Because it ISN'T an issue ever??Smartparts;1884522 said:
Maybe when there's only 5 litres left in the tank and you brake or corner hard..
charcoal canister delete on the mk3 bad?
- Thread starter 1986.5supra_kid
- Start date
Maybe when there's only 5 litres left in the tank and you brake or corner hard..
Correct me if I'm wrong here. I've understood cavitation to be when fluid sees sudden low pressure, causing the fluid to boil monetarily and creating a pocket of vapor.
The low pressure is typically caused by a pump trying to pull more than the fluid allows or a sharp bend in flow path
Right?
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The low pressure is typically caused by a pump trying to pull more than the fluid allows or a sharp bend in flow path
Right?
Sent from my Galaxy Nexus using Tapatalk 2
This topic has been covered many times. I started a thread a while back with my attempt to replace the factory system with a small charcoal canister and 2psi check valve. Apparently I did it wrong. Still not sure why, as it appears to be working fine for me. There's good info in the thread, perhaps you'll have a better understanding of it than I.
http://www.supramania.com/forums/sh...er-install-*PICS*&highlight=charcoal+canister
http://www.supramania.com/forums/sh...er-install-*PICS*&highlight=charcoal+canister
suprarx7nut;1884753 said:
This is what I know cavitation as. and don't forget the bad part, when that pocket of vapor disappears and the fluid around in comes crashing down with tremendous force. I have a feeling that something else is meant by cavitation as it is being used here.
If you want to understand this learn about NPSHA, that's net positive suction head available. The likelihood of cavitation in this application is not great, but given the right fuel temps, elevation and high demand it can happen.
Tech Article #62 on Autoshop101.com (which explains the evap system well and is reprinted from Toyota factory training materials) as well as every TCCS manual I own state the slight positive tank pressure is there specifically to reduce pump cavitation due to fuel vaporization. The books further state check valve #2 in the evap cannister is what maintains that pressure. Fwiw...
IJ.;1884889 said:Thanks JJ, learnt something new
I know mate. It's one reason you're so damn good at this.
Some in this thread would do well to carefully read #61 too...
This post reminds me that I have an off topic post to write up on the subject. Thanks 3p!3p141592654;1883962 said:
As always with the vague posts haha... I am curious where your interest lies in the subject then. Only other thing I haven't seen mentioned is that if you just remove the canister but don't vent the line somewhere away from your engine bay (exhaust side at that!), you're letting fumes build up under your hood, in the hottest area of the engine bay...jetjock;1883949 said:
I would love to know this as well, not too easy to shop for 1jz OEM parts in this part of the world.z4ck;1884927 said:
I read through that tech article that jetjock posted, and in the testing of the evap system, it mentions that a properly functioning system should flow around 25L. My question then, or more a confirmation rather, do they mean 25L of air/fuel vapor? If that is the case, then that could actually improve fuel economy a decent amount to have a properly functioning system!
Adding a CC to the list of crap to make sure we have for the 87 when we get started...
Emissions aside it should be obvious that venting paid for fuel overboard, even as vapor, rather than combusting it is dumb. Especially at today's prices. Gotta have that clean engine bay to impress, well, someone though. Not sure who.
Way way back when I was a munchkin (about 42 years ago) my Father had a 1964 Holden that had a 179Ci I-6, they had a "walking stick" breather from the Rocker Cover down the side of the engine that would vent under the car...
We fitted it with a new fangled PCV valve and hose and fuel economy took a leap not to mention the smell of oil and fumes were gone making long drives much nicer (I got car sick as a kid)..
Always makes me laugh when people "clean up" engine bays with NFI what the systems they're removing do!!
Here in Australia back in 1976 they introduced ADR27a which was emissions control on all new engines.. DISMAL Failure and it destroyed performance/economy/driveability and was something that should have been "cleaned up"
By Mid 80's car companies started to get it right, Toyota did a great job, Fast forward to today and the current crop of factory performance cars are stunning by comparison!
We fitted it with a new fangled PCV valve and hose and fuel economy took a leap not to mention the smell of oil and fumes were gone making long drives much nicer (I got car sick as a kid)..
Always makes me laugh when people "clean up" engine bays with NFI what the systems they're removing do!!
Here in Australia back in 1976 they introduced ADR27a which was emissions control on all new engines.. DISMAL Failure and it destroyed performance/economy/driveability and was something that should have been "cleaned up"
By Mid 80's car companies started to get it right, Toyota did a great job, Fast forward to today and the current crop of factory performance cars are stunning by comparison!
Very much agreed IJ. Although I will say that my buddy's FC RX7 picked up quite a bit of response as a result of removing its emissions bits, and oddly enough, his fuel economy has been surprisingly decent for a rotary that isn't treated kindly.
I'd have to look it up, but I remember GM making a V8 back in the early smog control days that made less than 100HP :3d_frown:
This thread made a right turn somewhere, but on the topic of emission control history, it was 1975 when California CARB emission standards forced most automakers (except Honda's CVCC) to use the first two-way (or oxidation) catalytic converters. I can remember a trip to England some years later and couldn't believe that the cars had next to no emission controls at that time (late 70's) and the stench was appalling. They were still using leaded gas as well!