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-   -   New drivetrain setup: VR6 (http://www.madabout-kitcars.com/forum/showthread.php?t=7225)

hondekop 6th January 2020 15:11

New drivetrain setup: VR6
 
Hi everyone,

After lots of consideration I have changed my drivetrain plans.
Currently my Deon is sporting a Cologne V6 & IB 5 gearbox. This was always bound to be thrown out in favour of a more modern engine (they don't call it the "iron pig" for nothing).

I thought long and hard about an Alfa V6 3.2L 24V, as well as a Jaguar V6 3.0L 24V. Both deliver about 240 HP stock and have aluminum engine blocks. However, when I measured up the engine bay, things became a lot less straightforward. Both engines may fit with some effort, but positioning is far from ideal due to lack of space. Below you can see both engines in the the engine bay:

The Alfa V6 is sitting too high and too far back, placing the driveshafts in an awkward angle, which is not ideal.
http://www.madabout-kitcars.com/foru...pictureid=1659

The Jaguar V6 is even bulkier, it is sitting at the right height, but too far back, giving the same the driveshaft problems.
http://www.madabout-kitcars.com/foru...pictureid=1655
Apart from the driveshaft problems, I would prefer to have the drivetrain center of gravity more forward, to improve handling. Furthermore, if I decide to turbocharge the engine, which is likely, one will have increased space issues AND the front turbocharger will heat up the cabin.


Enter the VW VR6 24V:
http://www.madabout-kitcars.com/foru...pictureid=1654
You can see that it can be positioned more to the front, giving straight driveshaft angles and moving the center of gravity forward as well.
The VR6 is compact and available from 2.8 to 3.6L, 204 to 300 HP stock. It is not a very sporty engine, it is quite undersquare and the internals are quite heavy. I hope to find a 3.6L version, giving between 260 and 280 HP and less undersquare. Lighter flywheel will hopefully make it more lively too.
On the plus side, it is very tolerant to turbocharging. As for turbos, the exhaust is at the back, where there is a ample space to place turbos, cats and exhaust, and lots of air around them to get rid of the heat. Due to the Max Power brigade turboing their Golf VR6's, there is a lot of experience and parts available in this department. I am thinking 400 to 450 HP in a twin turbo setup, to keep engine response and drivability as good as possible. This can be done without enhancing engine internals.

See below for a 3D pic of the setup:
http://www.madabout-kitcars.com/foru...pictureid=1657

Cheers, Kai

hondekop 6th January 2020 15:50

For the rest of the drivetrain, there are two major options. Due to turbocharging, the original gearbox will often break, especially with a mid engine setup which offers a lot more grip than the standard cars it came from (without turbocharging, the original 02M AKA MQ350 box can be used). The FWD transverse boxes that (more or less) keep up with the power are:

1. Getrag 6MTTxxx AKA Ford M66, ca. 55 kg, max. torque ca. 400-480 Nm. Used in many Ford and Volvo petrol cars.

2. VAG MQ500 AKA 0A6, ca. 85 kg, max. torque ca. 500 Nm. Used in many a few VAG cars like VW Tiguan or Seat Alhambra.

Both six speed, both do not bolt up directly (adapter plate necessary). Due to the lesser weight, better availability and better gear ratios I strongly favour the Getrag 6MTTxxx.

The Getrag 6MTTxxx marries to the Volvo S60 MK2 inner CV's, Volvo S60 MK2 driveshafts, Ford Mondeo MK 3 outer CV's, and Alfa 166 wheel hubs.
Alternatively, one can use Ford Mondeo MK 4 inner CV's, Ford Mondeo MK 4 driveshafts, Audi A6 C4 outer CV's, and Audi A6 C4 wheel hubs.
(Both options enable 5 x 108 mm PCD at the rear)

Up front, I think of Audi A6 C4 wheel hubs on the Fiat 124 stub axles, as this enables 5 x 108 mm PCD up front.

Brake wise, I think 312 mm vented discs front and 280 mm vented discs rear, as this fits 16 inch wheels. Brand mainly depends on the choice of hubs.

Ciao, Kai

rossnzwpi 6th January 2020 17:38

fantastic work Kai! I'd be interested in the detailed measurements you have of the Alfa V6. When considering the use of 108 x 5 hubs think also about the centre bore if you are getting Cromodoras with original sizing. They are way smaller than modern 108 (e.g. Ford/Jag) hubs. I think the repro Cromodora-look wheels may have a different offset to the originals too - but don't quote me on that. Alfa 166 hubs are similar size to original Dino.

thecarbuilder246 7th January 2020 11:42

246 engine?
 
Hi All

My two pennies worth. The trouble with taking a front wheel drive engine and box and placing it in a mid engine configuration is the weight transfer on high acceleration. When the box is in the front (front wheel drive) on acceleration the weight transfers to the rear of the car and often results in wheel spin and loss of grip. When you place the box in the rear or the car (mid engine) on hard acceleration the weight transfer means you have more weight at the back leading to more grip. More grip means the wheels will have less of a tendency to spin- this is what smashes the front wheel drive boxes. It's also why a lot of hot hatches with front wheel drive and 300+ horsepower now have electronic diff's. If I was starting again I'd go for a v6 from a lexus rx300 or rx350 which will bolt straight on to the toyota mr2 turbo box. This box is almost bullet proof and comes with limited slip diff as standard. I've seen mr2's and celica gt4's with upwards of 800 bhp. The lexus engine is also used in the lotus europa.
I will be sticking with my ford cosworth v6 and using a mr2 box via an adaptor plate. Ok not the lightest engine in the world but with 24valves and alloy heads and when turbo'd good for 400 bhp on stock internals. Plus I already have a brand new crate one/ a spare one and evrything that's needed to run it .

ian

ian

thecarbuilder246 7th January 2020 12:56

246 engine and box
 
Hi again

The toyota mr2 box will fit an alfa v6 engine too via an adaptor plate. I've seen them in the stratos, one turbo charged and pushing out over 400 bhp. Don't know if the intenet will bring up but try -turbonutters stratos mr2 box.

ian

hondekop 8th January 2020 00:30

Thanks Ross. To be honest, I have no measurements of the Alfa V6 & box. I just based the drawings on various photos, while using the bore size and oil filter diameter as references. Apart from that, some incomplete CAD drawings from sources you have found yourself already. Sadly, most of the photos are taken from an angle. As such, it is certainly not completely accurate, but a good indicator nevertheless. I have updated the drawing with the additional info I found.
PLUS, apparently the gearbox places the engine in a tilted position. The new drawing represents both:
http://www.madabout-kitcars.com/foru...pictureid=1662
This gives a better position, although the driveshafts are still at an angle.

The Duratec/Jaguar V6 drawing is pretty reliable (based on Ford drawings). As it is considerable bigger than the Busso V6, it is out of the selection.

I also updated the VR6 drawing to be more accurate:
http://www.madabout-kitcars.com/foru...pictureid=1661
Still the best position, although the driveshafts make a very small angle.
CG wise, it could be on par with the Busso: it can be placed further forward, but the VR6 is some 40 kg heavier.

Tough decision:
- Brilliant engine sound: both
- Weight: VR6 is substantially heavier
- Liveliness: definitively Busso
- Turbocharging: definitively VR6
- Required space: VR6 is easier

Don't know yet. To complicate matters further, there is also the Nissan VQ35DE: High revving, strong internals (turbo) and light. On the other hand, slightly bigger than the Busso. Available from the likes of Renault Espace, Vel Satis, or Nissan Murano.

Decisions, decisions; sigh.

hondekop 8th January 2020 00:40

As for the Audi 100 C4 & A6 C4 hubs, they have a 57.1 mm center bore, so you even need to add a spacer 57.1x58.1 mm diameter to reach the 58.1 mm center bore of the Cromodora replicas.
But you're right as for the Ford/Jag hubs, Center bore is a massive 63.4 mm.

Ciao, Kai

hondekop 8th January 2020 03:04

Quote:

Originally Posted by thecarbuilder246 (Post 103173)
toyota mr2 turbo box. This box is almost bullet proof and comes with limited slip diff as standard. I've seen mr2's and celica gt4's with upwards of 800 bhp.

The mr2 turbo E153 seems to be a very strong gear box indeed, accepting some 480 Nm. Problem is, they are getting quite thin on the ground (especially on the continent) and therefore quite expensive. Furthermore they are only 5 speed.

Ciao, Kai

rossnzwpi 8th January 2020 04:12

Kai, are there versions of the Audi C4 A6 hubs that are 108 x 5 instead of the usual 112mm. Or are you going to redial the hubs?

thecarbuilder246 8th January 2020 15:59

Quote:

Originally Posted by hondekop (Post 103178)
The mr2 turbo E153 seems to be a very strong gear box indeed, accepting some 480 Nm. Problem is, they are getting quite thin on the ground (especially on the continent) and therefore quite expensive. Furthermore they are only 5 speed.

Ciao, Kai

True they are only 5 speed-but woodsport do a 6 speed update/rebuild version if that's what you want. Expensive though. Personally 5 speed would do me ok. It was good enough for ferrari after all. I'm not worried about fuel economy a 6 speed would give me on a car only used when the sun's out. But each to there own I say. good luck

ian

hondekop 8th January 2020 17:03

Quote:

Originally Posted by thecarbuilder246 (Post 103185)
True they are only 5 speed-but woodsport do a 6 speed update/rebuild version if that's what you want. Expensive though. Personally 5 speed would do me ok. It was good enough for ferrari after all. I'm not worried about fuel economy a 6 speed would give me on a car only used when the sun's out. But each to there own I say. good luck
ian

Not a show stopper for me either, just something other boxes have as a (non essential) pro. Standard LSD is not a bad thing however.

hondekop 8th January 2020 17:17

Quote:

Originally Posted by rossnzwpi (Post 103179)
Kai, are there versions of the Audi C4 A6 hubs that are 108 x 5 instead of the usual 112mm. Or are you going to redial the hubs?

No, they are all 5x112 mm. But you can either redrill & tap them to 5x108, or remain 5x112 mm and use adaptation wheelbolts which can compensate for 2 mm offset/piece (3 euro/piece).
Front:
http://www.madabout-kitcars.com/foru...pictureid=1664
Rear:
http://www.madabout-kitcars.com/foru...pictureid=1663

Ciao, Kai

thecarbuilder246 10th January 2020 16:44

246 engine and box
 
4 Attachment(s)
Hi

Are you updating the engine and gearbox on an existing deon/jhclassic's dino? Or are you looking at building a new dino? Only asking as if you are updating an existing deon obviously you'll be struck with the original deon shell and it's dimensions.. If you were building new replica and want to use a later shell (say a cascu 246 shell) then you may have more room for you chosen engine and gearbox-as the cascu has slightly more room behind the driver. I've attached a couple of photo's that show the wheel arch on the deon is closer to the rear edge of the door and some 2 inches further back on the cascu 246. The tail of the dino 246 is also longer by almost the same dimension.

ian

size on deon photo is 14 inches-2 inches less than a 246 -photo is a bit blurred

hondekop 11th January 2020 20:32

Hi Ian,

I'm building on an existing Deon chassis & body, so I am therefore pretty limited space wise, sadly.
Was the Deon based on a 206 shell, then converted to use the Lotus Europa chassis? And Cascu bases its shell on a 246?

Ciao, Kai

hondekop 11th January 2020 20:58

See below for an estimate of the Nissan VQ35DE. Estimate because of the fact that I could not find sufficiently reliable data.
http://www.madabout-kitcars.com/foru...pictureid=1665

Again, engine & box are quite far back, resulting in a driveshaft angle of ca. 10 degrees. Not exactly ideal from an engineering perspective. There are CV joints with a maximum running angle (permanently) of 10 degrees and more, so it should be doable. Downsides are more vibrations, more friction and lower CV life. Last one is not that important for me.

Ciao, Kai

thecarbuilder246 12th January 2020 11:54

Quote:

Originally Posted by hondekop (Post 103201)
Hi Ian,

I'm building on an existing Deon chassis & body, so I am therefore pretty limited space wise, sadly.
Was the Deon based on a 206 shell, then converted to use the Lotus Europa chassis? And Cascu bases its shell on a 246?

Ciao, Kai

Hello Kai

I think it's documented on here somewhere but yes it was a mould from 206 shell altered to fit a europa chassis. Looking at the cascu shell and my dino shell I think the whole back was cut behind the door and moved forward some 2 inches or so. this would be why the deon/jhclassic is that way as that was moulded from that first car. The cascu engine lid is the same size but the boot lid is 70mm or nearly 3 inches longer.

ian

hondekop 12th January 2020 20:25

Funny, I always thought they extended the wheelbase to fit the europa chassis. I would really appreciate those 2 extra inches.

Have to cut up the car anyway because I do not fit in. But that is approx. in the middle of the door, where all body lines are more or less straight, so rather easy to extend. At the engine bay it's a completely different story, with a lot of sloping & curved lines.

Looking at the options, I still favour the VR6. VQ35 and Busso do fit acceptably in N/A form, but when the turbos are added space becomes a lot more dire:
http://www.madabout-kitcars.com/foru...pictureid=1666
(VQ35DE with turbos roughly at the position of commercially available turbo turbo manifolds).

Ciao, Kai


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