I just completed a vac pump (vp103 gzms) mod and took it (97ss - 383 - D1 - M6) out for a test voyage. It had alot more, and, power came on early and was unexpected. Guess it must be working. I dialed it in @ 1/3 atmosphere vac. Running JE -28cc pistons. I'm confused over how the ring seal works and the differenential pressure path over the ring pack. B.

 

The oil stays much cleaner (due to better ring seal and less blow-by???). The 2-baffel breather can is not a good selection for a recirc oil system (pump vane oiling fro street/ road use). I've decided to design my own catch can based on a centrifugal principal which should separate the oil mist droplets better.

Performance is like a whole new engine. Much more torque down low, and, faster engine rev acceleration. I did blowout the Random Tech cats (the bricks are loose inside the can). Sound like loose bolts in a can. Happy to offer information. Thanx CamaroZ28.com. B.

 

Anyone??? OK... Well, I designed a whole new oil/ air separator for the vac pump. A centrifugal design. Better @ removal of oil from the vac/air stream. And, a windage tray to catch and recover the oil to recirc to the vac pump for vane oiling for street use. With FI, I was always disappointed @ the performance untill I did this mod. Best mod I have done relative to performance. Loose everywhere on the street. Tons of fun. I hope that some of you consider this mod on your blown LT1. Thanx Camaroz28. B. (97ss 383 - D1)

 

Also... Since I do not know the rate of wear on the Vac_pump vanes (GZMS uses carbon fiber), I installed a simple 1/8 npt plug_port in the suction line. I can introduce a small amount of oil into the system to lube pump vanes. This is recirculated from the air receiver to the vac pump suction line. Something GZMS indicates is required for street applications. The vac system still shows good crankcase vac. The front bumper centrifugal vac air reciever handles oil better, and, allows better motor compartment space control. B. Thanx camaroz28.

 

why not use the inlet side of the D1 to pull vacuum?

 

There is alot of blowby with the typical centrifugal blower system. Vac pump seals the rings much better since it is pulling a vac (negative pressure) all the time under the piston (About 6 to 8" Hg @ 1200 rpm). Also, with a long 6" rod, the rotating assembly tends to increase the crankcase pressure with rpm. And, what the heck, not many have done this mod with 4th gen blown F_bod. So far, I am very pleased with the added performance. I did not get the information I wanted when I started this mod, but, I am willing to learn and venture on my own. Just offering information which is what camaroz28 is all about. B.

 

Hey I'd like one if you're offering one for sale. Actually I'm going to do the crankcase evac kit. Should be just as good I'd think.

 

Well, I only made a prototype vac air receiver, but, it would work with an evac kit. I mounted it inside the front bumper (near the Vac pump). With an evac system, the suction line would be a long distance. The vac receiver is only 6" long 3 1/2" dia exhaust tube (9" total length with filter). Capped @ 1 end. Other end has a 1 1/2" tube inserted along the length with a breather filter. I had some exhaust tube laying around, so, fabbed something up with the MIG welder. It was a fair amount of welding. 4th gen F_bodies sure don't have alot of space and usually require custom.

 

This may be in a bit into left field, but what design did you mimic for the centrifugal oil/air separator? I originally pictured something similar to a vortex protein-skimmer used in aquariums, or more recently in high-end home vacume cleaners.

Interesting idea... most of the vacume pumps I've seen just use a baffled catch can like you mentioned.

I'm awefully tempted to slap a vacume pump on my 396 w/6" rods and 12.5:1 compression. Probably not as big of gains as a blower car would see, especially since it's ring-gapped for NA use, but I'm curious if the large displacement, longer dwell time (6" rod) and high compression can still see some benefits from pulling 15" from the crank case.

Ideally I'd just wait and go dry-sump, lower the engine an inch or so, and tuck it farther back to the center of the car as well... but that's obviously a major project for someone who just got the car on the road 2 months ago. I need a summer off. (maybe just a stereo upgrade, or heated seats).

But a vacume pump seems pretty straight forward... weld on some vaccume ports in the valve covers, mount a pump to the AIR Pump slot, etc... not cheap, but it may be worth the ponies.

 

One more question... (in addition to the design-style of that fancy catch can)... do you have low-tension rings in your motor?

I have a 1/16, 1/16, 3/16 ring package (not low tension) with NA gapping for longitivity on the street. I've read several debates online about the benfits of a vacume pump for NA, standard tension rings.

Did you measure crank case pressure with the pump off? What's the max pressure it's set to pull? (i assume you have a valve limiting the max pressure).

I assume you wouldn't care about vacume at idle and cruise, as there shuoldn't be much blow-by and any vacum you pull is probably just loading the engine unnessesarily. Is there any way to tune the vacume curve (outside of buying smaller/larger pumps and adjusting the max pressure via a valve?).

Definite conversation piece.

Anyone know if large turbo diesels benefit from a vacume pump? Seems like an obvious upgrade to a Duramax pick-up or a long-haul rig.

 

I have std tension plasma moly rings on JE -28cc bower pistons. The vac pump receiver is based on industrial fugative dust separator designs I have done in the past.

As an Engineer, I don't really understand why a linear baffeled design is used in most aftermarket products. Oil (in mist form) is not easy to separate with a linear flow design. Vessel geometry cannot maintain high air velocity required for oil separation. I dropped $80 dollar for the one I purchased. Maybe I can sell it. I've found it does not work well for my application.

In the past, I used a VAC port on the blower suction side for crancase vac. Over time, some oil would still pass thru and make a mess of everything. That was with use of a baffeld catch can/ so-called separator. As reinterated, these designs do not maintain high air velocity for oil extraction. Some (most) of the oil mist is separated in the intercooler and intake manifold and create a mess before combustion chamber injestion. They also do not move adequate volumes of air from the crankcase.

I also designed/ fabed my own regulator. Could not find one that fitted my engine configuration. @ present, I have it adjusted @ 12" Hg vac for a wet sump oil system. Dry sumps can handle higher vac levels.

GZmotorsports has alot of information on vac pump application. I got many ideas (and parts) from these people. B.

 

you get any pics of this ????

 

Photobucket.com Ref LT1...

 

i'll try try that ,,no link ??

 

crap ,,,,,,,,,,,