the issues start showing up related to not enough high side fuel pressure. If I understand it right, that's where the issues are related to running a mix or straight flex fuel. I've attached two HPTuners data logs and have highlighted the fuel PSI etc. They both show demand and the actual when running 93 octane (no flex fuel). My question is: Is there a way to determine from the data logs attached, if my high side fuel pressure will be sustainable based on the demand request once I mix in flex fuel? In other words, I'm trying to determine what Fuel PSI is required to run say E30 to E60+. I do have the JMS Fuel MAX system and will install it, but I'm curious at what point do you see your running out of pump vs having enough when mixing in flex fuel?

mexico_pull_01.JPGmexico_pull_02.JPG

[TriPinTaZ]

You want to maintain 70-80 psi on the low side and 2900 on the high side. If the low side drops, the high side drops. The JMS will keep the low side good and give the high side a little more room. But the improvement isn't a lot. Next the high side will drop regardless of the low side sustaining 80 psi.


The limit is actually the injection window SOI and EOI. With higher pressures, the injectors spray more fuel in the window. If pressures drop and the injectors stay open longer, or the injectors stay open longer and causes the pressure to drop (sort of go hand in hand), then you run out of injection window.


What mods do you have and where to do you (altitude)? There is a lot of info out there on the ballpark capacity based on mods. If you're bone stock, you can probably run Pump E (E70-E80) with the JMS until Winter. Once the temps drop and the car makes more boost, you might have to mix down.

[2023_ZL1-AUTO]

Hey! Thanks for he reply ! That's good info... I often confused the low side vs the high side. These are my current mods and yes the car is tuned: 2" headers, ultra flow CATs, stock X-Pipe, my axle back was the Corsa Xtreme NPP (just replaced it with the Stainless Works Legend Axle back), 100mm Soler throttle body, Big Gulp, Granatelli Malevolent coil packs, Granatelli custom zero Ohm wires, NGK Iridium IX plugs, iBanks Data Monster and AEM ARF Wideband.

[Joshinator99]

You want to maintain 70-80 psi on the low side and 2900 on the high side. If the low side drops, the high side drops. The JMS will keep the low side good and give the high side a little more room. But the improvement isn't a lot. Next the high side will drop regardless of the low side sustaining 80 psi.


The limit is actually the injection window SOI and EOI. With higher pressures, the injectors spray more fuel in the window. If pressures drop and the injectors stay open longer, or the injectors stay open longer and causes the pressure to drop (sort of go hand in hand), then you run out of injection window.


What mods do you have and where to do you (altitude)? There is a lot of info out there
on the ballpark capacity based on mods. If you're bone stock, you can probably run Pump E (E70-E80) with the JMS until Winter. Once the temps drop and the car makes more boost, you might have to mix down.

Hey! Thanks for he reply ! That's good info... I often confused the low side vs the high side. These are my current mods and yes the car is tuned: 2" headers, ultra flow CATs, stock X-Pipe, my axle back was the Corsa Xtreme NPP (just replaced it with the Stainless Works Legend Axle back), 100mm Soler throttle body, Big Gulp, Granatelli Malevolent coil packs, Granatelli custom zero Ohm wires, NGK Iridium IX plugs, iBanks Data Monster and AEM ARF Wideband.

Jason is spot on as always.

OP: with your mods you’re not going very far with E. You’ll need a cam with a bigger fuel lobe at some point soon if you try to up the boost or run high amounts of E. Start with E30 and see how it goes. You need to data log:
1. Low side commanded & actual fuel pressures
2. High side (rail) commanded & actual fuel pressures
3. Injector pulse width. Times over 6.0ms are a recipe for disaster.

You can make good power DI only but it’s expensive. My power level is in my signature and it’s all DI but was a $10K investment to do just that. Port injection has come way down in cost using the TooHighPSI setup so you may want to give that some thought.

[TriPinTaZ]

Yup I would start at E30 and see how far you get. I would guess you will be in the ballpark of E50, maybe a little more with the JMS.

[2023_ZL1-AUTO]

OK - So I know that a CAM is the ultimate way to go, that would also probably end up being a Stage 3 or Stage 4 package as well. I'm torn between changing the stock car so much (touching oil) that it may effect the resell value down the road (even thought that isn't my biggest concern). I could budget the $$ for mods, that's not an issue. Seems like there isn't an option to just "add a CAM", then your talking spring, push rods, maybe rockers? and valve covers depending on clearance? But then you kind of can't stop there if you have it that torn down, right! So then your probably adding an ATI Harmonic balancer, probably a Magnuson 2650, a new 103mm TB etc etc... So if I add a CAM, I'll go the route of a stage 3 or stage 4 package a builder offers! So, would you conclude or is your opinion that : The over all HP gain I'd get just by adding the DSX FF kit and the JMS isn't worth, what would that HP be 10, 20, 50, 100? I'd like to find a local dyno to get numbers on my ZL1, but that's proving to be more difficult than you would think! But what could I actually gain is the questions with FlexFlue vs CAM and a package etc and then is it worth to time and effort, I already have the parts so that isn't an issue! Thanks for putting up with my ignorance on this subject!

[TriPinTaZ]

Your best bang for the buck is intake, headers, 2.3 upper, JMS or DSX lowside(JMS can handle these mods), and Flex Fuel. You can probably run E40-E50 with this setup. The next step forward involves deciding on fuel mods. Meth is the cheapest but also the most unreliable option. Not to say it is unreliable.....but if something happens with the meth, you risk popping the motor.

IMO a 2650 isn't worth it unless you're doing heads and cam package. The 2650's improvement in power over an X port stock blower, isn't worth the $$$$ without adding additional airflow capacity with ported heads and a bigger cam.

[Joshinator99]

OK - So I know that a CAM is the ultimate way to go, that would also probably end up being a Stage 3 or Stage 4 package as well. I'm torn between changing the stock car so much (touching oil) that it may effect the resell value down the road (even thought that isn't my biggest concern). I could budget the $$ for mods, that's not an issue. Seems like there isn't an option to just "add a CAM", then your talking spring, push rods, maybe rockers? and valve covers depending on clearance? But then you kind of can't stop there if you have it that torn down, right! So then your probably adding an ATI Harmonic balancer, probably a Magnuson 2650, a new 103mm TB etc etc... So if I add a CAM, I'll go the route of a stage 3 or stage 4 package a builder offers! So, would you conclude or is your opinion that : The over all HP gain I'd get just by adding the DSX FF kit and the JMS isn't worth, what would that HP be 10, 20, 50, 100? I'd like to find a local dyno to get numbers on my ZL1, but that's proving to be more difficult than you would think! But what could I actually gain is the questions with FlexFlue vs CAM and a package etc and then is it worth to time and effort, I already have the parts so that isn't an issue! Thanks for putting up with my ignorance on this subject!

The port injection option lets you add all the fuel you need without having to do a cam or having to open the engine. Food for thought.

[TriPinTaZ]

The port injection option lets you add all the fuel you need without having to do a cam or having to open the engine. Food for thought.

Yup port injection is awesome. I recently tuned an LT4 with the port kit on it, running full E and a 2650 bower, no issues. Car needs ported heads though. Plenty of fueling room left for heads and cam which is the next step.

[2023_ZL1-AUTO]

ok thanks everyone !!!! This is good info... I will add the dsx and the jms today and then maybe look at a port kit setup !!!!

[2023_ZL1-AUTO]

OK, along with the install of the JMS Fuel MAX v2 ... I want to tap in to the fuel pump hot wire (Fuse #35) in the trunk but have no idea which wire it is or how to find it. I'd much rather tap in to a wire that's 2 feet away and unobstructed vs a buried up behind the differential would be much easier! Any info would be greatly appreciated! Thanks !!!!

Edit: Additional (2) photos, So I guess the instructions show to tap and connect the wire over at the black plastic junction box things that's over on the drivers side of the trunk wall, and not at the fuse box. Thus, I assume the connection the instructions shows (being held in hand), is under the plastic cover near where I mounted the JMS?

Edit it #2: Looks like the Lingenfelter instructions are much more clear for their version of the voltage pump booter, and they identify the correct wire! But I assume I'm getting the wire location from Step 24 as I assume my ZL1 falls under this statement: "Vehicles that are equipped with the electronic axle positraction-limited slip differential (G96) please skip to step 24."

Screenshot 2023-07-29 200604.jpg

[2023_ZL1-AUTO]

scrap the above post, as it looks like I'll need to go to the connection under the car as the fuel pump hot wire in the fuse box seems really thin (small gauge) compared to that of the jms wires. i was hoping to avoid running the wires and splicing under the car but will do my best! I'll look for connectors that I can use to secure a good connection and not cut any factory wires as the next person, if there is one! might want to remove. I kept all my stock parts so if I get rid of the car all the parts can go wit hit !

[TriPinTaZ]

You will want to tap closest to the FPCM as possible and not the fuse box.

[ochoa121805]

Yup port injection is awesome. I recently tuned an LT4 with the port kit on it, running full E and a 2650 bower, no issues. Car needs ported heads though. Plenty of fueling room left for heads and cam which is the next step.

Wondering if this is mine

If so , yes heads and cam is definitely the next step


Thanks again Jason .

[TriPinTaZ]

Wondering if this is mine

If so , yes heads and cam is definitely the next step


Thanks again Jason .

Just might be lol

[2023_ZL1-AUTO]

You will want to tap closest to the FPCM as possible and not the fuse box.

" scrap the above post, as it looks like I'll need to go to the connection under the car " Yep !! I realized that after I saw the wire size difference between the two. I'm having a fit removing the connector. I pushed the red clip upwards as far as it will go, but I'm struggle to get the connect to come off. Is it the green circle area need pushed in as the connected is being pulled off/out? Thanks!!!

[2023_ZL1-AUTO]

I was finally able to get the connector loose and waiting for confirmation of what wire I'm splicing into. I think on the 2023 ZL1 it's the Red with Purple tracer. Also, I looked in the repository but either don't know how to search for what I'm looking for, or it was not there. Is there a tune file to use as a basis for Flex Fuel on a 6th Gen ZL1 automatic (2023)? I'm doing the obvious setting changes. But, I know I will need to change the Alcohol Spark table as mine is 100% all ZEROs (I think these are adds/subtracts to the main gas spark table, but I am probably wrong), and not sure what else is essential to change. Thanks for any assistance!

[2023_ZL1-AUTO]

Also looking at tune file and making these changes for the Flex Fuel options. If anything stands out as total wrong or something I missed, I'd appreciate if someone can point it out! I grabbed different video and followed a few tuners, goatrope and outlaw camaro, i hope this works just to get me started. I will get my tuner to do the actual tune once I see it's all working etc. Thanks again !!!