Alfa Romeo Forums banner

1 - 20 of 28 Posts

·
Registered
Joined
·
272 Posts
Discussion Starter #1
I have a hotrod buddy who wants to put a transaxle behind a 4.1L Ford inline 6.
These things are good for about 200hp but have truckloads of torque.
The car will probably weigh less than 1000kg

I reckon a V6 transaxle will cope with room to spare but after seeing one in the flesh he reckons they're too small.

So just how much HP can these things safely cope with in stock form?
 

·
Registered
Joined
·
2,984 Posts
I have seen posted somewhere around 400hp?
my guess is my cars with a S spec is close to 200..

but it is the torque that will snap one not the power? if all the power is at say 10K they it will handel a lot more then the same power at 6K

I think the 3.0 is a stronger box then the 2.5L as the diff seems to be the weaklink
and with the taller rear in the 3L box the pinion is larger and that seems to be the part to go first.

how much torque are you looking at?

the 3L is around 210 Ft/lbs
and the supercharged is a lot more.
 

·
Registered
Joined
·
203 Posts
3.2l Turbo Alfa v6 breaks the V6 transaxle,no problem..This happens purely under sustained acceleration and not being harsh and transferring shock loads into it..
This is the reason we tend to put the BMW Getrag box up front with a diff. at the back.
Coming onto the main straight at Kyalami it would go into boost and hold it for maybe 8 second..A pop sound and the pinion is turned off..
This was after the casings expanded and the gears crunched themselves first though.we strapped the casings and the next to go were the pinion head.
 

·
Registered
Joined
·
400 Posts
A friend used to run a twin turbo 3l V6. He used a stock cloverleaf transmission with LSD and only broke one in about 3 years of 'enthusiastic' use. A factor maybe is that he used fairly conservative tyres. 225 width road cut, not slicks. Power plot attached form the motor after it had some smaller turbos fitted. It did make more power before this with the bigger turbos, but he had a bad day and melted the turbines, so took the oportunity to go for a smaller and more responsive setup. I saw a later power plot for this car once boost control had been sorted and the torque was almost flat from about 2k.

I should add that I am in no way disputing the info Barryh has given - he's got the first-hand experience after all, just adding something I happened to know that might be helpful.
 

Attachments

·
Registered
Joined
·
3 Posts
I have a hotrod buddy who wants to put a transaxle behind a 4.1L Ford inline 6.
These things are good for about 200hp but have truckloads of torque.
The car will probably weigh less than 1000kg

I reckon a V6 transaxle will cope with room to spare but after seeing one in the flesh he reckons they're too small.
I am the philistine that proposes putting an Alfa transaxle behind a Ford 4.1 inline 6.

For those who wonder why:
I have always had a soft spot for the deDion style rear end.
The Alfa package is very easy to graft into another vehicle.
Placing the clutch and gearbox at the rear of the vehicle will improve weight distribution.

I had seen pictures of the transaxle which clearly illustrated the configuration but did not show the dimensions of the unit, and when a couple of days ago I saw one on the ground for the first time it was much smaller than I had expected, and hence my concerns.

The 4.1 is a plodder, putting out max power of 200hp/5000rpm and and more importantly max torque around 250lbft/3000rpm. The vehicle will have a mass of under 1000kg with 195/15 road tyres and will never be raced.

Any hints, advice or guidance welcome.

Peter


Edit
The graph above was hidden until I logged in officially. Judging by that, I should not have any problems.

The motor can easily push a tall final drive, any particular models to look for or steer clear of?
 

·
Registered
Joined
·
203 Posts
Peterr,
Under those circumstances I would have no problem in using the v6 tx..
I was under the impression it would be turbo charged..The Aussies have a 4.1 turbo putting out 600 nm or something similar and that IMO would crunch the tx for breakfast..
The ratios going to be good enough for you??
 

·
Registered
Joined
·
3 Posts
Peterr,
Under those circumstances I would have no problem in using the v6 tx..
I was under the impression it would be turbo charged..The Aussies have a 4.1 turbo putting out 600 nm or something similar and that IMO would crunch the tx for breakfast..
The ratios going to be good enough for you??
The output from the 4.1 is limited by the valve size, so they really respond to force feeding. Some of the blown 4.1 sixes and the 3.9 that succeeded it are putting out astonishing torque, but still at relatively low RPM.

The gear spread will probably wider than ideal, but I can cope with that. The diff ratio should be about 3.0~3.5, which means a 90 2.5 is probably the one to look for. I have no idea if this is a common model in Australia.

The stock Ford 4.1 uses a 9" clutch which is swapped for one with a heavier diaphram after even moderate engine tuning, the Alfa appears to be much smaller than that, I still wonder how it would handle the torque.
 

·
Registered
Joined
·
400 Posts
Ah, I've just spotted something.....I misunderstood you I think...the unit I was talking about is the 164 FWD box. I think you are talking about the Milano style box aren't you?? In which case...I know nothing!! Sorry for the mis-information.
 

·
Registered
Joined
·
4,075 Posts
Barry, how much horsepower did that 3.2L turbo monster have? Was it a 24valver? You have me scared because I am planning on bumping my brown GTV6 way way up and being carefull.
 

·
Registered
Joined
·
561 Posts
Peterr: Why in gods name a 4.1 Ford engine? Surely if you wanted to use a pushrod boat-anchor engine, wouldn't you use a 265 Hemi... in E49 spec complete with the Webers.

Now as far as cheap old Aussie iron went: they just did not get any better!
 

·
Registered
Joined
·
203 Posts
Barry, how much horsepower did that 3.2L turbo monster have? Was it a 24valver? You have me scared because I am planning on bumping my brown GTV6 way way up and being carefull.
Greg,It made 350 odd wheel hp and 480 odd Nm torque.It was a 12valve engine,Big valves and a nice cam grind..
The propshaft was stock std.
It was distorting the casing to such an extent that the gears would climb all over themselves and grenade..A lot of bracing and welding later,the pinion head at the main pinion bearing proved to be the weak point.
The next step was the 6 speed M3 box and the E39 m5 diff..
 

·
Administrator
Joined
·
12,932 Posts
There was an Alfetta that raced in NZ with a full race Chev v8 up front and a v6 transaxle at the back ... he used to get a couple of race meetings out of them :eek:

Pete
 

·
Registered
Joined
·
4,090 Posts
Thanks Barry. Thats too bad, I thought it could handle 350 at the wheels if driven with care. I guess not!
How about limiting the torque? That is probably what kills the box. With aftermarket engine management it should be simple to detune, no? Or, just go naturally aspirated ;)
Jes
 

·
Registered
Joined
·
4,075 Posts
Jes, I don't want to go through the trouble of building a 400hp motor and detune it to 300hp. That's just not efficient. It makes a lot more sense to build a 300hp motor in the first place.
 

·
Registered
Joined
·
4,090 Posts
Well, if max torque (killing the box) and max HP do not happen at the same engine parameters, e.g. RPM, then you could detune max torque yet get your max HP. This is all hypothetical, but that was kind of the thinking. This is similar to what Volvo did with the S60 and V70 R cars. You will see that the automatics have detuned torque yet identical max HP. I'm guessing that the torque would otherwise wear out the automatic trannys.
Jes
 

·
Registered
Joined
·
96 Posts
The next step was the 6 speed M3 box and the E39 m5 diff..
Hi there, is there anywhere you can point me to so that I can see how this was done?

Thanks, Graham
 

·
Registered
Joined
·
203 Posts
Graham,see gtv6.com..-performance-single turbo install.
Im sure I posted pics there.
Alternativly let me search for pics on one of my backup drives..
 

·
Registered
Joined
·
96 Posts
Thanks Barry, but the pictures stop just after you dropped the engine in and fabricated the intake etc. In one picture there is a tantilizing shot of the gearbox in the distance :)
 
1 - 20 of 28 Posts
Top