Subaru Impreza GC8 & RS Forum & Community banner

1 - 20 of 66 Posts

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #1
Heyllo...

So, apperently subarus have same "problem" as rx-7, they got coolant going through throttle body...

How do i fix it? aka: throttle body mod..

Thanx
Alex-
 

·
Registered
2004 Forester XTi
Joined
·
1,005 Posts
Dah dah daaaaaaaah!

I don't know for sure, but I believe that every car manufacturer these days uses hot coolant to flow through the throttle body as a means of keeping the throttle plate from freezing for those bad climate areas. For all the other non-freezing days, it's a heater for the air that goes through the intake runners into the engine. Therefore, we have a 1/4" coolant line into the throttle body and a 1/4" coolant line out of the throttle body.

This is a mod that will cost you no more than 5 bucks (for some of you college students... this will mean no lunch at McDonald's for a day). Go to a local hardware store and buy a 1/4" fitting (brass or rubber. Doesn't matter) that has barbed ends on both sides. My rubber fitting costed $1.19. Make sure your car is not hot. Now take off your air box so you can get under the throttle body. You will see a rubber line on the driver's side of the throttlebody as well as the passenger's side. Take off the metal clamps and then slide off the lines. It will take some reaching and strength for you to get the two lines to slip over the barbed ends. "YOU CAN DO IT!"

Sorry, I'll finish tomorrow. I don't have time now.
 

·
Registered
99 2.5 RS-T
Joined
·
838 Posts
The only thing I'd add is make sure you cap off the inlet and outlet nipples on the TB with vacuum caps or loop a piece of hose from one to the other. The nipples are 5/16" and caps can be bought at autozone for <$1.50.
 

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #4
dope

thanx
 

·
Registered
2004 Forester XTi
Joined
·
1,005 Posts
CAI stage 3; cont.

Now, to finish this SOB... you'll take the 1/4" fitting, slide it into the driver's side rubber line, and use the clamp to snap over one side of the fitting/rubber line. Now, unclip and pull the passenger line from the engine (it should already be unclipped from the TB), connect and clamp the TB side end of the line with the other side of the fitting. (now, you should have the driver-side line connected to the fitting and engine, and the fitting should connect to the passenger-side line that's not connected to the engine) Connect the passenger side line back onto the engine and clamp it.

Boy is correct on capping the TB inlet/outlet holes, but I used aluminum foil and sorta molded them as a cap so they wouldn't fall off. Put your airbox/intake back on and start up the car. Look for leaking antifreeze. ...it shouldn't be if you remembered to clamp all the ends. Go out and have fun. ps- I think Iggdawg on the other club said this mod gave him 3-4 hp and around 5 lbs/tq.

Overall, I've spent $1.19 +tax on this whole mod. This mod took me about 1 hr, because I was working on a hot engine and couldn't figure out how to get the passenger line to slide over the fitting. I found out an hour later... :rolleyes:

*Although the rubber lines may be 5/16", a 1/4" inner diameter fitting shouldn't be a problem. If you were to get a 5/16" fitting normal flow, it'd be a little harder to slip the fitting into the rubber lines. AFIAK, the 1/4" fitting was difficult enough for me to slide into the rubber lines. If you can find a 5/16" fitting, buy it and try if it fits*

*Another note, all the ends of the rubber lines already have a metal clamp (you'll be working on only 3 of them) so you won't need to invest in extra clamps unless you're buying rubber caps for the TB*

CAI stage 4... This mod will work better when you have phenolic spacers installed. That way the engine heat will not heat up the intake manifold by metal to metal contact. This way, only underhood temps will affect the manifold. If I can get the chance to cut some out, I'll try to sell them like what Subachad is doing.
 

·
Registered
99 2.5 RS-T
Joined
·
838 Posts
Kickin, the vacuum plugs don't need to be clamped, the inlet/outlet nipples have enough of a lip to keep em in place. As for the phenolic spacers, go for it! The more available the better. I'd just like to request (already talked to Chad about this too) that you consider cutting phenolic TB gaskets too. The extra 1/4" should help low end and keep the intake air even more therally isolated.

Thanks!
 

·
Registered
2004 Forester XTi
Joined
·
1,005 Posts
Boy said:
Kickin, the vacuum plugs don't need to be clamped, the inlet/outlet nipples have enough of a lip to keep em in place. As for the phenolic spacers, go for it! The more available the better. I'd just like to request (already talked to Chad about this too) that you consider cutting phenolic TB gaskets too. The extra 1/4" should help low end and keep the intake air even more therally isolated.

Thanks!
I do not know of a TB gasket, because I have never taken the TB off. Is it behind the air sensor?
 

·
Registered
99 2.5 RS-T
Joined
·
838 Posts
The stock gasket is paper, thin and reusable if you're careful. The idea is to 1. use phenolics to cool TB/intake charge further 2. add 1/4" additional plenum volume to boost low end torque. Making the gasket/spacer should be pretty straight forward (trace, cut, drill). The V8 guys have used TB and carb spacers for years.
 

·
Registered
2004 Forester XTi
Joined
·
1,005 Posts
Hmmm, that's a good idea, but I think it will only benefit the rpm band if you have already done the manifold spacers and TB bypass like me. Anyways, I'll consider that. :happynow:
 

·
Ntseg Muag!
SRP MY00 Subaru Impreza 2.5RS
Joined
·
518 Posts
hmm.....haha thanxz for the info even though i didn't start this post....this'll come in handy someday.......also just wandering is there any benefits in this mod......what does it do?
 

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #11
Re: CAI stage 3; cont.

kickin_81 said:
ps- I think Iggdawg on the other club said this mod gave him 3-4 hp and around 5 lbs/tq.
Personaly i think that's complete bull! :roflmao:

at most this will give you .5-1 HP because air flows through t-body at such high speed that it will have to be pretty FUCKING hot or cold to chance anything.

This mod and the fuel mod are more to keep reduce wear and tear on your engine rather then gain horsies.
 

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #12
as a matter of fact, you can figure out how about how much you'll gain with this mod.

you'll need some #'s though
temp of t-body before and after mod
volume of air going though the body
that'll depend on your air intake diamiter(2.5 stock, 3" modded)
i had some one help me with this a while ago, as i tried to basically freeze my throttle body in order to cram really cold air in it.

i had to put a 120lb compressor to pump freeon at speeds fast enough to cool air at high rpm, run a bunch of copper tubing all around and through my tbody... bla bla total cost was between 600-1600$ to actually make a difference, and i had to have a water runoff for the ice when it melted after engine shut off.
 

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #13
i have not gave up on idea, i am now thinking of changing AC fluid to something different (there are better cooling fluids, can you believe that shit? :rolleyes: ), making my air box biger and better isolated and routing AC directly into airbox. after i hit 40-50 mph the gains will outweigh the losses.

What you think about them peanuts?:stinky:
 

·
Registered
1993 Miata-T
Joined
·
224 Posts
Actually I think it would provide that much of a gain. Think of how hot coolant gets at normal operating temps, and think of how much it would cool your TB by not having it circulate through it. I think I'm going to do this mod tomorrow along with trying to either find or manufacture a set of Phenolic Spacers for my Intake Manifold and TB. I'm sure it would make a difference. I'm also going to do a 3" Airbox mod and insulate my Ganz. I'm sure there are decent gains to be had with doing all of this. Staying N/A with a 4cyl means making the most of everything that you have.
 

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #15
i read my last ports... seemed like smart shit i said..

i am not saying it would not help, just that you should not expect to be pushed against your seat with all the extra G's you get, you wont even notice it.


I did get a new idea a coule of month ago.. you can tell me what you think about it.

go twin turbo setup, not sequential, but Bi-turbo (think S4)
dividing T-body into 2 and having each turbo power 2 cilinders (1+3, 2+4). Turbo are to be located on both sides, behind the engine, closer to the fire wall. 2 intercoolers inside modified 22b fenders (more space, better look) so they can be at an angle. Why?

Hidden turbos, unique setup, with my brother working in a machine shop pretty cheap, gives me something to do, and making my enineering friends think :)
 

·
Registered
1993 Miata-T
Joined
·
224 Posts
Thats a great idea, but sequential twin turbos with a built engine would provide crazy amounts of boost.. Over 2 Bar.. Why would you want to do something other than that?
 

·
General pain in the ass
98 Superu Impreza 2.5 rs...
Joined
·
3,936 Posts
Discussion Starter #17
the only reason i wanted to go "bi" is cause that would allow me to split tbody apart to make it easier. with sequential i'll have to have one tobody... besides if you want crazy boost single turbo is the way to go.
 

·
Registered
2004 Forester XTi
Joined
·
1,005 Posts
Hello! The throttle body mod keeps the throttle body from not only keeping heat from the throttle body but also from heating up the intake manifold. My car has both the manifold insulators and the TB bypass done, and you should do both if you want the manifold to stay cool. My car has lots of throttle response even after driving for more than 10 minutes.

This may be bad to do but in second gear and at 2000+ rpm, I can repeatedly tap (tap=~30% throttle) the gas pedal and the car would jerk forward and backward very hard. I scared my GF, her sister, and her sister's friend by doing that. Now that's what I call throttle response!

ps- I left the throttle body mod on the whole winter here in Minnesota. The coldest it got here was -10 degrees (not including wind chill). There was no sign of my throttle plate freezing; just loads of torque and throttle response. :D So I'd say it's safe for most areas in the winter.
 

·
Registered
1993 Miata-T
Joined
·
224 Posts
I bought some 1/4" vacuum connectors and Vacuum plugs today, and I'll do this mod tomorrow morning before I leave. I'm going to see if I can get some phenolic spacers one day. I bet having the TB bored would provide even more throttle reponse. :)
 

·
Registered
1993 Miata-T
Joined
·
224 Posts
Well, everything that I bought was the wrong size :rolleyes: For some odd reason, the 1/4" brass fitting that I bought fit, but the plastic ones didn't. Also, don't buy 1/4" vacuum plugs, they're WAY too small, I need to go buy some bigger ones, probably 1/2".. This mod is worth the few bucks it takes, I noticed a definite difference..
 
1 - 20 of 66 Posts
Top