My85

I've heard it different ways from different people - some say the full tank keeps the weight more evenly distributed in the rear end but I thought weight was your enemy ? So help needed from the pros-- Whats it goin to be - If I let it get to a qtr I get fuel starvation on left had sweepers so i'm not letting it go that low-
TIA.
Ron

RX7 KLR

Full. The car sill starve at 1/2 tank on sticky tires. If you are worried about weight pull your spare.

CHJ In Virginia

I run with a full tank. It keeps the weight distribution closer to even. On all but the fastest courses the 60 lbs of gas will not make a difference.

VettesRule

Between 1/4 and 1/2.

vettmike

Always full, most C4's will starve in the corneres with less than
a 1/2 full tank.

We never let our '89 get under 2 bars from full, the car is more balanced
and was setup with the tank full.

MSR

i was appalled when i first bought my car, in terms of fuel level vs starvation. i can't believe gm would make a performance car that needs to lug around half a tank of dead weight just to keep from starving while cornering.

has anyone discovered a fix for this? (besides a fuel cell.)

thanks.

Red5

I found a cure..... i switched to a carb. :yesnod: For some reason I dont get the fuel starvation anymore.

So in absense of fear of fuel starvation, would it be better to run with a 1/4 tank or a full tank?

Goody

I had a smidge over half tank and was in a long fast left hander and went into starvation mode.....at least it saved my brakes a bit :crazy: I now fill up the night before or morning of. :seeya

Bill Dearborn

Never had a fuel starvation problem with my 86 unless the gauge was very low. The reason I chose to run a full tank most of the time was that it reduced fuel slosh. With a half tank there is a lot of room for the fuel to move back and forth and build up momentum before it hits the side of the tank. With a full tank it doesn't move around as much and doesn't provide unwanted sideways thrust. This little bit of alternating sideways thrust could be just what you don't want when going through a slalom. Think of it as a slide hammer going back and forth across the back of the car. The C5 two tank system with the tanks in front of the rear wheels reduces this problem since the tanks are more vertical than horizontal and the slosh is reduced and the placement of the tanks reduces the affect of any slosh.
Bill

MSR

bill, do you think the early C4 tank might be different? i'd convert if it meant i could use the last 10 gallons in auto-xing or open tracking...

Bill Dearborn

I think they are all the same. They are flat and wide. Like I said I never had a fuel starvation problem. At one DE at Pocono I put 16 gallons of gas in at one time late in the day. Another time at Watkins Glen during the last session of an event I went out with less than a quarter tank and after two and half laps realized I had enough gas to get into the pits if I put it in 4th over drive and loafed along at 60. When I got back I had just enough gas to get on the trailer.
Bill

RX7 KLR

"Never had a fuel starvation problem with my 86 unless the gauge was very low."
No flame here, however I am going to guess you might be racing on street tires, not using 100% of your car or are running open track rather than solo2. In both my past 86's and my current 89' I could run low, around 1/2, for open track but with the tight solo2 stuff the car WILL starve at 1/2. You are right about the slosh, full is better than part full. You C5 guys do not have this issue at all so your fuel levels do not apply to his question.

My85

Bill,
correct me if I'm wrong but ran your 86 to National SOLO 2 Titles didn't you. Was it SCCA or another Organization? If you say it about Solo 2 I believe It. Thanks for weighing in on this for me.
It was an Auto also wasn't it? I Think I'll go with a full tank because I can't gestimate very well. I had the same problem this sunday coming out of a left sweeper acellerating hard and the car just pauses for about 1 or 2 seconds the takes off. I started with a qtr of tank and the problem didn't show up until the third run. I will drop the Spare out and keep the tank full.
Thanks for all the help guys.
I'm heading for Atwater on the 4th and 5th to do the SCCA 2 day event there should be fun.
Thanks Again--
Ron

kkonen

I heard something one time about a Z51 tank having baffles in it. Does anyone know if there is any truth to this? My 95 cuts out with well over 1/2 tank remaining. I now run with as full a tank as possible.

RX7 KLR

I have had three Z51 and one FX3 car and had the pleasure of doing fuel pumps in three of them, none had baffles. The owners manual does say the Auto cars have an 18 gal tank and the Man a 20 but I could not see a difference on the inside of either.
1LE fbodys are supposed to have a baffled tank but I have never seen inside one.

MSR

ya, i can starve mine of fuel with 1/3 tank, on the street, on street tires. with less than a 1/4 tank i can starve the car hard enough to kill the engine, needing a crank to get it going again.

given that, i've never even tried auto-xing it with less than a full tank. i dunno if mine is below par, but if this is the norm, gm should be ashamed of themselves. i could literally run my mustang out of gas while auto-xing it!

unfortunately, my camaro is almost as bad as the vette. but i can get through an auto-x on race tires with 1/2 tank in the camaro, even with 2 drivers.

on the other hand, how did all of the vette challenge roadracers do it back in the '80s? i can't believe someone didn't figure out a fix...

Rob 93ZR-1

I run a full tank as well. Anything below 1/2 tank and it starves. I would rather have a little extra weight than have fuel slosh over when I'm running on the ragged edge of adhesion.

Bill Dearborn

My autocross experience has been here in the Northeast. Some parking lot courses but mostly Go Kart Tracks and some events at Griffiths Air Force Base in Rome, NY. Most straights were no more than 250 ft long with hair pins and tight slaloms right after the straight.
Bill