I did it - RWD & straight pipes on my 640.

I have heard because the Murcie rear wheels are not in line with the front that in 2wd the dynamics are really thrown off in 2wd and due to the geometry of the car the rear will break easier than different cars.

My 6.2 hasn't had a single issue with the RWD conversion. When discussing control, the RWD conversion makes it more to handle in the corners. I drive mine like an Italian Viper. The rear can and will get away from you if you aren't careful.

I have heard because the Murcie rear wheels are not in line with the front that in 2wd the dynamics are really thrown off in 2wd and due to the geometry of the car the rear will break easier than different cars.

It has a wider rear track, like many performance/race cars.

 

The odd dynamic of the Murci is the combination of weight in the back with a wide rear tire (26.4" footprint) and a skinny front tire (19.2" footprint). So the car likes to understeer (push) through turns because the front tires don't bite in comparison to the traction in the rear, AWD makes the understeer worse. The other situation where this dynamic is apparent is when the car starts to spin, there isn't much steering geometry in the Murci and once the wide rear tires break traction, the skinny front tires don't have enough grip to keep the tail in line. Further, for some reason the AWD system isn't a safety net like in other vehicles (STi, EVO, Audi) to help bring the car back in line when the tail comes out. I don't think AWD or 2WD will be able to change the dynamics as much as a wider front wheel/tire would (like JonV did).

 

skip to 6:30 to see what I'm talking about

 

 

screwing around with 2WD and counter steer

It has a wider rear track, like many performance/race cars.

 

The odd dynamic of the Murci is the combination of weight in the back with a wide rear tire (26.4" footprint) and a skinny front tire (19.2" footprint). So the car likes to understeer (push) through turns because the front tires don't bite in comparison to the traction in the rear, AWD makes the understeer worse. The other situation where this dynamic is apparent is when the car starts to spin, there isn't much steering geometry in the Murci and once the wide rear tires break traction, the skinny front tires don't have enough grip to keep the tail in line. Further, for some reason the AWD system isn't a safety net like in other vehicles (STi, EVO, Audi) to help bring the car back in line when the tail comes out. I don't think AWD or 2WD will be able to change the dynamics as much as a wider front wheel/tire would (like JonV did).

 

skip to 6:30 to see what I'm talking about

 

 

screwing around with 2WD and counter steer

 

 

Nice explanation.

Only downfall to going RWD is the archaic traction control system Lambo has on the Murci. With a RWD conversion traction control has to be turned off or it will kick in and cut power all the way up to 4th gear. The rear end doesn't break loose from 3rd to 4th but traction control still kicks in and cuts off all power for 2 seconds - it gets annoying so you turn it off.

 

The rear end becomes extremely loose which gets scary sometimes especially when going 60+. Wish the Murci had a modern day TCS rather than its prehistoric system.

 

Overall the car is quicker and more enjoyable to drive, but the downfall is it becomes dangerous.

I turn the TC off the moment I get into the car. It cuts power even with 4wd...

I'm tempted to go RWD. I just changed the clutch to a nice kevlar one and i'm sure it will last a long time but I know this AWD just eats it more on initial take off. I'm running R888 sticky toyo tires so traction is already really good too.

I cant imagine it will feel or handle much different than my Diablo SV.

What the heck! Why wasnt I invited to this conversation, I'm mentioned at least twice

 

 

Guys I appreciate the respect, I realize I have experiences that are different then others, and lord I sure wish I didnt have those experiences. But I absolutely broke TWO Murci Differentials while doing RWD. I have since swapped back to AWD and now run an lp640 rear differential (drive wise, you cant tell any difference, but the output shaft hubs are stronger.

 

I'm not going to wish it on anyone of course that something break, but on early murci's I'd be more worried about the conversion. The LP640s differentials are more stout on the output shafts (about their only real difference), and so the OP should be fine.

 

As far as OP loving the setup and not seeing any issues with the Egear, so your telling me your not getting any 'bucking' ??? Did you have your egear PIS changed? OH or are you one of the lucky 09 owners (which my understanding is thats THE best year for egear programming). So maybe your cars egear program is sophisticated enough to manage the change. The early non LP cars just dont know how to change from having that heavy driveline to a lighter one, and so you get some odd bucking during the summer when you run them hard. Once it cools down, it goes right back to normal.

 

I wish all my Murci Brethren the best of luck with modding and what not, but all I can do (and I hope everyone does it as well), is share experiences.

 

 

Yes, I also converted to 9 inch wide front tires, with 265 rubber to help get more footprint up front.

 

Happy to answer any questions folks may have. As far as unstable going to RWD, I never had that issue, I loved the excitement of tossing the ass around, its like someone said above, Italian Viper. Good Analogy. The only negative I had with RWD was in the rain, you definitely cant take off or accelerate as quickly, and yes two broken differentials. If it wasnt for those two issues, I'd still be RWD, its a ton of fun.

 

Oh and 1 more thing, I've also converted to an LP640 transmission, which I am sure few know has SHORTER gear ratios, so it gives a little more PEP to a non lp640 car, as now they have more advantage over the tires

 

Thanks,

 

Jon

I cant imagine it will feel or handle much different than my Diablo SV.

 

i would think you are correct.

I'm tempted to go RWD. I just changed the clutch to a nice kevlar one and i'm sure it will last a long time but I know this AWD just eats it more on initial take off. I'm running R888 sticky toyo tires so traction is already really good too.

 

What year car? IF you are early Murci, with egear and with that kind of traction (sticky tires) and 'grab' you will get from the Kevlar clutch, you will be the perfect use case for my hypothesis that all early murci's will eventually break their rear differential with RWD conversion, as its a matter of time, not 'if' (Whiteout disagrees, and I respect that, because he hasn't had any issues with his early murci when he did RWD).

 

I know I am the naysayer, and it sucks (for me), but I am glad people are respectful about my alternate opinion, makes it easier to share.

 

Also I am quite well versed in swapping major components out of these cars now, so anyone ever need questions about that stuff, ask me.

What year car? IF you are early Murci, with egear and with that kind of traction (sticky tires) and 'grab' you will get from the Kevlar clutch, you will be the perfect use case for my hypothesis that all early murci's will eventually break their rear differential with RWD conversion, as its a matter of time, not 'if' (Whiteout disagrees, and I respect that, because he hasn't had any issues with his early murci when he did RWD).

 

I know I am the naysayer, and it sucks (for me), but I am glad people are respectful about my alternate opinion, makes it easier to share.

 

Also I am quite well versed in swapping major components out of these cars now, so anyone ever need questions about that stuff, ask me.

 

 

I have an 09 LP640 Egear with the bosch throttle bodies that started this in 09 and 10 only. Its really smooth actually and I have the PIS very tight.

Mine is an 08 and I haven't felt any bucking so far; if anything it feels a bit easier to get moving from a stop than awd did. I had actually wondered about needing to adjust the PIS but so far we haven't and it's super smooth.

 

I have not had it at high speed yet, mostly just some light canyon driving. The car still has some understeer but it feels different now, that may be something to do with the lighter feeling when comparing it to before. Edmond is right on though, the car will easily break it loose if you stab it, especially in 2-3. My old Plastic mess-06 did the same with TC off so it's not unexpected for a high hp rwd car; I personally love it as I'm more used to RWD cars and can better predict how it should react than I could with AWD. A big part of that is like they say in the top gear video, being afraid to push it too far (with AWD) as once it starts going it's already gone.

 

Allan - you need to have Edmond give you a ride some time - it will blow your mind compared to the Murci with AWD; it's a gamechanger for the car. His is a manual as well so you'll get a better idea than I could give with egear.

 

Lambofan35 - if you are on the fence I would just try it. I really regret that I waited 2 years to do this; I fell in love with the car all over again.

yeah 09+ is by far the best system, its definitely the way to go if you are doing egear, Bosch and Lambo got it right with this setup, really smart how the throttle bodies, transmission and engine all work together in these cars. Congrats!

 

 

 

As a side note, anyone who breaks their regular murci diff, I have a spare one ))

Had it done to my previous Murcie, car surely felt quicker but after a month I put back the awd. Started to miss the planted feeling the awd gives.

Thank you Samlambo for your feedback. It helps me to Never EVER consider going rwd no more, even though it has cross my mind a bunch of time. The planted feeling is a key confident to take this Bull all the way pass the 200mph mark. I have not attempt this speed yet, but it is something I would like to run some day.

On a second thought...have any of the rwd conversion guy achieve the 200mph speed?

Thank you Samlambo for your feedback. It helps me to Never EVER consider going rwd no more, even though it has cross my mind a bunch of time. The planted feeling is a key confident to take this Bull all the way pass the 200mph mark. I have not attempt this speed yet, but it is something I would like to run some day.

On a second thought...have any of the rwd conversion guy achieve the 200mph speed?

I dont think AWD is going to help feeling planted at 200mph..

Thank you Samlambo for your feedback. It helps me to Never EVER consider going rwd no more, even though it has cross my mind a bunch of time. The planted feeling is a key confident to take this Bull all the way pass the 200mph mark. I have not attempt this speed yet, but it is something I would like to run some day.

On a second thought...have any of the rwd conversion guy achieve the 200mph speed?

 

Close enough and the car is planted. Windshield wiper isn't.

 

 

 

Thank you Samlambo for your feedback. It helps me to Never EVER consider going rwd no more, even though it has cross my mind a bunch of time. The planted feeling is a key confident to take this Bull all the way pass the 200mph mark. I have not attempt this speed yet, but it is something I would like to run some day.

On a second thought...have any of the rwd conversion guy achieve the 200mph speed?

 

Sure bro. I remember reading sometime ago someone mentioning he took it over 300km/hr.

Close enough and the car is planted. Windshield wiper isn't.

 

Come to think of it, my windshield wipers in my older Murcie were perfectly fine at around 280km/hr. Not been higher though.