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Author Topic: Re-clocking the OEM turbo  (Read 10937 times)
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'95MSM
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Posts: 6076


Turbo clocked downward, new i/c plumbing


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« on: October 19, 2010, 09:11:13 PM »

(These instructions are also valid for any turbo upgrade that re-uses the original compressor housing with a higher output compressor wheel.)

The OEM IHI has 5 fasteners unevenly spaced around the compressor cover.  With that arrangement, there are no alternative positions for the housing that do not require drilling new fastener holes.  Also, since there are only two fasteners with the correct spacing to hold the wastegate can assembly to the turbo, re-clocking requires new fasteners for the wastegate assembly that don’t go all the way through the compressor cover.

Standard compressor outlet orientation vs re-clocked (downward firing):


Remove the 5 torx-head screws.  You can let the wastegate can dangle by the actuator arm, or you can remove the clip and set the assembly aside.  (The wastegate can in the pictures is not the OEM item, but it mounts the same way.)  The compressor cover is sealed to the compressor base with RTV.  Slip a screwdriver between the compressor discharge and the base, use it like a lever and pop the cover off.  Be careful not to gouge the compressor base as you do this.

Clean all of the RTV off of both surfaces.

You will notice the base has a relief cut to clear the wastegate can.  Installing the compressor cover in any orientation that covers the relief cut simply won’t work, so the discharge must move to 6:00 or further.  

With the cover re-oriented, the heads of the screws that hold the wastegate can to the turbo will now be underneath the lip of the compressor cover.  My solution is to use a countersink bit to bevel the hole in the compressor base so that the new countersunk screw heads will fit under the compressor cover:


Countersink the screw holes until the head of the new screws is flush.  A hand-held drill motor will work just fine for this.  Install the wastegate can to the compressor base with the new screws.  These screws can become difficult to remove with age.  Don’t use Loctite here.  I recommend using stainless steel screws for this.  The female hex can rust and weaken over time if a normal steel screw is used.

Orient the compressor cover to your liking and mark the compressor base for new screw holes.  Drill the holes to 11/64” and tap with the 5mm x .8mm tap. 
Option: The back of the compressor base is fairly square to the fasteners, so if you doubt your ability to make strong threads in the compressor base, you can use longer screws and locknuts.  This is the “no-tap” method mentioned in the tools and parts required lists.  Drill 7/32” holes instead of 11/64”.

Clean the base and compressor housing.

Run a fine bead of RTV around the sealing ring at the perimeter of the housing, install the housing and tighten the fasteners.  More RTV = greater clearance between the impeller and housing and less air pumped, so don’t slather it on.  If you drilled and tapped the holes, use Loctite when you reinstall the Torx screws.  If you bought longer screws and locknuts, the locknuts should be sufficient.

Tools you will need not found in every toolbox:
T20 Torx driver
Countersinking bit at least 3/8” diameter
11/64” drill bit (or 7/32” drill if using no-tap method)
5mm x .8mm tap & handle (not required if you use longer screws w/ locknuts)

Parts list:
2 pcs - 5mm x .8 countersunk screws approx ½” long, stainless recommended
Hi-temp RTV
Blue Locktite (not needed if you use longer screws & lock nuts)
Optionally, 5 pcs – 5mm x .8mm socket or button-head screws at least ¾” long (this is the no-tap method)

  
« Last Edit: October 19, 2010, 09:16:09 PM by '95MSM » Logged

'05 running gear + '95 body
3.63 ring & pinion FM content: Blouch compressor mod, FM-Link, i/c & no-MAF intake.   BEGi: Stainless SGDP w/ metal core performance cat.   Custom stuff: Compressor clocked downward w/ new i/c pipe, big radius throttle elbow, 2.5" mid-pipe w/ Hushpower II, dual 2" axle-back w/ open Supertrapps, Toyota 4 pc cop ignition

245.2 whp on default FM-Link maps (with OEM midpipe)
'95MSM
Fifth Gear
*****
Posts: 6076


Turbo clocked downward, new i/c plumbing


WWW
« Reply #1 on: November 05, 2010, 04:48:50 AM »

Mr Hyde & I were discussing the possibility of re-clocking the turbo on the car.  It really isn't practical, but if someone bet me $500 that I couldn't do it, I might take that wager. 

The more important part of the discussion was his concern about getting the compressor cover lined up correctly over the compressor impellor.  The compressor cover is aligned by the ring visibile in pics 3 and 4.  This is a non-issue, but I didn't cover it at all in the instructions.
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'05 running gear + '95 body
3.63 ring & pinion FM content: Blouch compressor mod, FM-Link, i/c & no-MAF intake.   BEGi: Stainless SGDP w/ metal core performance cat.   Custom stuff: Compressor clocked downward w/ new i/c pipe, big radius throttle elbow, 2.5" mid-pipe w/ Hushpower II, dual 2" axle-back w/ open Supertrapps, Toyota 4 pc cop ignition

245.2 whp on default FM-Link maps (with OEM midpipe)
mr_hyde
Global Moderator
Fifth Gear
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Posts: 7213


Midlife Crisis on Wheels!


« Reply #2 on: February 07, 2013, 08:08:09 AM »

I discovered one small addendum to the process '95MSM forgot among the 100,000 steps he took to create the MSM transformation.  With the outlet clocked downward, it interferes with the neck for the water pump inlet at the lower radiator hose.  A few minutes with a sawzall fixes the problem.  We checked '95MSM the other day and sure enough, this was done on his too.  The rough cast does an adequate job of holding hose on with a good clamp.  Here are some pictures of the process.

Stock piece almost cut:


Contact without modification:


The shorted water inlet:
« Last Edit: October 17, 2016, 04:19:16 AM by mr_hyde » Logged

2005 Black Mica #290 8/27/04 w/Factory Hard Top
BEGi Intake, FM Downpipe.  Nice and calm with an edge...

1990 Red - MSM Drivetrain, Adaptronic EMS, Xida 700/400, 15x9 6uls, Full Cage, SGDP w/80mm Corksport exhaust, ~260whp @ 15psi on Forged Rods.  bow2
Build Thread: http://www.mazda-speed.com/forum2/index.php/topic,24668.0.html

2000 BMW M5 - The Falcon - Daily Driver  reddevil

2003 E350 7.3 Powerstroke Ambulance for towing '90MSM to play dates.

1991 BRG - Daughter's daily driver.
mr_hyde
Global Moderator
Fifth Gear
*****
Posts: 7213


Midlife Crisis on Wheels!


« Reply #3 on: March 04, 2013, 08:11:51 AM »

This image shows the lower radiator hose that will clear the reclocked turbo.  It would interfere with the AC compressor if it were installed on my car so you will need to source a different solution in a fully trimmed street car.  It's a Gates belt #22339.  The guy at the parts counter said is was from a Honda but didn't have any other details.  It is a bit longer at each end and needs to be trimmed.  PM me if you have anything to add to this topic and I will unlock it for you.

« Last Edit: October 17, 2016, 04:19:29 AM by mr_hyde » Logged

2005 Black Mica #290 8/27/04 w/Factory Hard Top
BEGi Intake, FM Downpipe.  Nice and calm with an edge...

1990 Red - MSM Drivetrain, Adaptronic EMS, Xida 700/400, 15x9 6uls, Full Cage, SGDP w/80mm Corksport exhaust, ~260whp @ 15psi on Forged Rods.  bow2
Build Thread: http://www.mazda-speed.com/forum2/index.php/topic,24668.0.html

2000 BMW M5 - The Falcon - Daily Driver  reddevil

2003 E350 7.3 Powerstroke Ambulance for towing '90MSM to play dates.

1991 BRG - Daughter's daily driver.
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