Throttle cutting out in hard left turns !!!

[Jforand]

So the fuel level is a good question. I honestly do not know, but I would venture to guess it was 3/4 or below. I filled up before hitting the track and it was my first time on AMP. It took a little while to learn the track and start getting comfortable. Obviously the speeds increase throughout the outing and the cutting happened more toward the end. I can easily see over 1/4 tank burn at that point.

I'm getting ready to two additional tract days this coming weekend (Summit Point) and another at the beginning of Nov (VIR) so I'll try to pay attention there, but I don't think I will experience the issue. I have been to VIR before and not experienced it. Atlanta Motorsports Park (AMP) has longer sustained turns.

I guess the one thing that is bugging me about this gas theory is the duration of the cutout. I would think fuel starvation would be pretty major. What I experienced was an uncharacteristic blip. A quick cut and then it is back to full power. Seems like a 'driver control' type thing, but I would not have said the car was getting away. I would also think that if it was on the verge of getting away, that this particular action might make the situation worse.

Seems there are arguments for both Nanny's and Fuel....

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[ddozier]

If it happens in a long sustained high G left hand turn it is fuel related. The fuel supply pump is on the drivers side and in high G left hand turns the fuel sloshes to the passenger side of the fuel tank and has to be pumped back to the drivers side of the tank.

When it first starts to happen in my car it is just how you described it at the end of a left hand turn as I start to straighten out the wheel and roll in the throttle the car acts like the engine is cut completely then within a second or so everything returns and is fine. If you continue to stay on track and run the fuel level lower and lower you will have the cut happen sooner and longer as you run through the left hand turns

If it is a nanny it will not cut power completely. It will attempt to use ABS if it is a slip angle that it senses or it will roll back the throttle and pull timing to reduce power of it is a wheel spin issue. Non of the nannys will completely shut down power unless there is a major mechanical/electrical issue. If that happened you will get a code.

If you want to know for sure. Use a SCT X4 or Nguage and log fuel pressure when you are on track. If it happens and fuel pressure drops it is definitely a fuel delivery issue.

Dave

 

[Jforand]

Nightmare...No, I was running in 'Normal' mode at the time.

 

[Jforand]

ddozier.....I looked at your scan tool, yikes! I believe I am going to opt for a significantly more economical one that can stream data to the phone. Not sure which one yet, but I did see that fuel pressure was a parameter on at least a few of them. I guess I might run into a potential sampling rate issue with cheaper models.

So I guess the idea is that the foam in the tank simply slows the mechanical sloshing of fuel tot he other side of the tank. It serves as a sort of time delay buffer? From the pic on Jegs it looks like fuel would/should flow right through it fairly quickly. I guess you have found otherwise.

 

[ddozier]

ddozier.....I looked at your scan tool, yikes! I believe I am going to opt for a significantly more economical one that can stream data to the phone. Not sure which one yet, but I did see that fuel pressure was a parameter on at least a few of them. I guess I might run into a potential sampling rate issue with cheaper models.

So I guess the idea is that the foam in the tank simply slows the mechanical sloshing of fuel tot he other side of the tank. It serves as a sort of time delay buffer? From the pic on Jegs it looks like fuel would/should flow right through it fairly quickly. I guess you have found otherwise.

I assumed you already had your car tuned and as a result most likely already had an X4 or NGueage, my bad. Almost any scan tool will do the job. Anyone that supports Fords Medium-Speed CAN (MS-CAN) will have plenty of speed to monitor the PID.

This one is very popular:
https://store.mp3car.com/products/o...rJGTLmaZvX7G5EtZn7lkL1qVutjBeVusmbxoCnq3w_wcB

If the foam is uncompressed fuel can move through it but it still has an effect on the sloshing of the fuel, in this application the foam is greatly compressed due to the size of the space it occupies. I have found that it allowed me to go from 3/4 tank and having the issue to 1/4 tank before the issue shows up.

Dave

 

[NightmareMoon]

As you improve and go faster you may find stability control cutting in more and more. If you switch to Sport or Track mode the limits are higher and higher. If you get any similar cutouts on right hand turns I think we can safely identify this as due to Stability Control.

When the nannies kick in, as ddozier explains, it doesnt entirely cut power 100% which would lurch you forward pretty bad, but it still feels like a significant and sudden power loss.

 

[Jforand]

Very good points for both of you. Hard to argue either.

I did come across that scanner, but it seems to be limited to Android devices. Are you aware of one worth its metal in the IOS realm?

 

[thatonenozz]

I am experiencing the same thing immediately following hard left turns as well. I rewatched my track video from the weekend and it cuts when I start to straighten the wheel after almost any left. This does not happen during the first several laps, only later on in the session. I never had this issue before installing my fore return fuel system, so I think the fueling diagnosis might be accurate. [MENTION=20846]ddozier[/MENTION] can you explain your fuel tank foam trick a little more? I'm very interested in giving this a go

 

[ddozier]

I am experiencing the same thing immediately following hard left turns as well. I rewatched my track video from the weekend and it cuts when I start to straighten the wheel after almost any left. This does not happen during the first several laps, only later on in the session. I never had this issue before installing my fore return fuel system, so I think the fueling diagnosis might be accurate. [MENTION=20846]ddozier[/MENTION] can you explain your fuel tank foam trick a little more? I'm very interested in giving this a go

Maybe a picture will help, I only had pics on the web to work with but maybe this will give you guys a better idea of what you are trying to do.

I will warn you, fuel cell foam can degrade over time and depending on the type of fuel used may need to be replaced sooner. Most foam is rated to last 5 years or so but many run it longer without issue. when it starts to degrade it will clog the fuel pickup filter at the pump and require a thorough cleaning to remove all the little pieces and a new piece of foam.

Dave

 

[thatonenozz]

Thank you, Dave! Any decrease in fuel capacity with adding the block of foam? Also, have you had and experience using the foam with E85?

 

[wildcatgoal]

I just did AMP yesterday and didn't get any throttle cut out unless I went into oversteer on turn 6 (I think it was; hard right turn) even in track mode. I would rather it not cut out throttle so much but I guess I don't want to have any risk to my "Capital One-owned" car. I did notice that my car felt like it had turbo lag in lower RPMs right after that turn in 3rd gear and then all of a sudden kicked in half way to the next turn - it was f'ing annoying, but I guess not unexpected as I probably should have gone to 2nd gear coming out of that turn, but that'd mean a shift instead of full concentration on my lines, which was the goal being I am a novice. Maybe I just don't know what the fuel cut off would feel like... I mean I wasn't as much focused on power. I did really well, I think, and I was really impressed with my suspension and the OEM PZero tires that I used on my stock PP rims. Well, they got progressively worse especially in the last two sessions but I was also much more confident and pushing the car in places I wasn't comfortable doing so before, so I may have just met their limit or (most likely) deviated from a smooth/ideal racing line. But I digress...

 

[ddozier]

Thank you, Dave! Any decrease in fuel capacity with adding the block of foam? Also, have you had and experience using the foam with E85?

I have not used the foam with E85, capacity will not really change much maybe a 1/8 or 1/16th of a gallon. In Fuel cells they are usually completely full of the foam material top to bottom.

Dave

 

[Jforand]

Thanks for the info ddozier.

I went ahead and ordered this OBD 2 unit

http://www.obdlink.com/mxwf/

With respect to AMP and the lag. I have the GT PP with the 3.73 torsen rear end. I found the gearing on this particular track to be a little annoying/mismatched. I was either too hitting the rev limiter prior to a corner or thinking I needed a lower gear coming out of a corner. This of course could be changed by throwing in all those 'extra' shifts, but I would make the argument that those shifts would actually make you slower. For instance, grabbing the next gear up to get off the rev limiter 2-3 seconds before the braking zone for a corner....and extra upshift to be met with n almost immediate downshift just to get you to where you were before.....I think 'coasting' for the 2-3 seconds will prove faster. Changing/shifting the ratios would be of interest to me if I was going to be spending a lot of time on AMP. By augmenting the rear end a tad I think the windows would shift and you could be in the power better coming out and on the power all the way to the braking zone.

My 2 cents on the Mustang GT 6-speed (essentially stock) and AMP.

 

[ddozier]

Thanks for the info ddozier.

I went ahead and ordered this OBD 2 unit

http://www.obdlink.com/mxwf/

With respect to AMP and the lag. I have the GT PP with the 3.73 torsen rear end. I found the gearing on this particular track to be a little annoying/mismatched. I was either too hitting the rev limiter prior to a corner or thinking I needed a lower gear coming out of a corner. This of course could be changed by throwing in all those 'extra' shifts, but I would make the argument that those shifts would actually make you slower. For instance, grabbing the next gear up to get off the rev limiter 2-3 seconds before the braking zone for a corner....and extra upshift to be met with n almost immediate downshift just to get you to where you were before.....I think 'coasting' for the 2-3 seconds will prove faster. Changing/shifting the ratios would be of interest to me if I was going to be spending a lot of time on AMP. By augmenting the rear end a tad I think the windows would shift and you could be in the power better coming out and on the power all the way to the braking zone.

My 2 cents on the Mustang GT 6-speed (essentially stock) and AMP.

The gearing for most tracks is a little off, you can tell Ford was wanting to augment the lack of low end TQ and used gearing to help that out, great for drag race guys not so hot for road race guys. However they did help us out by building a great little engine that loves to rev and can do it safely past the current 6750 RPM red line. By simple tuning the car to allow for another 750 RPM moving the red line to 7500 RPM and you now have a car that will be able to hold the lower gear longer and in most cases is better suited to track use. This does present another issue, the car will continue to pull in the upper RPMs but it is well past its peak TQ and will be running out of air the further you go past 6500. That is why a lot of guys are changing to the GT350, Boss, or CobraJet intake.

If you are worried about the new RPM limit or saving your warranty you can use the Ford Racing Power Packs and get the gains without loosing your warranty. By the way Ford raises the Rev Limiter to 7500 in the Stage 3 Power Pack with no mechanical engine upgrades just the intake system and a tune.

I have not done the GT350 Intake yet, it is on my winter projects list, I do have the car tuned to a 7500 RPM Limiter and having the extra room to stay in gear and not having to do the extra shift makes a huge difference. Even with the 7500 limit I find that on most tracks I do not need all the added head room and usually end up shifting around 7200 RPMs. Every track and driver will be different and you also have to factor in overall tire size as it will effect the final drive ratios as well.

That OBDII Dongle is a good choice and as a bonus it works with Harry's Lap Timer so you can log performance data and engine data in a single app.

Dave

 

[wildcatgoal]

Thanks for the info ddozier.

I went ahead and ordered this OBD 2 unit

http://www.obdlink.com/mxwf/

With respect to AMP and the lag. I have the GT PP with the 3.73 torsen rear end. I found the gearing on this particular track to be a little annoying/mismatched. I was either too hitting the rev limiter prior to a corner or thinking I needed a lower gear coming out of a corner. This of course could be changed by throwing in all those 'extra' shifts, but I would make the argument that those shifts would actually make you slower. For instance, grabbing the next gear up to get off the rev limiter 2-3 seconds before the braking zone for a corner....and extra upshift to be met with n almost immediate downshift just to get you to where you were before.....I think 'coasting' for the 2-3 seconds will prove faster. Changing/shifting the ratios would be of interest to me if I was going to be spending a lot of time on AMP. By augmenting the rear end a tad I think the windows would shift and you could be in the power better coming out and on the power all the way to the braking zone.

My 2 cents on the Mustang GT 6-speed (essentially stock) and AMP.

Agreed. I didn't shift, usually, but felt I should. I may invest in 3.55s because in ALL instances I drive this car, I wish for them. Track, strip, commute, mountain, yellow brick road, whatever.

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