Tachometer - How To Add It

[shibs]

I want to add a tac to my toyo camper, anyone had any success in adding one? What parts do I need?

[zero]

I want to add a tac to my toyo camper, anyone had any success in adding one? what parts do I need?

I added tachs to my 1988 Toyota RV and my 1978 Toyota RV. Easy to do with a gas engine. Just two wires that hook to the ignition coil My tachs cost $19 each from Ebay.

[5Toyota]

my dolphin came with an add on tac. I went to replace the plug wires and found it had an induction clamp on the plug wire. just bolted on the plug wire. never saw one like that but it works. I checked and it is for the tac.

[shibs]

JDE,

hot dog, that is simple enough, I just bought the ebay tach,

Thanks a bunch!

5toyo, I remember buying a tac like that for my mower/powerwasher many moons back when I lived in NE. I will check if they sell one like that that runs off a batt,

I want to check my rpm in 3rd gear at 60 mph and 65 mph.

I guess I could calculate it using gear ratio and wheel diameter...

[Derek up North]

I guess I could calculate it using gear ratio and wheel diameter...

There are many online calculators.

[shibs]

^{Found one:}

^{22re with 3.9 ratio rear}

^{3931 rpm @ 60 mph in 3rd}

^{4259 rpm @ 65 mph in 3rd}

^{This is well below the 6500 rpm REDLINE on the engine}

^{http://spicerparts.com/calculators/engine-rpm-calculator}

^;-)

[Derek up North]

I'm not sure what numbers you used, but apparently not 3.9, 25.5 & 60.

[zero]

^{Found one:}

^{22re with 3.9 ratio rear}

^{3931 rpm @ 60 mph in 3rd}

^{4259 rpm @ 65 mph in 3rd}

^{This is well below the 6500 rpm REDLINE on the engine}

^{http://spicerparts.com/calculators/engine-rpm-calculator}

^;-)

The calculator only works for manual transmissions or with automatics in "lock-up" mode. NOT going to work with four-cylinder Toyota RV with an auto trans. No accounting for torque-converter slip that can be up to 15%.

By the way, are you saying you've got a 3.90 to 1 rear? That's kind of rare in a Toyota RV. Toyota only offered that ratio for manual trans setups for a few years in the mid-80s. All else had a 4.11 to 1 ratio or a 4.10 to 1 ratio.

[Derek up North]

All else had a 4.11 to 1 ratio or a 4.10 to 1 ratio.

A few later (V6) motorhomes came with a 4.30:1 ratio. Also 195R14 tires. Possibly only Winnebagos. I guess it just depended which options were ticked off on the list.

[zero]

A few later (V6) motorhomes came with a 4.30:1 ratio. Also 195R14 tires. Possibly only Winnebagos. I guess it just depended which options were ticked off on the list.

If that is true seems it would have be after 1991. I have all the factory Toyota cab & chassis books up through 1991 and the 4.30 to 1 rear-axle ratio was not an option with the V6 rigs. Neither were bigger tires. Chassis's VZN85L-TRSREA6/VCN85L-TWSREA6/VZN85L-TWSREA6/VZN95L-TWSREA6/VZN85L-TRMREA6/VZN85L-TWMREA6/VZN95L-TWMREA6

VZN85 with a wheelbase of 112.2" VZN95 with a wheelbase of 137"

Tires for all: Single rear wheel - 185R14LT 8 PR, dual rear wheels - 185R14LT 6 PR

Transmissions: 5 speed manual with 3.83 to 1 ratio first gear and .83 overdrive in 5th

Automatic 4 speed with 2.80 to 1 ratio in first, and .7 overdive in 4th

Rear axle ratio - 4.10 to 1 for all versions

Brakes- 10.1" front disk for single wheel, 10.3" front disk for duals

10" rear drums on both versions

Maybe some companies changed the gearing and tires themselves.

[Derek up North]

G284 coded 4.30:1 Factory ratios. Unless Winnebago sourced Toyota stickers.

[zero]

Yes, and that sticker indicates a model year of at least 1992, As I stated earlier, Toyota did not offer the 4.30 to 1 ratio up though 1991. 1992 or 1993 may have seen some coroporate changes. I don't have the factory books for those years.

[Derek up North]

And as I said: "A few later (V6) motorhomes came with a 4.30:1 ratio. Possibly only Winnebagos."

And actually what you stated was: "All else had a 4.11 to 1 ratio or a 4.10 to 1 ratio."

[shibs]

I messed up the tire size,

using 24.5 inch for tire

3.9 for rear

and 60 mph

60 mph - 3209 rpm

65 mph - 3477 rpm

I just wanted approx. I am going to drive without the OD, here around where I am west MI, most hwys are rolling hills, so keeping the OD off helps a bunch to keep the speed steady.

22RE and 3VZFE has a redline at around 6500 rpm, correct?

[shibs]

And as I said: "A few later (V6) motorhomes came with a 4.30:1 ratio. Possibly only Winnebagos."

And actually what you stated was: "All else had a 4.11 to 1 ratio or a 4.10 to 1 ratio."

4.3 ratio, hmm, did they start making the 92s heavier?

[Derek up North]

Well, the typically used 185R14 tires are ~25.5" diameter (depending on brand, wear and tire pressure).

I've driven 4.10:1 and 4.30:1 V6s back to back, and if I could do it blindfolded, I can honestly say I'd be hard pressed to tell them apart. Only a ~5% change.

Those who go from 4.10:1 to 4.56:1 (~10%) claim to notice it. Going from 3.90:1 to 4.30:1 (~10%), you might too.

Though you might well drive up steep hills in 1st, I doubt you're ears would let you get very near 'redlne' (whether 6000 or 6500rpm) for long before easing off.

[zero]

4.3 ratio, hmm, did they start making the 92s heavier?

A 20-21 foot Toyota RV really needs a 4.56 to 1 rear-axle ratio to make good use of any overdrive. Toyota never offered that ratio as a factory option. Probably because Toyota never engineered a truck to carry such a load and with as much wind-resistance as an RV on a full-time basis. Datsun/Nissan had 4.30 to 1 rear-axle ratios long before Toyota in their cab & chassis rigs.