JV6 Miata during a pandemic

I wanted to bolt in the A/C pump before I get started on the headers.  I really had no idea where the back end of that thing was going to be relative to everything else on that side of the engine.

Lucky for me the A/C has never worked and I had it evacuated last year in prep for me to rebuild everything. So I popped off the compressor with the main hoses still attached to check fit on the J35.  I bought one of the new  A/C Miata mounts from MiniTech to bolt right up.

The Miata A/C clutch lines up pretty good with the inside 4-groove pully. I wonder if the Honda clutch should fit. Just need to try one.

  I could use the original minivan pump but its much too big for the rest of the miata size ac components.  The thermostat would just limit it to short cycles.  Same thing for the alternator, don't need more the 100 amps for the size of stereo I plan on . It would be nice to have the alternator on the passenger side, but not likely

I de-powered the steering with a simple loop of hose for the low side to the high side. While I look to see if I could use the miata pump instead of the honda setup.

I'm not really keen on the honda location at the center of the valley.  And BTW I really don't like the Miata with out power steering. It has completely lost it's toss ability and the small steering wheel means two handed steering in the parking lot. Sooo I'm looking to  rebuild the Miata pump and get it back into the car ASAP.

I flushed the rack and the rest of the steering system and re-installed it today. I did find a nice power steering cooler I had pulled from a 90's suburban awhile back and a place to stick it when I swap the engines.

It's so nice to have my power steering back. It's back to being very quick through the tight twisties.

I hated the looped line in my miata. However, after doing the full depower thats written up, i really like it. I did wind up with a slightly larger steering wheel after the r comps though, to reduce driver fatigue. It would just beat me to death at the autocross and low speed parts. 

Next time I go parts hunting I will get a spare rack and do the full mod to it and try it again later. 

Oddly enough I have one or two racks from my 88 Fiero stuff and they are fully manual from the start. It's about 2.8 turns lock to lock.  The Fiero can tell you what exactly the road feels like under the front tires through the steering wheel.

Previously I had experimented with rolling my own mufflers with a pair of 5" SuperTrapps. I have ridden with them a few weeks and have really grown to like the sound. 

Last weekend I removed them and went back to the 3" turbo muffler to see about making a receiver hitch. 

I was taking aback by the shear lack of any exhaust tone or volume. !?!?!?  

At least the stereo sounded much better.

Anyway, I'm going to try some dynamic bypassing of the turbo muffler so I can dial it in when I want the tone and also turn it off for good tunes!

While I was scrounging bits and pieces to make the receiver I uncovered some more Supertrapps from a long gone Harley and started eyeballing my exhaust tube bin for proper tube diameter.It should hang just about here:

I got one more piece to size up and I think I have enough shield gas to tack up rest for pics.

I got interrupted with exhaust fun with an issue with the charging system. Went for a ride to test out a new shift knob, and after a little bit I was getting a miss around 4000 rpm.  1st thing I thought of was the crank or cam sensor was going out. Pointed the car towards home and on the way the miss turned into a drop out above 3000 rpm.  I have a voltage meter/usb outlet in place of the cig lighter but my line sight to it is obscured by the shifter boot most of the time. When I leaned over to look at it, it was 7.9 volts at idle.  

Made it back to the house and plugged it into the charger, it took the charge no problem.  Started in on removing the alternator for load testing diagnostic.

After messing with hundreds of 70-90's chevy alternators, this is only 2nd charging system that uses the ECU as the voltage regulator.  So I find myself with a perfectly fine OEM alternator and now an ECU with a bad voltage regulator. 

So it went from a simple R&R to replace the ECU and get the VATs sorted out.

So I thought I'd try and bypass the ECU with an external variable voltage controller for the Hitachi alternator.

Well the alternator was a simple fix. Found a rebuild for cheap and R&R the old one.  I did break it down and found one of the brushes worn down to just a nub.  The ECU was fine.

I did gather parts for the JV6, a Dodge panel van 135 Amp alternator and a adjustable voltage regulator to control it. It's just a little bit bigger then the old miata one but smaller then the 155 Amp Honda unit usually seen on the mini-van.

I want to mount it low and on the passenger side, so I'm going to fab a mount for it and clear all the vtec stuff on that side.

While all the alternator stuff was out of the way I installed a remote oil filter setup I was using on my C4 Vette. The Hamburger adapter is a serial filter setup.  1st filter is a 50 um stainless screen filter to grab big stuff and the second is a 10 um paper filter. You can get larger capacity fine filters for longer change intervals. 

I used an Ebay adapter to mate up to the BP.

It's a tight fit behind the brace, but if you route the hoses straight down first the bend forward is loose enough to work.

The go over the rack right at the end of the bellows.

I made a bracket to hang it under the headlamp shelf.  The shelf is a little flimsy so it needs a little reinforcing. 

Things tuck up nice.

There is a BIG differance in the capacities! 

There is no pressure drop across this setup and I have seen an increase in pressure at the Miata gauge at idle.

It's close but still clears with the stock wheels. 

I have another screen filter half that size when the big tires come around.

I want to thank my fellow Miata dudes at Jiffy Lube. 

It's a great sensation to share a little automotive joy

Still trying to pass emissions. Dang not ready codes.

And when did battery prices go through the roof?  My replacement battery for the Miata was $176!

I wrestled with my old welder and tried to scratch tig with it.  OMG i'm not going to do that again! I got an Arc Pig starter and life got better,,, a little. I really miss my DynaStar for fine detail work like headers.  First thing I learned how to do on the 300 XMT is blow dime size holes through 16 gauge tube in a blink.

Anyway I ugly welded up some old tubing and the 4" SuperTrapps from a old bike project and restuffed the cores with a combination of the old original fiber glass matt and new stainless mesh.  With 10 discs in each muffler it is as loud as if there were no discs. And it is loud when you step on it. Loud enough to feel it in your butt like open headers, so I may try a few less discs. But its got a great tone to it.

Well I found out why it is so loud, I forgot to weld up about 2" of seams in the muffler body. Should be better when I finish welding it.

I tuned the supertrapps a little. I taped up the un-welded seams with some high heat tape and removed 6 of the 12 discs per muffler. There was a small change in loudness and a reduction in drone. 

I will drive it around a little and live with it a little more.

Up Date on the SuperTrapps.  

The stainless mesh and fiberglass packing had just a little too much drone for everyday so I swapped out the main muffler's packing with a new replacement blanket from SuperTrappp.   Disc count is 5 in the main, 4 in the secondary.  I was rewarded with a deeper sound at idle, yet it still gets on the pipe above 4000 rpm. 

I'll try it out for a while and see if it will stick!

I had a few old mechanical  gauges  on the shelf that I thought would look get in the center vent. I did have to order a 1/8 BP to 4 AN to go in the block.  Used a meter long -4 AN ss hose to connect it up for a nice quick responding gauge

I did not know I was missing a few HP's until after replacing the 19 year old oem fuel pump. 

A few days ago I jump in the miata for a nice sunny drive and no joy was had. It would not start. I quickly went through check list of "got to have to run" parts that have been replaced recently and stopped at 'fuel pump'.

Sure enough, no pump sounds coming from behind me. Got out and starting making good on my fuel upgrade plans.

The oem fuel pump would work for the Jv6, bearly. The Honda likes ~55 psi fuel pressure and almost twice the volume as the 1.8 liter.  So I just upgraded the Mazda unit for a Delphi pump made for a Honda pilot. It was about $30 cheaper then the Delphi replacement for the Mazda.

The leads to the pump were different but it was a simple spade crimp on change. Re-used the Mazda pressure regulator and was pleasantly surprised regaining that handful of lost horsepower.

Angst and other foul mood stuff!  No start again on a really nice day. Argh.  Well I certainly got fuel still, but no spark.  I had already replaced the crank sensor a few months ago, so I bet the original oem cam sensor is suspect now. 

Replaced said unit and car now starts, big forking deal, the screw head twisted off in the valve cover. Now I have to drill and tap it out.  rrrrrrrr.

I have run the Supertrapps for a handful of months now and have grown to love the sound of it. You know when the exhaust tone is right is when you have to replace it with another muffler and immediately think 1st time out, "No, that's not it".

In reply to cc454 :

Now you've got me intrigued by the possibility of fitting Vette seats to a Miata. Is the Vette seat narrow enough to work with some Miata rails and sit in a stock floor pan?

The passenger side is mounted on a simple after market miata seat lowering adapters that was re-drilled to match the C4 seat. The passenger side floor is left stock.

I also installed some 6 point harnesses. I had some regular C4 seats so I used those bottom cushion to cut the crotch belt access holes in rather then use the really nice set of sports seat cushions.

Just a little note about living with a 6 point harness full time.  It's not that bad considering the effort it took getting INTO a miata with door bars. By the time you get your butt into the seat, it's nothing to buckle up. Just plan on staying awhile because it takes 3 times the effort to get out of a miata with door bars.