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Valve Body Mods, Giant Leaps Forward!!!


ClimberDHexMods

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what's wrong? I have a slew of power parts on my desk. I'm sorry if I sound forthcoming Dave, I'm just anxious

 

edit: I'm willing to be a test dummy for the vb mod...

 

do your mods ..

 

use manual mode and do you pulls after you shift. don't pull through the shifts

Now that's thinking out of the boxer!:lol:

fyi all 05 + legacy's have built in code reader

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Yes but do we know how much power the tranny can hold once in a gear? I always let off between shifts even now...i just dont want clutch slip as im doing a 3rd gear pull

 

i was under the impression that one should keep the throttle input the same/constant while going thru the shifts, and that letting off was the wrong thing to do.

 

ah these forums. so much (dis)information!

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The reason that was said was to reduce heat buildup via the TC. If the tc stays nearly engaged it will not prose internal friction to the atf. However, you have two options- stay on the throttle and slip between gears via the clutches, or heat up the atf by letting off between gears. Lol i know which one id pick!

 

Back on to my topic: im buggin out about the dyno tune once i get this 20g on :lol: 3rd gear pull after pull

Edited by bmx045
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i was under the impression that one should keep the throttle input the same/constant while going thru the shifts, and that letting off was the wrong thing to do.

 

ah these forums. so much (dis)information!

 

lol let right off is ok !

 

but don''t go to half!

 

i actually stayed full throttle shifted waited a second for the shift to start then blip the throttle. that gave the tranny a chance to pull the engine down. and make a awesome bov sound :D

Now that's thinking out of the boxer!:lol:

fyi all 05 + legacy's have built in code reader

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I don't have time to write a more complete post at the moment, but long story short you could install a 35r and if you drove it like a manual (no gas during the whole shift, every shift) then it would probably hold up just fine. Sounds like it would be no fun to drive this way though... Anyways the engineers of course knew this, which is why they programmed line pressure to be higher during a shift than during regular holding. F1 becomes necessary when you want to take advantage of the primary WOT benefit of a auto trans on a boosted car, which is to maintain full boost through every shift instead of doing the bucking bronco every single gear change like with the MT.

 

elsewhere question was asked what are the differences between 05-07 and 08-09 trans internally. The answer, not much changed, but there is a list that I will include in my eventual FAQ. The low coast brake goes byebye, and the forward brake switches from manual control (via shifter handle position) to electronic. So you lose one and gain another, thus same number of solenoids. Other differences are mostly along the lines of supporting this change. Thus a 08 VB is different enough to not be swappable with 05-07, even if you rip out all the VB controls and go standalone TCU (which I dream about doing one day :wub:); the ultimate way to do it right, in exchange for double the cost and exponentially more complexity (though Frank_ster or I could do it and thus anyone could)

Edited by ClimberD@HexMods
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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thanks Dave! Personally, I can live without wot during shifts, I always drive it like a manual anyway. I know it would be hard to determine but the reason i asked about internal differences was because I know of a few 05 5eat's that hold the power of a 20'g when in manual mode doing dyno pulls. Wasn't sure if the power handling capability of the 05-06 and 07-09 were different. (I.E. clutch disc sizes, etc).
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thanks Dave! Personally, I can live without wot during shifts, I always drive it like a manual anyway. I know it would be hard to determine but the reason i asked about internal differences was because I know of a few 05 5eat's that hold the power of a 20'g when in manual mode doing dyno pulls. Wasn't sure if the power handling capability of the 05-06 and 07-09 were different. (I.E. clutch disc sizes, etc).

 

Nope "it's all in the tune" is the only real power holding difference. Heck one of my clients just blew his engine making roughly 400whp on E85 with stock trans and Hex F1, so it really is all about the tune, and tweaking it however you can (in this case mechanically). The powerband of a 20G is a lot like a Stage 0 LGT, just a lot more of it, which is why the trans manages as well or better than a Stage 2 car (power is not the first functional limitation the 5eat hits). Other major factors (quality of fluid, driving habits (I've gotten to know guys who have crazy expensive setups with tons of power, who NEVER USE ANY OF THE DAMN POWER OR TORQUE WHY?!?!, and of course luck, a simple word to sum up how not every trans (or engine or turbo or anything) rolls out of the factory with exactly the same material and tolerance precision. Put it all together, and you get one thing for sure: uncertainty.

 

Now I really have to go do my job. Off to Fort Worth...

Edited by ClimberD@HexMods
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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thanks Dave! Personally, I can live without wot during shifts, I always drive it like a manual anyway. I know it would be hard to determine but the reason i asked about internal differences was because I know of a few 05 5eat's that hold the power of a 20'g when in manual mode doing dyno pulls. Wasn't sure if the power handling capability of the 05-06 and 07-09 were different. (I.E. clutch disc sizes, etc).

 

IIRC you have more clutch packs in 3rd gear, so you would be also safer doing your pulls in 3rd gear than 4th, even though 4th I think is closer to one to one. I believe 4th & 5th share clutches, hence the reason I had extra 4th and 5th gear clutches added when I did my rebuild. This is why I think a lot of the 5EAT's fail from the top down causing us to drive around in 3EAT's until we can afford to get them fixed. :lol:

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I think it is still the shifts into 4th and 5th that cause the damage, not the holding capacity. 3rd to 4th seems to be much slower than 2nd to 3rd at wot.

 

But doing 4th gear pulls for tuning or logging is a bit nuts from the speed at redline.

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I re-read and things make more sense when I'm not skimming.

 

Hell, those 4eat's are pretty robust and hear they're easier to mod and work on since theyre hydraulic. All these damn electronic shits

 

No they're largely electronic, similar to the 5eat in that regard. They're easier to work on because they are simpler (2 planetary gear sets to fuss with instead of 3, and consequently less ratios to make). The victory with the 4eat is that the demand for modified 4eats is 10x what we have for the 5eat, so a lot more eyes fell on it. They are also a simpler transmission, which is great when you're the guy looking at how to make it better. And the documentation on it is far more clear. This wire goes here and does this. Makes for a lot less figuring stuff out. For the 5eat I found a description for what valve does what task, but it's a vaguely translated brief sentence and does not actually point out what valve is which. But yes there is overall a considerable amount less electronic things on it, partly due to the reasons mentioned. I don't know if there is similar learning on the 4eat, but I sure hope not, for their sake.

 

I think it is still the shifts into 4th and 5th that cause the damage, not the holding capacity. 3rd to 4th seems to be much slower than 2nd to 3rd at wot.

 

But doing 4th gear pulls for tuning or logging is a bit nuts from the speed at redline.

 

Correct, but IMO all the WOT shifts are WAY too slow for our purposes.

Agreed, no reason to do it in 4th since you can do it in 3rd without going crazy fast.

 

Yea it seems that way- i hear that wot in 5th and 4th is a way to roast em. Is that because of the shifting or the slip when its in the gear? Im pretty sure you just answered that.

 

Correct :) I'm sure I made a misleading comment a while back about how 4th and 5th are weaker, then just 5th weaker, but both times I found myself wrong. It just happens to be popular to fry the Input clutch (4th and 5th ratios) because those of us with bigger turbos do a lot of damage shifting out of 3rd into 4th at full boost (OUCH), or on the highway hitting the gas in 5th and spooling the turbo, and automatically dropping to 4th while making a lot of power that inconveniently falls on a soft part of the requested torque graph. Either way using the steering wheel buttons/paddles ahead of gas pedal > floor solves problem. Or an F1.

 

I think frank_ster was tuning his boost in 5th on a stock 5eat, so...I think it can take some power.

 

Doesn't make sense to do so unless you can tune per gear in MS, which I think you can :wub:

Edited by ClimberD@HexMods
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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With the hexmod f1 shifting WOT at nearly 500whp doesn't slip.. If some are concerned. I will have a video up before the beginning of next week. The only chance I believe there would be an issue slipping is if you shifted too soon making high power at a lower RPM level in a higher gear.

512whp/465ftlb 2005 5EAT Legacy (Build Log)

Videos -

-

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Correct :) I'm sure I made a misleading comment a while back about how 4th and 5th are weaker, then just 5th weaker, but both times I found myself wrong. It just happens to be popular to fry the Input clutch (4th and 5th ratios) because those of us with bigger turbos do a lot of damage shifting out of 3rd into 4th at full boost (OUCH), or on the highway hitting the gas in 5th and spooling the turbo, and automatically dropping to 4th while making a lot of power that inconveniently falls on a soft part of the requested torque graph. Either way using the steering wheel buttons/paddles ahead of gas pedal > floor solves problem. Or an F1.

 

So it's the actual shifting on wot between 3-4-5 is what causes them(4th and 5th) to roast? I wasn't sure if it's infact the clutches for 4th and 5th being weak while in gear, or it's the inheretant slow shifting(low rt point) thats slipping and roasting...while on wot

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What is my wife doing in your avatar???

 

Don't over analyze it.

For a healthy transmission (no burned clutch packs, no case hardened steels, all tolerances in good spec), you're going to do all the damage during a shift. It is the exact same rule for MT cars' single clutch @ flywheel. If you never shift, then the static bind is very strong, and will last forever. If you gently shift from one gear to the next, and slowly let out on the clutch, the wear is minimal. Conversely, if you are trying to drop the clutch at WOT, you're going to get some friction as it engages and thus some wear. If you let out the clutch SLOWLY at WOT, you will get a more comfortable engagement, but a lot of friction and a general lack of sportiness. If you drop the clutch quickly at WOT, you get a harsh engagement but a lot less wear. This is because the slow engagement has an extended period of friction, worsened by the creation of heat, as where the quick engagement instead clamps with less duration of dynamic friction, instead putting more stress and strain on the hard rotating components (which are fortunately very strong with the Jatco RE5 platform). I realize you may need a flat foot shifting ECU hack to do this verbatim with a MT, but you generally get the point. Apply the same logic to the 5EAT. Clutches doing the engagement, except they are smaller so thus there are several more layers of them. Same difference.

So what can we gain from this?

It's not just 3-4-5, it's EVERY SHIFT. If you are going to accelerate through the gears, and not let off the gas during each shift, this is the logic to how it will wear. Since you can't control the shift firmness with your foot, you have to tweak what it will automatically do to get the desired balance between too comfortable and too firm, aka between too slow and too quick. So that's the what, and you have the why.

Keep it simple :)

 

Side note, FRKevin's turbo is so big he doesn't really reach full boost in 1st. So HIS situation is to be most concerned about 2>3, 3>4, 4>5, 5>4, and 5>4>3.

Conversely, a Stage 2 Legacy will be most worried about launching in 1st, 1>2, 2>1, and maybe some concern about 3rd as well.

Edited by ClimberD@HexMods
[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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