Hewland NLT or RBT ZF??

Bernard Seeker · 11-03-06, 05:20 AM

Hi Guys, Greetings from the land down under.

Been a long time observer of the forum, and decided to pop in and ask for some expert opinions.

just a little bit about myself, I recently aquired a roaring forty project car from a gentleman, the thing was basically a roller gathering dust in his shed. Since i've aquired it, i've striped it, the body is in a local shop for some re-alignment work (The Quanlity wasn't as good as i throught), and is thinking of pulling the moulds off it, since its currently out of business, and replacement parts might be hard to find. I want the GT40 to have relatively modern interior like the new GTs, a 6 speed manual and mostly for street use, with occasional track time with the local ford boys. I'm planning to use a DOHC V8 which is we have in new Aussie Fords, power output would be close to the 600hp at the crank, and they are quite easily to be sourced. The problem is of course transmission. I've measured the chassis and the body, ideally the length from the axle point to the end should not be longer than 17.5 inches to keep the best look. but most transaxles are 18.5 to 20 inches!

Alternatives I've found are

RBT ZF 6 speed, rounds about $9000 USD, relatively smaller compare to others, great for street use, tho clutch and other parts don't come from RBT, but somewhere else i believe.

Quifie Q-tek, too long IMO, 18.5inches, and expensive too, 7000 pounds, plus clutch kits, etc.

Hewland NMT, great dimension, 15 inches,would keep the great look, but its dog box, would be very very very noisy as some members have mentioned. its recommanded only to 320ft torque, which is far from the output of the V8's 500ft. and its 15000 pound

Hewland NLT, bit longer, 17.7 inches, same thing, dog box. appearntly Hewland don't recommand it for street use because clutch kits are hard to source. Is that a problem for forum members who have dog box installed in the cars? And one of the thing i'm really interested to know is what is the real difference between a full syncro box and a dog box besides its noisy, i'd imagine it'd have bit of problem keep a gentle smooth take off on a hill?

Well Guys, sorry for me writing so long, but I really need to plan out what to do with certain things. If you guys can give me some suggestions that'd be great. Or perhaps gearboxes i've missed to look at.

The max budgest I will spend on the transaxle including clutch, etc etc is around the $30k USD.

Russ Noble · 11-03-06, 05:51 AM

Jeez Bernard,

US$30k is where I'm expecting my entire car to end up! Nevertheless with that sort of money go for a Hewland LG600. It'll take the torque and it's a dogbox. Dogboxes are the opposite to syncro's they have to be shifted hard and fast. No different to take off with though (given the same 1st gear ratio) that's more a function of the clutch. Do a search on LG600 on this forum.

Good luck

Lynn · 11-03-06, 11:14 AM

Bernard,

Ever double clutch a lorry on the down shift?? That's a dog box. So, if you are a good heel-toer and have an ear for RPM matching then you're cool if you're cool with the sound level. I kind of like the sound of a dog box (like a really loud turbo), but I think it might get old in a street car. Ross is spot on with his LG600 recommendation to my knowledge.

If you want to go more civilized, I don't think you can do much better than the updated RBTs. And for the money, I am sure you can't touch them.

IMHO,
Lynn

Russ Noble · 11-03-06, 12:09 PM

Actually Lynn, with this type of dogbox you don't double declutch at all, you just ram it through with no clutch. Hard and fast. The only time you need to use the clutch is for getting off the line. See this from the horses mouth.
Hewland Help
Cheers

Joe T · 11-03-06, 12:41 PM

With your budget it may be worth looking at some of these :::::::::::::::::::: Xtrac - Motorsport Transmissions ::::::::::::::::::::

Cheers

Keith Hardy · 11-03-06, 02:31 PM

Wow - just checked their site. I knew Mike Endean (of Xtrac) briefly in the early '80's. I'm not sure but he may have come from Hewland but anyway, he did an amazing job straightening a shortened axle (for a 12 bolt Chevy) which everyone else said couldn't be done as it was treated (heat?) in the shortening exercise. Perfect job.

From small acorns! Sorry for the thread drift but from my early experience of the head honcho, I'd say that this company was definitely worth a look...

Sandy · 11-03-06, 04:56 PM

I was looking down some of the same paths for the RCR. I called and got pricing for the NLT. It was as I recal $26k USD for alumuminum case. Do a seach on NLT it should pop up. The NLT has to be ordered with your specified input shaft length and you will also have to come up with a bell housing if a ford (chevy's seem to be more available)

I think LG500/LG600's are around used in the 10-15k range. I was looking at one from a chevy that was about $11k usd. Still need the hewland ford bell or have to have one made (not too big a deal).

I ended up just going with a Porsche 930 that was prepped, the entire package with with clutches bell, etc was about the same cost as just the LG500 I was looking at. Large choice of clutches, easy to get bell and adapter. Seems to be one of the stroger boxes made, good gear ratios, and service does not seem that difficult if it arises.

Fran ended up convincing me that it was a good way to go and I think it is. About the only issue for some is that it is a 4 speed box. I ended up spending the $$$ saved in getting an NLT on an better motor as well as a spare gearbox.

Do some search on some of the older threads and you will find alot of the same discussion

Sandy

Bernard Seeker · 11-03-06, 08:16 PM

Thanks for the replies guys. really apprecited

I've sent an email to Xtrac for some prices and technical drawings. I think the biggest issue is the size and as well as being able to drive around the tight streets around town. Although the car will spend some time around the track too. No place to use all these horse besides the track.

One of the thing is ideally it'd have a 6 speed, provided that my budget isn't small. I'm seriously looking into the RBT 6 speeds, if required, i'll even go to the US to have a look myself. Any one has one of them installed and have a photo or something?

Cheers guys.

Lynn · 11-06-06, 09:48 AM

Bernard,

Call Lloyd Butfoy to confirm this, but, AFAIK, there is no difference externally in the RBT transaxles, 5 or 6 spd, from a good ole ZF 5DS 25. Following is a photo of one in a Pantera (Lloyd's actually), which would seem to support my contention:

BTW, Gear Ratios for the RBT-6:
3.7 Ring and pinion
1st gear: 2.86
2nd gear: 2.06
3rd gear: 1.47
4th gear: 1.18
5th gear: 0.958
6th gear: 0.704 (Opt: 0.642)

Regards,
Lynn

Sandy · 11-06-06, 10:54 AM

I thought the 6 speed ZF was bit longer, as I recall you have to do a bit of cutting in the pantera to make it fit to clear something in the rear (xmember, not sure)

I just got my backup 930 box from PowerhausII (saturday), and it looks way beefy, more so then the ZF, but alas it is only a 4 speed.

Sandy

Lynn · 11-06-06, 11:01 AM

Here is what the RBT 6 looked like in my little RPM/Speed Tool (attached):

Canuk40 · 11-07-06, 11:38 AM

Hi Bernard,

Go with the ZF, good enough to win Le Mans twice, good enough for the Salleen S7, Shelby Series 1, good enough for original spec, good enough for me. Attached is a pic of the ZF/RBT6speed we're putting in a customer car. It's about 55.4mm longer than the 5sp and comes with a reverse switch and speedo drive. Clutches, Bellhousings and Throwout Bearings are no problem.

Cheers

Sandy · 11-07-06, 01:34 PM

Quote:

Originally Posted by Canuk40

Hi Bernard,

Go with the ZF, good enough to win Le Mans twice, good enough for the Salleen S7, Shelby Series 1, good enough for original spec, good enough for me. Attached is a pic of the ZF/RBT6speed we're putting in a customer car. It's about 55.4mm longer than the 5sp and comes with a reverse switch and speedo drive. Clutches, Bellhousings and Throwout Bearings are no problem.

Cheers

I don't buy that discussion at all. The ZF is an excellent and strong box, not at all in question, but the Lemans small blocks didn't make anywhere near the power/tq that we are making today, given that Bernard is likely to make 500-600hp with his combo, you can't compare that to a 60's 289, and the race S7's that I have seen on the track are running XTRAC's not ZF's (Don't know about the Series one).

Again, the ZF is a very good gear box, but looking at it because of historical reasons is not the only factor that should be concidered.

Sandy

DBLDREW · 11-07-06, 02:44 PM

I’m not sure it will fit but consedering your budget and your running a mod motor why not look into the Ford GT transaxle it will easily handle your power…

Ford Racing Performance Parts [M-7003-GT*]

Bernard Seeker · 11-07-06, 06:37 PM

Quote:

Originally Posted by Canuk40

It's about 55.4mm longer than the 5sp and comes with a reverse switch and speedo drive.

Thanks for everyone's response. Ian, is it possible for you to do a measurement if you're free to confirm the length between the axle point to the end?

Still waiting for the reply from Xtrac. But the RBT looks good.

I had a look at the FordGT transaxle, it looks smaller than a ZF, yet the dimension spec was 31' in length.

Cheers guys.

Bernard

Sandy · 11-07-06, 08:45 PM

Bernard -

Look around on another thread for the Ford GT Box, I think they are too big to fit, and very heavy compared to the ZF. Strong, but I think for most GT40s way too large, but if you could make it fit would be strong gear box, and I think list price $13k as I recall. Also if you are going the ZF route best to give a call as one of other threads (Superformance I think) was mentioning they were going to be some time before they could fill all the orders.

Sandy