I have got a bit low on petrol, but just as the light was going on at 8 litres left when I went over big bumps/undulations there was a feeling like fuel starvation you get on track, but this was in a straight line, and a grinding noise from the fuel pump. Any thoughts - except go and fill up! But at 8 litres I never had issues before.

 

cr@p swished up from bottom of tank and clogging something?

 

I thought this was a trackday only phenomena on hard corners, but this was even doing it in a straight line on full boost. I gather from someone in the know that this is relatively common as the torque is increased on a car. It must be quite difficult for a small amount of fuel to stay in the right bit of the tank when forced backwards by acceleration or moved by cornering. I know what it is now and can work around it - don't go under 1/4 a tank.

It is fine now I have filled up again. With an uprated fuel pump there is a little more audible minor grinding noise which is quite handy to alert you to fill up apparently.

Interesting that it never did it in a straight line to the limits of the original turbo.

 

I've only ever experienced surging when the fuel's been very low. Never heard the pump making any noises. That's even before putting over 57 litres back in the tank

Were you giving it some stick over those bumps @ the time?

Stefan

 

Experimenting with my favourite off camber corner off a roundabout with a crest in the middle of it where you normally lose traction momentarily. This was with 8 litres, but with only 3-5 litres left in the tank was doing it in a smooth straight line intermittently if you gave it enough welly.

 

John, you could have the pump pick up in an elevated position, am due to change mine over the next couple of days to the same pump you have so will let you know if I spot anything as I do it. (my original is short on pressure by nearly a bar at full boost, its a bit tired)

 

Thanks Bob - I had it pushed down into its seat as far as I could, and the filter sock seemed to be almost as big as the old one. Interestingly the filter end is rotated 180 degrees relative to the outlet end compared to the original pump, so I required to bend the outlet pipe slightly. I gather the STi pump is different again.

 

John

Did you notice any increase in O2 voltage with the uprated pump at high rpm's ?

 

To be honest I have not logged it in detail yet, just checked it was ballpark. Start up is better, throttle snap crisper. I just wanted a reliable base on which to map it, with plenty of reserve of fuel pressure, especially as I will be flowing considerably more air as I tweak it all progressively, now I am not scared of intake temps in the 40s

 

I don't know Intake temps in the 40's, 1.5 bar boost, you're becoming.........well.........errr a NUTTER

 

Cosie, this question I can answer first hand... when we fitted the uprated fuel pump to my car, the O2 values didn't change all that much in mid rpm/mid load situations, but they changed *drastically* at high rpm/load situations. We need to change the map in that area by about 10 % in some places Knowing that these pumps loose pressure as flow goes up, it made sense, and was exactly what we expected (though we were surprised by how much difference it actually made).

John, not much use probably, but did you consider fitting a swirl pot ?

 

What may I ask is a swirl pot?

John the clueless

Oh, BTW don't overtighten the 8mm nuts when refitting the lid back on. Don't ask for details it is embarrassing I never was any good with a spanner

 

John, see

Powerstation are probably not the only ones doing them, but there is some explanation on their news page.

It's basically an extra pump with a "container" that fits under the car at the front. That container makes sure there is always enough fuel available (fuel can't escape once it is in it).

Don't have it on my car, but I've heard from a few people that it indeed solves the fuel starvation issue. Depends on how big the problem is perceived I think, I just fill up more often.

 

not keen on the powerstation surge tank/swirl pot design at all.

Looks far too fussy, and over complicated.

 

I Was thinking about making one of these but figured it would be expensive as I would have to have two uprated fuel pumps... unless you can use the standard one to supply that???

David

 

I thought about a swirl pot but when i weighed all the parts, pump, fittings, tank, mounts, hoses, wiring.... I was better off weight wise just running 6 litres more fuel in the tank !!

The reason I ask about the high rpm O2 is that I done a similar mod and the extra fuel injected due to the increased pressure at the top end killed off 25 bhp !!! The original Subaru mapping seems to have compensated for the OE pumps shortcomings.

It's just that JB's car is on the rollers this weekend for a before/after TEK3. The 'before' may look rather flat with the uprated pump, this may mask the performance increase due to 'other' modifications ?..... all IMHO

 

Good thought. I'll measure some fuelling tonight and compare it with the earlier logs.

 

how much and where would I get my hands on an uprated pump? is the the sti jobbie thats available thru GGR?

Cheers
Fergal

 

Try Mark - R19KET He had some recently and has supplied a few people on this forum

 

I have also just changed my fuel pump - the car is running a little better

Today I had fuel surge in a straight line on just less than a third of a tank! However I put this down to the hugely increased torque as the pick up is in the same place as the old pump.

Can't explain your issue John.

Trout

 

This was the first tank after the new turbo went on so that must be the reason.

 

John,

now that makes a lot of sense - I hear you are very pleased

Trout

 

Pleased? I am flipping ecstatic

 

I uprgraded the pump on MY98 Terzo and found the original sock needed to be modified to fit the new pump as the one that came with the new pump sat to high in the tank.

 

John, installed my pump today, install easy and straightforward, Pump fitted into the same position with the filter in the same orientation as oem, my tank has a "bucket" into which the pump fits to minimise surge, did you notice that in your tank? Connections straightforward, just used in line crimp's to connect the pump wiring. Kit contained all necessary for a direct replacement. Significant improvement given my oem pump was failing, now have a very flat map with extremely consistent fueling across the range. Injector duty in the low 60's at full boost and max revs. All in all a very good result. Interestingly cruise fueling was only marginally out. This using stock fuel pressure.

 

Bob I unfortunately did it in semi darkness, so did not see a bucket, but might take a look - it was quite a bit of a squeeze to get the assembly back into the tank.

 

Bob, John,

I assume your pumps had the pick-up and output line in the same place as the OEM pump?

I got an uprated one recently and the top and bottom are rotated by 180Deg to each other. So to fit the rubber boot and sock correctly, the output line and electrical conector are the other way up from the OEM one???? I assume the new pump has been mis-built?

 

James I had the same 180 degree issue, but it just meant bending the line that goes to the pump outlet, the pickup and sock filter sit the same as far as I could see.

 

Ah-ha - I had assumed the pump was a misbuild. Didn`t want to hack it about without checking. Surley it would be easier if the pumps where `correct`. You also stress the electrical conection a bit more as you have to `stretch` the lead (and its in the `wrong` place when fitted...........)

Bob - same issue with yours?

 

The wiring didn't seem stretched I just looked at it for a while working out how to fit it and then noticed the rotation - of course you tend to secure it at the outlet first and follow the pattern on the old one and then the seat/inlet does not fit.

There is a new hissing noise to get used to as well (not a leak). But it does the job nicely.

[Edited by john banks - 5/13/2002 11:27:26 AM]