John Speake

Hello Brian
"WOT" is registered when a switch in the throttle switch assembly makes contact when the throttle plate is about 2/3 open. It doesn't have a "click" like the closed throttle switch ("idle" switch) because it is not a nice microswitch like the idle switch, just a pair of springy contacts..

The LH also goes off loop when

1) Water temp is below normal operating temp. This is because the engine would not run when cold if A/F was stoich.

2) When you hit the throttle quickly, the LH goes off loop to give the transient mixture enrichment necessary to prevent the engine leaning out and "stumbling". The LH registers the rate of change of the MAF output voltage to detect this.

Hope this helps ?

Louie928

Hi Tony,
The LH interpolates between the RPM numbers. That's true on the base map where it interpolates between load values too. On your WOT map, 3700 is zero and 4800 is 12. That's an eleven hundred RPM increment. Halfway in between (4250 RPM) would get you an enrichment of 6. That makes it not as bad as it initially seems. Agreed, user changeable RPM numbers would be nice especially when tuning near idle on the base map.

John Speake

This is to announce that the User Manual for the LH2.2 SharkTuner for the 85/86 early US 32v and also the Euro 16v is available for down load from my website.

Go to the SharkTuner page, and then click on the link on the LHS of the screen.

http://www.jdsporsche.com/faqs/LH22%...0Issue%204.pdf

John Speake

editted - I wrote the wrong # of aux inputs.....
<<<<<<<<<<<<<<

I thought I would draw atention to the Auxillary input that are provided when upgrading a SharkTuner with the LH2.2 option.

When tuning an 87-95 928, there are 4 aux inputs avalable for use with external sensors.

When tuning a 85/86 928 there are 3 aux inputs available (the 5th is reserved for the temp sesnor 2 indicator).

These inputs are rated at 5v maximum input.

They can be programmed to match the law of whatever sensor to wish to use, and the outputs are shown on the system monitor screen. The inputs are also available for datalogging and graphing.

The screenshot shows how useful these inputs cam be when debugging a s/c system. The boost plot looks reasonable enough, but the sensor placed in the path between the airfilter and the input to the s/c shows that there is a 3psi pressure drop at the top end. If that 3psi drop can be eliminated with a freer flowing intake, then up to 3psi boost will be available for "free"

The LH2.2 option also adds a fully programmable WBO2 input law, allowing easy use with WBO2 systems that can't at present be used with the SharkTuner e.g. Zeitronics

BrianG

John, I have been using the LMA-3 for peripheral data logging, and have been using the built-in vacuum-boost sensor.

For your system, or for a LMA-3 secondary pressure input, what sensor are you using??

John Speake

I don't know what type of sensors were used in the above plot. I can find out if it is important.

I think Louie used some GM ones. (but the above plot isn't one of his)

John Speake

Hi Brian
I have been given this info on the sensor...

"The MAP sensor used was MPX4250AP from Freescale Semiconductors. That sensor is often
used with MegaSquirt."

928SS

after noting the same issue about not getting consistant results on the autotune when I did it over several days, I think it's the tip of a larger issue - baseline conditions and their impact on tuning.

I'd guess at porsche, they set the maps at a std environmental point. ie, sea level, std barametric pressure and temp. if someone tunes their motor in the eye of a hurricane or top of a mountian, I'd guess they may have issues if they swap situations. when I wanted the most out of my race motors, I'd tune in identical conditions (or as close as possible) prior to an event to insure max performance.

since most folks don't have an environmentally controlled dyno room and some variation can be delt w/the MAF, does anyone think we might need to be aware of the ambient conditions to some extent when tuning, and try to adjust for them somewhat on the LH??? ie a 100F day vs 60F day, altitude, etc..

John Speake

Hello Rob
The LH system is pretty well enviroment compensated, temps 2, MAF correct for air density etc etc.

You may have to correct a warm up map on a somewhat tuned engine, but the normal running condtions should be well controlled whether at sea level up up in them thar hills.....

You may get different cell values on different Autotune sessions, but that is more likely to be due to the Autotune algorythm than anything else. However, these variations should not result in great variations of running conditions. Some manual adjustment of some cells may always be required after Autotuning.

John Speake

The only time you will get air desnity (i.e altitiude) mixture variations is at high loads is if you are running a standard MAF and are hitting the max load cells hard.

The means that MAF voltage as read by the LH ECU has maxed out. So effectively you are running on an rpm only basis. Because the MAf is the main way that air desnity is compensated for, at these high load values you loose that compensation.

The solution is to use a SuperMAF.

928SS

very cool....

all4woody

What should the fuel pressure be for 30lb injectors at 8lb of boost? When I unhook the BEGI I get 35psi and I don't think that is enough.
Thought? Questions?
Woody

John Speake

You shouldn't need a BEGI at all. Assuming your car is >MY87 you can retain a stock fuel system, where idle pressure is around 55psi IIRC.

DR uses a stock fuel system, and 30# injectors for his S4/GT/GTS kits - SharkTuned.

The GT version typically makes around 450rwhp.

Jim R.

I just had the pleasure of watching 2 experienced users put the sharktuner through its paces on my SC'd GT. Great tool, opens up many more possibilities to improve on our cars.

Nice work on the making the sharktuner John!

Jim

John Speake

I've just read your thread on your Stage 3 - excellent job !

Makes the development work of the SharkTuner worthwhile for Niklas and myself to get such great feedback :-)