TehRaydarlover's AWD Lover

[TehRaydarlover]

Thanks! Yeah it was definitely a good weekend task, or more depending on how anal you are haha. After taking with Jim at MM a few times he suggested I tighten up my backlash to 0.003". I might try to adjust it a little more before I install it, I'll have plenty of time before the car is road worthy lol.

[driftxsequence]

Wow this is awesome! I love the rebuildable VC idea. I hope it works out. How long do you think it took to rebuild the rear differential? It appears to be a weekend job in itself.

[boogle2]

I will be disassembling my two transfer cases in a couple months here.... this is some great info.

Rob

[Nisse Järnet]

Exactly, it would create tons of heat :)

The car felt "lighter" with the E34 parts actually, less strain when parking etc. It feels more like my rwd E30 than the stock ix for some reason.

[nando]

Right, thats only 10%. Thats my point - its not a fixed value, the ix is about 25% at stock power, but if it was still 25% at 800hp you would melt something lol. It wouldn't be that different on a 525ix either.

I actually plotted it out at one point using a stock ix, mine, and a super high power turbo ix with known bhp and whp losses. At stock power, it takes about 40hp, but if you double the hp input, the drivetrain loss doesn't double..

[Nisse Järnet]

I don't think the drivetrain loss is 30% - also it's not linear. if you are making 800whp the % decreases quite a bit. it's more like a slope/offset than just a straight percent. most of it is fixed by the drag of the drivetrain (whatever power it takes to rotate everything).

in any case I think you are on the right track with your calculations. I've read anywhere from 40-20% air volume at room temperature. The less air, the more it will lock, but it can also blow up that seal faster.

The dyno measured ~80hp loss between the "road" and engine on my ix. (720awhp, 800hp) Not sure if its more or less losses on the E30ix parts though?

[FAROYE.MOTORSPORT]

[QUOTE=TehRaydarlover;4563843]I added some more detail about filling the VC to my last post on the previous page.



Thanks! Curious, what was the failure point in your two broken diffs? I'm guessing the spider gears, but maybe the crown gear?

Ray


Thank you for your interest, I have broken two spider gears, and impossible to remove the shaft, I had to cut the casing for disassembled


I can send you a message to improve the diff front ?

thanks you

Remy



Little movie of my Ix snow , e30 lover !!

https://youtu.be/oatRIAcfGqU

[TehRaydarlover]

True, my point was just that some of the drivetrain loss goes into friction and heating the parts up.

Yeah, 12.5ml seems logical to me. I might take a little more out just in case. The one write up that Jusso posted the translation of, a few years ago, showed the welded cover breaking. Whether that was from a bad weld job or the vc being over filled I'm not sure but I'd rather not have the same experience.

[nando]

I don't think the drivetrain loss is 30% - also it's not linear. if you are making 800whp the % decreases quite a bit. it's more like a slope/offset than just a straight percent. most of it is fixed by the drag of the drivetrain (whatever power it takes to rotate everything).

in any case I think you are on the right track with your calculations. I've read anywhere from 40-20% air volume at room temperature. The less air, the more it will lock, but it can also blow up that seal faster.

[TehRaydarlover]

Working on getting the transfer case back together.

I assembled my spare VC and used a syringe to add mineral spirits 10ml at a time. It came out to almost exactly 160ml (or 5.41oz)



Using the coefficient of thermal expansion that Eskie outlined in the link above of 0.00096cc/cc/°C I can calculate the amount of air I should have in the VC to allow for thermal expansion.

160ml = 160cc

160cc x 0.00096cc/cc/°C = 0.1536cc/°C

I'm assembling this at room temperature of 70°F or 21°C. I did a little research on how hot a transfer case should get (mostly coming from jeep forums) and it sounds like they can get over 200°F. That seemed really hot at first but then I thought about it. The engine is right there the exhaust is right there. ~30% power loss to the drivetrain has to go somewhere. Looking at the x profile o-rings they are only good for 230°F. I decided to go with 200°F (93°C)

93°C - 21°C = 72°C

0.1536cc/°C * 72°C = 11.06cc or 11.06ml for me

With this I will open up the fill hole on my VC and make sure it is completely full then remove about 11.5ml of silicone fluid. This should give me enough room for thermal expansion and keep the VC from exploding. :D

[TehRaydarlover]

Thanks guys, Eventually I'll give an update with the front diff. Welder got a little happy with the heat and it locked up. In the process of cutting it apart and trying again.

If I remember correctly someone found someone send some V/C silicone out to be tested for viscosity and 88k cst is what the lab measured. I'd have to go back and check to make sure, it's been over 2 years since I did it. Crazy.

I'm interested to hear what you come up with volume wise, I measured mine with mineral spirits using the parts washer at work. Again, if my memory serves me I think it was 4.5oz with the plates and spacers in...

Also I don't know if this helps, but here is the link to the post where I referenced the expansion of the xiameter silicone from a pdf file on dow's website:

http://www.e30tech.com/forum/showpos...0&postcount=15

Cool, I'm glad we have some sort of source for the viscosity.

Nice reference, I think there might also be something in the SDS that came with from Krayden. (edit: nvm couldn't find anything in the SDS) I didn't get to it this weekend (was picking up a very special part :D) but hopefully after work sometime this week.

[litu]

Not sure are here some info for that upgrade that front diff for all those turbo ix owners who is broken it

http://www.r3vlimited.com/board/showthread.php?t=180631

[23732]

As I am turboing my iX, I am very interested in the front differential reinforcement. Keep us updated.

Also, you have amazing skills and knowledge. Keep up the good work!

Best regards from us, crazy Scandinavians ;)

[rzerob]

Subscribed.

[Eskie]

If I remember correctly someone found someone send some V/C silicone out to be tested for viscosity and 88k cst is what the lab measured. I'd have to go back and check to make sure, it's been over 2 years since I did it. Crazy.

I'm interested to hear what you come up with volume wise, I measured mine with mineral spirits using the parts washer at work. Again, if my memory serves me I think it was 4.5oz with the plates and spacers in...

Also I don't know if this helps, but here is the link to the post where I referenced the expansion of the xiameter silicone from a pdf file on dow's website:

http://www.e30tech.com/forum/showpost.php?p=1371170&postcount=15