TimZ Posted August 29, 2002 Share Posted August 29, 2002 I'm pretty sure that this will not not work on a 6 or more cylinder engine. The reason being that since there is a firing event every 120 degrees of crank rotation, it would be very difficult to find a spot where you were not in the valve overlap period of one of the cylinders. Maybe you could get this to work, but you'd need a cam with very small valve overlap, and you'd have to hunt around for a while to find the right spot. This is possible on a 4 cylinder, since the firing events are 180 degrees apart, and it's easier to find a spot where you are not in overlap. It might even work out that the engine's compression would force it to stop in a position that was not in overlap by default - but I'd have to think about this... Quote Link to comment Share on other sites More sharing options...
Guest sabum Posted August 30, 2002 Share Posted August 30, 2002 You guys are just to damn smart for me I am blown away by the knowledge here. Im going racing tomorrow! Quote Link to comment Share on other sites More sharing options...
awd92gsx Posted August 30, 2002 Share Posted August 30, 2002 Even if you just cap off the end of the I/C piping it's still a worthwhile test. If there are leaks in the piping or boots somewhere it's still nice to find and repair them. As long as you can pressure the intake enough to push air out the leaks it doesn't really matter if there are valves open or not if you have an air compressor that will flow enough to fill the intake. I've never bothered to put an engine on TDC while performing the test. However, a good time to perform the test is if you have the camshaft out for any reason (like when upgrading it or something) that would leave the valves in the completely closed position. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 30, 2002 Share Posted August 30, 2002 Originally posted by awd92gsx:Even if you just cap off the end of the I/C piping it's still a worthwhile test. If there are leaks in the piping or boots somewhere it's still nice to find and repair them. I agree - I was going to suggest that, but was in a hurry when I wrote the last response As long as you can pressure the intake enough to push air out the leaks it doesn't really matter if there are valves open or not if you have an air compressor that will flow enough to fill the intake. You will have a very difficult time finding a compressor that will flow enough to pressurize the intake manifold while the valves are open. I've never bothered to put an engine on TDC while performing the test. Okay I had a bit more time, and looked up some typical numbers. Here's the deal - even the stock cam has 108 degrees of overlap, so there are only three 12 degree wide slivers of crank rotation where none of the valves are in overlap. The mild turbo cam that I use has 124 degrees of overlap, so in my case there is no position that I can put the crank in to stay out of overlap. However, a good time to perform the test is if you have the camshaft out for any reason (like when upgrading it or something) that would leave the valves in the completely closed position. Agreed. Quote Link to comment Share on other sites More sharing options...
awd92gsx Posted August 30, 2002 Share Posted August 30, 2002 I suppose with a 6 there would be more valves open at the same time, but, in the turbocharged DSM world spending $5 down at home depot has saved many hours of headache tracking down boost related problems, and it never hurts to try When I get my turbo engine installed in my Z (finally have enough saved up to get new pistons!) I'll try it and see how it goes. Quote Link to comment Share on other sites More sharing options...
Guest sabum Posted August 31, 2002 Share Posted August 31, 2002 Got back late this morning. I actually made it to the finals for my first time. I ran 12.7's-12.9's at 106-108 mph. so I am getting closer. I can probably tweek the rest out playing with the boost. I was just so glad to see 12's again, I did not touch it. I was running high 14's for the I was pissed when the damn car ran flawless all night and fell on its face (in the finals)! I do want to get the equipement to test the intake like you guys mentioned. I will but a bike pump. Can you tell me what sizes I need for a stock t3. Quote Link to comment Share on other sites More sharing options...
awd92gsx Posted August 31, 2002 Share Posted August 31, 2002 Probably a 2" to 2" coupler should work. Just Make sure you cap off the I/C piping at the throttle body. 12.7 is pretty fast! I think the results speak for themselves. Quote Link to comment Share on other sites More sharing options...
Guest sabum Posted August 31, 2002 Share Posted August 31, 2002 sorry I cut out the one line. Was supposed to say running 14's for the past couple weeks. What type air connector do I need? Is this something I can get at a home depot? Quote Link to comment Share on other sites More sharing options...
awd92gsx Posted August 31, 2002 Share Posted August 31, 2002 Hey, I just found this... This could be very helpful... http://www.vfaq.com/mods/ICtester.html Quote Link to comment Share on other sites More sharing options...
Guest sabum Posted September 1, 2002 Share Posted September 1, 2002 thats awesome. I just printed the directions. Thanks! Quote Link to comment Share on other sites More sharing options...
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