Left Hand turn fuel starvation on WOT

[Huehuecoyotl]

I'm getting what feels like hiccup fuel starvation in/just after fast left hand turns followed by WOT, like 110 degree corners right after a sweeper into a straight, never when on a full tank, but consistently at 3/4 tank and below. Wondering if anyone else is having this. I dont recall it being NA, so I will be asking folks who track that go FI, cant replicate on the street, just not the same traction as rcomps on a track. LMK. I have this on two different tracks different fuel sources. Can make it happen on a cold pump.

I'm FI at 10psi on OE fuel system. I know folks will say go to higher output pump, but not sure thats diagnosing problem.
Oil temps were high both full tank and not full tank, both times it happened. Went to gas station filled up car with car and oil way hot, and no issues, so its not an hot oil temp driven event

Can not replicate with street tires
Must have R-comps, must be driving at 10/10s

WOT thru sweeper --->STAND ON BRAKES--->downshift--->Turn FEVERISHLY(feathering throttle to rotate rear end at break neck speed) --->then milliseconds right after apex go full WOT and go wide onto a straightway(INSERT hiccup)WOT at top of 2nd gear,sometimes event at beginning of 3rd, then this straight goes to 4th then another silly hard left, but no sweeper before it. and it doesnt happen there at all.

feels just like what happens when you make too fast a turn on a low fuel tank

I wasnt logging fuel rail pressure, next time...

anyone else?

[orthojoe]

Welcome to the world of aftermarket power.

Sounds like fuel starvation to me. Your fuel pressure log would confirm. Larger fuel pump isn't the solution. A surge tank is. Been there. Done that. It's a slippery slope because there are other potential issues with running a surge tank.

Thanks for posting the info. This is valuable information to know.

[ft_sjo]

If it's not doing it when the tank is full then it should be fairly obvious what's happening.

You're going to need either an improved swirl pot in the tank, or look at an external one.

[HunterGreene]

Ok, I have a really stupid question, because I think I already know the answer (Which is: yes, they are)--you have the nannies off, right?

[7thgear]

i think you need more NOS.

[King Tut]

Originally Posted by Huehuecoyotl

Can not replicate with street tires
Must have R-comps, must be driving at 10/10s

10/10ths at a DE eh. I would like to see an EcuTek log file to diagnose what the issue is.

[CSG Mike]

Fuel starvation.
@robispec has a similar problem on left sweepers; he's on E85. I've discussed the issue extensively with him but will let him go into more detail. We have some speculation on the causes and fixes, and he'll be testing it shortly.

Do you have ANY datalog from when you get the starve? I may be able to extrapolate something from it.

Originally Posted by Huehuecoyotl

WOT thru sweeper --->STAND ON BRAKES--->downshift--->Turn FEVERISHLY(feathering throttle to rotate rear end at break neck speed)

Off topic, but this can be fixed via proper suspension balance (front/rear rates) and/or a 2 way LSD. You can alter it with sways, damping changes, or tire pressures, but those are all bandaid fixes.

[Huehuecoyotl]

Originally Posted by CSG Mike

Fuel starvation.
@robispec has a similar problem on left sweepers; he's on E85. I've discussed the issue extensively with him but will let him go into more detail. We have some speculation on the causes and fixes, and he'll be testing it shortly.

Do you have ANY datalog from when you get the starve? I may be able to extrapolate something from it.

csg, the car handling fine,TOO fine perhaps

... its a fast corner in both cases...pm me your email address and I send you logfile to look at
something needs to be done to allow the 'bowl to fill faster

I'm not babying it when it happens

[CSG Mike]

mike @t counterspacegarage d0t com

[robispec]

I think the car is not returning enough fuel to keep scavaging the fuel sloshed to the off side tank sump. the stock system does this using an "eductor" pump aka running extra fuel (the fuel exccess or the return fuel) by a nozzel set at an angle to the liquide flow wich pulls the fuel out of the rt sump and into the fuel pump antistarvation can.

[ftc~brz]

saw something on sprtsguys build about the tube inside the pump being pinched? just throwing it out there...

[naikaidriver]

I wonder if this is what killed the fuel supply to my car on a skid pad last month. I was also going left. Car wouldn't restart for 5 hours.

Scott

[CBR600RR]

have you considered getting fuel foam? it is more known in the morotcycle racing world to keep the fuel from sloshing back and forth and upsetting the bike in switchback turns.

teh foam comes in little cubes and is simply stuffed into the fuel tank right up to the brim. it displaces next to no volume of the tank too.

I am guessing that since it isn't happening to you at a full tank that fuel sloch is your problem, and since you are FI your pump is consuming fuel so fast that it is getting air when the fuel sloshes.

[jack43]

That reminds me why I changed my mind about wanting a Cayman: too many reports of engines blowing up in left turns. Search '987.1 oiling issues'.

Most are on the track w/ sticky tires but some are off-ramps etc on the street.