"diesel" t-case gears

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ss30378

Active member
I inquired to sumo gear about a t-case gearset with a 1:1 high range to help get the RPM down for the diesel folks.

I got a response that if the market is good enough to support 50 sets being made they would do it.  Would any of you be interested in such a set?  What low range ratio would you be into?  
 
I would be perhaps..........

Having said that.......what is the quality of Sumo like? I had a set of TG 4.9's and I sure didn't like the growling noise I got with them. My zuk sounded like a tractor with them. I DID like the low range of the 4.9's however.

I would be happy with the equivalent low gearing of the 4.9's and even lower if that's the consensus of the other 49 guys choices.

Did you ask what the cost would be?
 
Spokerider said:
I would be perhaps..........

Having said that.......what is the quality of Sumo like? I had a set of TG 4.9's and I sure didn't like the growling noise I got with them. My zuk sounded like a tractor with them. I DID like the low range of the 4.9's however.

I would be happy with the equivalent low gearing of the 4.9's and even lower if that's the consensus of the other 49 guys choices.

Did you ask what the cost would be?
Click to expand...

Sumo quality is far superior.

I would love a 1:1 high, 4.9 low. If, I still had a diesel in my Zuk that is.
 
He didn?t say what the cost would be so I responded to the email with what the estimated cost would be and if a 1:1 high with 4.x low range could be made.  We will see what they say!
 
ss30378 said:
He didn?t say what the cost would be so I responded to the email with what the estimated cost would be and if a 1:1 high with 4.x low range could be made.  We will see what they say!
Click to expand...

Or........maybe ask what the "low" choices would be that we could decide upon / choose, keeping with the 1:1 high.

There are other zuk diesel enthusiasts that may be reached on Pirate, vwdiesel.net, maybe IH8MUD, etc.......
 
Considering how many people have done diesel conversions 50 pieces doesn't sound like that many.  50 pieces at say $350/ea wholesale is only $17.5k.  Not trivial but not really that much if you're running a parts business.  It might be worth approaching some of the aftermarket dealers about this. (Acme, Roadless Gear, ZOR, etc.)


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Sumo does seem to have a general interest in running a 1:1 high range setup.  They responded that they would only sell to vendors so it looks like I can?t get the cost out of them.

I agree from an automotive manufacturing perspective a 50 piece run is pretty small compared to many batch requirements.

I also asked if there were any machining limitations for the low range with running a 1:1 high, I?m interested to see what they say on that.

I know ZOR already sells sumo gear sets and I think someone selling the diesel swap conversions like acme would be the best to market these.
 
Response from Greg Pfeiffer this morning:

Good Morning Steve,

Both Zuks and Petroworks would be outlets to carry this option and I can reach out to both once I look into the feasibility of the gear ratio.

To answer your question, yes the low range ratio is tied to the hi range ratio.  The hi range ratio is created by the input rotating the large side of the idler and that in turn rotates the hi speed gear.  To achieve 1.0:1.0 the number of teeth on the input and hi speed gear have to match.  When the transfer case is shifted in low that ratio is created by the input rotating the large side of the idler and the small side of the idler rotating the low speed gear.  So when you have a 1.0:1.0 hi range the ratio the ratio between the input and large side of the idler make up half the ratio for the low range side which limits the options.  This is what I will need to study in order to see if it is possible to achieve both ratios as requested.

Best,
Greg
 
I still think the 1:1 transfer case will help with highway high speed driving but will hamper low speed first gear driving

In effect, it will feel like starting out in second gear in the transmission....

I think the second half of the solution is to lower the first gear ratio in the transmission as well as the 1:1 transfer case for high speed.

just a humble opinion....
 
Ack was researching the whole custom 1:1 gears a while back as well when he was working on his TDI swap. As I recall, he ran into the same issue with the gearing. Due to how the gears work inside the case, you are very limited to what kind of low range you can run.

There is a guy in California that was going to have some custom 5th gears made to lower the RPM, but I don't believe it ever happened.

I myself, even though I did the 1:1 tracker tcase swap, found that I never actually even needed it, and didn't like it with 3.73's, and 33's. I ended up putting 5.13's in the diff to fix it. It was a good combo, but I wouldn't do the 1:1 again, except for a daily driver that sees a lot of highway speeds.
 
I think this would be great. I have 1:1 high range in my sidekick and 3.73 diffs. Even against a strong headwind going uphill I don't find it needing more reduction. I'm actually trying to lower my rpm more. Doesn't feel like starting in 2nd either. It feels better than the original 8v.
 
My last samurai had a 1.6na vw diesel on stock gearing with 32? tires.  I felt like I was pushing past the happy cruising rpm zone at around 60-65mph.  That would be my rationale for going to the 1:1.  The tdi?s have quite a bit more low end torque than my little 1.6 had so I don?t see an issue with what I?m looking for.

My old 2.5l wrangler on stock gears with 4.10 diffs and 33s had excellent street manners with its 1:1 t case.
 
Well, lets see what Sumo comes up with for low gearing, with 1:1 high gearing.

With stock TC gears and 85 series 16" tires......I like the rpm gearing on pavement. If anything......I could go 100 or 200 rpm lower in high gear. But......keeping up with traffic flow in either 4th or 5th gear, at 2400-2900 rpm ain't bad.......it keeps me in the power range when I need to up-shift, so I don't loose too much boost. 
Low gear in my setup is great for logging road travel, but not great for technical terrain or going very slow over the rough. The 215 / 85 / 16's make my low gear higher than a stock zuk with 215/ 70 /15's.

Question.........could suzuki have installed TC gearing that would have lowered low range more than it is, and keep high range gearing as is??
 
So I ran around with the googler a little bit....

Suzuki samurai:
Transmission​
Type5-Speed
ClutchDry, single disc, diaphragm spring
Gear Ratio
1st3.652
2nd1.947
3rd1.423
4th1.000
5th0.795 (0.865 after 1988.5)
Reverse3.466
Transfer Case​
TypeManual
Gear Ratio2.268 (low) 1.409 (high)



Geo Tracker:

Gear Ratio (Manual)
1st ? 3.65
2nd ? 1.95
3rd ? 1.38
4th ? 1.00
5th ? 0.86
Reverse ? 3.67

Transfer Case
TypeManualSame
Ratios1.82 (Low) 1.00 (High)Same


Suzuki Vitara:

DrivetrainSuzuki Vitara 2 DoorSuzuki Vitara 4 Door
Transmission Type5-Speed SynchronizedFour-Speed with Overdrive5-Speed Synchronized4-Speed with Overdrive
Clutch TypeDisc-Disc-
Torque Converter-Lock-Up-Lock-Up
Gear Ratios:
   1st3.6522.8263.6522.826
   2nd1.9471.4931.9471.493
   3rd1.3791.0001.3791.000
   4th1.0000.6891.0000.689
   5th0.795-0.795-
   Reverse3.6702.7033.6702.703
Transfer gear ratios
   Low (4WD)1.8161.8161.8161.816
   High1.0001.0001.0001.000
Differential Ratio4.6254.8754.6254.875








Conclusion:
I'm right out to lunch in thinking there is much of a difference in transmission ratios that have 1:1 transfer cases or not.....
 
Definitely interested, I was actually just commenting on another guys post on the Suzuki Diesel page. Really curious to see if you make any headway with this!
 
Could someone dumb down this whole 1:1 gearing thing for me? What are we trying to achieve? What is the stock ratio and what repercussions are we suffering from with it?

On my ABA swap, I find that it "feels" like I have to rev the engine 1,000 rpm higher than I normally would in a golf/jetta to be in the same powerband. Is this what you are referring to?

Thanks
 
stuntnuts said:
Could someone dumb down this whole 1:1 gearing thing for me? What are we trying to achieve? What is the stock ratio and what repercussions are we suffering from with it?

On my ABA swap, I find that it "feels" like I have to rev the engine 1,000 rpm higher than I normally would in a golf/jetta to be in the same powerband. Is this what you are referring to?

Thanks
Click to expand...

Essentially the idea is to increase the gearing, so as to drop RPM's.
The stock samurai transfercase has a 1.4:1 high range, so even while cruising down the highway, there is still a bit of reduction coming from the case itself.

On an early Samurai, 5th gear is .795:1. So .795x1.4x3.73(factory diff ratio), which equals a final drive of 4.15:1

I'm not totally familiar with VW transaxles, but from what I'm seeing, 5th gear is probably around a .8:1, with a ring and pinion of 3.667, which would give you a final drive of 2.9:1.

With a 1:1 tcase high range, you'd have a 2.96:1 final, pretty close to the VW final.
 
Diesel_Zuk date=1602594708 said:
Essentially the idea is to increase the gearing, so as to drop RPM's.
The stock samurai transfercase has a 1.4:1 high range, so even while cruising down the highway, there is still a bit of reduction coming from the case itself.

On an early Samurai, 5th gear is .795:1. So .795x1.4x3.73(factory diff ratio), which equals a final drive of 4.15:1

I'm not totally familiar with VW transaxles, but from what I'm seeing, 5th gear is probably around a .8:1, with a ring and pinion of 3.667, which would give you a final drive of 2.9:1.

With a 1:1 tcase high range, you'd have a 2.96:1 final, pretty close to the VW final.
Click to expand...

Keep in mind with this, most of us are running significantly taller tires than a stock VW TDI...
30" or 31" would be really great to run in a Samurai with diesel transfer case gears. With 31" or 32" tires in mind, or even 33, a 1.15:1 or 1.2:1 high range to work with stock 3.73 gears would be appropriate even based on the #'s above and what rpm calculations I've made in the past.

A taller 5th gear would be nice, but I would NOT be investing money into modifying the Samurai transmission when 16v 1.6L 2wd Tracker Sidekick SunRunner X-90 trannies are far superior. Keep the gearing investment in the transfer case.


Someone on here years ago had looked into what Suzuki Samurai Jimny diesel models had ran overseas, & I believe some older transfer cases he found had a better high range. 
And the guy on here who just recently got a newer Jimny electronic shifting transfer case with 1:1 high range was really onto something as well.

 
stuntnuts date=1602591218 said:
Could someone dumb down this whole 1:1 gearing thing for me? What are we trying to achieve? What is the stock ratio and what repercussions are we suffering from with it?

On my ABA swap, I find that it "feels" like I have to rev the engine 1,000 rpm higher than I normally would in a golf/jetta to be in the same powerband. Is this what you are referring to?

Thanks
Click to expand...
 
 

Basically, the problem is that the 1.9L TD/TDI engines don't rev nearly as high as the stock 1.3L Suzuki engine.  So unless you have much larger than stock sized tires, the overall gearing in the Samurai is too low, and requires the engine to spin too fast at typical highway speeds.  And if you want to install aftermarket gears to increase the low range crawl ratio, the high range gearing ends up even worse.

Your ABA engine is a better match for the Samurai gearing than the typical ALH or AHU engine use for a diesel swap.  An ALH or AHU is going to produce peak power in the 3800-4000RPM range, while an ABA will peak at 5400RPM.  Torque peak on the diesels is at 1900RPM(!) where your ABA is at 3200RPM.  I can't really find any solid specs on the stock Suzuki G13A engine; but HP peak is likely to be over 6000RPM while torque peak is around 5000RPM.

Gauging by feel is not really going to be a direct comparison though.  The Samurai has far more wind resistance than a VW car, and also more drive train to send power through.  So a given engine will likely need to rev somewhat higher in a Samurai to get the same acceleration it would produce in a VW car.  But not as high as the typical Samurai drive train would get you.


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