View Full Version : 4.9 - intake

12-20-11, 05:01 PM
I dont remember where, but I read somewhere on these forums that air intake system for a Yukon would fit on the 4.9L. Wondering if anyone knew if that was true, and which year yukon would have the same fitting?

this is what i was looking at.


12-20-11, 06:28 PM
$267.90 !!!!!!!!!!!!!!!!!!!!!!!!!!!

For a pipe with a filter on the end!!!

Unless you have done significant modifications to the heads, cam, intake, etc etc, the stock setup with a clean filter can physically flow more cubic feet per minute than your 4.9 could EVER demand. Of course that's no fun and it doesnt give you anything shiny to show your friends but at least you'll still have the 270 bucks in your pocket!

The single most significant performance increase you can give this engine is a few degrees of timing and that costs absolutely nothing.

12-20-11, 09:25 PM
well its my money, and my car. Thanks for not answering my question.

12-20-11, 09:56 PM
You can make ANYTHING fit with a little time and determination. Not sure what you mean by "will it have the same fitting". What do you mean, "fitting"?

12-21-11, 01:32 PM
yeah I didnt know what else to call it.
Honestly dont know the technical names for anything, "fitting": I was generally talking about the way the intake tube was shaped. as they are shaped different angles for different engines.

on the attached image i circled the rubber piece that is oval. (whereas intake tubes are round.)

I put together a cheap intake kit by spectre to test it out. and wrapped it with two hose clamps to secure it.just wanted a better fit thats oval to 3-4" round, i guess.

Spectre modular air intake works fine and i can just get a brute force AEM filter for $40. I just wanted something better looking, like the actual kit .

12-21-11, 05:01 PM
go to the junkyard and compare the throttle bodies

12-21-11, 06:23 PM
I know that the rubber coupling on the car will round out and conform to most aftermarket intake tubes - I've seen tons of examples on Car Domain. Just squeeze it into a circle and measure the diameter. There will be a bit of custom work involved to make anything but the OEM into a true 'cold air' intake as it draws air from behind the headlight rather than behind the hot radiator...

As far as looks go, an old school round air cleaner is another option since the throttle body is the same 5 1/8" diameter as a carburetor.


12-22-11, 04:00 PM
I actually considered that ^^ for my 4.9 swap but the 4.1 intake hat has a snout that points under the hood (above the radiator) so it is probably more effective

Something I would like to do (but have no likelihood of ever trying) is to get one of the dual-snout intakes from a 305 TBI Camaro (car domain pic (http://carphotos.cardomain.com/ride_images/1/614/4761/1534880007_large.jpg))

12-23-11, 09:31 PM
It certainly would be neat however with that alt in the way, you'd have to get really creative! I only use the one in the pic for testing so I dont have to r&r the whole intake assembly over and over...

12-24-11, 08:28 AM
I have my intake filter routed behind my headlight, is that good or bad?

I do apologize for dumb questions I may ask, and I thank you all for your input, just got the car a month ago. never really been 'into' cars until recently.

that pic i posted wasnt mine I just pulled it from google.

could anybody point me in the direction to what timing adjustment needs to be done for it to run better? Easy? never done it, i just dont want to mess anything up.

12-24-11, 09:26 AM
You just want the filter to be shielded from any hot engine bay air. The ballpark estimate is 1hp per every 10 degrees air temp. So if the intake is pulling 120deg air from the radiator vs 70deg outside air, you lose 5hp. It's difficult to build a true cold air intake 'shield' for one of those big cone type air filters especially with such limited space - another reason why I recommend the stock air box assembly over anything else.

There are a number of small mods you can do to these engines, however there are two relatively simple ones that make the most difference. One being a performance muffler vs the stock piece and two, advancing the ignition timing up to 4 degrees from stock. This involves turning the distributor clockwise ever so slightly while using a timing light to watch the notch in the crank pulley move up the scale from 10deg to 14 deg. You will need a timing light and a distributor wrench. This can be risky if you dont know what you are doing because too much advance can give you what I like to call 'ventilated pistons'. The other caveat is you will have to run the highest octane fuel available at the pump. The pro's though are a big bump in power and an increase in gas mileage. I dont know what effect it has on emissions though... Google for more info.

12-24-11, 10:44 AM
yeah had a Flowmaster 80 put on two days ago, ill probably wait on the ignition timing because I dont know what parts are distributor, crank pulley etc.. still learning. probably try to find someone to help... Also yeah I only use the 91 (highest available here) at the pump since ive had it.

Thanks for the info

12-24-11, 12:52 PM
yeah had a Flowmaster 80 put on two days ago,

Thanks for the info

I'd like to see a picture with the Flowmaster on it.

12-24-11, 01:03 PM
When my buddy get his dyno installed in Febuary I'm more than will to put out the money to see the dif between a conicle filter and a stock air box.

12-24-11, 02:02 PM
On an otherwise stock engine?

Zero. :cool2:

12-24-11, 02:34 PM
Well wouldn't seeing a 4.9 dyno be somewhat exciting? :p

12-24-11, 03:13 PM
Sure would! I'd like to see what the 4 degree advance is actually worth. I'd guess 20 at most....

12-24-11, 03:33 PM
SO when I get it on first will be stock airbox muffler (cat is hollowed out, might have 3 inch piping to back it up) timing bump. second I can change out the airbox for my conicle filter set up. I'll make sure runs are done hood down as not to give the cone an advantage.

12-24-11, 03:35 PM
sorry for crappy pictures, im lazy. i included a pic of my ghetto intake so you can point n laugh:lol:

Flowmaster 80 makes it sound like a beast.

12-24-11, 04:20 PM
Interesting you got twice pipes. Did you use the OEM hanger on the RH side? Is she loud? Would be cool if you had a YouTube vid.

12-24-11, 09:31 PM
I bought it at a local shop, they installed it.

I dont have a youtube vid. ill try to record one tomorrow (never uploaded one, but might as well start, right?
but yes the flowmaster 80 is a single in-dual out, made for a camaro i think. I just used the regular pipes, no fancy tips.. and yes its loud, i love it.

also increased acceleration (HP?) runs way smoother than before.

This video was actually gave me the idea for it:


06-08-12, 12:56 AM
I bet that dude didn't vote for Obama!:stirpot:

I've had some intense ideas and dreams of the exhaust system I wanted to do..........but I can't get this car straightened out on so many other issues like replacing "BAD WATER PUMPS" every year! You'll have to see my THREADS N' POSTS......and I've been told I'm long winded too.:yup:

The system I wanted to do was a Magnaflow 94406 which is a combo Resonator/Converter. 2.5 manderal bent pipe and either the largest Magnaflow 14557 or the Camaro/Firebird style muffler either in Magnaflow, Corsa, Walker or Dynomax.

I wanted to achieve a super smooth tame exhaust note or just something different that has not been done before.

My idea of the Magnaflow Cat/Resonator combo came from the very famous Automotive Engineering Journalist "David Vizard". Just Google "Vizard Exhaust Theory" and those articles he wrote for all the car mags. will blow anyone away! Intense scientific reading in engineering and physics from the master himself .:worship:

He designed what he calls a "Pressure Termination Box" which in reality works but no exhaust mfg has ever released a system as complex as his and I don't know why. I even asked Magnaflow Engineers and never got any answer back.......I guess its still about money and not about engineering the best exhaust system per application.

I was not going to go as far as David Vizard did because all exhaust fabrication shops in S. Fl. are idiots, but would've supplemented and tried to implement the idea with the larger Magnaflow Cat/Resonator idea for the "Pressure Termination Box" even-though Magnaflow did not know the chamber volume specs of that Cat. or flow rates of their mufflers to try and calculate the volume according to David Vizards requirements.
Just thinking outside the box.:hmm:

I was going to contract S&S Headers to fabricate and jig-up headers for the Eldorado's and get other local 4.9 owners out to his shop, but he needs the car there in Az. I was working on getting another Eldo. owner to get his car in the shop but unfortunately, Loren Barnes had to close his shop after 41yrs due to the economy. This guy new how to build headers according to the Vizard Exhaust Theory.

Anyway,.......here's the link..and....hang on.....:burn:

I had so many great ideas for this 4.9 but can't get the time or strength to do it and share my ideas here.....