Fuel regulator VS Rising rate (Power Boost Valve)

[matt-man]

Hi All,

I havent updated the ongoing 'fun' with the wedge recently, but Ed Crouch and I think we might have got to the bottom of the problem which is around fueling.

All of the injectors are out and have bee sent away for a full service - hopefully they will be back shortly!

Anyhow - We also think I should change the regulator at the same time - Has anyone used a 'power boost valve' or a rising rate fuel reglator as i know them as?!

Is it worth getting one of these or should I just get another weber adjustable like standard?

Cheers all!

[cuneus]

Weber Alpha

[pwd95]

Got one of these on mine. They suit a flapper more than a Hotwire system. It's running a tad rich mid range but spot on where it counts....full bore in the power band.

I'll be having a session on the rollers sometime to tweak it a bit closer. May even try a proper one on there to see what difference it makes.

[matt-man]

Hi Guys,

thats interesting that there is a mixture of results! I dont want to give myself more problems, but at the same time, would love to get more performance if i am going to change it!

Just to confirm - mine is a flapper....

[Transmitter Man]

Rising rate reg for flapper.

Fixed rate for hotwire or so I've read.

However, I posted a similar question on the TVR Mods forum with this response from Eliot up there in Milton Keynes:

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

Phil
420 SEAC

[ed_crouch]

Matt, the rising rate reg will give you more fuel at all RPMs at high throttle. The problem you have is that it runs out of fuel at high RPMS. Implicitly, though, you probably wont be spending much time at high RPMs unless youve got the boot right in, so more high throttle fuel is a fairly valid solution for lean high RPM running. Fairly.

Like Wyn says, I would suspect it to go a little rich around 3kRPM because the rising rate reg will be giving it more fuel at a time when it doesnt need any more, but as the revs rise through 4.5k I would expect the mixture to come back on spec.

Like I said on the phone, rising rate reg is OK and will probably get you an improvement, but its a slightly clumsy solution.

If I can be of more help (hindrance??) let me know.

Ed.

[rev-erend]

Matt - I have my old regulator sitting on a shelf in the garage .. you are welcome to have it if you want.

I changed it to an adjustable version as I needed to be able to change the pressure.

[matt-man]

rev-erend said:

Matt - I have my old regulator sitting on a shelf in the garage .. you are welcome to have it if you want.

I changed it to an adjustable version as I needed to be able to change the pressure.

Hi Alan,

that would be great! i guess that there is no real way to test the reg? Mine works, but just seems to lose pressure over time...

[TVRleigh_BBWR]

matt-man said:

rev-erend said:

Matt - I have my old regulator sitting on a shelf in the garage .. you are welcome to have it if you want.

I changed it to an adjustable version as I needed to be able to change the pressure.

Hi Alan,

that would be great! i guess that there is no real way to test the reg? Mine works, but just seems to lose pressure over time...

You many want to buy one if these, they seem cheap enough, and should give you a good idea, on fuel pressure. I would not leave it connected but it should give you a good idea, of pressure.

your need to try and borrow or buy a AFR (air fuel ratio gauge) to get a complete picture, or take to a RR.

[rev-erend]

matt-man said:

rev-erend said:

Matt - I have my old regulator sitting on a shelf in the garage .. you are welcome to have it if you want.

I changed it to an adjustable version as I needed to be able to change the pressure.

Hi Alan,

that would be great! i guess that there is no real way to test the reg? Mine works, but just seems to lose pressure over time...

My old regulator was from a hotwire car - not sure if it makes a difference.

I'll dig it out tonight and see if there are any serial numbers on it.

[ed_crouch]

I also have a non-adjustable one if it would help.

Ed.

[Richybaby]

Hi All,

All things being equal, everything set up right, etc, nothinig wrong with the std ones, but I swapped the std one for an FSE RRFPR on my 450SE, flapper, and it was certainly better, got to get them set up right though, not always as simple as it seems, takes a bit of testing, tweaking, testing, etc, but once you got it right they're good. Bigger or higher tuned engines tend to see more noticable results, as you'd expect I suppose.

Cheers,
Rich.

[rev-erend]

That's the beauty of the standard item .. fit it. It works. No messin.

Edited by rev-erend on Wednesday 25th August 22:28

[Transmitter Man]

Matt,

Did you end up fitting the rising rate FPR and if so with what results?

Has the car been on the rollers?

Phil
420 SEAC

[Wedg1e]

My car has the standard 390 type FPR, i.e. an adjustable but non-rising rate type... fuelling is 'close enough' through the rev range according to the BBWF rolling road chaps

ETA: to be fair, my fatter injectors mean I run 1.8 Bar rail pressure.

Edited by Wedg1e on Saturday 18th September 14:41

[dickymint]

Changed to an FSE on me old 350. Worked a treat and solved my problem (or more likely disguised it) .

Bought the pressure guage as well and left it fitted - very useful tool.

[grahamw48]

I had an adjustable one fitted to my Hotwire 400SE in-between sessions on the R/R at the suggestion of the (very experienced) operator, to correct fuelling while setting up.

The car ran beautifully.

It produced about another 5bhp at the wheels too.