Pre-facelift R53 Boost Pressure

[Silent1]

Is there anyone on here with a pre-facelift R53 with the original supercharger fitted and a boost gauge?

If so what pulley do you have and what pressure are you seeing?

I've got an Alta 17% fitted and at WOT i'm only seeing 14-15psi, now i'm sure it should be higher leading me to think a 15% may have been fitted by mistake.

If you've got a newer teflon coated supercharger can you let me know the pressure you're seeing as well.

[Tigger, Eeyore & Roo]

I don't have a boost guage fitted, but I've previously read on tuning threads that the standard boost is around 8 psi.

[Jaw_F430]

Quote: Originally Posted by Silent1 (original)

Is there anyone on here with a pre-facelift R53 with the original supercharger fitted and a boost gauge?

If so what pulley do you have and what pressure are you seeing?

I've got an Alta 17% fitted and at WOT i'm only seeing 14-15psi, now i'm sure it should be higher leading me to think a 15% may have been fitted by mistake.

If you've got a newer teflon coated supercharger can you let me know the pressure you're seeing as well.

Facelift model and on the dyno with 15% I seen 16.67psi, after fitting new RMW head I see 14-15psi on boost gauge (not been at WOT yet though)

[MINI-Morgan]

What other mods do you have? More importantly head, cams, manifold and especially intercooler. With a large intercooler you should be hitting 18+psi at the red line in 3rd. With the stock intercooler its about 2-3psi less from my experience.

[Silent1]

GRS Intercooler
440cc injectors
adjustable regulator (undecided if it's staying on)
cooler plugs
Janspeed cat-back

I've just bought a new teflon coated supercharger though as i want to change it, well more precisely i'm going to ask 1320 to change it

[MINI-Morgan]

I would expect 17-18psi then with your current setup. A good intake is a small bonus to reduce the vacuum in the intake.

[Silent1]

Yeah, i'm currently waiting on my alta v2 intake and janspeed manifold turning up, i'm fairly sure the standard airbox isn't helping. The only thing i'm undecided on is the AFPR as i didn't have the boost gauge installed before i put it on, but i lost all the pops and crackles when it went on, so i've definately lost some cylinder cooling from that, possibly some boost pressure as well through it trying to adjust to the correct AFR

[MINI-Morgan]

Quote: Originally Posted by Silent1 (original)

Yeah, i'm currently waiting on my alta v2 intake and janspeed manifold turning up, i'm fairly sure the standard airbox isn't helping. The only thing i'm undecided on is the AFPR as i didn't have the boost gauge installed before i put it on, but i lost all the pops and crackles when it went on, so i've definately lost some cylinder cooling from that, possibly some boost pressure as well through it trying to adjust to the correct AFR

Did you find a big improvement in fuel economy? Its strange really as the fueling is closed loop for normal driving so should be adjusting to maintain the correct AFR unless its seriously lean it can compensate enough. But then I havent played with one yet to know how much you can adjust. Just the standard flow which then offsets the boost controlled flow??

[Silent1]

Fuel economy has gone down slightly, it's definately not gone up.

Standard fuel pressure is 3.5 bar
It came set to 3.0 bar which is the recommended setting for 440cc injectors, without the spacer it's maximum is 3.2 bar, to get it any higher you need to fit a spacer, but this then means you can raise it up to 4.5 bar, so without a gauge there's no way for me to check the fuel pressure, so my only option is to refit a standard pressure regulator and see if i get any changes.

ETA, as for the closed loop, this is the problem i think, with the pressure drop the injectors aren't as efficient at atomising the fuel, therefore it's putting more in and running it rich.

[minioneandrew]

I have a 15% pulley and see 16 psi max at WOT!
Regards
Drew

[Lucky Dave]

On the subject of the AFPR, I have fitted and setup many of these. Without a good air/fuel gauge you are guessing in the dark. With the larger injectors your running you will need to reduce the fuel pressure from stock or you will run very rich. Im sure in your instructions with the unit it did mention this?

I set one just this week and the fuel pressure is now down to about 36 psi and the car runs sweet, on my car its set to about 40 psi.
All my findings about boost pressure are just the same as Minimorgans so I would say thats going to be the norm.

[Rigsey]

With my 17% pulley I usually see a max of 17 psi occasionally 18psi

[Lucky Dave]

Quote: Originally Posted by Silent1 (original)

Fuel economy has gone down slightly, it's definately not gone up.

Standard fuel pressure is 3.5 bar
It came set to 3.0 bar which is the recommended setting for 440cc injectors, without the spacer it's maximum is 3.2 bar, to get it any higher you need to fit a spacer, but this then means you can raise it up to 4.5 bar, so without a gauge there's no way for me to check the fuel pressure, so my only option is to refit a standard pressure regulator and see if i get any changes.

ETA, as for the closed loop, this is the problem i think, with the pressure drop the injectors aren't as efficient at atomising the fuel, therefore it's putting more in and running it rich.

The pressure drop will put less fuel in.

Its simple bigger hole injector needs less pressure to deliver the same fuel.

The other option is to increase the pressure on stock injectors, but your fuel pump will be maxed so its cheaper and easier to inlarge the injector size AND reduce the pressure, if you dont reduce the pressure buy running a stock reg then you will be even richer.

[MINI-Morgan]

Quote: Originally Posted by Lucky Dave (original)

The pressure drop will put less fuel in.

Its simple bigger hole injector needs less pressure to deliver the same fuel.

The other option is to increase the pressure on stock injectors, but your fuel pump will be maxed so its cheaper and easier to inlarge the injector size AND reduce the pressure, if you dont reduce the pressure buy running a stock reg then you will be even richer.

Clear out your PMs DAVE!

[BigShow]

I've seen 15-16 psi on mine and only hit 18 psi at 8.2k rpm