Required Upgrades for E-85?

[cbrtrx]

I have lift pump pressure drop not rail pressure drop. Ess 120mm 93

How are you measuring your low pressure fuel pump drop? The sensor is on the rail.

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[Pistol_91]

How are you measuring your low pressure fuel pump drop? The sensor is on the rail.

Actual/desired lift pump pressure PID

 

[cbrtrx]

Actual/desired lift pump pressure PID

That drop you're seeing is mostly from the fuel rails. What is it dropping to after 7k? Are you running a factory pump with a bap?

 

[Pistol_91]

That drop you're seeing is mostly from the fuel rails. What is it dropping to after 7k? Are you running a factory pump with a bap?

Yes I am. It has been months since I've ran e85.. Off the top of my head I believe it was getting down to 35ish psi when pushing it the hardest. I think on average it would maybe drop to 45ish psi give or take. Rail pressure and PW still good. With 93 it doesn't budge. You're thinking the rails are the limiting factor here?

 

[cbrtrx]

Yes I am. It has been months since I've ran e85.. Off the top of my head I believe it was getting down to 35ish psi when pushing it the hardest. I think on average it would maybe drop to 45ish psi give or take. Rail pressure and PW still good. With 93 it doesn't budge. You're thinking the rails are the limiting factor here?

It's the rails, I figured this out years ago. I was skeptical at first because I've pushed stock gen 2 rails to 900 wheel but gen 3 rails have a massive pinch point. I changed my rails and gained significant overhead.

The gen 3 logic also compensates for pressure drop, even at 40 psi you should still achieve commanded wot lambda unless your injectors are very small. Anything less then that I don't risk it especially on cooler nights.

 

[engineermike]

If I were to convert my TI 274s into a single pump setup that I can drop into my radium bucket, is there a pump that’s more than up to the task of 1000rwhp and also a turn key solution? Essentially, remove 274s, drop in pump XYZ and send it.

When you boil it down to "single pump, high capacity, venturi connection, check valve" the list gets very, very short. I can't find a brushed pump that outperforms the DW400 and meets that criteria. On the brushless side, the best fit I've found is the fuellab pump but its rated capacity at 13.5 volts is less than a DW400 will do at 18 volts. And with brushless, it may not benefit from higher input voltage. If it did, you'd wind up having to run a BAP, FPDM, and brushless controller all in series.

 

[cbrtrx]

Yes I've found a dw400 with a bap on a gen 3 with fuel rails to be surprisingly effective on e85. Now I mean if you're trying to push over 800 rwhp then yes you'll have some pressure drop, and in cooler temps it could start to get risky. I'm hoping in the next few years there will be even more options but I think many companies don't see the demand because the brushed multi pump setups are still selling well.

 

[engineermike]

I was always under the impression that the PWM managed pulse width and duration so constant voltage, just varying intermittent current. So instead of a DC current, you get almost a multi-phase current based off how wide the pulses are. I suppose it could also vary the height (voltage of the pulse). In order to vary voltage, it would need much larger infrastructure (with heat sink/fins for venting) no?

PWM is a constant frequency square wave alternating between supply voltage and 0. The pulsewidth/period is the duty cycle. The frequency is high enough that the average of the voltage over time is the voltage that is applied to the load. So a 75% duty cycle with a 12v input results in an apparent 8 volts.

If you look at a variable output BAP, it first has to use an inverter to create AC voltage in order to use an inductor to step up the voltage, since DC can't be stepped up directly. Then a rectifier is used to convert this higher AC voltage back to DC. Then a PWM circuit is used in the variable output models to turn the voltage back down when the need isn't there, and the stock FPDM steps voltage down again unless the PCM logic decides it needs to be full-tilt. If you didn't want a PWM I suppose you could have several inductors with intermediate voltage steps, but the PWM works so well there really isn't a reason to do it this way.

 

[Angrey]

When you boil it down to "single pump, high capacity, venturi connection, check valve" the list gets very, very short. I can't find a brushed pump that outperforms the DW400 and meets that criteria. On the brushless side, the best fit I've found is the fuellab pump but its rated capacity at 13.5 volts is less than a DW400 will do at 18 volts. And with brushless, it may not benefit from higher input voltage. If it did, you'd wind up having to run a BAP, FPDM, and brushless controller all in series.

The DW440 is rated intermittent to 22V and constant at 18V. With one pump you could probably run well over 1k rwhp blown, E85 with a siphon loss.

At 70 psi, the 440 flows 375 l/hour on 13.5V. So that would be roughly 500 liter/hour at 18V and 611 liter/hour at 22V intermittent max condition. The controller is rated to 26V and 40 amps. Even with system friction losses and a siphon, that should get to 4 digits (18 lbs of boost, 68 psi fuel pressure, 8k rpm redline with 5.0, V8, 4V/Cyl on E85 with a moderately aggressive cam).

The ID fuel calculator is one of the better ones and suggests that takes about 544 liter/hour to the rails, so that leaves the rest for siphon losses and pressure drops.

https://cdn.shopify.com/s/files/1/0414/1681/8852/files/DW440_Brushless_Tech_Sheet.pdf?v=1702576078
https://cdn.shopify.com/s/files/1/0...-ae91-40f3-b6d1-50f495de415e.pdf?v=1702575090

Admittedly, the 440 is over twice the cost of the DW400, but should last MUCH MUCH longer and be able to be pushed harder with virtually no reduction in reliability.

 

[Pistol_91]

It's the rails, I figured this out years ago. I was skeptical at first because I've pushed stock gen 2 rails to 900 wheel but gen 3 rails have a massive pinch point. I changed my rails and gained significant overhead.

The gen 3 logic also compensates for pressure drop, even at 40 psi you should still achieve commanded wot lambda unless your injectors are very small. Anything less then that I don't risk it especially on cooler nights.

I will try that out then. Simple enough.
And yes you're correct lambda still at commanded, never creeps towards lean. I have ID1000s. I'll look into some rails and report back.

 

[cbrtrx]

I will try that out then. Simple enough.
And yes you're correct lambda still at commanded, never creeps towards lean. I have ID1000s. I'll look into some rails and report back.

If you do rails don't deadhead each rail use a crossover as well otherwise you'll see some bank to bank fueling issues because one side has the high pressure nipple on it. With the crossover it will equalize the rails.

 

[engineermike]

Yes I've found a dw400 with a bap on a gen 3 with fuel rails to be surprisingly effective on e85. Now I mean if you're trying to push over 800 rwhp then yes you'll have some pressure drop, and in cooler temps it could start to get risky. I'm hoping in the next few years there will be even more options but I think many companies don't see the demand because the brushed multi pump setups are still selling well.

I agree with all of this.

The other thing is that the gen3 attempts to run 72 psi at wot, while the gen2 setpoint is 58. If we allowed the DW400 at 22 volts to run at 58 it would have more capacity. I can't do that on my 55# injectors but with some bigger ones I could push the DW400 even farther.

 

[Pistol_91]

If you do rails don't deadhead each rail use a crossover as well otherwise you'll see some bank to bank fueling issues because one side has the high pressure nipple on it. With the crossover it will equalize the rails.

My thoughts exactly too. Any recommendations

 

[cbrtrx]

My thoughts exactly too. Any recommendations

I did Radium, Y off of the feed line then to the back of both rails then a front crossover just to equalize pressure. Worked out great. I was using a dw400 with a bap at the time. I since have upgraded to the radium bucket with twin pumps. Still have a single feed deadhead system like that and it works very well.

 

[LOL WUT]

@engineermike @Angrey

Thanks for the insights on the pumps!

I don’t really PLAN to go a lot further with my car HP wise (currently high 700s at the wheel) but I always want my fuel system overbuilt by a lot. Knowing that my 274s likely won’t last forever, I am trying to be proactive in my planning for new pumps. It sounds like a pair of dw 400s or 440s would be way overkill (if they’d even fit) but give me ample peace of mind.

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