V8 Miata, who's done one

I add more to the weight of the car by sitting in it, than I did by adding the V8! Unfortunately it would also be easier to take weight off the driver than the car.

Alan Cesar wrote: My friend and LeMons driver built himself an LS1 Miata. He overspent on a number of things, he says, but he did a complete build -- including seats, big brakes, wheels, tires, roll bar, SFI bellhousing, limited slip diff, coil-overs, new front bumper, camshaft, tuning and so on. He used the Flyin' Miata kit. All told, he said he spent close to 30 grand. Maybe slightly more than that, my memory's fuzzy. Did all the work (except the tuning) himself. Skilled guy, too. Top-notch, show-quality work; he's won a few trophies already. He said if I wanted him to build me a similar car, he'd charge a bit over 20 grand. Maybe 24k? Again, fuzzy memory. No doubt you could build one for quite a bit less if you forgo a lot of the upgrades. He's been surprised that it's not an oversteering, unwieldy drift machine; it's got plenty of traction. He has details on his blog, and he'll be at Holley LSx Fest this weekend. Dyno http://www.johnnycichowski.com/2011/03/dyno-time.html Scales http://www.johnnycichowski.com/2011/03/ls1-miatatale-of-scales.html Autocross http://www.johnnycichowski.com/2011/05/we-got-ourselves-race-car-wcmc-auto-x.html

hi Allen hows Daytona? i did the swap and i was expecting the car to be allot heavier. 2400 lbs was a big surprise when i was expecting 2700. i hit the scales at full weight full tank of gas and full of fluids. i have some areas to lose some weight. this weekend I'm going to be removing my steel scatter shield and replacing it with an aluminum one. also i was going to source an aluminum rear diff out of a cobra. this winter we will be tubing the front and rear end. hopefully next year we can brake the 2299lbs mark.

Here is a how to guide if it would help. http://www.youtube.com/watch_popup?v=8rJZg6m341w

nderwater wrote: Curb weight for *the lightest* NB is ~2350. Later and fully-optioned cars edge up toward 2500 with a full tank of fuel.

IIRC, 99 Sport Packages were 2299.

Zombie thread!

FYI, I think my Targa Miata was right around 2350 with the L33, full weather protection, skid plates and a cage.

I forgot I even started this thread. Funny, but fast forward 2 years and I'm working on an LS-powered 944. I would rather have done the miata but from what Keith and others have said, there's much more work in getting it in the miata and I came upon this stalled project for way too good a price.

Need details on the LS 944, build thread?

Guy around here started doing this back when the Miatas first came out using Ford V8s. The limitation was always rubber - unless you hack up the body you can't get enough rubber under there to take advantage of the power. The net result has always been that the V8 Miatas aren't a lot faster than the same engine hauling the heavier Mustang it came from.

I respectfully disagree. That's not been my experience, unless you're possibly talking quarter mile times.

this thread pleases me

CLynn85 wrote: Need details on the LS 944, build thread?

My progress is pretty slow, so I've kinda been holding off 'till I have some substance. Basically, the engine is in, the brakes are mostly done and I gots some fat rubber. I have to weld in the battery panel soon, and start the wiring. My headers should be here any day.

The battery panel must have been rusted (though they don't rust real bad usually) and the PO cut it out. It took MONTHS for me to find a donor panel (paid waaaay too much for it).

I think my lungs have healed up enough from my bout with pneumonia that I can get out there over Christmas break to weld the panel in.

charchri4 wrote: Here is a how to guide if it would help. http://www.youtube.com/watch_popup?v=8rJZg6m341w

welcome aboard

OK feel free to correct me but I do know that an early Ford 5.0 motor with aluminum heads weighs in at 424lbs and I seem to recall that the T-5 tranny weighs something like 78lbs. I though that event he the Chevy V8's were a good 50lbs more than that. Granted SBC parts are far more abundant.

With that said Miata motors are heavy and turbo 4 cylinder engines tend to weigh nearly as much as a V8, it's been a while but the figure of 360lbs comes to mind. I've only briefly driven V8 Miata and the balance seemed fine compared to the dozens of 4 cylinder Miatas I've driven.

 Tom

The LS engines we use are all aluminum - head and block. A bit different from the first three generations of SBC. Even with the hefty T56, the Miata gains right around 200 lbs with the conversion when compared to the original.

Miata motors aren't terribly heavy, they're pretty normal for an iron block, aluminum head DOHC four of similar size. I figured out how much an aluminum block would save once, and it wasn't a big amount. Something like 15-30 lbs.

To those who are considering this subject. I've spent some time in an ls1/t56 powered NA chassis miata and can report that putting the power down was not remotely the problem that I had expected it to be. I found it much more enjoyable than the multiple boosted (both blown and turbo'd) ones i've driven. It was deceivingly fast, I found myself feeling like the (wilwood) brakes were not sufficient at the end of straightaways, when in reality it was mostly that I had collected more speed than I realized. I don't know that it was as "fast" as thought it would be, (I had expected more brutality, and my expectations were quite high) but it was much better to drive than I would have expected. I highly recommend building one if miatas are your thing. If you do elect to, I recommend a good cam to help with the brutality part, as a cam wakes up ls motors in a big way for pretty cheap $.

Agreed, it was the amount of traction that surprised me the first time too.

Keith Tanner wrote: The LS engines we use are all aluminum - head and block. A bit different from the first three generations of SBC. Even with the hefty T56, the Miata gains right around 200 lbs with the conversion when compared to the original. Miata motors aren't terribly heavy, they're pretty normal for an iron block, aluminum head DOHC four of similar size. I figured out how much an aluminum block would save once, and it wasn't a big amount. Something like 15-30 lbs.

geez, had i won that mega millions the other day I would have come to see you to have you build me one of these cars.

I don't know that it was as "fast" as thought it would be, (I had expected more brutality, and my expectations were quite high)

Stock Ls1s dont have brutal torque delivery to begin with. The plus side is they aren't dead at 4500 rpm like older stock small blocks. You could build a motor to be brutal at low rpms but i doubt it would improve the overall car.

DrBoost wrote:

pres589 wrote: I'm wondering what weight could be saved if an aluminum 5.3 were used in conjunction with a non-T56 manual trans. Which, I don't know, the 4 speed out of a mid-80's GM pickup perhaps... those have been talked about here, are cheap, and are plenty strong for a near-stock 5.3 truck LS. I think a serious change in rear gearing would be required after that though.

I thought the only manual trans that would bolt to the L-series engines was the T-56. Is that true?

Nope, bell housing is only 1 bolt off from the SBC, you can parts bin the clutch, some 3/4 ton LSx truck flywheel has the old style pressure plate bolt pattern and thickness.

The idea of a V8 Miata interests me greatly, but I have to pass an ODBII based emissions inspection with one. How are people making them smog legal?

If you use a production car harness or an E-Rod, they can pass OBD-II inspections. Our exhausts have cats as well. Not a problem. Other than California, of course.

So you use the harness out of the car the engine came from and patch it into the Miata? Sorry for the ignorance and I appreciate the info. All of the real modifications I've ever done have been do pre-OBD-II cars.

We use new harnesses from GM Performance Parts at Flyin' Miata. But you can use one from a donor car, they're pretty self-contained and very well documented. The Targa car ran on an engine harness from a 2002 Firebird until a few weeks ago, when I went to a GMPP harness along with the new engine.