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DIY Intake. So far feels promising...

5K views 37 replies 10 participants last post by  Article_Automotives 
#1 · (Edited)
I've hated the stock intake every since I saw it. It just has to be restrictive and with miles of plastic duct, that kinks, morphs in different shapes and sucks from a small opening above the radiator, it cant be good, esp if you're gonna try to push past stock hp levels. When I built my intake for my Audi, I never really felt a difference when I was piecing it together. It was fast that's for sure but I never noticed what a difference it made until I traded it in. I put in the stock intake and it felt super super laggy and slow. Crazy

So when I started throwing codes from the Jb4 and probably my failing Diverter valves (turbo performance codes), I kept thinking the stock intake is probably hurting. Most of the times when it threw those codes, it took forever for it build boost. I built a cheap intake for my Audi how hard could it be for the quad? Well this may look simple but trust me it took a bit of time to figure out what would fit where and where would be the best place to keep the heat out, etc...

But this is what I came up with. Two 3", 90 deg, Aluminum tube (Bought from Amazon), a 2 K&N filters, some hose clamps (These tool-less ones are the best) and some sheet foam.


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Ok, so gets down with it. Yes, it feels much faster and dang, the lag has been cut in half. I've been driving it all after noon (Getting JB4 logs and taking the family to dinner, watching the IATs, etc). And just once it felt soft but the other times, I was feeling quite impressed. Before, I felt the longer I drive the quad the slower it feels. I'll try to get draggy runs next weekend and I'm thinking there will be something to show... stay tuned.

The notes: The big one, its louder but just a bit. Kinda disappointing. Driving normally, you might not notice. A bit more faint whistle at low rpms but no wooshes, blow off valve farts, just.. well, all I hear is my wonderful Ragazzon exhaust once it goes.

IATs seem a bit warmer when on it. I'm seeing around 5 degs above ambient. During stop and go traffic, it gets to about 10 - 20 degs over which is what I saw with stock but it can't be as good as stock at keeping the heat out. When I came home from driving, I felt the intake and it was ice cold and the engine bay was hot.. so if you're moving its not too bad?

I don't think I can get the stock clamps back on the turbo inlets. I've been taking the stock air box in and out since I got the quad and those clamps are easy peasy. But those lower ones.. dang.

I found oil in my drivers side turbo inlet. No biggie, you can see the EGR and PCV right there but my passenger side was dry as a bone.. =(

Here's the one that stumps me. I capped the high pressure venturi a few months ago. Figured its just a boost leak (I felt no difference). No codes. Then when I just left the carbon canister hose just hanging in the engine bay when I did my first test drive, no cel again. Wow. So i just left it disconnected for now but I may put a rubber tube back to my inake for it.

So hoping for the best and your results may vary (my car is mildly tuned. Discuss...

(and if anyone copies my intake, we all know who think he did it first!!)
 
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#2 ·
Stock intake for reference. The inlets right after the radiator (square accordion tubes) are way smaller than my 3" intake tube. I think the turbo inlet pipes are over sized and should flow good. The stock air filter seems way under sized for 500+ Hp. My air box is super hot after driving, its sitting right above it and the turbo inlet pipes run right above the hot turbos.

You can see the high pressure venturi and the Carbon canister tubes sticking out of the turbo inlet pipes.



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#8 · (Edited)
More so than finding the weakest link, it's more about freeing up the turbo so it can respond faster and gain hp thru out the rev range. Finding a bottle neck only frees up high end hp. On my much talked about old Audi, it used the same air box as its higher performing sibling, the S4. The difference in performance on my car was big. Maybe the results may not agree and it might not make a difference but so far, I can say that seat of the pants is good.. Real good.

For the $300 I spent on the intake I can say that the only down side is that it rubs my hood liner slightly and like I mentioned, I don't know if I can get the lower stock clamps back on... which might be bad, but if there is no performance gains, it will come back off..(It def doesn't improve the looks of the engine bay.. =(

And I think the reason the airbox sits so far back is that its the only place they had room in the Giulia Quad..

Also, what feeds the stock intake feeds my intake. There are two holes right above where the radiator sits to feed non heated air from the front of the car. I wanted to stay out of the air coming off the radiator that heads out thru those vents. I was also hoping to not block any of that hot air. The engine bay of the quad gets really hot.
 
#12 ·
I've been thinking of doing this ever since I removed the intake I made last year, I'm getting to it later this month since temps are more palatable in Chicago. My biggest concern has been those venturi valves, do you have any pictures of your current "solution"? Thanks,

I'm happy to see someone else thought the same thing I had in mind!
 
#13 ·
The only IAT info is what I posted at the top but in a nut shell it is slightly warmer but I think I'm still not activating the water cooled intercoolers. I believe they activate over 80 degs. I have no flow data but it should flow way more than stock.

The Venturi's... I had written two paragraphs about them on my first version of the originial post but figured no one probably knows what I'm talking about or cares so I took it down. But to answer your question, nothing. I had the venturi's deleted in an effort to get the the stock intake to flow more (Less high pressure leakage) and help with my boost performance CEL codes but I threw no codes or had any issues. So when I did my intake, I just pulled the carbon canisters and went for a drive and again, no codes or anything. I always thought they put a pressure sensor in that system to see if it was working but I guess not. If the new intake gets me better draggy numbers, I will run a hose to the carbon canister to the intake.

I was thinking about my intake last night and I have never been excited about a performance mod before. Even with the Jb4, I didn't want to post till I had some draggy numbers as it was a mixed bag of feelings. Kinda felt faster but it also started feeling slower the more I drove it. Last night when I was pulling in, I kept thinking "damn this thing is fast". I think changing my exhaust just put back in some HP i lost with my custom x pipe.

So I checked my Jb4 logs and saw something kind of interesting. I always had this weird drop at redline. Then I saw on the new jb4 log it was gone and the redline angle looks steeper and sharper (Meaning it was pulling hard). The first graph is from last year (after exhaust) and the 2nd on is from last night. The green line is RPM and ignore how I short shifted from 1st in the 2nd one and how 3rd gear didn't drop as much in the first. They increased the sampling rate and the damn car shifted out of first early on the 2nd one. Lastly,I noticed that the blue line (Boost) is dropping the whole time in 2nd and 3rd in the first graph but it looks line and rounded (It should look rounded, I'm adding less boost at redline with the JB4) in the 2nd one. I think the damn stock intake can't flow at redline (and it looks like it can't).

Stay tuned to this channel. If it doesn't make a difference, I'm here for you guys and not to sell my ghetto intake so I'll post the results...



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#15 ·
Fair question. Two reasons, one, there isn't enough room there to put the cone filters I have and two, it puts the filters right in the hot air coming off the radiator and out the hood vents.

The two holes that feed cold air to those ducts is still open right in front of where my filters are. I wanted to cut those ducts and maybe place the filters to the side but I still need my stock air box for visits to the dealer and what not.
 
#19 ·
There is zero chance of sucking in water. The cone filters are fed from the same holes that feed the stock intake and water (not drops) would have to pour in before it would be a problem. If water got that high, the stock system would suck it in like a straw vs an open cone filter. If the cone filters were exposed directly to the rain, then yes, that would not be good.

Also a few drops of water down the intake would actually help with IAT's. There are guys that spray water down the intake to help cool the charge (But wet filters are bad for flow).
 
#22 ·
#26 ·
Update.. I did get a few draggy runs in today and got mixed results. I did a very quick run down a sketchy street and I blew the start big time. Still ran a respectable 12.1 but at 115 mph, which was a great first result (115 was the very best I could run stock with my stock wheels, more on this).

So then I went to a long street near a beach, expecting great results but pretty much got the same. Sucks. The only good news was that I never got below 113 mph and ran another one at 115. That is the best mph I've run with my wheels. 1/4 mile times were not good (~12.2) but I noticed that I am about .2 (point two) seconds off my 60 ft times. The street that we usually run on has proven to be faster by about, you guessed it, about .2 seconds and given me a 1 to 2 mph boost.

Here's the breakdown from our favorite street:

Very best stock (*) 11.8 @115 mph
(*) stock was all over the place, I ran exactly one good 11.8 and kept it..

Stock with wheels: 12.1 @112 mph (I think)

Jb4: 11.8 @117 mph

Jb4 with wheels: 12 flat @113 mph

I've learned not to get my hopes up too much with the quad. Its not a very consistent and more so than not has let me down. I'm feeling lazy but tomorrow morning, I may take the quad to "the street" and see what she does with the BC wheels. Rain is coming tomorrow, later in the day and swapping wheels is such a PIA... DA was really good today at the beach. Our street is up in elevation and DA will be worse but it's the maximum allowed down slope allowed by draggy. So we shall see.

Ken

P.s. When I took her out today, once again, it felt like lag has been cut in half and man did it pull hard.. I was thinking she is gonna run stock times easily.. sigh, there is still hope, the intake isn't coming out just yet.
 
#28 ·
Ok, I ran a few runs on "The street" this morning and came back pretty disappointed but there was one interesting thing, I got in a 116 Mph run. Which would be fast for stock wheels, let alone my BC 21" wheels. The 115 from yesterday and the 116 isn't a fluke, and that made up for my heavy wheels (mph anyways).

So the notes: Mph kept dropping with each run. 116 for the 2nd run (I blew my first run, hit the revlimiter..) and ending up in the 112 mph range at the end. So either heat soak is getting me or the ECU is offsetting what the JB4 is giving me or both. The slowest mph I ran today was about the fastest I've run with my wheels before. 1/4 mile times were just not going to happen today. The best run of the day, I ran 12.2 but my 60ft was 2.09. I got a 60ft today down to 1.9 but the quad was already running slow. So lets just say "at best", she would run a 11.9 with my heavy wheels and maybe 11.7 with stock. .

Is the intake making a difference? Yes. Mph is up up by around 3-4 mph.

Is the intake worth it? Eh... 1/4 mile times is what matters and at best, I'm still around stock. For sure lag is cut and I think there is a decent gain thru the rev range. I also threw no codes today. Last time I went there with the JB4, I had a few turbo performance codes (which could be a failing diverter valve). So cutting lag will help in this regard. But in the end, if you can't brag about a faster 1/4 mile time, then its all for nothing. The final straw is that you can barely hear a difference. If it sounded way better, than maybe.

Final words.. The quad is just not a numbers only car. If it had launch control and it would be more consistent then I think we would see improvements. I truly believe its making more hp but I think the higher hp might be hurting the launch. I guess if you want a numbers only car, get a Tesla. So until someone releases a proven and reliable tune, I'm bowing out of the 1/4 mile game.

Ken

P.s. I threw a cold start CEL a few weeks ago after the quad sat for over a month. I'm gonna let her sit for a few weeks and see but my warranty will be up here real soon and the stock intake may have to go in sooner than not.
 
#29 ·
One last thing.. It rained on me on the way home and I even took my car thru a touchless (gas station quicky) wash and I had zero water on the filters. Yes it was raining and I got my car washed.. LOL But hear me out, the car was so filthy on the way home that I couldn't use my wipers as it would just smear all the crap on my windshield. I wasn't the only person at the car wash too.. LOL
 
#30 ·
Thanks for the detailed accounts. It could be that your FYI air intake is still soaking a lot of heat from the rest of the engine at take off speeds (0 - ~25-30 MPH) and it hurts the take off. I remember my home made air intake was hurting 3 tenths in the quarter mile consistently (although it felt it pulled harder at higher speeds)...perhaps something similar is happening with your system. I guess you could try to isolate those air filters better from the rest of the engine.
 
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