Fuel Pressure Regulator Setting

Wajafly

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Hi guys,

Would like to seek expert opinion in the way we usually set our Fuel pressure Regulator.

I have bought Aerospeed Fuel Pressure Regulator which comes with a meter to see the psi. For my Waja, I have felt good with 43 psi. However, at one time after I ported my intake manifold, the pressure ran to 45psi.

Thus, I requested the mechanic to help lower it down to 43psi. He unplugged my vacumn hose and basically the pressure went to 50 and above. Then, from there he lower to 43psi. After that he plug the hose back and my car jerk and dies off.

When I question that power-bengkel boss, he says it is a normal procedure of tuning the fuel pressure regulator? True or not? Got like that one meh?
 

Wajafly

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Thx again huakenny,

I have AF meter. Car is running with SAFC2 and SITC. The engine is running on Mat Speed cams and ported polished head from there as well. The use of fuel pressure regulator does helps in performance to my car. Wrongly set and I can lose up to 1 second on 0-100m and 3 seconds in 0-400m. True or not? I timed it with my Pivot speed meter.

What is the best way to set our fuel pressure regulator setting? And why do we need an AF meter to set it? It only affects the pressure of fuel right? How could the AF ratio be affected by that?
 

GT20v

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dude,
set ur FP the max ur fuel pump can deliver without compromise the flow..and then tune the AFR down or according to your preference........well around 13 for NA.......best do it on a dyno...

how to see ur fuel pump????run the engine check the FPR at 40psi let the fuel flow in a mesurement tank...check the flow in 60sec.......a good fuel pump flow 2-3liter@40psi per min..

good luck....by the look of ur car..it does sound fast...whats the cam duration n lift?
 

GT20v

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What is the best way to set our fuel pressure regulator setting? And why do we need an AF meter to set it? It only affects the pressure of fuel right? How could the AF ratio be affected by that?

AFR meter is for your to see your AF ratio..its not 100% accurate hence the existance of the wideband o2 meter....the higher u running ur fuel pressure the richer ur AFR...since it push the fuel in more.....all OEM ecu is tune based on a predetermine fuel pressure..im not sure how many is that..but certain car maker do release this kind of info..maybe u can check it out......
 

EFN

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There is two way to tune A-FPR, First, simply adjust it while the vacuum hose is connected at idle - you will be tuning the start point. Secondly, which is much more accurate is to disconnect the vacuum hose first, you will be tuning Full Throttle setup, which is generally higher than the Idle start point.

Standard WAJA uses 43.5 PSI at Idle with Vacuum hose connected - this means that Full throttle pressure is at around 53 - 54PSI. The majority of my WAJA EFcustoms A-FPR customers run 47 to 50PSI at Idle and Full Throttle at 57 to 60PSI - and most of them are running Stock Standard setup with minor mods - and the results are good, very good in fact. But some WAJA does run very well with lower pressure, even as low as 32PSI Idle/42PSI WOT - I don't know how to explain this but I suspect that it has to do a lot with engine condition and driving style.

So when you say that your mech tune to 43PSI with the vacuum hose disconnected, he is actually tuning WOT at 43PSI, so when the Vacuum hose is reconnected the Idle pressure would be at around 33PSI in fact - way too low for heavily modified WAJA like yours.

* On the other hand, Any Fuel Injected cars can always benefit from A-FPR tuning (standard or modified), not necessarily to increase pressure, but in reality most of them used it to reduce Fuel Pressure to achieve optimal fuel feed.
 

ijoe

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cheer EFN aka wandi...urs AFR installed in my car still working in good condition...setting at stock setup 40psi...and 43psi when want to vrommm...vrommm....
good job bro...
 

EFN

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huakenny said:
wat d main purpose of fuel regulator>? if d car is standard? no point to put it rite? corect if im wrong
Fuel injection system require pressurized fuel to go through the injectors. ECU will only send signal to open or close the injectors based on whatever input it gets from the sensors. So by default almost all EFi cars uses Fuel Pressure Regulators at the return line path to regulate the desired pressure by the manufacturer. Typically from factory, pressure is always pre-set high to help enriching the mix to ensure that knocking/pinging are eliminated. But too rich a mix will also cause most cars bogs down and slow in response.

For tuners and car enthusiast, the opportunity to use an Adjustable Fuel Pressure Regulator presents some sort of control on the output. This is applicable regardless in what state your car are in - modified or non modified - u still need pressurized fuel else the injectors will not be able to get fuel pass through it. The right amount of pressure will definitely makes the engine happy.

* but nowadays I have seen a lot of new cars does not use Fuel Return System so it has to be that they use some sort of intelligent fuel pump that regulate pressure as required.
 

doktahu

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wajafly.. can u give me standard setting for 1.6 sohc engine??.. i've been using this for a while ( my fren insatlled to for me).. but i don feel any different from b4 unless hard to start eve after long driving.. My presure meter show at 30 psi..
 

Wajafly

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First of all, thank you to everyone who replied to me with great advises like EFN and GT20v.

GT20v, I don't know the cam lift duration but should be around 270 and below maybe? Got no idea and just guessing. The difference is great with P+P. For my Auto, I can say it is faster than standard Waja but NOT good enough to race with any stock GTI or Perdana. However, I am happy with the excellent service and product of MatSpeed.

EFN, thanks for the great tuning reference on FPR setting. Yeah... with the hose disconnected and set to 43, my car chokes like hell and dies off. He (the so claimed professional / engineer boss from power bengkel) says it is a normal procedure of tuning that way. Even when I mentioned what his mechanic did, he says it is normal to him. I had that conversation recorded if you guys don't believe me.

Well, I suspect my engine dies off firstly because of wrongly adjusted FPR setting, but the mechanic seems to think the sensors might be dirty. So, he disconnected the connectors from boost sensor and took the high pressure air gun and sprayed into the sensors connectors including directly at the sensor while it's being attached. That is where I suspect causes permanent damage to my boost sensor on top of my Intake manifold which after that, my car not able to start again even after FPR has been adjusted correctly... Sigh... what a Power-Bengkel it is... I have so much high hope in them based on their nice sweet talking website... Sigh... I am still filling up my Tribunal Court of Claims forms...

Doktahu, I think EFN also mentioned it is about 43.5 PSI for normal Waja. I heard this setting from a friend as well. Funny, I feel good at 43 as well. Maybe a little higher will give better performance? How high is too high? I heard that Waja is running on high compression already. Maybe that's why we run on lower PSI instead?
 

doktahu

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Wajafly said:
First of all, thank you to everyone who replied to me with great advises like EFN and GT20v.

GT20v, I don't know the cam lift duration but should be around 270 and below maybe? Got no idea and just guessing. The difference is great with P+P. For my Auto, I can say it is faster than standard Waja but NOT good enough to race with any stock GTI or Perdana. However, I am happy with the excellent service and product of MatSpeed.

EFN, thanks for the great tuning reference on FPR setting. Yeah... with the hose disconnected and set to 43, my car chokes like hell and dies off. He (the so claimed professional / engineer boss from power bengkel) says it is a normal procedure of tuning that way. Even when I mentioned what his mechanic did, he says it is normal to him. I had that conversation recorded if you guys don't believe me.

Well, I suspect my engine dies off firstly because of wrongly adjusted FPR setting, but the mechanic seems to think the sensors might be dirty. So, he disconnected the connectors from boost sensor and took the high pressure air gun and sprayed into the sensors connectors including directly at the sensor while it's being attached. That is where I suspect causes permanent damage to my boost sensor on top of my Intake manifold which after that, my car not able to start again even after FPR has been adjusted correctly... Sigh... what a Power-Bengkel it is... I have so much high hope in them based on their nice sweet talking website... Sigh... I am still filling up my Tribunal Court of Claims forms...

Doktahu, I think EFN also mentioned it is about 43.5 PSI for normal Waja. I heard this setting from a friend as well. Funny, I feel good at 43 as well. Maybe a little higher will give better performance? How high is too high? I heard that Waja is running on high compression already. Maybe that's why we run on lower PSI instead?
thanks for the info guys.. me kinda blur about this thing..
 

GT20v

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wajafly,

dont mention it..there is some people here still know about car hehehe..
actually for me the correct way to tune is to tune it WITHOUT vacuum connected..tahts what i always did..the downturn is ,u have to know ur original setting..hehe or reduce it slowly from the higher psi.......

a 270 duration is nice..but quite high for normal auto car...heheh.did u install the adj cam pulley?running 8+krpm? hehehe nice..i wish i can get a cam like urs..........get a bigger valve..and slower than GTi???are you pulling my leg???hahhaa

sifu EFN power!!.........heheh