Thanks Aaron. Looks like around 10* from ambient is about right. So for once my memory wasn’t completely bad.

In comparison the AIT with AIS ran around -1 to +2 degrees from ambient when up to speed. It would go to around +20* of ambient when sitting still. It hit 95* here today and I was seeing 94-96* while up to speed. Not much different than the 6637 which I believe others have proven before.

So this whole experiment is just that, an experiment. Sous had mentioned being curious if the AIS would keep up with the SXE during our phone conversation before I did the T4 swap. I really like the AIS so figured why not try it out and see. Really had no hope of it working well.

Today I did a 2 hour trip empty trailer and 1.5 trip loaded with a UTV. Obviously this is not much weight for the ole powerstroke but still a light towing test. The AIS was very quiet. I asked my wife if she thought it was quieter and got a confident yes. Again the 6637/SXE is quiet, but this is basically silent.
It actually performed well. I drove like I had some sense with probably did only around half throttle acceleration bursts when merging into traffic and such. The EGTs were in check at all times. Boost came on smooth and hit around 25psi max with my lighter foot. The FM was only pulled to the 1st click (25%) after the entire trip. I’d say under these conditions the AIS was functioning well.


Only at 25% after 3.5 hours of driving and some light towing with no full throttle runs. Saw around 25psi of boost.

I’m not delusional. I know the AIS will not provide all that I’m asking of the truck and the 6637 will be a better fit with the SXE. I’ll likely put my new Donaldson on tomorrow. But this was a fun experiment and I am impressed with the pairing of the AIS/SXE. If only it flowed a touch more. Any company want to make a drop in dry filter for the AIS box that will flow better but still clean the air?

So I think this trial has about come to its end..... Unless I message my friend and he says he’ll still buy it if I open the box to the fender. I still feel this will only slightly help but we’ve came so far already. Why not finish it out?

And now I’m wondering if I should have just started a completely new thread for this topic now that it’s coming to an end.

The thing that still puzzles me is the feeling that the truck is more light throttle responsive with the more restrictive AIS. At this point I’m anxious to get the 6637 back in to prove to myself that I’m crazy and they actually respond the same. The only explanation I can come up with is it may seem that way since it’s quieter.

 

My SXE is usually pretty quiet although I can always hear it- with the 6637. When towing 13,000 pounds plus up a steep hill I would not use the word quiet, it is pleasantly loud and I wonder when it will stop screaming an self destruct and fly apart, not that it will, but the sound is pretty wicked you can hear the pitch changing as it spins faster and faster and faster. I don’t mind the sound as it is usually only for a few miles and sounds cool. I don’t travel far, just the same local roads routinely.

 

I think now we should do a possible temporary swap and you try the s&b 2nd gen with filter minder drilled and placed in intake tube?

 

akcooper9

Never seen trans TC slippage PID showing minus values on mine.??

 

Maybe “quiet” isn’t the best word here. Sous and akcooper9 both told me not to worry about noise with the 6637/SXE. I’ve had the 6637 with both 38R and stock turbos and was not looking to go back to that sound. They were correct in the 6637 does not sound the same with the SXE as my previous experiences. The word quiet was probably me trying to relay to others the fact that it is not noisy and to keep them from having the same worries I did before using it with the SXE.

I do not feel like it screams, not even in the least. Even when doing my test tow recently it was relatively “quiet”. You could hear the turbo “sing” when under load but it was not excessive and as Sous has said many times I don’t feel like it is any louder than the MST with AIS. Maybe similar but with a different tone.

I hope to have a better word to describe the 6637/SXE now that I’ve have some real time with the AIS. Doing a check today while it’s fresh in my mind will help the comparison. As will going from the super quiet to less quiet.

I will say that yesterday during the light tow you could only hear turbo whistle when pulling a grade and even then it was muffled and faint. It was most definitely quieter than the 6637/SXE. I’d venture to say the AIS/SXE is the quietest 7.3 I’ve ever been heard. It’s nearly silent for intake/turbo. Took dad on a short trip yesterday and he was commenting on how quiet it was as well.

All in all the silent AIS/SXE combo isn’t worth it for the trade off in flow during hard pulls. At least that’s my take on it. I will be towing heavier and seeing 35psi at times. The 6637 didn’t even pull enough vacuum(restriction) to move the FM under sustained 35psi runs. The AIS would pull the FM all the way with one 35psi burst. From the looks of this test, 25psi seems to be about where the AIS begins to become a restriction. It pretty well corresponds with my experience with the MST/AIS as I could hit around 30psi and the FM would be around 50%.

So maybe this is the statement to sum this entire experiment up. An AIS is feasible to about 30psi.

Hmmmm. You may be onto something here. That would be an interesting addition to this test. And a good way for you to encourage the trade instead of me selling the AIS locally.
I’ll need to think about this a bit. Our toy purchase yesterday makes the thought of extra cash sound nice, but what you’re proposing is part of a test for the greater good of FTE.

If this is like other transmissions that I’m more familiar with then what you’re seeing is just due to variance in the sensors. This PID should be coming from the calculation of engine speed - transmission input shaft speed. In reality the number would be zero in lockup. But what you see is a result of sensor fluctuation during the moment in time when taking a snapshot of the readings.

 

FWIW, the noise with my 38R and AFe intake isn't too bad. I am a turbo whistle addict though.

 

Thanks for the input!

If you like the 38R sound then you may be disappointed in the SXE whistle....

Personally I don’t have any issues with the 6637/SXE sound but love the clean look of the AIS. Of course the noise reduction of the AIS is a bonus for me. I think I dislike the look of the factory battery cover more than anything when using the 6637. And if it’s removed it just doesn’t look right due to the battery box design.

What’s the extra ductwork? Cooling for the alternator?

 

[I will probably miss the turbo noises a little but my objective in switching to a T4/SXE setup is to rein my EGTs in. I'm willing to lose turbo whistle for that.

Yup!

 

I have the AFE as well and just finished my SXE install. There is still a whistle but it is not loud or obnoxious. Of you like the 38r then you will probably be disappointed in the lack of noise.

 

So this morning the AIS came out and the new Donaldson went in. Sorry guys the FM is not plumbed into this but we’ve already proven a used one will not even budge the FM under sustained 35psi pulls.

I took a little drive with the wife while taking the empty trailer back to it’s home. We knew very quickly that it was not as quiet as with the AIS. I know there’s no surprise in this. But to try and do it back to back and quantify was my goal...guess I should have taken more videos of the AIS. Oops.

Anyhow, you can definitely hear more sucking air noise and pronounced turbo with the 6637. Not obnoxious or overbearing. But it’s there. The whistle was most definitely louder, but it doesn’t bother me.

On the test drive the temps was staying around ambient while moving as we have already stated with akcooper9’s help. Mine was actually almost exactly the same today. When I stopped there was a bigger difference (as would be expected). AIT was about 40* over ambient at idle. Still not a big deal because our use is while moving.

The feel of more throttle response with the AIS was accurate but I think I’ve come up with the reason. I believe it’s just the sound. Since the AIS is so quiet it appears to be doing lots of work with no effort. The 6637 although not noisy does let you know you’ve moved the pedal.

Here’s the weird part. I swear it was smokier at tip in throttle around 55mph with the 6637. This goes against all logic but I swear this is the case. In the 65 tow yesterday (hotter yesterday by about 10*) it would barely haze when tipping in at that speed. With the 6637 it would noticeably smoke a bit then clean up. Checked it multiple times. Even with the UTV loaded up yesterday there was barely a haze with the AIS in the 65 tune. Now 80hp and the AIS did show smoke, but not the 65hp.

Someone explain this to me please.

After returning I also modified part of the upper air box and added to the mix. This is in an attempt to better direct the cool frontal air toward the filter. Otherwise I figure a good bit of the air just passes right by. And as a byproduct it should also shield a bit of the engine side heat. Don’t know if it will work but worth a try.




I'm being beckoned by the family so out of time for this post. I’ll try to come back later for more info.

 

I 2nd the haze with a lower tune and smokier with a hotter tune. I was noticing this today.

 

JT the strange thing about it in this case is the fact that I was seeing a haze with the AIS but some smoke with the 6637 while in the same tune. The more restrictive AIS should cause more smoke not less. I’m totally befuddled.

But yes I see smoke in anything more than the 65 tune. Which is probably normal. I rarely ran anything beyond the 65 with the MST but have been playing with a lot of things while testing out the SXE. At first I thought the SXE was smokier until I realized (thanks to another member) that I was playing with hotter tunes than I was used to using.

 

Just a theory - fueling is related to boost. If the 6637 is able to make boost faster maybe it allows more fuel to make the smoke??

If I decide this idea is really dumb after coffee starts working - I agree to wear a dunce cap for the rest of the day.

 

No sir that cap is all mine!

I’m just glad to hear someone come up with a theory. I don’t think that’s it myself but still glad to have you throw some ideas out there.

The AIS and 6637 seemed to boost about the same during “normal” driving. Cruising at 60mph both appear to be around 2-2.5psi. (Boy it’s hard to get steady state readings). At a part throttle burst both would go up to around 25psi in the normal SXE smooth application. I wish I had thought to take some video while towing with the AIS. We were preoccupied with our purchase and pickup.

My only theory is somehow the slight restriction is helping the turbo to “work” better when it’s not being pushed to its limit. Kind of like gas engines needing a bit of backpressure on the exhaust side. (My headers are big for my little 289 engine so exhaust extensions picked me up 0.06 seconds of ET) No I can’t explain the logic of it as I would expect a turbo to want free flowing air to the inlet.

If the smoke thing is true then it actually supports my stance that it “feels” more responsive at light throttle.

Who knows I may put the AIS back on later to check again. My battery terminals aren’t liking all these on/off cycles though.

All I have for direct comparison videos is a 140hp hit on both setups. But the speed range is different. I may upload them to YouTube so you all can hear the difference and see the EGT is actually very similar. Unfortunately my camera skills did not get the boost gauge with the 6637. I’m thinking Noob needs to stop by with his 4 camera setup so we can catch all angles.

 

I think it’s also a possibility that the FM (knowingly a rudimentary method to check this) might be getting pulled only during the quick drawl when first trying to boost hard. What I’m saying is the initial suction may be higher than sustained.

But I do know the 140hp pull was down by about 2psi with the AIS which tells me it’s wanting more air under those conditions. Now the thing is, I don’t typically run at those conditions and don’t really care about how it functions with the extreme tune.

The correct way to perform this experiment would be to use the vacuum gauge Noob mentioned earlier so we could see what is actually happening in there...... wonder if I can get one for cheap just for giggles? I have a CCV hole that’s not being used right now other than to hold a plug.....