planned miata project

[minispeed]

Hi all,

I finally took the plunge and joined this site after using it as a reference several times. About a year ago I got a 2006 prius and started hypermilling, at first my avg tanks were about 5.0l/100km but I soon got that down to 4.4 and then by the end of the summer I was getting some 3.9 tanks. The best sustained period I had was 3.4 for about 70km but I couldn't keep that up for the whole tank. I did a few modifications including: stubby antenna, motorcycle side view mirrors, top grill block (added a lower block for winter too), lip spoiler at the trunk edge as my version had the smaller spoiler, rear wiper delete (summer only), LRR XI2 winter tires (which actually improved vs the non LRR falken tires). So far my lifetime avg is 4.88 for 19369km, winter tanks tend to be around 5.1-5.4 and my worst where I tried to drive moderately aggressive was 6.18.

I love my prius, I even convinced my dad to get a new prius V which is funny because my last car was a Saab 95 wagon and he bought one for my mom a few months after I got one. However with our first child on the way the wife and I decided she should drive the prius due to the higher seating and easier loading hatchback (for the stroller). Since we have a miata that hardly ever gets driven I will use that as my work commuter and we will turn in her lease to save money for the eventual day where we need to haul two kids + and I get my prius back and hope to convince her the highlander hybrid is the best car for her.

So with all the fun I've been having saving gas I've started to think of some planned projects for the miata. It's a 93, 1.6l 5spd with 195/60/14 performance Hankook RS2 tires, just purchased a hard top, no AC.

Planned mods are:

• Skinnier tires, looking at fitting 155/80/13 on steel wheels and if I find they handle well enough then getting Honda VX rims. If they don't handle well enough then 175/65/14 on the stock 12lb miata rims. - Fitted 155/80/13, 60% tread for $50 on steel rims, great deal off kijiji
• air dam - one of the miata problem areas is the exposed front tires which I'll have to address
• skid plate/undercarrage Coroplast extension to stock undertray
• motorcycle mirrors - Complete, no passenger side mirror
• tire spats - I'm thinking about mounting to the suspension arms to get them really low integrated to the undertray, coroplast so it's low and if it hits it won't cause any damage
• diffuser - I don't think this will be easily accomplished
• kammback
• projector HID lights inside turn signals (i'll keep the pop up head lights for legality but use the projector lights in the city) H3 (non projector) lights plus LED DRL
• possible alternator disconnect switch
• de power steering rack belt removed, if it's a good enough benefit I'll loop the lines and remove the pump. I may even remove the rack and convert it to a manual (flyin miata for details)
• grill block (partial) complete
• ignition advance (this is very easy on the miata and I already did 8 degrees I think, I'll try a few increments on the various fuel grades to see which is best. If I can use premium at a cost neutral level I will because we can get 0% alcohol premium at shell.
• maybe rear wheel skirts
• max tire pressure - 38psi
• warm air intake - this is very easy since there is already a cone intake I'll put some pipe from the exhaust side over to the cone - complete, removed the heat shield on the header and supported the cone intake right over top
• 0w20 engine oil and a change of trans and diff oil too (haven't looked into what type yet for them) mobil 1 engine oil, don't think I'll do the trans/diff as the cost would probably not be recovered
• vac gauge
• I'll try a single wiper arm but may just go with 2in smaller drivers, 3in smaller passenger side went with 2in smaller drivers, 3in smaller pass side
• stubby radio antenna

and that's the starting point.... I havn't driven the car for normal commutes in a few years but when I was younger and avg about 140km highway I was getting 9.5 and found that by slowing down to 110 I could avg high 8s. Based on fueleconomy.gov the avg for all years of 1.6l cars is 7.9 so I'll be shooting for 6.9 pre major mods and I would be very happy if I could get it down to 5.0 but realisticly I think 5.9 may be the lower limit.

[Frank Lee]

Nice job on the mods. Check out the "Physicist" thread... I might add, I was a 6'4" teenager with one sister and the biggest car the folks had at the time was a VW Rabbit and it worked just fine.

[California98Civic]

This list is very close to the list for my car in most respects, so I like. But you should have a better opportunity than me for a Kammback because your Miata is convertible. Couldn't you build a nicely curved and tapered top? It could come off as easily as the stock hardtop, but have some of the ideal aero lines often discussed on this site. And congrats of the new child too! But I have to agree with Frank Lee too... my wife and I got buy with this two door coupe when our daughter was a baby... and I remember epic road trips with my two brother, my mom, our dog and cargo in a 1975 VW Bug. It can be done!

[minispeed]

I'm 6'4" too so the miata is a tight fit but very comfy once inside. My first car (which I still have but it's a race car now) is an original mini. So I'm quite use to making small cars work.

I want to build the kammback onto the hard top for a few reasons. I already know from racers that the stock hard top improves aero, they say it's good for at least 7mph on straight long sections of tracks. It's weather tight, I won't find in the dead of winter that it leaks and I don't have an indoor area to work on cars. Build time will be reduced a lot Safety, I know the stock hard top is on tight and will not fly off. In the event that part or all of my kammback comes off it will be a much smaller and less dangerous event. I think that it will look a lot better and cleaner with the hard top. And the most important, body flex, the miata is famous for this, and my year (the lightest) has the most. I'll probably add a roll bar if I can, but before that any full kammback from the windshield back is likely to break or leak due to the normal everyday flexing of the chassis.

Since it's a convertible with no AC in July and Aug I'll probably end up going back to the soft top and I want something that comes off easily and still leaves the mounts for the soft top.

The kammback is also planned to be for utility. The first one I'll probably do coroplast for testing but eventually I want to use plexiglass with a higher back, remove the trunk lid and have the back section hinged to add trunk volume. I figure the old trunk seals will give me a place to bolt/screw to that can be hidden and returned to stock. I'd rather spend my time perfecting this than the fit and seal at the front of the roof.

[minispeed]

Thanks to kijiji I found some 155/80/15 tires, 70% front and 50% rear for $50 so I drove and picked them up today. Since the miata has 14s and people say most 13s fit I was glad to try it out with a cheap set. They fit weel, not much clearance with the brakes but enough. One downside is the max psi, only 34!!! So I pumped them up to 37.5 front and 37 rear. I figure on a 2200lb car that it's probably enough.

Here's an overview of the car, a shot showing the amount of tire that sticks out past the front bumper and a comparison of the rear view when one side was changed.

.....and the pics will be posted after 5 posts....

I still haven't sold the wifes car and haven't insured the miata yet but I can't wait to drive it, but with gas up at $1.30/L now I'll miss the prius.

[minispeed]

[Tango Charlie]

I'm diggin' the Superman color scheme.

Welcome to EM!

[minispeed]

Got my miata on the road since I needed to loan the prius to my mom as her car broke down. I started a few projects, put the motorcycle mirror on the drivers side which needed to be done since the stock mirror had rusted out and wouldn't stay in the position it was adjusted too. Also added a roof spoiler. I was thinking it would probably work better up on the roof vs the glass but since I want to vinyl wrap the roof I chose to put it on the glass.

[RunningStrong]

Have you considered losing the windscreen, going for a partial windscreen and waterproofing the passenger side while suiting up yourself?

Too hardcore?

[minispeed]

Originally Posted by RunningStrong

Have you considered losing the windscreen, going for a partial windscreen and waterproofing the passenger side while suiting up yourself?

Too hardcore?

Yes, too hardcore, the car has to offer me daily commute including Ontario winters.