Which fuel pressure regulator

[LongBaz383BHP]

After a session at SRR it was identified that my Chim 500 was running lean higher up the rev range. Having resealed the plenum and replacing the pipe on the fuel regulator the problem is still there. It has not long had a 12,000 mile serve so the filter is new.
I was thinking of buying a fuel regulator that will up the pressure, but which one to buy?
Your thoughts and experiences would be greatly appreciated.
Thanks
Barrie

Edited by LongBaz383BHP on Friday 21st June 10:59

[QBee]

What injectors and AFM are you using? What BHPee is it making? Can you see where I'm going yet?

[SILICONEKID343HP]

LongBaz383BHP said:

After a session at SRR it was identified that my Chim 500 was running lean higher up the rev range. Having resealed the plenum and replacing the pipe on the fuel regulator the problem is still there. It has not long had a 12,000 mile serve so the filter is new.
I was thinking of buying a fuel regulator that will up the pressure, but which one to buy?
Your thoughts and experiences would be greatly appreciated.
Thanks
Barrie

Edited by LongBaz383BHP on Friday 21st June 10:59

Is your car supercharged or have a Turbo

[GasMunkey]

I've just bought a new one and really impressed with it, I'll ring you later

[LongBaz383BHP]

Thanks for the replies. No the car is not turbo or supercharged, I run NOS. The lean running was at N/A. It does make 313bhp without gas infact it ran well when on gas as there is petrol added.

[SILICONEKID343HP]

LongBaz383BHP said:

Thanks for the replies. No the car is not turbo or supercharged, I run NOS. The lean running was at N/A. It does make 313bhp without gas infact it ran well when on gas as there is petrol added.

You want to have word with Derek .

[QBee]

Ok,in the absence of an answer - I have just had exactly this issue, haven't I Alex?
The conclusion was that I was maxing out the stock AFM and injectors at about that level. Rob has changed the AFM for a P38 one, and the stock injectors for Bosch RedTop, and has removed my higher pressure fuel regulator and put in a standard one.
Car feels awesome, but I will get a definitive answer on the fuelling at about 11.30 tomorrow morning when it finishes on the rolling road and I have watched the AFR throughout.

[phazed]

From memory you want a rising rate regulator with the Lucas system.


If you are running MS or similar, a standard adjustable will do as the rising rate bit is taken into consideration by the MS.

I really do stand to be corrected here 'cause that's what I remember and my memory is crap!

[LongBaz383BHP]

The motor is running standard AFM and injectors. It was running fine but now doesnt. ?

[SILICONEKID343HP]

The standard pressure regulator is 1:1 linea not rising rate ,think its set at 2.5 bar .There is a vac pipe to the back of the plenum .

You can`t just fit an adjustable fuel regulator and up the pressure with the 14cux ,it will throw the whole map out !

If you have an after market ECU and want to up the fuel pressure the VE table will need reformatting .

Edited by SILICONEKID343HP on Friday 21st June 19:24

[QBee]

LongBaz383BHP said:

The motor is running standard AFM and injectors. It was running fine but now doesnt. ?

Sorry, cannot answer that, other than to say mine was fine on the road, where one rarely uses full throttle or max revs. The lean running only showed up on the track and on the rolling road.
On the track the symptom was a loss of further acceleration and torque at about 120 mph on the main straight at Snettetton. Alex did manage around 170 at RAF Marham.......where he had long enough to get there despite the fuelling.
The symptom Alex saw with mine on the RR was that the air fuel ratio went suddenly at about 4700 rpm from a healthy 14.7 to about 20-24 - it shot off the scale as if someone had thrown a switch. Apparently ths is what happens when the injectors and AFM go out of range. Standard TVR ones do this at 285 bhp or thereabouts. It was 286 on mine.
That's what I have found out in the last two months....
I am probably wrong anyway, everyone else is talking about fuel regulators.

Just out of interest, how did you find out it was running lean high up, and what did you feel about your engine before that?

[carsy]

SILICONEKID343HP said:

The standard pressure regulator is 1:1 linea not rising rate ,think its set at 2.5 bar .There is a vac pipe to the back of the plenum .

You can`t just fit an adjustable fuel regulator and up the pressure with the 14cux ,it will throw the whole map out !

If you have an after market ECU and want to up the fuel pressure the VE table will need reformatting .

[url]|http://thumbsnap.com/asjRd3Ek[/url

Edited by SILICONEKID343HP on Friday 21st June 19:24

i`d say your spot on there Daz. Its my understanding that its a 1:1 that is needed and not rising rate.

Edited by carsy on Friday 21st June 20:15

[LongBaz383BHP]

Found out at a TVR shoot out at Surrey Rolling Road. Have to say didnt notice any difference. Been on SRR before and all was fine. Only went this time for s bit of fun and a willey waving session. The only thing changed since the previous session was when the crank shaft pulley bolt snapped and therefor the cam timing could be out a smidge.

[blitzracing]

The earlier ECU's pre the 14CUX did not have fuel enrichment when accelerating and a rising rate regulator did improve things, so the likes of RPI proper-gated the myth that all set ups would benefit to sell more expensive bits, when in fact the 14CUX does it via programming just like the MS would. Fit one to a 14CUX as the ECU will simply spend more of its time correcting the mixture, and is of no benefit.

[SILICONEKID343HP]

QBee said:

Sorry, cannot answer that, other than to say mine was fine on the road, where one rarely uses full throttle or max revs. The lean running only showed up on the track and on the rolling road.
On the track the symptom was a loss of further acceleration and torque at about 120 mph on the main straight at Snettetton. Alex did manage around 170 at RAF Marham.......where he had long enough to get there despite the fuelling.
The symptom Alex saw with mine on the RR was that the air fuel ratio went suddenly at about 4700 rpm from a healthy 14.7 to about 20-24 - it shot off the scale as if someone had thrown a switch. Apparently ths is what happens when the injectors and AFM go out of range. Standard TVR ones do this at 285 bhp or thereabouts. It was 286 on mine.
That's what I have found out in the last two months....
I am probably wrong anyway, everyone else is talking about fuel regulators.

Just out of interest, how did you find out it was running lean high up, and what did you feel about your engine before that?

Mine maxed out at 300hp so i took advice and purchased these from the USA.

30Lb fiveo
http://www.ebay.co.uk/itm/30lb-315cc-FUEL-INJECTOR...

[LongBaz383BHP]

blitzracing said:

The earlier ECU's pre the 14CUX did not have fuel enrichment when accelerating and a rising rate regulator did improve things, so the likes of RPI proper-gated the myth that all set ups would benefit to sell more expensive bits, when in fact the 14CUX does it via programming just like the MS would. Fit one to a 14CUX as the ECU will simply spend more of its time correcting the mixture, and is of no benefit.

Thanks for that info. Is there any difference between a 4ltr and 5ltr regulator.

[blitzracing]

Nope. The regulator is there to dump excess fuel back to the tank- so the pump should have enough extra capacity to all ways supply more than the engine needs, and the rest gets recycled. The fuel rail should run at a constant 3 bar at full power, but if there is any restrictions in the fuel supply system liked kinked lines , blocked filters or under performing pumps (or low supply voltage) the mixture will progressively lean off as the engine load goes up. This is different to the injectors reaching the peak duty cycle, where they simply cant supply enough fuel in the provided opening time, so a sharper lean off of mixture will be seen, with the mixture being correct until this point is reached. In this case adding a couple of PSI to the fuel pressure will allow more fuel,(but no more as the injectors wont open properly if the pressure is to high) but it does this across the RPM range, so the ECU has to make bigger fueling corrections that it normally does. The 14CUX has a huge fuel correction range and will normally cope, although if the drive starts to shunt or snatch you may be pushing things to far. To be sure its not just a drop in fuel pressure you really need to attach a fuel pressure gauge to the take off point on the fuel rail, and check it holds steady at 3 bar under full load. Its quite normal for the fuel rail pressuure to be lower at less than full throttle, its designed to work this way.

Edited by blitzracing on Saturday 22 June 10:43

[phazed]

SILICONEKID343HP said:

You can`t just fit an adjustable fuel regulator and up the pressure with the 14cux ,it will throw the whole map out !

Edited by SILICONEKID343HP on Friday 21st June 19:24

I did with my Vectra injectors and the lucas system.

Had the fuel pressure changed on a rolling road until the best fueling was obtained.

TBH, the map was a bit ragged and rich at low revs but the driving was perfect.

[blitzracing]

This is the area I think you could correct by re calibrating the AFM output:


http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[macdeb]

Whichever regulator you go for stay well away from the FSE. I and many others had problems with them. Service is none existant, don't want to know.