Maniac0301
Maniac0301 Reader
5/17/18 11:35 p.m.

I have my Rallycross '87 MR2 that I've been thinking about adding boost to.  I was going to go turbo and I have hanging around a couple used turbos of appropriate size that I can fab something together.   I started thinking about packaging of the unit and one thing that keeps coming to mind is the space under the intake manifold from the removed A/C Compressor.   

So I have a fairly large area made clear by the removal of a pump designed to be run off the crank pully.  Seems kind of nice to fill that up with a supercharger.   So I need boost levels to be low as I'm not building the bottom end.  I figure 5-6psi.   Any recommendations on what to look for as far as an extremely budget friendly start?  Junkyard boost would be nice for it cheapness but I've also been thinking about a used Miata supercharging kit since the engine displacement and desired boost levels are about the same.   

Any thoughts?  I like the idea in Rallycross of the instant response and I'm not looking to ever really surpass 200ish HP.   If I pick up a used Miata kit I expect the compressor to be near toast how hard and how expensive is a rebuild for it?

Trackmouse
Trackmouse UltraDork
5/17/18 11:52 p.m.
Fitzauto
Fitzauto Dork
5/18/18 2:45 a.m.

Swapping in the stuff from the GZE is probably the easy way to go. Im running one in my ae86 autocross car and with a bigger crank pulley and intercooler im around ~165whp

John Welsh
John Welsh Mod Squad
5/18/18 3:16 a.m.

I sold my MR2 SC back in 2004. Even at that time, 14 years ago, it was hard to find SC axle half shafts. 

The SC came with a stronger cv/axle to accommodate the additional power. These shafts were the desire of anyone who turbocharged or upgraded the power of their NA MR2. 

I would try to source these axles first. 

Brotus7
Brotus7 HalfDork
5/18/18 6:03 a.m.

I also had a 4AGZE swapped MR2 that I sold back in 2012.  The JDM swap is the easy button for more power, and I opted to keep the stock NA C52 due to axle availability.  I autocrossed it for a few years on R comps and never broke an axle, but did break plenty of other stuff.

If you go ahead with the C52, be sure to strengthen the front center motor mount.  I also kept eating aheel bearings.  I kinda miss the blower whine.

Tyler H
Tyler H UltraDork
5/18/18 8:32 a.m.
John Welsh said:

I sold my MR2 SC back in 2004. Even at that time, 14 years ago, it was hard to find SC axle half shafts. 

The SC came with a stronger cv/axle to accommodate the additional power. These shafts were the desire of anyone who turbocharged or upgraded the power of their NA MR2. 

I would try to source these axles first. 

I'd do a V6 or even a 2.2 5SFE swap for down low torque and less mechanical complexity.   You can mate SW20 MR2 half shafts to 88-91 Camry V6 5spd outer CV joints, which will fit the NA Mk1 MR2 hub splines.  (Camry V6 axle is in stock right now for a whopping $30 at Rockauto.)  This assumes you are using an E153 transmission.  

I know this because, yes --  4AGZE axles are nigh unobtanium.  And if you do find them, you'll need the SC hubs/uprights to go along with them.

oldeskewltoy
oldeskewltoy UltraDork
5/19/18 7:12 p.m.

4AGZE I built for a client last year...... no budget concerns.......

 

Fitzauto
Fitzauto Dork
5/19/18 9:50 p.m.

In reply to oldeskewltoy :

Is that on the sc12?

oldeskewltoy
oldeskewltoy UltraDork
6/8/18 6:28 p.m.
Fitzauto said:

In reply to oldeskewltoy :

Is that on the sc12?

yes....  that was the one parameter I built this around.  Client wanted 200whp from SC12 4AGZE

GIRTHQUAKE
GIRTHQUAKE New Reader
6/8/18 6:57 p.m.

Over 200HP out of a 4A? Holy crap OST, you've got SKILLS... and a fat wallet to help laugh! Hope the owner's happy.

Maniac,

Hey, I own an AW11 too and I have a little advice from posting on mr2.com. IF you're dead-set on the supercharger you will likely need to go for a newer mercedes unit instead of the SC12, as the fandom around the GZE still doesn't have any good way of fixing or rebuilding the roots-style SC12, and the company (Ogura) has rebuffed several who have asked for kits. IF you want to try to do something on the cheap, go for a different supercharger manufacturer, snag a GZE ECU, and message Yoshimitsuspeed at Matrix Garage for more advice. You'll likely need an AFM, bigger injectors, MAYBE a cooler spark plug, and intercooler...

 

hhaase
hhaase HalfDork
6/9/18 11:51 a.m.

Wait,  your ac compressor was under the intake?  If there’s a way to mount something else crank driven under the intake im all ears.  I could fit a scavenger pump then.

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