Login    Forum    Search    FAQ

Board index » Racing Forum » Fuel Systems




Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post Posted: Fri Sep 21, 2012 6:25 pm 
Offline
User avatar

Joined: Mon Sep 10, 2012 4:08 pm
Posts: 39
lets delve into this ...
old combo on single turbo blowthru gas carb worked good with low boost and no meth inj.
was using 50/50 h2o/meth for cooling at high boost 22+
started logging iat numbers and showed hot air and tad lean
upped % to 30/70 and iat, egt and o2 got safer .
upped the nozzle sizes to 3 x.015. got better but still not happy side of fat
figured throw the sink at it went 100% methanol and upped psi
now heres whats funny every time boost came up and pump kicked in the iat dropped the egt went up. o2 showed lil rich then way lean and popped back . one time it coughed so hard it blew off carb stud to hat .... this stopped when i diluted the mix back down .
by my understanding that methanol will vaporize and cool the inlet temps and add fuel .. .
the water that vaporizes wont burn and acts to cool cyl temp acting as a egr .
there were no signs of detonation on pistons and rings. or fuel puddling in ring lands .
i only theorizes that what i have is the mix was in that long tube that it cooled so fast that there was not enough jet and gas to cover the big hole in the afr .and it spiked lean and missfired ?
so is it possible to inject such a fine mist of high psi methanol into a air inlet to drop the charge temp so much to cause this even though it was a fuel ?

_________________
Image


Top 
 Profile  
 
 Post Posted: Fri Sep 21, 2012 11:05 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
You need to have the carburetor supply enough fuel across the range, then you know the AFR will be correct. If you use the injector cooling system to do it you only have a given amount of fuel so it will only be right at one point in the rev range.


Top 
 Profile  
 
 Post Posted: Fri Sep 21, 2012 11:21 pm 
Offline
User avatar

Joined: Sat Feb 07, 2009 4:12 pm
Posts: 1215
Location: Adelaide Australia
The issue with popping etc when running straight methanol and not getting it when mixed with water is likely to be your too lean. Methanol or any fuel for that matter cannot burn beyond its lean explosive limit. methanol in particular can burn without damage at very lean settings. when you have water mixed you wont get much of the fuel to actually burn because water increases the extinguishing size of methanol droplets. When you ran straight methanol you then increased the mixture strength to something that was burnable but still too lean.
Forget about readings from a WB that could be anywhere with this stuff. The water content will send the WB toward stoich. In fact you can put a WB into the steam stream from a kettle and you will get a 14.7 AFR reading.


Top 
 Profile  
 
 Post Posted: Sat Sep 22, 2012 12:24 am 
Offline

Joined: Mon Apr 30, 2012 10:01 pm
Posts: 140
Shrinker, back on line. Hope your health is good.


Top 
 Profile  
 
 Post Posted: Sun Sep 23, 2012 5:46 am 
Offline
User avatar

Joined: Mon Sep 10, 2012 4:08 pm
Posts: 39
THAT WAS IT ? figured that o2 was being fooled on h20 and just lucky on detonation .
or that the drastic drop in inlet temp created a need for even more fuel that even the added methanol could not cover with carb being on the lean side . or both
think i need to revisit the csu carb again . now that this pig is inter-cooled.
and a better turbo . maybe i'll try my carb ,it was always rich and tuneable with 2 brpvs
it was a driveabilty and staging pita . but alas
first/ last pass out Rick broke the phaseable rotor and the divider in the waste-gate pipe .
nothing hurt just sounded awfull ran crappy and pride damaged

Any other thoughts

_________________
Image


Top 
 Profile  
 
Display posts from previous:  Sort by  
 
Post new topic Reply to topic  [ 5 posts ] 

Board index » Racing Forum » Fuel Systems


Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron