dowser

David,

I'll have one - but you'll need to add shipping to Switzerland

Cheers
Richard

David_Wallis

You might want to wait for the pictures of the first one yet!

Cheers andy.... Ill check that out...

David

johnfelstead

I was refering more to pats excellent idea as regards muppets, just having a laugh back, dont take it so seriously as it wasnt meant as a moan at you.

The webber adjustable units are great, we use those on the GroupA Escort WRC engine in the rally car and i had one on my westie also. I was explaining how you set the presure with the engine on idle, by disconecting the vacumn hose to give you a static reference point (i.e. atmosphere). As boost increases so does the fuel presure, on boost we see 3.5BAR when this is set to 3 BAR at atmosphere.

I see where you are coming from re maintaining the diferential presure accross the injectors, but in practice that isnt what happens. As an example we run the Rally engine as high as 3.4BAR boost, that would require 6.4BAR fuel presure to stay within your thinking, that isnt what happens. I cant remember the max swing in fuel rail presure we see but if i get time tomorrow i'll check on the pectel datalogger as we are doing the Dukeries rally with the car.

Nope, no problems with the fuel heating up, you are more likely to get heat related issues by installing the swirl pot in the engine bay, which is one reasons why i am going to avoid that solution for now.

The air vents back to the fuel tank via the return from the swirl pot. You should design the swirl pot so the return to the fuel tank is right on top of the swirl pot, at the top of a cone shaped extrusion. Imagine an upside down funel on top of the cylinder that makes up teh body of the swirl pot with a fitting at the pointy bit of the funnel. Sometimes, like on the westie, i couldnt find the space to do that so i had a flat top to the swirl pot, but the return to the tank was the upper most fitting on the side of the swirl pot.

I just ordered the STi assembly, so hopefully i'll be able to give some feedback on that soon. It's not cheep after taxes and shipping etc (similar to the PS mod i would think by the time its here) but it's a nice solution if it works, just a straight swap with the intank pump. I will flow test this so from that should be able to work out the safe BHP levels it could be used for. As it's a genuine STi part that should help keep ffloyd happy with my keeping the car unmodified regime. LOL

R19KET

John,

"As an example we run the Rally engine as high as 3.4BAR boost, that would require 6.4BAR fuel presure to stay within your thinking, that isnt what happens."

I'm afraid I have to agree with Moray here.

RR FPR's are designed to work based on differential pressure, that's why they have an intake manifold input.

If this input is being used, and your NOT seeing fuel pressure at atmosphereic + the boost you run, there is a problem with the fuel system.

However, it's not uncommon for race engines are mapped without the pressure input. This is for safety reasons, so that there is no chance of the hose coming off, and the engine blowing.

I also have to agree with the comments about restrictors in the return pipe. This may well work well on the car you mentioned, but it will be based on a specfic fuel system set up, where no doubt a lot of time and effort has been spent balancing the system. I'd guess that the second pump is also only switched, when the second set of injetors are phased in.

Mark.

johnfelstead

like i say, i'll try and get some data from the pectel. I understand what he is saying re injector rail presure. This is a side issue re the surge problem, but interesting non the less.

As to the restrictor system, i only had the one high presure pump, and the twin high presure pump has both pumps running all the time. You cant switch the second injector rail pump on and off on injector demand, it cant react quickly enough.

Try it if you get time mark, it does work! honest.

R19KET

John,

I would have thought that the second pump could be switched just before the second set of injectors are phased in, as the first pump should be able to maintain puel pressure for all the injectors, assuming they are phased early enough. Usually at circa 6ms.

Tha main concern I have with my fuel system, is that the return ISN'T too restrictive, and ends up increasing the fuel pressure. Another reason why I was mentioning (asking) about phasing the pumps. I may just have the second pump on a dashboard swith, and just use it when needed. God help me if I forget

Mark.

johnfelstead

dont forget, the restrictor is in the return line from the swirl pot to the fuel tank, not the return from the FPR line so the presure in the swirl pot is held by the relatively week lift pump, not the stonking main presure pumps that feed the injectors.

On gareths car the 8 injectors are always running unless it's idleing. Both pumps need to run constantly and i dont like the idea of the pumps being switched on and off, no need, they are there just to provide a presurised fuel supply, the ECU controls when the fuel actually reaches the engine via the injectors.

dowser

John,

I'm interested on feedback of the in-tank item you've ordered.......just had surge on half-tank mark...

Thanks
Richard

johnfelstead

hopefully this will be installed on the car prior to the SIDC day at Dono, that should be a good test of the car.

JohnS

iTrader: (1)

John,

did you order the STI unit thing I mentioned earlier. If so, how did you get on with it, and did it solve the problem.

Lastly, where did you order it form, and how much ?

John

Floyd

iTrader: (9)

JohnF

Your STi kit is acceptable on your STi but I believe you are already on the slippery slope to mod-itis adiction.

There is no cure, even scottish doctors have been known to suffer from it so what hope do you have, eh?

I can just hear you saying down at the rolling road "it's only a small mod, it can't hurt, won't cost much and is handling related - well kind of. Well OK, I do mods occasionally, but I can give up any time, it's just I don't want to right now" LOL



F

johnfelstead

yes, i did install this in my car, and yes, it has cured my surge issues, i can now run it down to 1/5th tank with no problems.

It's way too expansive after import tax and vat and carriage and more friggin tax and yet more frigin tax with bank charges and more friggin tax. You dont want to know how much it cost, lets just say the tax doubled the price and this was doing it all at cost.

Any Subaru Import service company can import this for you from STi