WANTED!! 100+ rwkw in an NA nb8a daily

[sliq]

so who do we go to, to start placing bets?

[RG.net]

with that i would expect 120-130rwkw

I think that is very optimistic. Even if you tuned on Mania's dyno.

we'll see what happens i think it is achieveable, i'm not going with mania, never grew fond of them. But as i stated, not much information is avaliable on N/A mx-5's, compared to F.I, so for me, or anyone else that is treading in the depths of N/A dont have a clue on figures, its really hit and miss after the basic cams/ecu/exhaust and intake setup.

[16bit]

with that power target you are going to spend an absolute fortune. stroker motors are farkin expensive as well as irtb's. you want a built na motor that you don't care if its streetable or not (which yours won't be very nice on the road) get a proper race motor done by gary stewart or someone like that. they know how to make 140rwkw plus for the race guys. not cheap though. I spent 8500 dollars on my supercharger setup and I have stock drivability with about 160rwkw. You will spend a great deal more to get less power that is much less reliable and drivable. respect if you can do it but it will be a long costly experience.

[philz]

Stroke the engine to 2L, ITBS, full headers and exhaust, stand alone ECU.

What a machine it will be, not to mention how much money it will cost.

[Woo]

If done properly there isn't much difference between NA and FI (except the kW and Nm).

Look for the area that has the greatest potential as thats where you get most of your improvements.

From experience we know it's not difficult to get more fuel in but to take advantage of that fuel you need air and spark.
Spark is relatively easy, try a search for COP or look into MSD systems. Fuel quality also plays a big part, if you build it to suit 110 octane then you can always tune it back for 98. 110 also allows you to run more timing, more timing generally means more power. Then there is air ..... man is that a COW

Start off with your desired compression ratio. If you only ever run 98 you can get to 13:1 with a good (read great) tune. You can get 15:1 out of 110.
So now you have high comp pistons (Wiseco), carillo rods (or similar, I like Argo for FI) to be able to handle the high comp pressures. Now it's a case of getting the air in there and out again. NA it's not easy as there are loads of variables.

When I did my head developement we found that the greatest restriction in the intake (FI or NA) is the throttle body. There is a physical limitation as to how much air you can flow through the TB area. Sure you can squeeze a little bit more air into the chamber with bigger valves but at the end of the day it's the TB holding you back. Add to a bigger TB a free flowing RAM CAI (not just a CAI, use the force of the air to give you that extra boost) and your now getting enough air into the valve area. Throw in some bigger valves (FM do some reasonable units), springs capable of 9000 rpm, titanium retainers, then get the head flowed for where you want the torque (cough cough I mean power ).

The maximum lift you can get safely on an NB cam is 11.8 mm until spring bind. Keep that in mind when choosing cams. Cams aren't my forte as FI is very different to NA. Some of the NA guys will talk at length about overlaps and durations. Me, I just throw in another pound of boost or two.

Then there is the exhaust, another COW's. Many people will say you need a small amount of restriction in your exhaust to provide back pressure. Wrong!!!!
Back pressure causes reversion (the charge gets forced back into the intake). The exhaust and the cams have to be married to each other and generally cost 10's of thousands to set up properly.

Then there is the all important aspect of reducing reciprocating mass and balancing, balancing, balancing (yes it should be done 3 times. Crank, flywheel and rods)
I've seen 400 HP from a 1.8 lt (albeit Nissan) with this philosophy, so imho there should be no reason ($$$$ excluded) why the BP cant do similar. After all its just a heat pump

Cheers
Bazz

[MXcrazy]

hmm, well Mxcrazy has 92 rwkw on the mania dyno with 2.5" exhaust and the mania intake.
I could see that reaching 100+ with cams and ECU.
I wonder how much of it comes down to the individual engine tolerances, lots of stock cars seem to get different values

Even if it may be "optimistic", i belive I could get over 100rwkw with A standalone ECU, cams, and a decent tune.

[Novice1]

I, second 16bit's comments re contacting Gary Stewart. Naturally aspirated engines are his forte. I, think if you talk to some of the race guys they will back this up.
Cheers Novice1 aka Ron

[greenMachine]

I, second 16bit's comments re contacting Gary Stewart. Naturally aspirated engines are his forte. I, think if you talk to some of the race guys they will back this up.
Cheers Novice1 aka Ron

Gary built my engine, my only regret was that I couldn't afford a new ECU at the time ... my pocket hurt but it was money well spent as far as I am concerned .

Oh, and if you get cams, buy billets, the built up ones I had didn't last the distance covering lots of road kms as well as the competition kms.

[neil d]

I'm sure CT will pipe up soon however until then my Na race car had between 120-130Kw at the bags however to get that it cost well over $8000 on the engine alone. The biggest restriction on the BP motor is the head flow and intake restriction. It is simply not designed to flow over this power. You don't need bigger valves to get the 120kw but you will be running upwards of 11:1 compression and will need a bigger cam than you have listed. These mods will make it less desirable to drive on the street however Cal does drive his race car on the street to local meeting so it is possible.

Good luck with getting the power as they are allot of fun with more squirt, best advise I can offer is speak to the likes of Gary Stewart who has built about 90% of the mx5 race engine in QLD including mine and Cal's on the forum as he knows these engines inside and out.

Neil

[16bit]

as stated above the bp is just not designed to be an na monster. with the money you are looking at spending and your intent on remaining na wouldn't it be best to look at an engine conversion to something that is designed to be an na monster. I am thinking f20c. its been done and you will be able to get huge power (considering na) and there are heaps and heaps of parts for it.

[CT]

Should do - but it's going to be a pig to drive if you go much more. To make an MX5 engine make above 110rwkw (dyno dynamics shootout) you need to convert to solid lifters and remove as much rotating mass from the engine as you can (crank, flywheel, rods, pistons). You need at least 11:1 compression and you need big, high revving cams - 290deg plus durations. A stroker kit will do it easy but man, what a massive cost for really small gains. At 125rwkw, my car idled at 1300rpm. Think about that at the traffic lights. Not to mention your head will need to be ported and flowed by an expert on a flow bench - a hack will stuff it up. My head flowed 280hp by the time it was finished and cost me about the same as building a new turbo motor - and that was with standard sized valves to maintain high airflow speeds.

If you search, there's a lot of info on hipo NA motors it's just that those of us that have done them, realised that turbo power is much easier and cheaper.

i am confident i will crack 100rwkw with my setup.

this will consist of
ported/shaved head
thinner headgasket
oversized valves
stiffer valve springs/retainers
camgears
895c cams
piggyback ecu
2.5 inch exhaust
4-1 extractors
short ram intake

2nd stage will consist of

ITB's
rebuild bottom end/stroker kit
standalone ECU (itb's need a standalone to run on the mx-5)
bigger fuel pump
bigger injectors

with that i would expect 120-130rwkw, which i believe would be sufficent for a lightweight like the mx-5.

however there is not much information/conformation on NA MX-5's, most just save the hassle and go F.I

like others said, how deep are your pockets? F.I is definately easier and cheaper, but there isnt the cool factor like a N/A MX-5, if you do tend to go extreme, you will loose driveablility too which you dont want on a daily driver.

[Boags]

My head flowed 280hp by the time it was finished and cost me about the same as building a new turbo motor

[stevesports]

My head flowed 280hp by the time it was finished and cost me about the same as building a new turbo motor

i mean, what was your motivation to build something like that? was it for a racing series or something?

[Boags]

My head flowed 280hp by the time it was finished and cost me about the same as building a new turbo motor

i mean, what was your motivation to build something like that? was it for a racing series or something?

It was a race car Steve.

[CT]

My motivation was to compete against Porsche and Lotus race cars. At the time, the only NA car with more hp than mine was Brian's orange car with a big buck Yager stroker race engine. Compared to now, where my turbo car still has a stock head and cams and makes ridiculously more power than that......I wish I'd gone turbo earlier!