Higher RPM Tach gauge...

[3rzrunner]

Hey guys. Been away for a while as the runner has been sitting while I gather all my needed parts for the engine build.

I have somewhat of an odd question.

Is there a tach that I can easily drop in that maintains the original cluster and has a higher max rpm reading? Ours currently goes to 7. I was looking for something that will have divisions up to 8K or 8.5K...

Thanks !!

 

[3rzrunner]

Bumppp

 

[UnderFire]

I can't think of anything off the top of my head. Only possibility I can think of is a 3UZ powered Lexus, but I don't know what the factory redline would be.

Sent from my JSN-L23 using Tapatalk

 

[jross20]

Why do you want to do that? :snacker:

 

[phattyduck]

There probably isn't an off-the-shelf option available. If you can get a custom gauge face made, you can probably tweak the response of the tach to match it by modifying some resistor values on the tach driver...

I have previously modified a tach to respond to a different voltage level, the frequency response is probably also modify-able...

Camry tachometer testing - YouTube

-Charlie

 

[APhelps]

I wonder if you could use something like a gauge from a 93+ Mr2 Turbo. You'd need to find out the voltage going into the cluster so you can determine where the tachometer is and go from there. Without really looking into it i believe the voltage is what determines the speed at the tach.

 

[phattyduck]

I wonder if you could use something like a gauge from a 93+ Mr2 Turbo. You'd need to find out the voltage going into the cluster so you can determine where the tachometer is and go from there. Without really looking into it i believe the voltage is what determines the speed at the tach.

There will be an IC on the tach driver board that converts RPM pulses (one per spark plug firing, generally) to a voltage that drives the needle. Newer vehicles than a 3rd gen will use stepper motors and microcontrollers, usually just sitting on the CAN bus (no dedicated tach wire).

-Charlie

 

[gamefreakgc]

That's a tricky one. I'm not aware of any tachs that can be swapped in and chances are it'll cause a headache for the ECU with the signal. Not like 2nd Gens where the tach is literally just spun by a cable. Or maybe that was the odometer.

I'm assuming you have a standalone since that's the only way to spin that engine higher than 6K or so. Why not just use the tach output signal and just replace with a gauge pod or try any retrofit one into the existing 4Runner's gauge cluster?

 

[APhelps]

There will be an IC on the tach driver board that converts RPM pulses (one per spark plug firing, generally) to a voltage that drives the needle. Newer vehicles than a 3rd gen will use stepper motors and microcontrollers, usually just sitting on the CAN bus (no dedicated tach wire).

-Charlie

gotcha. Yeah its certainly not going to be a trivial task and one that's going to require a good bit of leg work to do.

The CAN bus is an interesting thing, not overly complex (if you ask me) but definitely not as easy as the old school way.

 

[3rzrunner]

Why do you want to do that? :snacker:

in the process of building my 500hp+ turbo 3RZ. I would like to redline at 7500-8k, shift at 7k.

 

[3rzrunner]

That's a tricky one. I'm not aware of any tachs that can be swapped in and chances are it'll cause a headache for the ECU with the signal. Not like 2nd Gens where the tach is literally just spun by a cable. Or maybe that was the odometer.

I'm assuming you have a standalone since that's the only way to spin that engine higher than 6K or so. Why not just use the tach output signal and just replace with a gauge pod or try any retrofit one into the existing 4Runner's gauge cluster?

yeah, I haven't seen much that can be either glued overtop the stock face or swapped in. was just looking for an idea before considering more extreme options.

I have a Haltech elite 1500, I have thought about it but also want to retain some of the stock interior look, plus I want to be shifting around 7K, once in a while be able to hit 7500-8K....
as well as my double pillar pod is already going to be full with boost+AFR..

 

[Kanoe]

in the process of building my 500hp+ turbo 3RZ. I would like to redline at 7500-8k, shift at 7k.

Holy Sh!t. I hope you will be sharing some of that with us!

 

[UnderFire]

in the process of building my 500hp+ turbo 3RZ. I would like to redline at 7500-8k, shift at 7k.

That's a whole lot of RPM for an RZ. Better be doing a lot of valve train work my man. Bust out the big wallet lol.

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[jross20]

That's a whole lot of RPM for an RZ. Better be doing a lot of valve train work my man. Bust out the big wallet lol.

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Isn't that the 4 cylinder?

:shocked:

 

[3rzrunner]

Holy Sh!t. I hope you will be sharing some of that with us!

For sure. Here is a few teaser pics for now :bounce:

 

[3rzrunner]

That's a whole lot of RPM for an RZ. Better be doing a lot of valve train work my man. Bust out the big wallet lol.

Sent from my JSN-L23 using Tapatalk

Yup, its getting some decent valve train parts so I hope it will hold up lol.
-Brand new Toyota head
-Stage 2 LCE cam set
-Stage 3 port and polish
-Combustion chamber polish
-Supertech 75lb double valve springs/ titanium retainers / hardened keepers/ shim over bucket conversion.
-Ferrea SuperComp+ 1mm oversized valves
-Adjustable cam gear...

 

[UnderFire]

Yup, its getting some decent valve train parts so I hope it will hold up lol.

-Brand new Toyota head

-Stage 2 LCE cam set

-Stage 3 port and polish

-Combustion chamber polish

-Supertech 75lb double valve springs/ titanium retainers / hardened keepers/ shim over bucket conversion.

-Ferrea SuperComp+ 1mm oversized valves

-Adjustable cam gear...

Impressive. That things gonna be able to put any 3.4 to shame when you're done with it. I want to do a similar build with ITBs eventually, not gonna turn that much RPM though. Slowly piecing it together, have the all the easy parts (stock stuff) the stage 2 cams and a megasquirt already but it's still quite a ways on the back burner.

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[3rzrunner]

Impressive. That things gonna be able to put any 3.4 to shame when you're done with it. I want to do a similar build with ITBs eventually, not gonna turn that much RPM though. Slowly piecing it together, have the all the easy parts (stock stuff) the stage 2 cams and a megasquirt already but it's still quite a ways on the back burner.

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I hope so. Plan on around 20-25psi at 500-500whp.
ITBs!? Damn nice! Planning to do an all motor build with them?
Which stage two cams did you end up going with?

 

[phattyduck]

If you can get a replacement gauge face done, that's the hard part... Maybe a a place like Gauges, Custom Gauges, Tachometers, Speedometers, Shift Light, Pod could do the gauge face for you?

(heck, if you get that done, I can probably modify the tach driver to match the new gauge calibration)

OR, if you are really careful, use a 6-cylinder tach driver board on your 4-cylinder signals. When your engine is spinning at 6k rpm, it will show on that tach as 4k rpm. Get the gauge face to match that and you will be golden (no electrical modifications necessary).

-Charlie

 

[gamefreakgc]

Isn't that the 4 cylinder?

:shocked:

The 3RZ's can support crazy amounts of boost. 500 HP at the crank pushing 8K RPM's really isn't that far off. That's about ~425 RWHP.

For example, my engine puts out somewhere around 270 RWTQ at 5500 RPM's. That's about 282 RWHP. If I was to raise the redline from 5500 to 8000 RPM's, the same engine would make 411 RWHP assuming I can keep the same torque levels (which a S/C can't). HP is just a calculation of Torque and 5252 RPM.