planned miata project

[minispeed]

My first fill up got me 6.1l/100km, 38.6mpg. 371km, about 1/3 city, 2/3 highway at 95km/hr. The highway revs at 3200rpm too so that's probably hurting the economy.

I'm pretty happy with that and it has me thinking that maybe 5.0 (47) is achievable.

[minispeed]

I had a busy weekend working on the car. First off my second tank, not as good at 6.33l/100 which involved 100km of stop and go rush hour vs the previous tanks 50, and also more city driving this tank.

I started my work on the car with trying to adjust a noisy belt which started a chain of very annoying events. The power steering belt was removed to test the econo benefit from that. That was easy enough, but the alt/water pump belt was the one making the noise. I turned the adjuster and snap, bolt broke off. Easy enough to fix though so I went to turn the bolt that holds the adjuster on.... snap.... ok so now I have to take the alternator off and drill out that snapped bolt so the bottom bolt has to come off. Can anyone guess what happened? Yes, snap... So I can't get a drill in that space so I have to use the dremil to drill out that snapped bolt which would be fine except my dremil breaks....

So I borrowed my dads, drilled it out, got the belt back on and as tight as possible, a little better but still a small noise from the belt so I figure now I get to do the fun stuff.

Oil change with Mobil 1 0w20.

I added LED stripes for the day time running lights DRL. I'll be using all LED for the lighting with the exception of the front turn signals so that less energy is used during EOC.



I also removed the stock DRL/turn signal and drilled a new hole in an unused side portion of the light. I then added some H3 lights inside the spot that use to be the DRL/turn signal to use as headlights and avoid the aero hit of the pop ups.

I wired these up to come on with the parking lights so I can turn them on for night driving but still use the pop up low and high beams if I ever need the full lighting system. I will also be adding 50w HIDs in 4300k to the system. I ordered them after trying out just one of the lights and thinking it was a little too low, but after both were hooked up I was starting to think it might be enough.



Next came the front grill block. I went to the local dollar store and picked up some coroplast garage sale signs, $1.25 each. They also had some blue duct tape that looked really close to the miata blue. I bought that only thinking it would be for the passenger side mirror holes but then decided to use it on the coroplast instead of painting that black. I sized the hole in the middle so that in the winter I can simply turn the license plate bracket upside down and lower the plate to block it.



Next I turned my attention to the front wheels, a well know miata aerodynamic nightmare. I ran out of tape so only covered one. I will be going and getting some steel L brackets from the home depot tomorrow to hold the sides in against the high winds.



And with the left over coroplast I started on an under tray extension as the miata has what looks to be a pretty decent undertray already. This is a really horrible picture, I should have got it from the side to show how the corners have been fully filled prior to the front wheels.



Now I'm very excited to see how I can do on my next fill up. I will probably then re hook up the power steering to see exactly how much I can attribute to that mod.

[ChopsQube]

Any updates on your '93 project?

I've got a '91 BRG that I've been working on for better economy as well. A few things you may want to consider doing later down the road that truly help improve mpg's...

* An aftermarket front spoiler (lip) as they call them. I thought about getting the stock R Package lip, but decided on the Garage Vary lip instead as it's bigger, effectively getting the front of the car closer to the ground. I haven't measured it, but if I had to guess, I'd say the bottom of the lip is roughly 3" off the ground.

* Lowering the car about an inch to inch and a half, either with slip-on adjustable spring perches or full coilovers which I have. Measuring from the center of the hub to the wheel well, I'm sitting at 12.25" front and 12.50" rear.

* A free flowing exhaust system including NOT a 4-1 header but a 4-2-1 header as they are better for low to midrange power. A free flowing cat and muffler as well, all 2.25". I find this to be a great combo to the stock intake.

* Shave as much as weight as you see fit. So far, I've removed 135 lbs from my Miata and plan to remove a little more by deleting the power steering. I'll elaborate more on the weight shaving if there's any interest.

* I haven't done this yet, but I plan to in the near future, which is do a small cutout on the rear bumper. It traps quite a bit of air back there like a parachute, so trimming a few inches off of it will reduce this drag.

* Get a good 4-wheel alignment! I have aftermarket 15x7 (14.7 lbs) wheels with 205/50-15 performance tires with a fairly aggressive alignment and actually saw an increase in my mpg's after the alignment.

I've done all of the above except for the power steering delete and rear bumper cutout. All of this allowed me to achieve 30mpg keeping up with traffic (between 75-80mph). In complete stock form I could only manage 31mpg doing a constant 60mph, or about 25-26mpg at 75-80mph.

Now, doing 60mph and some hypermiling, I've done a best of 37.8mpg on my last tank, managing 393 miles to that tank. I'm still "feeling out" the car as far as hypermiling is concerned, figuring out optimum shift points and acceleration rates. So with every tank, I'm increasing my mileage a bit more. I'm sure I'll see over 400 miles on this tank.

BTW, I travel 112 miles every day, 100 miles on the highway at 60mph and the other 12 miles in town between 25-45mph. In town, I can actually coast nearly half of that. While on the highway, I only coast on the downsides of hills and overpasses. I have yet to do any real Pulse & Glide as I can't see how that's going to help me on the highway, not to mention there always seems to be too much traffic to attempt it.

Anyway, here's a pic of my little pride and joy!




One more thing, I too have replaced ALL of my exterior lighting with LED's, minus the headlights of course. I even converted my left backup light to a fog light with a high-output LED.

[Sporty Modder]

Looks like a good start. Looking foward to seeing more.

[minispeed]

Originally Posted by ChopsQube

Any updates on your '93 project?

I've got a '91 BRG that I've been working on for better economy as well. A few things you may want to consider doing later down the road that truly help improve mpg's...

* An aftermarket front spoiler (lip) as they call them. I thought about getting the stock R Package lip, but decided on the Garage Vary lip instead as it's bigger, effectively getting the front of the car closer to the ground. I haven't measured it, but if I had to guess, I'd say the bottom of the lip is roughly 3" off the ground.

* Lowering the car about an inch to inch and a half, either with slip-on adjustable spring perches or full coilovers which I have. Measuring from the center of the hub to the wheel well, I'm sitting at 12.25" front and 12.50" rear.

* A free flowing exhaust system including NOT a 4-1 header but a 4-2-1 header as they are better for low to midrange power. A free flowing cat and muffler as well, all 2.25". I find this to be a great combo to the stock intake.

* Shave as much as weight as you see fit. So far, I've removed 135 lbs from my Miata and plan to remove a little more by deleting the power steering. I'll elaborate more on the weight shaving if there's any interest.

* I haven't done this yet, but I plan to in the near future, which is do a small cutout on the rear bumper. It traps quite a bit of air back there like a parachute, so trimming a few inches off of it will reduce this drag.

* Get a good 4-wheel alignment! I have aftermarket 15x7 (14.7 lbs) wheels with 205/50-15 performance tires with a fairly aggressive alignment and actually saw an increase in my mpg's after the alignment.

I've done all of the above except for the power steering delete and rear bumper cutout. All of this allowed me to achieve 30mpg keeping up with traffic (between 75-80mph). In complete stock form I could only manage 31mpg doing a constant 60mph, or about 25-26mpg at 75-80mph.

Now, doing 60mph and some hypermiling, I've done a best of 37.8mpg on my last tank, managing 393 miles to that tank. I'm still "feeling out" the car as far as hypermiling is concerned, figuring out optimum shift points and acceleration rates. So with every tank, I'm increasing my mileage a bit more. I'm sure I'll see over 400 miles on this tank.

BTW, I travel 112 miles every day, 100 miles on the highway at 60mph and the other 12 miles in town between 25-45mph. In town, I can actually coast nearly half of that. While on the highway, I only coast on the downsides of hills and overpasses. I have yet to do any real Pulse & Glide as I can't see how that's going to help me on the highway, not to mention there always seems to be too much traffic to attempt it.

Anyway, here's a pic of my little pride and joy!




One more thing, I too have replaced ALL of my exterior lighting with LED's, minus the headlights of course. I even converted my left backup light to a fog light with a high-output LED.

Not much to update as on my last drive the alt belt broke and I got towed home. Then I left for 3 weeks training in BC so no driving.

I've been thinking of a front lip for a while. I'll probably end up making one out of garden edging. I wanted to get the full front under tray done first, see what improvement that made as the front lip increases the cda, it's only beneficial because the miata underbody is very poor. Also since I will be winter driving the car the lower suspension and an expensive lower front lip are not the best combinations for me. I also don't want to do suspension work because the car hasn't had many kms since the alignment. The cost to lower and re allign will never be recovered by the FE improvements I think I'd see. I also don't want to put any money into the exhaust system.

I may start the rear bumper with drilling some holes and/or covering the bottom with coroplast. I'd rather test that for the small cost first before cutting a lot out.

I was also thinking of getting taller tires, stock being 185/60/14 I have heard that 185/70/14 has been used, that should drop 400 or so RPM from the highway cruising speed.

Also to update the full grill block it caused the temp to rise too much at highway speed on a 15degree Celsius day even though it had been fine at the low city revs of 2000rpm and below.

[ChopsQube]

Wow. Just about all of my suggestions shot right down.

Just an FYI, I have kept a fuel log ever since I got the car in Jan 2011 via Gas Cubby on my iPhone. With everything that I've done to this car over that time, I have seen constant improvements with every modification made.

Also, adding the lip spoiler does NOT add to cdA, it adds to the frontal area. But when the car got lowered, that frontal area also got reduced slightly. Due to the installation of the GV lip spoiler, it greatly reduced the air flowing under the car, thus reducing cdA a bit as well.

But anyway...

[minispeed]

Originally Posted by ChopsQube

Wow. Just about all of my suggestions shot right down.

Just an FYI, I have kept a fuel log ever since I got the car in Jan 2011 via Gas Cubby on my iPhone. With everything that I've done to this car over that time, I have seen constant improvements with every modification made.

Also, adding the lip spoiler does NOT add to cdA, it adds to the frontal area. But when the car got lowered, that frontal area also got reduced slightly. Due to the installation of the GV lip spoiler, it greatly reduced the air flowing under the car, thus reducing cdA a bit as well.

But anyway...

Im sorry I didnt mean it to sound like I was shooting down your ideas, I agree with all of them I just wanted to say how I don't have any money to put into the car.

[AntiochOG]

Fellow Miata owner here looking forward to future updates.

[minispeed]

Originally Posted by AntiochOG

Fellow Miata owner here looking forward to future updates.

The next big update will be fitting 195 70 14. Since the car revs so high at highway cruise I hope that will improve my mpg. It should also allow longer EOC, also the 155s only have a 34 psi max and I've been running them at 38. They tend to leak put back to 34 but not much lower. I hope that the tire spats will compensate for the 4cm per tire.

[California98Civic]

Originally Posted by minispeed

The next big update will be fitting 195 70 14. Since the car revs so high at highway cruise I hope that will improve my mpg. It should also allow longer EOC, also the 155s only have a 34 psi max and I've been running them at 38. They tend to leak put back to 34 but not much lower. I hope that the tire spats will compensate for the 4cm per tire.

I can see going for bigger diameter in these tires, but you might trade some of the FE gains from RPM reductions at highway speeds for FE losses due to wider and heavier tires.