it's just a six
Member
- Joined
- Dec 27, 2005
- Messages
- 537
By registering with us, you'll be able to discuss, share and private message with other members of our community.
SignUp Now!Phil,
IAT is only an issue when the chip makes a tuning decision based on its readings. Aside from that, no issues.
The weight of the CO2 kit is offset by any performance gain.![]()
Why?TT SD chip uses IAT and Eric recommends location in plenum or up pipe but make sure it is mounted before any alcohol nozzle.
Will get it moved this week.
Julio: In a previous post you said "Phil, IAT is only an issue when the chip makes a tuning decision based on its readings. Aside from that, no issues".
So I go back to TT website and Steve Wood advised me to follow Eric's recommendation so I went back to the SD Chip Instructions and this is what I read: "The chip uses manifold air temperature for fuel corrections. You should move the factory air temp sensor to somewhere after the intercooler. You can mount it in the plenum or in the up-pipe. Just make sure it is mounted before any alcohol nozzle."
After reading that I felt like I should move the IAT to a position after the intercooler but before the alky nozzles.
Then I get this question from you "Why? If iat is let's say 70 degrees going into the combustion chamber then why would you not want timing/fueling be adjusted based on that temp?" I read this comment that I should move the IAT but to the plenum which is after the nozzles.
I want to make the right decision in this matter but I feel I have conflicting solutions from reliable and knowledgeable people. Please help me out, I have a date with a Ford in Noble on the 16th.
Thanks.
Phil Engle
Your up-pipe temp will always be higher than outside.
Understand a turbo heats air. Typically its 11 degree's per PSI. So at 20 PSI its 220 above ambient going in. So if its 80 degree's and you run 20 PSI=300 degree's going into the IC.
Now what comes out of the IC.. thats the impossible question to answer given so many different IC, air flow through it, core, etc.. Lets say its 130..
The alcohol will chill that down to 80..
The wideband will make air fuel changes irreguardless of 80 or 130 going into the motor. As its looking for "air fuel". So it doesnt care whether its 80 or 130 going in.
The main issue is for SD tuning the IAT sensor calibrates fueling based on temperature.. but a lot of aftermarket systems disable any enrichment after the motor goes into boost. This also brings the question of really reading proper IAT. My engine see's 140-160 degree's IAT temp in stop and go traffic. If the sensor was placed pre-tb.. it would be way lower. On this same line of thought, most OEM's place the IAT(Intake air temp) inside the intake..or MAT(manifold air temp). So this brings up the question again.. why do it in the up-pipe?
Again this would be an issue for Eric or Bob to answer as the majority of "chip" cars use their products.
Am I off?![]()
"If the air was just simply getting colder, then I would say, yes, put the sensor in the plenum. But it's not just getting colder when the alky is spraying, it is also getting much richer, since alcohol is also a fuel. So, its adding its own enrichment. If we put the IAT sensor after the nozzle, the chip would add even more enrichment, which would end up being too much.
In the end, if it's running in closed loop, it would pull the fuel back out anyway, but it may be jerking the A/F all over the place."
Is there a place in the plenum that is a preferred location?
I think both positions have their merits but the proverbial proof is in the pudding so what I'd like to know is where the the IAT is placed by tuners who are not using XFI but a stock ECM. Bison, Grumpy and Otto would be good examples along with the members of your quickest time list who do not use XFI.
I'll email Bob and the 3 names I mentioned and see if they will comment on this subject.
Phil Engle