DatsunBoy77 Posted March 6, 2003 Share Posted March 6, 2003 Where is the best spot to hook up a boost and vaccum gauge on a L28ET engine. What are the best lines to tap into. Is it the vaccum line comming off the fourth intake runner (from the firewall)? That seems to have the most vaccum. Anyone? Thanks . Ryan Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted March 6, 2003 Author Share Posted March 6, 2003 Also, I hooked it up to that vaccum line and it shows 10in. Hg for vaccum. Is this right for idle? I cant say much else because it is about 9pm and i did this fron the engine bay so i couldnt see it while i was driving to as when full boost is on as to what it is reading. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted March 6, 2003 Share Posted March 6, 2003 10 in of vacuum sounds a little low to me unless you are running an aftermarket cam. With the stock cam I had 21" Hg (probably a little higher than most) and with my current lopey cam , I have ~15" Hg at idle. Vacuum should be read from anywhere on the main plenum I believe. It should be pretty consistant throughout the plenum as well. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 6, 2003 Share Posted March 6, 2003 I have -18psi at idle on 8:1 compression stock turbo motor. Did you let the car warm up? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted March 6, 2003 Share Posted March 6, 2003 I have -18psi at idle on 8:1 compression stock turbo motor. Did you let the car warm up? I think you mean inches of Hg, Yo 10" is low, but that's what my engine ran with an aftermarket turbo cam (the Schneider 270/280). Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 6, 2003 Share Posted March 6, 2003 I have -18psi at idle on 8:1 compression stock turbo motor. Did you let the car warm up? I think you mean inches of Hg' date=' Yo 10" is low, but that's what my engine ran with an aftermarket turbo cam (the Schneider 270/280).[/quote'] I guess I just reading what my Autometer boost gauge say. Quote Link to comment Share on other sites More sharing options...
fl327 Posted March 6, 2003 Share Posted March 6, 2003 im seeing 22hg at idle. Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted March 6, 2003 Author Share Posted March 6, 2003 The car was ice cold and the timing is very retarted . It sounds like it has a cam though. . Well, i guess i am gonna go try and pull the dash so i can through in the gauge. Is there a quick way to get to the gauges withought pulling off the whole dash? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted March 6, 2003 Share Posted March 6, 2003 I have -18psi at idle on 8:1 compression stock turbo motor. Did you let the car warm up? I think you mean inches of Hg' date=' Yo 10" is low, but that's what my engine ran with an aftermarket turbo cam (the Schneider 270/280).[/quote'] I guess I just reading what my Autometer boost gauge say. I have an Autometer gauge too. If you look closely, the numbers below 0 are designated as inHg, and the numbers above are designated as psi. Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted March 6, 2003 Author Share Posted March 6, 2003 I think we all have the same Autometer Autogauge gauge. Quote Link to comment Share on other sites More sharing options...
Mudge Posted March 6, 2003 Share Posted March 6, 2003 Since you say your timing is off, that will definately effect idle vacuum. Get it set and check again Quote Link to comment Share on other sites More sharing options...
Tony240ZT Posted March 7, 2003 Share Posted March 7, 2003 Also a very warn engine will show less vacuum. My engine used to suck at 20Hg, and now it's only like 12Hg with a less than stable idle at around 700rpm or so. I've got new rings in hand. Hopefully the pistons aren't bad now Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted March 7, 2003 Author Share Posted March 7, 2003 Got it all hooked up and looking good. At idle it is pulling about 21 in. Hg. Unfortunatly it is now idling at 1000 rps where before it was at about 800rpms. Fist gear is not showing any positive vaccum but in second it is boosting to about 8psi and same through the rest of the gears. Quote Link to comment Share on other sites More sharing options...
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