Hi guys, hopefully someone can help me out with a issue I had today.

I was on track this afternoon at Kames and after a while I think my car was suffering with fuel starvation on or just after a hard left hand corner. It happened after the same corner each time. The fuel light on my r1 clocks had only just came on (this normally means I've got about 100miles left before empty). I put 5 litres into the car from one of my spare fuel cans and it still suffered with the same problem so I then stuck my other 5 litres of fuel in and this seemed to resolve the issue.

My question is surely with the 100 miles worth of fuel and one of the 5 litre cans added to it, I shouldn't have been suffering with fuel surge? I was cornering really hard but surely the amount of fuel left in the tank would be enough to prevent that from happening?

Without adding anymore fuel I drove the car the 50 miles home and gave it a bit of stick, but wasn't as hard as being on track, and couldn't replicate the fault, despite it doing it again on my last time on track before leaving.

Does anyone know if the standard MNR tank is baffled, and if not, would having it baffled stop any fuel surge issues?

Or am I barking up the wrong tree and the fault is something totally different??


Cheers for any help....

Hi

A couple of assumptions here.. BEC? Fuel Injected? plumbing is: - Tank> Fuel Pump> Fuel Rail?

If so it's entirely possible, in fact quite probable if the tank's not baffled and I'm afraid I can't help you on that question.

You would be amazed how much fuel moves around, I've had the same issue myself with a tank and that was literally the dimensions of an old tin type 5L oil can (i.e vertically installed & very small..) ended up with Anti Surge Foam and running over half full to temporarily fix it!

Assuming the tank isn't baffled and you don't want to be taking the tank out until the deep winter to fix it properly, the above mentioned foam from somebidy like Merlin Motorsport etc can be simply squeezed into a small ball and inserted into the tank via the filler neck, but even with that you'll be looking at running a fair bit of fuel as it will help but it won't cure.

HTH

I know the tank i got from MNR deffo wasnt baffled because i had to have it modified to take the R1 fuel pump and i had the fabricator fit a baffle plate at the same time.

When i got my MNR built they asked me if i wanted the tank baffling, or foam filling, so unless you stated you wanted it, then it probably isn't.

There is a small sump on the bottom of my tank with the fuel exiting towards the left that is meant to help with fuel surge, i presume they do as standard?

I do still get fuel surge though, when i'm on Blyton Park circuit exiting "The Ump" with my foot flat to the floor accelerating hard around "Lancaster" which is a left hard bend, the car feels like it holds back a little until the track straightens out, then you can feel the power fully come back, so i need to sort something out to prevent this.

[Edited on 21/8/13 by Davey D]

Hi, sorry should have replied to this sooner.

My car runs a 2003 fuel injected r1 engine and the plumbing is tank to fuel pump to fuel rail.

I've got the small sump under the passenger side of the fuel tank and that is where my fuel line runs from. Davey what you are describing is exactly the symptoms I was experiencing.

I only p,an on doing 1 or at most 2 more track days before taking the car off the road for the winter so will live with the fault till then.

What's the best solution to resolve this, a new tank with baffles and a smaller hole feeding into the sump in the passenger side of tank, or can my own tank be modified?

One quick and dirty partial fix that might help top some degree is to tilt the tank towards the outlet.
Over the winter I would fit baffle foam if you don't already have it

On my racers we always built the car with the tank outlet at the rear so fuel was always available under acceleration, but that was easiest way as the engine was at the back.

Link to Baffle Foam on Ebay

How quickly does fuel flow through the foam? My idea is to cut off the top of fuel tank, weld in a baffle plate that will also serve to locate the foam and then place the foam over the outlet so there will always be fuel at the outlet. I'm just concerned that the fuel won't flow through the foam fast enough?

I don't want to just poke the foam through the filter hole as no doubt it will end up getting caught up with the fuel gauge float.

In the past I have baffled the tank but also put the fuel return into the small sump on the bottom of the tank,

This then helped a lot and no fuel surge as I think it used the fuel pumped back when it was getting low on hard cornering,

Only my thoughts some people say this is ot correct, but I think mnr put there fuel return ar the top of the tank?

Cheers

quote:

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Originally posted by Davey D
How quickly does fuel flow through the foam? My idea is to cut off the top of fuel tank, weld in a baffle plate that will also serve to locate the foam and then place the foam over the outlet so there will always be fuel at the outlet. I'm just concerned that the fuel won't flow through the foam fast enough?

I don't want to just poke the foam through the filter hole as no doubt it will end up getting caught up with the fuel gauge float.

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Hi

Don't know what an MNR tank looks like, but several of you have mentioned a 'small sump'..

On the old Mini Van style fuel tanks (i.e. long and thin, cross chassis installation) which were prone to surge the mod used to be a sump a good few inch's a side - perhaps this is worth looking at?
Plus baffles of course.

HTH

Had the same problem, solved it with a swirl pot

http://www.rallydesign.co.uk/index.php?cPath=1578_1586

PWL

[Edited on 24/8/13 by pwl]

Hi pwl, do you have any pics of your setup with the swirl pot?

I am sorry I have no pic.

I have the swirl pot on top of the fuel tank.

The system is build like this:



PWL

I have an unbaffled, not-foam-filled tank with a pump at each end (T'd together), and this works very well, I don't get any fuel starvation on track until the tank is very nearly dry.

I suffered with fuel starvation in my race car when I first started, and that was with a std MNR foam filled tank. the solution was a swirl pot mounted above the tank, fed with a lifter pump. I've had no problems now, in 3 seasons.

quote:

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Originally posted by amalyos
I suffered with fuel starvation in my race car when I first started, and that was with a std MNR foam filled tank. the solution was a swirl pot mounted above the tank, fed with a lifter pump. I've had no problems now, in 3 seasons.

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