legacycentral bbs

As you all know, I'm working on my new engine and will be running speed density instead of MAF. I'm getting to a point where I need to get something done on my intake so I can get it off for coating. (There's a guy local who can do the ceramic coating and I figure it'll only cost me another $40 over just painting the intake so... why not).

I'm trying to decide if I should mount the sensor in the center on the radiused section or if I will still get a good accurate reading if I mount the sensor on one of the flat portions near the front of the plenum. The position near the front is less centered in the direct flow after the TB but it seems like it would still get a good reading going into the cylinder. I figure I would will have better chances at good sealing in the flat but will I still get an accurate reading?

Does anyone have any experience with any of this? Any general thoughts? Any help or advice would be greatly appreciated.

Thank you.

I think IAT's are supposed to be Pre-TB. The one on my 98' was mounted about 3-4 inches in front of the TB in the IC piping.

Just after the TB would be best and provide the best option for not getting heat soaked. That's where I have mine installed.

http://www.main.experiencetherave.com/s ... P_8829.JPG

this is for intake air temperature sensor correct?

Grayguy wrote:I think IAT's are supposed to be Pre-TB. The one on my 98' was mounted about 3-4 inches in front of the TB in the IC piping.

I agree, that's the best way by far. Placing it in the manifold will make it harder to get a temp reading of the actual air entering the motor, as the temp of the manifold itself will skew the readings.

Well, your a little late to game here .

I've already placed the sensor in the manifold. I have it placed where it will catch the air just after the throttle plate. I didn't want to place it pre throttle plate because I'm running a water/meth injection and want to make sure I'm getting an accurate reading of the air just before it enters the cylinders. I've ceramic coated the manifold itself and my coolant cross-over pipe is also ceramic coated, and I'm running phenolic spacers. So I figure I'm reducing heat soak as much as possible and should be okay.

Picture of placement -

wow lee, I am loving the progress. I cant wait to see that thing in action at auto x!

Matt, , I can't wait to get out to Auto-x. I was on schedule for this month until I ran into issues with my water injection pump. Now I'm being pushed out until July (but I keep kicking around the idea of racing my Outback...).

Engine bay is all done (water inject pump aside) and I just need to finish wiring inside the cabin and then tune. I have a teaser pic (cheap cell phone picture) of the completed engine bay in the pictures forum.

You're gonna like it when you see it in person. It's taking me a lot longer than planned but it's being done right and is looking sharp .

I'm curious as to what the water/methanol hitting the sensor will do to the readings.


What are you tuning with, and are you trying to do it in one map?

Dan,

I'm curious about the water injection as well. I'm injecting at the middle of the bend in my turbo-to-manifold pipe seen below. The little red line is the water feed line to the injector.

For tuning, I'm using Derek's old MAFT-Pro. My setup is actually almost mirroring his - Zeitronics MAP sensor, his old injectors and his old FPR. I know others on the MAFT-Pro forums use water injection on speed density setups. I don't see how you'd accurately control things with the IAT before the water injection on a speed density system since you're measuring pressure within the manifold and would be measuring temp prior the throttle plate. The injection is a pretty fine mist and I'm curious to see how quickly it evaps before it hits the probe.

With the MAFT-Pro's ability to do closed loop fueling control at WOT I'm assuming it will be able to account for any slight variations in intake temps due to potential water on the sensor. Or atleast that's the thought. I should have it running by next weekend to see how this will actually work out.

How does this sound to you?

Sounds like you've thought it out fairly well.


My only suggestion is adding a bung before the injection point to compare. More data is always good. If your current location works out, then more power to you. If it doesn't, then at least you had the option to find out. You can always plug one of the bungs, or weld it shut.


It's cool to see his old setup put to good use. It was very capable, and I'm disappointed it hasn't caught on in this crowd. The fuel and boost control is top notch, and hard to argue for the price, as long as one is willing to invest in a wideband.

Sexy engine bay! Any ideas what u will be putting down for power? How much boost do you plan on pushing. I would like to see what that set-up is capable for. Still bummed I had to sell it, but at least now its potential will be unleashed!

What is that other sensor on the front of the manifold with the red and green wires?

Dan, I have an extra IAT that I do plan on putting just after the turbo. It hasn't happened yet and I've got to calibrate the IAT from the MAFT-Pro to the Zeitronix's but later this year I will actually be doing some data logging on how effective the water injection really is at cooling. And I'm also very excited to try this EM. It seems to hold a lot of potential and I know both you and Derek have spoken highly of it. I'm personally hoping Derek's old tune is still on it, would make things a lot easier to get moving .

Matt, thank you for the compliment. It looks even better in person . I'm shooting for a top goal of only around 300chp. But I'm anticipating a large power band so it should be a great daily driver and tear it up at Auto-x with the quick spool. For the time being I'm only running wastegate boost until I get the EM nice and sorted out where I want it. Then I'll start turning it up. Though the wastegate still seems to be around 15psi so it should have plenty of kick out the box.

Maciek, that other sensor is my MAP sensor. It's a 3.5 bar sensor from Zeitronix's. The EJ20H manifold has a nice threaded spot there that made it really easy to mount my MAP sensor. As long as it doesn't fatigue and break I should be good. It makes a convient spot to measure the plenum directly without getting into the pressure waves found in the runners.


These last bits are still taking a lot longer than I anticipated so I might not get it turned over until during the week. Hopefully I don't end up with a car that get's rolled on by Geo's - but if I do, at least it'll look good .

Seems to me it's all up to where the person tuning the car is most comfterble having it (the IAT sensor). Phil the owner of Element Tuning told my buddy to put it just before the turbo in the intake even though he himself admits that it should be closer to the throttle body. But due to the fact its eaiser to install it pre-turbo and he's used to tuning the Hydra with it in this position this is where he wanted it.

It really depends on the engine management and whether it's MAP/MAF based, and what sort of correction factors are setup in the EM. MAP based systems, you really need to have the temp of the air entering the engine, ie. post turbo and intercooled (if any). Can you compensate without....probably, but there may be other undesired affects.