Following various discussions today (thanks mellow, Harvey and eveyone else who tried to help), it would appear that my 96 STi Type R/A is suffering from fuel starvation from time to time.

This became obvious at Croft today when, if I took the hairpin at any more than a snails pace, I'd have a horrendous misfire all up the main straight. If I take the hairpin really slowly then its fine.

Obviously I need to sort this PDQ so does anyone have any similar experiences or advice to offer?

cheers,
simon

 

If its starving then the logic would suggest an uprated Fuel Pump. Try this as a search as im sure someone was getting these for people.

 

Keep the fuel level high on track or fit a swirl pot. A fuel pump will not help.

 

It started happening with fuel at approx 3/4 full, filled up again just to eliminate this.

Will try the swirl pot if you think it will help.

thanks,
simon

 

This from Powerstation: http://www.powerstation.org.uk/News_Page.html

Description The Subaru Impreza suffers badly from fuel surge when the fuel level drops below 1/4 tank. This can cause misfires or even the complete destruction of the engine if the car is being used hard. Powerstation have addressed this by producing a high pressure fuel pump and swirlpot kit. The standard intank pump acts as a lift pump feeding fuel into the swirl pot which inturn feeds ,surge free, fuel to the high pressure pump. This neat combined tank and pump fits on the front bulkhead and l/h chassis rail. We have tested this unit on our STI3 at Donington Park and 1.28 second laps with the tank on empty!!!!!
Specification Swirl Pot
High Pressure Pump
Wiring Harness
Unions
Hoses
Hose Clips
Price £350.00 + VAT
Picture:
Swirl Pot
and Pump



There have been other threads on this - I gather there is also an STi item and some have built their own. For a major track car with big issues it is probably worth all the hassle.

I had fuel surge at 3/4 tank on track but that was because a new fuel pump had a smaller pickup.

 

Before you start spending money on a swirl pot or uprated pump it would be advisable to confirm what the problem is. From your description today it seems most likely to be a lack of fuel but that could be caused by one of many things or even a combination of several. Unlikely, but when was your fuel filter last changed.
A fuel pressure guage would help, even if installed temporarily. Almost any pressure guage will do the job as long as it reads to around 5bar/75psi. I have seen some 100psi guages for fuel and they are quite cheap. Uprated fuel pumps are available from Mark Aigan at very reasonable price, around £130, but that will not necessarily be a fix until the actual root cause is found.
If you want to talk it through further mail your phone number to me per my profile.

 

Thanks for taking the time to post guys, will be removing induction kit and dump valve tomorrow morning to remove these from the equation.

The car had a new fuel filter on Friday so unlikely to be this, although someone (i forget who) did commented on the 'non-standard' fuel filter.

Checking the fuel pressure seems like a decent staring point, although I've never had it happen before, and it didn't happen anywhere other than that tight hairpin at Croft so not sure how easily i'll be able to re-create the circumstances.

cheers,
simon

 

Does the fuel pick up sit in the bottom of the tank or is it elevated?

 

No idea- will check tomorrow