Do our 1st half 4th Gens have problem with fuel starvation on a hard left hand turn?

I ran a road race course today and on hard right hand turns the engine would almost die. Then when I straightened up full power came back.

 

How full was the tank? Stock fuel pump sending unit?

 

It is a potential. Have you modified your fuel pump? The stock unit fills the fuel bucket from the tank, then feeds the car from the bucket.

 

I've put in a pump w kit from Racetronix so hopefully I've got the fuel pump cover. I only had about 5 gallons in the tank.

 

The Racetronix kits include the venturi pump so that should have should have kept fuel in the bucket over the turns. Another option to look at is hydromat from Holley, but if the bucket was ran dry, it wouldn't really help. 30# injectors are pretty small to have cleared the bucket, so I am wondering it you could potentially have a leak that allowed fuel to escape the bucket in the turns?

 

I'm gonna need to pull the pump assembly and check it. (Thank goodness for the trap door) I had some trouble working the assembly into the tank so I worry I may have dislodged something. Hard for me to imagine a hole leaking enough to deplete the bucket that quickly but all things are possible.

A related question for you sages.

When I got to the track I was lower on fuel than I realized, so I bought gas there...racing gas by VP Racing. They had three available with only the names of 110, 100, and 95. First are those octane numbers or do they represent something else? I put in four gallons of 110 as it was the least expensive at $8.50/gallon. Did I put something in my car it may not have liked running? I wish I'd known my track time was delayed half an hour, I'd have gone to the local gas station and paid $2.50/gallon.

 

I’m interested if anyone else knows. I would also think those numbers were octane. Potential issues could be caused by leaded gas or e85 if the fuel system wasn’t made for it.

 

Yeah what I'm wondering. Since I don't have catalytic converters, would leaded gas cause any other problems? I'm sure an increased alcohol content would be a problem.

As soon as I was finished I went and filled the tank with premium fuel.

 

Here's what I found on VP Racing's web site:

Antiknock octane: 110. Features: VP-110 has the highest Motor Octane (MON) rating of any 110 fuel on the market at 107. It is formulated for use in all naturally aspirated engines with compression ratios of up to 13:1. Bottom line: VP-110 is a good, all-around fuel for hopped-up two-stroke engines.

From another website:Usage: A high-octane, leaded, non-oxygenated fuel that bridges the gap between pump gas and C12 for use in stock or modded two-strokes.

Preferred engine type: Two-stroke.

Antiknock octane: 110.

Features: VP-110 has the highest Motor Octane (MON) rating of any 110 fuel on the market at 107. It is formulated for use in all naturally aspirated engines with compression ratios of up to 13:1.


VP 100 Professional grade 100 octane unleaded blend for all forms of motorsports. Spec fuel for IMSA sports car racing in North America.

Haven't found anything on 95 but reading the description above 110 is probably not what I should have bought.

 

Running unleaded 110 will not harm anything. Won’t help either, unless your dynamic compression ratio is too high, you are running forced induction, or nitrous, or you are experiencing detonation.. It will help with power adders, but only if it is specifically tuned for that octane. Each fuel also has a slightly different specific gravity and energy content (BTU/#). The combination of the two yields the specific energy content, and the higher that number, the more power it will make. Not a lot, but with my engine tuned for Sunoco 94 normally aspirated, simply replacing that with VP C116 picked up 6 HP, because of the higher specific gravity. We ran that on the dyno to baseline the engine without nitrous, so we could get a true measure of the nitrous HP increase.

Not sure what the significance of the term “two stroke” is with reference to the 110. Sounds like it’s for go karts.

There should be a detailed spec sheet on the VP website with all the info on octane (motor and research), specific gravity, lead content (if any), oxygenate content (if any), etc.

Running leaded fuel will gradually destroy the O2 sensors. That is true even for wide-band sensors.

Ethanol has a different stoichiometric ratio than gasoline, so the more ethanol the greater the error in the A/F ratio control system, based on O2 sensor readings.

When you installed the Racetronix pump, did it require you to reglue the bucket? Could that have failed, allowing the bucket to empty? I'm sure you are aware of the innate error in the 4th Gen fuel level readings. Based on SHOEBOX’S calibration, and my own attempts to develop a true number of gallons remaining vs. gauge reading, when the gauge indicates 1/2-full, you only have 4 to 5 gallons left.

 

Yes, I was to glue the basket pieces together so certainly that could have failed. I'll be pulling the pump to check it.

Yes, while I don't recall seeing that specific info on the fuel level sender, I am aware of it's inconsistency and that when the Camaro's gauge reads empty it is truly empty.

Glad to get the information regarding the fuels. It's not anything I have ever used before and may never use again since I'm not into competition racing but it's good to know.

 

4th Gen LT1 F-body Tech Articles

 

Finally found time to check the fuel pump. The fuel basket was securely in place. The only thing I saw was the return line, inside the tank, was off the hardline that exits the fuel pump assembly. However, it's possible I did that while removing the fuel pump assembly from the tank. Regardless the return hose was a little short so I replaced it with one an inch or so longer and put a spring clip on it to help make sure it doesn't come loose.

Not sure that return line being off would cause my problem. I probably was too low on fuel. I'll be returning to the track later this summer and so can see if a full tank fixes the starvation. I also hope to get a dyno test soon to see if the Racetronix kit helps my top end.

In the meantime I installed a fuel pressure gauge and have it feeding data to my HPTuners which will let me chart fuel flow all the time but primarily for hard acceleration, high rpm conditions.