How can I make my Miata faster?

I have a 1995 Miata that I use for autocross, track days, and time trials. I’m still finding tenths of a second here and there but for the most part I’ve plateaued a couple of seconds slower than the top Spec Miata laps. Naturally I’d like to make the car faster, because racecar.

Current Mods:

-Racing Beat Intake, Headlight NACA Duct, Racing Beat Header, Flyin Miata Exhaust

-15x8 Kosie K4R wheels with 205/50/15 RE71R tires

-Xida shocks and springs (800/500) at a very streetable ride height (4.75”)

-Flyin Miata sway bars and Racing Beat brace blocks

-Extended lower control arm ball joints

-R package end links

-R package front lip

-Hawk HP+ Brake Pads

-Custom alignment (0 toe, -3.5 degrees camber front, -3.0 degrees camber rear)

-Mazdacomp Motor Mounts

-Hardtop

-Harddog Rollbar, Sparco Sprint Seat, 6pt Harness

-Everything else is stock. The car has almost 100K miles now (purchased with 66K about 8 years ago)

The car weighs 2475 with fluids and large driver. Ultimately classing considerations may come into play but I don’t want to get bogged down with those now; I want to understand all of my options. Lets stick with a budget cap of $6K just for the sake of removing uber-expensive options from the discussion. What can I do to go faster without ruining the car's reliability (it has been pretty much bullet proof) or street-ability (I drive it to and from the track so I like my full interior, AC, power steering, cruise control, and street tires)? Forced induction might be the right answer, but let's exclude that for now as well. Right now the car starts and runs well every time under all conditions, so I don’t want to do anything that means it will run poorly at idle, or with the AC on, or struggle to start when cold or whatever.

I think the Mazda Comp bushing kit might be a good idea. I’ve read a little bit about intake manifolds (Skunk 2 and/or “Square Top”) but I’m unclear on the fitment for my 95 and the benefits that they offer. I’ve also heard about “Pro Heads” for Spec Miata but I’m unsure on the fitment, potential gains, and street ability. I’m intrigued by the idea of telling a good builder “make me a good head and it doesn’t have to be Spec Miata legal” but I’m not sure if this is a realistic option, who to turn to, or how big the gains would be. I’ve also seen a lot of people reporting solid power gains with a standalone ECU (like MS) but I don’t know anything about tuning a car; can this be done without ruining street ability or paying for hours and hours of professional tuning? I’m surprised that I don’t see any “off the shelf” tuning maps advertised for Miatas. Are there other handling mods that I haven’t done yet that fit my use case?

Supercharger or turbo are the cheapest/easiest way to make meaningful power gains, and if done well won't have much negative impact on driveability or reliability - but there's always a bit of compromise. 

In reply to Pete Gossett (Forum Supporter) :

+1 on this

Purple crack is good for a few seconds over Re-71rs.  So if you're actually within striking distance of SM, then try their rubber.

Otherwise, I'd give a call over to Flyin Miata and see how much turbo kit you can get for $6k.   I've seen people chasing  5 or 10 HP for hundreds/thousands of dollars for years by swapping parts.  I've also seen people "save" money by piecing together their own turbo kit, only to slowly and expensively replace it piece by piece into a FM kit.

A FM turbo kit will be just as reliable as a stock engined car for tens of thousands of miles, and just as drivable.

Since my car is really only a track car that I drive to and from the track (not around town), I went with the Aero route. You can follow along here, but the net result for me was 2-3 seconds faster per lap at all of my local tracks, and I'm adding more as I learn to trust the aero.

Medium downforce kit install on a Miata.

Forced induction or LS swap. 

You don't see "off the shelf" tuning maps for 25 year old Miatas because the stock ECU cannot be reflashed.

Do you have to baby those brakes at all? The HP+ is not a track pad, and if you're not having trouble with heat it may be as simple as working the brakes harder.

You're leaving some time on the table relative to a SM with those tires, but you want real street tires so maybe we leave those along. Still, perhaps a tire trailer and a set of dedicated rubber might get you the time you need. It will cost you, though, and if you're not actually racing this thing it's just a way of spending money.

Adding a good ECU will give you roughly 10 wheel hp, but you will be responsible for every part of the car's behavior including cold start. This is often glossed over. But if you combine it with some headwork and interesting cams and some valve springs, you could get yourself a higher rev range. Get the head shaved at the same time and you will end up with an interesting engine. My original 1.6 Miata got a shaved head and an ECU and it pulled 118 at the wheels with a stock cam, compared to 93 stock. But again, you'll get an okay map to start with and you'll discover that nobody wants to pay the money for OE tuning quality.

A better option, though, would be to drop in an NB engine. Preferably a VVT unit. It'll get you higher compression, a better head and the ability to tweak that VVT a little bit and get more area under the curve.

I'm not mentioning turbo here because we were told not to, but power is cheapest if you buy it in bulk :)

Keith Tanner said:

I'm not mentioning turbo here because we were told not to, but power is cheapest if you buy it in bulk :)

I did..

I am sorry I stopped reading at 2400lbs. You can cut 300-400 of that out for basically nothing. 
 

also the seam welding of my 93 along with door bars made a huge difference in driving consistency. 
 

though I would pick a class and build towards it. If this is just a fun car you want to use all over the place call fm and turbo the thing. 

You noted that was with a driver, right? And that it's a street car? I'd like to see the recipe for cutting 300-400 lbs without compromises. That means a car that is about 1800-1900 lbs wet. 

If you're using SM as a guide, 2400 is roughly what they weigh.

Keith Tanner said:

A better option, though, would be to drop in an NB engine. Preferably a VVT unit. It'll get you higher compression, a better head and the ability to tweak that VVT a little bit and get more area under the curve.

This is the route I would take. And a throw the 6-spd behind it as well. 

The easiest way to get faster lap times is to work on the driver. Sorry, but it's the advise I used to give to all of my students. Technique is worth seconds per lap. A good drivers school with an instructor who drives the same model vehicle is incredibly valueable. It's cheaper to  do a few schools, lapping days or trackdays than it is writing checks for fancy parts.

The bottom line is that none of us are able to extract 100% of the potential out of our vehicles. Those who can are the ones we watch on TV. Getting closer to that 100% mark is what you're always trying to do. I've met too many people who think that their car or motorcycle isn't fast enough. You only realize that when you put a better driver in the car and turn laps back-to-back. Data also is a huge help in that situation. It can be a humbling experience, but it's a great reality check for someone who really wants to get better behind the wheel. It give you real world data and something to shoot for.

Also, Spec Miata guys have thousands of laps in their cars, thousands! Those guys are able to wring more out of those cars than you would think possible. Oh, and race lap times include lots of time in a multi-car draft situation. That's something worth more time per lap than you would think and something you can't replicate running alone at a trackday.

Just my take on it......

I'm curious as to what a professionally ported head and 3 angle valve job would get you. I know it would be modest gains and not much bang for the buck. There is a guy on this board who I believe does this stuff for a living. 

linkery dinkery doo

Ahem.

It made 245whp on stock internals, hauls buns, and I commute to work in it and drive it 1-2 hours away for events and thrash on it regularly and have not had any driveline issues related to the supercharger. It never overheats or heat-soaks and loses power and it thrills/terrifies every passenger and co-driver I've ever put in the thing. Call Track Dog Racing up, tell 'em what you got and what you want and they send you a huge kit with every nut, bolt, rivet, hose and belt with a huge book with color pictures. I did it at home, without a lift or any power tools to really speak of.

Does classing matter? What's your endgame? Saying "I want to go faster" is a never ending treadmill. 

Keith Tanner said:

You noted that was with a driver, right? And that it's a street car? I'd like to see the recipe for cutting 300-400 lbs without compromises. That means a car that is about 1800-1900 lbs wet. 

If you're using SM as a guide, 2400 is roughly what they weigh.

Did not see driver sorry. 

Aero eg. air dam. Maybe splitter, wing, although the splitter might not be viable for your street use.

Eluding to the implications of the weight loss discussion above - It's definitely tougher if you want it to be a streetable car. Since you run a hard top, is the soft top still installed in the car? Passenger seat?

Nick - that Rotrex set up looks great. I wonder if it would fit into the MGBs that have been engine swapped to the Miata engine - looks like a fair bit of gear to pack in.

Keith hit upon what I was thinking, brakes, those may be hawk pads, but they're far from a track pad and rubber. Both in terms of tire and size on the rubber, 225 width purple crack will definitely find you time. 

With regards to your alignment setting, have you taken out a pyrometer when you come off track and seeing if you're making best use of your contact patch, or if any adjustments (either to alignment or tire pressure) would be beneficial? That's an essentially free way to find time. 

I'd start with those items, unless you're up for and or looking for a winter project x if so the BP swap Keith mentioned is the easy button without chewing through the budget. I'll add that I'd get a second exhaust cam to swap into the intake side since you'll be wanting to do MS and tuning as well. 

Also what rear end do you have in it currently, and do you have a torsion? 

My first question is are you having fun, if the answer is yes than why be obsessed with a particular lap time other than what you can do in your car.

The easy button is softer compound tires, they are worth 2 seconds a lap as a general rule. If you are close to the track (within 20 miles) I'd just drive to the track with them. I did this with my Miata years ago. If it's further than that get a rack or little tire trailer and change them track side. An electric impact makes light work of tire changes.   

To echo what lotusseven7 said; is it possible there's more to be had with some work on the driver?

Being a few seconds off SMs with Re71s is probably about right.

Wanting to make the car faster is always a slippery slope. Sticky tires = SM lap times, Aerokit got me closer to some  370Zs, Turbo got me close to some Corvettes..........and on and on it goes.  Meanwhile you suddenly realize you not having any more fun than you had before. 

I did not recommend a 1999-00 engine, I suggested a 2001-05 VVT. In my experience, there's more meat in the midrange available. It's higher compression, too.

I have yet to be convinced that the exhintake swap is anything more than internet lore. Can't do it with a VVT engine anyhow.

wheelsmithy (Joe-with-an-L) (Forum Supporter) said:

I'm curious as to what a professionally ported head and 3 angle valve job would get you. I know it would be modest gains and not much bang for the buck. There is a guy on this board who I believe does this stuff for a living. 

linkery dinkery doo

From what I have heard, "not much" seems to be the agreed upon improvement. Might help a bit if you also raised the compression at the same time. Might help a bit more if you strap a hairdryer to the engine at the same time...

Given what you've posted here, in principle I think your car should be faster than a Spec Miata.  Similar weight, vastly better suspension, a minor power disadvantage, but the major delta is tires.  RE-71Rs are great dual street/track tires, but they are not Hoosiers.  That's probably 2 seconds right there, perhaps more if it's a long lap.  Hoosiers really aren't practical for a track day car though, they're just too expensive and don't last long enough to be worth it unless you're racing.

I will +1 the aero making a huge difference to the way the car performs.  Haven't run it on my Miata, but on my BMW it was night and day.

What are you using to track lap times?  If it's any of the phone-based apps then I highly recommend a dedicated data system like those offered by AIM.  The hardware is better, yes, but the real difference is in the analysis software, and AIM's software only works with their hardware.  (I'm not a fan of that business model, but people refuse to pay for software so that's what they're stuck with).  Even with just the GPS speed trace from a Solo there is a huge amount of information that can be gleaned.  One of their dashes that also logs driver inputs (TPS, brake pressure, steering angle) will add more info as well.  (Solo 2 DL can do this, but only if the ECU outputs the data in a format it can understand, which the stock Miata one does not)

I'm going to agree with lotusseven7 about advanced instruction as well, although rather than driver's school I'd suggest you probably want to look for an individual coach.  It's really informative to have a coach drive your car with your data system running, record what he does, and use that as a reference for your own laps on the same track.

It's been noted before but it has to be reiterated - top SM drivers are fast, and they're in cars that have been obsessively developed. Simply having a car that's about the same weight with less power and a decent suspension bolted on does not automatically make the car as fast as a SM with the same driver. Then, of course, you're trying to compare to the fastest of the SM drivers on their best day. I don't think this car is competitive with a SM as it sits. It's not as stiff, it's tall, and it's on worse tires. I don't know how much work has been put into corner weighting or shock tuning. Having a nice set of shocks is only the first step.

In reply to Keith Tanner :

I apologize about misspeaking on the recommendation and ninja edited my echoing it to just BP 

Shooting from the hip:  VVT Motor, tuning, 15x9/225 or 15x10/245 setup (I'm not sure if track guys are using the 245s??).  Or R comps if you are willing to make that jump.  Track pads.

Bushings may be a good idea.  Not because they provide a big performance increase, but because your car is 25 years old and the stock rubber is likely pretty worn out.

Then obviously optimizing everything is a good idea as well.  Alignment, corner weight, brake cooling (if needed), shock settings, etc.