Infiniti G20 Nissan Primera Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #1 ·
Has anyone done this yet?

Since I do not see a turbo in the oh so near future, it seems as if the shorter gears in the NX2000 would benefit me greatly. Or, should I say, make the ride more enjoyable!

I am not talking about a tranny swap, just the gears. That way, I would not have to make sure the axles are the right length, etc.

And I did not know if it is possible to take the gears out of the NX for the swap since it has LSD and my G20 does not.

I use to own a '91 NX2000 with similiar mods (Stillen/K&N intake, 2" custom midpipe, Borla rear section and 17 degrees) and loved the "snappy" feel it had when accelerating and can only attribute that feeling to the gearing. And the fact it was a little bit lighter. :cheeky:
 

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #2 ·
ttt

OK, once again.

The reason I ask is I might have access to my old '91 NX2000 tranny that has busted forks, but the gears are all ok. I don't own the car anymore but my father-in-law works at the shop that replaced it for me a year ago and might still have the old tranny sitting in their basement.

I am interested in the gear ratios that the NX has for my NA application. They are shorter as opposed to the longer 1st and 2nd gears in the G20.

Anyone? :beard:
 

·
Registered
Joined
·
5,266 Posts
Sorry NismoPC. Looks like you're gonna have to be the first one to try that. :-\
Don't feel alone. I've yet to hear if anyone's ever put a 2001-2002 P11 variable capacity muffler on a P10. Seems like I'll have to be the guinea pig:depressed . Oh, well, all in the name science I guess.
 

·
Premium Member
Joined
·
4,409 Posts
umm.. 1st and 2nd gear should be the same in both cars, IIRC. It isn't until 3rd that the gearing changes. Also, why would you want the shorter top gears? You will have more than enough power to power through the gears. The only thing that'd change would be higher revs on the highway and stuff. I don't think the gearing is really different enough to create that much of a performance change, if any. But then again, i could be wrong too?
 

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #5 ·
Oh. I just looked at the specs to compare.

Gear..........NX2000........G20
1st.............3.333...........3.063
2nd............1.826...........1.826
3rd.............1.286...........1.207
4th.............0.975...........0.926
5th.............0.756...........0.733
Final...........4.176:1........4.058:1

Maybe this will help. Looks as if 2nd is the only same gearing. I was reading a post a while back on the other g20 forum where I believe Geo chimed in and stated the NX2000 tranny would be a good swap for NA engine, but that the G20 tranny is good for Turbos cause of the longer gears.

So, it is the lower the # the longer the gearing? I probably should know this one, but I am brain fried today from work.
 

·
Premium Member
Joined
·
4,409 Posts
Yeah, the lower the number, the longer the gear. that's weird... i could have sworn the older se-r's had teh same first gear too. DOH!

Also, check this out.. look at the gearing for the 99 p11 http://www.g20.net/g20-1999specs.html
Same as the NX, except for first (shares with the P10).

Then look at the 2000 P11, even different from the 99 p11.
same 1st as NX, different 2nd, NX 3rd gear, P10 4th gear, NX 5th gear, and P10 final drive :confused:
http://www.g20.net/g20-2000specs.html
 

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #8 ·
JustinP10 said:
Then look at the 2000 P11, even different from the 99 p11.
same 1st as NX, different 2nd, NX 3rd gear, P10 4th gear, NX 5th gear, and P10 final drive
That is similiar to what I was thinking of doing. Swapping P10 1st for the NX, leave the 2nd as P10 since it is the same as the NX, P10 3rd for the NX, then leave the rest as P10 gearing for highway driving.
 

·
Registered
Joined
·
306 Posts
gearing



So, it is the lower the # the longer the gearing? I probably should know this one, but I am brain fried today from work. [/B]


Correct on the GEAR ratios, the final drive is the opposite. The higher the number the shorter the gear. i.e. If fifth gear is the same on two cars, the car with a 4.176:1 final drive would rev more on the highway than the car with the 4.058:1 final drive. That is why trailer towing packages on trucks have "4.10" rear ends vs. 3.98, 3.75, etc., it gets them in the the meat of the torque curve faster. You can shorten ALL your gears by 3% by swapping just the final drive from the NX2000. Possibility?

I have seen a formula to calculate all the way out to your tires your rpm at any given speed/gear. Might have been in Car & Driver at some point. With this calculation you can figure out what ratios would put you closer to the torque peak rpm for the speed/gear you are most interested in. Ideal ratios occur when you reach peak HP rpm, shift to the next higher gear, and that gear places you at/near the TORQUE peak. Do your calculations before anything else. This makes swapping JUST the final drive an easy solution because you are not messing with the HP/Torque peaks between GEAR ratios.
 

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #10 ·
Thanks for the info 95Gee20Tee, but the NX2000 tranny I had access to went to the salvage guys.

It was from my old NX2000 when I busted the forks in it. I was gonna rebuild it, but didn't have time to go pick it up from my father in law's shop that he works at, then I forgot to tell him to keep it. So the salvage guys (Sanford and Son - Hehehehe) came by and took it away. ARGH!
 

·
Registered
Joined
·
306 Posts
Couple more gear ratio ideas

A thought of a couple other items about gear ratios:

1) Many manufacturers make their cars with EXTRA tall second gears for minimum 0-60 mph times. If they can reach 60 in 2nd gear, they can reduce the time by .2-.5 seconds. The engineers, who know what gear ratios will work best, are not necessarily for this but they are under pressure from the marketing/sales group that loves the fast 0-60 numbers to BEAT their competition. As you can see, with this attitude, the 2-3 gear shift may NOT be the best combination of HP-TORQUE peak shifting. I am paraphrasing this from a Car&Driver article.

2) You can also change your final drive ratio with your tires! If your stock tires are 195/65R14, than a switch to 205/50R15 is equivalent to a 3.8% shorter final drive. Just going to 195/60R14 is a 3.2% difference. Additional, shorter tires have less rotational mass (quicker to roll) and unsprung weight (better handling). However, this will affect your speedo accuracy as well.
 

·
Registered
Joined
·
97 Posts
Do you guys not read the se-r list? You should. I posted all about this a while back.

I did this a long time ago. All of the gears are the same, NX, SER, B14, B13, P10, you name it. I am currently as of right now driving my car with 1-2 out of something (all the same) and 3-4-5 out of a NX2000 since it is lower. Very nice. Next time I go inside the tranny I plan to put the G20 5th gear back in to keep the RPM's down while cruising, but everything else is staying.
 

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #13 ·
Do you guys not read the se-r list? You should. I posted all about this a while back.
Well lawdydada to you too. Jeez! :p

I've been a member of the SE-R mailing list for probably a good 6 years and sometimes I just get tired of reading through the emails until I see something that is of interest to me. Atleast on the forum, replies are quick and are all posted in one location for me to view at my leisure.

But thanks for the info. I'll go search the archives and look it up. Yeah right search the archives. Hehehe! Haven't heard that one before. :lol:

Some questions though. Why didn't you do
NX 1st,
G20 2nd
NX 3rd
NX 4th
G20 5th

I am still contemplating this gear swapping.

Just curious to what you used for 1st gear as opposed to the NX gearing. The G20 2nd is the same as the NX 2nd, so there wouldn't be much of a change there. Also, your website states the following...

NX2000 LSD tranny and case with SER gears (lower 3,4 and 5th)
Have you changed the gears since then where you put the NX2000 3rd, 4th, and 5th in or did I miss something.
 

·
Registered
Joined
·
97 Posts
The FSM is wrong, or at least wrong per what I have seen. Every single transmission I have seen has 1 and 2 the same. (I should know, I rebuild them all the time.) NX, Sentra, 200SX SER, SER, B13, P10, all the same. 3,4,5 are all lower in the NX/Sentra vs. the P10, but they are the same. Meaning NX, SER, doesn't matter, same gearing, still lower than the G20 stuff, but exactly the same.

So basically there is no option on 1,2 and the only option on 3,4,5 is what is in the SER/NX which is lower.

Oh, and the FSM is wrong about the final drive, too, they are all the exact same no matter what it is in (talking 5 speeds of course).

My current tranny contains doner parts from a P10 non LSD tranny, a 91 SER tranny, and a 93 NX2000 tranny. :)
 

·
Registered
Joined
·
2,120 Posts
Discussion Starter · #15 ·
That's odd, but not surprising. Thanks Jay!
 

·
Registered
Joined
·
64 Posts
JDM Ratios

Just thought I'd chime in here with the ratios we get on the Primeras. Not sure whether you can get hold of one but here it is anyway.

Primera Ratios:
......................SR20DE...........................................SR18Di
...........2WD..................4WD...................................2WD
1).......3.063................3.063..................................3.333
2).......1.826................1.826..................................1.955
3).......1.207................1.286..................................1.286
4).......0.926................0.975..................................0.926
5).......0.756................0.756..................................0.733
R).......3.153................3.153..................................3.153
Final....4.176................4.375..................................3.888

The SR20DE Primeras use the RS5F32A gearbox with the 4WD having an FM43 centre diff added onto it.

I'm not sure about the SR18Di Primeras but I'd imagine the same box.

Looking at the ratios, you have most of them available in the US except for:
1.955 2nd gear from the SR18Di found in the 1.8Ci and 1.8Cu P10s (E-P10). 3.888 final drive ratio found in the 1.8Ci and 1.8Cu P10s (E-P10).
4.375 final drive ratio found in the T4 (4WD) P10s (E-HNP10)

My T4 with stock 195/60/14 tires on is revving at 2976rpm @ 100km/h (62mph) in 5th. Redline (7500rpm) top speeds are:
1st - 62km/h (38mph)
2nd - 104km/h (64mph)
3rd - 148km/h (91mph)
4th - 195km/h (121mph)

Perhaps some of the JDM engine importers in the US have some unwanted T4 gearboxes doing duty as doorstops which you could pillage the final drive ratio from. :)
 
1 - 16 of 16 Posts
Top