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scooter

running side drafts but you want to run a vacuum power booster? no problem!!

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so i was strolling through pick a part today looking for another 71c trans for my car and stumbled across a 720 with a sd22 diesel in it.

 

after seeing what trans it had, i moved on, but there was something different i noticed... and that was THAT THERES A FRICKIN VACCUM PUMP HANGING OFF THE ALTERNATORS BUTT!

 

these are also internally regulated 70 amp alternators as well. so i grabbed it as it looked really minty. So for you guys with side drafts that want power brakes, now you can have vaccuum without messing around with your intake or have your brakes work with a monster camshaft. pretty neat. also very reliable if you run it in the way its intended. this looks like a bolt in if you are set up already with an internally regulated system.

Alternator-for-Nissan-Navara-SD22-SD23-S

 

My plan is to try and pull crankcase vaccuum with it. output to a catch can and block off the oil feed. plumb it into the valve cover sans baffle so it hopefully gets enough residual oil not to have a melt down.  why? because racecar!

 

maybe you guys knew about this allready, but i didn't and thought it was pretty cool.

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But is there enough room to have vacuum canister on brake master with dual Webers ?? 

 

If you get the manual.  SD22 bellhousing i'll give you $200. CAD ,, for it. 

 

 

 

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Edited by bananahamuck
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Getting a Roadster?

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Not enough volume to use as a crank case vacuum pump.

But what a great find for pulling a vacuum for a brake booster !

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I suspect it will not last long, it needs the oil to keep it lubricated, it will work with very little oil as I had a oil feed hose kink, but your talking about feeding very little oil into a completely different area meant to expel oil not let oil in.

They make vacuum pumps for what you are talking about that need no oil that are belt driven or electric driven I believe. 

 

Edited by wayno

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151bc70f-2225-4325-9d99-0f9d8c7a6f65_pum31n0oun1bRL.jpgAC Delco 20804130

 

Some GM vans and trucks had a vacuum booster pump mounted on the brake booster.

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Same pump I have, only came on a Volvo.

(does GM own Volvo now?)

All over eBay. Think I paid like $35 for mine.

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3 hours ago, datzenmike said:

Getting a Roadster?

 

Got a screaming deal on a running driving 65 410 awhile back,, BUT  i also was gifted an old TMC forklifter that the steering box had gone out on it, with an H20.. Figured using the SSS crossmember/ oil pan,  i am getting in a couple days,, and maybe switching valve springs out for stiffer.  And run that bitch with 3:70 maybe 3:50 gears ( and tiny ass tires) with 5speed,,,  iron head , low RPM cam,,,, and all ..  I'm assuming the compression ratio in a Forklift motor is so low i should be able to run it even on sauerkraut juice

At 1500 RPM all day long

 

.I got a couple roadster 4speeders now but was hoping to not run it at that high or rpms.

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Sauerkraut juice will corrode the carb...and make you smell like an old German.

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15 hours ago, bananahamuck said:

But is there enough room to have vacuum canister on brake master with dual Webers ?? 

 

If you get the manual.  SD22 bellhousing i'll give you $200. CAD ,, for it. 

 

 

 

.

Theres two there, ones sitting in the bed and its easy ill go get it

Edited by scooter

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You can get a remote canister to delete the one mounted at the master cylinder. They even make electric pumps with integral canisters.

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If that pump doesnt have enough pull or if it dies right away then ill get a real vaccuum pump for it, i still really like the idea of driving it off the back of the alternator though.

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You would need to close the engine up. Seal the valve cover vent. Seal the block vent and this would disable the PCV.

 

None of those will have the volume I suspect, or they would be larger. What you need is a belt driven air injection pump from an earlier L20B. (they already have mounts made just for them) You would need to filter out any oil or particulates to protect the pump. (I think they are called catch cans) But you would need a really good one, or make one. Maybe something like a bong so it bubbles and that can be emptied regularly)

 

Seems to me the losses turning a pump would barely cover the gains if any.

 

The 720 uses the negative exhaust pulses (just behind the positive ones using a one way only reed valve) to suck air into the exhaust so the catalytic converter has oxygen to work with. You might get a pound or two of vacuum used on the crankcase and it's passive, needs no pump or belt.

 

I see there's a dyno comparison on you tube and I know you can't really scale these things down very accurately but they got 20 extra HP at 7500 on a 460 hp engine. That's only 4% increase. If you look at the readouts, the pull without the pump has 394 hp (@132 sec) at 6k while with the pump, it's 378 hp (at 257 sec) at 6K. So WTF???? I call bullshit on this test which calls into question the 4% gain.

 

So is this like the crank scraper? 3-5 hp at god only knows what RPM?

 

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I didn't catch the part about using the vacuum pump for pulling a crankcase vacuum. I thought you wanted it for power brakes. A lot of diesel engines have them on the alternator, like the Toyota Land Cruisers.

 

Dry sump systems pull a crankcase vacuum. So much sometimes that you can hear the lip seals at the crank flapping like a high pitched reverse fart.

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You find the best power gains at about 15" hg (7 psi), which is also about the limit of shaft seals.

To limit crankcase vacuum level, there needs to me vacuum relief valve somewhere in the system.

I use a GAST AA308 adjustable aluminum vacuum relief valve that I machined the end so that a K&N filter can be attached.

You don't want to be drawing unfiltered air through the crank case.

 

Mike may not understand, but 1% HP gains add up, and do this enough times is what it takes to be a front runner, instead of an also ran.

 

DSC09222.jpg

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it will be interesting to see if i can get any significant pull on the crankcase with it. a super late model  i used to work on had the same relief valve as above, but ran a 5 stage dry sump and pulled all the vaccuum. running a pump on your motor has other benefits too, like keeping oil from weeping out the seals 🙂

 

 

 

 

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