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Author Topic: c_mfp_max for autotech (or other) hpfp  (Read 5042 times)
k0mpresd
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« on: June 18, 2019, 08:58:24 PM »

anyone care to share what they are using or the calculation behind the value they decided was correct?

i have seen “autotech hpfp” files even with stock mfp_max. have also been told 400-450mg/stk works best. the latter seems a bit absurd as that is almost double the factory value.

i have tested a lot of varying values all the way from 266 > 386mg/stk and none seem to really make the controller happy.

from how i understand, the vcv control is a matter of mfp_req/mfp_max and then all other calculations seem to be derived from this, open/closing angle of vcv for pump efficiency and high pressure control.

maybe my understanding is lacking a bit.
or maybe i just should change back to the factory pump to make my life easier.
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littco
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« Reply #1 on: June 19, 2019, 03:47:32 AM »

I've always run 232mg which is stock and never had an issue.

What sort of power levels and hpfp pressure are you running

Also what sort of issues are you seeing?
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k0mpresd
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« Reply #2 on: June 19, 2019, 05:12:26 AM »

I've always run 232mg which is stock and never had an issue.

What sort of power levels and hpfp pressure are you running

Also what sort of issues are you seeing?

at this point i sort of feel like the autotech is just a giant waste.
if the stock mfp_max “works” and does not cause pressure variations or pump volume control deviation swings by a large margin in either direction then stock and autotech = same.

the mfp_max is used as a constant for all the other calculations for fuel mass control.
(again only as i understand how it works so far).

220bar req however actual has variations +/- 3-4 bar in places. also depending on the mfp_max value, the control deviation can be quite a large negative or positive number.

it just seems to be working quite too hard to be acceptable.

the only running condition issue i notice is a “hiccup” after a gear change from high rpm.
example:

gear 2 > gear 3 change at ~6900 rpm. rotations drop to ~4900/5000.
the injection ms will go super high (10/11ms) range, then the inj ms will go super low (4/5ms) and this giant oscillation will cause a stumble. the inj ms in this rpm should be about 7.5-8ms for proper running condition.

i have rescaled the fuel mass maps for injection time vs pressure/mg/stk.

i can not decide if i think this hiccup is related to the pump control or maybe the pressure axis needs to be scaled higher to handle pressure spikes better or if there is something else in the calibration that should be addressed.

the car runs ~78% ethanol with an upgraded lpfp.  
« Last Edit: June 19, 2019, 05:14:16 AM by k0mpresd » Logged
littco
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« Reply #3 on: June 19, 2019, 05:48:52 AM »

So we've been running to 470bhp and 420ftlbs more recently on the stock pumps with out issue. The hpfp is only needed if want more torque in the mid range .

I think I'm going to ditch upgraded hpfp anyway and just use larger mpi for the extra fuelling as the injectors are actually cheaper and you can get more fuel with them anyway. Seems a pointless exercise to run a upgrade hpfp and larger mpi with ethanol as both arent required
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k0mpresd
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« Reply #4 on: June 19, 2019, 06:39:09 AM »

So we've been running to 470bhp and 420ftlbs more recently on the stock pumps with out issue. The hpfp is only needed if want more torque in the mid range .

I think I'm going to ditch upgraded hpfp anyway and just use larger mpi for the extra fuelling as the injectors are actually cheaper and you can get more fuel with them anyway. Seems a pointless exercise to run a upgrade hpfp and larger mpi with ethanol as both arent required

i think i will go back to the stock pump as well, just to remove as many variables as possible. really not seeing where this autotech does anything truly beneficial besides just making it seem more exciting that the hpfp is "upgraded".
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littco
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« Reply #5 on: June 19, 2019, 10:51:21 AM »

i think i will go back to the stock pump as well, just to remove as many variables as possible. really not seeing where this autotech does anything truly beneficial besides just making it seem more exciting that the hpfp is "upgraded".

The autotech is the smallest of the pumps, the Loba next and the VIS the largest. I can't recommend the VIS at the moment as the quality has been pretty bad recently and we had to stop using them after a couple of issues.

Stock pump is imho good to about 440ftlbs by which point the HPFP starts to struggle to keep up at around 215bar. Once engine is past the peak torque the HPFP isn't needed as you can run the stock one upto similar MG/STK at the redline. On some cars we've run 470-490ftlbs and there is no way the stock HPfP will keep up, as we've seen pressures drop to 170bar even with a level 6bar LP but it really is this hump they need to get over as once the HPFP has the RPM and the LP can be maintained then the Stock on is fine to the redline.

The price of the Autotech V the larger injectors which is needed for Ethanol anyway probably makes it a better option anyway.
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k0mpresd
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« Reply #6 on: June 19, 2019, 11:20:20 AM »

The autotech is the smallest of the pumps, the Loba next and the VIS the largest. I can't recommend the VIS at the moment as the quality has been pretty bad recently and we had to stop using them after a couple of issues.

Stock pump is imho good to about 440ftlbs by which point the HPFP starts to struggle to keep up at around 215bar. Once engine is past the peak torque the HPFP isn't needed as you can run the stock one upto similar MG/STK at the redline. On some cars we've run 470-490ftlbs and there is no way the stock HPfP will keep up, as we've seen pressures drop to 170bar even with a level 6bar LP but it really is this hump they need to get over as once the HPFP has the RPM and the LP can be maintained then the Stock on is fine to the redline.

The price of the Autotech V the larger injectors which is needed for Ethanol anyway probably makes it a better option anyway.

i need to get the mpi installed if only for the simple fact of being able to log the LP. i bought all oem parts for the install except the injectors.
my current solution was to copy the duty % and pressure setpoint maps from the original calibration of the lpfp that i have installed.

though worth mentioning, i have been working with this autotech both before and after the lpfp install.

do you have any hpfp logs with the autotech and stock mfp_max value? i will not be able to work hands on with the car again until mid-july so i would like to develop a game plan before then.
decide if i want to remove and trade for stock or continue to torture myself with the autotech.

will also be upgrading from is38 > a larger turbocharger around the same time.
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Blazius
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« Reply #7 on: June 19, 2019, 12:21:42 PM »

What is this about Cheesy What car/s are we talking about.
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littco
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« Reply #8 on: June 19, 2019, 01:08:25 PM »

What is this about Cheesy What car/s are we talking about.

If you know you know.

Mqb
« Last Edit: June 20, 2019, 12:29:03 PM by littco » Logged
prj
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« Reply #9 on: June 20, 2019, 12:49:32 AM »

I managed to do 500 PS on stock fueling.
I didn't have a problem in the midrange - there you can't run enough boost anyway unless you drop compression or have some fancy fuel.
But I had a problem at 5000 rpm and after. There I had to use the small MPI injectors to compensate.

And then it was just enough to feed the LM500 turbo.
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k0mpresd
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« Reply #10 on: June 20, 2019, 02:44:52 AM »

I managed to do 500 PS on stock fueling.
I didn't have a problem in the midrange - there you can't run enough boost anyway unless you drop compression or have some fancy fuel.
But I had a problem at 5000 rpm and after. There I had to use the small MPI injectors to compensate.

And then it was just enough to feed the LM500 turbo.

happy with the LM series?

i actually purchased the LM440 variant and it should be arriving just about the time i return from holiday. Smiley
« Last Edit: June 20, 2019, 02:51:27 AM by k0mpresd » Logged
littco
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« Reply #11 on: June 20, 2019, 05:46:54 AM »

I managed to do 500 PS on stock fueling.
I didn't have a problem in the midrange - there you can't run enough boost anyway unless you drop compression or have some fancy fuel.
But I had a problem at 5000 rpm and after. There I had to use the small MPI injectors to compensate.

And then it was just enough to feed the LM500 turbo.

We nearly always max out st 490bhp/440ftlbs on stock fuelling which lines up with you.

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prj
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« Reply #12 on: June 20, 2019, 08:41:19 AM »

The LM500 spooled well and did not give me any trouble. It's also still together after a year of use.
But I only have tuned one car with a such turbo, so it's a small sample size.
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