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The mkiv Supra Owners Club

Boost guages


Barnstormer

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Hi,

 

I have a 1997 J-spec TT and it has a boost guage fitted as standard - part of the facelifted dash I believe.

 

Can anyone tell me if this is a mechanical or electrical guage? I can take the dash off to find out but if someone can save me the bother.........

 

Also the guage has no figures on it just "+", "0", "-"

I assume it is + or - 1 bar.

 

Any info of this guage would be appreciated. I did think about replacing the clock with a 52mm electrical boost guage - any suggestions?

 

ATB

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It's electrical, and more of a boost indicator than a gauge. The maximum on mine corresponds to about 0.5 bar. The only calibrated mark on it is the 0, which is accurate. It's only use is if you were cruising down a motorway or something and wanted to stay off boost to save fuel.

 

I've got a Blitz turbo timer that has a built in digital boost gauge. You couldn't really read it as you are driving (not safely anyway!), but it records the peak boost and has a warning, so I use it for that and use the standard gauge as a rough guide to what's going on.

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Could I use the stock gauge sender wire to drive an aftermarket guage? Save having to install another wire through the bulkhead...only trouble is the calibration. I'd have to compare the spec for the stock guage to that of the new one.

 

Has anyone done this?

 

Also if I fit a new electrical guage where does the new sender mount? Is it difficult to fit?

 

Sorry for the q's but any help appreciated.

 

ATB

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Looked around and reckon the the new Greddy ones are the dogs. Easy to read, electrical sender, 52mm so fit into the clock mount and not too expensive.

 

The SPA ones look good but are digital and not analogue - in my job the perfect gauge is often a combination of the two. Analoge for easy to read trend, big picture info for peripheral vision and digital for absolute readings/diagnostics. So far have not found a good combo gauge but will keep a look out.

 

ATB

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Fitted a boost gauge today. Got a 52mm electronic Greddy for accuracy and put it in the clock dash mount. Got my Dremmel out and carved up the clock, fitted in the boost gauge to it. Removed the wiring plug from the clock and attached it to the gauge wiring so if future to disconnect just use the original loom plug. Wired it up a treat - all worked first time except the hazards and turn indicators didn't work! I think I have forgotten to replace a plug from the upper dash - but as it got dark I had no light to finish the job. Or maybe a blown fuse.

 

Took the motor out for a spin before dark and at full throttle shows around 0.8 bar which I reckon is about right for a stock engine.

 

Wired it up so that the gauge back light is on when I turn on the lights although the dimmer does not adjust the level. I could wire the gauge back light to the light in the ashtray to get dimmer control but couldn't be arsed! Bit too fiddly and the back light is low anyway so max is just about right.

 

As I have a face lifted 1997 j-spec with the original owners manual in Japanese I got my wife, who is Japanese, to translate the fuse box diagrams. I made up a spreadsheet with the detail son.I f you want the spreadsheet its here (about 1mb)

 

http://www.teamsamas.com/supra/jfuse.zip

 

I also just got some new ICE - an Alpine CDA-7893R (MP3) - to fit and some new speakers. Good job I have 2 weeks off work to do all this!!!

 

ATB

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Guest Martin F

Two things :-

 

1. You have defenitely left that plug off the top left hand side of the dash. :D

 

2. The dimmer system on the supra works on the earth side and not the positive supply side of the backlight bulbs. So it's not that easy to get a conventional backlight system to dim along with your dash lights. You need to invert the supply from the dimmer control and then feed this to the backlight wire on your gauge. Arnout has a simple inverter circuit on his website http://www.supras.nl specifically for this function.

 

Enjoy your weeks off!!

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Sort of on the same topic here.

 

Does anyone know if you can replace the gauge cluster from a 93 -95 J-spec into a 96 onwards model? Just thought this would be a good idea seeing as the factory boost gauge is virtually useless and I prefer the three large gauges to the two large and three small ones on the 96 onwards model.

 

Sorry for hi-jacking the thread :D

 

Thanks for any help :thumbs:

 

Steve.

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outatime,

 

got the gauge from Tim at...

http://www.specialvehicle.co.uk/

Find the Japanese vehicle page and they have them listed. I emailed Tim and he did me a good price on a new gauge.

 

It is extremely accurate and sensitive - the slightest change in throttle position is instantly reflected in the gauge reading. Much better than the stock one.

 

Also being an electric gauge means that the wire from the gauge to the transmitter is very thin and easy to thread through the bulkhead - in fact it took me about 1 min to sort it out. Thought it was going to be the hardest bit.

 

The only thing with these types of gauge is fitting them to the dash - I used the clock mount by removing the whole clock from the dash. Then remove the clock internals, used my Dremmel to cut to fit new gauge and then refitted. Takes 20 mins with a Dremmel and small file.

 

The only problem I had was a blown fuse which I replaced and it looks fab. Fits flush with the dash and looks almost a stock fit. The only giveaway is the needle is white and not orange like the others.

 

If required might be able to get some piccys if I can borrow a digital camera. Let me know.

 

ATB

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Originally posted by Barnstormer

Hi,

 

I have a 1997 J-spec TT and it has a boost guage fitted as standard - part of the facelifted dash I believe.

 

Can anyone tell me if this is a mechanical or electrical guage? I can take the dash off to find out but if someone can save me the bother.........

 

Also the guage has no figures on it just "+", "0", "-"

I assume it is + or - 1 bar.

 

Any info of this guage would be appreciated. I did think about replacing the clock with a 52mm electrical boost guage - any suggestions?

 

ATB

 

Barnstormer,

I have the face lift style dash, and yes the factory boost gauge may not be all that, but it seems everyone has missed the point of its use. Its not to give an exact reading of what your boost is, it doesnt even run across both turbos, it is only connected to the first turbo to let you know if you have any boost pressure at all, as the first turbo starts at around 1.5 rpm or around that area. It can be a usefull thing if you have no other gauges like the rest of the earlier models, so at least we can tell we have some boost. I would leave it in as the more gauges you have monitoring your turbos the better. I have just recently had a Apexi Boost gauge fitted aswell, so I have the stock measuring the boost on the first turbo and then the Apexi gauge measuring the boost across both turbos. So if one day my Apexi gauge was reading shite boost but my stock gauge was hitting the +, then I know there would be a problem on my second turbo. It makes sense, plus you have more gauges flickering about while driving, and you can beat that for that starship enterprise feel.:sly:

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ashley,

 

thanks for that. I didn't know where the stock gauge took it reading from. I connected my Greddy gauge to the inlet manifold pressure sensor line so am reading inlet pressure which I suppose is the total boost of the combined induction system.

 

My totally stock car runs about 0.8 bar at peak boost.

 

ATB

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