Will a WRX turbo fit on my 91 legacy turbo

pjgaerlan · Post by **pjgaerlan** » Sat May 10, 2003 4:50 pm

My legacy turbo has 131K miles on it. I am curious if I ever have to change my turbo if a WRX turbo will fit on my car?? Will I be able to get more HP out of it? Please help

Thanks

pj
p.gaerlan@attbi.com

magicmike · Post by **magicmike** » Sat May 10, 2003 4:58 pm

I'd read through all the turbo posts, there is a ton of information in there.

or you could just wait for someone to say yes or no.

Mike

JasonGrahn · Post by **JasonGrahn** » Sat May 10, 2003 5:00 pm

that information can be found

here:
hhtp://www.google.com

and here:
search.php

vrg3 · Post by **vrg3** » Sat May 10, 2003 5:38 pm

There's no need for wiseguy responses. I've looked for information on this exact subject for a while and actually haven't been able to find anything conclusive. Even if the information is out there in bits and pieces, it is helpful to have information like this somewhere easily accessible.

From what I can gather, though, it will mostly fit. The exhaust side should bolt right up. The wastegate lines and coolant lines should fit with minimal massaging at worst. The compressor inlet will work fine, naturally, but the compressor outlet comes off at a different angle. The stock Legacy turbo's compressor outlet is kind of angled a bit upwards, while the WRX's is angled more horizontally.

It's possible that clocking the turbo differently could resolve this. I don't know if that's possible or not. It may require removal of the integrated wastegate. A simpler workaround would be to use a different tube coming off the compressor outlet.

In the end, though, it's not clear that the stock WRX turbo would be much of an improvement over the stock Legacy turbo. From what I understand, they're actually very similar. If you're thinking of swapping the turbo, there are better ones that are clear upgrades out there.

Someone please correct or confirm this info.

JasonGrahn · Post by **JasonGrahn** » Sat May 10, 2003 6:08 pm

From what I can gather, though, it will mostly fit.

The bolt holes match up but it does require some massaging.

In the end, though, it's not clear that the stock WRX turbo would be much of an improvement over the stock Legacy turbo. From what I understand, they're actually very similar. If you're thinking of swapping the turbo, there are better ones that are clear upgrades out there.

the stock legacy turbo is anemic at best. A teeny little turbo that works for cruising highways, but not if you want more ooomph. the WRX is a definite upgrade. But if you are looking for upgrades, there are A LOT of other turbos that are out there.. most turbos larger then a stock WRX turbo on a legacy would benefit from an FMIC as well.

-K- · Post by **-K-** » Sat May 10, 2003 8:56 pm

We need a test subject. I personaly don't care for mitsu turbos very much, From a WRX to a Starion and a Talon I don't think they spool very well. I've driven cars with T3's and IHI's that for where they run out, spool up better. I know they were on different cars but I've never been impressed with the mitsu.

JasonGrahn · Post by **JasonGrahn** » Sat May 10, 2003 8:58 pm

Richard Buckners rally car has the stock WRX turbo w/ the stock WRX intercooler. Runs VERY well, VERY fast.

NICO · Post by **NICO** » Sat May 10, 2003 9:36 pm

i did that swap but what u need to no about this swap. first thing everthing will fit like exhuste down pipe and up pipe. 2nd thing all the oil lines & rad lines will work. 3rd thing hear we go we have a 90degre bend on the turbo inlet. wrx use a stright inlet design so the tubes go under the intake manifold and gets air from the air filter. so how do u make it work well u got to cut ur turbo plate the one that holds the uppipe up & holds the turbo to the motor & tranny u got to push the turbo back a bit so u have room 2 put a rubber 90degre there then u got to make all ur intake hoses 2 ur air fliter. it not a lot of work but i keep telling u guys PUT A DOWN PIPE ON UR FACTORY LEGACY TURBO MOTOR 4inch PIPE this will give HP & i bet u guys will be so scared to drive it cuz it so fast. BUT MAKE SURE U HAVE A INTERCOOLER cuz ur GOING 2 NEED IT. also wrx turbo r bigger then ower turbos and will give u boost at top end so u lose low end & bye that time u will lose the race & make the car feel real slow. what can u do to make ur turbo a bit better is find a 1988 FORD THUNDER BIRD COUPE and buy that turbo make sure its a WARNER ISH IHI and take the intake turbine off and the houseing and stick it on our factory turbo but ur still going to need to push the turbo back it eazy. then u need a turbo pontiac sunbird intake pipe the one that goes on the turbo to the throttle body. put it all together & WHAT U GOT A T3 T4 small turbine in the exhute so it spools up so fast & MADE TURBO BOOST AIR GOING IN THE MOTOR but u better have a big intercooler cuz wow u get boost LETS say 30psi + MORE but i ant going to blow the motor up so i stay at 20psi. four all this work & time just PUT A DOWN PIPE & BE AMAZED
ciao NICO -----> i whant this 4 my plate on my car what u think ---I WRX U---

-K- · Post by **-K-** » Sat May 10, 2003 11:47 pm

Wow someone else with the T-bird turbo hybrid!!! I didn't need to move the up-pipe I just milled about .200 off the housing where the inlet mounts and re drilled the flange on the 90 deg inlet pipe. It all looks stock!

NICO · Post by **NICO** » Sun May 11, 2003 2:36 am

K whats up u no ur stuff. how do i like the warner ish ihi turbo on crazy A.
i get mad turbo boost & top end is amazing it comes on at 3000rpm and pulls all the way 2 the top. our factory one starts 2 pull at 1700rpm and dies out at top end. the warner ish ihi is the same size as the wrx turbo but we got the small exhuste wheel so the boost comes on strong. the way u put it on is very smart but i had to hook it up 4 a front moutn intercooler so i had to have the air in let tube pointed parelle to the divers side wheel. K how u like it

magicmike · Post by **magicmike** » Sun May 11, 2003 6:18 pm

vrg3 wrote:There's no need for wiseguy responses.

I was definalty not being a smart ass, I was merely trying to prevent another thread on a previously posted question. But then again, thats not my job is it?

Mike

georryan · Post by **georryan** » Sun May 11, 2003 8:20 pm

So how would you guys compare this turbo method over other methods like getting a different VF turbo or a TD05?

The procedure sounds fairly simple and cheap.

-Ryan

-K- · Post by **-K-** » Sun May 11, 2003 9:03 pm

Well I love it! I'm only running 10-11psi right now (waiting on a fuel pump, exhaust and fcd) full boost at 2100 rpm

but it pulls all the way to redline hard. this is with stock exhaust. I also clocked the compressor to point the outlet straight to the drivers side (like the new VF turbos) because I have an air-water IC. All the pipes match up great. It looks stock unless you know it didn't come with air-water.
I know it sounds easy but... I had to redrill the wastegate mounting holes, take apart the turbo (not too hard if you have a torch for the bolts) change out the bearing that the compressor wheel sits on (there are apparently two hights of the bearings, my vf11 had a tall one the T-bird had a shorter one) If you are good with tools and stuff it's not all that hard, nothing too complicated. I think a real good turbo shop would rebuild yours with the T-bird compressor if they know alot of IHI stuff.
I'm not sure how the small hot side (exhaust housing) will work at higher boost, it might limit HP at top end. But right now it's great, you know how your car pulls at 3-4000? Mine pulls harder and all the way to redline.

NICO · Post by **NICO** » Sun May 11, 2003 9:05 pm

the thing is this i dont no the turbo names like tdo 4 5 6 7 8 9 10 but the turbo when u do this to ur legacy turbo its like a wrx turbo same size. it acts the same way but put a intercooler cuz pistons B FLYING.

NICO · Post by **NICO** » Sun May 11, 2003 9:17 pm

K I HEAR YA ON ALL THAT TORCH STUFF ya it was a bit off work + the wastegate need new holes but what the hell u whant power u do it. o mine pulls all the way 2 the top 2 it starts at 3000rpm. K WAIT DONT DO NOTHING U SIAD FCD FULE CUT DEFENCER. all u need is a one way valve on a sensore. where the factory boost controler is there is a brown senser. that senser has to vacum lines going in it the vacum line that goes to the other sensore black box senser under the brown one get that line stick a one way valve so it can only suck the air from the black box sensore to the brown one & ur fule cut will be gone.

georryan · Post by **georryan** » Mon May 12, 2003 3:08 am

K, That's awsome sounding. Next time I'm on my way home I ought to meet up with you for a quick ride along.

So you guys don't think that a WRX turbo or some other small VF tubo will give you the pull and spool up characteristics that this method puts out?

-Ryan

-K- · Post by **-K-** » Tue May 13, 2003 12:01 am

Well I can't say that some of the VF turbos aren't like that, but mine only cost me a JY T-bird turbo, like $50. I think if I found a WRX one cheap and needed to replace mine I'd do it, but not as just an upgrade. Then on the other hand the stock turbo is so small any upgrade might be worth it. NICO I've heard of it but am a little worried about the check valve "fix" I kinda like the idea that my ECU knows when it's under boost. Maybe when I get an EGT

How many people have done this? If a lot have with no bad results... I need a fuel pump first though.
georryan just let me know when you're going to make the trip, if I'm around we can meet up.

91White-T · Post by **91White-T** » Tue May 13, 2003 1:34 am

I did the check valve thing... Hasn't caused me any problems, the only time I've come close to running lean was when my cheap POS boost controller spiked to 22psi.

vrg3 · Post by **vrg3** » Tue May 13, 2003 1:43 am

If you're fine with completely eliminating the ECU's fuel cut (which I think is an important safety feature), a voltage clamp circuit on the pressure sensor can be even cheaper than a check valve. It would basically make the ECU see boost up until just before fuel cut (12psi or so, right?) and then any boost beyond that would still read as 12psi.

-K- · Post by **-K-** » Tue May 13, 2003 1:52 am

What if you just ramp the voltage, then you could still use the factory boost controler. and you would still have a boost cut only higher. Anyone good with circuts know if it's posible? I do know about the clamp thing but I'm not so good with electrical stuff.

vrg3 · Post by **vrg3** » Tue May 13, 2003 3:15 am

Yup, you could ramp it instead even more easily than clamping it. Then the ECU would always get the wrong value, though...

Both methods (clamp and ramp) have their advantages and disadvantages.

Another method is to clamp it but allow very high voltages to go through, so for example: from -15psi through 12psi, the ECU would see actual boost. From 12psi to 15psi, the ECU would see 12psi. Above 15psi, the ECU would see actual boost.

That would be a bit more complex to design, but I probably could... Give me a few days to find the time.

None of these should need more than a few dollars' worth of parts.

subiekid · Post by **subiekid** » Wed May 14, 2003 12:18 am

so if we switched to the wrx turbo would my wrx ic have bolted right on?

-K- · Post by **-K-** » Wed May 14, 2003 1:30 am

What about from 0psi to 15psi, the ECU gets 0psi to 8.7psi, then the factory boost controler would probably work.

If there is a way to only ramp the voltage above vac, that would be the best, no disadvantages if you still put in the cut at say 16-17psi.

I don't know about the WRX IC pipe. The WRX has a different intake manifold so I don't think it would work, but I could be wrong. It would work with the stock slant IC pipe as far as I can see. Getting the slant IC and a cheap TD-04 would be an idea for you. If you use a T-bird compressor you can clock it the right way and use the factory turbo to IC pipe from any 90's WRX or my Liberty Air-Water. Someone correct me if I'm wrong.

vrg3 · Post by **vrg3** » Wed May 14, 2003 3:22 am

Subiekid, yeah, I think it would have, mostly... It may collide with A/C lines and/or the firewall, though. I don't know for sure. I'm pretty sure all WRXs since 1993 have had basically the same turbo geometry, with the compressor outlet coming off at the same angle. So, the slant-mount intercooler's inlet pipe would fit the same compressor setups as the new age WRX intercooler's. The slant one is smaller, though.

-K-, you would have to ramp with atmospheric pressure as the origin; otherwise the readings wouldn't make sense at all. And, yes, it would be better to ramp above vacuum. It can be done... Some of these more clever designs would require slightly more expensive circuitry, but not too much.

I don't know if it would work right to trick the factory boost controller. The feedback loop's dynamics would be very different, so any control constants would be wrong. I know that the control goes screwy when you use a different solenoid in place of the stock wastegate control solenoid. You're probably better off with aftermarket boost control.

vrg3 · Post by **vrg3** » Wed May 14, 2003 8:19 am

Sigh. You got me thinking. So, instead of sleeping tonight, I drew this:

http://www.graphics.cornell.edu/~v/pics/fcd.gif

I just came up with it off the top of my head, so it hasn't been tested or anything, but I think that would be a workable fuel cut defender.

What the circuit is meant to do is this: the user specifies a threshold voltage (or pressure, same thing) and a slope (amount of ramping). Below the threshold, the reading is passed through unchanged. Above the threshold, the reading is ramped by the amount specified.

So, if you wanted, for example, you could have -15psi to +9psi go through unchanged, and beyond that, the reading would rise 1psi for every 2psi of pressure (so 10psi would be read as 9.5psi, 11psi would be read as 10psi, 15psi would be read as 12psi, etc).

That would give accurate readings until boost gets high, and then the readings would still rise as boost rises, leading to an eventual overboost fuel cut if boost should get out of control.

If the ramping adjustment potentiometer was turned all the way to the right extreme, the circuit would become a voltage clamp, just like many "real" FCDs. If the threshold pot were turned all the way to the right extreme, it would ramp all voltages, just like many other "real" FCDs.

I think this combines most of the advantages of the existing fuel cut defenders out there. And it would consist of just two LM124/LM224 chips, two 1K resistors, two general purpose diodes, and two 10K potentiometers, so it should be cheap to build. Assuming it works.

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Will a WRX turbo fit on my 91 legacy turbo

Will a WRX turbo fit on my 91 legacy turbo

sorry, i'm a wiseguy at heart.

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