Drain flange - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 03-05-2008, 07:44 PM   #21
Supporting Vendor
Thread Starter
iTrader: (3)
 
Join Date: Jul 2006
Location: San Diego
Posts: 2,865
Total Cats: 493
Default

I would expect that the pre-turbo injection's effectiveness would have more to do with exactly what you are saying about the temp change (how'd you do a delta symbol? Nice.) in the cylinders - as air is being compressed above atmospheric by the turbo just as it is in the cylinder head.

I agree it would not make sense to expect a significant enough heat transfer just from the water traveling through the tubes - which is why injection is usually done at the throttle body, or even with some set-ups I've seen, in the individual runners just before they meet w/ the head.

But perhaps the water vaporizes in the turbo as the air is compressed, basically doing exactly what it does in the cylinder head, combating the rise in temperature from compression. If so, I would expect you would get a substantially cooler mixture exiting the turbo? But hey, I'm dealing all in theory - I really don't know what I'm talking about.

-Ryan
ThePass is offline   Reply With Quote
Old 03-05-2008, 08:26 PM   #22
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,328
Total Cats: 1,926
Default

The theory is sound, and in fact some supercharger owners have done just this. But of course the lobes in the supercharger are turning much, much more slowly than the wheel in a turbo.

When visualizing the tendency of compression to generate heat and thus promote the vaporization of water, consider the pressure ratios (and thus the heat ratios) involved. The pressure ratio of a totally bad-*** turbocharger setup is maybe 2:1, and that's sufficient to generate >200F temperatures. The compression ratio of a typical Miata engine is, what, 9:1 to 9.5:1? Lot more heat generation going on inside the chamber than in the turbo. I wonder what the actual temperature is inside the average N/A combustion chamber just prior to ignition? I tried figuring it out with Gay-Lussac's Law, and for an input temperature of 100F and a pressure ratio of 9:1 I keep coming up with 2700K, which is 4400F. That can't be right...

Is there a chemist in the audience?
Joe Perez is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 12-15-2017 09:00 PM
Another Cast Manifold Corky Bell Prefabbed Turbo Kits 18 11-22-2016 10:01 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM


Thread Tools

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 03:19 AM.