Gauge cluster.

[Berg9987]

Well my car is not brutal with its 4A-GZE engine swap. However I have been visiting this site a lot and as such feel like I should contribute something. So this is a little project of mine that might help with some engine swaps. This is pretty much copy and pasted from a thread I made on another forum. I realize that there are some people who won’t like, and that’s fine. I also have a Megasquirt 2 ECU almost ready to go in, and this ties loosely into that project as well. Apologies for the cell phone pictures. Enjoy!

When I bought my MR2 it already had a 4A-GZE swap and some other modifications including a Momo steering wheel. Having driven MR2’s of the same vintage with the stock wheel in place I have found that I prefer the smaller wheel. Unfortunately with where I sit in the car the top of the steering wheel obstructs the view of the top outer two gauges and the indicator and high beam lights. The two gauges it obstructs are the volt meter and the oil pressure gauges. The oil pressure gauge in the dash has never been accurate due to the fact that the person who did the swap left the 4A-GZE sender on the engine and it gives different values than the 4A-GE sender that was matched to the gauge. I solved this problem with an oil filter sandwich plate, a Lotek a pillar mount, and Autometer z-series oil pressure and oil temperature gauges.

I also had a boost gauge in an Autometer mount bolted to the steering column. At first I had an Autometer mechanical boost gauge in there, but it wasn’t the best idea to run a boost/vacuum line from the engine, through the firewall, under the carpet, under the centre consol, through the dash to the column. This line did get pinched so I decided to put an electrical gauge in it’s place. I ended up buying a second hand Greddy gauge. It looked fine during the day but at night it had an orange-red LED illumination that didn’t match the rest of the gauges (stock black face white numbers with green illumination).



In that picture the dash is blue. That dash cracked and it now has a black on in its place.
Recently I started to work on my Megasquirt for the car. This led me to thinking more about the overall car in more detail. The Lotek a-pillar pod is great, but it didn’t quite have the fit that I wanted. I tried to heat it and bend it with a hot air gun, but this just led to the plastic warping. Not wanting to damage it further I put it back on the car (it mounted with two screws) and left it. Last summer I decided that I was unhappy with how it looked and that I would stop worrying about screwing it up and do something about it.

I grabbed a knife and a hacksaw and I cut the gauge pod up such that only the minimal amount of plastic to get it to hold the gauges remained. I then used some two part epoxy to glue it to the stock a-pillar. After it had dried I used some fibreglass reinforced body filler to blend it together. I then used some standard body filler to smooth out most of the imperfections (I say most because there were some that I didn’t notice until after I had put it back on the car).




It was then a case of sand, fill, sand, fill until finally I hit it with some high build primer.



Again it was prime, sand, repeat. Once I had it finished I painted it with some Krylon satin black. It ended up looking gloss black.



I went back to the store and picked up some Krylon flat black. It matched the interior almost perfectly. I was pretty happy with the results. Sorry no pics of that.

One of the issues I had with my megasquirt install is that the output from the MS will not drive the tachometer directly. I have the unit set up on the bench to run distributorless ignition using two coils from a nineties era GM. I solved that problem by using a relay coil connected to the tach output of the MS. However for simplicity’s sake, it would be easier to use an aftermarket tach, but I didn’t want a huge tach glaring at me awkwardly bolted to the dash somewhere.

The synchros on the transmission are worn out and I found that it is cheaper and easier to convert a later model transmission from a front wheel drive car than it would be to get an MR2 transmission or rebuild mine. Since there are many 20V 4A-GE swaps happening in RWD corollas there are several 20V transmissions not being used taking up space in garages. I was able to pick one of these up cheap.

It’s off of a silvertop so the only modification I need to make is to drill a hole for the selector shaft.

Another big issue that my car has is that it simply EATS speedometer cables. Since I bought the car it has chewed up the cable it came with, two junkyard cables, and two brand new ones. Since the new ones are $300+ with no warranty and full payment before ordering, this was getting expensive.

The new transmission I got didn’t have a speedometer cable drive, but rather a vehicle speed sensor (VSS). I have a second engine for the car that came with a supercharged transmission with a VSS, but it was different (installed through the back instead of the top). However the plug was the same.



So this got me thinking, why should I keep sinking money into parts that are going to break when I have everything to convert to an electronic speedometer? Combine this with the fact that an aftermarket tachometer would be easier to drive and the stock volt meter, coolant temperature, and oil pressure gauges were pretty much useless with their simple H and L markings and the top two weren’t even visible unless I moved my head and I found the motivation to make my own dash.

Here are the “before” pictures:



I started with a little bit of research. I wanted everything to look consistent, ie. be the same brand/style of gauge, and I wanted them to be useful. That means accuracy and actual numbers on the gauges (no more of this H and L nonsense).

I researched several companies that make gauges but in the end, for the price and availability in my area I settled on Autometer. Autometer has many different styles of gauges with different faces and fonts and illuminations. I started by picking a speedometer. I would need electric and programmable. Living in Canada I would also need metric (Kph). I also wanted one that would fit in the dash (not 5”) so I settled on the 3 3/8”. This narrowed my selection to four gauges: Sport-Comp, Ultra-Lite, Carbon Fiber, and Phantom. The Phantom series has a white face and black ring. I didn’t think this suited the car. The Carbon Fiber has a chrome ring which I’m really not a fan of. It came down to the Sport Comp with its black face and silver ring and the Ultra Lite with the silver face and silver ring. I checked out the other gauges that I would be using in both these series. According to the Autometer website the Pro Comp does not have full sweep electric gauges for most of the gauges I want. So I went with the Ultra Lite series.

The next decision I had to make was to determine what I wanted to monitor. I decided that I would have oil pressure and EGT in the a-pillar. On the dash I would have RPM, speed, fuel level, and Voltage. Over the centre console above the heater controls I would mount three more: Water temperature, Oil temperature, and a wideband air/fuel ratio for tuning the megasquirt. Finally I would put the boost gauge on the steering column.

I ordered five gauges right away: Tach, Speed, Boost, Volt, and Fuel level. Once they arrived I used my spare gauge cluster as a template and cut up many cardboard boxes for trial fittings (the paper/cardboard recycling bin is right outside my lab). I went through a couple of designs before I settled on having the two larger gauges in the middle with the smaller ones outside of these two at the bottom. I found that I could mount two more small ones above the two that I put in, but the steering wheel would make these hard to see.

I wanted it to fit like a stock gauge cluster so I started by taking apart my spare cluster and using that as a mount:

I dremelled this out such that only the frame remained:


And a cardboard test fit:



This cardboard test fit is pretty much my final design with LED holders for left and right indicators, high beam indicator, a low fuel warning indicator (car has senders in tank for a fuel gauge and a low fuel warning light stock). If you have a keen eye you may have noticed a knob in the upper left where the stock volt meter was. This is for dimming the lights on the new gauges as I will be using LEDs which can’t be dimmed with the stock rheostat. Instead this controls a pulse width modulator for LED dimming.

After I was satisfied with the fit It was time to move onto building a more solid piece. I took my cardboard template and used it to cut a piece of hardboard to the right size:

I then cut holes in it for the gauges using a drill, jigsaw, and dremel and did another test fit:


The PWM is mounted using countersunk bolts that will be filled in.
Once all the holes are cut I removed the gauges and put it in place:


To keep it in place two part epoxy was used:


Once that was done I used some fibreglass to reinforce the edges and some fibreglass filler to smooth out the corners (sorry no pics). Then I hit it with some high build primer and found that I still had a lot of work ahead of me:


Making the thing one colour makes it easier to see the scratches and pin holes that need to be filled. Anyone who had done fibreglass or body work knows that a seemingly endless cycle of filing and sanding and priming and starting over is the next step. Of course I couldn’t resist test fitting in between these stages:





I also had to make sure that it fit in the car:


And that there was enough space behind them for the wires:


Finally I was satisfied enough to paint it its final colour. The same black I used for the a-pillar:



Now that that was done I turned my attention to the boost gauge. Originally I had it in an Autometer mounting cup on the steering column. This worked but as you can see from my before picture way up near the beginning of this thread it stood rather high and blocked much of the speedometer. I decided that I would mount it as low as I could on the steering column. I started by heading to the hardware store with my boost gauge and finding a pipe that would fit it. The closest I found was a vacuflow coupling. I then sat in the car with the column cover and the coupler and cut a notch for the coupler to sit in and deep as I could before it hit the parts of the column underneath.

Once that was done I used epoxy to glue it to the column piece:


This wasn’t deep enough to hold the gauge and cover the wiring behind it so I cut a second connector in half using my dremel. Wear safety glasses and a mask when doing this:

It too was glued in place:

I had to dremel the inside of the couplers a little because they were a little too tight for the boost gauge:


I then used some CA glue to glue some old t-shirt material over the connectors:

And the applied some fibreglass resin mixed with harder:


I should note that this should be done wearing a mask and preferably outdoors. As winter in Canada makes it almost impossible to fibreglass outdoors I used a fume hood in my lab at work (after hours and at lunch of course).

The part now has its shape, but it has no strength. So I cut up some fibreglass chop matt and applied that with resin:



In the last picture you can see that I also covered the hole for the cruise control lever that I no longer have.

I then test fit it against the gauge cluster I built. This is a worst case scenario as the column will never actually be this close to the gauges:


Looks good to me!

[Berg9987]

A little fibreglass reinforced body filler:



A little sanding:




Lather rinse repeat (many times).

A little high build primer:




And finally a test fit in the car:




Test fit with the new gauge cluster:



And again with the flat black paint:




Now there are a few little imperfections in it that bother me a bit, but I’m happy enough with it to put it in the car for now. I don’t want this one little part to wear me down too much.

So now it’s time to start looking at the wiring. I needed to test whether all the LEDs would work with twelve to fourteen volts (to make sure my resistor values were correct). So I used my bench power supply which I can vary the voltage with and tested.
Turning indicators:

Hi beams:

Low fuel:


The only LEDs I had at the time were the “super bright” ones, so I upped the resistance a bit to cut the brightness down some. I don’t want to be blinded by my dash at night.

I also tested that all the gauges powered up:

Many of the Ultra Lite gauges have peak memory and warnings built in. Where I can I would like to use them. The Voltmeter has one and I set it to warn at twelve volts or lower:


The reason for twelve or lower is that I no longer have a charge warning light. When the vehicle is running the voltage should be between thirteen and fourteen volts. If the vehicle is running and it’s at twelve or lower the alternator isn’t charging. So now I have a pseudo charge warning light. The boost meter has this function too, which could be used as an overboost warning. With my supercharger though I fully admit that it’s just for show.

I also tested the night time illumination. In my lab there are some lights I can’t turn off so I can only simulate low light conditions:


I am a little concerned that the two larger gauges might not have enough light for night time driving.

Once it was all confirmed to be working I made a wiring harness for it. It uses one twelve pin Molex plug to make it easy to install/remove. I also made the harness long enough that I can pull the gauge cluster out far enough to get in behind it really easily:


Yesterday was family day here in Canada so I went over to my parents and borrowed their heated garage. I used the wiring diagram for my car to wire up the mating Molex plug for my dash. After a few hours it was in and (for the most part) working.

Here is how it looked this morning right after I started my car:


All in all I am very pleased with the gauge placements. I can see all the gauges easily when driving and the turning indicator lights are finally visible. The fuel gauge seems a little funny. I am using a fully programmable on which requires that I calibrated it when the tank is empty, then fill the tank and calibrate it again. I had cut the fuel sender wire and brought it out under the dash for this purpose. I used power from the cigarette lighter to power the gauge and then calibrated it last time I filled up.

This morning on the way to work It would move from ¼ tank to ½ tank depending on what the car was doing. The stock gauge had just over ¼ tank on it when I removed it so for now I have to keep in mind that the lower reading is probably more accurate. I do not know what it will read when it gets down to the empty value I calibrated it for. I will have to wait and see. I also noticed that the boost gauge calibrates itself each time it gets turned on. I don’t yet know if I have to let it go through its calibration before I start the car (what I’ve done so far, I like watching all the gauges calibrate themselves) or if I can start the car right away and it will remember the initial value. I’m sure I’ll find out through trial and error at some point. The tachometer seems to be much more reactive than the stock and I also suspect more accurate. I do have a few issues to sort though:

Problem: Speedometre doesn’t work.
Reason: VSS not installed.
Solution: Find a way to remove stuck cable drive and install VSS. Last time my father and I tried to get it out we broke the threads for the cable off. I’m not sure how to get it out. Alternatively just wait until I swap the transmission.

Problem: Gas warning light is on all the time.
Reason: Sender for warning light is not a simple on/off as I assumed. When it is in its off state it has a resistance of 2.5Kohm (at least it does when there is ¼ tank). This results in a small current that isn’t enough to turn on the original bulb, but is enough to turn on an LED.
Solution: A slightly more complex circuit. By placing six volt zener diode in series with the LED and a resistor in parallel with the zener/LED circuit then connecting that to the switch in the tank will give me the control I need to turn this on only when the sender drops its resistance. Here is a diagram of that circuit:



It works by having the zener require six volts to allow current to flow through it. At the top of the circuit there is twelve volts. However the zener/LED part of the circuit isn’t referenced to ground, it is referenced to the top of the fuel warning sender below the resistor in parallel. The voltage seen at the bottom of this resistor needs to be greater than eight volts when the sender isn’t turning on the light. Eight volts comes from fourteen volts when the car is running and charging, minus the zener voltage of six. When the sender goes to ground to turn on the light the voltage after the resistor will drop significantly, and if the sender goes to ground like I first assumed, then this point will also be ground. This will make the zener “see” twelve volts, which is higher than six, so the LED will turn on. I will bring the wire for this out under the dash (probably tomorrow night) and connect it to a stock light bulb. When the light comes on I will measure the resistance for the sender and use that to calculate a value for my resistor.

Problem: High beam indicator isn’t working.
Reason: Both high beam filaments burnt out.
Solution: Replace bulbs.

Problem: No idiot lights.
Reason: Did not build them into new dash.
Solution: I plan to move the useful ones to the centre of the dash above the heater controls. By useful I mean Charge, Low Brake Fluid, Hand Brake, and Cooling Fan Fault. Originally the low brake fluid and hand brake shared a light, but I would like to separate them. The two lights I will not be reconnecting are the Check Engine Light (Megasquirts doesn't use it) and Fasten Seat Belt Light. I feel naked in a moving car without a belt so its not like I'll forget.

Problem: All the new gauges are using Autometer’s blue LEDs for lighting. The smaller gauges look great however the larger two cannot be seen in no light conditions. They can be seen when driving under a street light and in low light conditions, but at eight thirty last night I couldn’t see them on the dark streets.
Reason: The Autometer LED’s just aren’t bright enough for the larger gauges.
Solution: Different LEDs. I purchased a couple of blue dash LEDs online. I tested one of the blue dash LEDs and it is bright enough to warrant not looking directly into it. I will do a comparison with the Autometer LED in one of the gauges and the new LED in the other.


Problem: One gauge is lost. The stock cluster had six gauges in it, RPM, speed, voltage, oil pressure, fuel level, and coolant temperature. My gauge cluster has RPM, speed, voltage, fuel level, and I have oil pressure and oil temperature on the a-pillar.
Reason: I built the cluster to have all the gauges easily visible. This meant that I did not have space for any more gauges.
Solution: Mount a water temperature gauge elsewhere. My current vision is to have oil pressure and EGT in the a-pillar and water temp, oil temp, and A/F above the heater controls. This should give me all the gauges I desire.

The start up self calibration dance (click the pic):


I have picked up some non-super bright green and red LEDs to replace the ones in the dash. Unfortunately my local electronics store does not carry non-super bright blue LEDs (nor can I find them anywhere). There just isn’t a demand for them. The guy working the counter even told me that I was the first person to ever ask for non bright ones.

I also picked up my oil pressure gauge today. I was thinking that I could just swap it out for the Z-series gauge that is currently in the a-pillar and use the same sensor. I was wrong. The new gauge has a three wire sensor instead of a one wire sensor like the Z-series. This means that the gauge isn’t relying on the sensors grounding through the engine/frame. Instead the gauge outputs a ground and a voltage to the sensor and the third wire inputs a voltage back to the gauge. Usually this makes for a more accurate reading (and it's more expensive, that makes it more accurate right... right?).




The new oil pressure gauge is in. I have it set such that anytime the oil pressure drops below 30psi the warning light comes on. I changed out the sensor when I did an oil change last night and all the wiring was fairly simple. As with the boost gauge sensor I had to extend the harness a few feet.



As you can see I also changed out the oil temperature gauge for an EGT gauge. I’ve had this gauge since I put the new exhaust on but never got around to mounting it. I put this one in so I can get used to it being there before changing it for an Ultra Lite series gauge. Also the water injection LEDs are not mounted yet. Because I'm using a new mounting system I have to get new LEDs.

This left me with no way to monitor the temperature of the engine, so I re-routed the sensor wire for the oil temperature gauge to the centre consol and put the gauge there. This gauge currently isn’t mounted and does fall over going around corners, but I just wanted it to be there for me to look at occasionally until I get the chance to build my centre consol gauge cluster.


I was also poking around with the megasquirt tuning software and found that it has a preset built in for an Autometer 0-4V wideband A/F gauge. So now I am thinking about using that to feed a wide band A/F signal to the MS instead of the LC-1. I don’t know which would be cheaper, but it would be nice to have all the gauges match. The Autometer gauge I'm considering is part number 4378.



Cheers,
Berg

[coanda]

This is some great work - I think the gauge cluster(s) look great, and the finish seems to be really high. I would have decided against the a-Pillar dials, and would have put those gauges above the centre console, but the work you've put into it is first class.

[Jiff Lemon]

Awesome post! Thoroughly enjoyable read.
Got a few dash mods planned myself, but keeping them close to the chest for now!

[Berg9987]

This is some great work - I think the gauge cluster(s) look great, and the finish seems to be really high. I would have decided against the a-Pillar dials, and would have put those gauges above the centre console, but the work you've put into it is first class.

I'm in the process of building a housing for gauges above the centre console. The current plan is to have three gauges in that piece along with various indicator light (hand brake, low brake fluid warning, fan fault, etc.). I'll be running Oil pressure and A/F ratio (for the megasquirt) in the a-pillar with Oil, Water, and Exhaust temperature in the centre. Unfortunately work has been sending me on trips to the other side of the work (New Zealand) so I haven't had much time to make progress on it.

Thanks for the feedback guys!

I'd like to see what yours looks like when you're done Jiff!

Cheers,
Berg

[Paul Woods]

There's a very high level of work going on there, fantastic stuff, it looks really good too, a strong contender for thread of the month methinks!

[nik]

i agree paul..
this is a nice tidy finish but ultimately time consuming so hats off to you for putting the effort in, it looks great..

[adamh]

wow, awesome post, and the work looks excellent in its finished state

[hmmmmm]

Im just repeating what everyone has been saying but this looks pretty damn good! I like that you used after market gauges but kept they dash clean. People that aren't familiar with the car will thinks its oem!

I realize that there are some people who won’t like, and that’s fine.

Those people are idiots :)

[Berg9987]

You guys are too kind!

I'm feeling really motivated to get the centre part done now. Unfortunately I'm off to NZ on Friday for work (not really unfortunately, NZ if fantastic!), but it means I won't be able to work on it again until June. I will be updating this when I start that.

Cheers,
Berg