Using 4.11's with an A341e

[2khamisj]

Hey, I recently got my hands on a UZS141 halfcut which I am using to convert into my VS lexcen. I plan to run my standard borgwarner m78 diff, however convert to an LSD centre and upgrade the ratios to 4.11. I have a ratio change calculator to find out my projected speeds at what RPM, however in order to calibarate the calculator I need to find RPM iat 100km/h in 4th as per a factory spec vehicle. The car in question is a 93' Crown Majesta. If anyone could assist in providing some sort of figure it would be muchly appreciated Thanks.

 

[cjsupra90]

(RPM x TC) / (1056 x TR x AR) = Speed

no calibration needed...

RPM = Engine RPM
TC = Tire circumference
TR = Transmission Ratio (of any particular gear)
AR = Axle Ratio

 

[cjsupra90]

Oh, tire circumference is in inch's and the speed output is MPH. I dont know if using MM or what not will make the outcome be in Km/H...

Sorry, dont have to deal with metric speed readings here in the states...

 

[2khamisj]

Oh, tire circumference is in inch's and the speed output is MPH. I dont know if using MM or what not will make the outcome be in Km/H...

Sorry, dont have to deal with metric speed readings here in the states...

Is AR the same as what a diff ratio is? I.e number of revolutions wheels must make to equal 1 tailshaft revolution?

 

[cjsupra90]

Yes, the AR (axle ratio) is the Diff Ratio, so if you were using 4.11 gear set, the you would use 4.11 for the AR location of the equation.

 

[cjsupra90]

If you happen to have Microsoft Excel, here is a speed calculator that I wrote. Again, speed is in MPH and it automatically calculates the TC spec based on the tire info that you put into it....

Anything that is in Blue is changable like tire specs, gear ratio's ect....

..............

Ok, it wont let me attach it cause of the 9.8k size limit for .xls files and it is 20K so if you want it, PM me your email address and I will email it to you.

Also, if anyone knows a way that I can get it up here or host it for me, let me know.

 

[Peewee]

Does the VS Lexcen use a speedo cable or electronic?
If it uses electronic just use a speedo corrector from Jaycar to adjust it.

If it uses a cable then you'll need to convert the autobox to a cable output, and you'll need to change the cog to either a 19/6 or a 20/6

 

[cjsupra90]

ok, I just updated it now so it has both MPH and Km/H units in it.. and like before, it calculates everything for you with just some basic needed info...

 

[2khamisj]

Does the VS Lexcen use a speedo cable or electronic?
If it uses electronic just use a speedo corrector from Jaycar to adjust it.

If it uses a cable then you'll need to convert the autobox to a cable output, and you'll need to change the cog to either a 19/6 or a 20/6

Yeah it uses an electric speedo, I'm not worried about having my speedo out, I'm trying to use an excel spreadsheet to calculate what rpm I'll be sitting on at 100km/h... I'm thinking with the .75 o/d ratio this gearbox should be okay with it but I'm not sure, trying to figure out if I will lose too much top end. None the less thanks for the replies

 

[2khamisj]

This is the program I am using

 

[cjsupra90]

Ah, didn't even think about ZIP'ing it to attach it......

That one is deffinitly set up a bit better then the one that I wrote.
I like the idea of being able to compare to different diffs.

Here is the one that I wrote. Fill the Blue numbers with the info for your setup and the outcomes are in Red. It is locked so you can only change the blue.... Its not the most organized but I think its pretty easy to understand.

 

[2khamisj]

Oh yes...why are there 2 sets of outcomes in red down the bottom? Which one am I sposed to be reading?
As you can see from the spreadsheet I use, it mentions a calibration in which you need to set the engine RPM @ 100km/h in order to get the correct calculations

 

[Peewee]

Yeah it uses an electric speedo, I'm not worried about having my speedo out, I'm trying to use an excel spreadsheet to calculate what rpm I'll be sitting on at 100km/h... I'm thinking with the .75 o/d ratio this gearbox should be okay with it but I'm not sure, trying to figure out if I will lose too much top end. None the less thanks for the replies

Sorry, misread.
Basically with a 4.1 diff, at 6500rpm you'll be doing 190kph in a 1:1 gear ratio.
6500rpm in OD will be ~270kph

(I'm pretty sure the A341E has a 4th of 0.705:1)

First will top out around 75kph, second around 125kph.

This is based on a 235/45/17 tyre (643mm height)

 

[2khamisj]

Oh okay great thankyou very much

 

[cjsupra90]

The first set is MPH and the second Km/H.... I added a converson to Km/H in it after I orginally posted about it...