ClimberDHexMods

When my clutch packs were letting go in 3rd at peak torque, it was evidenced by chatter, shaking the whole car until I let up on the gas enough to let the clutches grab solid hold. By the time the trans is doing that, your trans is cooked. It took me a long time for it to wear that point, but eventually it reached its end, and the chatter was the notice to quit and find a different transmission, or to rebuild the existing one. Solution to overheating: bigger ATF cooler. I have only heard a few instances in which ATF lights came on, and all are under extended severe duty. Never heard of fuel cut though... different safety mapping sure.

Nice work!

It can be done, but normally the TC is not a problem. It doesn't try to lockup very often, never in 1st or 2nd, only manual mode in 3rd.

then you should be fine

I misread this. Thought you meant a resistor how it's typically used, on the LP solenoid. I don't know why my mind made that jump. That way has proven to work miserably via to IPT/MSprank experiment. TCU will just learn around it and neutralize the effect. Either way, if you are the type to read the FSM and figure out the way to do temp mods, go for it. I don't recommend it. It won't be the slam dunk you're after.

oh boy... it's one of those things where if you have to ask, don't do it. All these hack electrical fixes won't actually get your car anywhere near where it needs to be in terms of trans performance. I was just posting for the hell of it.

Nope I wish, you could just overcool the TCU and call it a day. Trouble is I have a collection of worn 5eats shipped in from cold places. My Texas transmission holds like super glue. Holy hell you may be on to something! TCU raises line pressure as temps go down (it reads ATF temp at two points). If you put a variable resistor on both of those, or any reasonable resistor, you could basically turn up line pressure. I have the sensor scaling if you want to play with it. Downside is you would lose 5th gear and TCC lockup. Upside is it would hold gears for longer, so more power at medium throttle. That combined with Sport mode may be good for autocross racing, but would be bad for the highway. If you did this with an F1, you would probably break the trans, since adding any more line pressure would be a bad idea. It's already as high as you would ever want to go, when warmed up. Another idea, just switch the temp sensors to ground, aka tell the TCU trans is overheating. There is a chance line pressure would be raised in an over-heat situation, to reduce friction. TCC would lock up, and 5th would work. Not sure if the TCC would respond to it as you would want though. Might end up being a waste of time. It's a real hack...

Depends, different from trans to trans, since they are all a little different. One of my clients on stock trans is doing around 400whp, which 400/.7=571bhp. But that's with WOT shifting as well. Lots of torque via E85. My worn trans at 30k ish miles would let go in middle of 3rd at 300whp, which at that point was a 100% replacement candidate. The limit is so high it's just silly. The problem is you wear out clutch packs quickly when shifting at a super high power level, even if you do all the right trans mods. So you don't get to enjoy stock-like longevity. But with any super high powered car, you best accept that you're going to pay a lot more to keep it on the road than the stock counterpart, so no big surprise there. I hear about guys who open up their modified 4L80Es after every drag weekend. They're also pretty fast...

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.

This validates my solution, to maintain PWM control but also have hardwire override, activated via boost switch. So at the + & - wires from fuel pump module to pump, cut and intercept with DPDT relay. Have relay switched by boost pressure switch. When switched, relay directs power from fused thicker gauge wire direct from battery, through relay to fuel pump, back to relay and to ground (fuel pump module bypassed entirely). Could easily add a Boost-a-pump to the boost-switched circuit, so not only would you have BAP but you would have it on its own heavier gauge circuit. You may have to wire up a resistor to fool the fuel pump module, which would add some more complexity with second relay, but long story short the car would be all OEM-controlled while off boost, which would be nice!

I re-read and things make more sense when I'm not skimming. 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. 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. 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. Doesn't make sense to do so unless you can tune per gear in MS, which I think you can

Most of this is incorrect

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...

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 ); 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)

Stop. Asking. I. Am. Working. On. It. You can get all the IPT work in the world done to your 08, but I know with absolute objective certainty you will end up spending a fortune and getting a product that shifts and holds power with inferiority. It makes no difference to me what anyone plans or buys. The product will be ready when it's ready, end of story. If you want to go with IPT, more power to you. But as a reminder, people aren't shipping me their IPT VBs for a F1 conversion just because they like my pink avatar. Well... maybe they are... I never asked...

One step ahead on surveys and an FAQ. Not excited to type out an entire FAQ, but it would be for the best.

For the few complaints: 1) Slam from P/N to D - I will be testing a fix; may have this figured out. 2) Hard shift from 1>2 - I think I have a solution for this figured out. Hard for me to test since only a couple people have this problem, but I think it's easy enough to solve. Then for my own installations, there are many ways to cook an egg, and I have been spending time trying different variations in excel. Would allow me to easily do two things: 1) Make softer versions for the Stage 2 and <20G clients as they request, and 2) Copy paste into the 08-09 platform. Full VB mod-and-swaps are very labor/time intensive when you do a lot for trial and error, so I've been good about testing on paper before spending the better part of a day doing all the things required to test a revision.

^ ain't that something

I don't know about the V6 springs, but there was an issue on LS1tech.com where people were having lots of trouble when Comp switched to a cheaper manufacturer of springs, at the expense of reliability.

Still working, no alpha product yet

Worked on valve bodies continuously from 8pm to 6am. That was intense... I've never worked on anything so complicated in my life... it's chaos... could only have been designed by a computer program... A very brilliant computer program...

Spent the whole evening working on valve bodies. I'm supposed to be modding 3 (2 F1 Cores and a regular F1), which I am doing. But I also went nuts on a tangent re-analyzing a lot of internal parts, and I found a few ways to revise the F1 product. VERY EXCITED TO TEST THESE NEW IDEAS OUT!!! I also figured out a solution to the 1>2 clunk for the few who have it. Again, just need to test it. I haven't been this excited about valve bodies in a while, but this could be exactly what I need to jump ahead with the 08-09s.

I'm not calling a business to waste company time until I have $10k in the bank allotted for burning, but will certainly keep that in mind.

What's your next car(s)?

With GTO oil pan there is no advantage to going dry sump unless you're going to do some serious track racing. Even then...