How to make an old style hood mounted tach work with a 2011 LS3? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

OHIOSS · 05-22-2018, 03:00 AM

I have a neighbor that is restoring a 1967-1969 (not sure which year) Camaro RS & is putting an LS3 engine in the car. He got the LS3 from a wrecked 2011 Camaro SS & he is buying one of the old looking hood mounted tachs. The tach is a remake of the original ones that came on the 1970 GTO & other GM cars.

I am helping him figure this out because he doesn't do computers or Internet. I have talked to 4 different companies that make the old style looking tachs but all of them said they will not work with a new style engine like the LS3. I tried talking to Summit and they don't have any idea how to make it work. I talked to JEG's & they suggested a signal converter but they don't know for sure if it will work or not. Since the tach is electrical it can't be returned if it doesn't work.

I have tried posting on a different Camaro forum & also on a GM forum & nobody can offer a solution. I cannot believe that this cannot be done but so far that is all I have heard. Trying here on C5 is my last hope & if I can't find a solution on here I am just going to tell him it can't be done.

Any suggestions?

orange devil · 05-22-2018, 07:10 AM

Try reaching out to painless performance.. and also Gen 5 DIY?

granatl · 05-23-2018, 09:16 AM

From what I'm reading, his repro tach (with modern electronics) should work. However, it does require adding a wire & pin to the ECU harness, plus re-flashing the ECU to enable that tach output.

https://www.thehulltruth.com/docksid...ng-help-2.html

05-22-2018, 03:00 AM	#1
OHIOSS Russ Drives: Yukon Denali, Charger, CamaroSS Join Date: Jun 2009 Location: Ohio Posts: 2,811	How to make an old style hood mounted tach work with a 2011 LS3? I have a neighbor that is restoring a 1967-1969 (not sure which year) Camaro RS & is putting an LS3 engine in the car. He got the LS3 from a wrecked 2011 Camaro SS & he is buying one of the old looking hood mounted tachs. The tach is a remake of the original ones that came on the 1970 GTO & other GM cars. I am helping him figure this out because he doesn't do computers or Internet. I have talked to 4 different companies that make the old style looking tachs but all of them said they will not work with a new style engine like the LS3. I tried talking to Summit and they don't have any idea how to make it work. I talked to JEG's & they suggested a signal converter but they don't know for sure if it will work or not. Since the tach is electrical it can't be returned if it doesn't work. I have tried posting on a different Camaro forum & also on a GM forum & nobody can offer a solution. I cannot believe that this cannot be done but so far that is all I have heard. Trying here on C5 is my last hope & if I can't find a solution on here I am just going to tell him it can't be done. Any suggestions?

05-23-2018, 09:16 AM	#3
granatl Drives: 2SS RS ABM A6 Join Date: Jun 2010 Location: Pahrump, NV Posts: 273	From what I'm reading, his repro tach (with modern electronics) should work. However, it does require adding a wire & pin to the ECU harness, plus re-flashing the ECU to enable that tach output. https://www.thehulltruth.com/docksid...ng-help-2.html __________________ Jack Bilger

05-22-2018, 07:10 AM	#2
orange devil Account Suspended Drives: 2019 SS 2019 mustang GT Join Date: Apr 2017 Location: California Posts: 1,694	Try reaching out to painless performance.. and also Gen 5 DIY?