Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

Carbed block in Turbo wagon without a turbo??


  • Please log in to reply
13 replies to this topic

#1 hush777

hush777

    More Subarus than Kids!

  • Members
  • 388 posts
  • Idaho

Posted 09 January 2005 - 10:39 PM

Just thinking about this.
I have an 86 carbed wagon that is not worth fixing, but the engine/trans (d/r) are good. Also have an 85 turbo wagon with a bad bearing (so the guy says).
Am thinking, to eliminate the compression issue and also give my old lady a 4x4auto which she wants (but has a lead foot so skip the turbo power) of putting the carbed block in place of the turbo block and redo the exhaust to what would be on a non turbo wagon......
Will the computer handle running things ok without the turbo?? Just in MPFI mode?

Hush

#2 [HTi]Johnson

[HTi]Johnson

    Head Trauma, inc.

  • Members
  • 1,512 posts
  • Coburg, Or.

Posted 09 January 2005 - 11:04 PM

I know people who used a carbed block in place of a turbo block. There is a risk of shiz breaking Due to the compression. But this car went 200+miles, rally-ed, and went another 250+ miles back home. No problems at all.
So why not keep the turbo?
[HTi]Johnson

#3 naru

naru

    1000+ Super USER!

  • Members
  • 1,774 posts
  • under the bridge

Posted 09 January 2005 - 11:15 PM

Just thinking about this.
I have an 86 carbed wagon that is not worth fixing, but the engine/trans (d/r) are good. Also have an 85 turbo wagon with a bad bearing (so the guy says).
Am thinking, to eliminate the compression issue and also give my old lady a 4x4auto which she wants (but has a lead foot so skip the turbo power) of putting the carbed block in place of the turbo block and redo the exhaust to what would be on a non turbo wagon......
Will the computer handle running things ok without the turbo?? Just in MPFI mode?

Hush


I think this would work fine.Swap distys too.You`ll also want to swap the transmission vacuum modulator to a non-turbo one.

#4 ShawnW

ShawnW

    Subaru Master Technician

  • Administrator
  • 12,931 posts
  • Denver, Colorado

Posted 09 January 2005 - 11:50 PM

Just don't run it very hard or you will blow the pistons into pieces.

#5 naru

naru

    1000+ Super USER!

  • Members
  • 1,774 posts
  • under the bridge

Posted 10 January 2005 - 02:09 AM

Just don't run it very hard or you will blow the pistons into pieces.


Why? No turbo.

#6 hush777

hush777

    More Subarus than Kids!

  • Members
  • 388 posts
  • Idaho

Posted 10 January 2005 - 02:39 AM

Why? No turbo.



Turbo blocks are (I think) 7.5 : 1 compression and I don't have an extra around or the resources to redo the one in the wagon right now. Carb blocks and also the rare mpfi non-turbo blocks are 9.0 : 1 so I could just change the heads out from the turbo engine and use the short block from the carb engine. That high of compression in a turbo situation will result in lots of detonation and possible engine damage... melted/cracked pistons... blown head gaskets from to much pressure.....

Hush

#7 naru

naru

    1000+ Super USER!

  • Members
  • 1,774 posts
  • under the bridge

Posted 10 January 2005 - 03:30 AM

Turbo blocks are (I think) 7.5 : 1 compression and I don't have an extra around or the resources to redo the one in the wagon right now. Carb blocks and also the rare mpfi non-turbo blocks are 9.0 : 1 so I could just change the heads out from the turbo engine and use the short block from the carb engine. That high of compression in a turbo situation will result in lots of detonation and possible engine damage... melted/cracked pistons... blown head gaskets from to much pressure.....

Hush


I said "Why? No turbo."(re piston destruction) not "Why no turbo?"

#8 calebz

calebz

    Andys Coupe killed my cat

  • Administrator
  • 7,547 posts
  • Tacoma

Posted 10 January 2005 - 04:05 AM

Turbo blocks are (I think) 7.5 : 1 compression and I don't have an extra around or the resources to redo the one in the wagon right now. Carb blocks and also the rare mpfi non-turbo blocks are 9.0 : 1 so I could just change the heads out from the turbo engine and use the short block from the carb engine. That high of compression in a turbo situation will result in lots of detonation and possible engine damage... melted/cracked pistons... blown head gaskets from to much pressure.....

Hush

So I guess I'm in trouble with my carb shortblocked turbo motor with the TD04 on it eh?

BTW, Turbo motors are 7.7:1. I was under the impression that the Carb motor was 8.5:1. Anyone here with an 87 FSM that could give me a definite answer? My 88 and 89 FSMs don't have any carb info.

#9 canajun2eh

canajun2eh

    USMB is life!

  • Members
  • 222 posts
  • Ottawa, ON, Canada

Posted 10 January 2005 - 05:50 AM

Carb specs are the same as SPFI, compression-wise.

I don't see any reason why you couldn't use a short block from a carbed engine, mated to the MPFI/Turbo gear from your defunct engine. I agree with you, that you shouldn't run into any longevity issues if you disable the turbo.

Better still: Remove the turbo completely. That would improve exhaust flow, giving you a tiny bit more power. As near as I can tell, the turbo doesn't provide any meaningful input to the ECU. The ECU would just see zero boost.

#10 hush777

hush777

    More Subarus than Kids!

  • Members
  • 388 posts
  • Idaho

Posted 10 January 2005 - 11:58 AM

I said "Why? No turbo."(re piston destruction) not "Why no turbo?"


Just no turbo short block around right now....
Hush

#11 calebz

calebz

    Andys Coupe killed my cat

  • Administrator
  • 7,547 posts
  • Tacoma

Posted 10 January 2005 - 12:40 PM

Carb specs are the same as SPFI, compression-wise.


That doesn't make any sense.. My books say SPFI is 9.5:1
Pistons between carb and SPFI are different part numbers
EA82 CR is based completely on piston shape.

Does anyone out the have an 87 FSM with carb info in it?

#12 WoodsWagon

WoodsWagon

    Formerly 91Loyale

  • Members
  • 3,945 posts
  • NH

Posted 03 May 2005 - 09:46 PM

I was under the impression that the turbo were the lowest compression engines, the SPFI were the highest at 9.5:1 and the carb's fell in the middle.
Will the mpfi turbo intake manifold bolt up the the cab heads though?

#13 85Sub4WD

85Sub4WD

    EA82 Junkie

  • Members
  • 1,244 posts
  • Raleigh NC/Charlotte NC

Posted 03 May 2005 - 11:13 PM

I was under the impression that the turbo were the lowest compression engines, the SPFI were the highest at 9.5:1 and the carb's fell in the middle.
Will the mpfi turbo intake manifold bolt up the the cab heads though?

SPFI (1989 FSM) - 9.5:1 (domed - so I'm told)
Carb/MPFI N/A (1985 FSM) - 9.0:1
Turbo (both) - 7.7:1

MPFI turbo intake will NOT bolt to carb heads - either need to run carb manifold or swap heads

#14 wagonist

wagonist

    User Awaiting Email Confirmation

  • Members
  • 438 posts
  • Sydney, Australia

Posted 03 May 2005 - 11:47 PM

If you use the block & bottom end, exhaust from the carb, with the heads, inlet manifold, air flow meter from the turbo should be ok.

You'll have to block the water & oil pipes to & from the turbo though.

don't know how the mapping of the turbo ECU will react to higher revs but no boost reading. Might go into a "limp" mode.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users