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Rising rate FPR

AngryRB

By AngryRB,
in Engines & Forced Induction

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AngryRB Grand Master

AngryRB

Posted
Posted (edited)

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 by AngryRB
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Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

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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.

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KiwiRS4T Grand Master

KiwiRS4T

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2 hours ago, 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?

 

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.

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Murray_Calavera Mentor

Murray_Calavera

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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?

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AngryRB Grand Master

AngryRB

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Posted (edited)

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 by AngryRB
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KiwiRS4T Grand Master

KiwiRS4T

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"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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AngryRB Grand Master

AngryRB

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24 minutes ago, 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?

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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Murray_Calavera Mentor

Murray_Calavera

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6 hours ago, 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.

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. 

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AngryRB Grand Master

AngryRB

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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 by AngryRB
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KiwiRS4T Grand Master

KiwiRS4T

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31 minutes ago, 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...

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.

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admS15 Grand Master

admS15

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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.

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