1992 Miata Turbo Project

I'm in ur Honda, swappin' ur motorz
User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

1992 Miata Turbo Project

Postby saabman » Sun Mar 09, 2014 1:28 pm

So at long last I started the turbo conversion on my Miata. I had done a few prepatory tasks in the last years including a rebuilt head, Megasquirt PNP 2, and viscous LSD rear end from a 1.8 L.

I am installing a Bell Engineering Group ( BEGI) Stage 3 kit with #2 intercooler and Garett 2560 turbo.

The early steps were simply removing stuff that was no longer needed (intake, cooling pipe, header, etc) and CLEANING. Even though the car was pressure washed last year there was still quite a bit of caked on grunge.

I am going to let my pictures speak with just a bit of narrative.

The first install was a water intake reroute. The next two photo show the new spigot on the block, and the reworked route for the lower radiator hose. This is quite different from the OEM Miata lower coolant route. The brass spigot is the connection for the turbo water return.

Image

Here is the lower radiator piping going to the spigot above. You will notice I don't have a PS pump but rather the OEM Miata manual steering tensioner. I have to build some spacers to move it out from the bloc about 1/8 inch. As is it makes contact with the spigot and crowds the brass water return.

Image

I did not opt for the full coolant re-route (which move the thermostat to the back of the engine). The turbo plumbing offers a good balance of cost and benefit. The splice visible in the picture re-routes the return from the heater around the back of the block and to the upper radiator. Previously this pipe returned the water to lower radiator tube/engine intake.

Image

Here is the splice/adaptor in the upper radiator hose. This is where the hose described above connects routing hot water from the heater in to the top of the radiator. Think about summer driving when all the hot water from the engine is bypassed by the heater control valve. It is still really hot. Mazda sent this back in the engine without cooling it.

Image

That's all for this post (although there is more completed work)
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Sun Mar 09, 2014 2:18 pm

Continuing the saga, attention moved to vacuum booster where a slice adapter is installed to provide vacuum/boost to various things (blow off valve, boost gauge etc (this line is fed from the throttle body downstream of the throttle plate. Just to the right of the aluminum adapter body is the inline check valve. This is a very stiff line and it was a tight fit to get this installed. Steve D. helped with this splice and the top radiator tube splice. Many thanks.

Image

The turbo sits in the middle of the block (for and aft), but it will still radiate a fair amount of heat back towards the firewall. There is an aluminum shield that will get installed to help block the heat, but the rubber coolant lines get some special attention.

Image
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Sun Mar 09, 2014 2:31 pm

So I have to eat crow with regard to the oil return line from the Turbo. When Matt Howe described how he installed the AN fitting in the pan I was aghast. My knee jerk reaction was to source a used oil pan from Ebay with the idea of installing the fitting and then pressure washing it. But when I looked at the issue more closely, swapping the pan was a BIG job and the procedure outlined by BEGI was pretty safe. So I drilled and tapped the pan on the car.

However, where BEGI says it is hard to get a straight hole because of all the compressor lines, compressor, and brackets in the way I am anal enough to want a straight hole. So I took the compressor and it bracket off and pushed them back to the fire wall. This gave me a pretty clear shot at the side of the pan.

I painted the pan with machinist dye, and then measured and marked the SPOT. I center drilled the start of the hole and then switch to twist drills. The flutes of the drill were loaded with Vaseline. As soon as the final hole was clear of the drill, oil started slowing spilling out the hole. So the bottom of the hole is slightly below the full oil level. Tapping was uneventful. BTW, the pan is cast aluminum.

Image

Here is the fitting installed

Image

I suspect the manual steering rack made this easier than it might have otherwise been.

The oil was drained after the fitting was installed. No shavings visible. And just for good measure, I flushed the pan (through the oil drain tube) with Mineral Spirits.

Not visible in this picture but the compressor bracket and compressor sit close to but no so close to provide interference with the drain line hookup or routing.
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
eg8tuner
Posts: 1159
Joined: Wed Sep 20, 2006 12:25 pm
Location: Alfred
Contact:

Re: 1992 Miata Turbo Project

Postby eg8tuner » Sun Mar 09, 2014 7:40 pm

its go to know that i can put the return that low in the pan for my new engine. my current pan has it up near the top of the pan. it would be hard for me to get it up there with my equipment.
1996 Turbo Otter
#14 in honor of Eric
"Driving the Sonett is to driving my car as underwater tig welding on flammable gas tanks is to super gluing Popsicle sticks."~Richard
best thing I've ever heard/read

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Sun Mar 09, 2014 8:05 pm

Yeah, if the car has A/C there is no way you can go high and clear the brackets with a nice smooth sloped return line. I was worried that this low would be below the oil level, but BEGI showed they really know what they are doing with the placement guidance.
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
solfly
Posts: 4113
Joined: Sat Apr 08, 2006 11:01 pm
Location: maine
Contact:

Re: 1992 Miata Turbo Project

Postby solfly » Sun Mar 09, 2014 8:32 pm

That oil return seems really low. Is that not the sump of the pan though?
1988 Honda Civic STD Hatch

www.facebook.com/88shoe

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Sun Mar 09, 2014 11:21 pm

That is not the sump. The sump is at the end of the engine near the fire wall. As I said before, the A/C dictates the low placement. Without A/C it goes about an inch higher.
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Sun Mar 09, 2014 11:31 pm

Before mounting the turbo/manifold/downpipe, I had to mount the rest of the new exhaust (the during installation of the downpipe it must be support by the front end of the cat.

First up is a picture of old and new exhaust. Old is OEM and new is 3 inch monster. It is only possible to run this 3 inch if your 1.6 L Miata has a 1.8 rear end as it will not clear the 1.6 rear dif and drivers.

Image

Here it is mounted on the car

Image

The new downpipe is a beauty The turbo itself has an internal waste gate that feeds a 1 inch 20+ inch diverter tube. This help to insure the bypassed exhaust really escapes.

Image

And lastly, the exhaust manifold/turbo/downpipe mocked up as the will be in the car. The Garret 2560 did not look too big to me when I was handling it by itself, but in the context of the other bits it looks quite big.

Image
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
DM
Posts: 5710
Joined: Tue Nov 29, 2005 12:15 pm
Location: Freeport,ME

Re: 1992 Miata Turbo Project

Postby DM » Mon Mar 10, 2014 6:57 am

saabman wrote:So at long last I started the turbo conversion on my Miata. I had done a few prepatory tasks in the last years including a rebuilt head, Megasquirt PNP 2, and viscous LSD rear end from a 1.8 L.




That's a Torsen LSD, the viscous was 1.6L only
Dan

CKT Slingshot KT100, Frankenstein RM1 Rotax DD2, 2013 Factory 5 818S

Quote for further thought:

Winston Churchill:

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy; its inherent virtue is the equal sharing of misery...”

User avatar
Rocwandrer
Posts: 7152
Joined: Mon May 15, 2006 4:04 pm

Re: 1992 Miata Turbo Project

Postby Rocwandrer » Mon Mar 10, 2014 10:44 am

saabman wrote: Think about summer driving when all the hot water from the engine is bypassed by the heater control valve. It is still really hot. Mazda sent this back in the engine without cooling it.



I never knew that!

saabman wrote:
The turbo sits in the middle of the block (for and aft), but it will still radiate a fair amount of heat back towards the firewall. There is an aluminum shield that will get installed to help block the heat, but the rubber coolant lines get some special attention.


Indeed! Do you remember these (water filled) lines catching on fire on my miata with that same turbo and same manifold configuration? :D I recommend a metal shield spaced out from the lines a little bit, on top of the reflective fiberglass filled tape, based on personal experience with the tape being ever so slightly insufficient by itself (unless you will put a shield on the downpipe/turbo). Mine was made from a couple soda cans, the inside one crumpled to enforce an air gap, but I'm sure that is below your minimum standards of quality for this build. :D

solfly wrote:That oil return seems really low. Is that not the sump of the pan though?

He gets away with it because the turbo is a lot higher up and almost directly over the pan fitting. With less height, the pressure head increase due to being below the top of the oil in the pan is problematic. It doesn't hurt that under boost conditions, the oil will be sloshing away from the fitting... :D


How much boost are you planning to run? I'm interested to see how you handle the various intake and intercooler challenges (straight begi kit approach?).

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Mon Mar 10, 2014 10:50 am

My bad (you are correct sir), the whole point in getting the 1.8 LSD was to get a Torsen (but that was a while back). The added benefit was I could fit this exhaust.

The only thing I will modify is to get rid of the recirc blow off. This would allow me to ditch the cross tube that brings pressurized air from passenger to driver side. Megasquirt is speed density so there is no need for recirc.

12 PSI is what I was told was the limit of a stock bottom end (so that is my target). I got a big enough intercooler to go with higher pressure if I built a new motor.
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
DM
Posts: 5710
Joined: Tue Nov 29, 2005 12:15 pm
Location: Freeport,ME

Re: 1992 Miata Turbo Project

Postby DM » Mon Mar 10, 2014 2:13 pm

Ian's red Miata has that same torsen mod, 94+ brakes front and rear and a low mileage 1.8

Sounds like that thing will really scoot when it's done!
Dan

CKT Slingshot KT100, Frankenstein RM1 Rotax DD2, 2013 Factory 5 818S

Quote for further thought:

Winston Churchill:

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy; its inherent virtue is the equal sharing of misery...”

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Thu Mar 13, 2014 5:36 pm

The weather and press of work has put a damper on my progress. That said here is my next albeit short installment.

The power steering delete idler bracket interfered with the BEGI water feed pipe and water return barb on the feed pipe. I fashioned 5mm aluminum spacers to offset the bracket away from the block

Here is the bracket and you can see one of the spacers on the rightmost bolt.

Image


And here is a shot showing the improved clearance to the brass barb fitting. Before offsetting the bracket I don't think there was clearance to fit a hose over the barb.

Image

The other day Richard Nye turned me on to Stage 8 locking fasteners. I sourced some and used them to secure the manifold to the block. Thankfully the torque spec is pretty broad and this allowed me the needed rotational freedom to get the locking fingers tight against the manifold.

Image
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair

User avatar
saabman
CMC Weather Chair
Posts: 6186
Joined: Tue Apr 11, 2006 7:50 am
Location: Standish, ME
Contact:

Re: 1992 Miata Turbo Project

Postby saabman » Sun Mar 16, 2014 9:02 pm

More progress to report on. The turbo, downpipe and cat back exhaust are now all hooked together. Clearance around the downpipe looks good and so does cat clearance.

This show shows the system in all its glory

Image

My attention then moved to the intercooler and the plumbing. BEGI did a nice job of power coating all the steel pipes. They use steel as it is a better heat reducer (or so they say). The instructions call for removing the tow hooks (as the intercooler use the same mount point). Rather than do that, I crafted some spacers that sit in the tow hook, and allow the intercooler to sit flat and be well supported sitting on top of the tow hook. The intercooler sits flat despite its appearance in the picture.

Image

Here is the plumbing from the output of the turbo to the input of the intercooler. The pipe is two sections, and the one that mates with the turbo has a bunch of bends. Lots of twists and turn to get it in place. The AC lines, AC Compressor, and inner fender are the major obstacles.

Image

And lastly, this is the intercooler to throttle body. This routing was complicated by the after market CX Racing radiator. It is thicker than OEM and as a result moves the OEM fans closer to the engine. This in turn puts the throttle body down tube out of position. I was able to make adjustment to the fan supports and got everything to line up. However, I need a longer coupler. The 3 inch supplied will not bridge the gap between the pipes.

Image
Chris

1971 Saab Sonett, #97
CMC 2002-2011 A/X Chair


Return to “Project and Technical Forum”

Who is online

Users browsing this forum: No registered users and 6 guests