Autocross Experiment

14BlackCherry · 09-19-2016, 07:38 PM

So yesterday I decided to run with the lowest fuel level just to see if fuel starvation would kick in. Our fellow member "Brendan" was there to witness this. I'm wondering if design changes in the '13+ models were revised. We got 6 runs yesterday here's the picture just before my 6th run:

Here is the YouTube video. The 6th run would've been my fastest except for the cone I murdered. I would of won STR by 1 full second. Also in the slalom the car is on the rev limiter, my tires are 255/45/18 (RE-71R) which explains the lower gearing.

No fuel starvation experienced. Just thought I would share I know others experiences are different, and thus maybe why they're experiencing starvation.

Brendan · 09-19-2016, 07:42 PM

It's either one of two things; the fuel pump issue was fixed as one of the changes in the 13+ models, or autocross on street tires doesn't see high enough sustained g's to cause the issue.

gomer_110 · 09-19-2016, 08:18 PM

Quote:

Originally Posted by Brendan

It's either one of two things; the fuel pump issue was fixed as one of the changes in the 13+ models, or autocross on street tires doesn't see high enough sustained g's to cause the issue.

My money's on the second one. If there were 315 Hoosiers on the car it might be a little different. The skinny 'stones just aren't enough tire to create enough lateral g's.

zpower86 · 09-19-2016, 09:46 PM

I have never had fuel starvation when I've run between 20-30% fuel level, EXCEPT ONCE recently at a pro-solo. It happened at tail end of a LONG, fast right hander. Fuel level was about 30% or 3-4 dots. This was in Blytheville on high grip concrete on RE71s, 275/35R18 square. My Z is a 2011.

PS- I would check the level via obd-2. I've seen the indicator and obd2 out of sync after a refuel when I know the amount of fuel I put in.

cjwsrt6 · 09-19-2016, 11:30 PM

The only time I get it on street tires is wide right hand turns, which you had a couple of, not sure how you got away with it. I can't run any lower then 3/4 tank without having issues

Brendan · 09-20-2016, 12:39 AM

Ive also run low for as long as I have had my car with no issue.

Sent from my VS980 4G using Tapatalk

2011 Nismo#91 · 09-20-2016, 09:02 AM

Fuel Starve doesn't happen on short right hand turns no matter how hard you do it because there is still enough fuel in the pump to keep it primed and running when the fuel splashes back a few seconds later. But when you take a long right hand high g turn for like turn 9 here (~10sec @ ~70mph) you will starve. There is nothing special with the 13+ fuel tank and pump design that would stop fuel starve.

Brendan · 09-20-2016, 09:57 PM

So in conclusion we can say that if a car is prepped up to str and you primarily autocross, you'll be okay.

09-19-2016, 07:38 PM	#1 (permalink)
14BlackCherry Base Member Join Date: Jun 2014 Location: Colorado Age: 37 Posts: 178 Drives: 14 Nissan 370z BC M6 Rep Power: 11	Autocross Experiment So yesterday I decided to run with the lowest fuel level just to see if fuel starvation would kick in. Our fellow member "Brendan" was there to witness this. I'm wondering if design changes in the '13+ models were revised. We got 6 runs yesterday here's the picture just before my 6th run: Here is the YouTube video. The 6th run would've been my fastest except for the cone I murdered. I would of won STR by 1 full second. Also in the slalom the car is on the rev limiter, my tires are 255/45/18 (RE-71R) which explains the lower gearing. No fuel starvation experienced. Just thought I would share I know others experiences are different, and thus maybe why they're experiencing starvation.

09-19-2016, 07:42 PM	#2 (permalink)
Brendan Track Member Join Date: Apr 2013 Location: Colorado Posts: 642 Drives: Poor man's Porsche Rep Power: 542	It's either one of two things; the fuel pump issue was fixed as one of the changes in the 13+ models, or autocross on street tires doesn't see high enough sustained g's to cause the issue. 14BlackCherry likes this.

09-19-2016, 09:46 PM	#4 (permalink)
zpower86 Premium Member Join Date: Jul 2011 Location: Huntsville, AL Posts: 189 Drives: 2011 Nissan 370Z Rep Power: 14	Autocross Experiment I have never had fuel starvation when I've run between 20-30% fuel level, EXCEPT ONCE recently at a pro-solo. It happened at tail end of a LONG, fast right hander. Fuel level was about 30% or 3-4 dots. This was in Blytheville on high grip concrete on RE71s, 275/35R18 square. My Z is a 2011. PS- I would check the level via obd-2. I've seen the indicator and obd2 out of sync after a refuel when I know the amount of fuel I put in. __________________ Charles K 2011 Nissan 370Z, Black, 7BS youtube.com/rotarypower86

09-20-2016, 09:02 AM	#7 (permalink)
2011 Nismo#91 A True Z Fanatic Join Date: Mar 2011 Location: NJ Posts: 2,402 Drives: slowly Rep Power: 40569	Fuel Starve doesn't happen on short right hand turns no matter how hard you do it because there is still enough fuel in the pump to keep it primed and running when the fuel splashes back a few seconds later. But when you take a long right hand high g turn for like turn 9 here (~10sec @ ~70mph) you will starve. There is nothing special with the 13+ fuel tank and pump design that would stop fuel starve. zpower86, gomer_110, Hotrodz and 3 others like this. Last edited by 2011 Nismo#91; 09-20-2016 at 09:04 AM.

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09-19-2016, 11:30 PM	#5 (permalink)
cjwsrt6 Enthusiast Member Join Date: Apr 2014 Location: Alabama Posts: 452 Drives: 2005 crossfire Srt6 Rep Power: 11	The only time I get it on street tires is wide right hand turns, which you had a couple of, not sure how you got away with it. I can't run any lower then 3/4 tank without having issues

09-20-2016, 12:39 AM	#6 (permalink)
Brendan Track Member Join Date: Apr 2013 Location: Colorado Posts: 642 Drives: Poor man's Porsche Rep Power: 542	Ive also run low for as long as I have had my car with no issue. Sent from my VS980 4G using Tapatalk

09-20-2016, 09:57 PM	#8 (permalink)
Brendan Track Member Join Date: Apr 2013 Location: Colorado Posts: 642 Drives: Poor man's Porsche Rep Power: 542	So in conclusion we can say that if a car is prepped up to str and you primarily autocross, you'll be okay.