Plan for Project '04 Mazdaspeed Miata (err, MX-5?)

[roninsoldier83]

So, I've owned my new-to-me '04 Mazdaspeed MX-5 (there's actually no "Miata" badge on the MSM....) for a few weeks now. During that time I've been researching a potential upgrade path for the car. I've decided that the car will remain primarily a street car that will see the occasional open lap track day and autoX event. As such, it won't be a "hardcore track rat". Nor will it be built to the specific limits of any particular autoX class- although I'm not too happy about the fact that the MSM isn't even eligible for the SCCA's ST(R) class! While stock (or close to), there's a good chance I might show up to local SCCA meets & run in the new E Street class, but I don't plan on basing my mod path around it- I would really just be going for seat time & to have fun!

I'm a lowly civil servant; so, funding my project is going to take quite a bit of time. I went way over my intended budget when I bought the car, so it's going to be a while for me to even begin to put any money towards it. No biggie, I'm enjoying the heck out of it in stock form for the time being and I'm sure I will appreciate the difference mods will make a bit more if I can really feel the improvements over stock after driving it like this for a while.

With that all said, here's a basic outline of what I plan on doing to the car:

First and foremost- Safety:

-I can't get on a track without having a roll bar. After a good amount of research, I think I'm going to get the Boss Frog Clearview Maxx (w/padding & harness bar), based on rationale from previous thread:
http://www.coloradomazdaclub.com/forums/showthread.php?t=9058
-Harnesses.

Drivetrain:

-TWM Phantom hybrid shift knob.
-Beefier motor mounts & diff mount.
-Possible eventual switch to taller 3.63 gears. WAY down the road. We'll see. <---- This will be completely based on perceived needs after all power mods are added.


Suspension/Chassis:

-FM frame rails.
-Re-valve OEM Bilstein shocks.
-Racing Beat 1.125" FSB (w/stock MSM 14mm RSB )
-Custom alignment.
-Possible other chassis braces- frog arms, rear subframe brace, ect.

^^Honestly, the OEM MSM suspension is pretty good for a street car IMO. At this point I feel as though the car is better than I am; so before I go throwing lots of cash at the suspension I feel I need to get some serious seat time and figure out what I think is actually lacking- besides my own skill level!

Interior:

-Mod stock seat to include foamectomy and mounting to the floor.
-Eventual aftermarket seats of some sort. -Don't get me wrong, I actually like the stock seats, or at least the bolstering and overall comfort. I would just like them to be a couple inches lower and still maintain a high seat-back/head-rest. At this point my knees end up touching the wheel a lot (6'2" 210 lbs, 34" inseam).. As such, aftermarket seats appear be the ticket. Recommendations?
-Gauges: Since the Miata is limited on space, I'll likely go with boost and oil temp.

Wheels & Tires:

-Will likely run the factory Racing Hart 17x7 wheels on the street, but will pickup a set of decent summer tires. I'm leaning towards Michelin Pilot Cup Sports since the car will primarily be a street car. Although if I step it up from stock size tires (205/40/17) to 215/40/17 tires, there are actually better tires available (Extreme summer performance), so I might just go that route.
-I'm thinking about smaller wheels & tires for track use. 15x8 wheels seem to be popular. I don't plan on getting competitive enough to need R comps. I like the look of the Enkei PF01's... This would be WAY down the line...
-When I eventually get a set of 15x8 wheels, I think I'll invest in a set of 225/45/15 performance tires. I've considered mounting 205/50/15's, but with the power the car will be making, the 225's will likely be the better choice for putting it down.

Brakes:

-The traditional trio of stainless steel lines, better pads & higher temp fluid.

^^^With that trio, I would just see how they did on a track before spending anymore cash on bigger calipers. I've heard the later "sport" brakes this car comes with are actually pretty fade resistant.

Engine:


-FM intake kit, which includes intake, TB piping and new BPV. I want to stick with FM in case I ever decide to swap over to their larger turbo setup.
-Larger intercooler; likely of the cheap, yet effective eBay variety that costs significantly less than the name brand versions. Fab9 tuning perhaps?
-FM Downpipe- allegedly FM claims it still passes emissions. The stock cat-back will eventually go away as well in the name of lower exhaust temps.
-Engine management of some sort; likely some flavor of Megasquirt due to price along with sensors to run it (GM IAT, LC1 wideband, ect).
-Bigger injectors. At this point, I think that 450's would be MORE than enough, but then again, if I ever felt like running E85 on another car...
-Larger radiator (likely FM's cross-flow radiator) & FM's stage 2 fans.
-Oil cooler. Also likely of the FM flavor.

^^^I think ~225whp in this car would be more than enough. The guys at sea level seem to run low 13's around 103-105+mph with that setup, which is plenty fast for a car that's not made to drag race.

Of course the car will also be getting premium fluids and I'll be doing my best to stay on top of preventative maintenance.

From everything I've read, the OEM motor, clutch, transmission and differential should take the extra power and stress without much of a complaint (assuming I keep the motor cool enough). It's not much of a "monster build" per se, but I think it would still keep the car fairly balanced and make for a fun little machine! Heck, the car is already ridiculously fun to drive! I think with my intended mod path, it'll only get better. As my skills improve, I'm sure suspension will eventually be on the list....

Thoughts? Recommendations?

Cheers!

-Brandon

[erod550]

I would keep your stock diff gears. If you get some good rubber, I don't think you'll have traction issues with 225whp and that would be the only reason to go taller unless you just really hate shifting, but 3.63 isn't that much taller than the 3.91 you have now. And unless you're having traction issues in 1st, you're going to lose acceleration in every gear, so that wouldn't be worth it to me.

I love the 4.10s in my Mustang. One of the best things I did to the car. Yea I shift more (really I end up skipping gears a lot during regular driving), but the acceleration gain 2nd-4th was extremely noticeable coming from 3.55s. Also, still being NA and only ~330-340whp (uncorrected up here), I don't really have traction issues with the 275s that are on there right now. If/when I ever supercharge, I might go back to a taller gear because with 550whp+ 1st and 2nd will probably be useless on the street, but until then I will keep them short.

[roninsoldier83]

I hear what you're saying, although the MSM doesn't come with the 3.91's that other 6-speed Miata's come with. It has 4.10's from the factory combined with a lower redline than other NB Miata's (6500rpm vs 7000rpm). The result? Redline in 2nd gear occurs at about ~49mph. Which is why they're not very popular in autoX- they require a lot of 2-3 & 3-2 shifts while dodging cones on most courses.

And unfortunately the NB's wheel wells aren't going to accept the 275+ wide tires your Stang will without some serious work haha. On a wider 8" wheel, I'm thinking 225 sounds about right as most of the Miata guys say that you're going to run into issues trying to run anything much wider than that. So, the super low gearing & relatively thin tires might not play so nice with the kind of power I plan on getting out of it . Like I said though, I'll see how the car handles it & go from there.

[Saul_Good]

NB body, imma call it a Miata :P

The ONE biggest most noticeable mod you can make is a good set of wheels/tires properly matched. Depending on the offset you choose for 15x8, 225s may/may not fit w/o rolling fenders.

Goodwin racing sells some decently priced 15x8 +25 that are 12-13lbs. Most miata forums will say to use 205s with 8in wheels (i am ) and the topic has been beaten to death but basically wheel slightly wider than the width of the tire gives more contact patch and response at a lower psi. 225 on an 8in wheel is still not bad but it has been proven to not be any faster than a 205 on 8in wheel (assuming same brand tires). 225 on 9in is really fast but again you'll need a good offset to avoid rubbing. This info is regarding street tires with the extreme performance summer tire category in particular. Slicks is a whole different game.

TL;DR -- Make wheel/tire combo top priority after safety.

Have fun!

[erod550]

4.10s are even better. But yea if you're doing it for a better powerband for autocross and you don't mind losing a bit of acceleration, you should mod the car to suit the purpose you want to use it for. I just wouldn't do it for traction issues because even with 205s or 225s I think you can easily put down 225whp.

[roninsoldier83]

NB body, imma call it a Miata :P

The ONE biggest most noticeable mod you can make is a good set of wheels/tires properly matched. Depending on the offset you choose for 15x8, 225s may/may not fit w/o rolling fenders.

Goodwin racing sells some decently priced 15x8 +25 that are 12-13lbs. Most miata forums will say to use 205s with 8in wheels (i am ) and the topic has been beaten to death but basically wheel slightly wider than the width of the tire gives more contact patch and response at a lower psi. 225 on an 8in wheel is still not bad but it has been proven to not be any faster than a 205 on 8in wheel (assuming same brand tires). 225 on 9in is really fast but again you'll need a good offset to avoid rubbing. This info is regarding street tires with the extreme performance summer tire category in particular. Slicks is a whole different game.

TL;DR -- Make wheel/tire combo top priority after safety.

Have fun!

I would agree with that statement. It's been a while since I've had a project car (due to life changes a couple years back), but this is my 15th vehicle, several of which have been highly modified in the past and that one statement has always been true: the largest measurable increases in handling/grip have always been a result of wider, stickier tires.

Although I'm really not trying to build the "fastest" setup on the block, as I'm more concerned with the car remaining fun and streetable. I remember my old Subaru STI; I had that car riding on KW coil-overs, larger sway bars, stiffer top hats (in the rear / camber plates in the front), with an aggressive alignment and running wider, stickier rubber than it came with from the factory.. the car was seriously fast. Although the suspension mods didn't really make the car much more fun to drive; mostly due to the level of grip being so high that it was almost unreachable on the street. I don't want to do the same thing with the MSM.

Like I mentioned, if I got an extra set of wheels/tires, it would really only be for the track. No use destroying tires that I will also be using to commute to work The 15x8's seem like the smallest wheels that fit over the factory calipers and still offer a decent selection of sporty tire options. In my mind, smaller diameter wheels= cheaper [more disposable] tires (and wheels for that matter).

Thanks for the info on the 205's vs 225's! I guess I have a bit more homework to do!

[roninsoldier83]

4.10s are even better. But yea if you're doing it for a better powerband for autocross and you don't mind losing a bit of acceleration, you should mod the car to suit the purpose you want to use it for. I just wouldn't do it for traction issues because even with 205s or 225s I think you can easily put down 225whp.

Well, I think it depends. Obviously the 4.10's are going to offer greater torque multiplication, which in theory should increase the rate of acceleration. However, if you're spending more time shifting as a result of the lower gear ratio, there's a good chance you might end up negating the acceleration benefits that the lower (numerically higher) gears offer. If that is coupled with a possible loss of traction, well, we have ourselves a legitimate debate.

Taller gears could not only help with autoX times on most courses, but also possibly with 1/4 mile drags (if they can cut a shift out of your time), some road courses (that taller gearing might be more suitable in taking down your shifts), theoretical top speed (lol) and lower RPM freeway cruising (which could potentially translate into better fuel economy), just to name a few things. I'm just sayin' buddy.

Although if we look at the powerband of the stock MSM, it's pretty easy to see why Mazda gave this car short gear ratios: in factory trim, it has a very narrow powerband. Really, in order for the car to pull, it needs to be between 4500-6500rpm, whereas a naturally aspirated NB has a relatively flat torque curve as well as a higher redline and can better utilize taller gearing- hence the taller gearing in the 6MT NB cars, to include the specialty [sportier] models like the 10AE. Once you start modding the MSM, turbo lag is mitigated considerably, allowing you to access higher torque figures at a much lower RPM. Aftermarket ECU's also allow you to set your own redline, which helps further as the stock IHI turbo appears to still pull hard past 7000+rpms. Overall, the MSM's powerband becomes much more broad and usable and could likely benefit from slightly taller gearing... hence why quite a few of the MSM and other turbo Miata guys advocate taller rear end gears.

It really is too bad they don't let lightly modded MSM's (with bolt-ons & taller gears) play in STR... and it also makes me wonder why they don't let them run in STR? I would wager that it would give the S2000's & NC Miata's a pretty good run for their money!

But again, like I said, I'm not going to base my decisions on theories and conjecture. I'll mod the car accordingly, and if I feel that the uber-short gearing is hindering the car due to excessive shifting or traction issues, well, I'll address it as needed. In the meantime I'll just enjoy it as is.

[/end_devil's_advocate]

[erod550]

Obviously it's not an easy thing to compare side by side since it's a complicated and expensive thing to swap out rear gears, so I can't say I've compared them directly, but I'm pretty sure that even adding an extra shift in the 1/4 that going to 4.10s from 3.55s gained me time. It also made a big difference in roll races where you're pretty much just going to shift twice anyway unless you're trying to do 120+ on the street.

But I can definitely see where it's something that can cause inconveniences depending on what you're doing with the car, and I did lose 2-3mpg on the highway from doing it, as I'm about 500rpm higher in 6th now at 80mph. But if you're waiting until the car is modded how you want it before messing with the gearing, then you'll have a good idea of whether it will be a good mod for you or not.

Side note: My NA has 4.30s lol. It helps with the illusion that the car is quick even though it is painfully slow.

[Saul_Good]

U can play in STR. Id be okay. Just go on RMsolo and ask.

[roninsoldier83]

Obviously it's not an easy thing to compare side by side since it's a complicated and expensive thing to swap out rear gears, so I can't say I've compared them directly, but I'm pretty sure that even adding an extra shift in the 1/4 that going to 4.10s from 3.55s gained me time. It also made a big difference in roll races where you're pretty much just going to shift twice anyway unless you're trying to do 120+ on the street.

But I can definitely see where it's something that can cause inconveniences depending on what you're doing with the car, and I did lose 2-3mpg on the highway from doing it, as I'm about 500rpm higher in 6th now at 80mph. But if you're waiting until the car is modded how you want it before messing with the gearing, then you'll have a good idea of whether it will be a good mod for you or not.

Side note: My NA has 4.30s lol. It helps with the illusion that the car is quick even though it is painfully slow.

Did you ever take it to the strip prior to swapping out to the 4.10's? I would be pretty curious... what gear do the 5.0 Stangs end the 1/4 in with 3.55's vs 4.10's?

It's been a few years, but I remember the gearing in my old NA6 lol... and you're right, it made the car seem much peppier than it actually was!

U can play in STR. Id be okay. Just go on RMsolo and ask.

I suppose when the time comes, I might just do that. Maybe you're right and they wouldn't really care locally. It's just SCCA Solo II rules state that the Miata turbo (MSM) is not eligible for any of the ST* classes.

[erod550]

I didn't take it to the strip before the swap. 3.55s you're ending in 4th, 3.73s (the shortest factory option) you're right on the edge, shifting pretty much just as you cross the line. The 4.10s you shift into 5th just before the finish. This is all stock/relatively close to stock. Once you boost you'll be going into 5th regardless, heh.

[Huzer]

I was just thumbing through a somewhat recent issue of Grassroots and they have a "buyer's guide" spread on the MSM. Pretty good read.

[roninsoldier83]

I was just thumbing through a somewhat recent issue of Grassroots and they have a "buyer's guide" spread on the MSM. Pretty good read.

Do you have a link by chance? I'd love to take a peek at it.


I've been doing a bit more research in recent weeks and have changed my mind a bit about some of the mods I eventually plan on doing to the MSM:

-I think I'm going to skip the short shift kit. As I've gotten used to the factory shifter, it's really not bad.. not 5-speed smooth, but not bad at all. I think some good tranny fluid, new bushings and maybe some stiffer motor & diff mounts should clear up any complaints I have. Although I'll likely still do a heavier shift knob. Recommendations?

-After all we've talked about, I think I'm also going to join the Boss Frog Clearview Maxx club for reasons you guys pointed out to me. It just seems like that bar that makes the most sense to someone like myself.

-Other than maybe revalving the stock Bilstein's & getting a good alignment, I really think I'm going to leave the suspension alone. It's pretty damn good for a street car. Again, I might get a bigger bar to put at one end or the other, but even then, at this point I think I'm going to need to become a better driver before I start swapping out parts.

-I think I've realized one of the car's weakest links- the chassis. Even with the extra Mazdaspeed braces it comes with from the factory, the chassis still quivers over bumps & such. Since it's still going to be a street car (i.e. no full cage, ect), I think I'll likely eventually add extra bracing to key points of the car. I've heard that a good roll bar tightens up the rear significantly, so hopefully the Boss Frog bar will help (comments from people running a roll bar?). I think I'm also going to look into the fender bracing (i.e. Boss Frog Arms, ect) and heavier frame rail bracing, ect.

[coloskydiver]

It is hard for me to give a before and after comparison but during my build I went with the Frog Arms and a Boss Frog Roll bar. The car was very composed on both the street and track. The other thing that I felt made a difference was the harness bar that braced the car laterally. The V8 Miata guys felt that the new transmission mount help brace the car as well. I do know that the Frog Arm were more of a must for the NA guys than the NB cars but still believe in the product. Fairly cheep and easy to install. My 2 cents.

[Saul_Good]

I bought my car with the rollbar so i have no before/after comments, but i hear it doesnt do much in way of chassis stiffening. Im hoping the harness bar i out in helped. Before you do anything to the car, go to the track and establish a baseline time. My 2 pennies.

Edit: nevermind u at least need that rollbar first and/or hardtop.