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Old 08-11-2005, 01:05 AM   #1
2milehi
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Default Takin' the plunge, turboing a '98 RS

Been lurking some, searching some, reading some, and replying a little.

I purchased a '98 RS 2.5 10 days ago and 2 days ago I got a '02 WRX turbo (TD04), intercooler, BOV, and some intake hoses.

I was doing some trial fitting and got the intercooler to fit, but the firewall will need a little massaging. A few question come to mind and was looking for some helpful inputs.

The throttle cable - It clears the factory BOV if the hose adapter is taken off, but the BOV can't dump back into the turbo inlet hose. Possible rich condition when letting of the throttle when in boost.

Turbo inlet hose - The factory on fits under the passenger side intake. The stock power steering pump and fuel line on the RS will be in the way. My thoughts are to 45 right off the turbo inlet and to the MAF, skipping the "under the intake" route.

Water cooling passage for the turbo - Didn't dig into that one, how does the factory route that plumbing?

Oil circuit for the turbo - Since the oil outlet is higher than the back passenger side wrist pin access hole, plumbing into that should be easy enough. As for oil pressure is there only out outlet to tap into (pressure sensor location)?

Header vs. WRX manifold - Header are plentiful whereas the WRX manifolds are in limited supply. Any recommendations on a good yet fair priced header or use a WRX manifold to get started.

Thanks,

Mike
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Old 08-11-2005, 01:27 AM   #2
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I was browsing and saw your thread. congrats on the turbo project/thought. you must know already, but dont run too much psi or your new RS will become junk real fast. anyways, check out Megan Racing. They make a header/up pipe combo for 499$. a SUPER good deal considering up pipes are 200 ish and headers are 500 ish. now heres a catch. you have 2.5L's while wrx has 2.0 obviously.... I dont know if they will fit. like the diameter of the header tubes might be smaller for 2 liters and bigger for the sti's 2.5..... look into getting a factory sti header/ uppipe... so the liters will match... I dont know if the up pipe flanges are the same when comparing wrx to sti but its a 90% yes. Keep me updated on the project, I have an 03wrx so I'll send you pictures of anything you need to help you with routing or re-routing. Later
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Old 08-11-2005, 11:21 AM   #3
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Thanks sc00bywagon And yes I won't be dropping 20 PSI of boost on my first pass. I'll be starting with about 5 psi and go in small steps. Also with a 9.7-1 compression engine, I don't see getting much higher on pump gas.

Seems like WRX stock header would be a good start.


Test fitting, intercooler is snug...
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Old 08-11-2005, 12:20 PM   #4
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Try the aftermarket forced induction forum. There is a wide body of knowledge there about this sort of thing. You will need a turbo crossmember, or an aftermarket up-pipe (made specifically for this application) as well as tapping your oil pan for turbo oil return, etc. etc. Change forums and you'll get way more replies...
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Old 08-11-2005, 03:57 PM   #5
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You can use subachad up and down pipes for your TD04. GET A STANDALONE.
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Old 08-11-2005, 08:17 PM   #6
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Quote:
Originally Posted by blaznc
You can use subachad up and down pipes for your TD04. GET A STANDALONE.
And use you stock y-pipe. If you want to go WRX exh manifold then you will have to swap to a wrx or legacy turbo x-member.

Good info in the FAQ.

And here: http://forums.nasioc.com/forums/show...hreadid=197549

Get ready to be very poor like the rest of us.
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Old 08-12-2005, 02:06 AM   #7
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The X member can be notched thats what i did with my legacy one. I am thinking about reinforcing it but there are a few allready on the road with notched Xmembers working out just fine. As for the coolant i tapped the hose that goes to the heater core and then T-ed the return line so the flow would be constant in and out. And the Oil, i used a "sandwhich" adapter which is more commonly used for an oil cooler . Wrx headers will work and the diameter should be identical. 2.5L , 2.2L and 2.0L motors have dual port heads, i dont know about 1.8s but you dont have to worry about that, they will bolt right up. As for engine management, I am running a Greddy Emanage so far so good with the turbo legacy ball valve injectors (pink top). hope this helps, Good luck!
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Old 08-12-2005, 12:43 PM   #8
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Thanks for all the great input! I felt that since I was using 2.0 factory turbo stuff, that this topic belongs in there. Guess I took "Aftermarket Forced Induction Powertrain" to literal. My bad...

Anyway, a few points.

Quote:
Originally Posted by Tats
And use you stock y-pipe.
Gonna get away from this. The two pipes joining together at a 90 angle doesn't look good for flow.



The stock turbo manifold looks better.


Quote:
Originally Posted by Matt Monson
...as well as tapping your oil pan for turbo oil return...
It seems a lot easier to utilize the back passenger side wrist pin access hole than to remove the oilpan, drill, tap, and reinstall the oil pan. Any reason why this would not work?

Quote:
Originally Posted by Kawikid20o2
The X member can be notched thats what i did with my legacy one
You notched a factory N/A cross member or a turbo one? In the pic below one can see where notch needs to go (upper Xmemeber).



For fuel management and tunability...

msefi.com

It does fuel and DIS with a few JY parts (off a Ford 4-banger). All for about $250 but I have to ditch the stock 'puter.


Seems like I'll be getting some mandrel bends and break out the MIG for the up-pipe. And some more reading to do.

Last edited by 2milehi; 08-12-2005 at 12:57 PM.
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Old 08-12-2005, 01:16 PM   #9
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Umm,
That wrist pin hole is going to be covered by the mating of your tranny?
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Old 08-12-2005, 06:01 PM   #10
2milehi
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Quote:
Originally Posted by Matt Monson
Umm,
That wrist pin hole is going to be covered by the mating of your tranny?
There was an allen "plug" that was on the back of the passenger side block that was located below the head and visible to my eye. I assume this to be the wrist pin access hole...thinking...it could lead into a cooling passage hole....doh!
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Old 08-15-2005, 10:30 PM   #11
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I have a set of Pauter rods for a 1998 RS and a Blitz BOV adapter for the WRX intercooler.
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Old 08-16-2005, 12:27 AM   #12
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Quote:
Originally Posted by CUNNINGHAM
I have a set of Pauter rods for a 1998 RS and a Blitz BOV adapter for the WRX intercooler.
Keepin' the inners stock (for now). How will the Blitz BOV adapter help with the current clearance issues?
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Old 08-16-2005, 09:42 AM   #13
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It will give you no benifit other than you can run the blitz BOV without any mods.

I would Think about internals.
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Old 04-15-2006, 01:23 AM   #14
2milehi
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So I finally got the turbo/intercooler in and running

I did go about it the DIY way and I'll spell out the PROS and CONS that I ran across...

SMILE - I notched and welded in a reinforcement to the crossmember. Since I had to unbolt the original crossmember, I could have foregone the building of the notch and installed a notched crossmember. It took some time to fit the notch in but wasn't too hard to accomplish.

SMILE - Up-pipe - it has to be done. I took a factory one and extended it about 2.5 inches to push back the turbo so that I could rearrange the turbo intake inlet.

SMILE - Down-pipe - used the factory one. It bolted to the tranny and I used it as my guild for constructing the up-pipe. I welded an O2 sensor bung prior to the cat.

FROWN - Turbo suspending mount - the WRX one does not bolt to the block/tranny (or I could not figure it out). With some 1/2" angle iron I managed to construct a solid mount for the turbo.

Turbo oiling and cooling - BSPT - WTF!!!! I got oil from the oil pressure switch with a T-fitting with the assistance of my 1/8" pipe tap. The BSPT is almost the same as the American equivalent, so I ran the tap through and used sealant on the fittings with no leaks. I soldered one of the pipe threads shut and drilled a 0.07" orifice for an oil restriction. The oil return was a 3/8" pipe tapped into the passenger side valve cover and I installed a 90 5/8" barb. For coolant I used the throttle body's coolant line and tapped into that via adapting the banjo fittings with "barbs". Again no leaks and is working.

SMILE - Rotate turbo housing inlet - One needs a big pair of snap ring pliers to do the job and once the correct phase is determined, then a small hole needs to be drilled for the aligning pin.

FROWN - Intercooler - the factory dual inlet interfered with wiring and AC piping. I capped off both inlets and added a side feed like in the pic provided by CUNNINGHAM. Once that mod is done the intercooler fits great

Factory wiring needs to be moved - not a big deal.

Water pump need to be changed to a WRX style one. This involves messin' with the timing belt.

Waste gate actuator - this part SUXS! Since the turbo inlet is rotated, the actuator will no longer fit in the stock location. I had to build some braces to support the actuator and this part of the job turned out the cruddist. I did manage to guess at the working PSI of the waste gate actuator at 5 PSI.

ECM - the car fired up and ran with nice manners. Finally threw a CEL since I have not installed the rear O2 sensor.

Overall the car runs great. It felt great to pull the car out of the garage and immediately hear the turbo spool up and the car lunge forward. I was lit up like Christmas tree when my first stomp reveled 5 PSI boost. The car ran like before, but had an extra kick when the turbo spooled up.

Unless you can fab up stuff, weld steel and aluminum, and have time and patients, DON'T TRY THIS ONE! Pics and edits to follow.

PS - With my beer buzz on, I don't feel like grammer checking write now.
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Old 04-15-2006, 11:50 PM   #15
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Here is a pic of the final product. I added the other O2 sensor and the CEL went away. Just drove it 75 miles from 5500 ft. to 11,000 ft and back down to 10,000 ft, without a single down gear once up to highway speed. I needed to figure out something with the BOV. The turbo is very noisy from surging when letting off the throttle when in boost.


Last edited by 2milehi; 11-07-2008 at 03:02 PM.
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Old 04-16-2006, 01:18 AM   #16
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I have to say... VERY NICE.

I almost can't tell it'sa DIY... serious that is a clean job, very well done. *CLAPS*

Nick
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Old 04-16-2006, 08:12 AM   #17
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That surging is very bad for your turbo, You can remove the EGR valve, and then install the WRX BOV or Just have one welded to the side of the inwtercooler or charge pipe. Also being a MAF you may have trouble with it stalling if you blow to the atmosphere. You can install a S-AFC and use the decell function or buy a management unit. I looks very clean most guy's just hack it all in there. GREAT JOB!
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Old 04-16-2006, 10:13 PM   #18
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Sko and CUNNINGHAM - THANKS for your kind words. I have done muscle car V8 stuff for a while and started playing with a turbo car a couple of years ago (Dodge Daytona). I have removed, rebuilt, and replaced plenty of engines, but this is my first turbo upgrade.

As for the compressor surge, yeah it does sound bad and I will do something this weekend about it. Until then I drive very grandma like...most of the time.

PS - Some of my inspiration came from CUNNINGHAM's pic from 8 months ago. Many other ideas came from searching in the NASIOC's forum. There is a lot of great info here!
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Old 04-17-2006, 02:24 PM   #19
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looks awesome man, good luck with it.
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Old 04-18-2006, 07:24 PM   #20
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if anyone is trying for the RST i would suggest talking to Xcceleration.com. they helped me out. but i do say good product but a bit pricey. i still doing research.

james
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Old 04-23-2006, 03:58 PM   #21
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i was thinking about using 98 heads for a turbo project. have you considered adjusting for more lobe seperation?
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Old 04-24-2006, 12:21 AM   #22
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Quote:
Originally Posted by Will98RS
i was thinking about using 98 heads for a turbo project. have you considered adjusting for more lobe seperation?
That is the beauty of having the intake and exhaust cams separate! I'll need to figure out if I can use offset keyways. I really don't want to pay for four adjustable sprockets for a small amount of gain.

And speaking of gain - My first tank of gas yielded 20 MPG I disconnected the battery when I was MIG welding on the car and was testing out the new installation. I got 28 MPG on the second tank and today's roadtrip topped at 30 MPG!

The best I ever got was 28 MPG. I figured that with "nice" driving, a turbo engine should get better mileage than a NA (of the same compression). At part throttle on a NA engine, the intake stroke will induce pumping losses. The same engine with a turbo will reduce/eliminate the intake loss because of some pressure delivered by the turbo.
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Old 04-24-2006, 02:41 AM   #23
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*whispers* don't forget EM of you can forget about your motor especially when you start turning up the boost, and you will want to turn up the boost... and please get a BOV. Beatiful job!!!!! ^thumbs^
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Old 04-24-2006, 03:14 PM   #24
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keep me posted on the cam issue. i havent really looked into it much. whats the stock over lap? any danger of piston valve interference with less overlap?
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Old 04-24-2006, 10:03 PM   #25
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Quote:
Originally Posted by blaznc
*whispers* don't forget EM of you can forget about your motor especially when you start turning up the boost, and you will want to turn up the boost... and please get a BOV. Beatiful job!!!!! ^thumbs^
Yeah, it is very tough to resist turning up the boost. I am ignorant when it comes to Subaru's EM systems. And seeing people spend $2500 on a stand alone system scares me I am leaning toward the MegaSquirt & Spark since it can control fuel & spark for around $200.

My ears are open to any "reasonably" priced tunable EM system. Until then I will slap my hand every time I touch the waste gate actuator
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