Recently traded my '05 hemi for an '08 QC 4.7 6 speed stick. I had a homemade abs pipe intake on my hemi, and built a similar one for this new truck. However, at WOT, the drone from 3K to 5K is almost unbearable. Is this common with all intakes on this motor? Not used to it being that loud. The hemi was loud, but didn't drone. It only happens at WOT.

Would it be better to reinstall the air hat & only modify the filter box? Does this have anything to do with it being an overhead cam motor as opposed to pushrod?

This is the temporary setup ont he 4.7 (kept my exhaust pipe after adding a turndown...plan on using the last 2 feet of pipe as a3" intake tube) Thanks for any info.

 

Hey man i recently purchased an 08 4.7L w/ 6 spd. I was wonderinghow youmounted to the intake sensor that sits about halfway down the stock intake? Also have you seen CAI's for the year/motor combo? What size pipe are you using? Have you noticed an increase in MPG?

In my opinon... if you think of the air passing through your intake the same as blowing across a beer bottle then: the more liquid in the bottle the higher the pitch (less volume in bottle), and the less liquid the lower the pitch (more volume). I would suggest to reduce the unbearable drone, i am assuming it is too high pitched, either a) increase the size of the intake tubing but i would suggest not going larger than 3" ABS/PVC; or b) increaseing the length of tubing. Both ways equate to larger volume, looking at the picture you posted i would guess you used 2 or 2.5" abs/pvc. 3" will get bulky so i would suggest 2.5" PVCI know this is hard to find but could help. Try the electrical deptartment at lowes/home depot the gray schd 40 conduit uses the same fittings as white PVC or ABS. just my .02 worth.

Thanks

 

As far as the sensor, I just drilled into the abs corner and used rtv to mount the air temp sensor. For the breather hose, I did the same but mounted a brass nipple into the bend right by the filter.

All the fittings and tubing is 3". The drone is right at 3000-3500 RPM...just overwhelming. And believe me, I LOVE the sounds of an opened up intake, but this is a bit much.

Far as milage, I've only put 400 miles on the truc since I got it Wednesday...can't vouch for an increase.

 

my stock box makes a slight noise rollin into the peddle after shifts kinda nice IMO lol.

 

How often are you going to be pushing 3000-5000 rpm's? If that is the only time you hear it, I would not worry about it.

 

http://www.autospeed.com/cms/article.html?&A=109217

 

Good point peddler. Not as bad under normal accel. but you do hear a dramatic change in tone @ that RPM.

 

Hank, interesting article. I know I need to get the filter pulling cooler air outisde of the engine bay...just testing this one. Maybe using the stock system isn't so bad??

 

You can eliminate the 'drone' in either of three ways:

1. put a T fitting in the pvc pipe and attach a length of pvc pipe in right angle pening of the T fitting with a cap on it. By trial and error, adjust the length of this 'stub' pipe to kill the drone. ( in engineer-speak you have made a 'Resonating Stub Trap Filter' )

2. buy two 3" to 6" adapters with a length of 6" pipe
and by trial and error
insert this larger pipe section into your existing piping at various spots with various lengths of the 6" section. (in engineer-speak you have made a 'Helmsholtz Resonator')
Note that Dodge uses these style Resonators in the exhaust pipes to kill MDS noise, and also uses the same principle in the size of the 'plenum' space in the factory airbox.

3. put the stock Ram air intake back on, and like the Autospeed article by self taught auto engineer Julian Edgar, do some air restriction tests at full throttle (or measure the MAP sensor with a Scangauge) before condemning the oem factory design as being 'restrictive' until the numbers prove this to be the true situation.

Don't be a WAG'er (wild a$$ guesser)

Your father, grandfather, and great-grandfather's generation already have done these experiments and figured out the science..... and hope that you will acquire this knowledge and pass it on truthfully to the next generation

 

Thanks for the info. I was really just interested in info regarding the actual drone itself and the difference in sound regarding this motor and my last one. I understand the purpose of the stock airbox, etc. and the little difference a homemade job may make....so I guess I'll throw the air hat back on for now.