Guest BobFitz Posted August 30, 2014 Share Posted August 30, 2014 (edited) Where do I connect the vacuum/pressure line on a DOHC for a boost gauge?Thanks,Bob Edited August 30, 2014 by BobFitz (see edit history) Link to comment Share on other sites More sharing options...
Digger914 Posted August 31, 2014 Share Posted August 31, 2014 Where do I connect the vacuum/pressure line on a DOHC for a boost gauge?Thanks,BobEasiest place you can find to T tap to the throttle body vac line.Or you can get really crazy and drill, tap and pipe into the turbo itself. Link to comment Share on other sites More sharing options...
Guest BobFitz Posted August 31, 2014 Share Posted August 31, 2014 OK- Thanks. I'll see which is easier to get to. Link to comment Share on other sites More sharing options...
Digger914 Posted August 31, 2014 Share Posted August 31, 2014 (edited) OK- Thanks. I'll see which is easier to get to.Anywhere on the 1/4 in ID rubber line is the easiest to get to, the closer you get to intake Throttle Body the more accurate your measurement and the most accurate...drill and tap into the turbo, not recommended if you have to ask where in the turbo.Almost forgot, if you need electricity for your gauge tap the radio power feed. Edited August 31, 2014 by Digger914 (see edit history) Link to comment Share on other sites More sharing options...
Guest BobFitz Posted August 31, 2014 Share Posted August 31, 2014 I am using a 4 in. test gauge right now. I may get a 2 in. one to install permanently.Is there enough metal to tap(1/8 in.pipe?) where the hose going to the intercooler attaches? Link to comment Share on other sites More sharing options...
Digger914 Posted August 31, 2014 Share Posted August 31, 2014 I am using a 4 in. test gauge right now. I may get a 2 in. one to install permanently.Is there enough metal to tap(1/8 in.pipe?) where the hose going to the intercooler attaches?I have seen the DOHC turbo and from the look of it there should be, but I have never poked a hole in one and can't say yes or no. Link to comment Share on other sites More sharing options...
89TC-16V Posted August 31, 2014 Share Posted August 31, 2014 ive always tapped into the brake boost line for boost gauge installs. as the tc does not have a brake booster, it does not work. you could t-into any of the larger vacuum hoses on the bottom of the intake for a vacuum source, the boost gauge only needs a tiny vacuum line. I know this because on my Daytona install, I used t-d into a vacuum line from there to run my brake booster in the Daytona that had a 16V masi motor in it. Link to comment Share on other sites More sharing options...
Guest BobFitz Posted August 31, 2014 Share Posted August 31, 2014 (edited) " I have never poked a hole in one and can't say yes or no.Hmmm.... Might be risky.I don't see a 1/4 in. hose and can barely see the TB. Poor lighting this AM. Have to get out there with a light later. Edited August 31, 2014 by BobFitz (see edit history) Link to comment Share on other sites More sharing options...
Digger914 Posted September 1, 2014 Share Posted September 1, 2014 " I have never poked a hole in one and can't say yes or no.Hmmm.... Might be risky.I don't see a 1/4 in. hose and can barely see the TB. Poor lighting this AM. Have to get out there with a light later.When working in the dark you can always try the Brail method, find the vac line at the cruse control and follow it back to its source, that should give you a fist full of lines to chose from and eventually you find the one that gets closest to the throttle body. Link to comment Share on other sites More sharing options...
Guest BobFitz Posted September 1, 2014 Share Posted September 1, 2014 I have silicone vacuum hose on order and when it comes in I will T into some of the lines and see what works.Thanks for all the suggestions.Bob Link to comment Share on other sites More sharing options...
Hemi Dude Posted September 3, 2014 Share Posted September 3, 2014 Where do I connect the vacuum/pressure line on a DOHC for a boost gauge?Thanks,Bob Think about it! Both boost and vacuum is present equally in the entire intake manifold once it has passed through the throttle body. The boost pressure felt there is the boost the engine is actually receiving. Do not tap into the turbo as you will not see engine vacuum and the boost pressure will not accurately reflect what the engine is actually receiving. Although I have a boost gauge on an 8 valve engine, the same applies on the 16v engine. Find any 1/8" vacuum line attached to a vacuum source mounted in the intake manifold and Tee into that line for your boost/vacuum gauge.<script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script> Link to comment Share on other sites More sharing options...
Guest BobFitz Posted September 3, 2014 Share Posted September 3, 2014 Thanks Hemi. Would "any 1/8 in. line" include the one going through the firewall for the A/C /heat /defrost selector? A you may know the 16 valve intake hides lots of stuff below it.Bob Link to comment Share on other sites More sharing options...
Hemi Dude Posted September 3, 2014 Share Posted September 3, 2014 Thanks Hemi. Would "any 1/8 in. line" include the one going through the firewall for the A/C /heat /defrost selector? A you may know the 16 valve intake hides lots of stuff below it.Bob This one has a 1 way check valve in it, either in the engine compartment or under the dash, to maintain vacuum even under load. Theoretically, you could connect to it prior to the check valve. Personally, I did not. Test it out and see how it works. It could be your easiest way to connect the gauge.<script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/51f6e16b/background/helpers/prefilterHelper.js"></script> Link to comment Share on other sites More sharing options...
Guest BobFitz Posted September 3, 2014 Share Posted September 3, 2014 This one has a 1 way check valve in it, either in the engine compartment or under the dash, to maintain vacuum even under load. Theoretically, you could connect to it prior to the check valve. Personally, I did not. Test it out and see how it works. It could be your easiest way to connect the gauge.OK-new hose should be here in a few days and I will try it and report back.Thanks again,Bob Link to comment Share on other sites More sharing options...
Guest BobFitz Posted September 7, 2014 Share Posted September 7, 2014 This one has a 1 way check valve in it, either in the engine compartment or under the dash, to maintain vacuum even under load. Theoretically, you could connect to it prior to the check valve. Personally, I did not. Test it out and see how it works. It could be your easiest way to connect the gauge.T installed in 1/8in. line going through firewall, seems to work fine.Anyone know what a good vacuum reading at idle is? How about boost? Link to comment Share on other sites More sharing options...
89TC-16V Posted September 7, 2014 Share Posted September 7, 2014 Good vacuum is between 16-20. Boost maybe 12psi Link to comment Share on other sites More sharing options...
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