it's just a six
Member
- Joined
- Dec 27, 2005
spray on intercooler
- Thread starter williambavila
- Start date
TURBOPOWERED68
David
- Joined
- Jan 31, 2006
any body want to donate an IAT sensor i'll install it on my up pipe then i'll put a toggle switch and switch from up pipe to before MAS and let you guys know what i find
The easy way to answer that question is to look at the signatures of the thousands of users here. There's only a couple of names that keep "popping" up, and that isn't one of them. Primarily look at the ones that tickle the 9's and drive'm to work.
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.
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.
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?
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
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
Generally speaking, most EFI systems reference the intake air temperature sensor for marginal to moderate fuel corrections based on swings of air temperature readings in the manifold. An increase in air temp of say 60* (from 70*F to 130*F for example) can be a change of up to 5 or 6% across the board in fuel reduction. It might not have a giant effect in the vacuum ranges, but under boost a change of 5% is significant when trying to maintain a strict air/fuel ratio.
This statement looks backwards to me. The intake air temperature sensor needs to be post alcohol nozzles at least to the point where the alcohol flashes and performs its change of state into a gas, "activating" its high latent heat of vapourization and dropping the temperature of the charge significantly. The high drop in air temps needs to be recognized by the EFI system in my opinion to account for the now denser charge unless the chip (in the system you guys use) is programmed for a specific amount of alcohol and disregards the intake air temp in boost. No matter how it's done, the end goal is to achieve/maintain a given air/fuel ratio when the alcohol is introduced into the system.
My opinion is to move it after the alcohol injection point unless there's something specific to this chip and the system you guys use when using Julio's system in conjunction.
B
I'm with Brian on this.
My own car has the IAT inside the intake manifold. I do it becuase I like to log my IAT data inside my motor.
But I am not the one making the chip on your car and have no say in how its tuned. Thats a personal issue between you and your tuner.. in this case chip maker.
There is an old saying.. there are many ways to filet a fish.. its up to your own decisions as to how you want to do what. Same goes with timing, air fuel targets, types of spark plugs used, type of head gasket used, engine clearances, etc etc etc.
Not saying one way is wrong or right, thats on you :redface:
My own car has the IAT inside the intake manifold. I do it becuase I like to log my IAT data inside my motor.
But I am not the one making the chip on your car and have no say in how its tuned. Thats a personal issue between you and your tuner.. in this case chip maker.
There is an old saying.. there are many ways to filet a fish.. its up to your own decisions as to how you want to do what. Same goes with timing, air fuel targets, types of spark plugs used, type of head gasket used, engine clearances, etc etc etc.
Not saying one way is wrong or right, thats on you :redface:
jasjamz
THS Racer
- Joined
- Sep 30, 2004
I placed mine where the Turbo Tweaked advised and it stays very very close to the target A/F. I have a dual nozzle kit on it too. It still makes adjustments using the w/b but I know the IAT temp difference between the air filter location and the uppipe pre alky can differ in upwards of 50*. My IAT at the trap with 29 psi was 130*. This was on a day with temps in the mid 70's.
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?
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?
jasjamz
THS Racer
- Joined
- Sep 30, 2004
I understand and agree with you on all the but what i was trying to point out was that if you compare the intake air temp reading at the stock location vs the uppipe pre alky for the sd chip you will see the difference. If you turn off the wideband tracking the iat is your only assistance now. Why would one place it in an improper location. That would add to tuning issues. I agree. We should do what the chip makers decide because they have tried it many ways and point us in the best direction for their product.
The stock air filter location was used when the car was MAF.
Once you go SD.. the sensor has to be moved.
This up-pipe IAT started back in 2002/2003 when the MaxEffort stuff was floating around.. as it was the first pseudo SD stuff with the thumbwheel.
My point, Buicks are the only ones putting the sensors in the up-pipe for tuning as far as an OEM application that is turbocharged. And I fear the alky issue was probably more in the lines of fear it would mess up the sensor not relation to what would work best. So once a trend started.. it kept going.. Maybe it was done so no holes would have to be drilled into the intake or doghouse?
Whatever floats the boat :smile:
Once you go SD.. the sensor has to be moved.
This up-pipe IAT started back in 2002/2003 when the MaxEffort stuff was floating around.. as it was the first pseudo SD stuff with the thumbwheel.
My point, Buicks are the only ones putting the sensors in the up-pipe for tuning as far as an OEM application that is turbocharged. And I fear the alky issue was probably more in the lines of fear it would mess up the sensor not relation to what would work best. So once a trend started.. it kept going.. Maybe it was done so no holes would have to be drilled into the intake or doghouse?
Whatever floats the boat :smile:
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?
No, you're not.
When I read the TT SD instructions, I started looking for a bung to put into the up pipe and when I was calling the local performance and turbo shops, they asked me why I was putting it in the up pipe and not the plenum. I even called a fellow club member to see where Jack Cotton placed the IAT which is in the plenum but that is with an XFI.
Here is Eric's reasoning behind his recommendation.
"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."
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
a couple quick notes.
all the different mounting schemes have advantages and disadvantages, which can all be 'tuned around'. It depends on your tuning style and needs.
The up mounted IATs typically result in the best day to day driveability on a speed density car in my experience, as the fueling changes controlled by the IAT track the air density entering the cylinder fairly closely.
At WOT, if you put the IAT after the alky nozzle, then the chip adds extra enrichment due to the cooling effect of the alky. You can tune around this, so its not a huge deal. But for us purists, its not what the chip/translator software is expecting.
Bob
all the different mounting schemes have advantages and disadvantages, which can all be 'tuned around'. It depends on your tuning style and needs.
The up mounted IATs typically result in the best day to day driveability on a speed density car in my experience, as the fueling changes controlled by the IAT track the air density entering the cylinder fairly closely.
At WOT, if you put the IAT after the alky nozzle, then the chip adds extra enrichment due to the cooling effect of the alky. You can tune around this, so its not a huge deal. But for us purists, its not what the chip/translator software is expecting.
Bob
" it is also getting much richer, since alcohol is also a fuel" this statement is true whether the sensor is in either location.
Yes the air temp drops and it adds fuel.. great. The alcohol is a fuel.. great. Then its a matter of balancing how much fuel the chip delivers to "dial in" the air fuel.
If the up-pipe is insulated from heat, it is possible to have a 20-30 degree difference between readings post and pre turbo. Example stop and go traffic with the AC "ON".. the IAT will continue climbing as the intake gets hotter and hotter. This temp inside the intake is the temp going into the combustion chamber when the intake valve opens.
On my stock computer app.. I had my IAT sensor in the intake. I never had any issues. What I liked was being able to datalog those temps when racing the motor. This would be data not available had the sensor been pre-nozzle.
I like the location in the intake below the rear upper plenum bolt boss.. the sensor is mounted under the oil pack bracket. But this requires the intake to be off the vehicle for its mounting.
The place most use is on the passenger side of the upper plenum, that way the intake does not have to be pulled for its installation.
I have also seen it on the drivers side rear bottom section of the upper plenum. In between the TV and throttle cable. It hides a little better.
All locations inside the intake function the same.
We run an reg old Turbo Tweak chip. NOT the SD one. We try an keep things simple. Simple is a lot easier for old people who's brain fades a LOT
