7.5 AFR constistent @ WOT

[Warsteiner05]

Jet boat is back again, new engine, new turbos (twin 63/68 borg warners @ 18psi), new fuel system (Aeromotive Eliminator), pressure set at 60psi which is the same as before with no boost compensation. 80lb DEKA injetors, 5.3L with 853 heads.

My AFR on the wideband is a consistent 7.5 @ WOT. Black smoke like a diesel!

I'm new to HPTuners, I have read the tuning how-to's, but unsure of where to really start in the to get this SD tuned P01 ECM to lean out without doing major damage. Wideband only, no other O2 sensors as this is a BOAT with a jet drive. NO MAF, Basically tuning for WOT @ 6500rpm or cruising @ 3500-4000 rpm, no where in between. Cruising AFR is in the 14-15:1 range and currently ok with that. The major issue is the WOT AFR of 7.5:1 which as low as the wideband reads and there is a A LOT of power left on the table here. Tune file attached. No log file yet. Is there anything that really sticks out to you guys that I should adjust initially?

Jet boat tune download for HPT forum..hpt

[kevin87turbot]

It has a lot of commanded fuel in the VE table when in boost. Has this combo even ran correctly, or is it all new? What fuel are you running?

[Warsteiner05]

It has a lot of commanded fuel in the VE table when in boost. Has this combo even ran correctly, or is it all new? What fuel are you running?

(i'm very knowledgeable of combustion engine principles, I've built and service many drag cars and hot boats, I'm just not familiar with the HPTuners software!)

I bought the boat, ran it one time to find out it had a couple of dead cylinders, 1 burnt piston, and one bent intake valve. I discovered the fuel system was not up to par with the power potential of the setup. Had a new bottom end built, changed heads from 706 to 853 heads to lower compression a bit. New fuel system with 10an lines to aeromotive eliminator fuel pump, to regulator, 8an to 80lb deka injectors. 93 octane non-ethanol fuel.

My assumption is that they tuned WOT AFR to whatever the ideal chosen AFR was with the single smallish intank pump through 3/8's fuel lines. Now that I have proper fueling, and large lines, the AFR is FAT.

This is the tune that was in the boat when i purchased it. I'm just getting around to actually running the boat with everything working as it should. (All cylinders firing on good compression, correctly sized turbo's and fuel system)

Im sure I need to remove some fueling in the VE table when in boost, but how to you scale it all down as a single percentage, without having to change individual boxes?

Another question... I noticed all the tables are in kPa, is there a way to view them in PSI?

[curiousg7]

https://www.youtube.com/watch?v=vAQhoETdsRg

https://www.youtube.com/watch?v=U5-tP4pDtSY

Some handy vids on VE
Also is non boost compensated fpr a good idea? I'm still new but that seemed weird to me.

[Warsteiner05]

https://www.youtube.com/watch?v=vAQhoETdsRg

https://www.youtube.com/watch?v=U5-tP4pDtSY

Some handy vids on VE
Also is non boost compensated fpr a good idea? I'm still new but that seemed weird to me.

Thanks for the links! A huge beginner help lesson.

As far as the boost compensated FPR, Its an aeromotive with a boost reference port on top, but i've been directed by other tuners in the past to just leave the fuel pressure static as it makes it easier to tune. Is it needed at 30%-50% load at 4-psi-10psi??? Is it need at WOT @ 18-20psi? I do not know that yet, thats why I'm here! To learn!

When I had an boost compensating FPR on the last turbo truck I had (2006 silverado 1500 single 72mm 6.0) Nelson in Texas was doing my mail order tunes via data logging, and he ordered me to not use the boost reference port for the FPR. He said it was easier to tune with static fuel pressure.

[blindsquirrel]

That sounds backwards. With a referenced regulator the difference between the fuel pressure and manifold pressure is always the same. The same pressure delta. Thus the flow rate through the injector is always the same, and isn't increased by vacuum trying to suck more fuel out or decreased by boost trying to push it back into the rails. A tune file with a referenced regulator uses a flat injector flow rate table from one end to the other. With a non-referenced regulator the injector flow rate is constantly changing based on manifold pressure since fuel pressure is always the same.

Is it possible those other tuners had gotten lazy and were trying to use the injector flow rate table as a tuning aid? I mean, it's also easier to not worry about the VE table at all and just tune WOT AFR by fiddling the one simple straightforward PE table, and lots of tuners do it that way too (and it's wrong and lazy).

[curiousg7]

I would've thought boost referenced would be a lot easier, the tune you provided is actually set up that way. Flow rate is 98 in all cells.

[Warsteiner05]

I would've thought boost referenced would be a lot easier, the tune you provided is actually set up that way. Flow rate is 98 in all cells.

Thank you for showing me that! What exactly is the specific number "98" referring to?

The boat came with an in-tank pump and a corvette style filter/regulator.. it had no way of referencing boost for compensation. I didn't bother fooling with this to even see what it was capable of as I knew i would be far beyond the limits of 3/8's fuel line and the pump.

So apparently everyone is in agreement that I should run boost reference. I will run a line to the FPR before any further tuning or datalogging.

What is the concensus on a starting point for removing fuel from the entire VE table? 10% 15%? Or should I load a stock VE table and increase the percentage from there?

[blindsquirrel]

If you have a wideband and a way to get data from the wideband into the scanner, I think you should just log the EQ error and then apply that error data to the VE table. The amount of error is the amount in % that needs to be added or subtracted from those cells in the VE to make commanded match actual. You have these tools at your disposal so use them.

[curiousg7]

The 98 is lb/hr. In the editor if you hover over a button, in the bottom right it will show the units used for that table.

[5FDP]

If you removed 15% fuel in the area's it's in boost I bet the AFR's come way up where you want it too.

[kevin87turbot]

Just like 5FDP said...remove 15% fuel from the boosted area of your VE table to start with. After that, it should run much better at WOT. You can sneak up on it after doing that...maybe just take 4-5% at a time from the boosted area in order to achieve your target AF ratio.

Be careful with your max boost. You mentioned 18-20 psi max boost. That's not going to work on 93 octane gas. You'll be replacing more pistons at that level.

[Warsteiner05]

If you have a wideband and a way to get data from the wideband into the scanner, I think you should just log the EQ error and then apply that error data to the VE table. The amount of error is the amount in % that needs to be added or subtracted from those cells in the VE to make commanded match actual. You have these tools at your disposal so use them.

I have an Innovate LC-2. I also opted for the Pro feature set with the MPVI2. I just haven't hooked the wideband up to it yet. By hooking it to the scanner... this is what you mean correct? Sorry for being unfamiliar with what "EQ error" means!

[kevin87turbot]

The EQ ratio stands for Equivalency Ratio. It can be used to calculate WOT target AF ratio in many applications. If you click on the Fuel tab and click on the PE EQ ratio, you can see that yours has been set to 1.25. If you want to convert it to AF ratio, just divide your Stoich AF ratio by the EQ ratio. In your case, it's 14.63 divided by 1.25...which is 11.7:1 commanded AF ratio.

The EQ ratio error is the difference from the commanded to the actual AF ratio. You'll use the Wideband to determine the actual AF ratio.