We can improve our shift speeds with HP Tuners..
We can create launch control in our tunes with HP Tuners..
So what's the point of buying a shift kit or aftermarket torque converter these days
We can improve our shift speeds with HP Tuners..
We can create launch control in our tunes with HP Tuners..
So what's the point of buying a shift kit or aftermarket torque converter these days
You can't tune a stock converter to stall any higher, thus the need for aftermarket converters with high stall speeds when swapping camshafts.
Shift kits depending on brand and the way they work will physically allow for more fluid flow with valve body changes.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
But,
end of the day,
we can still make a 2-step launch-control "thing" with HPT so we can take off at say 4,000rpm..
and
we can quicken our shift times..
so (again) what's the point of spending 100's of dollars on a shift kit or aftermarket torque converter + doing all the work or getting a shop to do it for you + having your car off the road... if you own a tuning device which can improve your launch and shift times..?
If I edited my tune to quicken my shift speeds by 200% for example + hooked up a 4,000rpm 2-step.. what gains will I get if I spent $1,000 afterwards on a torque converter + shift kit?
5% quicker shifts and 7% better acceleration on WOT rolling starts/runs? Big deal.
Seems like a huge waste of money and time to me.
Shift speed isn't just about the opening or closing of a solenoid; it's also about the movement of the fluid in the trans via valves and springs in the valve body. Although you may be able to tell the electronics to behave in a certain way, they're still only as capable as the mechanical systems they're interacting with. Shift kits and converter changes are physical improvements to those mechanical systems; electrical fiddling simply doesn't (and can't) net the same changes you get from physical modifications to mechanical parts. No amount of fiddling will get you a stall speed higher than what the converter is capable of; if you need a higher stall, you need to change mechanical parts; if you need more lockup up top you'll also need mechanical changes. If you want the quickest, firmest shifts possible with the most line pressure possible, you'll again need mechanical changes.
5% and 7% gains are *HUGE* -- folks spend a *LOT* of money (multi-thousands) to get a 5-7% improvement in power...
2007 Z06 (E38 ECM), stock LS7 short block, .030" milled/ported heads, PLX SM-AFR, MPVI Pro
You can't tune any engine or trans beyond it's mechanical limits, it's as simple as that.
That's what shift kits, aftermarket torque converters and engine mods do, improve the mechanical abilities to increase performance. Then you use HPT to calibrate the computer for those changes since the factory tune isn't suitable for them and will not work to it's full potential until you tune it.
Tuning software is not like a valve that you open more and more every time to get more horses, it doesn't work that way. HPT is to calibrate fueling, timing, throttle, trans shift/pressure and everything the powertrain does to their most efficient settings so they deliver their full potencial. No tuning software or ECU in the world will give you more power than the engine/trans are able to deliver, period.
9 sec Montecarlo SS
Okay, thanks, guys.
1) 5 and 7% was just a rough example. I meant "f all" gains.Originally Posted by sillycon
2) I'm not talking about power + 4 second cars or 1000+hp dyno queens...extreme examples/cars. I mean your "average" 12 second car.. and shift speeds + launch...
3) Improving your shift speeds by 5% (like in my example) is nothing / f all anyways. It's not like it'll make your car 0.5 of a second quicker in the 1/4. More like 0.005 of a second.
Soo.. you're saying we can't increase our engines power by tuning it with HPT?
You're saying we can't take off at higher rpm's in our auto's by tuning it with HPT?
I believe that's what you're saying.. and is clearly wrong.
Like when you buy a car/engine and it claims to have 325hp from factory.. I'm pretty sure you can tune it with HPT and increase the power.
Can we improve/quicken our shift speeds with HPT alone? Yes or no?
Can we hook up a 2-step with HPT alone to improve/quicken our launch? Yes or no?
Last edited by Mr. Smith; 05-31-2017 at 03:48 AM.
I am pretty sure your missing the point here. Yes you can tune for more horsepower, yes you can improve the shifts, but you can only do it within the mechanical limits. You cant just setup a 2 step at 4000rpms with a stock converter, because mechanically it cannot stall to 4000. You will need a converter to achieve this. If you have a stock engine that makes 325 hp from the factory, yes you can increase that with hpt, but the gains are not going to be huge. To get large gains will require internal modifications to increase the engines volumetric efficiency. You cannot do that with software alone.
Shift kits also are soooooo much more than just pressure increases. They give you springs, and small components that are required with higher pressures, and higher rpms. Stock piston springs typically cannot sustain high rpm use, as well as valve body springs, cannot sustain high fluid pressures. Sure you can mimic a shift kit, but a tune isn't a replacement for a shift kit.
Trust me as someone who builds transmissions and tunes all day everyday, a transmission with properly calibrated transmission functions, coupled with a quality shift kit, will live a longer, happier life than one without a shift kit. Even as sophisticated as the 6 speeds are, they till benefit from a proper shift kit. I haven't seen anything for the 8's yet, but I'm sure its coming
Michael Bray
Rusty Knuckle Garage
Slidell, Louisiana
20yr Master Tech.
Advanced Level Specialist
Custom Car Fabrication, Customization, High Performance.
GM World Class Technician
Shop Owner
I totally agree that software programming can't change mechanical limitations. But I also see @Mr Smith's point - the fact that so much more of modern transmissions are electronically controlled, does mean we have more "tunability" and more control than ever before. Within the realm of moderate street cars, the software tuning alone can do today what back in my teenage years would have required a higher stall converter or shift kit.
As an example, it's stunningly impressive that in a modern trans like the GM 8L** series, we can control the point at when it shifts, how hard it shifts, how fast it shifts, when and how the TCC locks-up, main and gear-specific fluid pressure, etc etc. With nothing but some key strokes on a laptop, we can go from a transparent soft, low-rpm shift to a tire-chirping high-rpm race shift. To me, that's what I would have bought a shift kit for back in the TH350 days.
I hope this is a troll post. But if not:
No, no matter what you do in HP tuners, you CAN NOT increase the RPM in which the transmission engages and moves the car forward from a stop. This is a MECHANICAL function of the converter.
If you put a "2 step" at an RPM higher than when the converter mechanically engages, you simply wont be able to get to it.
Also, with truck and heavy duty automatc transmissions such as the 4L80, you cannot add enough line pressure or make it shift quick enough to truly engage hard or increase power holding as much as you'd like in a high performance application. You could, however, get it to shift "nice" AND shift hard, depending on throttle position and RPM, using the tools within HP, if you did a shift kit.
Last edited by Turbo_Mike; 05-31-2017 at 03:19 PM.
2003 305/555 QCSB Cummins
Piston/rod/sleeve/fire ring/dual CP3/300 overs
Super Stick NV5600
S366/S480
I'm not missing the point. I think you guys are. I'm not saying you can get your trans to perform like one from a 1 million dollar Ferrari hypercar by just tuning it with HPT....... and I'm not talking about huge gains............
I'm just saying; are they worth buying/doing if you own tuning software like HPT..... and aren't loaded.
Obviously, I know that there are mechanical limits.. there's only so much that you can do (with HPT).....
I never meant that HPT tune alone = equivalent or better than high stall + shift kit.....
.............
It's just the word "useless" in my title that's got some of you going*blasphemy!
There's only so many characters you can fit in a thread title.. and I didn't mean "useless".. more like "are they worth the money and effort...(for HPT owners.. who aren't millionaires...)?"
Exactly.
Why would it be a troll post? Something sound funny/stupid to you about the fact that we can improve our transmissions performance with HPTs alone (just like we can with our engines), so spending money on a shift kit + torque converter might not be worth it?
Regardless of how you meant to ask the question, the answer is still the same -- YES, they are worth the money if you want the features/benefits (outlined above) that they offer. Some folks would prefer to periodically replace clutch packs, some folks would prefer to change springs in the valvebody once and avoid fussing with clutch packs. It's up to the user/owner/driver to decide which path is most appropriate for them.
2007 Z06 (E38 ECM), stock LS7 short block, .030" milled/ported heads, PLX SM-AFR, MPVI Pro
The 4L80 was originally designed in 1990 and rolled out in '91/'92. It's a quarter century old design. Perhaps that's part of the disagreement/misunderstanding in this thread - some are talking about new trans and others are talking about old trans.
The new 8 and 10 speed GM/Ford co-op trans can shift as fast as the Porsche PDK. The 9T's can get close to that even in FWD configuration. They can indeed shift as hard as you can possibly want without changing anything mechanically. One click of the keyboard equals tire barking shifts. A second click of the keyboard equals transparent smooth shifts.
Granted it's true you can not change stall speed.
Well then we don't need wider tires either, just tune your traction control to match your tire size. Might make the car slow as shit but you'll never have traction problems.
The difference between winning and losing usually is parts selection and tuning, so do as you see fit and see how those ideas work for you.
Can we prevent high rpm centrifugal clutch apply with hptuners? NO
Can we time the second servo release to the third-fourth clutch apply with hptuners? NO
Can we prevent runaway line pressure from a worn boost valve (4L80E) from breaking the reverse servo with hptuners? NO
Can't we just take a trans with no friction material left and bump up the line pressure with hptuners?
Saying hptuners can make you launch at a higher rpm is as stupid as saying you can change rear gear ratios with hptuners.
You can footbrake your stock converter to a higher rpm because at some point the clutches in the transmission start to destroy themselves.
The Transgo 4L80 Kit has one nice feature which prevents the transmission from over pressurizing and blowing the side of the case out, they also conveniently have all the critical updates listed in their kits and other cool features like the multi-feed laminated valvebody plates to improve direct clutch apply and other things that improve durability. IE I agree with Jason !
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