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Engine Specific Info and Questions => IDI Engine => Topic started by: westcoaster on March 16, 2010, 08:55:16 pm

Title: '87 jetta 1.6td stock tire size?
Post by: westcoaster on March 16, 2010, 08:55:16 pm

Alright! :D

Things are clicking here!

Thanks to GerryGTD for this post regarding what transmission is in what year car
http://www.a2resource.com/eandt/transmissions.html (http://www.a2resource.com/eandt/transmissions.html)

Thanks to Rabbitman for the link to this page that details transmission gear ratios
http://www.scirocco.org/gears/ (http://www.scirocco.org/gears/)

What I am trying to do is a comparison between the stock VW drive train and the stock suzuki samurai drive train. I would like to replicate as close as possible the stock VW final drive in the samurai.

One last piece of the puzzle I am missing is what size tire was stock on an '87 jetta? (I don't have a jetta car otherwise I would just go look)

Title: Re: '87 jetta 1.6td stock tire size?
Post by: theman53 on March 16, 2010, 09:17:55 pm

If I remember my 86 jetta is a 175/70/r13   which is almost identical to 155/80/r13  or  185/60/r14  both of which came on some of my MKI Rabbits.

Here is the cool tire size link calculator thing   http://www.miata.net/garage/tirecalc (http://www.miata.net/garage/tirecalc)

If you didn't have it already.

Title: Re: '87 jetta 1.6td stock tire size?
Post by: westcoaster on March 16, 2010, 11:19:29 pm

Thanks!

So...
vw tranny.
Final drive 3.94

1st 3.45
2nd 1.94
3d 1.29
4th 0.91
5th 0.75

Tire size of 175/70R13

samurai tranny
final 3.73 plus transfer case of 1.409 = 5.139

1st 3.652
2nd 1.947
3d 1.423
4th 1.00
5th 0.795 (or 0.865 post 88.5)

I'm having trouble getting my head around how to figure the samurai tire size.
VW gears
0.75 (5th) and 3.94 (rear) with a tire size of 175/70R13 = 3000 engine RPM "A"
compared to the samurai gears
0.795 (5th) 1.409(xfercase) 3.73 (rear) with a tire size of ?? = 3000 engine RPM "A"


Name of the game is to have the same surface speed for an engine rpm in 5th gear


The above post was edited...

Title: Re: '87 jetta 1.6td stock tire size?
Post by: westcoaster on March 17, 2010, 12:38:54 am

I think I got it figured out... :P

found one of the many on line gear calculators
Stock VW with 175/70R13 tires a 0.75 fifth gear and a 3.94 differential runs 68.4 MPH (110Kmh) at 3000 RPM

stock samurai gears
241/79R15 (converted 30X9.5R15) 0.795 fifth (pre 88.5) 5.139 rear (1.409 plus 3.73) runs 65.52 MPH ( 105.4Kmh) at 3000 rpm
267/76R15 (converted 31X10.5) 0.795 fifth (pre 88.5) 5.139 rear (1.409 plus 3.73) runs 67.67 mph (108.9Kmh) at 3000 rpm


Finally AFTER I do my swap I figure this out...