Hope this is the right place. I did some searching on here but came u short, I want to add an aftermarket "back up" temperature gauge but keep my factory temp gauge. I am sure someone has done it this way but all threads I could find were replacing the factory sender with the new one. For those that have done it, where have you added the extra sending unit for the new gauge since both cylinder heads are utilized already?

 

Water necks are generally inexpensive and a good alternative.

 

Are there any that will fit with the TPI throttle body? And won't that only help once the thermostat opens

 

If your car does NOT have dual fans then install the sensor in the pass side head; where the fan switch would normally be located IF you had duel fans. This would place the sensor into the head where the coolant temps can be most accurately achieved.

If you place the sensor in the water neck or intake than I'm almost certain that you will get false readings ( too low )

 

Yea that's the problem is with the dual fans using the passenger side head I didn't know if there was a good way to add another sender

 

Being that it is a "backup", you have the opportunity to compare it to your existing gauge to evaluate temp drops. Unless the purpose of this is not so much a backup, but rather that you think that your existing gauge is wrong\faulty.

 

So if I understand you correctly you're saying the water neck would be a way to evaluate the temperature changes not necessarily the absolute temperature?

 

With Gen1 SBC (not sure about later models unfortunately) the water exits the engine at the water neck after passing through the thermostat, flows into the radiator, is cooled, and then returns to the water pump to be pumped through the engine. Being that the water neck is the end of the line, it should be up to full temp. However, I wouldn't be surprised if it were to drop a couple degrees at the filler neck. I would be surprised, though, if it was a significant drop. The down side to this, is that you won't have an accurate reading until the thermostat is open, since there's not much (if any, depending on the thermostat used) coolant flowing until the thermostat opens.

If you're planning on using the secondary temp gauge as a replacement, then I wouldn't use the filler neck. If you're using it just to be on the safe side, it should work just fine.

 

Are there any water necks that are made with a sender bung that will work with my tpi?

I'm thinking to add the gauge I could put the new sender in the driver's side cylinder head to get the most accurate reading and put the factory gauge sender in a water neck for a backup

 

I don't have a TPI car to compare with, but this one might work. I'd compare the shape to the one you have now prior to purchase.

http://www.summitracing.com/parts/fs...model/firebird

 

The sender for the secondary fan screws into a hole in the passenger head. That hole, on the drivers side head, just has a pipe plug in it. Seems to me, that would work fairly well for a temp sensor.....

 

That hole Is already used for the factory temp sender

 

Ooops. Quite correct.

 

No Problem I appreciate any help...Cant believe no one who has done it on a TPI car has chimed in yet...

 

on the drivers side of the block fwd. of the oil filter and press. sensor you will find a plug in the side of block . that's where I put them before on other projects . pull out the plug and insert sensor . more often than not you find a layer of rust scale when you remove plug . just poke it with probe of some type , insert temp sensor . good luck .....

 

If the gauge is compatible with a GM sending unit, just tap the stock wiring. Both gauges can use the same sender.

Pipe thread taps range from $5-30 at most auto part stores. Just drill/tap your housing where ever you want for the sender. Just be wary of it hitting the t-stat.

If you want 'warm up accuracy', drill an 1/8" hole in the brim of the t-stat. It allows minor coolant flow (warmth) to get past t-stat and eliminates the air pocket/stupid "burping" ritual of t-stat removal/replacement. imo

GM thought the t-stat housing/passage fine for the ECM coolant sensor. Seemingly, a more vital item than the gauge sender.

 

Ive got my 2nd sender in the passenger side of the block running to a digital gauge under the dash i rewired my fans to a switch so if i get stuck in traffic i can flick them on when the temp gets to 200.

 

I may go this route too...after some digging in the car it seems that the fans were previously wired to run anytime the key is on. I am thinking of fixing the ecm controlled fan back to normal and then wiring the second fan to a manual switch, but with a 40 amp relay and appropriate components (so the car doesnt become rubble)

Doing this I could use the pass. side cylinder head port for a second gauge.