FG F6 - The Tuning Journey

[demon1300]

Hi Guys,

My first post on the forums here, been reading as much as i can after recently buying an MPVI pro I still have lots of questions though, so figured i'd start a thread to start improving my understanding and get a better end result!

So the car was originally tuned by a well known workshop in Melbourne (whilst i owned it). I've always had interest in tuning myself, so figured why not delve into it myself so that i can dial it in better over time. It had also developed a bad miss at idle after changing the fuel pump and putting some valve springs in, so figured it was perfect timing to start trying to get it right on my own. The more i look at what the major workshops do, the more i'm glad I've started tuning my own car I guess no one cares for or will spend the time on my car like me

So the first question is around the slope data that i'm currently using. The car has genuine ID1000's and i've recently gauged the base fuel pressure at 67psi at idle with a KPM twin pump in tank system and reg to suit (that comes in the kit). Now i realise that the base pressure is higher than the stock 4 bar, so figured that the injector slope info that was in the car before would be wrong, as it had a stock pump setup.

I also learned pretty quickly, that since changing the pump setup it was adding up to 15% on the long term trims and up to 15-20% on the short terms. Waaaaaaay off...

Now I've measured the base pressure, i've plugged that info into the ID data sheet and come up with the numbers required. On the first re-flash, it was waaaay to lean using the data from the sheet. The low slope was up around the 130 lb/hr which was obviously compensating for the higher than standard fuel pressure.

I've managed to bring the slope numbers down now for the low to 121.500 which has seen in the logging the LTFT's come down to basically 0, the most i've seen is +1.8%. So much better on the commanded lambda front. The High slopes I've also richened up, by bringing down to 105 ish lb/hr to bring it closer to the commanded under heavier loads.

So back to my original question - regarding the voltage offsets. I'm still using the voltage offsets calculated by the ID spreadsheets based on the higher slope numbers. Should I now be reverse calculating to the offsets based on the lower slope numbers as now that's what it's running to keep the commanded lambda in check?

This is what i'm currently running for the voltage offsets:

Capture.JPG

What do they look like to you guys? I had to fudge or guess the highest voltage numbers as the ID data doesn't go up that high. I don't think the charging system would get that high either. I could always interpolate that value I guess...

There will be much more questions to follow

Cheers,

Rob

[turbotrana]

What is the pressure with the vacuum hose disconnected from the FPR. That is what you are meant to measure for starters. It should be 4 bar. Then use the data that is on the ID1000 thread as the starting point.
Your fuel pressure regulator needs to have the ability to go low, what ever it can go down to in full deceleration. If not you need to get a FPR that can. I know its a twin pump and hard to get it there, but in my fuel systems it needs to operate like that before I start tuning.

[demon1300]

So the fuel base pressure is 67psi at idle with the vac line off and blocked. It's as low as its going to get with this stock fuel rail and pressure reg. I could obviously get it down by running a custom rail and reg. Shouldn't this be fine though and able to be scaled correctly as its well within the ID's working pressure range (sub 100psi). I figured that as long as they're scaled correctly for the new pressure, the rest of the fueling should be ok as that's the only thing that's changed. Am i missing something here?

[Molch]

welcome onboard demon1300, I'm still fairly new to tuning with hptuners like you but will keep an eye out on this thread and if I can help I will. I can't help much with the fuel pressure issues your having but my next purchase is possibly also the KPM 1000hp pump so keen on the outcome.

[turbotrana]

As I said, you need to have a proper operating fuel system before you can tune properly. The fuel pressure gauge on your modified setup needs to mimic what happens with a stock setup under all conditions. Ie under load but also under deceleration. So when you put the vacuum line on, does it pull the pressure down. If so, down to what pressure. Get someone to rev the engine and see where the pressure goes on a hard jab of the accelerator. Interested in what pressure it goes down to on the deceleration of the engine.

[demon1300]

So the fuel setup that's on the car is a complete KPM 1000hp twin pump in tank (dw300's) with their custom resized reg. Still running the standard fuel rail. A mate of mine has a dyno and fuel pressure gauge, so figured we'd test it to be safe. Base pressure was 67 psi at idle, although with the vac line on it came down to around 61. It was seeing 80 psi at WOT, whilst I was filming the gauge on the dyno runs. To me, that's not too bad?

I believe KPM have engineered this kit to retain all the factory pressures etc so you don't run into the crazy fuel pressure issues that putting aftermarket pumps have with standard regs?

I'm honestly thinking I'll buy a fuel rail and fpr1200 for it anyway, just so that it's adjustable in the future. Maybe I'll just got the fpr2000 as it's only like $20 more...

Any recommendations on rail? Plazmaman or Process West?

[45T-XR]

You could try enlarging the return port in the fuel pressure reg IN SMALL STEPS, and see if it drops the fuel pressure to 4 bar, but ideally, that is a band aid fix and you should be running an adjustable fpr anyway as you mentioned. I currently have a turbosmart frp1200. And I would recommend that you use a 2000 instead, it has a larger return port. From memory I'm down to -8 on the return. Yes you could run an adapter to step up, but it doesn't change the physical size of the restriction of the threaded port in the 1200

[IH8TOADS]

I would ring KPM and state that the fuel system is not operating as designed. Don't modify anything until they resolve the issue.

[IH8TOADS]

Also regarding the offsets, change the voltages themselves to match what ID do. No point having 3 or 4 rows for 6 volts when you can use the rows for more resolution around operating voltage.

[demon1300]

You could try enlarging the return port in the fuel pressure reg IN SMALL STEPS, and see if it drops the fuel pressure to 4 bar, but ideally, that is a band aid fix and you should be running an adjustable fpr anyway as you mentioned. I currently have a turbosmart frp1200. And I would recommend that you use a 2000 instead, it has a larger return port. From memory I'm down to -8 on the return. Yes you could run an adapter to step up, but it doesn't change the physical size of the restriction of the threaded port in the 1200

Yeah OK. Why are you running out of return with -8? That's a damn lot of fuel return. I'm still not sure which one to go with, considering that i'm going to retain the stock hard line for the supply and return from the tank. That and the in-tank pump setup is only rated to 1000hp (ample) so maybe the FPR 1200 is better and might look a bit tidier considering it's all -6 lines (easier to tuck away).

I would ring KPM and state that the fuel system is not operating as designed. Don't modify anything until they resolve the issue.

Yeah i could, but i brought the kit new off a guy who never used it. Still have the receipt, but i think i'll be chasing my tail trying to get KPM to fix it as in their installation manual it states that the base fuel pressure at idle after install should be between 450kpa (65psi) and 500kpa (72psi) - which it is. I think i'll be just going the aftermarket route as i know that i can adjust it and check it regularly.

Also regarding the offsets, change the voltages themselves to match what ID do. No point having 3 or 4 rows for 6 volts when you can use the rows for more resolution around operating voltage.

I didn't realise that i could adjust the scalars! I'll go and check that now

[45T-XR]

I will have to double check, I might have -6 return. It's been so long since I installed it. I just had in my memory that whatever size I wanted to go with I was limited by the physical size of the return port in the Reg of the 1200.
I haven't used one of those KPM setups, are the designed to be run with the stock FPR?

[Molch]

I believe the kits come with a new 4bar FPR. The below is from another forum:
Streetfighter 1000Hp Twin Intank Pump Module Sedan

Price Includes:
Streetfighter 1000hp Fuel Pump Module complete.
Full patch loom and relay kit for direct plug into factory loom
New 4 bar High Flow Fuel pressure regulator
GST included

[45T-XR]

I double checked the 1200, it only has -6 return.
They run a patch loom for the twin pump....I wouldn't have thought the stock wiring would be up to the task for 2x pumps simultaneously? I'll check the current draw on those DW300s

[IH8TOADS]

That's their base pressure (65+ psi) but they don't actually have calibration data above 4 bar base for their own injectors. Wow.....that's quite special!!

[demon1300]

I believe the kits come with a new 4bar FPR. The below is from another forum:
Streetfighter 1000Hp Twin Intank Pump Module Sedan

Price Includes:
Streetfighter 1000hp Fuel Pump Module complete.
Full patch loom and relay kit for direct plug into factory loom
New 4 bar High Flow Fuel pressure regulator
GST included

Yeah, that's the kit i have as well as their billet 1500hp fuel filter.

I double checked the 1200, it only has -6 return.
They run a patch loom for the twin pump....I wouldn't have thought the stock wiring would be up to the task for 2x pumps simultaneously? I'll check the current draw on those DW300s

Yeah it comes with a patch loom and some decent gauge wire that runs to a relay in the bay. All in all it installed pretty easily. It's def too much current draw with the stock loom, i think at the pressure they're running at now, they're up around the 10-12 amps each.

That's their base pressure (65+ psi) but they don't actually have calibration data above 4 bar base for their own injectors. Wow.....that's quite special!!

lol, seems pretty ludicrous. I think i'll order an frp1200 and gauge in the next few days, just need to decide on which fuel rail to get. I do like the look of this process west one and the way the reg mounts at the back, only you'd have to turn it around so that you could see the damn gauge!:

largefuelrail3.jpg

P.S - Also what's wrong with the damn image insertion part of the forum, i keep having to upload them as attachments!

[IH8TOADS]

Drop the return line into a bucket and see if the pressure drops before you go out and buy a regulator.

The pressure shouldn't even have a range. What a joke. Get some answers from KPM.

[demon1300]

I'm happy to just buy a reg and rail and be done with it if i can't get the same results using a higher pressure that i'm running (which is what i thought i could achieve through re-scaling).

It would also be handy to be able to check the pressure again in the future with just the pop of the bonnet (because these god damn computers are so limited vs the GM variants!)

[andyt12]

hi demon1300,

Whats the bosch part number for the KPM supplied regulator?

Cheers

[turbotrana]

I am not a fan of operating fuel pressure regulators above 90psi (base + boost). I have turned up a couple of brands to 100psi+ and they are simply are out their sweet spot operating range. Neither do injectors like to be there.

So if you had your base FP of 67psi and add 20 lb of boost, you are in an area where both the FPR and Injectors do not operate in the best range.

Thats why I think its best you start at 4 bar (58psi) for a 20psi boost and lower the base fuel pressure should you start upping boost to 30+psi. I normally operate base FP at 3 bar.

[demon1300]

hi demon1300,

Whats the bosch part number for the KPM supplied regulator?

Cheers

Hi Andy, not sure to be honest without pulling it out and checking it. I'll be able to get it for you shortly as i've just pulled the trigger on an FPR2000 and will install it over the next few weeks.

I am not a fan of operating fuel pressure regulators above 90psi (base + boost). I have turned up a couple of brands to 100psi+ and they are simply are out their sweet spot operating range. Neither do injectors like to be there.

So if you had your base FP of 67psi and add 20 lb of boost, you are in an area where both the FPR and Injectors do not operate in the best range.

Thats why I think its best you start at 4 bar (58psi) for a 20psi boost and lower the base fuel pressure should you start upping boost to 30+psi. I normally operate base FP at 3 bar.

Yeah. FPR2000 has been ordered and will install it shortly. I'll bring it back down to a propper FG base of 4bar, then re-scale the injectors and start again. Fun times!