Found a huge vacuum leak. Probable cause?

[94mstng94]

Uh, dowhut? Any unmetered air will affect a/f

My point is for him to monitor a/f at idle to locate and remedy his vacuum leak.

[91CoupeMike]

14:1 IS LEAN

Mike, you need to eat a snickers, you aren't paying attention again.

Ok correct me if I'm wrong.

But isn't e10 gas stoch at 14:1?

At wot I'm at 12.5-12.8.

Idle is about 15:1

[crapstang]

I heard someone mention massively blown head gaskets. Weird.

[racrguy]

Ok correct me if I'm wrong.

But isn't e10 gas stoch at 14:1?

At wot I'm at 12.5-12.8.

Idle is about 15:1

Where you want it, if not a little richer because alcohol fuels need more fuel to the same amount of o2. My sprint car is in around 4.5-4.7:1 ratio, if that gives you any indication.

[91CoupeMike]

Where you want it, if not a little richer because alcohol fuels need more fuel to the same amount of o2. My sprint car is in around 4.5-4.7:1 ratio, if that gives you any indication.

I think e85 is like 10:1 but I'd have to check.

So my real question to this is, how would you guys run a pcv system? Or would you?

I'm still toying with the idea of a low pressure vacuum pump, I'm sure at high rpm at 203k miles I have blow by, something simple to pull pan vacuum would be nice.

Or should I just cap it and run a breather filter in place of the pcv?

[YALE]

You should run a pcv, and not an open breather, and then fix whatever little vacuum leaks you find, then get it tuned. If your current tune is attempting to accommodate that wonky setup, you're probably leaving a little power and a lot of drivability on the table. You don't need a vacuum pump. You aren't running a .600"+ lift cam with an auto with a big stall, or a dry sump system. Your brakes will be more reliable, too, with the vacuum system in place. Do not step over a dollar to pick up a dime, dude. Or do. It's your car. Just remember us when Guiness calls because you have broken the record for the world's most expensive 300hp small block setup.

[91CoupeMike]

You should run a pcv, and not an open breather, and then fix whatever little vacuum leaks you find, then get it tuned. If your current tune is attempting to accommodate that wonky setup, you're probably leaving a little power and a lot of drivability on the table. You don't need a vacuum pump. You aren't running a .600"+ lift cam with an auto with a big stall, or a dry sump system. Your brakes will be more reliable, too, with the vacuum system in place. Do not step over a dollar to pick up a dime, dude. Or do. It's your car. Just remember us when Guiness calls because you have broken the record for the world's most expensive 300hp small block setup.

Working on the funds for a dart 363 so anything I buy now will be helpful later on.

But I get what you're saying.

I was more worried about crankcase pressure at high rpm. A lot of things I've found and read say one of the most important things to monitor is pan vacuum.

[YALE]

That's fine. If it's a street build, you should still run a pcv system. Getting those fuel vapors out of your crank case is important for oil longevity and therefore engine longevity.

[shumpertdavid]

Unless you're going to drop the coin on a purpose built scavenging pump, you're not going to see any real benefits with a vacuum pump system. I looked into doing a couple of SHO smog pump for a setup. It didn't matter if it was a single pump or both tied together, they'd only pull around 3 inches of vacuum. This was the pumps connected directly to a vacuum gauge. There's no way they'd give much benefit when trying to battle against any type of pressure. While you could try a basic engine driven vacuum pump, the vanes in the pump won't take the oil residue for any amount of time before coming apart. A belt driven purpose built evac setup will run you a grand or better last time I check. It will pull 10 plus inches of vacuum under high rpm and crankcase pressure, requires a regulator be installed to keep it from pulling excessive vacuum, and isn't really designed for long term street use. An old school set of exhaust scavengers can also be used, but I'm not sure they'd like being run long term in street use either. As all have stated above, keep it simple and easy.

[91CoupeMike]

Unless you're going to drop the coin on a purpose built scavenging pump, you're not going to see any real benefits with a vacuum pump system. I looked into doing a couple of SHO smog pump for a setup. It didn't matter if it was a single pump or both tied together, they'd only pull around 3 inches of vacuum. This was the pumps connected directly to a vacuum gauge. There's no way they'd give much benefit when trying to battle against any type of pressure. While you could try a basic engine driven vacuum pump, the vanes in the pump won't take the oil residue for any amount of time before coming apart. A belt driven purpose built evac setup will run you a grand or better last time I check. It will pull 10 plus inches of vacuum under high rpm and crankcase pressure, requires a regulator be installed to keep it from pulling excessive vacuum, and isn't really designed for long term street use. An old school set of exhaust scavengers can also be used, but I'm not sure they'd like being run long term in street use either. As all have stated above, keep it simple and easy.

The one was looking at were about $700

http://www.gzmotorsports.com/CPVK102-vacuum-pump-kit.html

Worth it if you need it.

What about tapping into the header? What draw back would that have?

[shumpertdavid]

Nice price for the setup

[greenbullitt]

Ok correct me if I'm wrong.

But isn't e10 gas stoch at 14:1?

At wot I'm at 12.5-12.8.

Idle is about 15:1

You realize that stoich on your wideband is 14.7 right?

[majorownage]

Ya the wideband works off lambda then it multiplies by 14.7 to get afr. So a stochi mix of alcohol will still be displayed as 14.7 on the gauge.

I say delete all the PCV shit and just vent to the blow-by to the atmosphere.

[YALE]

The one was looking at were about $700

http://www.gzmotorsports.com/CPVK102-vacuum-pump-kit.html

Worth it if you need it.

What about tapping into the header? What draw back would that have?

That is a mighty if.

[sickpony]

Valve cover breathers.