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Cool air affect on mixtures

2K views 11 replies 4 participants last post by  STROKEXD 
#1 ·
Maybe someone knows this answer.

If your clevo goes a lot harder in cool nightime air, more than just the temp drop would normally give you, then is it a sign that the fuel mixture is a bit rich. ie compensates with cool air which is denser and runs relatively leaner and produces more power?

Does that make sense?
 
#2 ·
As you've addressed, there are 2 issues at hand. Cold air is more dense and would normally require upsizing jets to keep your optimum AFR constant. So if you're saying that you're getting an extra ordinary hit on a cold night, then yes, you could say you are normally running too rich. The denser air is leaning your current AFR.

Did you get any AFR readings from any recent dyno's?

http://www.proficientperformance.com/tech_atmospheric-conditions.htm
 
#4 ·
TruBlu351 said:
As you've addressed, there are 2 issues at hand. Cold air is more dense and would normally require upsizing jets to keep your optimum AFR constant. So if you're saying that you're getting an extra ordinary hit on a cold night, then yes, you could say you are normally running too rich. The denser air is leaning your current AFR.

Did you get any AFR readings from any recent dyno's?

http://www.proficientperformance.com/tech_atmospheric-conditions.htm
Yeah thanks confirm what I thought. The extra ordinary hit seems that I am running too rich then for day time.

Fuel mixtures are all over the place as I'm swapping between BP100, Ultimate 98 and toluene depending on availability. All different densities requiring 1-3 jet changes on the extreme.

An on board exhaust gas analyser would be good, I'll try track one done.
 
#9 ·
STROKEXD said:
Did some research today tracked down a US kit for a few hundred $.

I'm off to Asia soon so I might pick up something there..
Which kit are you looking at in the US?

Ideally, although they cost more, the perfect AFR meter uses a wideband O2 sensor. They read 0-5v instead of the normal 0-1v.

Yep, rice burna central should have all sorts of gizmos going cheap. You'll just have to fight thru all the fluro light bulbs and wood grain gear knobs first!
 
#10 ·
Nordskog, here's the links:

http://www.nordskogperformance.net/products/auto/proanalog/page5.htm
http://www.nordskogperformance.net/products/sending/page2.htm

I think the O2 sensor is only 0-1V for US$87, but by way of comparison the Auto Meter one which is a wide band I believe, Go Gear in Oz PArk quoted me $300+ ouch.

Found a great Speed Shop in Langkowi a duty free island last year, bought an Alpine CD/MP3 player for AUD$400. Same unit here over $1000 so fingers crossed they have some good gear.
 
#11 ·
That Nordskog analog AFR gauge looks great (US$280 w/sender). LED bar graphs are OK, but I prefer ACTUAL readings on the gauge, especially when it comes to tuning and looking for exact ratios.

That new Autometer website is giving me the craps. Can't search or find their AFR meters. I'm sure they're 0-1V.

Type in "air fuel" on ebaymotors and look at the miriad of different types that come up.
 
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