Rising rate FPR

[AngryRB]

My RB3025 making 345kw had E85 fuel issues with dirty injectors so I cleaned them and changed the reg to a rising rate one. 

The tune was done with a stock reg so I'd like to ask will the rising rate reg mean the tune be off? Like will it now be much richer on boost and need just a tidy up or a full retune?

 

Edited April 4, 2020 by AngryRB

[Dose Pipe Sutututu]

Maybe, if your old reg wasn't raising the fuel pressure 1:1 with your manifold pressure then you'll need a retune.

If it was working correctly then no, you'll probably notice better transient throttle too with a proper fuel reg.

[KiwiRS4T]

  On 04/04/2020 at 6:45 AM, AngryRB said:

My RB3025 making 345kw had E85 fuel issues with dirty injectors so I cleaned them and changed the reg to a rising rate one. 

The tune was done with a stock reg so I'd like to ask will the rising rate reg mean the tune be off? Like will it now be much richer on boost and need just a tidy up or a full retune?

 

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Why did you change the FPR? If you didn't replace the old one with a stock one or a 1:1 unit but one with a rising rate such as 1:2 then you will need to touch up the tune.

[Murray_Calavera]

Are you a million % sure it is a 'rising rate' FPR? 

I'm guessing you have a vacuum/boost referenced FPR that increases the fuel pressure to match the increase inlet pressures. It scales at 1:1, so 1 psi increase in boost, 1 psi increase in fuel pressure. This is how the stock one works, and I'm guessing that is also how your one works. 

Back in the 90's people used to add rising rate FPR when tuning was very primitive as a way of turboing their NA cars. I haven't heard of anyone using a rising rate reg for at least 15 years now, could be more. 

Can you add a weblink to the FPR you installed?

[AngryRB]

It's a black Aeromotive FPR from efisolutions  , I replaced it cause the old tuner said the fuel system was all clogged up from E85.  The old reg is over 20yr old so thought is a good improvement, I set the pressure to 44psi but tuner says its raising the pressure with boost alot different to a stock reg so the fuel map needs retuned.

Before we could tune it, a Welsh plug backed out from the back of the head right next to the fire wall.  So just wondering if it really needs a tune still cause i cant smell much fuel if its apparently rich and no knock showing on power fc either.

 

 

Edited April 4, 2020 by AngryRB

[KiwiRS4T]

"Black" is not specific enough - they make a range of units (including a basic 1:1 unit). What is the part number? It shouldn't knock if it is running too rich. Don't suppose you have a wideband afr meter installed? How does the tuner know what it is doing? Did he put a meter in your exhaust or a fuel pressure meter in the fuel line?

[r32-25t]

Most fuel pressure regulators are 1:1 rising rate even oem ones 

[AngryRB]

  On 04/04/2020 at 10:51 AM, KiwiRS4T said:

"Black" is not specific enough - they make a range of units (including a basic 1:1 unit). What is the part number? It shouldn't knock if it is running too rich. Don't suppose you have a wideband afr meter installed? How does the tuner know what it is doing? Did he put a meter in your exhaust or a fuel pressure meter in the fuel line?

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Aeromotive 13129, rated 1200hp..

No wideband, tuner plumbed his own guage in the line and showed me the pressure changing, I'm not sure exactly what i was looking at now.

I guess I'll just put her back on dyno then.

[Murray_Calavera]

  On 04/04/2020 at 11:21 AM, AngryRB said:

Aeromotive 13129, rated 1200hp..

No wideband, tuner plumbed his own guage in the line and showed me the pressure changing, I'm not sure exactly what i was looking at now.

I guess I'll just put her back on dyno then.

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Winner winner chicken dinner. https://www.summitracing.com/parts/aei-13129

It's 1:1. Same as the factory FPR. 

This is not a 'rising rate' FPR. 

[AngryRB]

That's weird then, last time it was tuned it was maxing out the 400lph walbro with 1000cc injectors on E85,  is that about right or was the stock reg leaking maybe...

Edited April 5, 2020 by AngryRB

[KiwiRS4T]

  On 05/04/2020 at 12:27 AM, AngryRB said:

That's weird then, last time it was tuned it was maxing out the 400lph walbro with 1000cc injectors on E85,  is that about right or was the stock reg leaking maybe...

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What do you mean "maxing out the Walbro"?  Did the tuner say you were running out of fuel supply? What was the duty cycle on the injectors? Have you directly wired your Walbro? It will definitely struggle with the stock wiring. BTW 345KW is a good effort.

[AngryRB]

Yes running out of fuel, the pump wiring was upgraded as he said it wasn't getting the full volts, so sounds about right then.

 

 

 

 

[GTSBoy]

Well, regardless of what the actual problem with the pump is, you cannot make more fuel out of thin air with a rising rate reg.

[admS15]

I think 1000cc injectors fed by a walbro 460 should be able to do 400rwkw on e85 easily. 

 

Im getting 310rwkw on e85 with 740cc inj and dw340 fp at around 85-90% duty cycle. The duty cycle should be a bit lower but my alternator is shitty and can't provide full voltage at high rpm. 

 

If you're getting the full voltage to your pump you should have plenty of fun fuel available for your power level.

[Dose Pipe Sutututu]

1000cc easy 400kW+ on E85, FWIW on my old shitbox setup I was at 90% DC (there abouts) with 875cc Siemens DEKA V with AFRs about 11.5 (gasoline scaling) and put out 372kW.