Long-term power options for Miata

[roninsoldier83]

One other thing that came to mind. The Torsen is the "diff" to have and you have one. What about looking for an open diff to go along - should be cheap and easy to find one. Looking at the STS rules, and what I know of you car, that is the only thing keeping you out of a class you can be competitive in. A diff swap should only take a couple hours in the garage, and it can be reversed in the future. I see Torsens selling for $400 up, I bet the open diff assemblies are cheap in comparison. Just make sure you know what diff you have first. I think that ad read 94+ torsen swap.

Just a thought, but that gives me reason to look for a STS car myself and open the options for the 99.

Good point. I'll look into it. If I decide that's the route I want to take, I would hold onto the torsen diff I'm running and swap it back in later if I boosted the car. I'm sure you're right though, I have a feeling I can find an open diff for dirt cheap and the swap shouldn't be that bad....

[ecam8000]

I'll even offer up my garage to spill the gear oil. When you get it road worthy, pull off to the side of the road with one tire on the dirt and the other on the blacktop. Drop the clutch, if the asphalt side doesn't spin, you may have a STS legal diff in there now. My torsen acts like and open diff in the air, but will spin both tires on the above test!

[roninsoldier83]

I'll even offer up my garage to spill the gear oil. When you get it road worthy, pull off to the side of the road with one tire on the dirt and the other on the blacktop. Drop the clutch, if the asphalt side doesn't spin, you may have a STS legal diff in there now. My torsen acts like and open diff in the air, but will spin both tires on the above test!

Once she gets ready to run, I'll be sure to test out the rear end, and will most definitely take you up on your offer to swap out rear pumpkins if needed!

[roninsoldier83]

I'll even offer up my garage to spill the gear oil. When you get it road worthy, pull off to the side of the road with one tire on the dirt and the other on the blacktop. Drop the clutch, if the asphalt side doesn't spin, you may have a STS legal diff in there now. My torsen acts like and open diff in the air, but will spin both tires on the above test!

Hey Eric,

I'm just looking at VLSD's right now (stock in 90-93's, legal for STS), and seriously making this a consideration, but I'm curious about the legality of the A/C being removed and the power steering de-powered. Since you were able to get a car without A/C or power steering from the factory, is the lack of those two features legal in STS? I'm reading the SCCA solo rules for Street Touring, and it doesn't specifically mention it. Any ideas?

[roninsoldier83]

Well, got my answer.... de-powering a steering rack is illegal in ST and SP classes.... FML. It wouldn't be such a big deal, except I know the previous owner cut wiring that went to the P/S pump, so that's just another headache waiting to happen, and more money down the drain.

At this point, the guy who did all of these mods, if he raced this car, I would seriously like to know what class he competed in, as it's not fit for Spec Miata, stock, ST or SP, and it's damn sure not even close to being competitive in anything higher. WTF?!?

[94mx5]

Honestly, unsure what the PS wiring does. I have never bothered to figure it out. First car I have ever seen with a wire to PS. Maybe temp sensor? Anyways, slap it all together and run it as-is. You might be surprised.

IF I were to do a swap on the cheap, I would run a 1.8 engine with some minor intake/exhaust mods. That is even cheaper and maybe easier than a 1.6 turbo. If you want the ultimate, go built 2.0 stroker with turbo, or LS1. Either way, it won't be cheap and difficult to ever get your investment back.

[roninsoldier83]

Honestly, unsure what the PS wiring does. I have never bothered to figure it out. First car I have ever seen with a wire to PS. Maybe temp sensor? Anyways, slap it all together and run it as-is. You might be surprised.

IF I were to do a swap on the cheap, I would run a 1.8 engine with some minor intake/exhaust mods. That is even cheaper and maybe easier than a 1.6 turbo. If you want the ultimate, go built 2.0 stroker with turbo, or LS1. Either way, it won't be cheap and difficult to ever get your investment back.

Maybe you're right.... I don't suppose you happen to have an extra P/S pump just laying around?

[Dange]

if depowering the rack is illegal. what about swapping in a manual rack? more turns from lock to lock so its not as ideal as a depowered power rack. but on an na build thats quite a bit of hp and the weight savings from not having a ps pump or ac pump. that i would suggest you put back on with a hdhc rollbar. it helps your handling ALOT


as far as power my last miata was a 1.6l na build. it was a blast and a half and you can make it into the gocart i think you want. and id be happy to help you out.
this is one of the highest hp naturally aspirated miatas i know of.
[ame="http://www.youtube.com/watch?v=c2MTdigVyt4"]YouTube - FujiRacing Miata 4 3 sec. 0-60 MPH 184 WHP[/ame]

its damn quick for what it is i have no doubt even with less hp, he would rape my turbo miata.
if you get the 99 head its a better flowing head, and go with a cheap ebay header, and an intake, do a fidanza 8lb flywheel, and stage 1 clutch. you already have a good suspension, although i would add a RSB on a looser setting because just running the front is going to add a bit of understeering characteristics

if going all out. my buddy had a built low compression 1.8 turbo that was putting out almost as much hp as his current ls2 swap. the engine can handle it. as he actually blew up a whipple ubercharger by trying to get more boost and the engine wasn't even phased. so he swapped in a turbo.
so i'd go with low comp. pistons, H beam rods, 99 head, good rings and a 28 series turbo you should be fine. and it saves you alot of money
the ultimate is the 2.0 stroker, and the current record is 816 rwhp in a 2.0 stroked miata. but at that point the car is pretty much unsuable in anything other than dragracing.

[erod550]

^^ I want my 90 to sound and move like that. Mmmmmmm

[roninsoldier83]

if depowering the rack is illegal. what about swapping in a manual rack? more turns from lock to lock so its not as ideal as a depowered power rack. but on an na build thats quite a bit of hp and the weight savings from not having a ps pump or ac pump. that i would suggest you put back on with a hdhc rollbar. it helps your handling ALOT


as far as power my last miata was a 1.6l na build. it was a blast and a half and you can make it into the gocart i think you want. and id be happy to help you out.
this is one of the highest hp naturally aspirated miatas i know of.
YouTube - FujiRacing Miata 4 3 sec. 0-60 MPH 184 WHP

its damn quick for what it is i have no doubt even with less hp, he would rape my turbo miata.
if you get the 99 head its a better flowing head, and go with a cheap ebay header, and an intake, do a fidanza 8lb flywheel, and stage 1 clutch. you already have a good suspension, although i would add a RSB on a looser setting because just running the front is going to add a bit of understeering characteristics

if going all out. my buddy had a built low compression 1.8 turbo that was putting out almost as much hp as his current ls2 swap. the engine can handle it. as he actually blew up a whipple ubercharger by trying to get more boost and the engine wasn't even phased. so he swapped in a turbo.
so i'd go with low comp. pistons, H beam rods, 99 head, good rings and a 28 series turbo you should be fine. and it saves you alot of money
the ultimate is the 2.0 stroker, and the current record is 816 rwhp in a 2.0 stroked miata. but at that point the car is pretty much unsuable in anything other than dragracing.

The car is getting painted right now, so I can't verify it, but according to the previous owner, the P/S lines are looped, so I should be able to put a P/S pump back in the car (can find them used from $50-$90 on Ebay), pick up a belt for it, and just run P/S to avoid additional hassle. Which, I'll take a look at the lines when I get the car back, and decide what I want to do from there. At this point though, I'd just like to be able to play with the car in a reasonable autoX class haha!

As it turns out, the rules state you can remove things as long as there was a factory option for it and you have to match the factory option specs. My car apparently had both the A package (power steering, leather wrapped steering wheel, allow wheels & AM/FM cassette) and B package (power windows, power antenna & cruise control), but fortunately, A/C was a standalone option, it wasn't standard on any package, so it appears to be ok to remove it. As such, if I put a power steering pump back in (easier than converting to a manual rack), I'm not going to touch the A/C.

That NA (no pun intended) Miata is SICK!! I bet that thing is a blast to drive!

I might just take you up on your offer to make this a fast NA car in the interim between boosting it.

[94mx5]

I might have a PS pump. Will have to take a look. Personally, the PS isn't going to suck as much hp as you would think. There are mods that can be made to help gain that back easily.

[roninsoldier83]

I might have a PS pump. Will have to take a look. Personally, the PS isn't going to suck as much hp as you would think. There are mods that can be made to help gain that back easily.

If you have an extra one, I would likely be willing to take if off your hands I'm not too concerned with how much extra power it would suck up (I'm thinking maybe 1-2hp), and honestly, if I ran in STS for a while, I would likely pick up a header/high flow cat & MS standalone ECU and tune the car to gain the power right back (plus some).

Define irony: in STS you're allowed to run a full standalone ECU, but you can't de-power a P/S rack

[ecam8000]

I think I agree (I'll have to ask the wife) with all the Rule stuff above. If the car was offered with a "package" you can update/backdate or adjust to that package. That does not mean you can put the 2.0 from a 2006 into the NA, but if a sport package was offered, you can convert your non sport into one. If an A/C delete was offered - you can yank the A/C. Convert to manual, radio delete, crank windows, etc. I doubt the depowered P/S is allowed.

If you are looking for a stock LSD for your car, remember we think the rear has been upgraded to the 94+ diff, axles and who knows what else. 94+ I think the options are open and the Torsen.

[roninsoldier83]

Honestly, at this point, I'm tossing around with the idea of just selling the car. I've already purchased/have to replace the following:

-Hood/lids
-Rear window
-Shifter/bushings
-Cooling fans/temp sending unit/relay
-Brake pads
-Tires
-Paint
-Tein suspension adjustment tool (previous owner lost the old one...)
-Parking light

And now, just to get the damn thing legal to run in either STS, STR or CSP, I would have to either swap out to a manual rack, or re-power the power steering, and if I want to run in STS, find a new stock rear diff/axles.... at this point, I haven't even had the car 2 weeks, and it's starting to make more sense financially to just sell this thing, recoup (some of) my cash, and buy something stock, as the money I've having to sink into it is starting to outweigh the price I saved on the car/mods that were on the car.

I'm really starting to regret not just buying another SW20 MR2 turbo....

After looking into what "looping the P/S lines" involves, the majority of people who do it cut the hard lines coming from the rack.... meaning, going back to P/S involves picking up a new rack, pump and all the hard lines between the two. I'm starting to remember why I used to have a personal rule against buying cars that were modded: I got tired of fixing mistakes other idiots made.

Forgive my negativity, but I'm starting to think sinking $3k-$4k into a car that's maybe worth $3k, just to get it back to stock form might be a bad idea. [/rant]

[erod550]

Were you really buying the car to win at autocross though? Why not just run it as is and while you won't be competitive with the top guys, you will still have fun, and the car will still be a blast to drive.