Slalom4me

A thread about "Corner Weights for Auto-X" strayed into discussion
about fuel starvation under cornering. Rather than post off-topic
there, I thought I would comment in a new thread.

Note that members report differing degrees of starvation. The
thread below on sock orientation may explain why.

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What do the rules say about the fuel pickup ?



With the proper selection of materials, the simple solution might
be a little creative plumbing to make better use of centrifugal force.

This leaves the issue of fuel slosh still to be addressed. Perhaps
some fuel cell foam placed into the tank would help. (Edit: foam
would interfere with the operation of the float for the OEM fuel gauge.
Mr6sp first brought the idea of foam to my attention & Zix mentioned
that motorcycle racers use foam with good results.)

Here are some other threads about fuel slosh and possible solutions.Edit: Several simple suggestions were put forward in the threads above. I've
been following the recommendation to keep the tank full for now but I have a
replacement sock and gasket to install.

Before getting caught up in building a fancy pickup, I'll install the new sock in
the preferred direction, make sure it is fitting into the yellow baffle and check
that the tube to the pump is shaped to place the sock as low in the tank
as possible.

Ken R.

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Vetracr

Near as I could tell the SCCA rules don't say anything about the fuel pickup. Your dual pick up MIGHT work. I think the idea you propose would still allow the pump to suck air and starve from pick up opposite to the G forces.

Its been awhile since I've been in the fuel tank of a C4 but another option would be build a simple rectangular cover to go over the existing fuel pump tray. Leave a 1/4" gap between the bottom of the cover and the tank floor. Leave a similar gap between the cover and the pump. The cover will trap the gas from sloshing away from the pump tray under G loads. I made a powerpoint sketch but I can't figure how to insert it.

Larry

ZR1 MK

Use fuel cell foam and a pickup pan. If you dont mind using an aftermarket fuel gage, you can get a tube type sending unit and pack the tank better and its much easier. Aftermarket gauges arent compatible with the stock gauge due to different ohm requirements.
I have a ZR1 and therefore dont have a starvation problem, but use the foam to keep fuel weight transfer down.

Slalom4me

Vetracr - is it that you feel that the pump would
pull enough vacuum to counter centrifugal load on
the ball? I think that using a weighty-enough single
ball or possibly multiple ***** might serve well.

The issue I anticipate is that without some thought,
the ball will block the outlet to the fuel pump.
I have some ideas for the design of the ball tube
and for the hose runs & left/right pickups to be
able to fit the package in through the existing
opening if anyone cares about discussing it here further.

In any event, if anyone decides to play with this
approach, drop me a line to let me know how you tackle
it and what the results are.

ZR1_MK - thanks for bring up the foam and tube-type
float. You prompted me to go look up the OEM gauge
requirements and I found these to be 0-90 ohms for
the '89 C4. 0-90 is a common value over quite a wide
range of GM vehicles.



After looking for a while, I found that JAZ, the fuel
cell people, offer at least two non-swing arm 0-90 ohm
sending units. They comment that these are suitable
for use with fuel cell foam. Online price is well under $100.
It looks a bit bulky. Do you know of any other floatless
senders to take a look at?

Thanks for the tips.
Ken R.

.

ZR1 MK

It was many years ago, but at the time, I didnt find any sending units in the stock ohm value. Maybe they werent available or I didnt look good enough. The units I found where a tube about a 1/2" diameter in a variety of lengths that could be trimmed to fit a particular application. Problem was the ohm value. It was different from stock and required a seperate gauge. I didnt go that route because I didnt want the extra gauge. I dont recall the brand etc.

Slalom4me

Hope my remarks were not taken as criticisms.

I didn't even know such level sensors were available
until learning about them from posts by Mr6spd (earlier
thread) and again here from you. It was your post that
prompted me to look into the fuel gauge ohm ratings for
my vehicle and search to see what was available currently.

With new products coming out all the time and more
information going up on the web every day, finding what
we actually want keeps getting easier. But I know from
personal experience that it wasn't always this way.

For any one interested - the three common ohm ranges
appear to be:I came across Stewart Warner units but these are 240-33 ohm.

Fuel Safe shows three possibilities. A sensor for a gauge, one
for a 'low level' indicator light and the one I hadn't considered
- a manual fuel level dipstick. See page 16 of 17 in their RR catalog
They do not mention ohm ratings except to say 'Specify Ohm
range of fuel gauge to be used'.

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ZR1 MK

Not at all.
So what are your plans after your research?

Slalom4me

Still the same for the immediate future.

I've had a new sock since last fall. Some unscheduled
other work has interfered but I am going to install this
for now. I'll align it in the recommended direction,
make sure it is positioned as well as possible and take
photos/measurements while I have the assembly out of the
tank.

If this works with low fuel, I'm done. If not, I'll raise
the fuel level for the rest of the season and perhaps pull
out the ideas in these threads for a winter project.

Thanks.

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