WOT from low RPM vs high RPM

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stevieturbo
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Re: WOT from low RPM vs high RPM

Post by stevieturbo »

I doubt it. Seems more a pump/filter/wiring, ie. fuel flow problem problem.

And get that safety on relfp added !
secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

Re: WOT from low RPM vs high RPM

Post by secure »

I have had both visual or audible warnings in Realdash/Syvecs but fuel sloshing on the track made it annoying so closed that warnings.

Fuel pump is Walbro 460 hardwired(12awg) with custom fuel filter.

It could be aeromotive diaphram because its been almost ten years and lately the engine sometimes doesn't want to start

Anyway I'll check from tank to inj . Thank you for your inspect!
stevieturbo
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Re: WOT from low RPM vs high RPM

Post by stevieturbo »

Clearly at lower loads, the system is capable of making pressure....otherwise it wouldn't be dropping under boost.

You could bench test at no load by applying pressure to the FPR, although as there is no loss in the system ( ie the engine ) it's a little bit of a false test, but it would at least verify the system is capable at some point of generating the pressures you need

But relFP should be a static value give or take a little, if it is deviating a lot, then warnings based around it are not to be ignored, and dropping so much ( relative ) fuel pressure at so little boost....is a huge concern.
secure
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Re: WOT from low RPM vs high RPM

Post by secure »

Image

Here is the fix. Changed the blue hose and the fuel pressure drop at 1.0bar @boost is 3 psi now.

It went too rich. I need to restore my fueling table back. Actually I should have never touch the fueling table before diagnosing.
anyway always trust your gut feelings and investigate :mrgreen:
stevieturbo
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Re: WOT from low RPM vs high RPM

Post by stevieturbo »

Or if you had relFP compensations....fueling may have stayed close to "correct" anyway, despite the problem.

Use that, and the relFP safety trip.
RICE RACING
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Re: WOT from low RPM vs high RPM

Post by RICE RACING »

stevieturbo wrote: Fri Dec 04, 2020 6:14 pm Or if you had relFP compensations....fueling may have stayed close to "correct" anyway, despite the problem.

Use that, and the relFP safety trip.
Take Stevie's advise as gospel, lots of people and tuna's just don't get the basics right.
Here is example of what he is saying in action, keep in mind this is ultra critical for when in example you fuel correction limits are exceeded then it wont work OR you are on action of limiters on TC to pick one, again it wont work and its down to the brains who set up your ECU, be that you or someone who thinks they know or charge like they know what they are doing :roll:

This is a 700bhp rotary 13B turbo (most shit engine on earth for toughness, will detonate at first chance you give it!) where the fuel system had a problem but due to a great design and set up there is margin everywhere to account for even extreme situations like this, you can see it all happens VERY FAST, and it takes experience to set up right, but here the CLL turns off as its past its margin of error, the multiplier for loss of fuel pressure keeps it all happy (assuming you sized fuel injectors correctly!) and once the final trip condition is met it finally says 'fuck you moron fix this shit set up' and forces a limp.

Hope this helps.
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secure
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Re: WOT from low RPM vs high RPM

Post by secure »

https://youtu.be/bs9IJrXZYLk?t=133


Watchout oil pressure > 2:13 and oil trip in action.
I've experienced this in the past. Normally all my trips were on. But on the track its almost impossible to go without having fuel slosh or oil starvation for my car(setup). Injector duty is %99 so really nothing to compensate here. I have yaw rate sensor but using its LATG output for fuel slosh&dccd. When it comes to braking from 220 kph having oil starvation and I need longitundinal input not to trigger the trip.

I think what really compansate here is the base fuel pressure of the regulator set high(5 bar). I still think #3 cylinder may be suffered lean condition. If I would be on the track boosting 1.5bar with E70 probably the engine could fail.(but I still have knock trip too)
I need to fix oil and fuel sloshing.
Healty car = healty setup first.
RICE RACING
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Re: WOT from low RPM vs high RPM

Post by RICE RACING »

You can use my probes to check cylinders, they are inexpensive and proven durable for such a demanding task > http://www.riceracing.com.au/Syvecs_Index.htm we use them in every turbo car as unlike fitting a lambda sensor these don't fail and have many advantages which a lambda sensor wont see like runaway knock to name the most important one.
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RICE RACING
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Re: WOT from low RPM vs high RPM

Post by RICE RACING »

Some one else can chime in but for me a trip, limp, limiter etc (dose not matter what it is) simply is there to do what it says.
If you have oil surge, lack of injector, fuel pick up problems then you need to fix those, the ECU is not Jesus, it cant perform a miracle last time I looked. Sure it will stop your motor from going to hell, but it will always be on the Devils door trying to get in if the set up is shit.
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stevieturbo
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Re: WOT from low RPM vs high RPM

Post by stevieturbo »

secure wrote: Sat Dec 05, 2020 8:14 pm
I need to fix oil and fuel sloshing.
Indeed you do. Although even the video shows no data relating to fuel or oil pressure.

And you are maybe misunderstanding the importance of that relFP fuel multiplier. It IS the fastest response to a falling fuel pressure to try and retain some normality to fueling without re-tuning etc. With perhaps the only caveat that might mask a problem.....except it won't if you're keeping a check on FP or relFP.
#relFP matters

In your case though, you say injectors are at 99% ( no wonder with fuel pressure falling so much ), closed loop was off...another risk without safeties in place.
And fuel pressure falling massively...which relFP and FP trips should have caught and prevented.

Really....with so many issues taking the car around a track is a bit mad. And with safeties in place from the outset, issues like that FPR hose would have been caught earlier.

A small deviation in relFP as long as it is consistent and repeatable is not a concern. But again, you'll establish what is your normal, and set the trips accordingly.

If EOP dips are an issue that might lead to a trip action and of course they need fixed, you could simply put a time delay on any trip actions, although of course ideally you'd sort the oil system, although that's not always a cheap or easy fix. But nor are engine rebuilds.

The Syvecs safeties are great features....make use of them where possible, even if they are slowed down to accommodate a poor setup. A slow response is better than no response.
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