What car (do i chop up)
Discussion
I am considering a engine and gearbox for a project.
The project is a light weight offroader with a engine and transmission from a FWD car mounted longitudinally in a light chassis with the drive shafts going to a axle at either end.
I am looking at either 1.8 K-series and PG1 gearbox because they are light and I have lots of experience with the K-series or a the Zetec engine from my daily shed as its sat outside.
So any other ideas about a transverse mounted FWD car engine that is
1 light
2 reliable
3 cable shift for easy of running gear linkages
4 has the lowest first gear possible as running with range rover axles which have a diff of 3.54 I have a topspeed in first of 11mph and I want it lower
Ideally it would be a diesel auto with no brain but I don’t think a FWD diesel Auto with no brain exists
For reference the rover has a first gear of 3.25 and the ford is 3.667 higher the number the better
(Ps. 300bhp/ton a RWD American automatic car is really not suitable)
(Pss No MX5s)
The project is a light weight offroader with a engine and transmission from a FWD car mounted longitudinally in a light chassis with the drive shafts going to a axle at either end.
I am looking at either 1.8 K-series and PG1 gearbox because they are light and I have lots of experience with the K-series or a the Zetec engine from my daily shed as its sat outside.
So any other ideas about a transverse mounted FWD car engine that is
1 light
2 reliable
3 cable shift for easy of running gear linkages
4 has the lowest first gear possible as running with range rover axles which have a diff of 3.54 I have a topspeed in first of 11mph and I want it lower
Ideally it would be a diesel auto with no brain but I don’t think a FWD diesel Auto with no brain exists
For reference the rover has a first gear of 3.25 and the ford is 3.667 higher the number the better
(Ps. 300bhp/ton a RWD American automatic car is really not suitable)
(Pss No MX5s)
Risotto said:
I may have misunderstood, but why complicate matters by fitting a FWD/transverse engine longitudinally? Why not simply use an engine designed to be fitted longitudinally?
Okay a 4x4 such as a defender has 2 gearboxesThe first gearbox is identical to a normal RWD gear box. This will in first drop engine revs from 5000rpm to 1700rpm which is roughly dropping by a third.
In a RWD car this goes to the back axle which will drop it againby a third to about 570rpm at the wheels giving you roughly 30mph.
In a 4x4 the first gearbox feeds into a second gear box which will in high give no drop in RPM and in low it will drop it to about half giving a top speed of 15mph. Also in the second gearbox is a differential which will split the drive to front and rear diffs which drop the rpm again by a 3rd
In a FWD you have a combined gearbox and differential. So it takes the engine RPM and sticks it directly to the diff and to the left and right driveshafts which turn at wheel RPM. If you spin this by 90degrees then use the two driveshaft outputs to drive the front and gear axles then you get the correct drop in RPM to give you a nice low speed for offroad.
thinfourth2 said:
4 has the lowest first gear possible as running with range rover axles which have a diff of 3.54 I have a topspeed in first of 11mph and I want it lower
I'm not 100% on this but couldn't you put an older land rover diff (from a series II/III??) to get lower gearing as they are around 4.7.I know you can put RR diffs in older land rovers but not sure of the other way round. It might be an idea just to help go slower in first.
doogz said:
The ratio of first gear is surely irrelevant on it's own, since the drive passes through the donor gearboxes differential before it makes it to your diffs?
You need to look at the ratio of first gear, along with the FD of the donor box, no?
Or are you planning on removing/bypassing the diff from the donor box?
As, if it's an open diff, in said donor box, you're not going to make much of an offroader with it.
Cheers.
One gearbox from donor car no bypassing neededYou need to look at the ratio of first gear, along with the FD of the donor box, no?
Or are you planning on removing/bypassing the diff from the donor box?
As, if it's an open diff, in said donor box, you're not going to make much of an offroader with it.
Cheers.
MotorsportTom said:
I'm not 100% on this but couldn't you put an older land rover diff (from a series II/III??) to get lower gearing as they are around 4.7.
I know you can put RR diffs in older land rovers but not sure of the other way round. It might be an idea just to help go slower in first.
Considering series gearboxes but rangerover/disco axles are common and have disc brakesI know you can put RR diffs in older land rovers but not sure of the other way round. It might be an idea just to help go slower in first.
doogz said:
Liquid Knight said:
Oh another sprocket and chain set or flywheel on the front diff' driven by an old starter motor for reverse.
Really? A 4x4 offroader that will only go in reverse, at a single speed, and 2WD?Liquid Knight said:
Because the transverse drive shafts will be used as prop's for the twin diff set up.
Hayabusa.
Sprocket on the rear diff' and a prop to the front. I used two Vauxhall Omega diff's from a scrap yeard when I built by Bandit powered Panda 4x4.
Enjoy.
....outlined how to make it bike engine powered so it would have six forward gears and the motor for reverse. Hayabusa.
Sprocket on the rear diff' and a prop to the front. I used two Vauxhall Omega diff's from a scrap yeard when I built by Bandit powered Panda 4x4.
Enjoy.
thinfourth2 said:
Considering series gearboxes but rangerover/disco axles are common and have disc brakes
Thats fine but keep the RR axle and change the diff for an older one. I'm pretty sure it's do-able as my dad changed his old series II diffs for RR one's retaining the standard axles etc. 
For different ratios simply change the sprocket size and have the engine mounted on an adjustable platform to take chain slack up. The Omega differentials were both limited split ones and from identical cars to make sure the ratios were the same.
BMW/Omega Diesel diff's are longer ratio as well.
There are a few Paris Dakar rail buggies with Porsche 911 engines generally the gearbox differential is welded to send equal power to both the front and back. The rear differentials are welded and the fronts left limited depending on the application.
Why cable gear selectors a ninety degree linkage is only a matter of fabrication. you could use practically any engine you want. I'd be tempted with an Alfa V6. Light weight good power cheap and strong. Just find a rusty 156 and buy it for parts.
BMW/Omega Diesel diff's are longer ratio as well.
There are a few Paris Dakar rail buggies with Porsche 911 engines generally the gearbox differential is welded to send equal power to both the front and back. The rear differentials are welded and the fronts left limited depending on the application.
Why cable gear selectors a ninety degree linkage is only a matter of fabrication. you could use practically any engine you want. I'd be tempted with an Alfa V6. Light weight good power cheap and strong. Just find a rusty 156 and buy it for parts.
thinfourth2 said:
Okay a 4x4 such as a defender has 2 gearboxes
The first gearbox is identical to a normal RWD gear box. This will in first drop engine revs from 5000rpm to 1700rpm which is roughly dropping by a third.
In a RWD car this goes to the back axle which will drop it againby a third to about 570rpm at the wheels giving you roughly 30mph.
In a 4x4 the first gearbox feeds into a second gear box which will in high give no drop in RPM and in low it will drop it to about half giving a top speed of 15mph. Also in the second gearbox is a differential which will split the drive to front and rear diffs which drop the rpm again by a 3rd
In a FWD you have a combined gearbox and differential. So it takes the engine RPM and sticks it directly to the diff and to the left and right driveshafts which turn at wheel RPM. If you spin this by 90degrees then use the two driveshaft outputs to drive the front and gear axles then you get the correct drop in RPM to give you a nice low speed for offroad.
With most off roaders you'd also lock the centre diff. In you setup it'd still be open. Not sure what you are planning, but it think a similar setup was used on Scraphead Challenge once. It's was dreadful off road as the lack of locking diffs meant it spent most of it's time as a 1wd vehicle.The first gearbox is identical to a normal RWD gear box. This will in first drop engine revs from 5000rpm to 1700rpm which is roughly dropping by a third.
In a RWD car this goes to the back axle which will drop it againby a third to about 570rpm at the wheels giving you roughly 30mph.
In a 4x4 the first gearbox feeds into a second gear box which will in high give no drop in RPM and in low it will drop it to about half giving a top speed of 15mph. Also in the second gearbox is a differential which will split the drive to front and rear diffs which drop the rpm again by a 3rd
In a FWD you have a combined gearbox and differential. So it takes the engine RPM and sticks it directly to the diff and to the left and right driveshafts which turn at wheel RPM. If you spin this by 90degrees then use the two driveshaft outputs to drive the front and gear axles then you get the correct drop in RPM to give you a nice low speed for offroad.
So my suggestion would be to look for something fwd with a LSD.
Again not knowing what you are actually designing or using it for. But is a pg1 going to be strong enough?
If it's a light vehicle and with sensible sized tyres then a budget way of gearing down would be to run Series Land Rover 4.75:1 diffs. No where near as strong as the 3.54's but should bolt straight in.
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