Trail Braking

Reinout

Reinout

Member
I wasn't able to find it on this forum or elsewhere so please bear with me.

Where I live, up a long dirt road with ruts and washouts, it would be great to be able to trail-brake like I could in our 3rd gen. Why? So that when the wheels drop into ruts and washouts it's less harsh since the braking keeps the wheels from dropping, making it more controlled. At the same time keeping some form of accelaration would be great. The 4th gen cuts the throttle when you brake.

Has anyone found a solution that allows the brake and throttle to be simultaniously used?
 
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Reinout said:
I wasn't able to find it on this forum or elsewhere so please bear with me.

Where I live, up a long dirt road with ruts and washouts, it would be great to be able to trail-brake like I could in our 3rd gen. Why? So that when the wheels drop into ruts and washouts it's less harsh since the braking keeps the wheels from dropping, making it more controlled. At the same time keeping some form of accelaration would be great. The 4th gen cuts the throttle when you brake.

Has anyone found a solution that allows the brake and throttle to be simultaniously used?
Click to expand...

No solution here, but I think you mean left foot braking?

I know it works in my '00 Taco, and I will have to try this in the 5th gen. I think it works fine?
 
Put the transfer case in low range.

I'd imagine you went through brake pads like crazy in your 3rd gen.
 
Seems like there was some recall way back for this where toyota did an ECU/computer mod to "fix" it.

I never did the recall, i can gas and brake at the same time and it wont cut the throttle.
 
Reinout said:
I wasn't able to find it on this forum or elsewhere so please bear with me.

Where I live, up a long dirt road with ruts and washouts, it would be great to be able to trail-brake like I could in our 3rd gen. Why? So that when the wheels drop into ruts and washouts it's less harsh since the braking keeps the wheels from dropping, making it more controlled. At the same time keeping some form of accelaration would be great. The 4th gen cuts the throttle when you brake.

Has anyone found a solution that allows the brake and throttle to be simultaniously used?
Click to expand...

You can! At least with an early 2003 year 4th gen!
When I used to "Performance Drive" my 4runner I picked up the habit of Left-Foot-Braking. I used it to rotate the car during turns because my old bias ply's were very vague about their limits of grip.

Now I really only use it now to coax a downshift in low grip. (can be done with sharp brake pulse and a throttle stab.)
Heading out to some gravel roads later to record. Going to duct tape the phone to my forehead.


Be easy on the brakes don't let the ABS engage or the TCS or VSC go off. There are ways to disable it especially on later models. Brake a little earlier than you would with the 3rd gen as the 4th gen is much much heavier.
Same as usual for the actual trail braking though brake through the corner while letting off the brake as you add steering input. Manage the weight transfer to the front with left foot braking.
No need to worry about forcing downshifts to reduce understeer if you're using the 2WD (just going from your post signature you've got a 2wd i think) (v8's tend to have a clunky braking feel as they downshift due to the full time 4wd's, they also feel like it "snaps"/wobbles under harsh braking.)
Recommend rotating the car on corner entry to induce understeer and allow for nose to be pointing the right direction
.
DO NOT DO THIS KIND OF DRIVING WITH THE CENTER DIFF LOCKED. IT WILL BIND. I'm not sure about the 4-Lo on the 2wd's but for the full time 4wd's I personally wouldn't. Even in poor driving conditions.


I would assume it's cutting the throttle because it thinks it's sliding. Whether it's ABS does it or not i don't know.

(Edit: The TSC and VSC completely cut throttle control if it detects the tail is sliding. In my 03 I haven't found a way to get throttle to re apply with the two systems enabled. If you trick the ECU into thinking the center diff is locked it can disable them, but I have yet to do that. I had a friend of mine disconnect the sensors then and that also disables them.)

Worth noting the TCS and VSC on the early 4th gens only seem work if the rear is sliding. I don't think it considers understeer a scenario where it should cut throttle, so it's better to have some understeer through the corner entrance and exit.


I have heard that if you brake too harsh in one moment the 4th gen enters a "Panic Stop" mode. I don't really brake to the point ABS engages since you need to conserve energy at all costs to keep the 4runner fast. So I can't really speak for it.

Will record something later.
 
Last edited:
itr1275 said:
No solution here, but I think you mean left foot braking?

I know it works in my '00 Taco, and I will have to try this in the 5th gen. I think it works fine?
Click to expand...

I think you can call it left-foot braking, however it's more than just braking with your left foot. It's also staying on the accellerator.

It does work on our 1997, which is manual as well.

My 2011 VW doesn't allow left foot/trail braking either, and that's a manual.
 
Inv4drZm said:
Put the transfer case in low range.

I'd imagine you went through brake pads like crazy in your 3rd gen.
Click to expand...

Putting the transfer case in low will change the setting to allow left-foot/trail braking?

There's no reason to go through more brake pads than usual. Of course if you're driving with your foot on the brake all the time, yes. But this is a momentary thing. For off-road it's not to not drop the rear end into a drop too quick. For performance street driving (not in the 4runner) it's nice to be able to use left-foot braking while underaccelleration because it allows you to enter a turn with a different weight distribution.

But still, the driver that does it right isn't going to burn through brake pads significantly different.
 
Moist said:
You can! At least with an early 2003 year 4th gen!
When I used to "Performance Drive" my 4runner I picked up the habit of Left-Foot-Braking. I used it to rotate the car during turns because my old bias ply's were very vague about their limits of grip.

Now I really only use it now to coax a downshift in low grip. (can be done with sharp brake pulse and a throttle stab.)
Heading out to some gravel roads later to record. Going to duct tape the phone to my forehead.


Be easy on the brakes don't let the ABS engage or the TCS or VSC go off. There are ways to disable it especially on later models. Brake a little earlier than you would with the 3rd gen as the 4th gen is much much heavier.
Same as usual for the actual trail braking though brake through the corner while letting off the brake as you add steering input. Manage the weight transfer to the front with left foot braking.
No need to worry about forcing downshifts to reduce understeer if you're using the 2WD (just going from your post signature you've got a 2wd i think) (v8's tend to have a clunky braking feel as they downshift due to the full time 4wd's, they also feel like it "snaps"/wobbles under harsh braking.)
Recommend rotating the car on corner entry to induce understeer and allow for nose to be pointing the right direction
.
DO NOT DO THIS KIND OF DRIVING WITH THE CENTER DIFF LOCKED. IT WILL BIND. I'm not sure about the 4-Lo on the 2wd's but for the full time 4wd's I personally wouldn't. Even in poor driving conditions.


I would assume it's cutting the throttle because it thinks it's sliding. Whether it's ABS does it or not i don't know.

(Edit: The TSC and VSC completely cut throttle control if it detects the tail is sliding. In my 03 I haven't found a way to get throttle to re apply with the two systems enabled. If you trick the ECU into thinking the center diff is locked it can disable them, but I have yet to do that. I had a friend of mine disconnect the sensors then and that also disables them.)

Worth noting the TCS and VSC on the early 4th gens only seem work if the rear is sliding. I don't think it considers understeer a scenario where it should cut throttle, so it's better to have some understeer through the corner entrance and exit.


I have heard that if you brake too harsh in one moment the 4th gen enters a "Panic Stop" mode. I don't really brake to the point ABS engages since you need to conserve energy at all costs to keep the 4runner fast. So I can't really speak for it.

Will record something later.
Click to expand...

You made some great observations:
I have the 4x4 V6 from 2007.

Throttle cuts when using left-foot and throttle regardless of road condition or direction: IE it can be gravel/sand/tarmac/etc and in a straight line or going through a turn: it'll cut the throttle.

It's really a 1st world problem, but... well... It's something that's "missing for me.
 
I'm curious, does it also cut at very low speeds? I've gotten out of ice/snow by braking a little while giving it gas (so the open diffs would send power to both sides) and didn't notice it cutting power at all.
 
OSSGuy said:
I'm curious, does it also cut at very low speeds? I've gotten out of ice/snow by braking a little while giving it gas (so the open diffs would send power to both sides) and didn't notice it cutting power at all.
Click to expand...

Sorry for the late reply. Speed is irrelevant. If the I have the left foot on the brake and the right on the accelerator, the throttle is cut off.
 
Reinout said:
Sorry for the late reply. Speed is irrelevant. If the I have the left foot on the brake and the right on the accelerator, the throttle is cut off.
Click to expand...

Strange, my 06 V6 4wd doesn't do that at all. I remembered about this post a couple weeks ago and pressed the brake fairly hard with my left foot while I was going a steady 40mph (in 2WD on dry asphalt) with my right foot on the throttle. Besides sliding forward in my seat, not much happened. The engine didn't suddenly cut throttle, my RPMs just dropped a little as the brakes slowed us down. I wonder how common it is for 4Rs to cut throttle? Maybe you could swap ECUs to one that doesn't cut the throttle and sell they old one? Not sure how you'd tell if a used ECU cuts the throttle though, you might have to just roll the dice.
 
Reinout said:
I didn't see you say anything.

But it makes sense: if the sensor doesn't know that you're braking, then it can't cut the throttle....

Will experiment!
Click to expand...

Just don't forget to turn it back on when you're on the highway/in traffic. Or wheeling with a group. Don't want to get rear-ended because your brake lights don't work. You could probably wire up a relay to control the brake lights without sending the signal to the ECU, though...
 
OSSGuy said:
Strange, my 06 V6 4wd doesn't do that at all. I remembered about this post a couple weeks ago and pressed the brake fairly hard with my left foot while I was going a steady 40mph (in 2WD on dry asphalt) with my right foot on the throttle. Besides sliding forward in my seat, not much happened. The engine didn't suddenly cut throttle, my RPMs just dropped a little as the brakes slowed us down. I wonder how common it is for 4Rs to cut throttle? Maybe you could swap ECUs to one that doesn't cut the throttle and sell they old one? Not sure how you'd tell if a used ECU cuts the throttle though, you might have to just roll the dice.
Click to expand...

Mine cuts off regardless of the pressure of the brake applied except for maybe if I "rest" my foot against the brake (which I don't do except to test the cutoff).

I wonder if the Limited has a different ECU.

Honestly though, it's such a non-problem problem that getting an ECU is just throwing money away ☺
 
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