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urimashe

rpm's too high?

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hey guys, quick question, 27-29 hundred rpm at 65 ish on the highway with 31 inch tires (235 are the stock size suppose to be on here) normal for the tire size? its a manual tranny, 4wd system, not engaged of course.

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I don't have a manual, but nothing going wrong with your truck can affect your cruising rpm's. How is your gas mileage?

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Yeah, that's normal. These trucks game geared low from the factory. Of course, when there were allot more places with 55 mph speed limits so the gearing worked well for that...

The 97+ vg33 transmissions were geared a little higher, swapping to one of those will give you ~240 rpm drop at 70 MPH
Also all 2wd transmissions were geared a little higher as well.

 

My goal, one day, is to see if I can just swap the higher 5th for highways use and keep my lower gears low.

FS5R30A 87-95 4x4

1st gear 4.061

2nd gear 2.357

3rd gear 1.490

4th gear 1.000

5th gear 0.862

 

97+ vg33 FS5R30A and all 2wd trucks
1st gear 3.580

2nd gear 2.077

3rd gear 1.360

4th gear 1.000

5th gear 0.811

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EDIT: some of the older cars with FS5R30A transmissions even came with 0.711 5th gear(like 1989 300zx turbo). This would be a ~525 rpm drop at 75 MPH... Now that sounds pretty worthwhile for keeping the RPM's down on a 200HP vg33+ pathfinder. that has the torque to drive a tall gear like that down the freeway running 2500 rpm @ 75mph or 2100 rpm @ 65mph...

Thank you for you question, the little research that I did to make this EDIT gave me some good ideas. :)

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Well your welcome to that. would a 97 vg33 4wd tranny fit a 95 vg30 pathy 4wd? or would it require some modifications?

 

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Yes it would fit. The only thing I had to do to put an 02 xterra (also vg33) transmission in my 94 was swap the sub harness because the xterra one had a different plug at the engine bay side...Just unplugged it from the old trans sensors and plugged it into the new ones and it was good to go.

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Bolts right on, my wife's 93 is running one of the newer transmissions. Her tires are smaller than my 89's (correct speedo gear installed in both trucks) and she turns the same RPM on the highway as mine does.
But If I get one of them .711 5th gears out of a z31 T I'll be the one turning lower RPM :)

Edited by MY1PATH

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I don't get why Nissan would want to put such a low ratio in the older pathys, the fact that they changed it in 97 makes me think they had a "My Bad" moment.

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Not at all! They had a "Oh, your driving these to the mall, I thought they'd be used on the farm and trails" moment.

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My 88 auto with 31s at 65 I'm doing about 2750, at 3000 rpm I'm doing around 70

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The autos got .694 OD gears. When the TC locks up you can cruise at pretty low RPM. But auto's are generally geared higher because when the TC is unlocked you get allot of RPM slip.

The gear ratio change was not really a My bad moment. It works fine for 55 mph and IIRC back in 1987 that was the speed limit most places.

 

Also consider, 150 HP pushing 4000lbs + whatever you have inside it and whatever you may be towing. You may want that extra RPM (unless of course your just taking it to the mall)

Me on the other hand, I'm putting out the same power as a Supercharged Frontier and I've been 8,525 lbs on the scales and still got 18 MPG. So I've got the HP and Torque For some taller gears and now I want em...

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And, on the other other hand. I have no upgrades in the engine, but do run 33's. I really enjoy the low gearing out on the trails and around town. No complaints here.

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And, on the other other hand. I have no upgrades in the engine, but do run 33's. I really enjoy the low gearing out on the trails and around town. No complaints here.

Yeah, they make to do with 33's it also brings the RPM's down on the highway. :)

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my 87 hardbody auto with no OD and 4.62 gears was turning about 4000 at 60MPH it was crazy

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^ Reminds me of my '87 too. Spinning almost 5k for hours doing 75-80mph on a 250k mile engine made me nervous but she never skipped a beat!

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alright, so I think I have a leaking manual tranny, ive been cheaking engine oil and its not going down at all. I have oil driping on to the exhaust pipe that runs under the engine and tranny, to me that seems like a fire hazard, do you all think its the tranny? or perhaps there is a pin hole in my rubber brake likes that squirt exhaust during hard breaking.

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I swear the last time I drove my truck (Xterra auto with 33's) just a few days ago, the RPMs were somewhere around 1500-1700 @ 60mph. I just remember it being really low cause I was comparing it to my Subaru that does 60 @ 2550 and 70 @ 2975'ish

Edited by silverton

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I don't get why Nissan would want to put such a low ratio in the older pathys, the fact that they changed it in 97 makes me think they had a "My Bad" moment.

The larger displacement with more HP and torque would have something to do with that, as well as the speed limit and realizing that people weren't using them like trucks.

 

B

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I had to check mine out this morning on the way to work. 65 @ 2500 rpm. My 33x12.50s should be on my doorstep in the next couple of days. I am curious to see the difference.

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33s will lower the rpms. When I run my 33's I have rpms like silvertons. It will not make the mileage any better though.

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Mine seems high,but I get great gas mileage on highway. 60 mph at 3200-3500, and 4k at 75. Its all stock as far as I know and get 21-22 mpg. City is sad tho, I get 15 after my ecu reset.

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Yeah, larger dia.= lower RPMs. Just curious about bigger footprint/mileage/power factor. I get about 17 around town and about 19-20 on the highway. I am sure it will go down but don't know how much.

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Mine seems high,but I get great gas mileage on highway. 60 mph at 3200-3500, and 4k at 75. Its all stock as far as I know and get 21-22 mpg. City is sad tho, I get 15 after my ecu reset.

 

That's four cylinder revs right there! Does your truck have the ever so rare and not so sought after KA? I saw an Xterra with a KA in the junkyard once, I had to do a double take and look at the data plate to make sure that's what was meant to be in it!

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Nope its a v6. It was a granny car before I got hold of it, so I think its stock. But I get good gas mileage, so I ain't complaining.

 

Aren't the KA's the 22re of Nissan's?

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Nope its a v6. It was a granny car before I got hold of it, so I think its stock. But I get good gas mileage, so I ain't complaining.

 

Aren't the KA's the 22re of Nissan's?

 

Yes, in terms of Mainstream 4cyls found in almost every nissan... that's the KA.

In terms of 4 banger modding its kind of a tie, lotta cars that came with KA's got modded with KA's but the SR20 also took a popular seat in the 4 banger modding crowd and is a very common Nissan engine swap

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