GREGGPENN

While I've seen posts about fuel starvation when going around corners too fast, here's my observation.

Recently, I was pulling a WOT run and the [new 383] motor starting cutting out. Caught me by surprise. Wasn't sure it if was missing or what. I noticed it was happening above 4k rpms.

The next day, I called my builder. In his opinion, the only rev limiting problems he could think of were a broken double spring or fueling issue. He voted for the later since he couldn't see my motor having a problem. He was even willing to bet on my doing a scan while running it hard again. So, I did.

He was right, it went super lean above 4k rpms. Then, it snowed and snowed and snowed.

Finally, after waiting several weeks for warm, dry weather I got it out again today. First thing I did was put more fuel in it. (Because I'd read about fuel pump [design?] issues, I wondered about the tank being low. I only had 1/8th of a tank in it because I don't like letting fuel set over the winter.)

After getting it full, I zipped out to the hwy where I thrashed it a bit. Pulls like a banchee well past 5k rpms again.

Note to self: Don't run it WOT (past 4k rpms) when below 1/4 tank of gas.

Weird, huh? FWIW, my IPW shows I'm up in the 85% range when I hit 4k rpms. Because that's the torque peak, I don't go up much past that.

Based on calculations for injector size/PW, it looks like I probably did land in the 350-370hp range like EAPro estimated.

rodj

Not exactly a revelation, GP.

Has been well documented here over the last 10 years that hard acceleration (or cornering) with less than 1/4 tank will result in fuel moving away from the pickup which is why most of us run at least that much in tank at the strip.
http://forums.corvetteforum.com/c4-t...s-out-why.html
http://forums.corvetteforum.com/1553559951-post6.html
http://forums.corvetteforum.com/1566294835-post4.html

383vett

When I was running my 84 on the strip with the stock tank, if the fuel level was nearing 1/2 tank, the motor would burp on launches. It's no wonder at 1/8 tankful the motor was cutting out. Gregg, during the winter, it's best to store the car with the tank full. There is less area in the tank exposed to air which results in condensation. Willie

GREGGPENN

Dang, Rodj. I said I'd noticed the issue around corners....
I just hadn't seen posts about hard acceleration. Even then, mine doesn't crap out until 4k rpms. IOW, I thought my "symptoms" were a bit different.

GREGGPENN

That's more what I would have expected after the (pre-)reading I'd done before this thread. I'm not so sure my issue has to do with something else though. When I drained the 3-yr-old tank before launching the new motor, I saw a marked decrease in fuel "pressure" as it went below 1/8th of a tank. And, that was sitting still, on a stand, in the garage.

To expel the fuel, I disconnected the line at the filter, and jumped the pump relay. I only ran the pump for one minute intervals in case an overheating issue could result.

When I saw how much weaker the fuel pulsed out of the line as the level dropped, I wondered if the pump was failing (another reason I didn't run it for long intervals). Obviously, in this situation, the fuel wasn't riding up the sides like the main theory of other threads.

You're probably right -- especially if Stabil is added. But, I'm never "storing" it for months at a time. At the first sign of warm weather, I always run it on an errand. I also start it in the garage at lease once every couple of weeks.

My habit results from seeing fuel break down in my lawnmower. After one winter, it wouldn't run because of lack of power. Since I don't know whether it's going to be in the garage for a week or a month, I opt for the low-level approach. Plus, I have a heated garage. Not sure how much condensation I'd get in that timeframe (or controlled temp).

93Rubie

Heck, I run a basically full tank at the drag strip. More traction over the rear end. Yes, a little more weight but more traction. No cutting out however.

JackDidley

Me too.

Bensons86

Heck, I didn't think the roads were quite ready for the vette Gregg. Glad you could find some dry ones! I have had nothing but delays with my project. Another winter stuck at the garage...sigh.

But, to add my two cents, I have always understood that condensation was the issue with gas storage, not fuel break down. To that end, it seems that most do recommend a full tank. On another note...must be nice to have a climate controlled garage. Mine is detached.

GREGGPENN

The streets aren't really ready, I am though! There's still water and sand everywhere. It's a traction nightmare for the 383.

Basically, I had to get it out and blow the stink off -- if you know what I mean. 50's all week begs for a few runs around town.

Sorry to hear about your delays. I know trying to finish up in the cold can't be much fun. I'd let it set too -- especially until driving weather comes back our way! We'll have to get together one of these days and check out each other's work!

Chapindad

Greg,

I have had the same problem. I have burnt up a few cheap fuel pumps doing that also. I haven't met a sharp turn that I do not like. I have learned to try and not let the gas drop to low. Centripetal force is a bi***!

sailorsteve

And I would add, use fuel stabilizer when the car will be stored, to prevent "phase separation", aka sludge formation.

Bensons86

I would love to see your work one of these days Gregg. Im afraid mine would be an embarrassment next to yours though.

Im happy though. Will be even happier when its at home in my own bay.

Ill let you know when its ready to role and maybe we can take the wives out for a date or something.

Crepitus

Fuel pickup on my 84 is pathetic below 1/4 tank. How do we fix it. A fuel cell has been in the back of my mind for quite a while. I haven't had the rear body off to figure out how yet.