LSJ Turbo MAF tuning

ccannx

Goblin Guru
I could use more eyes on my attempt to tune the MAF.

Going from the K04 turbo to the ZFR 6758 Ilso replaced the LSJ intake manifold with the OTTP intake manifold and a small inline water to air that runs off the existing lsj intercooler setup.

I started by increasing fuel by 15% on the MAF table then made a easy short run with LTFT reset and LTFT STFT off through the VCM scanner functions. Made several adjustments to the maf curve and had to add a lot of fuel up higher where the K04 was not pushing boost at higher RPM.

what interesting is how nice idle looks with the STFT's off but the log afterwards where the STFT's are allowed to make changes the throttle has a small idle hunt loop. You can see the spark changing as it pulls fuel and lets it back in.
 

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Gtstorey

Goblin Guru
Changing the map sensor settings is easy, assuming it's the same as the LNF. I think it's pretty common across all platforms.

Your idle issue may be similar to mine and may be caused by the spark change instead of the spark being a reaction to the idle. You may want to lock the spark (and cam if it's variable) down in the idle rpms, at least until you get the maf tuned. At least that is what I found recommended on HPT forum. I'll see how well it works on mine this weekend.

I'm definitely a novice tuner, but I'll try and look at your tune and see if anything jumps out at me this evening.
 

Gtstorey

Goblin Guru
Reading through you link on the MAP change, it is a lot different going to the 3 bar map sensor on the LSJ than the LNF. Are you expecting that much boost or will a 2.5 bar work?
 

ccannx

Goblin Guru
Reading through you link on the MAP change, it is a lot different going to the 3 bar map sensor on the LSJ than the LNF. Are you expecting that much boost or will a 2.5 bar work?
I may go up to 25 psi down the road. I read that a 3 bar sensor only actually can read 2 bar of boost I think this may be due to 1 bar measured at vacuum inside the intake manifold. So a 2.5 bar 14.696 x 2.5 - 14.696 = 22.044 psi max readable so the ecu would not be able to compensate for any boost spikes over that. map explanation link
 

Ross

Goblin Guru
That looks like my P12 tables. Sorry, last time you posted, I assumed you had LNF tables.
I see you have the voltage multiplier table set to 1.7x What injectors are you using?
I am still wrapping my head around how I am going to tune for my Bosch EV14 82lb/hr injectors on the P12 PCM.
It is an early ECM for programming, and has a few limitations.

P12 issues:
1: The injector flow rate vs KPA intake pressure table doesn't work above 62.5lbs/hour injectors.
2: The voltage multiplier table doesn't get arount limitation #1. So if the total after the multiplier is above 62.5, it hits the upper limit.
3: The injector offset tables use exactly 50% of the offset values.

Since you have (and many people have) set the multiplier higher, you basically have hit the limit, and have been able to get your engine to run by making up for it in the MAF Calibration and Main VE tables. Post#56 by armcclure.

This thread talks about getting the Bosch EV14 60lb/hr injectors on a P12 PCM.
Post #44: armcclure says:
it's MUCH easier and equally as effective to simply use a factor of 2. As in cut the ifr values for the specific injector in half (assuming they're smaller than 127#), and either double stoich or cut maf/ve in half and fine tune. I tried the stoich method and had cranking fuel issues, so I simply reverted back to the scaled airflow. The only catch is any table that uses airflow as an axis needs rescaled also, but that's pretty simple.

The armcclure method has issues too, as not all tables are available thru HPTuners to rescale the airflow.

Post #50, Speedytec says:
So that's why I changed my fuel regulator for a 3.0 bar Saab version and I don't have to scale anything for these Bosch injectors.
And my idle and transient behaviour is pretty good with these.

My stock fuel pump & regulator are giving me 60 PSI fuel pressure, which is 4 BAR, or 3 BAR above atmospheric. I'm not sure how Speedytec is tricking the P12 to give more fuel.
 

ccannx

Goblin Guru
I see you have the voltage multiplier table set to 1.7x What injectors are you using? Siemens 80# injectors from ZZP

I believe the injector values 80# in this tune are from Al

Post #50, Speedytec says:
So that's why I changed my fuel regulator for a 3.0 bar Saab version~

Is that why guys are going to the boost reference fuel system ? Is it a regulator that connects to a boost port and adjust pressure ouput according to the pressure in the cylinder while the injector is open ?
 

Ross

Goblin Guru
A boost reference fuel regulator will keep the fuel pressure a fixed PSI above the intake manifold pressure.
Example: at idle, the intake is at 10 PSI, the fuel is at say 50PSI. Under boost the intake might be at 35PSI, the fuel is at 75PSI.
The benefit of this is less fuel delivery at idle, allowing big injectors to acheive idle, but also allowing them to supply lots of fuel under boost.

I am on a full stock SC LSJ. But I want to put in my Bosch EV14 82lb/hr injectors, just haven't figured out the tune for them.
 

ccannx

Goblin Guru
Went ahead and ordered the Zzp brfps . Looks like its a pretty simple solution that uses intake manifold vacuum to lower pressure to help alleviate big injector idle issues and raise pressure during boost. Hopefully this will help keep my maf cells populated with VCM scanner more stable.

It appears we have a regulator in the fuel pump that needs to be disabled for the external regulator to work correctly. I will probably order an ecu recalibration from Zzp to get my injector values correct afterwards so I dont mess something up...

FROM Zzp's website :

Manifold regulated fuel pressure:
For this installation method, the factory in canister regulator is bypassed. This requires dropping the tank and bypassing the factory 60psi regulator. When the canister is removed, open the canister and clip off zip ties holding the clips on the regulator. Now open the regulator to expose ball and spring tab, next remove ball and spring tab, then clip fuel diverter back on and re-install canister.
 
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Ross

Goblin Guru
That boost reference fuel regulator looks like a nice option. I didn't know you could use the stock fuel pump. I'm curious how it will install, and how well it will work after it is all installed. Looks like it needs the "Injector Flow Rate vs. KPA VAC" table modified. Unfortunately this table only goes up to 11.6 PSI. Weird that HP Tuners names the table with KPA (metric kilopascals) but then uses PSI (imperial pounds per square inch) units in the table.
 

Gtstorey

Goblin Guru
I thought I posted the below earlier in the week, but it's still here in the reply box. Not much help but I did look at it.

I obviously don’t know enough about the lsj tuning to comment much. About all I can say is that maybe you need a few more iterations of maf tuning to get it closer. Your timing is much smoother than mine on idle.

I did notice that your acceleration pedal position hit over 200% when you got on it hard. Might be nothing but looks strange to me.
 
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