Sorry If this has been covered, my searching has not givin me much info.
I'm currently running a 3" Intake and been thinking about stepping to a 3.5"

I've seen some posts stating "the more air the better"... sometimes more is not better so I figured I'd inquire.
Would I see gains stepping from a 3" intake to a 3.5"?????

running a simple set-up
Stock Jdm H22
Sk2 In.Mani
70mm TB
Sk2 Pro2 cams
SSR Header
3" Exhaust

Thanks

 

A few h22 guy are running a 3.5-4 air intake setup here.I have a 3.5 air to with a bpi 3.5 stack that i will test this summer on my car.

 

I have some theorys about what would work but in all honesty, I would go to a dyno and test out a 3" pipe and a 3.5" pipe starting at about 40" long. I would then start chopping 1" of the pipe and making a dyno run to find the "sweet spot" that the motor liked for length, for both pipes. It's amazing what you'll learn when doing testing like this.

 

Currently running a 3" with a bpi, and yeah I've noticed H22 cars running a 3.5"
I'm asking because before buying a new BPI the piping etc. I wanted to see if it woul be benificial

 

I hear unfotunately unfortunately I wont have the time on the dyno to go through testing at this level. I know you stated u have theories (and appreciate you wanting to dyno test before throwing them out there) but at this point would def be interested in your theories

(even if they are only theories at this point)

 

its a well know fact that a length "tuned" intake tube can give you more power!

Wave harmonic tuning with this method is something that you test more with trial and error...

 

I understand where trial and error on the dyno will help me find exactly what the engine is looking for.

Right now, I am running about 20" short ram (most impart due to clearance,- H22 in a crx chasis) I can def with a little work, some chassis trimming and some couplers run more 3" and set up a cold air, which I should've done a while ago. but before I even start Im just looking for Input/suggestions.

 

You can literally use pvc plastic pipe for an intake you make initially and use a chop saw to slice pieces out of it as you go or a piece of exhaust pipe with a silicone elbow and do the same thing. It's cheap and it will help you determine the proper length and size fairly quickly. Once you have that final info you can make a custom intake for your car that will look good and perform.

 

im running a 75mmtb with a 3.5 intake but i have gotten to test it out this season...

 

A abs or pcv 3.5 pipe is hard to find too...

 

What IM are you running with the 75mm TB? I know the Euro R and OEM manifolds can't be bored out enough to except a 75mm TB. Can the Skunk2?

 

I think electrical PVC is 3.5".

 

will look for that thx buddy

 

i went from 264/176 to 270/185 but i also switched headers so i cant say for sure the intake tube made gains, but i didnt go backwards.
3" to 3.5" with BPI stack and 68mm tb. 2.2L bseries

i read in one of tbones threads that he picked up 14whp when he switched to the bigger tube on his 2.2 project 300

 

So I guess only one way to really find out, I just ordered about 40" of 3.5" alum. tubing and a couple of 45deg elbows. I'll scoop up a 3.5 Bpi Stack.

When I hit the dyno in Feb, I will run with my 3" SRI w/ 3"bpi intake. then switch it out with an exact 3.5" dup. just as a comparison.

Hopefully the 3.5 shows some gain, If so I'll have my final tune with the 3.5" run down as a CAI

and see where that leaves me.

 

good stuff. Just remember that you'll need something longer than the SRi length to really see a power gain. Start off with a length of about 40 inches and start chopping an inch off after every dyno pull and watch the power curve, you should be surprised.

 

any updates on this? A friend of mine just picked up a 3.5" BPI stack & a burns stainless 3.0->3.5 aluminum transition

 

haha kinda off topic but one of my friends watched the fast and the furious movie and one thing they said is they put a 4in intake tube to a turbo on a evo and now he thinks that if you put a 4in inlet turbo on anything it will be fast. sorry you are all talking about big intakes and it made me think of it

 

get out^^ ^^

 

what?

 

Off topic and value-challenged post.

 

I made the switch from 3" to 3.5" but I did other things at the same time. Had I thought this were a hot topic, I would have done a back to back comparison. I went from 196 to 217 with almost 30whp difference at my redline.

But I changed the TB/IM/Header at the same time. I'll have to do a real back to back in the spring time for real numbers..

 

first test that i made with my friend on a b18cr I/e/h s300

This is back to back testing 3 inch intake with bpi vstack against 3.5 inch intake with bpi vstack

No air filter on these two pass

 

Second test on another car same day same dyno b18c 11.7 cr pro2 ipg cnc cylinder head etc etc...Run 25 is 3 inch short ram with bpi vstack.Run 26 is 3.5 air intake with bpi vstack with no tuning.All of these test was done with back to back dyno pull

with this kind of setup a 3.5 air intake is a must i think.

 

WOW. thanks for sharing, assuming the red line is the 3.5" intake, that is some serious power advantage right in the meat of the curve at the top. thanks for posting as I had wondered about this.