Sgtblue

iTrader: (16)

Some here have mentioned that they have relocated the IAT farther up-stream from the UIM, away from heat-soak issues. Doing a search in titles I wasn't able to find alot of information on exactly where it should be moved to. Currently I still have the stock elbow, but if there is a gain to be made by getting a GREDDY elbow to put the IAT in, I'm willing. Another option would be to buy the hard IC pipes and place it there, just after the IC.
Also a second question. If I do relocate using a new IAT, can I just diisconnect the old IAT and leave it, or do I still need to pull the UIM and plug it up?
Sorry if this is old territory for some of you. But I'd appreciate any opinions, suggestions, or a how-to link that I might have missed.

rynberg

I was already looking up some of Chuck's posts....

https://www.rx7club.com/showthread.p...ght=air+intake

Here's a nice debate I inadvertently started: https://www.rx7club.com/showthread.p...ght=air+intake

https://www.rx7club.com/showthread.p...ght=air+intake

tom94RX-7

iTrader: (5)

go to the link below to see pictures and more info about my iat sensor location - FMIC outlet.



https://www.rx7club.com/3rd-generation-specific-1993-2002-16/greddy-2row-fmic-airinx-intake-install-pictures-454605/


I had it in the stock elbow for a short time before its new location, it was a little better location in the stock elbow compared to the stock location under the uim, but the ic outlet location is so much better than the elbow location! The ic pipe (where the iat sensor is located) only gets a little warm at the most from heat soak because the top of the pipe extends to above the radiator, so for the most part heat soak is not a problem.

You can move it to either new location for a improvement, but if you have the stock intercooler, there probably would be no difference when having the iat in the hard pipe coming from the stock IC or in the elbow, this is because those hard pipes going to the elbow get very very hot just like the elbow does. My ic pipe connecting to the greddy elbow gets just as hot as the elbow does because it is above the radiator, but the ic pipe connecting to the FMIC is so much colder at the connection of the fmic.

You would be better off putting the iat sensor in the stock elbow if you have the stock IC, I think it doesn't get as hot as all the metal pipes and elbows get. I mounted my iat sensor in the stock elbow exactly as I later did in the fmic pipe as seen in my pictures.

You will need to use the stock wiring going to the stock iat sensor, you should just use the stock iat sensor and extend the wiring to the stock elbow, then you would have to remove the uim and plug the hole with a bolt that fits, you may have trouble finding a bolt that fits, the thread is not a common size, I had to get a bolt for it at the local advance auto parts because the hardware stores didn't have the correct bolt, and I had to cut the bolt I got because it was too long. If you really wanted to you could get a new stock iat sensor, leave the old one in the uim, and use the stock wiring and extend it to connect to the new iat sensor.

Sgtblue

iTrader: (16)

Thanks to both for the replies and links. I've already got a new IAT and will probably be relocating to the stock elbow...for now. I've just got to decide about placement to keep it out of the way as much as possible.

Mahjik

iTrader: (1)

I would recommend only doing this with a programmable aftermarket ECU. It's unclear if the stock ECU has compensation for possible slightly higher readings that might occur in the stock location.

However:
https://www.rx7club.com/showpost.php...2&postcount=14

https://www.rx7club.com/showpost.php...6&postcount=15

twokrx7

iTrader: (1)

Mahjik, the car will run richer with this mod so it should be safe even without a programable ecu.

Biggest detractor of the stock location is heatsoak which makes the car run lean after a warm startup, until the sensor cools.

Mahjik

iTrader: (1)

Richer is NOT better.

Too much fuel can/will wash away the oil lubricating the seals.

I did this mod on my car (using the Pettit ECU) last year. I did also lose my motor last year. While I don't know if this mod had a play in the motor going, it will be going back to the stock location when the motor goes back in.

tom94RX-7

iTrader: (5)

Relocating the sensor to a stock ic pipe in a car still using the stock ic will not make a difference compared to the stock intake elbow location because those ic pipes get just as hot as the elbow and just about just as hot as the UIM, because everything up around the engine gets soo hot. But if you have a fmic, the pipe connecting to the fmic outlet stays cool where it connects to the fmic outlet (the fmic outlet is always cold and the pipe gets just a little warmer at the connection, but never close to hot), so if you put the sensor there next to the fmic outlet, you basically get no heat soak.


I did the same and did notice a very small difference just like most people who do this, temps didn't get as high, but the difference was nothing compared to how much cooler the temps are when the sensor is in the fmic outlet.

tom94RX-7

iTrader: (5)

This was probably my main reason for doing this to hopefully cause the car to run a little richer to be alittle safer since I haven't had my afr's checked after getting the PFC. For me the temps (stock sensor location) would practically never cool down below about 60C after they got that hot or hotter, they get that hot from driving for a little while in the summer, not just from a warm startup, the sensor really never gets cooled off especially if you have the stock intercooler.

Any idea how much "too much fuel" is? I also added some extra fuel to my PFC inj map, do you think maybe I could be running too rich?

Does anyone know how much richer the car runs when the iat temps say on the commander around 20-30 compared to about 50-60 like they did with the iat sensor in the stock location ? thanks

rynberg

Assuming default PFC settings, 2.8% more fuel is injected at 30C IAT vs 50C IAT.

Sgtblue

iTrader: (16)

Damn. You guys are so far ahead of me. Just when I think something is straight forward... like moving the IAT to a relatively cool plastic compression tube vs. hot cast aluminum UIM. I am still running on the stock ECU. Although Mahjik's caution is noted, I'm still leaning toward relocation but appreciate the input.

Mahjik

iTrader: (1)

Tom,

If you have a programmable ECU, program it to what you want. Don't trick it do something it "might" or "might not" do. That's kind of the whole point of having a programmable ECU.

twokrx7

iTrader: (1)

Guys, when we talk richer we're not talking about flooding the car with liquid fuel. Many here run in the 10's on AFR. Now when it comes to carbon buildup, watch out. My Pettit ECU car ran so rich with so much carbon buildup that the apex seals got bound up in the grooves, they no longer sprung out to touch the rotor housings. Killed my compression, after many miles that is, still made mad power when warmed up tho.

Mahjik

iTrader: (1)

That's basically my point. You are potentially introducing a much richer condition that already exists. The stock ECU runs in the 10's for AFR. I'm sure most of the other rechipped ECU's are plenty rich as well which is why I suggest NOT doing this modification unless you have a programmable ECU.

It's also unclear (or un-researched) whether the stock ECU conpensates for possible heat soak of the sensor. For these reasons, IMO, it's best to leave it "as is" until a programmable ECU is used.

However, this is my opinion. People can make up their minds what they want to do with their own cars.

Sgtblue

iTrader: (16)

Mahjik,
Any idea how much richer (if any) the Petitt ECU is over stock?

Mahjik

iTrader: (1)

Unfortunately, I have no idea. Someone did get some AFR's of the Pettit ECU while on a dyno (stock ported engine IIRC):

https://www.rx7club.com/time-slips-dyno-121/dynoed-my-car-today-259617/