Tech question on final drive

[DanielForest]

Hi,

If I want to check if my ring and pinion are 11/53, is it just meaning the pinion got 11 teeth while the ring got 53?

All my interenet queries found info about drive ratio (4.08) but not about how to check what is the part if laying on your desk

 

[ng_randolph]

Yes, as simple as counting the teeth.

 

[Dr.Jeff]

And obviously the number of teeth on the two gears can be divided to get that "final drive ratio"; 53 divided by 11 = 4.818

 

[DanielForest]

Finally, Jeff could be of some use... sometimes!

Next question will be more tricky. How could I know if a part will fit a 1300 or a 1500? Don't think there are interchangeable.

 

[Jeff Stich]

Next question will be more tricky. How could I know if a part will fit a 1300 or a 1500? Don't think there are interchangeable.

The ring & pinion have nothing to do with the engine (1300 or 1500), they are dependent on the transmission being used (4-speed or 5-speed).

 

[DanielForest]

The ring & pinion have nothing to do with the engine (1300 or 1500), they are dependent on the transmission being used (4-speed or 5-speed).

Yes, I know, I was not refering to the the engine but to the model since here in North America all 1300cc got a 4 speed while the 1500cc a 5 speed.

 

[Jeff Stich]

Yes, I know, I was not refering to the the engine but to the model since here in North America all 1300cc got a 4 speed while the 1500cc a 5 speed.

Either transmission will fit either engine, people do these swaps all the time (often a 5-speed swap into a 1300 car or 1500 swap into a 4-speed car).

You asked "How could I know if a part will fit a 1300 or a 1500?".

If you could define what you mean by "a part", maybe we can help you better.

 

[DanielForest]

If you could define what you mean by "a part", maybe we can help you better.

A9/53 ring and pinion set (5,88 ratio) I bought slighlty used 18 years ago and was supposed to be a performance part for the 5 speed X1/9. Before dismantling a transmission to put it in, I want to make sure I wasn't just naive. I have no idea where it came from. The seller was discarding some hi-performance parts he didn't need anymore and I couldn't resist. I know it will probably be a perfect modifications for quick sprints off the line, but no good for mid-range accélérations cause I will need to shift more often, and I will also loose top speed.

 

[Ulix]

Hi Daniel,
Just post a pic of it here and some people will be able to answer.
5.88 is awfully short.
Rpms will be 1.44 times higher than stock.
Cruising at 4000rpm will become 5765rpm.

 

[DanielForest]

At least, the numbers were right. This is a 9/53. Just need to know if it's for a 5 speed X1/9.
I don't intend to use it for street driving, only for AutoSlaloms.

 

[kmead]

On a 1500 you may find you have to actually shift more which can be an issue depending on the course.

What types of courses do you tend to have where you live? By me its a mix of tight parking lot and then a race course with cones and a reduced track (ie the twisty back part with the timer before the long straight).

With a 1500 in a parking lot course I tend to stay in 2nd for all but the tightest turns relying on the monster torque from that 1500 For the track one needs a mix of 2nd and 3rd.

Have you done an evaluation of the gearing for your car to better understand the shift points relative to your overall set up?

I used this site: http://www.tremec.com/calculadora.php to generate the images below.

 

[fiatfactory]

9/53 is very short...

PCD of the mounting bolts on the ring gear is different four to five speed....can't recall the actual measurements offhand though

Pinion shaft is different, 4 speed has a circlip groove to retain the bearing at the non pinion end, 5 speed shaft is longer with a spline (or keyway) to retain fifth gear and a thread at the end for the retaining nut.... by you picture the pinion shaft (also the gear cluster shaft) is a five speed item for a splined fifth gear.

SteveC