7mge Cluster in 7mgte

[Emeraldage]

Okay so I have a 89 NA... An engine from a 90 turbo. Someone wants to purchase my turboh gauge cluster. I want to keep my na cluster with the correct mileage. I've heard the tach doesn't work?

I have a buddy who knows all about electronics circuit boards etc. I heard you just have to change resistors right? How difficult is the task and is there a guide?

 

[bad88mk3]

The best way to go about doing this would to be to use just the tachometer from a turbo cluster in your cluster or put your speedometer in the turbo cluster as the speedometer's are identical between the two. But the tachometer from the n/a will not work with the turbo motor/electronics without modification of the electronics/resistor but it does fit right in perfectly just wont function properly. Hope this helps

 

[Emeraldage]

Okay thanks. I know I talked to a friend about it before he said the only thing that won't work is the tach. And that I need to change a resistor in it. Is there a guide somewhere to do this? I know a friend who's capable of doing this kind of electronic work easily.

 

[bad88mk3]

Your welcome and i believe this might be what your looking for. www.supramania.com/forums/showthread.php?125640-NA-Tach-Conversion-to-7M-GTE

 

[bad88mk3]

And here is another link. www.4cefed.com/tech/natachchanges.jpg

 

[Dan_Gyoba]

Gauge cluster otherwise works perfectly. I still have the NA gauge cluster in my '89. Yes, you need to change the tach, but it's not difficult to do.

I don't think that the '90 wiring harness will plug 'n play in the '89. The '87 harness and ECU was *almost* pnp with the '89 chassis, with the exception of the headlight line to the ECU. The ABS needed a bit of adapting as well, but everything plugged in.

 

[Emeraldage]

Changing the tach as in the part or the resistor? I feel like I should wait till we got it all together and working first. Because any RnD projects with the car typically scare me a bit. But I can make 100$ shipped for the cluster right now and that's enough to get my head studs, gaskets, and tubes and it'll have everything to finally finish the swap... After like 6 months of the engine sitting on a rack. And I hope the 90' harness will pnp. I bought a 90 turbo computer for it.

So to confirm to get the gauge cluster to work all it is is swapping those resistors indicated in that picture bad88 linked? And then all gauges will work correctly? (I'm not worried about boost gauge on stock power as the boost sensor was broken anyways).

 

[Dan_Gyoba]

Well, I just took the driver board from the turbo cluster, but you could just change the resistors as well, and have 2 functioning gauge clusters.

 

[Emeraldage]

Suppose if I follow this: http://www.4cefed.com/tech/natachchanges.jpg then all the gauges will work properly? I'm not sure about the battery voltage though since that's normally a boost gauge... All I've heard from a friend is the tach won't work until resistors are changed. Just scared to take a chance on this but instant money for the swap which we definitely need haah. Have to find that resistor board hopefully it's not difficult when I get it apart.

 

[bad88mk3]

Its not to bad to do the resistor swap you just go to radioshack get the correct resistor's you need there very cheap so I would buy a few extra just in case your soldering skills are not the best. just be very careful taking the gauge cluster apart as they can be very brittle after 20+ years and there are some screws that are hard to find to get it apart so make sure you don't forget any of them or you may break it.

 

[Dan_Gyoba]

Resistor swap is easy, provided that you can handle a soldering iron. If not, you just need the driver board from the turbo cluster.

Note, if you take the driver board from an '87 cluster, and connect it to the tach on an '89+ gauge, you may not get the results that you're expecting. It seems that the gauges themselves are a bit different. In the '89 my tach reads a bit under 5,000 RPM when the engine hits the rev limiter, which I believe is at 7,000. As a result, I treat an indicated 4,500 RPM as redline while driving, and gear/speed/RPM calculators seem to bear me out on this being correct. I still have the actual '87 gauge, which I've been meaning to swap back in, just using the '89 face and needle, but I haven't done it yet. (I figure though that I should just be able to make an adjustment somewhere to correct the tach. Maybe using a pot, so that I can trim it to match a diagnostic tach exactly.)

The NA voltage gauge just works. No need to do anything at all. The boost gauge connects differently tot he wiring harness. You can actually swap in the NA voltage gauge to the turbo cluster if you want. I had considered it for the '90 since the factory boost gauge will be redundant, but it really doesn't matter.

 

[Emeraldage]

Okay awesome thanks guys. Yeah I'm not gonna be the one doing the actual resistor soldering and all. I have a friend who does that stuff for a hobby he's fixed stuff on modern electronics for me so I figure old electronics shouldn't be a big deal haha.. It's a 89 NA cluste rin my car. THat will have a 90s turbo harness and comp. The only difference I notice in the clusters the red like on the turbo is like 6200 instead of 6500 hundred or whatever. Makes sense being a na to make more power just assuming the 7mge revs up a lil more. But thanks for the advice now I can make some more money and have plenty to finish the swap. Also that picture that other guy linked as well as I relinked that's the correct resistors I need to change right?