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How to build a N/A-T that actually works. 213awhp for $100
Posted: Tue Feb 28, 2012 4:54 pm
by MikeyMeyagi
figured id share my setup i built for my winter beater, i built it out of spare parts i had laying around. my total cost to build this car was <$100 including the shell.
its a 93 impreza wagon 5mt.

Motor:
2.2 n/a block w 150k on it
2.5 sohc heads
^^ this combo produces ~8:1 comp ratio, SAFE for boost!
2.5 sohc intake mani
92 legacy turbo throttle body and tps. (No iac due to the 2.5sohc TB being wrong for the ecu and the leg turbo TB not having one on it. fast idle is acheived with a emmisions VSV and a toggle switch.)
wrx manifolds/crossover/uppipe w hollow cat
VF39
custom inlet tube made from exh pipe and DSM intercooler hose
wrx top mount, with custom y pipe made from the stock plastic one/DSM hose
440cc wrx injectors
92 legacy SS ecu pinned into factory 1.8 harness (simple and works awesome)
apexi afc to scale for injectors
outback 2.5 clutch
3" dp, to 3" home made catback
techedge wideband.
Notes:
car is currently running 8psi of boost. i have no doubts this setup would handle 10-15psi no problem, but unfortunatly the turbo legacy Hitachi maf sensor is maxed out at 8psi. the outback clutch slips sometimes in 3rd gear, i have a better one, just havent installed it.
the iac situation is mickey mouse. i had a phase2 2.2 TB on it originally, but the ecu didnt like that tps, and the Tleg tps wouldnt fit the newer TB. if the temp is above 40-50deg, it starts and idles no problem. below that, the fast idle switch is needed. not a big deal, just annoying.
This build is the result of me putting my STi swapped 94 legacy away for thge winter and not wanting to drive a n/a car, or a nice car that id care if it got smashed up.
Question reliability? I have beat the absolute crap out of this thing, drifting in the snow, sliding around a lake in 3rd on rev limit for 4-5 hours, and taken plenty of decent trips. it runs perfect.
Want proof? Here you go, this was on a land&sea Dynomite at Kinetic motorworks in NH (stock sti puts down 225awhp on this dyno)

dyno vid
http://www.facebook.com/video/video.php ... 5981035252
heres a pic of the motor
there is alot of mickey moused hackery on this thing, mostly because i didnt really care. it was an experiment, and i wanted to have next to nothing in the project. bottom line is, it works, makes power, and has proven reliable. Winning in my book:D
enjoy
-Meyagi
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Tue Feb 28, 2012 6:28 pm
by Legacy777
Thanks for sharing!
You could get a cheap temp sensor or temp dependent relay that closes around the temperature needed for cold start so you don't have to flip the switch each time. You could try placing it somewhere that would be affected by engine heat so it doesn't activate if the engine is still warm and the ambient is cold. Just a thought

Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Tue Feb 28, 2012 11:50 pm
by kimokalihi
Josh that's pretty clever. Nice winter beater mikey. Wish I had those kinds of parts laying around and a free shell.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Wed Feb 29, 2012 12:04 am
by vrg3
Nice little writeup. I'm envious.
If you'd like, I can try to help you make the phase II TPS work with the EJ22T ECU. I'm imagining a little circuit to switch the voltage range around and simulate the idle switch signal. Shouldn't be too hard.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Wed Feb 29, 2012 2:57 am
by MikeyMeyagi
hmm, yeah that would be cool man, the stupid iac problem is really all thats keeping this from running like a totally stock car. might help others in the future if they want to attempt this on a 1st gen n/a legacy. 215whp would be a huge upgrade for wicked cheap if you buy your parts right
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Wed Feb 29, 2012 3:03 am
by vrg3
Cool, lemme come up with something and get back to you.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 3:23 am
by beatersubi
About time.
Cool build. I've been pondering this type of 'budget' build for a while, but have lacked the courage (yeah, thats it) to tear into my daily wagon.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 4:34 am
by MikeyMeyagi
thats why i did it with this car, i didnt have anything to lose and wasnt really worried if it didnt work. the results are very surprising to say the least. it shouldnt make that kinda power but it just does.... those sohc 2.5 heads flow reallllllly good im guessing
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 6:58 am
by Flatfourced
Inspiring! To the average person it's a little more than $100, but for what? 2-3k from scratch, and you have more hp than a wrx!
Good tinkering sir.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 6:03 pm
by MikeyMeyagi
nah the average person could do this for under 1k if they bought the parts right
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 6:54 pm
by Alphius
1k is a little optimistic I feel:
Decent Impreza Shell - $500
Motor:
2.2 n/a block - $150 from a junkyard
2.5 sohc heads/intake mani - $50
92 legacy turbo throttle body and tps - $20
wrx manifolds/crossover/uppipe w hollow cat - $50
VF39 - $150
custom inlet tube made from exh pipe and DSM intercooler hose - $30
wrx top mount, with custom y pipe made from the stock plastic one/DSM hose - $100
440cc wrx injectors - $100
92 legacy SS ecu pinned into factory 1.8 harness (simple and works awesome) - $40
apexi afc to scale for injectors - $250
outback 2.5 clutch - $150
3" dp, to 3" home made catback - $100
techedge wideband. - $150
Those prices are about what I would expect to pay for all those parts if I didn't have any laying around. Most of that is used/homebuilt with appropriate new purchases where necessary. Looks like right around $2k for the average Joe. Of course a couple things could be cheaper and a couple may be more expensive, and a few could be left out if you didn't care about safety or making it last.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 7:35 pm
by MikeyMeyagi
true, but someone with a n/a 1st get legacy would already have the car and a ej22 block, so theres a chunk of change right off the top. i used a impreza because thats what i had here, a legacy would have made the wiring a hell of alot easier for sure.
you could also get top feed 370cc injectors and eliminate the need for the afc all together, that would save some money also
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 8:09 pm
by kimokalihi
Yeah I'm thinking more like $3K total out the door with purchase of an impreza. Imprezas aren't cheap. Well they are but not $100 cheap. Even some of Alphius' prices are pretty low.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Mar 01, 2012 9:50 pm
by Alphius
Still, it's very cheap for the power if you shop around for deals. Way more power than even a bugeye WRX.
Good budget build.

Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Fri Mar 02, 2012 3:54 am
by jp233
Want to find all the parts, come down to Atlanta and build my 94 N/A wagon back up?
I've got a rebuilt EJ22 sitting right here with rebuilt 2.2 heads ready to be slapped back on it, I guess I'll I'd need is all that pesky turbo stuff.... and turbo Leg's are not common down here whatsoever. Perfectly good car otherwise though, except it's a 4EAT.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Sat Mar 03, 2012 5:11 am
by cj91legss
Dude, that is freaking awesome!!!!!!
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Sat Mar 03, 2012 6:45 pm
by vrg3
Alright, I came up with an idea for a little gizmo to adapt the TPS:
http://surrealmirage.com/vrg3/pics/tps_adapter.png
The idea is that you'd use the Phase II throttle body and then wire this thing in by the ECU. You tap into the TPS Power Supply and TPS Ground wires and connect them to the adapter. You cut the TPS Signal wire, and connect each side to different wires on the adapter. And lastly, you connect the Idle Switch wire to a wire on the adapter. Then you have to calibrate the thing, much like you'd
calibrate the TPS, except instead of turning the sensor you're turning a screw on the adapter, and instead of measuring continuity you're looking at an LED.
I built you one. Wanna test it out? If this works it could be really useful for the community. If you're willing to try it, PM me your address.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Sun Mar 04, 2012 5:05 pm
by beatersubi
Thats amazing, Vikash. To be able to sit down and just whip something out like this in your spare time. If it works, I'll be in for one when I do my swap.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Sun Mar 04, 2012 6:03 pm
by cj91legss
So theoretically we could use a wrx tps with this little toy?
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Sun Mar 04, 2012 6:46 pm
by vrg3
If this works at all, then, yes, I'd imagine it'd work with a WRX throttle position sensor too.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Wed Mar 07, 2012 8:23 pm
by wtdash
Awesome ultimate winter beater.....I figured you'd have something like this in your 'toolbox'. IIRC you already sold your Rob Tuned EJ20 ECU, or you'd have used that? The JECS MAF should let you run 10-12 psi?
I know you can tune in your sleep, and since you have the AFC and a WB sensor, did you consider running the JECS MAF w/this setup? Could you ground the blue (?) wire on the MAF harness to avoid a CEL (probably not an issue w/this setup), and then tune it w/the AFC? I know it'll run Lean w/the JECS on the stock turbo ECU.
RE: the TPS (sorry for the Hijack - MM) - I know this issue comes up a LOT on the Ultimatesubaru.org/forum site, as members constantly want to swap in the newer model EJ engines and this is one of the stumbling blocks. I'd bet there'd be a market across the Subaru forums.
Would the TPS 'gizmo' work w/any of the TPS until Subaru went w/the DBW?
Here is a Phase 2 on top ('99/'00+) and a
Phase 1, OBD2 ('95-98/99) on the bottom.

And the Phase1, OBD1 ('89-'94) TPS:
TD
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Wed Mar 07, 2012 8:48 pm
by vrg3
You can indeed ground the blue wire on the MAF connector (or at the ECU -- it's pin 8 of B58) to prevent a code 49 CEL. An S-AFC might not be good enough to tune around using the wrong MAF sensor, though; the difference in transfer function between the two sensors is nonlinear. I'd sooner swap in an EJ20G ECU (with diodes wired in to adapt the 4-channel ignition to 2-channel), a JECS MAF, and an adjustable or modded stock FPR (if you bump fuel pressure up by about 15 psi you can make the stock 370cc/min injectors flow like the 440cc/min injectors that came stock on the EJ20G). And, of course, Rob's tune is a natural next step after that.
Yes, if this gizmo works at all, it should work with any of the TPSes up until they switched to drive-by-wire throttles, those pictured included. You'd still have to find one with a 3-wire IAC valve though.
MikeyMeyagi - The adapter should have arrived today. Let me know if you have questions when you get a chance to take a look at it.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Apr 12, 2012 8:17 am
by coffeeman885
So...I think this is going to be happening. I have been wanting to do a EG33 swap but since that will cost me >$3K since I will at least have to buy an SVX and my school continues to rape me hard on tuition (not even as much as a kiss first) not to mention that engine doesn't want to go in there anyway. I can probably get most of these parts from other rally folks through alcohol bartering. Do you think this set up will be able to stand up to Rallycross? What trans are you running? I will have to figure out turbos engines first - they are almost like magic to me kinda like unicorns and rotary engines.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Thu Apr 12, 2012 6:01 pm
by Legacy777
coffeeman885 wrote:my school continues to rape me hard on tuition (not even as much as a kiss first)
Yeah they tend to do that....and don't even bother with the lube either...
coffeeman885 wrote:I will have to figure out turbos engines first - they are almost like magic to me kinda like unicorns and rotary engines.
They're pretty much the same, just with a few additional things. I remember when I made the switch, and it just took a little extra time to figure out where everything went and what it did. You'll get it.
Re: How to build a N/A-T that actually works. 213awhp for $1
Posted: Sun Dec 02, 2012 6:12 am
by wtdash
Old Thread update.....or dead>>>
Did VRG3's " little gizmo to adapt the TPS" ever get tested?