Jump to content
Ultimate Subaru Message Board

Does anybody Run a Turbo with NA compression?


Recommended Posts

Just curious, cos if you lowered the boost, had some kind of water injection and an IC, wouldn't this give better low rev power plus the top end of a Turbo?

 

What has to be done to MPFI heads to fit the turbo?

Is it just the Oil and Coolant points?

 

Found a complete 92 mpfi wagon (not roadworthy, crashed) for less than $500

Considering turboin the motor:brow:

 

Thanks in advance

 

 

Gannon

Link to comment
Share on other sites

I run a Carby shortblock with turbo heads/intake and a TD04 from a 2003 WRX.

 

Top end seems a little lacking, but I wasn't terribly interested in top end when I built the motor.

 

Low end is improved, and its nice to be able to actually cruise around town without ever actually having to spool up. But with the higher compression, when I do want the boost, I don't have to wait long for it :D

 

I have done this with both my volvo and my subaru. honestly, the results were better with the volvo, but not too bad with the soob.

Link to comment
Share on other sites

Where do the oil and coolant lines join the head? i think i found the oil ones but im not sure (this is on a turbo head that i have lying around,.. cracked)

 

Im considering a high comp turbo now, im gonna look at the parts car on sunday

 

I just need a rough idea of what has to be done to the motor before i whack a turbo on

Obviously crossmember, turbo exhaust, needed intake pipes, mounting brackets ect will also be needed

 

 

Thanks

 

Gannon

Link to comment
Share on other sites

it seems like a good compromise to me. the car companies always make the turbo motors just a little bit too low compression for me usualy.

 

i ran stock boost on a 9.8:1 compression geo storm 1.8, and it made for some crazy quick turbo spool.

Link to comment
Share on other sites

I'm running a SPFI block w/ turbo heads. I'm using a megasquirt to richen up the fueling under boost, and it works great so far. No pinging, no problems, without intercooling, and this is in Texas 95 degree weather with just 93 octane fuel.

 

I'm not so sure it'd be so good with the stock ECU without intercooling, but it seems to work for those who've done it.

 

The low end is far far improved, and you don't have to boost all the time just to get around. Mileage is better too.

 

I'd say..do it!

Link to comment
Share on other sites

i run a SPFI (9.5:1 comp) block with a VF2.

 

No intercooler

 

Does good so far.. Havent hit the "fuel cut" as everyone describes also (referring to people with the EA82T fuel setup)

 

coolant lines -

I tapped into the heater core lines for coolant

 

Note: Oil Supply Line may need to be lengthened if your turbo is mounted differently than stock, same with the return line

 

Oil Supply Line - theres a hole on the oilpump for the oilline, on a SPFI its got a plug in it, just take it out and run your line

 

oil return - you can figure this out yourself :P But i tapped into the oilpan

Link to comment
Share on other sites

also, on the coolant lines, if you decide to go my route with tapping into the heater core lines...

 

go with the pump side and not the return line

 

you have to "T" around... what I mean is simply by just cutting the hose in half and hooking it up wont work, the flow is reduced extremely (by the turbo, and down to a trickle!!) and will make you overheat..

 

I T'd into the heater core line twice.. basically, the flow straight through is adequate to cool (so far), and the turbo gets adequate cooling (so far :D)

Link to comment
Share on other sites

Thanks guys for the info, its all useful:cool:

 

Whereabouts on the coolant lines did you tap into?

Is the plug on the oil pump where the stock turbo gets its oil?

Where is the coolant normally sourced from?

Pics would be great

 

Cheers

 

Gannon

Link to comment
Share on other sites

on a stock turbo unit the drain plug on the head is the water line for the turbo, the return line goes into the intake. the mpfi intake is not much different than turbo but the coolant line may not be there(would have to look) as dud mentioned you can tap into the heater hoses with a tee

 

on turbos the pil line goes into the back of the head, and the oil return drains to the back of the head. if you look on th eback of the h ead you will see a flat spot that is round at the bottom, this is where the oil line will be on a turbo

 

turbo heads are the same as the mpfi heads but with the passages. same ports

you can put turbo heads on an n/a block and there you go. use turbo cams should you have a turbo top end for parts

 

aside from tapping the heads i would do the oil pump and heater hose thing

 

the plug on the oil pump is extra depending on if you have the big or small oilk pressure sending unit

Link to comment
Share on other sites

ok,i assume i can run a turbo with the mpfi cams, wont this just mean that a small amount of boosted air will flow through the head before the valve closes?

 

Can a NA ecu handle a turbo (plan on adding megasquirt in future)

 

U guys are a great source if info

 

Cheers

 

Gannon

Link to comment
Share on other sites

yeah under boost its possible you will boost past the valves, but the mpfi cams will still work to run

 

the mpfi ecu is the same as turbo, the only thing different is a pin grounded to identify it as turbo or non

Link to comment
Share on other sites

I ran a 9.5:1 shortblock under the stock turbo stuff...stock turbo manifold, heads...turbo, boost etc.. etc...for 24k miles.

 

nothing speciall....jsut crazy low eng and mid range. top end was nothing due to no timing control and crappy fuel system.

Link to comment
Share on other sites

i mean mpfi non turbo and mpfi turbo ecu is the same. 85-86 and 87 later are different though, between years and not aspiration (mechanical vs optical ignition)

 

also between ea81 turbos the ecu should be campatible with ea82 mpfi turbo or non for 85-86. oneof my projects calls for an mofi non turbo from an 87 xt with an 85 turbo intake in an 83 turbo wagon with 9.5 compression non turbo block and heads, normally aspirated

Link to comment
Share on other sites

Miles,. your last post confuses me, but the mpfi motor i am getting is an 89, so will the ecu handle boost

also,.. how much boost is bypassed with the mpfi cams?

 

My plan... 89 MPFI with Turbo fitted on, oil from oil pump plug, coolant from drain plug, oil into sump, coolant into intake

 

Anything else i have left out?

 

 

Thanks

Link to comment
Share on other sites

sounds like it will work. keep it at stock boost levels, the compression will get you off the line and the turbo willhelp it out. maybe you can have some custom cams ground or fins stock ea82 turbo cams.

 

as far as the cams go you shouldn have any problems, just what i mean by blowing past the valves is the m/s cam has more overlap which is good for scavenging, and the turbos have lest overlap because boost does the act of scavenging so to speak as far as moving air thru the engine

 

where are you running your coolant into the intake at? may i suggest the heater hose or bypass pipe as you will want volume of water flowing to keep things cool

Link to comment
Share on other sites

OK, as far as the crossmember goes, has anybody just heated it and bashed it to fit?

 

Not sure where i will run the coolant, i will have to wait till i get the engine set up first.

 

Would the stock turbo be best or would i be better getting a different one?

 

Cheers

 

Gannon

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...