wrx 3/16" mod

[charliemopps24]

I heard good things about this and i heard bad things about this. Then i read that somebody used a 1/8 or 5/32 size fitting and said they got 85% of the benefit with none of the drawbacks. Any thoughts, cause my buddy wants to drill out the coupler with a 1/8" drill bit.

[CHAOS]

umm... you may want to provide a bit more info.. ive never heard of this... whats the mod for? wheres the fitting? etc etc

[charliemopps24]

http://www.wrxlinks.com/forum/topic.asp?TOPIC_ID=292&whichpage=1
http://www.smegalot.com/316mod/316mod.html

[TROLL]

its for more boost right? eh... it was an old trick that was popular but you dont hear about it much any more. i'd personally prefer a more legit way to control boost like an accessport or custom tune.

[redline]

Don't they refer to this as a restrictor pill?

[charliemopps24]

Well, i showed my buddy all the info and decided that using a 3/16 would be a bad thing since it causes bucking and lag and all kinds of bad stuff. The stock one is 9/128" i.d. He's gonna see what happens when you split the difference and go 1/8". I'll keep you informed on what happens.

[ScoobyNubieToo!]

Well, i showed my buddy all the info and decided that using a 3/16 would be a bad thing since it causes bucking and lag and all kinds of bad stuff. The stock one is 9/128" i.d. He's gonna see what happens when you split the difference and go 1/8". I'll keep you informed on what happens.

I'm gonna save your friend a whole bunch of looking right here:
Originally posted by ScoobyNubieToo

I'm doing a cut and paste of LewisWORX post on another thread. I think he did some good work so I didn't want it to get lost. So here it is "I saw a test of different size couplers and decided to do one of my own. Here is what happened on each test

3/16- I have been using this since I got the car. With my AP stage 2 at 65 F I was over boosting to 17.8 and above if colder on WOT. The acceleration was at times sparadic and it was obvious that the ecu was searching to regulate this overboost. It also gives a heavy lag between moderate rpm shifts. This only makes sense when you think that the size of the restrictor is so much larger than stock that boost cannot be held or released with any compensation to quick gear changes.

stock-9/128 or so- I bought one from subaru. Well all I can say is that it is consistant, but nothing to smile about, something bigger than this is obviously better.

5/64- At this point things started to get better. Acceleration is much much more consistant and regulated. Boost doesn't spike and hits a constant 15.3-5 every single time even in different temps. The studder in moderate rpm shifts are completely gone. Boost spools more quickly than OEM but less quickly than 3/16. It's funny how something as insignificant as a little piece of plastic can make this big of a difference.

3/32- I tried one step bigger. It seems to have all the positives of 3/16 and none of the negatives. Fast spool and boost ceiling of 16.4-8 psi in 3-5. I am seeing around a .5 psi spike before solid boost. Acceleration is much better than 3/16th still and the extra boost adds some kick before redline.

1/8- this is moving in the wrong direction. Overboosting is starting to be over 1-1.3psi. This is where my testing stopped.

conclusion: use 5/64 if you want to hit just under target boost for the AP, use 3/32 for a little over. IN anycase, do not use the 3/16, trust me, you will be glad you switched. As for stock and non EM users, i suggest the 3/32"

[charliemopps24]

The only thing is that 5/64 is almost exactly the same as stock, its only 1/128 bigger. 3/32 is almost impossible to find at hardware stores. 1/8 is still a good compromise. Almost exactly between stock and 3/16. I'll post up tomorrow night after riding with him with it installed and give you my opinion if it is a worthwhile mod. If it's a bunch of bull, we'll just put the stocker back in.

[ScoobyNubieToo!]

The only thing is that 5/64 is almost exactly the same as stock, its only 1/128 bigger. 3/32 is almost impossible to find at hardware stores. 1/8 is still a good compromise. Almost exactly between stock and 3/16. I'll post up tomorrow night after riding with him with it installed and give you my opinion if it is a worthwhile mod. If it's a bunch of bull, we'll just put the stocker back in.

Well, that's up to you but if someone told me this:
"1/8- this is moving in the wrong direction. Overboosting is starting to be over 1-1.3psi. This is where my testing stopped."

I'm not so sure I would wanna use my car as the guinea pig to see if that guy was right or not.....but post back.
I'll look for that engine block next to HUFF's in the For Sale thread :lol:

[charliemopps24]

Well, that's up to you but if someone told me this:
"1/8- this is moving in the wrong direction. Overboosting is starting to be over 1-1.3psi. This is where my testing stopped."

I'm not so sure I would wanna use my car as the guinea pig to see if that guy was right or not.....but post back.
I'll look for that engine block next to HUFF's in the For Sale thread :lol:

My friend kinda laughed gleefully at the idea of 1.5 psi overboost. I think he liked the idea of 16 psi. Almost everybody's aplication is different. You know how some people say that a mod doesn't do a damn thing while others say that it's the best thing they've ever spent money on. Like crank pulleys. IDK? I'll let ya know tomorrow night if it actually does anything good or bad.

[ScoobyNubieToo!]

My friend kinda laughed gleefully at the idea of 1.5 psi overboost. I think he liked the idea of 16 psi. Almost everybody's aplication is different. You know how some people say that a mod doesn't do a damn thing while others say that it's the best thing they've ever spent money on. Like crank pulleys. IDK? I'll let ya know tomorrow night if it actually does anything good or bad.
YIKES! :lol: Well let us know how he makes out. JUst let your friend know that sudden boost spikes like that are very bad for your motor. The whole 3/16ths mod is pretty much dying amond WRX modders. If he really wants some big, safe gains you should turn him on to OPEN ECU....for less than $100 he can tune his own car as long as he reads up carefully and understands what he is doing before he touches anything. BTW if he's fixated on doing the 3/16ths made he can achieve the other diameters mentioned by simply drilling out the piece on either side with a drill bit of that size. Good luck to him!

[Buster]

or you could buy a boost contorller and boost where ever you like. I borrowed this from a friend of mine after I went stage2 and my boost was all over the place. Then I went and picked up a Perrin MBC (this was over a year ago) Have since set it to 17.5 psi and havent touched it again. Dont do it cheap. Cheap screws your car up and leaves you with stupid questions you know the answers to later.

[charliemopps24]

Well, we plugged in the 3/16 connecter and it doesn't overboost at all. The boost does "come on" stronger though. My friend also says his gas pedal is touchier. Nothing bad so far though. Not that big of a change either. IDK