Vacuum Pump on an Ls7
09-26-2017, 05:01 PM
#1
Vacuum Pump on an Ls7 Lots of great info in this thread if you'd like to refer to it: https://ls1tech.com/forums/generatio...installed.html
As far as the physical installation of one of these goes, how is everyone pulling vacuum towards the bottom of the block? I'm just taking an uneducated guess that a 1/8" or 1/4" NPT drilled & threaded hole in each "bay" of the block, staggered on both sides? This makes the most sense to me in my head, but I don't have experience with vacuum pumps. My valve covers and valley cover both have provisions for a vacuum source, but was curious about the bottom end of the block where it really matters, from what I've found. .
Also, I'm building a dry sump tank to suit my chassis. Do I need any kind of breather or an evacuation line that the vacuum pump should be pulling on it? I haven't been able to source this information.
TIA!
As far as the physical installation of one of these goes, how is everyone pulling vacuum towards the bottom of the block? I'm just taking an uneducated guess that a 1/8" or 1/4" NPT drilled & threaded hole in each "bay" of the block, staggered on both sides? This makes the most sense to me in my head, but I don't have experience with vacuum pumps. My valve covers and valley cover both have provisions for a vacuum source, but was curious about the bottom end of the block where it really matters, from what I've found. .
Also, I'm building a dry sump tank to suit my chassis. Do I need any kind of breather or an evacuation line that the vacuum pump should be pulling on it? I haven't been able to source this information.
TIA!
09-27-2017, 10:45 AM
#2
09-27-2017, 01:40 PM
#3
Thanks.
09-27-2017, 03:06 PM
#4
Staging Lane
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Drawing from the valve cover has always worked best for us. There always seems to be too much oil present in the valley and other spots. Some road race applications can benefit from drawing from multiple locations to help with oil control. This is because road racers, unlike drag racers, do a lot of braking and cornering, making the oil slosh everywhere. Drag cars always work best in the front portion of the valve cover.
Your dry sump tank needs to be vented, and the crankcase needs to be sealed.
Your dry sump tank needs to be vented, and the crankcase needs to be sealed.
09-27-2017, 04:52 PM
#5
Drawing from the valve cover has always worked best for us. There always seems to be too much oil present in the valley and other spots. Some road race applications can benefit from drawing from multiple locations to help with oil control. This is because road racers, unlike drag racers, do a lot of braking and cornering, making the oil slosh everywhere. Drag cars always work best in the front portion of the valve cover.
Your dry sump tank needs to be vented, and the crankcase needs to be sealed.
Your dry sump tank needs to be vented, and the crankcase needs to be sealed.
Now I'm not trying to refute the last point you mentioned, and I appreciate the help of an expert, I just want to understand it better (my inexperience with these systems has no credibility, so my mind is trying to put some pieces together and call it "logic"). Everywhere I've looked, I've found GZ Motorsports has the best vacuum pumps for these engines, so I'm trying my best to be humble and not look like an internet expert when I'm far from it in reality. I'd appreciate some clarification!:
Isn't the most amount of blow by going to stay in the bottom end, causing parasitic loss with the crank rotation and piston stroke coming down? Or would the vacuum on the valve covers be sufficient to sustain a vacuum down low? I want to think that with my ring gaps I would benefit greatly if there was a direct vacuum source pulling down low, but I may be overthinking it! I'd really like to be able to wrap my head around it, and I think I should still get in touch with you, personally, later on when it comes time to add the vacuum pump system and storage tank so you can get me properly set up (externally).
Thanks!
09-27-2017, 10:28 PM
#6
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Your engine has enough air passages between the heads and crank area that any pressure differential will equalize almost instantly. every time a piston goes down, another one is going up, so the only pressure is from blow-by.
You can call or email me any time all the contact info is on our web site.
You can call or email me any time all the contact info is on our web site.
09-28-2017, 06:42 AM
#7
That's a good point about pulling from the front of the VCs in drag applications - probably 25% of my time with be at the drag strip with the other 75% being street, for the most part. I hadn't really considered that. Thanks for the note on venting the oil tank, too. I can easily add that in.
Now I'm not trying to refute the last point you mentioned, and I appreciate the help of an expert, I just want to understand it better (my inexperience with these systems has no credibility, so my mind is trying to put some pieces together and call it "logic"). Everywhere I've looked, I've found GZ Motorsports has the best vacuum pumps for these engines, so I'm trying my best to be humble and not look like an internet expert when I'm far from it in reality. I'd appreciate some clarification!:
Isn't the most amount of blow by going to stay in the bottom end, causing parasitic loss with the crank rotation and piston stroke coming down? Or would the vacuum on the valve covers be sufficient to sustain a vacuum down low? I want to think that with my ring gaps I would benefit greatly if there was a direct vacuum source pulling down low, but I may be overthinking it! I'd really like to be able to wrap my head around it, and I think I should still get in touch with you, personally, later on when it comes time to add the vacuum pump system and storage tank so you can get me properly set up (externally).
Thanks!
Now I'm not trying to refute the last point you mentioned, and I appreciate the help of an expert, I just want to understand it better (my inexperience with these systems has no credibility, so my mind is trying to put some pieces together and call it "logic"). Everywhere I've looked, I've found GZ Motorsports has the best vacuum pumps for these engines, so I'm trying my best to be humble and not look like an internet expert when I'm far from it in reality. I'd appreciate some clarification!:
Isn't the most amount of blow by going to stay in the bottom end, causing parasitic loss with the crank rotation and piston stroke coming down? Or would the vacuum on the valve covers be sufficient to sustain a vacuum down low? I want to think that with my ring gaps I would benefit greatly if there was a direct vacuum source pulling down low, but I may be overthinking it! I'd really like to be able to wrap my head around it, and I think I should still get in touch with you, personally, later on when it comes time to add the vacuum pump system and storage tank so you can get me properly set up (externally).
Thanks!
If you have any questions feel free to ask. I have all the ports on the engine plugged up and the oil tank vented
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10-03-2017, 08:00 AM
#10
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That looks nice (and tight!). I'm wanting to put one on my build but I'm using the Vintage Front Runner system (w/ac) and both heads are covered up pretty good making the GZ bracket worthless. When I get the engine installed (hopefully today) I'm going to look at designing a bracket that will work with my mess...