DW400 Fuel Pressure Dropping During WOT - Whipple Stage 2

[Face]

Are you losing battery voltage thorough the pull at all?

No sir- its consistently above 13.8+ under WOT.

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[engineermike]

Is the lift pump hitting a max at 42% dc? Or is the scale not shown?

The tune has a fuel pump max dc and most make sure it’s 49-49.9.

 

[engineermike]

Btw, the initial dip is normal and you can see the pump dc ramping up as quick as it can to meet demand.

 

[brianbr]

No sir- its consistently above 13.8+ under WOT.

I wonder if your stock pump controller has an issue.

 

[Face]

Is the lift pump hitting a max at 42% dc? Or is the scale not shown?

The tune has a fuel pump max dc and most make sure it’s 49-49.9.

It is- Max DC is 42.6 during the pull. From what Lund told me "the target pressure is flat on the log but the pump isn't capable of hitting it."

 

[engineermike]

I find that very strange. The attached is my calibration data and lift pump log data from before the BAP. This is a DW400. You can see the lift pump DC max out at 49.9 just like the tune allows, then the fuel pressure drops to about 58 at 7500 rpm and 1.75 load. I checked a bone stock 2020 file and the Max DC is 49.0.

 

[TEXAS HEAT]

Sorry, I had to load a different config- but here it is.

I think Engineer Mike has indicated that 48psi is Max duty cycle, It is interesting that it flatlines up top, which to me seems to be max duty cycle. Is the Y-axis percentage in this plot? What rpm are you spinning the motor to? I also see your lift pump loses pressure on the hit as does mine. This may be normal though.

Edit: It appears as though others have already asked and answered the questions I was wondering about.

 

[Andy13186]

I have a whipple with a dw400 and vortech BAP on e85 I think mine may taper off some too but IDK if its actually a problem, car runs great. Heres a log, PBD is the tuner. I need some type of datalog reading configuration. Log is huge but its just a lot of normal driving with a few pulls toward the end, let me know what you think if you can read it. https://www.dropbox.com/s/bq5ssr8psuzvlqx/log0179.csv?dl=0

 

[TEXAS HEAT]

Btw, the initial dip is normal and you can see the pump dc ramping up as quick as it can to meet demand.

My stock pump also does this, but not as bad as OP's.

 

[engineermike]

My stock pump also does this, but not as bad as OP's.

This is why they had to dynamically control injector pulsewidth as a function of fuel pressure. Lift pump feedback control wouldn’t be possible otherwise because of these momentary dips and spikes.

 

[TEXAS HEAT]

This is why they had to dynamically control injector pulsewidth as a function of fuel pressure. Lift pump feedback control wouldn’t be possible otherwise because of these momentary dips and spikes.

That actually makes sense Mike, thanks! You're a wealth of knowledge here.

 

[illtal]

bap should fix it, if not it's probably an electrical issue with the voltage. Shouldn't be though: my 18V boosted stock pump never goes above 32% DC

 

[engineermike]

I’m running an 18v boost a pump on the dw400. This morning i logged 45% max dc (90% actual) running 13 psi boost.

I’m mostly perplexed by the TEXAS HEAT’s 42% max dc with falling pressure. It should absolutely hit 49% if pressure is below setpoint. It’s almost as if they fat fingered the max dc in the tune.

 

[TEXAS HEAT]

I’m running an 18v boost a pump on the dw400. This morning i logged 45% max dc (90% actual) running 13 psi boost.

I’m mostly perplexed by the TEXAS HEAT’s 42% max dc with falling pressure. It should absolutely hit 49% if pressure is below setpoint. It’s almost as if they fat fingered the max dc in the tune.

Hey Mike, I'm not anywhere near that in most of my logs. The most duty cycle I have seen is about 37%, but the lift pump pressure does drop and duty cycle does go up at the same time.

 

[Face]

For what its worth my BAP is going in today and hopefully I should be back on the dyno tomorrow- will report back with results.

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