Two words: shift quality. The 8HP transmission from German supplier ZF is and graceful enough, and it combines those elements of speed and smoothness whether it’s installed in an Aston Martin, a Rolls-Royce, or a Jeep.Albert Dick, vice president of car powertrain technology at ZF, says the 8HP’s deeply satisfying shifts are rooted in factors ranging from the quality of the solenoids to the manufacturing methods to the control software.
They’re also a product of a fundamental design that determines how the four planetary gearsets, three clutches, and two brakes in every 8HP gearbox are parsed into eight forward ratios. All one-gear and two-gear shifts use just two shifting elements: one opens, another closes. The 8HP also executes certain multigear shifts in this manner; witness the leaps from sixth gear to third and even eighth to second.The 8HP transmission comes only in longitudinal form for rear- or all-wheel-drive vehicles, and we prefer it immensely to ZF's. In 2017, some 3.5 million 8HP transmissions were built for a laundry list of manufacturers that includes Aston Martin, BMW, Fiat Chrysler, Jaguar Land Rover, and the Volkswagen Group. Beyond performance, the eight-speed’s appeal is rooted in its versatile modular design. It can accommodate a maximum torque output from as low as 162 pound-feet up to 770.
It is compatible with a variety of all- and four-wheel-drive systems, such as an integrated center differential or a two-speed transfer case. The ability to swap the torque converter for an electric motor, allows automakers to develop hybrid variants with minimal changes to the drivetrain.
And the commonalities among all 8HP gearboxes allow companies to share core elements between vehicles as different as and, minimizing development costs. “We keep the same power flow through all of those applications, so we can carry over the calibrations, the software, all of those tools that keep that transmission shifting smoothly,” says Eric Burnett, chief engineer for eight-speed, rear-wheel-drive transmissions at Fiat Chrysler.Has the dual-clutch transmission met its match, then? You might think that’s the case, given the recent and, which switched from dual-clutch transmissions to ZF’s 8HP torque-converter automatics. That’s also the opinion of Andy Palmer, CEO of Aston Martin, who claims ZF’s 8HP is lighter, cheaper, and quicker than a dual-clutch transmission. “Ten years ago, the dual-clutch still looked like the transmission of the future. Now it is starting to look like the transmission of the past,” he tells us.
But the DCT finds refuge in supercars. The added length of a torque converter can be prohibitive in a mid-engine architecture, and precise launch-control programs provide an advantage in acceleration. And engineers maintain that a good dual-clutch ’box does shift quicker. “For our kind of product, it’s about a really fast shift, which the pre-engagement element of a dual-clutch gearbox helps us with.
We think that’s still got a decent speed advantage,” says Marcus Waite, chief engineer of the McLaren Senna.But for just about every other vehicle, though, it's hard to argue that anything can do the job better than the ZF eight-speed.
Hi Folks,On paper, or in video more accurately, this is one thoroughly impressive looking transmission:At 200 lb wet w/ converter, it weighs about 55 lb less than a comparable 4L80E. It has about 740 ft-lb rated torque capacity, and operates at typically 98% efficiency. Overall ratio spread is 7:1, and shifts occur faster than human reaction time could achieve. It's the transmission being used in the new 700hp Dodge Hellcat package.That said, I have no idea whether it could be adapted to our cars, or how much it would cost, or how one would electronically control it (details, details.)Does anyone have further knowledge?Thanks,MAP. Heck, I wish I could get it in my 2008 Charger.I could do without the 4.xx first gear but the double overdrive would be nicer than the NAG1 5 speed with a.83 overdrive that I have now.The mechanics of it can be done but the electronics might be the hard to resolve. I am told there are only 4 wires going to the trans and the controller is inside(based on info from the 8HP45 Chrysler uses) Two of the wires are power and ground.
The signal from the shifter is sent via dedicated CAN Bus.You won’t find the transmission module under the hood or combined with the powertrain control module like most Chrysler vehicles. Instead, the module is located completely inside the transmission and is comprised of the control module, speed sensors, temperature sensor, park position sensor and solenoids. Chrysler calls this its Transmission Control Module Assembly (TCMA).There are 13 manufacturers that currently use a version of the ZF 8 speed(dodge, Chrysler, Jeep, Ram trucks counted separately).
Hi Gruvin,Thanks for that information. Interesting how transmission swaps are increasingly dominated by electronic/control issues rather than mechanical ones. I wish the aftermarket would focus much more on this area, rather than staying fixated on using the brute-force technique of making the internals from stronger materials and increasing the number of clutch plates.I'm not saying that that's not worthwhile, but it is conceptually limited. That's why, for example, I think aftermarket adaptations of the 200R4 and the 700R4/4L60E designs have gotten as robust as they will every get, so the next step up must be a different platform.Have you heard of anyone trying an 8HP. swap into anything other than a stock vehicle?Again, on paper, the ZF 8HP90 is one thoroughly impressive transmission.
And, its torque rating of 740 ft-lb suggests that torque management of the motor during shifts isn't part of the control scheme, which in turn should make the design favorable for aftermarket adaptation.Best,MAP. Hi Folks,I learned about this transmission literally days ago, but it turns out the concept was rolled-out about four years ago by ZF.Here is a short article from Car and Driver about this design:Again, curious if anyone has heard about hotrodding with this transmission. In every respect, again at least on paper, it runs circles around the 4L80E: the ZF is lighter, stronger, and more efficient. And, by the way, it has 8 speeds vs. 4 with the 4L80E, and a top:bottom ratio spread of 7:1 vs. The 80E's relatively paltry 3.3:1.Best,MAP.
Zf5 Transmission For Sale Craigslist
Hi Gruvin,Thanks for that information. Interesting how transmission swaps are increasingly dominated by electronic/control issues rather than mechanical ones. I wish the aftermarket would focus much more on this area, rather than staying fixated on using the brute-force technique of making the internals from stronger materials and increasing the number of clutch plates.I'm not saying that that's not worthwhile, but it is conceptually limited.
That's why, for example, I think aftermarket adaptations of the 200R4 and the 700R4/4L60E designs have gotten as robust as they will every get, so the next step up must be a different platform.Have you heard of anyone trying an 8HP. swap into anything other than a stock vehicle?Again, on paper, the ZF 8HP90 is one thoroughly impressive transmission. And, its torque rating of 740 ft-lb suggests that torque management of the motor during shifts isn't part of the control scheme, which in turn should make the design favorable for aftermarket adaptation.Best,MAPit's 740 ft lb rating is because of torque management from the trans module, backing off the pressure to clutch packs allowing some slip, unlocking the ttc at high rpm shifts, the trans will know the engine rpm and slope of increase by the gear it's in, and the units rpmif you put 740 ft lb to it at a wot shift it park it's guts all over the road. There is a reason Allison trans are huge.
And this one isn't, it's the control box that makes sure the parts never see a 740ftlb shock load EVER I doubt it ever see a 500 ft lb shock load. Running ft lb through it and shocking it with full power shifts are not the same. Rear ends that died behind 330 ft lb are now able to take 500-600-700+, think about it. Metal stamping that got stress cracks from half the ft lb of this hellcat, now can hold the rear end in place.
Either the metal is now coming from nasa or, the driveline never see's that 740ft lb until 1 to 1 gearing, nevermind shearing the bolts off the crank flange, and wheel studs, u joints, spider gears, axles. The housing itself. The engine and trans mounts, an honest 740ft lb shock load would push the diff right out of the housing. Hi Eric,I'm a bit confused - are you saying that the ZF 8HP90 can handle a motor that can produce as much as 740lb-ft by dialing-back engine throttle electronically during shifts, or that the transmission itself can handle that much torque? My guess is that it's the latter based on the what most of the industry seems to be reporting. I wouldn't presume that with some ingeneuous design engineering, a transmission that's smaller and lighter than the 4L80E couldn't handle as much torque or possibly even more, without having to resort to torque management.Also, there's news that GM is working on a ten-speed, but this is only slightly encouraging news, because the gap in offerings between the aftermarket and the OEM in the realm of transmissions is growing wider and wider. Even GM performance parts, for example, is stuck at four speeds.Nowadays, sadly, we're increasingly having to buy the entire drivetrain out of a car if we want the latest and greatest.
That's why I'm hoping that the ZF torque rating is a true maximum input rating, and not some dialed-back engine output rating. That way we stand a much better chance of getting the transmission hotrodded in the aftermarket provided the control scheme isn't too complex.Best,MAP. Most any trans can run 740 ft lb through it. As long as the output shaft isn't stalled.it's the shock loads at up and down shifts.and why I'll bet that internal trans controller cuts down the shock load buy slipping the clutches and a slower engagement rate till fully locked, and torque converter clutch is unlocked so there is slippage there also. Taking that 740 ft lb and cushioning the twisting force think of the set up in the same vein as John forces funny car, they can't get 7000 hp to the ground so they take the shock out of it slipping the clutch.
That trans module is doing the same thing, dropping the torque load the parts are seeing using the clutches an consumables to do it. And the fluid coupling needs to rebuild when the tcc is unlocked, eating ft lb as it builds up. Cushioning the shock load even more. Driveshaft companies have shaft dyno's I'd like to see the input to output shaft locked together by way of the trans clutches in 1st/2nd/3rd/4th/etc my square is on something letting go before the needle crosses 500 ft lb.
In a shock load test. And before 600 slowly bringing the torque on, never mind in o/d with the internals try'n to pass through the cases mid support, the materials used and there size just won't take that type force. As I doubt mother mopar opps zf is using mil. Billet/etc to make the parts, or the case.anyone know the input and output shaft spline count and size??and material thickness of the input one, as it's hollow the flexplate still mild steel? 740 ft lb would egg shape the converter bolt holes in no time. Never mind sheer off those 3/8th (10mm?) bolts. Don't assume that closing the throttle and retarding the timing during the up shift is for torque management.
The input shaft speed needs to slow by 1/5 to 1/3. Using the engine to rev match makes the shift faster. This is what is allowing the lightning fast shifts. Using the clutch pack to drag the full power engine down creates a lot of heat and takes time. Without drive by wire, shift times will increase and the clutch to clutch shift timing is tougher.Using this trans for aftermarket apps is going to be difficult. The computer expects certain things and will likely require a software rewrite not just a recal.
You can remove the computer by tapping into the sensors and solenoids with a different computer. To accomplish this you would need to replicate all the functions of a TCM. It is not as simple as for this TPS and speed select this gear. The TCM control shift pressure and clutch to clutch timing. It has to calculate or know engine torque and rotational inertia so that the shift pressure and timing can be calculated. I don't think we will see this aftermarket.John- 08/16/14 06:51 PM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: May 2002Posts: 3,92015+ Year15+ YearMemberJoined: May 2002Posts: 3,920.
Hi John,I don't see how engine controls could quickly reduce engine rpm's for rev-matching under am upshifting regime. Ultimately engine pumping losses do this passively. Accomplishing 1/5-1/3 ish fractional reduction in engine speed in less than 200ms would require a higher retarding torque than I think pumping losses alone could accomplish.But aside from this, if what you wrote is true, then the aftermarket hotrodding industry will see a greater and greater disadvantage as time passes relative to the OEM for creating drivetrains with very high output, very high reliability, and reasonable economy.In fact, I think it could almost be said that the handwriting is on the wall.
My guess is that not more than 20-30 years out, hotrodding will be essentially dead, save for a tiny niche group that drives their vehicles a 1/4-mle at a time, or that transplants drivetrains from current OE vehicles whole into older chassis.Thanks, (I think?!)MAP. Hi John,I don't see how engine controls could quickly reduce engine rpm's for rev-matching under am upshifting regime. Ultimately engine pumping losses do this passively. Accomplishing 1/5-1/3 ish fractional reduction in engine speed in less than 200ms would require a higher retarding torque than I think pumping losses alone could accomplish.But aside from this, if what you wrote is true, then the aftermarket hotrodding industry will see a greater and greater disadvantage as time passes relative to the OEM for creating drivetrains with very high output, very high reliability, and reasonable economy.In fact, I think it could almost be said that the handwriting is on the wall. My guess is that not more than 20-30 years out, hotrodding will be essentially dead, save for a tiny niche group that drives their vehicles a 1/4-mle at a time, or that transplants drivetrains from current OE vehicles whole into older chassis.Thanks, (I think?!)MAPyou are totally wrong.what we are seeing right here right now, is THE END OF THE 2ND HORSEPOWER WARSyou are forgetting that the new epa and c.a.f.e standards will be bringing an end to large c.i.d. V8 cars for the reg joe, the big v8's will be limited to a very few high end cars.
No more mustang gt large v8's it'll be the cobra model that's 80k+ same with the Camaro's, it'll be the z-28 at 80k+, mopar will be the viper at 100K +, the craziness is about to have the door slammed in it's face. And why next year you can get a mustang turbo 4, the hot rodders won't be at a disadvantage because there will be millions of ls v8's, hemis and fords don't call me a mod motor v8's to go around for another 50 years, while the oem's won't be allowed to build many crazy hp cars, and they will be priced accordingly. As ford/gm/mopar make to much money off trucks and will need to keep v8 fuel hogs in them, but I can see 1/2 tons loosing v8's from the option sheet and going to baby diesels if you need to tow.- 08/16/14 09:47 PM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: Mar 2012Posts: 310MemberMemberJoined: Mar 2012Posts: 310. Besides someone that builds aftermarket efi's will take and start making stand alone controllers for all that oem stuff.limited use ones like this zf, I doubt it, but 8-10 speeds that are put in tons of vehicles, they will.
But to keep that ft lb rating the engine it's bolted to will have to have an ign timing chart/map that pulls power out at shifts, and be triggered by the trans module.(I'm shifting)to do so. Instead of the efi ecu having a 2nd map for n.o.s.
It'll be the shifting map.the MSIII more than likely can do it now. Just need a trigger to tell it when to switch to those maps/tables.- 08/18/14 12:11 AM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: May 2002Posts: 3,92015+ Year15+ YearMemberJoined: May 2002Posts: 3,920. Hi Eric,Interesting, but I don't think the new EPA rules will stand for very long. And as for the aftermarket, so far they have shown great ability to improve robustness mechanically, but their ability (or is it willingness?) to do so on the electronic side has been very limited. Let's hope they make big strides in software control.
Honestly, I don't think they will, because gearheads and control system experts/IT whizzes tend to be two very different kinds of person.Another factor that may increasingly enter the mix is electrical drivetrains. Battery energy density storage capacity is always increasing, but once again, only the OEM seems to be in a position to take advantage.Thanks,MAP.
The aftermarket side.well that's not really true. It's out there. Now.but the problem is hot rooders for the most part don't want to have to relearn everything, and why many have a carb on them, it's the K.I.S.S. And they have good reasons.1) the electronics and not cheap take efi.
Real efi not TBI. Holley wants 2700.00 for the bolt it on mpefi. If you can add injector bungs to your carb intake it's 1700.00 both have no injectors or fuel pumps. As they are a app by app part.even if you buy a new holley carb, say a 750 d/p or vac 2md it's 4-600.oo and carb intakes can be had for 50 bucks.2) this electric wonder land requires A) a full function scanner, to test the system when issues pop up, when you use an OEM based system, like the ls ecu/etc or this trans. B) the willingness to the oem to open up there info to the aftermarket. And we know the indy shops can't get the same info the dealers do. The aftermarket is the same way.The other biggie that really kills most of the new wonders from the oem is the fact that the aftermarket would be working on small volume, and that makes say a stand alone controller box for this trans to work in a non oem setting very pricey.today, right now, you can get a4l80e, a '96 diesel 4l80e controller(or aftermarket one that can be programed ), a gearvendors and have 8 speeds.
And it'll cost you about 5000.oo +/- 1000.ooit being all in one case is ideal. And because it's not an OEM part it's a ZF that supplies the oem. It could happen. But I'm willing to bet that, that zf is a 10000.oo+ trans.not to many gonna pony up for that even if it was avail.mopar guys have a better chance of see'n the ram trans used in rods than this one. And better chance of finding them in the junk yard.The 80-90's billet trend almost buried the rodding hobby. I'm sure someone with a lowly v8 with a turbo on the side and a 3 speed will show this thing it's tail lights. It's fast (iirc high 10's) but it's not that fast.
There are cars running 7's on the street right here right now. And tho that's the extreme end, there are tons of k.i.s.s. Cars running low 10's and 9's.
This trans isn't the tech that make or break the rodders, it'll be turbo's.and as far as the epa, hope you are right, but with them not accountable to the oval office or congress, I don't see that happening.now it's awesome that the oem's are building crap like this. I don't know about you. But I can't afford the sticker price,nevermind the dealership markup on stuff like this.and finding one wrapped around a tree in a yard to pillage the gear from isn't going to happen.the future is bright for rodders,gearheads but we'll have to be willing to relearn what we know. Efi and computers, turbo's and rpm. Torque management to allow parts to take that turbo'd 5.3 ls pawer.
It's all avail now. It's just the rodders of today don't really want any of that. They want their sick sounding, rip your neck off, stupid simple hobby vehicles.
The Honda crowd, now those are the ones that if and when they move to v8 rwd that will make even a 426 hemi look silly- 08/18/14 08:43 PM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: May 2002Posts: 3,92015+ Year15+ YearMemberJoined: May 2002Posts: 3,920. Hi Eric,Thanks for that. Not sure what to make of it all, but I suppose it comes down to the goal I stated before: 'very high output, very high reliability, and reasonable economy,' to which I would now add, 'reasonable weight,' is a combination that will be increasingly less likely to come from the aftermarket but rather from the OEM. Maybe the aftermarket can hit two out of those four goals, but three goals, much less so, let alone four.If we add a fifth goal of 'reasonable cost,' then the ship's taking on water fast and already down by the head.
So, my opinion is still that hotrodding is rapidly headed for the two fates I described five posts ago.Thanks,MAP- 08/18/14 10:50 PM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: Mar 2012Posts: 310MemberMemberJoined: Mar 2012Posts: 310. Problem is you are expecting things like economy.news flash a 700+ hp car oem or not will not have any 'economy' sure if you drive it like there is an egg under your foot you might get high teens low 20's hyway, but if you drive it like you bought it for that power, not a chance, it'll be bbc mpg numbersreliability, Ital red heads reliable?? Or is their upkeep cost huge. Anyone that doesn't park that hell car in a warehouse is in for the same big upkeep cost.your 5th goal. Well you're compairing parts in a 100k carif you expect to use stuff from cars like this in a hot rod it won't be cheap.
Here is my question, is it really NEEDED.a turbo'd 5.3 v8 with a th400 and a gearvenders will get better mpg, and most times out run it. Only thing this trans would add to a rod is the WOW factor. Nothing more. I expect it all, just as the OEM expects it all, because they're responding to a real market demand. Of course, economy is a relative thing. If I can get 10mpg in city driving with 700hp with a light foot, while an old-school mechanical-everything approach gets me only 6mpg, then I call 10mpg 'economy' in a relative but still valid sense.In the hotrodding world, come on - nothing is truly needed.
No one 'needs' 700hp. But we want it badly, and we don't want to mortgage our house to pay to keep the car in petrol. As to the comparison of the ZF 8HP90 with the THM400 + GV-OD, this couldn't be more ludicrous. These are worlds apart in efficiency, gear ratio spread, and even robustness (for the THM400.) Put the same motor in front of both transmission configurations with the same TC stall speed, and the ZF will be faster and get better economy by far. So just a 'wow' difference, which by the way counts for absolutely nothing with me, the ZF most certainly isn't.Anyway, I think we've exhausted the current direction of this thread, so as the OP, let's bring the topic back to the ZF.
If there's nothing further to add about the ZF transmission, then we'll let the thread coast to a stop here.Best,MAP. Well I'm done as you want it all and think it'll be with in reach of the normal working stiff.everyone wants it all, but can we afford it???today, you can build a 700+ hp engine and dump it in a car and smoke this hell cat. With a outdated pushrod v8 with a turbo bolted on. And get better mpg and drive it day in and day out without paying a kings ransom to the insurance company to do it.or you can buy a car off the showroom for 100k.
Or buy the zf trans and pay a guy to make it work.if you need 8 gears just for the sake of having it.for someone that wants it all, why you have a g body?? So the hijack stops.- 08/23/14 01:10 AM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: Jul 2002Posts: 93410+ Year10+ YearMemberJoined: Jul 2002Posts: 934. Hi John,I don't see how engine controls could quickly reduce engine rpm's for rev-matching under am upshifting regime. Ultimately engine pumping losses do this passively. Accomplishing 1/5-1/3 ish fractional reduction in engine speed in less than 200ms would require a higher retarding torque than I think pumping losses alone could accomplish.See patent 8721498 B2 for how GM is using throttle close and fuel cut out to reduce shift times. Patent 636811 B1 is also interesting.
It is the shift control description for 6L90 transmissions. It plus the cited patents pretty much describe the clutch to clutch. It will give you a feel for how the first clutch is released and the applying clutch goes through removing the inertia and reducing the RPM of the mass is front. But aside from this, if what you wrote is true, then the aftermarket hotrodding industry will see a greater and greater disadvantage as time passes relative to the OEM for creating drivetrains with very high output, very high reliability, and reasonable economy.In fact, I think it could almost be said that the handwriting is on the wall.
My guess is that not more than 20-30 years out, hotrodding will be essentially dead, save for a tiny niche group that drives their vehicles a 1/4-mle at a time, or that transplants drivetrains from current OE vehicles whole into older chassis.Thanks, (I think?!)MAPI think that the OEMs have always had much better R&D, knowledge and methods. The disadvantage of the OEMs is that most of the cars they build are not hot rods. The aftermarket will always be years behind. What the advance in technology is creating is a need for more R&D in the aftermarket. You can't just throw in a bigger cam anymore and be a superstar.
Zf 8 Speed Transmission For Sale By Owner
Places like Edelbrock are becoming real design houses.I don't have much on the ZF. Only what can be googled. I think it will be few years before we get lots of info.John- 08/25/14 08:32 PM Re: Anyone try the ZF 8HP90 8-speed automatic?Joined: May 2002Posts: 3,92015+ Year15+ YearMemberJoined: May 2002Posts: 3,920. Hi John,I'll check those patents - thanks.About your description of the OEM vs. The aftermarket, this is exactly my read too. And it's not encouraging for the aftermarket. The OEM, in general, is hiring PhD's at a far faster clip than the aftermarket is, and this divergence will probably grow with the passage of time.
But even if there magically were no difference in total R&D investment in the OEM vs. The aftermarket, the aftermarket, by virtue of its relatively tiny market share, would have to amortize its investment on a much smaller product volume, which means that the per-unit R&D overhead burden would be far higher than what it would be for the OEM. Translation: the cost of high-tech solutions from the aftermarket will outpace the cost of those same solutions coming from the OEM. And we're definitely seeing symptoms of this to a greater and greater extent with the passage of time.About engine braking during shifts, one idea that occurs to me is a small, secondary combustion event to create an opposing torque on the crankshaft during shifting, on the compression or exhaust stroke. Primary combustion would be disabled during this time.
Impact on emissions: completely unknown to me. But for a shift duration of only about 1/5 sec, the overall impact should be tiny.About the ZF transmission, apparently the 8HP.
has been used for about five years now, and as to price, I saw an 8HP. takeout on sale on eBay for $1.5k. Scanty data for sure, but it's something.Best,Mark.
Related Posts