mx5cartalk.com

That's right kiddies,

I've been doing some investigations with the DoTaRs for my new car and it looks like thae changes to light car modifications may well allow rotary fans to legally fit a 13b Turbo to an MX5

Approval under Code LA1 allows for \"Fitting of replacement engine with not more than 20% greater weight and or power than engines offered by the first manufacturer as a standard or optional engine.\"

Then it must fit into teh following equation (for vehichles between 800 and 1100kilos)

Original weight in kgs x 2.5 = Max capacity in ccs.

\"The engine capacity used for rotary engines is twice the swept volume of all rotarts\"

What this means is a 13b has a \"capacity\" of 2616cc.

So working with the formula:

Weight(kg) x 2.75 MUST = 2616 (cc)

So weight MUST = 2616/2.75 (or more)

So weight must equal 952 or more....

Now an NA weighed from 940 to 990 dependant on year model and options, so SOME NAs would be eligable.

NBs weighed just over 1000kg, so they are definately in.

Then you need to meet emissions requirements, the engine must be newer than the car and comply with ADR emissions standards ADR 37:01.

A series 6 onwards RX7 will comply with these ADRs, as long as you get an engine/frontcut from an RX7 newer than your MX5.

There are a few other bits and pieces that'd need to be worked out but it looks positive for rotarians

Not sure how we'd go on teh powe not exceeding an additional 20% of the original, but definately go for NBs who had teh SP as an original mazda variant


Oh and NO, I'm not building a 13bt mx5.

Yay thats good news

My 1520kg Luce goes pretty hard as it is, so with 550kg less an NA would be bloody frightening

BTW, my NA weighed in at 1040kg with a full tank of gas (incl Brown Davis, etc etc) and the S6 13BTs are quite different from the S4/S5 ones. Eg it's actually a big job to put a S6 engine in an S5 RX7 because the mounts on the block are different...dunno if it would make it easier or harder to install in an MX5 tho...

your crazy sean

Thats Great news sean!
the Bad news is no one on this site has the balls to do it!
what a shame!
I advertised a whole conversion for $3,000 including an engine, computer and ignition system.
no one bought it so i separated it...
A s6 engines are way better than s4/5 13bs, not sure bout fitting one to a s4/5 but changing the front cover to a 12a type and it will fit into anything with a front mounted crossmember,any early mazda etc...

Duj wrote:Thats Great news sean!
the Bad news is no one on this site has the balls to do it!
what a shame!
I advertised a whole conversion for $3,000 including an engine, computer and ignition system.
no one bought it so i separated it...
A s6 engines are way better than s4/5 13bs, not sure bout fitting one to a s4/5 but changing the front cover to a 12a type and it will fit into anything with a front mounted crossmember,any early mazda etc...

errr i know 1 person does.....hold on thats you.


10years ago i started asking about turboing an NA (before kids).....general answer was.....no one here is really set up for it for the tuning of it & so on. They were doing it a bit in the US & Japan at that stage.

I have a feeling, thats where the rotary convesions are up to at the moment. Although a few conversions have been done. I feel you are really still at the pioneering stage of rotary conversions. It could be....that your conversion kit is just a little ahead in its time. I wish you good luck in the sale.

What about emissions laws? From memory you can't install an older model of engine in a newer vehicle because it doesn't meet emissions laws.

duj, why didn't you keep the kit and use it on your car?

sabre- I was going to use it on my car but it already has a decent 12at and is too fast as it is
more people need to do this conversion!
awesome power, just rolls on beautifully
I have a pic of my new setup with water2air IC if anyone wants to see it/host it for me?
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duj: ahh, I see. If you want an image hosted, go to http://workshop.sabretooth.id.au/imgupload.php. Give it your image URL (remembering to remove spaces from it first) and it'll do the rest.

apsilon wrote:

sabretooth wrote:What about emissions laws? From memory you can't install an older model of engine in a newer vehicle because it doesn't meet emissions laws.

That's what I was going to ask.

Also when I looked into it way back there was also an additional factor for turbos. Is that no longer the case? At the time I could've fit a 13b no worries but the engine was considered to be too large if it was a 13bt. I ended up just doing a turbo kit on the original engine.

Like I said above, the 13b would need to be series 6 onwards to comply with ADR 37:01 which is emissions, the newer the recipient car, teh newer your donor car will have to be.

As for the turbo multiplier, that's considered in the formula:

Original weight in kgs x 2.5 = Max capacity in ccs.

If the car is remaining NA then you replace the 2.5 with a 4.0.

Original weight in kgs x 4.0 = Max capacity in ccs.

Which means it could technically be legal (if possible ) to drop a commodore V6 engine into an MX5

Well, it sounds farkin' good all this, but, think of all the beer that money could get ya.

I am thinkin' about doing something to Bene along the lines of turboing the thing or sticking a rotary in it.

I will be reading these threads with interest...

interesting indeed.

my NA is factory quoted at 950kgs.

do they (rta) go on that or your actual weight?

im semi thinking of engines for my car..
and i reckon id want something NA, lighter than stock, and about 140rwkw

renesis or f20c seem to be at the top of the list:P

so is anyone SERIOUSLY going to do it? 13bt?Renesis?
or shall we just wait for the next MX5/ROTOR thread in a month or two so we can all say \"yeh im thinking bout it\" again?
would love to see more rotor mx's out there!

would love to see more rotor mx's out there!

Me too, sorry Duj would have bought your kit but ended buying a boat instead now me broke

Was talking to a mate whose got a 20b cosmo, he said queensland roads didn't know how to class it so its registered as a 4 cylinder

Not a bad 4 cylinder upgrade for an MX I say, pitty about their weight.

lol, nice question
Its really suprisingly quite good! ,
I can go for a massive cruise all night long on $30 worth of Bp Ultimate (all i use) and thats usually $1.40/$1.50 a litre and still have petrol left the next day
when im cruising its ok, il do a check once its back on the rd
from what i can remember my old 1.6 NA would really drink it when i was thrashing through the hills and revving out gears, the rotor doesnt need to work as hard, so thats why i think its better
peeps probably wont beleive me but its true!,