Measuring heatsoak vs actual AIT? - Page 6 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Race Prep Miata race-only chat.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 03-20-2016, 04:25 PM   #101
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,459
Default

Those intercooler sprayers spray water on the intercooler. Not into it.
aidandj is offline   Reply With Quote
Old 03-20-2016, 04:25 PM   #102
Junior Member
iTrader: (5)
 
Join Date: Oct 2014
Posts: 473
Total Cats: 23
Default

Yeah, I corrected my statement. You are just mad fast.
90civichhb is offline   Reply With Quote
Old 03-20-2016, 04:49 PM   #103
Sadfab Union President
iTrader: (3)
 
Join Date: May 2014
Location: Kansas
Posts: 2,690
Total Cats: 113
Default

Knowing absolutely nothing about water injection, I'd expect you'd want the water nozzle as close to the outlet of the compressor as possible, give the water plenty of time to change phase and soak up heat.

And IAT always goes post intercooler, either endtank or plumbing directly after endtank, outside engine bay. As expected, Aidans test shows that in steady even air temps the case of the sensor will skew temps bad. There's nowhere else you can put it.
deezums is offline   Reply With Quote
Old 03-20-2016, 04:54 PM   #104
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,184
Total Cats: 2,582
Default

the water will provide biggest effect inside the combustion chamber
and I wouldn't want it cooling down the sensor anyway, rather be running too safe than artificially "safe"
18psi is offline   Reply With Quote
Old 03-21-2016, 12:59 AM   #105
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by deezums View Post
Knowing absolutely nothing about water injection, I'd expect you'd want the water nozzle as close to the outlet of the compressor as possible, give the water plenty of time to change phase and soak up heat.
Based upon studies done by NACA (the predecessor to NASA) during the 1940s, the optimum place for the water nozzle, in terms of combating knock due to insufficient octane, is inside the combustion chamber ala direct-injection.

This is hard to do.

Last edited by Joe Perez; 03-21-2016 at 02:01 AM. Reason: grarmmer
Joe Perez is offline   Reply With Quote
Old 03-21-2016, 01:00 AM   #106
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,459
Default

I believe in the runners is the second best place. From my minimal water/meth injection research. Look up direct port meth injection.
aidandj is offline   Reply With Quote
Old 03-21-2016, 01:06 AM   #107
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

The key point being simply that the water does most of its work inside the chamber during the compression cycle. Relatively little evaporative cooling occurs in the intake plumbing or the plenum.

You want as much of the water as possible to still be finely atomized when it enters the chamber. The further upstream you inject it, the more likely it is to pool out of atomization into larger droplets, especially if an intercooler is present.
Joe Perez is offline   Reply With Quote
Old 03-21-2016, 01:08 AM   #108
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,184
Total Cats: 2,582
Default

yup, exactly where I was going with that

that's why I'm always a bit surprised (and skeptical) when people claim their AIT's magically plummet with w/i and no intercooler
18psi is offline   Reply With Quote
Old 03-21-2016, 01:38 AM   #109
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,459
Default

Well the water probably cools the sensor...
aidandj is offline   Reply With Quote
Old 03-21-2016, 01:40 AM   #110
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,184
Total Cats: 2,582
Default

and they think their charge is legitimately below ambient
18psi is offline   Reply With Quote
Old 03-21-2016, 11:32 AM   #111
Junior Member
iTrader: (5)
 
Join Date: Oct 2011
Location: San Diego, CA
Posts: 402
Total Cats: 21
Default

Quote:
Originally Posted by 90civichhb View Post
So to further a bit on the water/meth injection idea. Would you want to place the nozzle before the AIT sensor? For instance would placing it in the "hot side" of the intercooler endtank be a good place for it? I know some cars come OEM with intercooler sprayers like the EVO and some Japanese spec STIs but that is external and I've not seen people run it like I mentioned before. Usually it is always near the throttle body.
My GM IAT is in the cold side of the intercooler and my water/meth injection is about 6" from the throttle body.

I'm sure water is probably ok to spray in front of the IAT sensor, but I have a feeling meth probably isn't that great of an idea.

When I'm spraying meth on the streets, I run a special tune for it. And when I'm running only water like at the track, I run a much more mild tune.
slmhofy is offline   Reply With Quote
Old 03-21-2016, 11:51 AM   #112
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

Quote:
Originally Posted by 18psi View Post
that's why I'm always a bit surprised (and skeptical) when people claim their AIT's magically plummet with w/i and no intercooler
you dont e-cool?
Braineack is offline   Reply With Quote
Old 03-21-2016, 11:52 AM   #113
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

Quote:
Originally Posted by aidandj View Post
Well the water probably cools the sensor...
how exactly would that work?
Braineack is offline   Reply With Quote
Old 03-21-2016, 11:58 AM   #114
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,184
Total Cats: 2,582
Default

I d-cool
18psi is offline   Reply With Quote
Old 03-21-2016, 12:46 PM   #115
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,666
Total Cats: 1,560
Default

^He actually V-cools but he has a thick accent.
sixshooter is online now   Reply With Quote
Old 03-21-2016, 12:49 PM   #116
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,459
Default

Quote:
Originally Posted by Braineack View Post
how exactly would that work?
Evaporative cooling on the sensor element? Just spitballin here
aidandj is offline   Reply With Quote
Old 03-21-2016, 01:13 PM   #117
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,666
Total Cats: 1,560
Default

I would be concerned about measuring the air as being warm and then having it actually be cooler and more dense once it is then cooled by the injection. This could inadvertently make the mixture more lean.
sixshooter is online now   Reply With Quote
Old 03-21-2016, 01:20 PM   #118
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,184
Total Cats: 2,582
Default

hmm, so basically it sucks either way.

got it
18psi is offline   Reply With Quote
Old 03-21-2016, 01:39 PM   #119
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

Quote:
Originally Posted by sixshooter View Post
I would be concerned about measuring the air as being warm and then having it actually be cooler and more dense once it is then cooled by the injection. This could inadvertently make the mixture more lean.
unless it's pretty much repeatable and consistent. then the fuel map would just reflect it.
Braineack is offline   Reply With Quote
Old 03-21-2016, 01:43 PM   #120
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by sixshooter View Post
I would be concerned about measuring the air as being warm and then having it actually be cooler and more dense once it is then cooled by the injection. This could inadvertently make the mixture more lean.
Again, there's very little cooling effect happening outside of the combustion chamber. I don't have the data in front of me, it's somewhere in a binder at home full of old photocopied test reports from WW2.

Any cooling (and thus, density increase) which happens inside the chamber during the compression cycle is irrelevant from the standpoint of fuel metering, as it's a sealed volume. More oxygen cannot enter past the closed intake valves.
Joe Perez is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Need various sensors for NB2 ajay842 WTB 5 04-29-2016 04:35 PM
2.5" GReddy down tube with custom FM cat Cxracer Miata parts for sale/trade 24 04-22-2016 06:38 PM
1.6l header and test pipe/ 195 dunlop dz102. Flyinglizard45 Miata parts for sale/trade 0 03-14-2016 09:54 PM
IAT temps... how hot is too hot? umwhat General Miata Chat 22 03-06-2016 12:17 PM
IAT sensor reading high (not heatsoaked) btabor MEGAsquirt 5 02-25-2016 08:44 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 08:19 PM.