Randall Cowl Intake Installation on '94 Miata

Time for a little more work on the '94. Since I got the fuel issues sorted, it's been running great. So today I installed the Randall cowl intake. It's just a carbon fiber tube that connects the factory airbox to a hole in the firewall that ingests air from the cowl area where the air is nice and cool. I bought it from Flyin' Miata and it's one of the few aftermarket intakes that actually shows a horsepower gain on the dyno. I didn't get it for the horsepower, exactly. Mainly it was just because my stock intake tube was cracked and I figured while I was replacing a part I might as well get something that could somehow be considered an upgrade. In other words, because racecar.

 

The tube.

The intake comes with a template, because you have to cut a hole in the firewall. You also have to bend the clutch hard line a little bit to get it out of the way.

Possibly the most imprecise cutting tool on earth, but it got the job done.

Two holes. Sorry for fingers in photo!

With Dremel tool, make one hole.

Touch up with paint.

Cram carbon fiber tube into place.

I found it best to loosen the airbox from its mounts to make it easier to snap the Randall onto the flange.

Driving impression: so far so good. There's a little more intake noise and my highly calibrated butt can detect a little more responsive throttle. Nothing dramatic, obviously. It's a tube.

A Small Relief

I got my M3 back from the body shop today. The work was done by Gene Perez Body Shop in Tampa and I'm perfectly happy with the work they did. They did a good job of communicating with me and provided a high level of service. It was relatively quick and painless and the other guy's insurance picked up the entire tab.

The repair total came to just over $5100. This included a new fender, bumper cover, right headlight, and some other miscellaneous bits needed to put everything back together. They blended the color in to the door and hood and it looks to me like a perfect match.

The only issue is that now the left headlight lens looks shabby compared to the new one so I've ordered a new lens for $57. I also need to replace the fog lamps because they are very road-rashed and now look very bad compared to the rest of the car, which looks brand new!

It's good to have all my toys back in the garage. It's been 3 weeks to the day since the accident. It's strange where one finds comfort. I've had some difficult times the past few weeks and these machines in my garage make me a little bit happier.

Summer Has Arrived

Now that my fuel line blues have been solved, it was great to get the car out for a drive today. It was almost 90 degrees! I also got a new iPhone 4S, so I'm enjoying using it for higher quality photos and videos for my blog. Most of the photos used on this blog have been taken with an iPhone. Some were taken with a point and shoot camera but I find the iPhone photos are more than acceptable for my purposes and especially now with the new one, the photos are quite nice.

Update to '99 Miata Head on '94 Engine - Fuel Rail Issues

I've been waiting to post this until I had a definitive solution, but if you look a couple blog posts back you'll see my car on the back of a flat bed. The issue that cropped up was the fuel lines simply let go from the fittings on the fuel rail and I couldn't get them to hold on no matter what I tried. This led me down a path of learning more than I ever wanted to know about high pressure fuel injection hose and what type of hose is proper for this installation. Maybe this was obvious to everyone else who has done the '99 head swap but in all my reading about the subject I never saw it mentioned and I did find a few posts from people who were having trouble with leaking fuel hoses.

In this photo you can see the fuel pressure regulator. When installing the '99 Miata head on the '94 block, it's necessary to use the '99 fuel rail with the '94 fuel pressure regulator (FPR) because the '99 is a returnless system, while the '94 uses a return to the fuel tank from the FPR. The '94 FPR can only be oriented one way, due to a vacuum port that has to face out. That's no problem, but it dictates the routing of the fuel hoses. You can see this one sticking straight up, and the other one sticks straight down. The '94 fuel rail has an input that has a flared end on it so the fuel hose with a clamp on it will be nice and tight. The '99 uses the newer style fittings that click into place and require a special tool to remove, so the input to the rail has NO FLARE. The '94 FPR has an output on it that is flared, and so must be a clamped connection. Being ignorant when I embarked on this project, I blithely bought the first spool of high pressure fuel hose I found online and simply clamped the hoses to the fuel rail connections and on the other end to the fuel hardlines from the tank. It worked for 2000 miles.

Here's a view of the '99 fuel rail input. This is not designed for a clamped connection. After 2000 miles (about 5 weeks) of use, the fuel hose fell off and no amount of tightening of the clamp would hold it on. Even after replacing with a new length of hose, it would not stay on. The resulting spray of fuel in the engine compartment was quite undesirable! Interestingly, the hose on the '94 FPR fitting with the flared and clamped connection was leaking too! This meant that my problem was two-fold.

After doing a bit of research, I found that there are a multitude of SAE specifications for fuel hose. There is hose designed for high pressure (injected) applications, hose designed for clamped connections, and some for connections using barbed fittings (picture below). Some hose is designed to be compatible with diesel, gasoline, and ethanol, some is not compatible with all of those. So, you really need to understand the specs and make sure you get the hose for the application. Any fuel hose you buy will comply with one of these specs, however when buying online the spec is very often not indicated and you don't know what you're going to get. The hose pictured here is the "right" hose to use in this application. The spec is SAE 30R9. It is designed for a clamped application, high pressure, and low permeability to petroleum distillates (to meet environmental regulations). The original hose I bought was SAE 30R7, which is all of that, but NOT for a clamped application. This is why it eventually let go from my FPR fitting, even though there is a flare there and the clamp was tight. On the fuel rail supply fitting it was even worse. The lack of a flare meant there was no chance of it staying put and on my second try with this hose it fell off after literally 5 minutes of running.

So here's the fix. For the '94 FPR connection, it's important to use SAE 30R9 fuel hose (Gates P/N 27085), so the clamped connections will work. For the '99 fuel rail input, the 30R9 hose is fine, but you need to make the connection with one of these. It's DORMAN part number 800-081.5. It's a nylon 5/16 inch 90 degree barbed fitting. It needs to be 90 degrees because the space under the fuel rail is very tight and a straight fitting doesn't fit. I got 5 of them from Autozone online for about $12. It was a special order item so I'm not sure if you'll find them at your local store.

Here's the assembled hose and fitting. It JUST fits in the space under the fuel rail. The connector gives a very reassuring and positive click when engaged.

This shows how I ended up routing the hoses. It had to change a bit with the 90 degree bend at the end of the supply hose. From the hard lines on the left, they both run back behind the intake manifold and then run forward right on top of the fuel rail. Finally, the supply line goes forward and makes a gentle 180 to go under the end of the fuel rail and make the supply connection. It's not ideal as I'd rather the fuel hoses were more concealed, but I had to take the route with the least sharp bends and the right approach direction to the fittings. You might find a suitable route under the intake manifold, but there's very little room to make the connection down there and I was being conservative because I needed this to be fixed!

Not What I Needed

From the department of crap that I really don't need right now: a Lexus pulled right out in front of me on my way to work two weeks ago. I had nowhere to go and not enough room to stop, so this was the result. The insurance estimate is $4600.

It actually could have been a lot worse. The airbags did not deploy. At least I'll get my front bumper freshly painted. It needed it.

So I got to ride home in a tow truck twice within 5 days time. As of this writing the M3 is still in the body shop, but should be done this week. I've been driving a Chevy Impala rental, which I have not enjoyed at all.

Flat-bed Blues

A truly rare sight! This car has not been on the back of a flatbad since 1997 when I crashed on track at Laguna Seca. I detected a strong smell of gasoline this morning when I got to work and then at lunchtime it wouldn't start at all. Investigation revealed both fuel lines to be very loose on the fittings at the fuel pressure regulator. In fact, the supply side had popped off completely! Fuel was gushing quite vigorously and creating a pretty nice puddle of gas under the car. After some attempts to replace the hoses, it became apparent that they would not stay tight no matter how hard I screwed down the clamps. These have been fine for over 2000 miles of city driving since I put the car back on the road in January, so I'm really not sure why this happened. The hoses are fine on the supply end, but at the fuel rail they won't grip the fitting at all. Very strange. I think it's just the hose I used is somehow not right so I've ordered some more 5/16" fuel injection hose and some better clamps and will redo the fuel connections.

Hella FF50 Driving Lights

This may be the worst installation write-up ever, as I pretty much didn't get any pictures of how I did the installation. It's quite straightforward, though. You just need to know how to crimp end connectors on wire and build a basic harness, as the kit doesn't come with a complete harness. It just comes with about 25 feet of wire, a relay, and a bunch of end connectors. To the kit I added an in-line fuse holder so I don't burn the car down, but most of what I needed was included with the kit. I cannibalized some nice wire loom from a harness that came with an old light set I had but never used.

I mounted the Hella FF50 lights in the mouth of the Miata, using existing holes in the bumper cover. Wiring involved installing a relay which is energized by a 12V source in the engine compartment that is hot when the ignition is on. In turn, the lights are powered by a feed directly from the main power feed at the fuse box, with a 30-amp fuse in-line (which was not included in the kit). The relay is mounted just outside the main fuse box to keep the wire runs short. I spent a lot of time tucking wires and running them through wire loom to protect from abrasion. As a result, there is very little wiring visible from the engine compartment. That's why I'm not showing a picture of it.

They come on with the ignition and are aimed very low so as not to blind other drivers. The right one is angled to the right to light side of the road.

The headlights are Cibie H4 e-code lights. The Hella driving lights are a nice compliment. I've decided I need to be able to turn them off, though, and raise the aim so they extend farther down the road. Right now they light the foreground too much, which actually hurts your ability to see farther. My main reason for installing them is to have them on during the day as daytime running lights.

Here's the light pattern from the driving lights with the headlights off. They are basically spot lights, so you can aim them exactly where you want them. There's a bit more scatter than the e-codes but as long as they aren't pointing into oncoming traffic they should be ok. Once I get the switch installed I won't use them at night unless I'm not in traffic.

Photo update.

Just a pic of the car as it sits right now. I'll be painting the hardtop soon but it won't look much different. It is going to be flat black, which should look interesting. The other outstanding tasks are installing the new Hella driving lights, the Flyin' Miata frame rail reinforcements, and rewiring the horn so it works. When I ripped out the airbag wiring, I forgot that the horn wire runs through the same harness. I'll need to locate the horn relay and run a new wire to the clockspring connector at the steering column.

Camshaft Fix and Finished Paint.

This weekend I swapped out the incorrect BP06 exhaust camshaft for the BP4W. The engine runs SO much quieter now. It virtually purrs. I'm very glad to get this sorted out because I thought for a short time that the engine overhaul had been a failure.

I can't express how good it makes me feel to not have those noisy hydraulic lifters anymore. They are a real scourge upon the owners of '90-'97 Miatas. Some cars never have a problem with them, but mine were noisy and getting worse for years.

I finished wet sanding with 1500 and 2000 grit paper, and then cut with Griot's Garage #1 polish, followed by their #2 polish and show car wax.

There are flaws in the paint, but it's still 99% better than it was and I only spent about $500 on the paint job. I like the color better than the original Mazda Classic Red. As long as it stands up over time, this is a win.

New Steering Wheel

MOMO Tuner wheel. I really like it.

Here it is in the car. The previous wheel lasted 12 years but it was time for a new one.

One of the next projects - Hella FF50 driving lights. I'll do a blog post on the installation.