None such exist. You can get a TB spacer or you can Port and Polish your stock one. That's about it. You really aren't gonna see big gains from either though (if any). These aren't Hondas with restrictive airways nor are they domestics that have 90mm MAFs for their V8s.

 

Mine just went kaput, I wish there was a cheap upgrade

 

Using FalconRS's example of a V8, consider that the ubiquitous 5.0L Mustang made 225hp through a stock 55mm throttle body. The stock TB on my '97 EJ25 is 60mm. (Or maybe 62mm? It's been a while since I measured it.) So the TB is plenty big for the power that the engine puts out.

 

All subaru EJ TB's are 60mm.

But it would still be nice to have an option or two...

 

just hook up a leaf blower to your intake track and it will add like 15 hp. seriously. people have done it before.

 

Lol imagine riding around with a leaf blower sticking out of your hood.

 

Isn't the stock intake manifold supposed to be the more restrictive part? So why doesn't anybody make an aftermarket one?

Also is the throttlebody spacer compatible with after market CAIs?

 

throttle body spacer compatibility depends on what year you have. People don't make aftermarket intake manifolds but people with older RSs (like 04 and below) swap out their OEM intake manifold for newer manifolds which flow better (05 and up).

 

just hook up a leaf blower to your intake track and it will add like 15 hp. seriously. people have done it before.

I seriously hope your kidding.

throttle body spacer compatibility depends on what year you have. People don't make aftermarket intake manifolds but people with older RSs (like 04 and below) swap out their OEM intake manifold for newer manifolds which flow better (05 and up).

Except that the 05 and up are a real tough conversion as there's no mounting for a throttle cable (05+ is DWB) and several things like sensor locations and mounting points changed. You can do it, you just need some creativity.

 

I seriously hope your kidding.

Actually... Theres a video on youtube that is quite serious and has dyno proof.

 

Kost how did you pop your TB? We may have an extra from our parts engine for sale... PM me if interested.

Chris

 

Actually... Theres a video on youtube that is quite serious and has dyno proof.

Actually....that video on YouTube is a well known internet hoax in the car world that's been circulating on forums since before YouTube existed.

 

there are aftermarket intake manifolds but not for N/A applications. I do think a good ITB, would rock. I have been wanting to build one for a while, and if I ever find a set of matching throttle bodies I might try. The CAM shafts/valve train are the restriction for N/A motors. Yes the heads flow really well but the Cams could be a lot better.

Oh and I say the leaf blower is for real. I don’t think it would do much but it would add horse power.

 

Oh and I say the leaf blower is for real. I don’t think it would do much but it would add horse power.

Nope, it's not.

 

Nope, it's not.

How can you say that? proof? any positive pressure in the intake would gain power. all you have to do is flow the same CFM that the engine pulls under vacuum and you would have power. I am sure a leaf blower could put out much more than that. Now I am not saying that it would do a lot but it would do something and I am sure you could dyno the difference.

 

FYI, the EZ30 throttle body is 70mm...

Kost how did you pop your TB? We may have an extra from our parts engine for sale... PM me if interested.

Chris

The bearing is starting to go bad. Its thouroughly cleaned and still sticking

I have a lead on a TB right now, but if that falls through ill let you know.

 

How can you say that? proof? any positive pressure in the intake would gain power.

Airflow and air pressure are not synonymous.

Airflow through a fan cannot create positive pressure. See the thread on electric superchargers. You need:

1. No way for the air to sneak backwards (IE reverse airflow through the gaps in a fan blade when the air can't overcome 0 vacuum to produce positive pressure)

2. A strong enough electric motor that doesn't stall out when a COMPRESSOR WHEEL (MUCH different from a fan) reaches into positive pressure.

There's a MASSIVE difference between a compressor and a fan. I suggest you kids read up.

 

you missed my point, you don't have to create pressure at all, you only need to flow more volume than the volume of the engine can. If you can achieve this than the motor no longer needs to expend energy to fill the cylinder with air. that energy that was spent pulling air into the block is gained back. So like I said all you need to do is flow more than the engine can suck.

 

you missed my point, you don't have to create pressure at all, you only need to flow more volume than the volume of the engine can.

Much like my point went over your head. You CAN'T get more air in than the engine can flow WITHOUT positive pressure. That's the whole point of boost.

If you can achieve this than the motor no longer needs to expend energy to fill the cylinder with air. that energy that was spent pulling air into the block is gained back. So like I said all you need to do is flow more than the engine can suck.

Without positive pressure, the cylinders will still fill with the same amount of air. Oxygen + gasoline = power (extreme layman's terms, but applies here). Further, the intake stroke itself isn't responsible for all the air coming in. A large portion of it comes from the scavenging effect, which isn't assisted without positive pressure.

How bout I put it to you this way:

Leaf Blower: $69
Cold Air Intake: $250

Q: If it really worked, why would you even bother spending money on an intake for a 5 hp when a leaf blower gets you 15?

A: It doesn't work.

It's a hoax. A hoax that's been around since the beginning of sport-compact performance (IE long before most of you were driving or even thought about driving).

 

Can some one clarify please... I was planning on port/polishing/knife edging my throttlebody one of these weekends coming up.

If there are no gains to be had, then I won't try this shit, as I don't want to fubar the throttlebody.

As if my screenname doesnt make it blatantly obvious... I have an '04. With the plastic intake manifold. If that matters at all.

 

you can try but honestly, it's not worth the gain. the most you'll get is a little throttle response and menial hp gain. like kost said, our throttle bodies are plenty big for the amount of power our engines put out.

 

Thanks... I think I'll try it then.

Like others have said.. the EJ251 is plenty efficent... staying the N/A route just means having to do the little things. I guess this would fall under the TB Bypass Mod then. But I like DIY projects... keep my weekends busy.

I'll make it a throttlebody mod day... the by pass, port/polish, and install my TBS when ever area1320 mails them out.

 

be sure to tell us what kinds of gains you see i'm sorta interested in the spacer and i've already done the bypass

 

Hey can someone help clarify this for me-

I plan on port/polish/knife edge the intake side of my throttlebody (as stated in above posts). I can use a dremel just fine and have polished metal etc... but have no experience p&ping, SO as a saftey precaution I want to get a backup throttlebody (in case I FUBAR mine).

So I found a few used throttlebodies for ~$60 on car-part.com (with 60k miles on it) but they are from 03-04 Forresters. For whatever reason, the vendors that had "Impreza" throttlebodies wanted like $150+ for the shit.

I just wanted to verify that it is indeed the same part, and that its interchangable. I have an '04 RS.

Or does anyone else have a source for a EJ251 throttlebody for cheaper? Searched the classifieds and nothing.

Thanks!

 

i don't know if any of you guys have seen this thread before, but over on i-club someone posted about the similarities between an LS1 throttlebody and a subaru throttlebody
http://www.i-club.com/forums/showthread.php?p=1779387
nobody has posted anything for a while so i think the thread is officially dead, but i would really like to see if it could be done