How much fuel pressure?

[Charlie Thompson]

Morning guys, looking at putting an aftermarket fuel pressure regulator on my glanza. Does anybody know what setting the fuel pressure should be set at? 
 

cars running standard boost CT9, fmic, 3inch exhaust, 255lph fuel pump. 
 

thanks 

[Sam44]

I've recorded 2.8bar to 3bar regulated (vacume pipe attached) pressure on the standard fuel reg, and 3.2 unregulated vacuum pipe off). 

[RobSR]

Stock is 2.4 bar 

[Charlie Thompson]

Thanks for the reply’s lads 

[Sam44]

3 hours ago, Charlie Thompson said:

Thanks for the reply’s lads 

Your welcome. I've only tested about 4 factory regs. The one that measured 2.8bar didn't increase the pressure so I would say that one was nakered. The others have been 3bar regulated. 

[Patches]

4 hours ago, Sam44 said:

Your welcome. I've only tested about 4 factory regs. The one that measured 2.8bar didn't increase the pressure so I would say that one was nakered. The others have been 3bar regulated. 

All on the same car? With what pump?

[Sam44]

No all different, factory units I believe. 2x gt turbos 1x ep91. 

I have also done my ukEp91 and the paseo they also were set at 3bar regulated. My ep91 was on a adjustable fpr sporting a kemso aftermarket pump. The paseo was totally factory. 

Also when I search denso injectors on line for part numbers/cc delivery it always references 3bar fuel pressure for that delivery rate. 

Most petrol common rail injection of this era operates at this pressure, so not really a suprise. 

It would be great if other could test there factory pressure to confirm my readings. 

Edited January 25, 2022 by Sam44

[Claymore]

Just to add my research to this thread for 4efe. Have not measured on an actual vehicle yet.

The 4efe (gen 2) Starlet 96-99, 4efe (gen 1) corolla 92-97 and 4efe (gen 3) corolla 97-99 and 5efe Paseo 95-99, all list the same fpr part number (23280-11070).

There is no Starlet Haynes manual but there are for the 'rolla's. (92-97 rolla shown below)

Both Haynes manuals show a base fuel pressure of about 2.8bar and manifold referenced fuel pressure at idle of about 2.4 bar. That is what the Haynes manual states is correct.

Can't say for the 4efte as it uses a different reg (23280-11040).  If someone can ask Jay on the other forum (I'm not a member), he may be able to check in the official Toyota workshop manual he has for the Toyota 4efte data.

Let's not forget the age of some of these Toyota fpr's and fuel systems aswell (clogged filters, weak pumps, clogged returns etc.)

Edited January 26, 2022 by Claymore
Clarity

[Sam44]

Great information as always. 

Love this, the 4efe/5efe do look slightly different.

I didn't measure any of the ones I did under boost conditions either I just snapped the throttle open. The ones that responded hit about 3.2bar. all the same near anuff. 

Edited January 25, 2022 by Sam44

[Patches]

Point is, what you "measured" is irrelevant, there are many factors which could affect the readings (age of parts, accuracy of measuring tools, technique, aftermarket parts etc). 

People don't need made up random shite for answers, if you don't know what it should be then you don't have to answer.

[Sam44]

At least I've measured them. That's what I go off. Auto data is not always right. 

For instance if I drop my 5efe or 4efe+t pressure bellow 2.5bar all the plugs become fouled with cement boil. this is fuel as a luquid boiling off the plug surface (poor injector atomisation). 3bar is the point at which there's a big improvement. 

Any one that would like to do the same and comment please do. This is a good topic of interest. 

I have also seen a tuning development setup and there fuel regs are set at 3bar on factory injectors, emanage blue piggy back. 

What claymore has put up is a valid point. Also when I first started researching factory pressure 2.4bar was the answer.

Have you?.

Or is that you on your period. Give that keyboard a bash. It's your comment that is not helpful. 

Edited January 26, 2022 by Sam44

[Patches]

12 hours ago, Sam44 said:

At least I've measured them. That's what I go off. Auto data is not always right. 

For instance if I drop my 5efe or 4efe+t pressure bellow 2.5bar all the plugs become fouled with cement boil. this is fuel as a luquid boiling off the plug surface (poor injector atomisation). 3bar is the point at which there's a big improvement. 

Any one that would like to do the same and comment please do. This is a good topic of interest. 

I have also seen a tuning development setup and there fuel regs are set at 3bar on factory injectors, emanage blue piggy back. 

What claymore has put up is a valid point. Also when I first started researching factory pressure 2.4bar was the answer.

Have you?.

Or is that you on your period. Give that keyboard a bash. It's your comment that is not helpful. 

I haven't measured it in stock form no, at what point did I say I did? I've not tried to answer his question as I honestly don't know. I do have a Link 150 psi sensor on my fuel line and I have a wideband sensor, which is far superior than reading plugs, but my ECU is aftermarket and my fuel pump is the TD 340ltr/hr and the stock reg can't handle the pressure so any readings I have are absolutely pointless to share.

If the pumps and regs you have apparently measured on this random fuel pressure data collection mission you went on with 3 cars you don't own... they are 20+ year old stock items I would take those readings with a pinch of salt, I also doubt you have opened each of the fuel tanks to check they all have the stock pumps.

I see you on here all the time offering "advice" and it seems to me that it's more important for to you to help people than it is for them to get the right answers. This is dangerous as wrong advice on some of these topics can be costly mistakes for others.

[Charlie Thompson]

When setting my fuel pressure regulator up do I do this with the vacuum line on or off? 

[Sam44]

Do it with the vacume line on. The setting you are being given here are with the vacume line on. 

Check the pressure settings have stayed the same after a run and the engine has got up to operating temp. 

Edited January 30, 2022 by Sam44

[RobSR]

On 1/28/2022 at 7:27 PM, Charlie Thompson said:

When setting my fuel pressure regulator up do I do this with the vacuum line on or off? 

Traditionally you set them with the vac line off so you're setting the true base pressure 

[Sam44]

Rob is the 2.4bar you answered previously (first comment) with the vac line on or off. The previous answer I'd geuss off. 

In my answers I put vacume line on and off reading. 

Edited January 30, 2022 by Sam44

[Charlie Thompson]

2 hours ago, RobSR said:

Traditionally you set them with the vac line off so you're setting the true base pressure 

Hi rob do you know what is the best pressure for a pretty much standard 4efte with vac line off? Is it the 2.4 bar you stated? 

Edited January 30, 2022 by Charlie Thompson

[RobSR]

2.4 was with vac line on as most people test them with the car running so naturally the vac line is still on as with stock ECU you can’t really run the pump without starting it unless you go into the Diagnostics block, but as said, best practice you should set it with the vac line removed, in which case set it at approx 2.8 bar.

 

 

 

[Sam44]

What fpr have you got. The eBay regs only drop .2bar'ish (vacume line on) after setting it with it off. fse, and areomotive drop around 1bar. Sard and turbosmart do around .4 to.6bar. do you have a boost gauge that runs into vacume reading. If so can you tell me your idle speed at operating temp and vacume figures.

Let us know if it drops to 2.4bar with the vacume line on. 

This is purely out of interest for me. I'm intrigued in how little info Rob needs. Quite impressive. 

As said purely out of interest I'm really not here to argue. 

If you want a nice hp hit the magic fuel pressure figure is 3.6bar setting it with the vacume line off. At 1bar turbo boost on a ct9b I've seen a lad hit the magic 200hp. With the basic supporting mods, but it works just as good on standard boost yeilding around 160 to 170hp. 

Please keep checking your pressure everyday for at least 1 week they will stabilise/alter after the fuel line has been opened.

I will need a plug read/pic to see how hot the exhaust/cylinders are running. 3.6bar is typically safe on these. 

If you want to try it after rods pressure figures. You will see what I mean. 

If you do I'm on wats app I can help you tune it. Or I'm on here but with company if you now what I mean. 

Please reply with your results. We can start to put things to bed around the fpr. 

There is another great trick using a vw vacume chamber on the fpr vac line. I can show you, this helps the fueling around the turbo spool up point. Giving some kick ass spool up response. Very noticeable on the ct9b, ct9 hyb, tdo4l. 

This idea/bit of tec was taken off the Celica 3sge 2ltr running it's very clever multistage inletmanifold. Also I've found it on the MK1 MR2 4age multistage inlet. 

So I'm very confident it will also help benafit the 4efe lads on a adjustable fpr. 

Thew for these lads you have to run the pink 4age/7afe/5efhe 230cc injectors running around 2.5 to 2.7 bar fuel pressure setting it up with the vacume line on. Some more kick ass power. Use the eBay aero motive copy fpr these only add around .2bar of fuel pressure on throttle great for the 4efe and bigger injectors not to go to high, just for good fueling. On the short turn fuel trim, the long term closed loop trim will more are less be the same at operating temp as on the factory 198cc green units.

For the turbo lads the fse is the one to get. 

The 230cc pink denso injectors are only 2 steps up on the denso injector size so you can reduce the fuel pressure to hit the sweet spot. These injectors are found on every Toyota of this era at and above 100hp to around 140hp, abit like jetiing a carb.

Edited January 31, 2022 by Sam44

[RobSR]

7 hours ago, Sam44 said:

What fpr have you got. The eBay regs only drop .2bar'ish (vacume line on) after setting it with it off. fse, and areomotive drop around 1bar. Sard and turbosmart do around .4 to.6bar. do you have a boost gauge that runs into vacume reading. If so can you tell me your idle speed at operating temp and vacume figures.

Let us know if it drops to 2.4bar with the vacume line on. 

This is purely out of interest for me. I'm intrigued in how little info Rob needs. Quite impressive. 

As said purely out of interest I'm really not here to argue. 

If you want a nice hp hit the magic fuel pressure figure is 3.6bar setting it with the vacume line off. At 1bar turbo boost on a ct9b I've seen a lad hit the magic 200hp. With the basic supporting mods, but it works just as good on standard boost yeilding around 160 to 170hp. 

Please keep checking your pressure everyday for at least 1 week they will stabilise/alter after the fuel line has been opened.

I will need a plug read/pic to see how hot the exhaust/cylinders are running. 3.6bar is typically safe on these. 

If you want to try it after rods pressure figures. You will see what I mean. 

If you do I'm on wats app I can help you tune it. Or I'm on here but with company if you now what I mean. 

Please reply with your results. We can start to put things to bed around the fpr. 

There is another great trick using a vw vacume chamber on the fpr vac line. I can show you, this helps the fueling around the turbo spool up point. Giving some kick ass spool up response. Very noticeable on the ct9b, ct9 hyb, tdo4l. 

This idea/bit of tec was taken off the Celica 3sge 2ltr running it's very clever multistage inletmanifold. Also I've found it on the MK1 MR2 4age multistage inlet. 

So I'm very confident it will also help benafit the 4efe lads on a adjustable fpr. 

Thew for these lads you have to run the pink 4age/7afe/5efhe 230cc injectors running around 2.5 to 2.7 bar fuel pressure setting it up with the vacume line on. Some more kick ass power. Use the eBay aero motive copy fpr these only add around .2bar of fuel pressure on throttle great for the 4efe and bigger injectors not to go to high, just for good fueling. On the short turn fuel trim, the long term closed loop trim will more are less be the same at operating temp as on the factory 198cc green units.

For the turbo lads the fse is the one to get. 

The 230cc pink denso injectors are only 2 steps up on the denso injector size so you can reduce the fuel pressure to hit the sweet spot. These injectors are found on every Toyota of this era at and above 100hp to around 140hp, abit like jetiing a carb.

You’re saying it’s ‘impressive’ that I don’t need to know the exact FPR the guy is running - that’s because whatever FPR you run, the pressure changes based on the engine vacuum not the FPR - if someone fits an eBay / faulty / shit FPR that doesn’t alter the fuel pressure correctly based on the engine vacuum and boost - that’s not my problem. 
 

It’s all standard stuff, it doesn’t need to be over complicated. 
 

Talking of ‘impressive’ telling the chap to run 3.6 bar fuel pressure and it’ll make 200bhp is a bigger stab in the dark when you have no idea on his setup.

The stock ECU runs stupidly rich with a CT9 on stock ECU with stock fuel pressure with bolt ons (decat, filter and exhaust) - they run flat 10s on boost, let alone doing that with 3.6 bar fuel pressure, it’s only going to get worse.
 

This advice is the exact reason why @Patches has called you out above - rightly so too. 
 

Last CT9 turbo car I mapped made 200 bhp at the fly at 1 bar, guess what; it had a stock FPR so the base fuel pressure was no where near 3.6 bar - I wonder how that was possible? Oh yes, because the FP doesn’t need to be anywhere near 3.6 bar base

[Charlie Thompson]

21 minutes ago, RobSR said:

You’re saying it’s ‘impressive’ that I don’t need to know the exact FPR the guy is running - that’s because whatever FPR you run, the pressure changes based on the engine vacuum not the FPR - if someone fits an eBay / faulty / shit FPR that doesn’t alter the fuel pressure correctly based on the engine vacuum and boost - that’s not my problem. 
 

It’s all standard stuff, it doesn’t need to be over complicated. 
 

Talking of ‘impressive’ telling the chap to run 3.6 bar fuel pressure and it’ll make 200bhp is a bigger stab in the dark when you have no idea on his setup.

The stock ECU runs stupidly rich with a CT9 on stock ECU with stock fuel pressure with bolt ons (decat, filter and exhaust) - they run flat 10s on boost, let alone doing that with 3.6 bar fuel pressure, it’s only going to get worse.
 

This advice is the exact reason why @Patches has called you out above - rightly so too. 
 

Last CT9 turbo car I mapped made 200 bhp at the fly at 1 bar, guess what; it had a stock FPR so the fuel pressure was no where near 3.6 bar - I wonder how that was possible? Oh yes, because the FP doesn’t need to be anywhere near 3.6 bar

Thanks for the input mate. I’ve bought a sytec fuel pressure regulator, I was told that it would be good for the job, would this be the case? 
 

while I’m on sorry for causing abit of a stir 😬 

[RobSR]

3 minutes ago, Charlie Thompson said:

Thanks for the input mate. I’ve bought a sytec fuel pressure regulator, I was told that it would be good for the job, would this be the case? 
 

while I’m on sorry for causing abit of a stir 😬 

It should be fine yes.

Haha don’t apologise, not your fault, as with any forum, it’s free speech as such so just different people giving their advice. 
 

Up to you whos you want to follow!

[Sam44]

Charlie try it bro. Put us to the test.

.its about fuel atomisation with the stock injectors, altering fuel pressure does not alter fuel delivery by a massive amount.  

Members, You be the judge. It's what I call a sweet spot. 

Rob read my post. It's all in there. Half of what you said There is in my post, 

Basic supporting mods for a ct9 at 1bar is, fmic, aftermarket Exhaust system & decat (this includes an aftermarket exhaust manifold or a ported out factory Unit), hks turbo actuator, fcd/ECU,ported ct9 waste gate, after market induction kit/removal of the stock turbo intake/hot pipe/efi pipe. Now run 3.6bar on your fpr (set up with vacuum pipe off) and even on a fcd you will be very close to 200hp. Of course this is if everything is healthy and engine setting are correct. Trust me

And guess what rob we don't need your expensive maps or ECUs to hit 200hp, crazy or what. 

Let's see do I buy a fpr or ecu? £. 

Charlie do not worry about us we are big boys. Just try it and let us know what you think. I can see me and him doing this for awhile. 

There is 1 eBay reg I've come across that people should avoid. This regs pressure is by no means stable.  

"Aluminum Alloy Universal FPR Fuel Pressure Regulator with Gauge Hose 0-140psi | eBay" https://www.ebay.co.uk/itm/203091572954?hash=item2f493378da:g:ayEAAOSwdqhfSa8d

Horible regs these. 

Edited February 1, 2022 by Sam44

[RobSR]

1 hour ago, Sam44 said:

 

And guess what rob we don't need your expensive maps or ECUs to hit 200hp, crazy or what. 

 

I didnt say you did, however its a lot safer and driveability is miles better.

[Sam44]

Yeh with all respect it's Two ways of achieving the same hp. Possibly with different driveability results, And yeh these factory engine control units do run rich, I suppose it's why there safe on a fcd at 1bar. The denso injectors really quite poor.

For The vacume chamber fpr mod. Requires a vw vac chamber, 3x "T" offs, 1x a inline reducer insert, and 1x one way valve. Giving nicer faster sharper turbo spool up. Give us a message on here. 

Edited February 1, 2022 by Sam44