stronger pump increasing fuel pressure?

[Crunk81us]

So the in tank pump has an internal pressure regulator.. ok got it.

But is it possible adding a higher flowing pump could actually bump up the pressure by out flowing the regulator?

has anyone noticed a bump in pressure (even a small one) by putting bigger pump in?

something like this :

http://www.ebay.com.au/itm/Genuine-W...AAAOSwk1JWeLhj

[zkv476]

It can and does happen if you run too small of a regulator and too big a pump. Whether or not it will happen with that particular pump I have no idea but it can happen. However that pressure will only be higher at lower loads. As you start consuming the fuel quicker and bypassing less of it the pressure will start dropping down to the spring pressure. This happened on an S2000 that belongs to my buddy.

Originally Posted by Crunk81us

So the in tank pump has an internal pressure regulator.. ok got it.

But is it possible adding a higher flowing pump could actually bump up the pressure by out flowing the regulator?

has anyone noticed a bump in pressure (even a small one) by putting bigger pump in?

something like this :

http://www.ebay.com.au/itm/Genuine-W...AAAOSwk1JWeLhj

[Crunk81us]

Originally Posted by zkv476

It can and does happen if you run too small of a regulator and too big a pump. Whether or not it will happen with that particular pump I have no idea but it can happen. However that pressure will only be higher at lower loads. As you start consuming the fuel quicker and bypassing less of it the pressure will start dropping down to the spring pressure. This happened on an S2000 that belongs to my buddy.

after posting this i did some more reading, and yeah i think youre right this is exactly what would happen.. back to the drawing board lol

[Tcoat]

Not a sarcastic answer but a real question:

What are you trying to gain with a stronger pump? The system is already a loop with most of the fuel pumped to the engine returned to the tank. The flow probably already exceeds the most stringent demands the injection system could put on it.

[steve99]

Originally Posted by Tcoat

Not a sarcastic answer but a real question:

What are you trying to gain with a stronger pump? The system is already a loop with most of the fuel pumped to the engine returned to the tank. The flow probably already exceeds the most stringent demands the injection system could put on it.

It an 86 series car with locked motec ecu and the tune is pretty ordinary its running 13 AFR at WOT high rpm on petrol.


Unfortunalty its a one size fits all tune and they wont alter it.


he was going to try a maf sensor from an earlier model car (which the tune was probably developed on) as it may be differences in maf sensor causing it to run lean, aparantly its happened to a few guys.

[Tcoat]

Originally Posted by steve99

It an 86 series car with locked motec ecu and the tune is pretty ordinary its running 13 AFR at WOT high rpm on petrol.


Unfortunalty its a one size fits all tune and they wont alter it.


he was going to try a maf sensor from an earlier model car (which the tune was probably developed on) as it may be differences in maf sensor causing it to run lean, aparantly its happened to a few guys.

Thanks Steve. I understood the maf part but can you translate that first line to somethin that a guy that hasn't even read Tuning For Dummies can understand. There are loads of things I know but electronic tuning is way beyond my skill set and that first line may as well be in Chinese to me (I do know what the ECU is of course). So how would more pressure help?

Need my daily learn something fix.

[steve99]

Originally Posted by Tcoat

Thanks Steve. I understood the maf part but can you translate that first line to somethin that a guy that hasn't even read Tuning For Dummies can understand. There are loads of things I know but electronic tuning is way beyond my skill set and that first line may as well be in Chinese to me (I do know what the ECU is of course). So how would more pressure help?

Need my daily learn something fix.

ok with these 86 series car.


to supposedly keep things fair
The cars all run a control ECU
The ECU chosen was a MOTEC likely as its likely less hackable than the stock ECU
a tune was developed on a test car.


This tune was then adopted as the standard and given to all.
unfortunaly some cars run 10% richer/leaner than others, it likely due differences in MAF sensors .


unfortunaly it appears the tune was developed on a car that was different to many of the likely newer model cars.


The organisers don't want to change or allow custom tuning so some guys are stuck running quite lean and down on power and likely considerable knock further reducing power.

[churchx]

But can they log on those series cars? Then maybe they can try to game/manipulate MAF with changing sensors, slight changes to intakes, to get things right with that stock tune?

[GSpeed]

So the ECU isn't running closed-loop lambda? Seems like you should be petitioning the governing body for that. M150 (I'm assuming, since it's P&P) shouldn't have any problem keeping lambda in check, even with minor differences in sensors.

[nikitopo]

Originally Posted by steve99

This tune was then adopted as the standard and given to all.
unfortunaly some cars run 10% richer/leaner than others, it likely due differences in MAF sensors .

unfortunaly it appears the tune was developed on a car that was different to many of the likely newer model cars.

I didn't know about this change in MAF sensors. Which year happened? 2015?


EDIT: Is it the discussion in this topic ?http://www.ft86club.com/forums/showthread.php?t=106538

[OkieSnuffBox]

^Is it a change, or acceptable manufacturing tolerance?

[nikitopo]

We know that there were some actual changes mid of 2013 for the 2014 models and onwards. Check here:

http://www.ft86club.com/forums/showp...6&postcount=81

I wasn't aware of any other changes.

[Spartarus]

Originally Posted by Tcoat

Thanks Steve. I understood the maf part but can you translate that first line to somethin that a guy that hasn't even read Tuning For Dummies can understand. There are loads of things I know but electronic tuning is way beyond my skill set and that first line may as well be in Chinese to me (I do know what the ECU is of course). So how would more pressure help?

Need my daily learn something fix.

I see nobody answered your question yet.

The same injector, on the same pulsewidth*, will flow more fuel as you increase the fuel pressure.

* (the signal that controls how long it is open)

[scmil95eg]

Originally Posted by Spartarus

I see nobody answered your question yet.

The same injector, on the same pulsewidth*, will flow more fuel as you increase the fuel pressure.

* (the signal that controls how long it is open)

Yep.

To calc flow:
New Pressure / Old Pressure [Square Root] * Old Flow

Example; 600cc/min @ 45 psi - what will it flow at 55psi?

55/45=1.2222222 [SqRt] = 1.1055415 * 600 = 663.32 cc/min