IRTB's

[slammer]

By logic, shouldn't a free breathing NA system be better for the engine than a forced induction one?

Nope high revs destroy motors just as quick as high boost...so a low boost turbo /supercharger (6-10 psi) motor delivering 110 -130Kw will last a lot longer than a motor running at 7600-7800rpm pushing 80-90Kw

[Rob E]

well i don't think your gearbox, clutch, diff, suspension, or brakes would care whether the extra power is coming from a turboed or na engine!

Not really - torque is what kills things not power, and the same power level the turbo will be making a lot more torque.

If your concern is engine life (ie. cost) just go with a low boost turbo. There is no point really going stock engine + IRTB + ECU (3.5K +) to make 15hp.

If you want day to day drivability, again turbo.

If you go IRTB you will want Cams, light flywheel, lower final drive etc to get the best of it.......

[CT]

118 - 123rwkw from a Naturally Aspirated engine sounds great.
What sort of mods (and money) are involved to get those kind of numbers?

Every mod you can think of (and some you won't) plus $8k minimum to get it all done at a very minimum - assuming you are starting from standard.

[Andy Wana]

The price sounds pretty close to a well sorted turbo system too ...

[Boags]

What do you consider well sorted?

You can get a HKS kit for around $3K, bolt it on and drive around with a smile on around 6PSI. HKS is a respected brand and the kit is good. Add a decent ecu and tuning to that, $4.5K. Add custom intercooler piping and intercooler (DIY about $300) from a shop $5.5k. Dump pipe back exhaust $6k.

Then you have a weapon, pulling much, much more than 120kw. Those prices are retail also, halve that amount if you can source parts yourself and do the labour - which is what I did.

If the battle is KW/$, then FI is always going to win. If you specifically want a super responsive engine and can live with needing a mile of open road to overtake someone (which is about the only problem with the MX5), midly tune your car NA to around 90kw and enjoy.

I can think of a lot of things less enjoyable than an NA MX5, so it's not like it's the \"wrong\" option, you just have to figure out what you want for your $$$.

Boags

[Andy Wana]

Sounds like, pound-for-pound, turbo is the best option if I want more power and day-to-day driveability
What about the AVO kits (browsing thru MX5Mania's website now) for the MX5? How do they compare to the HKS ones?

*edit* I'll move this question to a different thread, don't want to go off topic here

[Boyracer]

I reckon people are getting a bit power crazy...my old NA race car with 1.8,Quads,cams and Motec was lucky to scape up about 90rwkw but I was still doing 1.08sec. at Wakefield.

When you get the big power you tend to loose a bit of the skill that you get when you learn to really drive an underpowered car quickly....have to remember,MX5s are more about the handling...it feels real good overtaking a $200k. Porsche in a $15k MX5.

The SE race car is fantastic and it's nice to put your foot down and feel the power but the old NA was just as much fun to drive.

These are the quads going on to Slammers car when I fitted them to my first MX5 race car.

[Okibi]

Mark Pakula posted these pics in another forum ... full credit to him for finding these excellent (i.e. sexy) looking engine bay shots of an IRTB system on the 5...

They're from ClubRoadster, the owner spent a lot of time/attention trying to hide any wiring.

[Boyracer]

And this was the set up on my other race car...

[Andy Wana]

Maybe the solution is simple enough for me.
Learn how to drive fast in the current NA8 stock setup.
Then learn how to drive faster with turbo/supercharger/IRTB setup.

[green_comet]

Those are the Fujiracing Quad setup..

I have got in contact with Jimmy who sells these kits, and i will be ordering a set once i sort out my new wheels. Seems to be a great little kit, and one of the only kits I know of that run off a piggyback computer.

[Matty]

Intersted to see how the Fuji kit goes. Keep in mind that our RHD cars have a brake booster in the way to deal with...

[Rob E]

one of the only kits I know of that run off a piggyback computer.

From what i hear the piggyback set up on the Fuji kit is more of a stop gap measure than anything else........i too am keen on the Fuji kit however will be going MSPNP before IRTB.

[Fatty]

[
Not really - torque is what kills things not power, and the same power level the turbo will be making a lot more torque.

.

sorry i meant torque... im not great with the technical terms and i always interchange torque and power - differnt things i know. maybe i should just say "grunt" to cover all my bases

[Fatty]

When you get the big power you tend to loose a bit of the skill that you get when you learn to really drive an underpowered car quickly...

i have heard a few people say this. but i dunno, i reckon i am learning a whole new set of skills with the turbo. i actually found it a lot easier to drive my car on a really twisty road before i put the turbo on. the turbo adds a whole new level of complexity to deal with.

i haven't had my car on a track yet tho so i defer to the experience of others who have gone from NA to turbo on the track cars. actually its a shame i didn't get it on a track before i put the turbo on, the comparison would have been interesting.