Can Traction Control kicking in cause detonation at WOT/BOOST?

[SIZEMOREMK]

Of course one turns off the Traction Control when ready to play, but lets say you forget to turn it off now and again at WOT under boost.

How bad is that?

I was talking to an LS guy, that is admittedly not a gearhead, but said that he was reading in a LS forum somewhere that it could cause detonation due to leaning out the motor. He couldn't remember the specifics, but also read that it cause very severe overheating in some of the GM cars (I would assume maybe because of the detonation)???

I found some other generic things, even one on the Kenne Bell site that said it can cause the motor lean out.
http://kennebell.net/KBWebsite/Common/pdfs/46gtTechTips.pdf

I've heard some assumptions about what the traction control does on the MMs, seems everything from pulling timing, cutting fuel, applying brakes. Does anyone know for sure what exactly occurs when the TC kicks in with our cars? I'm curious what it does, how long, and how many times it does it?

I haven't purposely tried to experiment with it, but when I first got the car I tripped it a few times from a stop, but never got the distinct feeling that brakes were applied. All I could really tell was that power seemed slightly reduced for some short period of time from a launch. I seem to remember at least once where I tripped it coming out of a curve kinda hard and couldn’t really tell it did anything other than flashing the TC light.

I'm curious how the TC "feels" to some of ya'll when it gets tripped?

I have experimented with a newer stock Taurus I rented in snow/ice conditions, and I can verify whatever its TC does is much more aggressive than a MM. I could floor it on an ice patch and not lose control of the car.

If the fuel was reduced during WOT/boost I could of course see the problem going lean. But if fuel is cut completely for some period of time under WOT/BOOST, is there a reason that is particularly bad?

Or might it be that fuel is cut for a very short period of time, causing a generic shock to the engine when fuel comes back on, or does the fuel cycle on and off quickly for some period of time? Or does it cut fuel to some cylinders and not others?


I ask because I pretty much blew a motor (MMR 600 with cast crank, forged rods/pistons) where the shops opinion was that it looked like the engine had been detonating for some time due to the condition of the bearings and such (quite shiny on the top and bottoms of the bearings). There were never any indications of detonation that I noticed, and the tune was quite conservative at my request as this is my daily driver.

Not assuming this is what happened but curious. I will admit that I have two widebands that I probably didn’t monitor or datalog nearly enough; also have the SCT iTSX device that I should have been using to more closely monitor the fuel pump duty cycle and such as well. I know it could have been a number of things like fuel pump going out, bad tank of gas, etc. Just trying to prepare to fight off detonation in the new engine that’s fixing to go in.

Just wondering if perhaps several incidents of tripping the TC when in boost might have contributed to the engine failure.

Any thoughts?

[Bluerauder]

I'm curious how the TC "feels" to some of ya'll when it gets tripped?

It depends on the specific situation that caused the traction control to engage. I've barely noticed the light activating/flashing when I had the rear end kick out on me a couple times. Of course, I had already felt the problem and had come off the throttle anyway.

One guy reported that in snow/slippery conditions, he tried to accelerate into traffic and the more throttle he applied, the more the car pulled power. Of course it did, it was already spinning like crazy.,

If you are driving correctly and reacting properly to conditions, I seriously doubt that you would notice much at all. Now if you were intentionally wanting to spin, burnout, slide and do donuts --- then Traction Control Off is the way to go.

[Jeronimojc]

I thought TC pulled timing and applied ABS. If so, wouldn't detonation be less likely?


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[chief455]

I've wondered this myself.
Can someone explain, with certainty, what the PCM does when traction control is engaged due to engine power?
If fuel is reduced as a constant, that would trouble me, during boost.

[lifespeed]

This is purely a guess, but I am going to go with shutting off injectors cycle by cycle.

[fastblackmerc]

Good info on how traction control works.

http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/traction-control.htm

[fastblackmerc]

Actually the owners manual has this:

Page 115

"TRACTION CONTROL
Your vehicle may be equipped with the optional Traction Control
system. This system helps you maintain the stability and steer-ability of
your vehicle. It is especially useful on slippery and/or hilly road surfaces.
The system operates by detecting and controlling wheel spin. The system
borrows many of the electronic and mechanical elements already present
in the anti-lock braking system (ABS).
Wheel-speed sensors allow excess rear wheel spin to be detected by the
Traction Control portion of the ABS computer. Any excessive wheel
spin is controlled by automatically applying and releasing the rear brakes
in conjunction with engine torque reductions. Engine torque reduction is
realized via the fully electronic spark and fuel injection systems. This
process is very sensitive to driving conditions and very fast acting. The
rear wheels “search” for optimum traction several times a second and
adjustments are made accordingly.
Aggressive driving in any road conditions can cause you to lose
control of your vehicle increasing the risk of severe personal
injury or property damage. The occurrence of an Traction Control
event is an indication that at least some of the tires have exceeded
their ability to grip the road; this may lead to an increased risk of loss
of vehicle control, vehicle rollover, personal injury and death. If you
experience a severe road event, SLOW DOWN.
The Traction Control system will allow your vehicle to make better use
of available traction on slippery surfaces while you are trying to
accelerate or while your foot is on the accelerator pedal. The system is a
driver aid which makes your vehicle easier to handle primarily on snow
and ice covered roads."

[chief455]

Good info on how traction control works.

http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/traction-control.htm
kind of, sort of.
It says brake pressure is applied, but never get's into timing, fuel or throttle being pulled out.
Also, the pic on page 4 says a Chevrolet Camaro burning rubber, and the pictures is of a 'Cuda.
How much do these guys really know? ;)

[justbob]

I would assume pulling fuel is equal to the pulled timing, none at all, or possibly even adding fuel as less fuel makes more power..


Builder Of Badassery

[chief455]

I would assume pulling fuel is equal to the pulled timing, none at all, or possibly even adding fuel as less fuel makes more power..


Builder Of Badassery
interesting point.
I know rev limiters work in different ways = some drop spark to cylinders, some cut fuel supply. Smart ones that reduce spark to individual cylinders.
As the original question of the thread, I'd hate to have TC tell my PCM to cut fuel supply to any or all my injectors, under a boost condition.

[Jeronimojc]

Actually the owners manual has this:



Page 115



"TRACTION CONTROL... The system borrows many of the electronic and mechanical elements already present in the anti-lock braking system (ABS).

... in conjunction with engine torque reductions. Engine torque reduction is realized via the fully electronic spark and fuel injection systems..."


It makes sense that TC would borrow from systems already present. We also know knock sensors pull timing so I can see how TC could borrow from this function also, in addition to borrowing from the fuel injection system. I can't imagine a condition where TC engagement would result in engine knock, but what do I know.


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[chief455]

It makes sense that TC would borrow from systems already present. We also know knock sensors pull timing so I can see how TC could borrow from this function also, in addition to borrowing from the fuel injection system. I can't imagine a condition where TC engagement would result in engine knock, but what do I know.


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My concern is the factory did not include forced induction during TC logic. Pulling fuel to slow an N/A engine = no big deal, but under boost :eek:

Until I get conclusive data, maybe datalog a TC condition and look at fuel parameters, I'm turning that TC switch off.;)

[Jeronimojc]

Until I get conclusive data, maybe datalog a TC condition and look at fuel parameters


Good idea, but include timing in your data logging.



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[chief455]

Good idea, but include timing in your data logging.



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:beer: yup, I'll evaluate as much data as recorded to see what goes on for myself. Then I'll do it again at WOT and read data. If fuel is not effected, but timing is retarded under TC engaged, I'll breath easy and leave it on during daily driving.

[lifespeed]

From what I have noticed it feels like cylinders are shut down. I suspect they shut down the injector entirely for that cycle, which should not result in any effect on the mixture.

[chief455]

From what I have noticed it feels like cylinders are shut down. I suspect they shut down the injector entirely for that cycle, which should not result in any effect on the mixture.
so I'm at WOT, blower forcing air mapped to match fuel for set air fuel ratio, suddenly TC says "stop fuel to cylinder 8", won't the air still go through the intake valve and have no fuel on the compression stroke? Granted, spark on that cycle should have no fuel to ignite, but what if...?
If the injector and spark were cut to the same cylinder for a cycle I could relate.
Am I missing something?

[Logizyme]

The only issue with traction control would be detonation caused by a lean mixture, which would only happen if the fuel was reduced slightly - doing that from the factory is very unlikely - and would be problematic both N/A and boosted(more so boosted)

If the fuel is shut of completely(or significantly) there can be no detonation - just air running through the motor. The 2v has a failsafe mode that when the PCM detects excessive cylinder head temperature it will shut off fuel to 4/8 cylinders and constantly alternate which cylinders to run cool air through the engine to cool it.

Pulling timing might work but I do not imagine it to be effective enough to bother using for traction control.

Pulling spark timing or turning off spark would work, but would definitely not happen from the factory as it would be damaging to the catalysts.

[Jeronimojc]

Pulling timing might work but I do not imagine it to be effective enough to bother using for traction control.



How about pulling timing combined with ABS?


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[chief455]

from FordMuscleForums:

Ford techs:How does the \"Traction control\" work on the new Mustangs. 2004

The Bosch traction control system works at all speeds: Whenever wheelspin is detected, the system retards ignition timing, cuts fuel flow, and activates the brakes at one or both drive wheels, in that order. The driver can turn the system off with a console switch.

But, that is in supercharged Cobras, so guessing they considered avoiding lean conditions.

[DEFYANT]

I've been blown since 2005 with 5K on the clock. Defyant Marauder now rests comfortably in the garage with over 85K on the clock. Countless trips at the track and WOT blasts. On occasion, the pilot would forget that wretched traction control button.

Aside from looking like a dork, it has never been a problem!

[chief455]

I've been blown since 2005 with 5K on the clock. Defyant Marauder now rests comfortably in the garage with over 85K on the clock. Countless trips at the track and WOT blasts. On occasion, the pilot would forget that wretched traction control button.

Aside from looking like a dork, it has never been a problem!

Nice report card!;)

I sent an email to Bosch, waiting on a reply.
I believe at this point whatever fuel reduction method the system does is not risking detonation by leaning out, but hoping they will explain exactly how fuel is reduced during TC engagement.

[Marauderjack]

How about the "Rev Limiter"........does it shut off fuel or ignition??:confused:

Shutting off fuel could really be disastrous on a blower motor!!:eek::(

[SIZEMOREMK]

How about the "Rev Limiter"........does it shut off fuel or ignition??:confused:

Shutting off fuel could really be disastrous on a blower motor!!:eek::(


Seems like if it only cut ignition, you'd end up with a bunch of un-burnt fuel in the exhaust that would likely go boom.

I can see reducing fuel causing big problems going lean; but cutting fuel for some percentage of cycles, I don't see what the issue is. If for a particular cylinders compression stroke, there is no fuel, I don't see the problem?

I have been looking into the racelogic aftermarket traction control unit, and it essentially cuts fuel by some fine tunable rate.

This unit seems quite popular with some Japanese and Euro cars, I see evidence that a guy with a 96 cobra used it, but not sure how it worked out. Also read somewhere that someone used one on a Lightening truck...

http://www.svtperformance.com/forums/showthread.php?905466-Tried-out-the-traction-control-for-the-first-time-tonight

http://www.svtperformance.com/forums/showthread.php?888305-Planning-on-an-aftermarket-traction-control-(-a-bit-long-read-)

https://www.youtube.com/watch?v=q1D9eANYyBc

https://www.youtube.com/watch?v=TUtoG98NzQs

This definitely has my interest peaked. I actually emailed the company to see what experience they have with these on a ford...

[lifespeed]

How about the "Rev Limiter"........does it shut off fuel or ignition??:confused:

Shutting off fuel could really be disastrous on a blower motor!!:eek::(

On fuel injected motors, limiting is pretty much always done by shutting off fuel. They're not going to wash down the cylinder walls with unburned fuel (cut spark only) and blow it through the catalyst.

Turning off an injector for one entire cycle does not alter the mixture, the affected cylinder does not fire at all - just like turning off a spark plug in the carburetor days - without the wasted fuel.

A minor torque reduction can be done by retarding ignition timing. This is often the way it is done in some limiting algorithms that are designed to smooth automatic transmission shifts, for example. But really cutting back the power requires shutting down cylinders and this is done by cutting the fuel completely.

[GetMeMyStogie]

Would there be an increase in load on the engine (like when you do a brake stand)? I suppose retarding the engine timing on the cylinders that are firing would counter any load increase.