evac setup with vibrant race mufflers will it work ?

was wondering if this setup would work with race mufflers , if i dont have to spend money for vacum pump i dont want to right now . building a 523 around 13.1 compression should make 675 to 700 Hp ....

i see this setup ran on a lot of old dragsters ect ... wondering if it work for me

and any idea how much vac these will draw ?

Thanks
Andrew

Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

so dont do it in the collector do it right after the muffler

and wonder how much it will draw?

rmcomprandy wrote:Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

That's an interesting reply Randy! I would have answered differently, maybe wrong! If a true low/no restriction muffler was in place would the vacuum produced by the engine's exhaust provide adequate vacuum prior to the muffler? If a muffler is restrictive, does the engine's exhaust speed slow after the muffler, given all diameters are equal?

Dave.

mufflers are 5inch long and by no means restrictive just enuff top pass tech for a muffler

LivermoreDave wrote:

rmcomprandy wrote:Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

That's an interesting reply Randy! I would have answered differently, maybe wrong! If a true low/no restriction muffler was in place would the vacuum produced by the engine's exhaust provide adequate vacuum prior to the muffler? If a muffler is restrictive, does the engine's exhaust speed slow after the muffler, given all diameters are equal?

Dave.

in the collector ,

its the flow pass the tube that creates the vacuum

I have mine in the collector. I've run mufflers (dynomax ultraflo's) but currently don't. Mine worked the same either way. Really good vacuum draw even at 1100rpm idle. I like them because they are simple and work.

never used before is there a way to tell how much vac its drawing ......do ya use a gauge ?

No I didn't use a gauge so nothing measured/scientific here. My evac hose is AN12 braided. Just saying I could feel good suction when I disconnected it from the top of the valve cover even at idle. FWIW

Oh yea. Just wanted to say if you go getting one from Moroso (or where ever I guess) check your evac valves before install. Be sure they flow adequately in the direction they are supposed to and not at all the other way. I bought a kit and had a faulty brand new valve once. Wouldn't move air either way.

5pointslow wrote:never used before is there a way to tell how much vac its drawing ......do ya use a gauge ?

That's interesting you had that idea! I almost wrote that in my original reply. One could check vacuum levels simply by locating a valve such as used in the exhaust vacuum system, before the muffler and after then attach a vacuum gauge(s).

Dave.

LivermoreDave wrote:

rmcomprandy wrote:Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

That's an interesting reply Randy! I would have answered differently, maybe wrong! If a true low/no restriction muffler was in place would the vacuum produced by the engine's exhaust provide adequate vacuum prior to the muffler? If a muffler is restrictive, does the engine's exhaust speed slow after the muffler, given all diameters are equal?

Dave.

I did a bunch of testing for the Engine Masters of where to put the DRAW pipes.
Now this is only a 331 inch engine so the volume of exhaust air is not near as much.
With NO mufflers there was just under an inch of vacuum in the pan ... removing the one way valves, (under the presumption that it wasn't gonna backfire), raised the vacuum pull to almost 3 inches.
Put straight through Magnaflow mufflers on the pipes and there was NO vacuum in the crankcase at all.
Disconnected both and T'd them together with a line to the dyno vacuum gauge and made a run. All the way through the run the vacuum wandered between 1 inch to zero to 1 inch of pressure so we put the one way valves back on. Now there was nothing at the gauge, one way or the other.
Made up some 12" extensions to put after the mufflers with draw tubes the same as in the header collector.
Wouldn't you know it, the crankcase vacuum was again what it was reading without mufflers.

WE were overjoyed thinking we found something which other EMC competitors hadn't but, THEN the magazine people changed the rules to now THEY were going to supply the "mufflers back" exhaust system for everyone.
Then we put draw tubes in every primary header tube 3" downstream from the flange similar to an AIR system with a tubing manifold which was the best but, still only an inch of crankcase vacuum with the mufflers in place.

"When testing, if the results differ from your theory ... BELIEVE the results and invent a new theory".

rmcomprandy wrote:Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

I have tried them both ways on the dyno in the last few years ,and after the muffler works best

Made a discovery on the chassis dyno a couple years ago.
I had the Moroso pan evac system back then in the collectors as per the instructions.
After the headers I have a 3.5" H pipe, Hooker Aerochamber mufflers just ahead of the axle and 3" tail pipes to the bumper.
After tuning the motor we pulled the pan evac breathers off for a final pull... PICKED UP 10 RWHP !
They seem to be ineffective and detrimental to a full exhaust equipped vehicle.

rmcomprandy wrote:

LivermoreDave wrote:

rmcomprandy wrote:Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

That's an interesting reply Randy! I would have answered differently, maybe wrong! If a true low/no restriction muffler was in place would the vacuum produced by the engine's exhaust provide adequate vacuum prior to the muffler? If a muffler is restrictive, does the engine's exhaust speed slow after the muffler, given all diameters are equal?

Dave.

I did a bunch of testing for the Engine Masters of where to put the DRAW pipes.
Now this is only a 331 inch engine so the volume of exhaust air is not near as much.
With NO mufflers there was just under an inch of vacuum in the pan ... removing the one way valves, (under the presumption that it wasn't gonna backfire), raised the vacuum pull to almost 3 inches.
Put straight through Magnaflow mufflers on the pipes and there was NO vacuum in the crankcase at all.
Disconnected both and T'd them together with a line to the dyno vacuum gauge and made a run. All the way through the run the vacuum wandered between 1 inch to zero to 1 inch of pressure so we put the one way valves back on. Now there was nothing at the gauge, one way or the other.
Made up some 12" extensions to put after the mufflers with draw tubes the same as in the header collector.
Wouldn't you know it, the crankcase vacuum was again what it was reading without mufflers.

WE were overjoyed thinking we found something which other EMC competitors hadn't but, THEN the magazine people changed the rules to now THEY were going to supply the "mufflers back" exhaust system for everyone.
Then we put draw tubes in every primary header tube 3" downstream from the flange similar to an AIR system with a tubing manifold which was the best but, still only an inch of crankcase vacuum with the mufflers in place.

"When testing, if the results differ from your theory ... BELIEVE the results and invent a new theory".

whats to best way to install these? just like the instructions or turn the draw pipes around with the opening facing towards the exhaust exit , thanks

10SHOTS wrote:

rmcomprandy wrote:

LivermoreDave wrote:

rmcomprandy wrote:Just be sure to plumb the the outlets AFTER the mufflers in a high velocity part of the exhaust pipe.

That's an interesting reply Randy! I would have answered differently, maybe wrong! If a true low/no restriction muffler was in place would the vacuum produced by the engine's exhaust provide adequate vacuum prior to the muffler? If a muffler is restrictive, does the engine's exhaust speed slow after the muffler, given all diameters are equal?

Dave.

I did a bunch of testing for the Engine Masters of where to put the DRAW pipes.
Now this is only a 331 inch engine so the volume of exhaust air is not near as much.
With NO mufflers there was just under an inch of vacuum in the pan ... removing the one way valves, (under the presumption that it wasn't gonna backfire), raised the vacuum pull to almost 3 inches.
Put straight through Magnaflow mufflers on the pipes and there was NO vacuum in the crankcase at all.
Disconnected both and T'd them together with a line to the dyno vacuum gauge and made a run. All the way through the run the vacuum wandered between 1 inch to zero to 1 inch of pressure so we put the one way valves back on. Now there was nothing at the gauge, one way or the other.
Made up some 12" extensions to put after the mufflers with draw tubes the same as in the header collector.
Wouldn't you know it, the crankcase vacuum was again what it was reading without mufflers.

WE were overjoyed thinking we found something which other EMC competitors hadn't but, THEN the magazine people changed the rules to now THEY were going to supply the "mufflers back" exhaust system for everyone.
Then we put draw tubes in every primary header tube 3" downstream from the flange similar to an AIR system with a tubing manifold which was the best but, still only an inch of crankcase vacuum with the mufflers in place.

"When testing, if the results differ from your theory ... BELIEVE the results and invent a new theory".

whats to best way to install these? just like the instructions or turn the draw pipes around with the opening facing towards the exhaust exit , thanks

We tried them both ways.
1. When just a 1/4" in the collector and the bologna sliced tube at 45 degrees with the slice "in line" with the collector, produced the highest amount of vacuum but, ONLY at higher exhaust air speeds. (With that 331 it was well above 4,000 RPM).
2. with the bologna slice facing the back opening of the collector it saw vacuum MUCH sooner but, only about 2/3 as much at high air speeds as the other way.

In conclusion ... both ways work depending upon WHERE and HOW MUCH vacuum, (Total or Average), you wish to see. The size of the engine, (each gulp of air), and the RPM, (the amount of air speed), will have a giant affect upon what vacuum the tube will give.

On my car with evacs in the collectors, Hooker Maxflows, h pipe and 3" pipes dumped, they were pulling nice vacuum at idle, but once the exhaust backpresure came up with rpm, it ceased being helpful.