Those running Evans at zero pressure look - quick question

Reply Subscribe

Thread Tools

Search this Thread

Apr 20, 2005 | 02:04 PM

#26

weaklink

Resident Retard

Joined: Apr 2001

Posts: 1,918

Likes: 0

From: Cockaigne

Quote:

Originally Posted by Mike Nola

The properties of Evans Coolant compared to pure water and 50/50 water/antifreeze can be found here:
http://www.evanscooling.com/html/tech1.htm#ptbl1

I seem to have been misunderstood, i didn't say don't use evans i said don't use a zero pressure system, which also seems to be the recommendation of the manufacturer of Evans, and the recommendation of people who have run at zero pressure.

Do what you wanna.

yes but your intimation of not using aero pressure was because it lowers the boiling point. not an issue with evans.

Quote:

Originally Posted by Mike Nola

Lowering the pressure also lowers the boiling point. Zero pressure cooling system in a car famous for cooling issues with an engine design infamous for intolerance to overheating sounds like trouble to me

Mike

plenty of people are running 0 psi with no problems. in the link you provided, there's no mention of 7 psi or even low psi. It's 15 psi and 0 psi. I think evans includes a recomendation for a low pressure cap as a "Cover Your ***" measure.

Apr 21, 2005 | 11:15 AM

#27

Scrub

bow leggin'

iTrader: (25)

Joined: Jul 2002

Posts: 6,061

Likes: 5

From: Delaware

When I ran 0 psi the coolant would leak out of the top from time to time....the smell got old real quick. I am now running a 14psi cap because I couldn't find a 7psi one.....anyone know where a 7psi cap can be found?

Thanks,
Dan

Apr 21, 2005 | 02:15 PM

#28

KevinK2

Rotary Enthusiast

Joined: Dec 2001

Posts: 1,209

Likes: 6

From: Delaware

Quote:

Originally Posted by DaveW

Just a general note:

Any fluid will cavitate if the minimum pump inlet or internal pressure drops to near the fluid's vapor pressure at that temperature. Even if the fluid's vapor pressure is very low, near zero absolute pressure, a pressure cap will add a margin of safety against cavitation and loss of cooling efficiency.

Several previous posts have mentioned additional benefits of pressurizing the coolant, so, IMO, it would be safer to use, say, a 7-psi cap, even with the Evans coolant.

Given that the VP of evans is about 70mm hg at 250F, or about 1.5 psi absolute, you would need a pressure drop of 13.2 psi across rad to risk cavitation at the impeller inlet, using 0-psi cap at the filler neck. Lower rad hose would collapse with much less drop across the rad. I still think 0-psi and npg+ has no cavition issues, even with extra 1 or 2 psi drop at the impeller ID. I do agree that for other reasons, good to use a 7 psi cap.

Apr 21, 2005 | 03:48 PM

#29

GooRoo

93-FD

iTrader: (4)

Joined: Jul 2002

Posts: 803

Likes: 6

From: Minneapolis, MN

Quote:

Originally Posted by Scrub

When I switched to Evans I found a 7psi cap (for my Pettit AST) at the local NAPA.

Took the guy quite a while to figure out that:

a) I didn't have the stock AST and
b) That I really wanted to run lower than stock pressure

But we eventually found something that fit.

Apr 21, 2005 | 04:03 PM

#30

jimlab

Super Snuggles

Joined: Feb 2001

Posts: 10,091

Likes: 34

From: Redmond, WA

Quote:

Originally Posted by Scrub

anyone know where a 7psi cap can be found?

Evans sells both a 0 psi cap (PN E2002), and a 7 psi cap (PN E2007) for $7.95 each.

Apr 21, 2005 | 04:07 PM

#31

Tom93R1

gross polluter

iTrader: (2)

Joined: Mar 2001

Posts: 1,757

Likes: 25

From: Chandler, AZ

Many aftermarket AST's run the standard size radiator cap. That makes it really easy to find a 7psi. I wanted to go with something a bit lower like 5 but I couldnt find that in the 10 minutes I spent looking.

Apr 21, 2005 | 04:08 PM

#32

scotty305

~17 MPG

iTrader: (2)

Joined: Jan 2004

Posts: 3,478

Likes: 334

From: Bend, OR

To those running Evans, has it eliminated the "coolant burbling" sound near the stock turbochargers?
-s-

Apr 21, 2005 | 09:38 PM

#33

neit_jnf

Thread Starter

Eats, Sleeps, Dreams Rotary

iTrader: (17)

Joined: Apr 2003

Posts: 4,057

Likes: 262

From: Around

stock cap size?? my aluminum ast uses the stock cap...

Quote:

Originally Posted by jimlab

Evans sells both a 0 psi cap (PN E2002), and a 7 psi cap (PN E2007) for $7.95 each.

Apr 21, 2005 | 09:52 PM

#34

Scrub

bow leggin'

iTrader: (25)

Joined: Jul 2002

Posts: 6,061

Likes: 5

From: Delaware

Quote:

Originally Posted by jimlab

Evans sells both a 0 psi cap (PN E2002), and a 7 psi cap (PN E2007) for $7.95 each.

are those meant for the AST or the filler neck? I got rid of the AST a while ago.

Thanks,
Dan

Apr 21, 2005 | 10:04 PM

#35

jimlab

Super Snuggles

Joined: Feb 2001

Posts: 10,091

Likes: 34

From: Redmond, WA

Quote:

Originally Posted by Scrub

are those meant for the AST or the filler neck? I got rid of the AST a while ago.

Filler neck... most other cars don't use/need ASTs...

Apr 22, 2005 | 03:59 AM

#36

damian

DDH Motorsports

iTrader: (2)

Joined: May 2002

Posts: 4,256

Likes: 21

From: Minnesota

Quote:

Originally Posted by 7racer

damian does and runs Zero pressure on both his track and street car. If I remember correctly, he doesn't have the the "weep hole" mod nor the not having a thermostat as the Evans website suggests.

maybe he'll drop someone can PM to comment in this thread...

Maxcooper recently switched but I'm not sure if he is running zero pressure

yup, i run evens at 0 pressure in both cars, no ast in either car, no wheep hole mod, running standard thermostat

I have no cooling issues in either car.... and I drive them both very hard.