gear ratio for 720

[nissan720]

what is the rear end gear ratio for a stock 1984 nissan 720 with a five speed tranny?i want to change mine to get off the line better.what is recommended.details about the motor 9:01 compression,weber 32/36 carb,competition cam,pacesetter header,magna flow exhaust,msd ignition,tirs size 225 55 16 on centerline rims.standard cab

[izzo]

what is the rear end gear ratio for a stock 1984 nissan 720 with a five speed tranny?i want to change mine to get off the line better.what is recommended.details about the motor 9:01 compression,weber 32/36 carb,competition cam,pacesetter header,magna flow exhaust,msd ignition,tirs size 225 55 16 on centerline rims.standard cab

 

should say on the fender tag i think

[datzenmike]

Look on the inner pass side fender under the hood hinge. Near bottom left is TRANS/AXLE and across on far right it might say HF38. H is for solid axle with removable third member or banjo style, F I think is the ring gear size 190mm, 38 is the ratio 3.889. An HF41 would be 4.111, HF43 is 4.375 and so on.

 

 

The '84 720 gas and diesel came with H-190 3.364, 3.7, 3.889, and 4.375.

 

All 4X4s used the C-200 axle and 4.11 ratio. The C is for the Salisbury type differential.

 

 

 

.

[Zlich]

Mines HE38 Whats the E stand for?

[datzenmike]

I guessing that

E=180mm

F=200mm

 

 

HG46.... this was an H233 so...

 

G=233?

[Zlich]

hmm thatd make sense I suppose. are there any aftermarket gears for nissans? or is it mostly just what you can find in other 720's?

[Zlich]

wouldnt mind changing out my gears

[ggzilla]

HE38 = 3.889

 

CA - CA200

HD - H190

HE - H190

HF - H190A

HG - H233

http://datsun1200.co...itle=Diff_Codes

 

to get off the line better.what is recommended

To get off the line better, the steepest ratio possible is recommended. 320 pickups had the H190 gear ratio of 5.125 and you can swap the center pumpkin into a 720 H190 housing

[Zlich]

What does the number before the gear ratio mean? FS5W71B

[datzenmike]

Transmission.

 

F.... floor (shift) R would be remote (column) shift

S... Special over drive top gear. No S indicates top gear is direct drive.

5... number of forward gears

W.. Warner synchros. C= steel (competition) synchros

71... distance between main and counter shafts in mm.

B... Shifter type. There are A and C types.

 

 

This does not mean the FS5W71B is exclusively a 720 transmission. The 71B was also used on L, Z, SD, and CA series motors by changing the front care bolt patterns.

[ggzilla]

Read the aluminum tag. It says "Trans." right before FS5W71B. It originally came with a Floor Shift 5-speed.

[Zlich]

Oh alright thanks I was curious about that.

[_chiefjt]

Wouldn't a 5.125 be too high. Your going to be shifting all the time because the rpms are gonna be redlining so fast. I think the best one would be the 4:1 or 4:3. That's what I'm gonna go with. Unless your just straight racing I guess that would be fine. My dad tried this so this is where I got my info from. And he had a '83 720. He raced but only the people who mattered back on Guam. Thats where I'm from. But sorry for the long talk just thought you should know why I say this. I plan on doing the same thing but run 44mm mikunis, headers, rear end and maybe a cam. Don't know yet. My dad didn't and he ran like 12-13sec.

[ggzilla]

Yes, that's the point. It accelerates faster, so shifts need to be done sooner. The question was how "to get off the line better". 5.1 will take off quicker, pull hills from a stop more easily, and haul heavy loads with less engine strain. But it comes with downsides on the top end.

 

For the 90% of us that want more leisurely driving, some middling gear ratio is more comfortable. Stay longer in each gear. It's all a tradeoff - quicker but noisier? Quieter but slower? More top speed but slow accleration? More acceleration but lower top speed? With the 5.1 gearing it will top out about 70 mph depending on tire diameter.

[Zlich]

What kind of gearing would be good for 32" or 33" tires?

[ggzilla]

Define "good". Do you want faster acceleration? Or more leisurely cruising? Or something in between?

[Sealik]

What kind of gearing would be good for 32" or 33" tires?

 

With those size of tires/weight of truck......at least 4.11.................or 4.38

Did you calculate your rear diff ratio yet?????????

[Zlich]

Define "good". Do you want faster acceleration? Or more leisurely cruising? Or something in between?

good gears for offroading but I want to still be able to get to 60-70mph on the highway.

Sealik not yet I will do that tomorrow and Ill post it on my emission post.

[ggzilla]

5.1s are good for offroading and it'll do 70 mph with those tires.

[Zlich]

would I have to shift alot? probably not cause they are bigger tires right?

[ggzilla]

Taller tires are like overdrive, except they make the vehicle harder to get going in the first place. Datsun used 24 to 25" tall tires with the 5.1 gears.

 

Shift alot? Naw, just shift 3 times to get to 70 mph. Once more to reduce revs if you want to.

 

For rock-crawling you want the lowest gear possible. What kind of off-roading you plan on doing?

[Farmer Joe]

i have no idea why anyone would want to use 5.12s....

 

with a 4wd on 33s, id have to say 4.37s would be awesome. 4.10s would work in a pinch. toyota 4x4 pickups usually have 4.10s, and most of the time do fine with 33s.

 

does your 720 have the z24? you never mentioned.

[Zlich]

farmer joe yes I have a z24.

ggzilla Im planning mostly mudding and trail offroading not much rock crawling but being able to go up hills with ease would be good to.

And for the gearing could I look at gears from toyotas aftermarket wise? Like are the toyotas and nissan mostly interchangeable for parts (steering parts suspension gearing axle stuff)

[Sealik]

I have 4.11s in all my trucks.......in 4L/bull low.... pretty much climb any hill.......good torque

Can crawl slower than Grandma with a cane, if need be..... ;)

With 30 inch tires...it's 2500 RPM in 5th at 60MPH

[Zlich]

thats not bad. ever go any bigger with tires? I also wouldnt mind my speedometer being somewhat accurate too. or atleast 5 to 10mphs off.