turbo on a NA motor

turbotank · Post by **turbotank** » Mon Oct 31, 2005 11:39 pm

i have a 91 legacy with 130k. i just bought a 1991 turbo ss awd. i'm putting the awd in the first car cause it's in better shape. how bad will it be to put the turbo on the NA motor??

dwreck30 · Post by **dwreck30** » Tue Nov 01, 2005 1:14 am

Why not just put the SS motor in the LSi?

turbotank · Post by **turbotank** » Tue Nov 01, 2005 1:48 am

the ss has 190k on it

dwreck30 · Post by **dwreck30** » Tue Nov 01, 2005 1:54 am

Well it is a subaru. Depending on how well the SS motor was taken care of I would choose it over turboing an N/A.

douglas vincent · Post by **douglas vincent** » Tue Nov 01, 2005 2:23 am

If you are smart enough to swap the running gear, you are smart enough to rebuild the motor.

555BCTurbo · Post by **555BCTurbo** » Wed Nov 02, 2005 5:30 am

My SS has 186k on it's motor, and it gets beat on all the time, and still runs awesome and doesn't smoke or burn oil!!

snowboarded · Post by **snowboarded** » Wed Nov 02, 2005 2:40 pm

Or drop your SS motor into a 2.5RS shell.

Matt Monson · Post by **Matt Monson** » Thu Nov 03, 2005 10:43 pm

snowboarded wrote:Or drop your SS motor into a 2.5RS shell.

blaphemy. Somebody ban this guy!

The problem with putting the turbo on your NA motor is you will have to pull the motor and change the crossmember to do the swap of turbo parts. So, if the motor is coming out, it makes sense to change everything to factory turbo.

Consider rebuilding the turbo engine while your other car still runs fine. And the wiring isn't very hard. You only need to change 6 wires and add the ones for the boost control and pressure sensor, etc on the passenger side. IIRC it is something like 12 wires you need to bring in. Knowing what I know now, I could do it without removing the dash...

dzx · Post by **dzx** » Thu Nov 03, 2005 11:13 pm

I say boost the engine till it pops. Then put the turbo engine in it.

Matt Monson · Post by **Matt Monson** » Fri Nov 04, 2005 12:51 am

I would say the same if it weren't for the crossmember issue...

dzx · Post by **dzx** » Fri Nov 04, 2005 2:14 am

Oh, I thought he was going to use parts from the SS. Yeh, a crossmember makes things more complicated.

Natoe · Post by **Natoe** » Sun Nov 06, 2005 9:35 am

pm'd you matt...

turbotank · Post by **turbotank** » Tue Nov 08, 2005 6:47 am

i think now i'm going to rebuild the na motor and lower the compression. thank you for pointing out that i will need to switch the front sub frame. i was not aware that they were different. i got a td04 and a cat less down pipe from a 02 wrx. i am going to get a header for a wrx also.

does anyone have any dyno info to show the diiference between a unequal length header and an equal length header?

also i know the computer system in the car is pretty old. can you reflash the computer in these cars' to tune them. or can you buy a plugin tuning system. i have this dos program that i am suppose to plug into the car and read vital signs. can i work with this program?

douglas vincent · Post by **douglas vincent** » Tue Nov 08, 2005 7:16 am

Currently, I am shoving 10 psi through my STOCK 1991 NA 2.2. NO engine management. STOCK NA timing. No intercooling. Upgraded injectors from 270 to 370cc. Trimmed MAF signal by 5%. Stock NA 9.5-1 compression. Crazy is not the word for it. I blew up (ok, just shattered pistons) 2 motors before this with the same setup intercooled and I don't understand the difference. Possibly I have a lower compression motor now, just don't know.

Anyway, I am making roughly an additional 8 hp per pound of boost. So I am getting around 210 chp which is about 180 whp. I have a dyno chart on a Mustange dyno showing proof of 152 hp, 160 torque at 7 psi barely running on 4 cylinders and fuel pressure at about 30 psi (I had an ungodly clogged tank sock.)

My point?

The 90-94 2.2 NA engine is plenty strong to hold low end boost, probably up to 12-14 psi.....if you engine management it. And if you simply swap in some low compression pistons, probably a whole lot more.

206er · Post by **206er** » Tue Nov 08, 2005 8:05 am

like turbo pistons?
or what about ej20g heads on a stock NA bottom end. that should be pretty low with that huge volume.

douglas vincent · Post by **douglas vincent** » Tue Nov 08, 2005 8:11 am

Turbo pistons, yes.

As for the heads, I personally don't know that answer.

douglas vincent · Post by **douglas vincent** » Tue Nov 08, 2005 8:13 am

Turbotank, the ECU is non-hackible. You need to get some sort of piggyback or standalone to mess with it.

However, as I have shown, you can boost up to 10 psi with the stock ecu. If you were to even get a MSD DIS-2 then you could pull timing which is pretty damn important.

sammydafish · Post by **sammydafish** » Wed Nov 09, 2005 9:28 pm

the motor I'm running right now has over 200k on it. running strong at about 6psi right now. I've got a small oil leak to fix, then I'm going back up to 10psi ... gotta start buting premium fuel again though when I do that

Matt Monson · Post by **Matt Monson** » Thu Nov 10, 2005 12:53 am

206er wrote: or what about ej20g heads on a stock NA bottom end. that should be pretty low with that huge volume.

It's a pretty good set up. I know a couple of guys running Ej25 heads on an Ej22E bottom end. CR is 8.6:1 Good for a good 12-15psi of intercooled boost.

206er · Post by **206er** » Thu Nov 10, 2005 4:15 am

sweet, what headgaskets are they running and which ej25 heads?

Matt Monson · Post by **Matt Monson** » Thu Nov 10, 2005 6:10 pm

phase I Ej22 head gaskets...

If anyone else needs info, PM me. I am on dial up and don't have the patience for Sammydafish's freaking Jaguar to load everytime I go to check up on the thread!!!

206er · Post by **206er** » Thu Nov 10, 2005 8:08 pm

that should be removed by the mods shortly.

Post by **Legacy777** » Thu Nov 10, 2005 9:42 pm

removed.

91l-t · Post by **91l-t** » Sat Jan 14, 2006 2:28 pm

i turbo'd my 91 n/a, but used the turbo ecu wrx intercooler and i had to run 94 oct. never had motor problems and the block had 230,000kms

Kelly · Post by **Kelly** » Sun Jan 15, 2006 11:22 pm

Crossmember isn't that big of an issue.

http://rallitekforums.com/forums/attach ... entid=1492

And I SO would not bother putting a turbo on an NA motor, especially a 2.2 For the amount of work and money it takes.

legacycentral bbs

A forum for 89-94 BC-BF(BJ) Legacy Owners and Fans

turbo on a NA motor

turbo on a NA motor

thanks for the input