XS Hack

So I bought a Miata in april after selling my EP autocross VW Rabbit. I took the old FWD car pretty far and had tons of fun, but I thought the next step in my driving skills (and lowering my run times) was some RWD action.

I had a few false starts. I looked seriously at building a lotus 7 replica, then bought a couple of datsun roadsters from a friend. Originally I planned to put in a Toyota 2rz and 5 speed trans with a HX35 turbo and modify the sheet metal to fit some real tire under it. To make one good Datsun I was going to need to reinvent pretty much every part: motor/trans, rear axle and suspension, brakes, cooling, steering system etc... In the end I figured it would take me a couple years. After staring at the rusty pieces of junk for a few months I decided what I really needed was a car to drive, not a long term project. I got rid of the Datsuns and convinced my friends that buying a Miata didn't automatically mean I liked dudes.

I found a good looking '99 near me that was nice and cheap. The Craigslist pictures looked good, but it had it's problems. Someone had the hood repainted without fixing any of the existing rock chips, of which there are many. The top is ripped in several places, the worst of which is right above the drivers head. Did I mention it was pretty cheap? I brought it home, cleaned it up and started driving it every day. Before autocross season started I ordered some coil overs, autokonnexion fender flares, 15x10 6ULs, and some 10 inch wide Avon slicks. The car is a lot of fun on course but lacking in the horsepower and rear traction.

So I started reading threads and tech bits on this forum, which seems very helpful and comical. Now I am planning some winter and spring modifications to the car. In the last few weeks I have purchased:

A rolled KIA Sportage
RX7 FD transmission
engine stand
Holset HX35
Megasquirt ms3x and wideband Ox sensor

I am on a pretty tight budget, and would like to have this thing turbofied and back on the road before next summer. Every week I seem to add more things to the "need" list. I'll start a build thread soon to keep track of what the hell I'm doing and push me forward.

triple88a

iTrader: (2)

Interesting start, post some pics man. Planning on building the motor for that turbo?

XS Hack

not building the motor necessarily, some rebuild action for piece of mind. Though I did disassemble it today, Everything looked really good in the FE3. I will put in a fresh head gasket, rings, head studs (maybe), and main bearings. it doesn't need any boring. I am going to get all the parts washed and start with cleaning up the cylinder head ports. nothing crazy, just some un-shrouding and cleaning casting flash out. I will post some pics tomorrow, after I check out the "how to post pics" thread.

Stay tuned

triple88a

iTrader: (2)

Whats the power you're looking to get? From memory that was a giant turbo wasnt it?

trackslut

I think that's a decently huge one. Isn't that the stock Dodge 5.9 turbo?

thenuge26

iTrader: (2)

OP, the first rule of turbocharging is don't build a turbo kit around a turbo. Sell the HX35 and buy something useful for autox. What are your power goals? If you are not building the engine, they will be WAY under what the Holset can do. Get a T25 from an SR20 for the quick spool.

Also if you put that engine back together without putting forged rods in, we will find you and kill you. Even some cheap ebay ones are better than stock.

hobbs

iTrader: (10)

I would also suggest against the HX35, had a friend with a H1C on a SR that did not hit until 4,000-4,5000 RPM. If you're dead set on going with a holset take a look at the HX30, I believe they are pretty close to the GT2860 series turbos in terms of size and performance.

Braineack

iTrader: (62)

Welcome, XS Hack. Check out the Miata Gallery and post up some pics!

Miater

There are a lot of Supra guys runnin those HX35 turbos. If that says anything about the power band of it. That will scream with the right setup $$, on the freeway for a second or two in every gear, that you can find traction in.

XS Hack

Wow, a lot of responses. I'll try to address some questions:

HP: I am shooting for 350 whp on E85, depending on what kind of mood I'm in. Maybe less for everyday use and more if I'm feeling sprite. I think the HX35 should do these kind of numbers in the 15-18 psi range, we will see.

The Kia FE3 has HUGE connecting rods, they make volkswagen rods look small, and where I come from VW rods are good for 300 HP. The pistons also have a lot of meat above the top ringland. I will not be replacing rods or pistons. Some bearings, cleaning, and cleanup of the head casting are in order.

Turbo spool: I don't want a car that is spooling/burning out while trying to exit tight corners on the autocross circuit. If it doesn't spool until 3500 rpm that will be great.

I want this car to be a fun weekend toy as well.The HX35 seems scary because it is from a large diesel truck, but those are terrible flowing, cold exhaust having crap. My shop mate just finished his Mercedes 190e 2.3 16v turbo setup with an hx35 and it starts spooling at 3,000 rpm, and made 330 horse on a Dynojet at 13 psi. I AM NOT WORRIED ABOUT TURBO SIZE. if it proves to be too big I will get something different, things can always be changed.

My old Rabbit with ITB's, 13:1, 306 degree cam in a 1.5l engine that made peak hp to 10,000 rpm:

latena

No chance you have an XS650 with a sidecar?

XS Hack

No Sidecar, but I have hacked up a XS650 into a cafe-ish scoot. It isn't quite traditional Cafe styling, so I call it a hack. Can you see this picture?

latena

Can see that picture. Here is my 81. Pamco and PMA, nothing special other than that:

XS Hack

Nice! My bike looked very similar when I started, heritage special but mine had the spoked wheels, not the mags. I have a Pamco and whole new PMA charging system waiting to go in this bike when I get busy on it. The charging issues were the whole reason I took it off the road to begin with. Here is a more recent shot with the new 2 into 1 exhaust I made. Also the Jetta in the background is my daily driver.

latena

Yeah, I just sold an 83 Heritage Special that I pulled out of a neighbors barn. I have a whole nother engine and a set of regular spoke wheels in the garage if I ever get around to it. Bike is interesting, not too many monoshocks out there.

XS Hack

Okay, Here are some pictures of the topic at hand:

When I got it. stock 99 base model, no A/C or power windows, stock CD player still etc..



Building a rollbar was first! knowing someone with a tubing bender and notcher is awesome.





Then I had to get these Huge 23x10 Avons on 15x10 6ULs to fit. If I had been paying more attention I would have got 15x9s, but these were the only ones in stock and eventually I will need as much tire as I can get.

The grey part is the inner fender after cutting the outer fender off and making some incisions.


Once the cuts are made in the inner fender I applied deadblow until the inner and outer pieces touched. tack weld here and there and cut off the excess. All welded up, before the seam sealer went on



Done for now

triple88a

iTrader: (2)

Cheers mate, looking at this thread, you will do well here :P

e1_griego

Were you at EESCC event #8 running in xp? I came over and checked out your car -- we were trying to figure out why you were in XP and just figured you had v8

XS Hack

Yeah that was me. The only reason I'm in a prepared class is due to the slicks, and that (xp) Is the class I'm building the car for.

e1_griego

I figured once I peeked my head under the car looking for longtubes or something

I was in the black silvia-front 240sx. I run in SM.