Tech article: Installing a monster tach: how-to
05-11-2003, 10:16 AM
#1
Thread Starter
Tech article: Installing a monster tach: how-to
After people ranting and raving at me for over a year about using the stock tach for so long (hey, I wasn't having problems with it) and seeing Mr. S's tachometer installed and working, I decided it was time to step up to the plate. I knew Mopac was selling an AutoGauge 5" tachometer with shift light for $190, and called Lordco to see if it was cheaper. They said it was $350, and with my discount would come down to $230. 
I went back to Mopac. They checked the shelves and said they had 14 units on back order... bad news for me... so instead I pointed to the AutoGauge 5" tach with shift light and memory and asked 'How much?'. He surprised me with the number: $190 before taxes. Woohoo! Evidently the tach with shift light and no memory is only $169, not $189, like the one I picked up. Nice. I think it's worth the extra $20 to have a memory recall on highest RPM reached.
Picture of the tachometer: Top button is for memory recall, bottom button is for memory clear; pressing both buttons allows you to moving the shift point by using the top and bottom buttons as up and down arrows:
The tach and shift light looked so sexy that we couldn't resist trying it out on other things.
Mr. S and I definitely needed to take this picture:
After sobering up, the shift light was test-fit inside the car. I wanted to mount it on the left side of the dash, but unfortunately it wouldn't fit without sitting too high up and entering the visibility zone, which was already hampered by my dual gauge mount. I decided that was unacceptable and, like Mr. S, decided to mount it more centrally in the car. Hey, you've got to reduce polar moment somehow!
This is where test-fitting comes into play. Unlike Mr. S's setup, you can see that the tachometer's visibility is interfered with by moving the steering wheel up and down when it's mounted to the far left. This is not a problem for Mr. S as he's much taller than me and his dash has a different configuration, but it's unacceptable in my case. Plus it interferes with removal of the gauge cluster cover if that becomes necessary.
The shift light itself can be removed from the tach and mounted separately. It comes with a connecting wire about 1' long to mount it wherever you'd like, and a disconnect clip to remove it if you want. I left it on the tach; what's the point of mounting the light stealthily if the tach is on the dash?
Tachometer placed to the far left, steering wheel lowered maximum:
Tachometer placed to the far left, steering wheel raised maximum:
The tach base was moved right until visibility improved in all circumstances.
Tachometer placed more centrally, steering wheel lowered maximum:
Tachometer placed more centrally, steering wheel raised maximum:
Now it comes time to actually begin mounting the tach. The tach is held up by a circular brace or strap that is supported by the pedestal with two bolts. The pedestal itself screws to the dash using two supplied <shudder>flathead</shudder> screws.
Tachometer pedestal:
The tach was left in place on the dash and a bottle of whiteout was used to mark the correct placement on the dash. I don't really recommend this method as you can't get the damn whiteout marker around the tach body and into the little teeny holes. I somehow managed to do it after much cursing. However, it left white marks on the base, which I need to get off there somehow. Orrrr... I could ignore them. Yeah, I'm gonna ignore them
Whiteout marks where the screw holes need to be made:
I used a thinner, sharper screw than the ones provided to begin making a hole in the dash. While it's just regular plastic, due to the location - right under the glass - it's actually quite hard to get those screws in place. Using the starter screw eases the task and makes it less of a chore to thread the supplied screws in. Nevertheless, it took about half an hour to get the screws in place.
Screws being threaded into dash:
After the screws had a thread into the dash, the pedestal base was mounted and tightened firmly.
Pedestal mounted to dash using supplied screws:
Another view of the pedestal mounted to the dash, showing how low it actually sits:
Now it's time to drill a hole in the dash for the gauge wiring. There's a supplied rubber grommet that is designed to cause you the maximum amount of aggravation during install. I used it to size a drill bit large enough to pass 4 12-gauge wires through and mount the grommet, and then began drilling.
Due to the angle of the windshield and the position of the tach mount, the closest I could get to the tach was this location and this angle:
Note that you shouldn't drill too far down, as your heater controls actually reside directly underneath your dash. I drilled very slowly - thanks, Craftsman variable-speed drill!
The completely drilled hole:
After some cleanup, the grommet was installed into the hole, awaiting the tach wires. This is a real PITA to put into place, as the dash plastic is too thick for the grommet's center space to encompass. Thanks to this, I quickly lost the grommet somewhere underneath the dash when the wires were being fed through. Oh well, bye bye grommet.
Grommet installed shortly before going AWOL:
Another view of the installed grommet - too bad it didn't like my car enough to stay awhile, but it looked good while it lasted:
Feeding the wires through was complicated. I taped them all together at the end and used that to go through the grommet at first. It was a tight fit and this is where the grommet decided to make a run for it and vanished into the hole along with the wires, never to be seen again.
The wires themselves tend to get caught on the heater appliances behind the dash. I found it was easier to feed them through one at a time and leave each one hanging under the dash while the next was fed through. Once the grommet was gone there was plenty of room and it was much easier.
Now's where it gets fun. The four wires on the left are the tach wires - green is for tach signal, white is for dash lighting, black is for ground, and red is for +12V switched power. I have all these circuits isolated and labelled already for my other gauges and simply tapped into those. The tach signal was the difficult one.
Tach wires fed through dash, center console piece removed exposing messy wiring everywhere (oh well, it works):
One the 3 simple wires were attached, I had to decide where to get my tach signal from. There's several locations and people espouse each method according to their preference. Some like to get their signal from the blue wire at the gauge cluster feeding the stock tach. Some like to take the feed as close to the ECU as possible, and others prefer to feed the tach signal wire into the engine bay and tap into the distributor directly. I decided to tap off the ECU; who cares what the distributor or stock tach say - it's the ECU that has the final say when the fuel cut comes 'round.
Exposed ECU wiring, B harness unplugged, B15 wire is the tach signal. The green wire at the bottom is the wire for the AutoGauge tach:
A 0.5" section of the wire next to the ECU plug was stripped, the AutoGauge feed wire was stripped, and the the two wires were soldered together and electrical-taped up for protection.
Shot of the completed work:
After this it was a simple matter of putting the tools away, cleaning up, and setting the # of cylinders the tach expects. In order to do this, before you turn the car on, hold down the top 'recall' button. Turn the car on, and the tach will jump from 2k to 3k to 4k spending ~2 seconds at each RPM. 2k = 4 cylinder, 3k = 6 cylinder, 4k = 8 cylinder. I set it to 2k (it was set to 4k previously) by releasing the button when it reached the 2k mark. A second later the tach zeroed and it was ready to go.
A quick check of the systems and I started it up.
Tach functioning correctly:
The shift point came preset at 6500 rpm. I set it low - about 3k - and test-revved it to see how the shift light looked. DANG BRIGHT!
Holy momma that hurts my eyes:
Final thoughts: Basically, once the shift light comes on, you're blind. You can't see anything else until you shift because that light is pointed directly at your eyes.
Getting used to the tach is hard after driving my car for about 6 years with it on the left of the cluster. I caught myself watching the stock tach when taking it to redline, and right now, the shift light more startles me than makes me want to shift. I think once I get used to it it'll be very, very helpful, but right now it's just confusing.
Cool things: I can set the shift point while driving; the $169 tach won't let you do that. I can also check my peak RPM level while driving and reset it on-the-fly. Plus - damn, does the tach look sexy! It has a very nice finish to it, and the buttons don't feel too cheap. The wires are nice and flexible, not some cheap crap, and the rubber bits are flexible and soft - quality stuff.
Not-so-cool things: The ugly yellow dust cover for the shift light. That thing is so bright it screams 'look at me!'. I plan on taping it up or something to make it darker and less noticeable. Also, the tach doesn't always remember the shift point correctly between driving sessions, meaning you should set it each time you drive the car. That's going to become annoying very rapidly, but that's why I paid only a little over $200 after taxes and not $500 or whatever for an AutoMeter monster tach.
I went back to Mopac. They checked the shelves and said they had 14 units on back order... bad news for me... so instead I pointed to the AutoGauge 5" tach with shift light and memory and asked 'How much?'. He surprised me with the number: $190 before taxes. Woohoo! Evidently the tach with shift light and no memory is only $169, not $189, like the one I picked up. Nice. I think it's worth the extra $20 to have a memory recall on highest RPM reached. Picture of the tachometer: Top button is for memory recall, bottom button is for memory clear; pressing both buttons allows you to moving the shift point by using the top and bottom buttons as up and down arrows:
The tach and shift light looked so sexy that we couldn't resist trying it out on other things.
Mr. S and I definitely needed to take this picture:
After sobering up, the shift light was test-fit inside the car. I wanted to mount it on the left side of the dash, but unfortunately it wouldn't fit without sitting too high up and entering the visibility zone, which was already hampered by my dual gauge mount. I decided that was unacceptable and, like Mr. S, decided to mount it more centrally in the car. Hey, you've got to reduce polar moment somehow!
This is where test-fitting comes into play. Unlike Mr. S's setup, you can see that the tachometer's visibility is interfered with by moving the steering wheel up and down when it's mounted to the far left. This is not a problem for Mr. S as he's much taller than me and his dash has a different configuration, but it's unacceptable in my case. Plus it interferes with removal of the gauge cluster cover if that becomes necessary.
The shift light itself can be removed from the tach and mounted separately. It comes with a connecting wire about 1' long to mount it wherever you'd like, and a disconnect clip to remove it if you want. I left it on the tach; what's the point of mounting the light stealthily if the tach is on the dash?
Tachometer placed to the far left, steering wheel lowered maximum:
Tachometer placed to the far left, steering wheel raised maximum:
The tach base was moved right until visibility improved in all circumstances.
Tachometer placed more centrally, steering wheel lowered maximum:
Tachometer placed more centrally, steering wheel raised maximum:
Now it comes time to actually begin mounting the tach. The tach is held up by a circular brace or strap that is supported by the pedestal with two bolts. The pedestal itself screws to the dash using two supplied <shudder>flathead</shudder> screws.
Tachometer pedestal:
The tach was left in place on the dash and a bottle of whiteout was used to mark the correct placement on the dash. I don't really recommend this method as you can't get the damn whiteout marker around the tach body and into the little teeny holes. I somehow managed to do it after much cursing. However, it left white marks on the base, which I need to get off there somehow. Orrrr... I could ignore them. Yeah, I'm gonna ignore them
Whiteout marks where the screw holes need to be made:
I used a thinner, sharper screw than the ones provided to begin making a hole in the dash. While it's just regular plastic, due to the location - right under the glass - it's actually quite hard to get those screws in place. Using the starter screw eases the task and makes it less of a chore to thread the supplied screws in. Nevertheless, it took about half an hour to get the screws in place.
Screws being threaded into dash:
After the screws had a thread into the dash, the pedestal base was mounted and tightened firmly.
Pedestal mounted to dash using supplied screws:
Another view of the pedestal mounted to the dash, showing how low it actually sits:
Now it's time to drill a hole in the dash for the gauge wiring. There's a supplied rubber grommet that is designed to cause you the maximum amount of aggravation during install. I used it to size a drill bit large enough to pass 4 12-gauge wires through and mount the grommet, and then began drilling.
Due to the angle of the windshield and the position of the tach mount, the closest I could get to the tach was this location and this angle:
Note that you shouldn't drill too far down, as your heater controls actually reside directly underneath your dash. I drilled very slowly - thanks, Craftsman variable-speed drill!
The completely drilled hole:
After some cleanup, the grommet was installed into the hole, awaiting the tach wires. This is a real PITA to put into place, as the dash plastic is too thick for the grommet's center space to encompass. Thanks to this, I quickly lost the grommet somewhere underneath the dash when the wires were being fed through. Oh well, bye bye grommet.
Grommet installed shortly before going AWOL:
Another view of the installed grommet - too bad it didn't like my car enough to stay awhile, but it looked good while it lasted:
Feeding the wires through was complicated. I taped them all together at the end and used that to go through the grommet at first. It was a tight fit and this is where the grommet decided to make a run for it and vanished into the hole along with the wires, never to be seen again.
The wires themselves tend to get caught on the heater appliances behind the dash. I found it was easier to feed them through one at a time and leave each one hanging under the dash while the next was fed through. Once the grommet was gone there was plenty of room and it was much easier.
Now's where it gets fun. The four wires on the left are the tach wires - green is for tach signal, white is for dash lighting, black is for ground, and red is for +12V switched power. I have all these circuits isolated and labelled already for my other gauges and simply tapped into those. The tach signal was the difficult one.
Tach wires fed through dash, center console piece removed exposing messy wiring everywhere (oh well, it works):
One the 3 simple wires were attached, I had to decide where to get my tach signal from. There's several locations and people espouse each method according to their preference. Some like to get their signal from the blue wire at the gauge cluster feeding the stock tach. Some like to take the feed as close to the ECU as possible, and others prefer to feed the tach signal wire into the engine bay and tap into the distributor directly. I decided to tap off the ECU; who cares what the distributor or stock tach say - it's the ECU that has the final say when the fuel cut comes 'round.
Exposed ECU wiring, B harness unplugged, B15 wire is the tach signal. The green wire at the bottom is the wire for the AutoGauge tach:
A 0.5" section of the wire next to the ECU plug was stripped, the AutoGauge feed wire was stripped, and the the two wires were soldered together and electrical-taped up for protection.
Shot of the completed work:
After this it was a simple matter of putting the tools away, cleaning up, and setting the # of cylinders the tach expects. In order to do this, before you turn the car on, hold down the top 'recall' button. Turn the car on, and the tach will jump from 2k to 3k to 4k spending ~2 seconds at each RPM. 2k = 4 cylinder, 3k = 6 cylinder, 4k = 8 cylinder. I set it to 2k (it was set to 4k previously) by releasing the button when it reached the 2k mark. A second later the tach zeroed and it was ready to go.
A quick check of the systems and I started it up.
Tach functioning correctly:
The shift point came preset at 6500 rpm. I set it low - about 3k - and test-revved it to see how the shift light looked. DANG BRIGHT!
Holy momma that hurts my eyes:
Final thoughts: Basically, once the shift light comes on, you're blind. You can't see anything else until you shift because that light is pointed directly at your eyes.
Getting used to the tach is hard after driving my car for about 6 years with it on the left of the cluster. I caught myself watching the stock tach when taking it to redline, and right now, the shift light more startles me than makes me want to shift. I think once I get used to it it'll be very, very helpful, but right now it's just confusing.
Cool things: I can set the shift point while driving; the $169 tach won't let you do that. I can also check my peak RPM level while driving and reset it on-the-fly. Plus - damn, does the tach look sexy! It has a very nice finish to it, and the buttons don't feel too cheap. The wires are nice and flexible, not some cheap crap, and the rubber bits are flexible and soft - quality stuff.
Not-so-cool things: The ugly yellow dust cover for the shift light. That thing is so bright it screams 'look at me!'. I plan on taping it up or something to make it darker and less noticeable. Also, the tach doesn't always remember the shift point correctly between driving sessions, meaning you should set it each time you drive the car. That's going to become annoying very rapidly, but that's why I paid only a little over $200 after taxes and not $500 or whatever for an AutoMeter monster tach.
05-11-2003, 10:46 AM
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Re: Tech article: Installing a monster tach: how-to (raene)
THe ugly yellow dust cover you are talking about is to cover the shiftlight at night so you dont go blind. There are other colors you can get for the covers and the bulbs.
I used to have a tach in my baja bug. But I would never put one in my crx. My gsr guage cluster works fine
I used to have a tach in my baja bug. But I would never put one in my crx. My gsr guage cluster works fine
05-11-2003, 10:50 AM
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Re: Tech article: Installing a monster tach: how-to (raene)
http://harlan-engineering.com/....html
I use that. It's mounted on the A pillar. I had a 5" tach and shift light mounted on the dash and it got old REALLY quick. Also after a while the weight of the tach wears and the plastic fatigues around the screws and there will be a chunk missing from your dash :-(
I took the 5" tach out, bought an Si guage cluster and set the shiftlight where I want it.
I use that. It's mounted on the A pillar. I had a 5" tach and shift light mounted on the dash and it got old REALLY quick. Also after a while the weight of the tach wears and the plastic fatigues around the screws and there will be a chunk missing from your dash :-(
I took the 5" tach out, bought an Si guage cluster and set the shiftlight where I want it.
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