Built 7AT or ZF8 Conversion

shadow85

It's time for me to address my sluggish feeling 7AT, so either building the 7AT, or going all out for a full ZF 8HP transmission swap!

These days DCT and ZF swaps are becoming more and more common on many platforms due to the availability of good standalone transmission controller support and adaptor kits for them. So I have been heavily researching into and getting interested in doing a ZF 8HP75 (2nd gen) swap into my TT Z. Seb of SpecialtyZ has done a Getrag BMW DCT conversion on his own Z with great success from what I hear. A couple of guys in Europe have done this kind of thing aswell, some have done the DCT swap and some have done a ZF swap on their 370Z with success over in Europe. So it's definitely possible. However after adding up the costs involved, trans itself, adaptor kits, mounts, driveshafts, shifter, yokes, controller, plus controller wiring etc etc, I will be looking very well near at or over $15K AUD to do. That will be over or close to 2x the price of what it will cost me to build the 7AT down here in Australia ($7K AUD) with upgraded Valve Body and TQ converter.

So my real question is, how does a built 7AT with upgraded VB feel and perform in terms of responsiveness and shift speeds? Does it feel smooth and fast, is it much better than a stock 7AT? Because my current 7AT feel like a dinosaur, sluggish, old, and slow to reapond. So I want to either build it, or fancy the idea of a ZF8 (2nd gen) swap, the former will save me alot of coin, the latter would cost nearly double, but would be very cool and still super unique.

So what do you guys think? Be bald and daring and go for a ZF swap, or will a fully built 7AT perform just as fast?

rspray2000

What are your goals? I’ve seen claims of the VR30 swapped trans holding 570 ftlbs (likely 700hp) and it is likely much less expensive than a true built 7AT or DCT.

shadow85

Currently I am 500whp and 520nm torque. But I will eventually increase to 800whp+.

I want to be more future proof, VR30 will probably not hold more than 600 torque?

And I was mainly looking at a ZF8 swap, not DCT. I hear these new ZF8s (2nd and 3rd gen) are as quick as a DCT in shifts speeds.

14Q60awdSPORT

A stock VR30 trans will hold 500wtq, people have made upwards of 600wtq temporarily. But about 500-520wtq is the limits of hoping for some reliability.

A proper built VR30 trans though, can handle 750wtq.

wtq in Ft lbs not nm.

shadow85

520tq is about 700nm.

If I build motor, and can hit close to 700nm, then I will be on the limit of the VR30 trans and need to build it. By the time I do all that, the costs would be close to doing a ZF870/75 swap I rekon which can handle 700/750nm torque, but also most likely be faster than the VR30 trans. So I think I would go with the ZF8 then the VR30

14Q60awdSPORT

If it’s the same price or close to it, go for the ZF.

However you said above 15k for ZF and 7k for built trans. A built VR30 trans is the same price as a VQ trans. Only add in a little more to shorten your driveshaft for the swap.

The stock VR30 can handle and hold 520tq/705nm just fine, many people have been daily driving 540tq/730nm no problem. It comes down to how it’s driven, and how long it’ll hold up. Say it lasts 35-40k miles then you swap in a new stock trans for about $1200-1500.

I got a FI flexplate, and sent my valve body and torque converter to IPT to upgrade those for about $1,500. And a 19’ 30k mile VR30 trans w transfer case (awd g37) for $1500. This combo should be very good at 520tq/705nm.

Then if my clutch packs ever start to go out down the road I’ll buy the upgrade clutch packs drop my trans off at a reputable local shop and get the clutch packs installed. If the shop isn’t pulling/installing the trans you can probably get clutch packs + install for under 2k usd. Or I could just swap another stock VR trans and transfer over the built VB and TC.

phunk

I have a ZF8 HP in my brand new BMW X3MC and it does not shift anywhere even near the DCT.. not by a long shot. Still drives like an auto and you feel the delay and power drop during shifts. I am sure a built VR30 7AT can shift as well, or id be surprised if it couldnt. Since you are not looking to DIY any small part of your trans project, IMHO the built 7AT would be the most seamless for you. If you do a full trans conversion in your car, and do it totally hands off just writing checks, I would predict a nightmare to ensue any time there is an issue or glitch, as your car will forever depend on 1 or 2 specific people in the world to keep it on the road. When you have such a rare one-off combo, only the people who built it will be of much use to you. You could not just take it to another shop or hire a new tuner etc. If you dont want to take the bull by the horns, Id go less dramatic than any major conversion. I will give you that the ZF8, while still feeling like an auto, definitely feels like a very refined auto. Nice trans, though I am sure a majority of that refinement will be lost with the factory TCM development getting tossed aside for a standalone controller.

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shadow85

Interesting you say that, because I keep hearing the ZF8s are nearly as fast as DCTs now, maybe they are talking about the 3rd gen ZF8s? (Supra, ZR)
There is a few articles online about this?
Even BMW ditched the DCT for a ZF8 in their new M Competition cars.

Anyways, I still haven't ruled out a DCT swap either.

As for the refinement, I was under the impression that standalone controllers can make the transmission perform better?

phunk

Ya it is very noticeably still not as fast as the DCT. They are quick, but not in the same realm. The ZF8 is still a standard automatic transmission and it must actually physically change gears. A DCT trans already has the next gear preselected and when you "shift" it merely has to swap clutch pressures. I have the latest greatest ZF8 HP in my M Competition car, and it just isnt in the same ballpark as a DCT. I can understand why people enjoy it, but they are definitely over hyping it a little. A full throttle DCT shift, you cannot even really feel any time pass, it is as instant as your senses can perceive. With the ZF8 there is a momentary drop in power, you hear the classic "fart" sound from the shift-cut as it switches to the next gear, and then power comes back on. Nothing instant about it.

I would figure that its obvious BMW switched to the ZF8 for cost and for AWD. As the Getrag DCT does not support AWD. With each M car that transitioned to the ZF8, it happened in unison with the switch to all-wheel-drive. And to use the same base transmission in all their cars is of course very cost effective versus putting a unique and expensive DCT in just one small volume version of each model.

I think you will be best off with the VR30 7AT. From what I have seen the Q60s from AMS doing lately, it looks and sounds like they are shifting every bit as quickly as the ZF8 can. The big conversions IMHO are not going to be ideal for people who are after PnP "set-it and forget-it" packages. If you cant maintain it or make TCM updates and adjustments as needed, youll probably going to hate it. Consider that if with the 7AT, its still all controlled through ECUTEK and you can work with any tuner you want at any time, diagnostics will remain relatively OEM, and you can afford to go through a handful of them for the price of a conversion.

Standalone controllers can make the transmission perform more aggressively than the OEM TCMs are tuned. But not more refined. When switching from OEM controls of an engine or transmission and going to full standalone, you are starting from scratch, and ditching all the OEM R&D in refinement. Can you eventually make it as refined? Ya sure, if you put in the hours $$$$$$$$ and assuming the standalone software is as capable.

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shadow85

OK so with some more input and user reviews from various sources, I have narrowed it down to either the

1. ZF8 swap, or
2. VR30 built trans swap.

Reason for my choice,
Lots of the people who have experienced both the BMW DCT and ZF8, a majority of them concluded that the shift speed between the ZF8 and the DCT is almost negligible. The ZF8 is preferable because has smoother delivery, and easier to maintain and build. And doing the wiring for a ZF8 swap is apparently far easier than doing wiring for a DCT swap, the latter requiring alot more work according to DomiWorks, who do these swaps on a regular basis. They also stated, that wrong calibration on the ZF8 is far more forgiving, because the TQ converter can take abuse and they are cheap to replace. They said that wrong calibration on a DCT will quickly fry clutches and they are very expensive to repair.

But, I have also been looking into the VR30 Transmissions and actually pretty impressed with what they can offer to, as 'phunk' pointed out, it would also be less of a head ache for me to switch too aswell compared to a ZF8 swap.

FrankEtier

I just put a VR30 7AT in my 370Z. Got about 200 miles on it since the swap. So far I'm happy with it. Super easy swap, almost plug and play... My VR30 transmission is completely stock from a 4k mile Q50. I have the fast intentions billet flex plate and a external transmission cooler. May look into internal upgrades on the VR30 transmission later on if I feel it is lacking or if it gives me any issues.

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‘14 Topgunz Speedworks Rotrex Supercharged VR30 7AT 370Z Magma Red.
@liquid.magma

THE BULL

That's a huge price difference in just wanting a faster responding transmission.

The sad reality is that most likely that same feeling will persist with the VR trans.

You cannot beat having another gear plus proven work from the DCT. If you're planning on 800whp and plans on constantly utilizing your best bet is to invest in the expense of the BMW because the VR is still being discovered.

The issue here is ONLY VHR owners will be able to prove how much torque it will actually hold. The added displacement with the VHR means it will see boat loads of torque more than the VR at the same HP.

Tractionless

Maybe Jchammond will chime in about his built IPT trans. impressions.

In the meantime have you made any adjustments with the throttle sensitivity and torque demand charts in the tune? This greatly improves shift speed.

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Toys Not Tots

Spooler

He has to get his car up and running first. Maybe the end of the year or next year the way he is going.

sx moneypit