OEM airbox swap?

[454cid]

Got it in.... faster than I thought. I didn't disconnect anything except the vacuum line I won't be using anymore, and the coil wire since I have it tucked into molded plastic hooks cast into the lid. I did not replace the filter, as it still was decent looking. I've read that the heat door being open can do that, and mine was partially open.

I also filled up with gas today, so most of this tank will be with the Turbo lower box. It would be great if it got me just a bit better mileage.

[kallekula]

I glued it shut after realizing it was only pulling hot air. No $hit car started running much smoother and got better mpg too.

[454cid]

I glued it shut after realizing it was only pulling hot air. No $hit car started running much smoother and got better mpg too.

I had my doubts when you said your car ran smoother, as my car was pretty smooth any way, but somehow it does actually seem smoother. I don't know if it's the power of suggestion or if it really is smoother. I sure have been enjoying it, Though. I think I'm getting low enough on gas now, that I'll fill up tonight after work, and will check mileage. I did start watching fuel trims yesterday, and LTFT has dropped from a steady 3% down to very close to zero. It was bouncing between 0 and .03%, so that's certainly looking good!

[kallekula]

The air temp i measured was around 160F, so yeah that is way high. Why do you have doubts about what I write? Do you think i just make shit up and post here?

[454cid]

The air temp i measured was around 160F, so yeah that is way high. Why do you have doubts about what I write? Do you think i just make shit up and post here?

Hmm, I didn't think I was being offensive, so let me clarify.... I wasn't expecting the modification to yield the same effects on my car, as you experienced on your car. Firstly, my car has already been pretty smooth, and also because my hose to the manifold has already been removed (so warmed, but not hot air), and I have no idea what other differences between cars there might be.

It definitely wasn't my intent to be offensive, and I apologize for that.

How did you measure the air temp in the filter box? I find it odd that my car has no IAT, but apparently that's normal.

[kallekula]

Read through what you write before you post it.

[454cid]

Well, disappointment when I filled up. My mileage is actually lower. I did make a trip across town Sunday, so hopefully it's the few added local miles that did it. I've also had some stop and go through construction, although I had that last fill up too.

[scot850]

On an NA the pre-heat pipe is more for cold weather starts and in cold areas like up north here. At -30C you ideally need that. In fact on a turbo it would be nice to have to stop the intercoolers freezing!

The issue is that the thermostat fails and I can't recall now if you can even replace it or had to replace the whole box. I may have read you could use the one from a 240 and make it fit.

The problem is when the flap jams open then you get too hot an air charge which plays with the charge temp. Cooler air gives better power.

The thermostat is ambient air temp controlled so can be open slightly on starting.

If I lived in a southern state, not having that flap is probably no loss.

Neil.

[454cid]

On an NA the pre-heat pipe is more for cold weather starts and in cold areas like up north here. At -30C you ideally need that.

Oh, I thought it was more for keeping the throttle body from freezing, or are they heated by coolant? They're buried on these cars, so I haven't closely looked at all the lines running to it.

The issue is that the thermostat fails and I can't recall now if you can even replace it or had to replace the whole box. I may have read you could use the one from a 240 and make it fit.

It seems that there are two styles. I found some sort of thermal actuator thing online. IPD, I think. Mine is different, Though. The flap is vacuum operated, but the vacuum runs though a temperature controlled valve that is mounted in the air box lid.

The problem is when the flap jams open then you get too hot an air charge which plays with the charge temp. Cooler air gives better power.

The thermostat is ambient air temp controlled so can be open slightly on starting.

Mine sits partially open to both sides. I don't think it functions at all, although I can move the vacuum diaphragm by hand. When I bought the car, it had one broken vacuum line at the aitbox. It's possible I didn't reconnect it correctly, as I didn't study it's operation, Thoroughly.

If I lived in a southern state, not having that flap is probably no loss.

Hopefully, I'll be putting the car away for the winter shortly. When I bought it, I intended to drive it year round, but after having discovered how rust free it it, I don't want to ruin it by driving it through the salt.

[scot850]

My car gets wrapped up for our winters up here. That time is coming very soon!

The warm up system was to help lower emissions when cold and help with throttle freezing.

Neil.