E40D Why question
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Tuned
Joined: Feb 2004
Posts: 343
Likes: 30
From: Maryville, TN
E40D Why question
So searching/reading through here I see that the E40D/Torque Converter interacts with the reverse sensor and brake lights. What I can't seem to determine is why.
I can feel that reverse seems to be more direct then 1st or 2nd forward gears (pressure increase maybe). But the brake lights I don't understand at all.
Anyone care to elaborate?
Bob
I can feel that reverse seems to be more direct then 1st or 2nd forward gears (pressure increase maybe). But the brake lights I don't understand at all.
Anyone care to elaborate?
Bob
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Joined: Apr 2008
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I have no idea why it looks for the reverse, but Lazy K is right on why it looks for the brakes - if you floor your brakes and the converter don't unlock you may end up damaging the converter as on one end you have the engine trying to turn it, and on the other end you have the driveline trying to stop it. This is exactly why I wired up an interrupter relay when I installed my manual lockup switch, this way the moment I touch the brake pedal the converter unlocks and I can then stand on the brakes if I want to and no damage occurs. Now why the PCM looks at the brake lights, and not the BOO switch on the pedal, that I have no idea about, seems to me it's a pretty dumb idea as when a brake light goes out it sometimes throws the PCM into failure management (limp-home) mode - my lockup interrupter relay is triggered by the BOO switch, so as far as converter is concerned I couldn't care less if the brake lights are working or not.
Thread Starter
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Tuned
Joined: Feb 2004
Posts: 343
Likes: 30
From: Maryville, TN
I guess my confusion stems from that fact that the converter already unlocks as soon as the throttle is released (which I find most annoying) and sensing the brake lights seems somewhat redundant.
Oh well, sometimes I think understanding the Ford engineers logic must be above my pay grade.
Thanks
Bob
Oh well, sometimes I think understanding the Ford engineers logic must be above my pay grade.
Thanks
Bob
Senior User
Joined: Nov 2008
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From: Western Australia
I had an idea a while back to put a foot operated momentary switch on the floor conected to the converter lock up and an exhaust brake for those down hill runs that I seem to do a lot of. Does this sound feasable and is there any damage likley? How hard is it to make a manual lockup.
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I put my switch on the shifter, and that's also where I moved the OD cancel button (your OD button is already on the shifter), it makes it easier to operate for me. Wiring up a manual lockup is pretty easy actually, I think I posted the diagrams on here somewhere...
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Post Fiend
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From: Faibanks Ak.
I have zero experiance with the E40D but woildn't the lockup converter in it's stock confirureation make the exhaust brake useless when you needed to use the brakes.
Besides that how do you like the exhaust brake on the idi motor and does it build boost like a jake.
Besides that how do you like the exhaust brake on the idi motor and does it build boost like a jake.
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Yes, it would, hence why I have a full manual lockup control. As for the brakes, actually I'd rather have both the wheel brakes an the engine brake, but there's no easy way of achieving that. IIRC David85 programmed his Bauminator to lock up the converter over 30mph and keep it locked regardless of brake use, then under 30 mph it automatically unlocks and stays that way - the latter of which may at first seem undesirable, however under 30mph you really should be in 2nd gear anyways and there the engine braking is better with the converter open (I've tried it).
Senior User
Joined: Nov 2008
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From: Western Australia
Yes, it would, hence why I have a full manual lockup control. As for the brakes, actually I'd rather have both the wheel brakes an the engine brake, but there's no easy way of achieving that. IIRC David85 programmed his Bauminator to lock up the converter over 30mph and keep it locked regardless of brake use, then under 30 mph it automatically unlocks and stays that way - the latter of which may at first seem undesirable, however under 30mph you really should be in 2nd gear anyways and there the engine braking is better with the converter open (I've tried it).
Post Fiend
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From: Faibanks Ak.
I don't know anyone with an exhaust brake on an idi. I can't see why they would damage the turbo or engine though. The dodge guys have installed them forever and now they all come stock with them. some of the cummins big truck motors used them instead of a jake from the factory. the principle is the same just 8 cylinders instead of 6.
They will show you if you have an exhaust leak though.
They will show you if you have an exhaust leak though.
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From: Southern Oregon USA
I have a factory exhaust brake on my Dodge. It is a bit different from the typical add on aftermarket EB as it is a design function of the VG turbo. The TC locks any time the brake is on and you let off the throttle. With the converter unlocked, there is little to no compression braking.
I've heard about exhaust brakes causing valvetrain damage on the IDI because of the hydraulic lifters. Yet, if I am not mistaken, there are EB's available for the PSD. If the engine was prone to damage because of increased backpressure, how much damage is being caused by increasing the boost at the other end? I personally don't think these engines are that fragile. The EB doesn't completely shut off exhaust flow, just slows it down.
Jason
I've heard about exhaust brakes causing valvetrain damage on the IDI because of the hydraulic lifters. Yet, if I am not mistaken, there are EB's available for the PSD. If the engine was prone to damage because of increased backpressure, how much damage is being caused by increasing the boost at the other end? I personally don't think these engines are that fragile. The EB doesn't completely shut off exhaust flow, just slows it down.
Jason
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IIRC the exhaust brake designed for the IDIs runs lower backpressure (6psi max?) than the one for the PSD or the Cummins, not because of the lifters but because of the valve springs (which can be replaced with stiffer ones if needed).
And yes the converter will make more heat descending a hill in 2nd gear but on the way up the hill you're making the same heat if not more, so it ain't gonna be much different than your current heat-generation situation. You need a big cooler for that, not playing with the converter - my trans used to be purely air-cooled through the factory A/C condenser and it worked just fine, now it's back to radiator cooler and then again the A/C condenser for even better cooling when I run up and down the mountains with the converter unlocked. I still need to do the pump mods but I ain't pulling that beast any time soon... Another thought on locking up in 2nd - it's been rumored that it's not a good idea to do so, but I'm not sure exactly why - maybe because in manual 2nd there are different set of clutches applying then when she's in automatic 2nd? I know the factory setup will lock the converter halfway through 3rd and pretty much constantly in 4h, but never in 2nd or 1st...
And yes the converter will make more heat descending a hill in 2nd gear but on the way up the hill you're making the same heat if not more, so it ain't gonna be much different than your current heat-generation situation. You need a big cooler for that, not playing with the converter - my trans used to be purely air-cooled through the factory A/C condenser and it worked just fine, now it's back to radiator cooler and then again the A/C condenser for even better cooling when I run up and down the mountains with the converter unlocked. I still need to do the pump mods but I ain't pulling that beast any time soon... Another thought on locking up in 2nd - it's been rumored that it's not a good idea to do so, but I'm not sure exactly why - maybe because in manual 2nd there are different set of clutches applying then when she's in automatic 2nd? I know the factory setup will lock the converter halfway through 3rd and pretty much constantly in 4h, but never in 2nd or 1st...
