mx5cartalk.com

So.. Im pretty well known for liking turbo's and ribbing anyone who has a modest budget and isnt saving up for a conversion. The numbers just don't lie, for every dollar spent you get way more power AND torque from a turbo than a blower and between 10k worth of turbo and 10k worth of n/a its laughable on paper.

-On Paper-

But on the road..

Look, as someone who has turbocharged dozens and dozens of MX5's (and dozens of other models) I know a thing or 2 about how good a 200kw well setup na/nb chassis is, but for a few days Ive taken a friends N/A NA6 build to perfect a few intricacies in the tune. This is a car put together for around the same cost as one of my base turbo kits (250whp, 7-8k) and makes 125rwhp. Not only does it have a sweet little engine, but the suspension and brakes are great and well balanced, it has 8" 6ULs with NT01's, Car Make Corns seats, 4.1 torsen, HD clutch, all of the nice oldschool switchgear and one of those sexy RS Products (kg works..?) clusters with revlimiter gauges etc which together make it a really nice car, along with patchy white na6 exterior (foot round patches of white missing revealing undercoat and various cracks in the paint etc) its just such a gorgeous honest, Japanese style build, original parts, nothing flashy under the bonnet (You would NEVER guess it has >50% more torque than an OEM na6 by looking).

So basically, this thing is as fantastic as a car gets, as a drivers car gets. All of the controls are classic mx5, beautifully positioned and sized, feel is amazing, brakes are strong, turn in is on point, but the 125whp high comp cammy engine is such fantastic icing. You can go from idle to redline before the needle has gotten 2/3rds of the way up the tach, the idle is classic classic 70's supercar and the blips on the downshift arent a gradual rise in rpm you expect, its just an explosion of intake noise and exhaust and in an instant you have gone 3rd to 2nd gear. You can hardly tell the engine is rising in speed its just an explosion of n/a glory. This morning on the way to work I was cruising down a bypass road next to a new falcon with 'GSBOSS" number plates who gave a few smug looks my way and when we came to the T intersection at the end I went 5th-4th-3rd-2nd-1st with instantaneous explosive blips between gears, crackles, and ended up next to him in the queue with the exhaust brap brap brapping away. I gave him a thumbs up, and he just didnt know how to react.


Anyways, I wanted to end my rant by saying that Ive never ever owned a turbo MX5, and my favourite MX5 I've ever dríven was my first one, which I had built to my taste and for me, which was also a 125whpish N/A na6.


How good is it?! I need to get a drive in a 70's 911, Miura etc to see if it is as good, I imagine its very similar feeling (except this one wont break, can be insured, etc etc)

Dann

Thanks for the post NitroDann, love the "its just an explosion of n/a glory" and "an explosion of intake noise and exhaust "

numbers just don't lie, for every dollar spent you get way more power AND torque from a turbo than a blower and between 10k worth of turbo and 10k worth of n/a its laughable on paper. - how true...

Dan, couldn't agree more and i think I also speak for nearly everyone who has dríven my car.Not sure what 106 RWKW is in hp but I just love the responsiveness,fluid power delivery and sound that i get.

Will have it back next week after having new HLA's and heavier valves springs put in as well as adding an Arrive CAI that will attach to my existing MX5 factory one.Will be really interesting to hear it then.

I know I could have had more power per dollar going turbo but I am still really satisfied with what I have ended up with and pleased to see you recognising these types of builds as in some ways they are more in keeping with the original concept/balance and make a great car even better.

Peter.

Are you talking about Brian's car?

I do remember your stripped out NA though...that was a fun drive and I was very tempted to build Apu into a similar NB (ITB'd) version of that, but turbo was easier / cheaper / lazier.

Nice write up Dann... Whilst turbos are great, there is something magical about a well balanced N/A car. The combination of throttle response, linear power delivery, the willingness to rev and that gorgeous sound of the induction at WOT makes for a thrilling drivers car. Power isn't everything and sometimes I feel the push to turbocharge numbs all the things that made the MX5 such a fun car in the first place.

I've had my big 4x4 in for panel repairs so I've had to drive around my 1.6 B-spec. It is such a fun car because the engine is light and the cams kick in at 5000rpm so it loves to rev and is just begging to be dríven hard. It makes the drive home enjoyable, even in traffic. A short blast down the freeway on ramp, past a couple of slow sedans, revving through a few gears, settle back to 100kph and you have a grin on your face and haven't risked your license.

My main reason for wanting to eventually just slap cams into my car is stealth.

Down here basically anything that needs you to touch the ECU isn't legal.
A turbo is pretty obvious under the bonnet.

Cams, compression, etc. pretty much invisible.



The main thing that holds me back is cost, the cams are ok, but once you add in new lifters (the SUB ones) and mainly the ECU the price really adds up.

Apu wrote:Are you talking about Brian's car?

I do remember your stripped out NA though...that was a fun drive and I was very tempted to build Apu into a similar NB (ITB'd) version of that, but turbo was easier / cheaper / lazier.

Yes Brians. What a car.

Dan's description is exactly what I'm chasing... throttle response is what I like too, and lovely N/A noises!

The few things I have done to my NA8 have made it close to how the NA6 revs, but after driving my old car again this week I realise its still not quite as nice. Not sure that the VVT I'll drop in will help with that but Dan's description of revving faster than the needle... I like the sound of that!

Such a shame Dann's old car is no more. Sure it was dirty and smelly, and wet when it rained...luckily it had the top on then...it really was a go kart for the streets. Throttle response was incredible and I have to admit, much more fun than a Lotus.

Dann next time I'm near Newcastle with the MX5 in the trailer I will call in so you can have a drive if my NA. Be interested in your feedback, maybe talk about a small turbo.....

Honda K Series
250-300 rwhp possible

Honda J Series
will nudge a K for it's money as well.

Honda F series go ok as well but hard to find.

all go in and go like stink.

oztrackdays wrote:Honda K Series
250-300 rwhp possible

Honda J Series
will nudge a K for it's money as well.

Honda F series go ok as well but hard to find.

all go in and go like stink.

My BP is over 200 whp... and thats only a 1.84 liter engine. With a 2.1L stroker you'd be up around the 250 mark which would be close to the K20 limits. K24 would be untouchable, but your talking lots more cc. The difference between a highly developed BP and K is that you could still drive the K on the street!

Honda have always made excellent engines and I was looking into putting in a K20 before I went down the route I did. As a race car, I'm glad I stuck with the mazda engine as it's nice to be able to run in a production class and develop it as a compete factory car. The MX5 can actually compete and win against other production cars under 2000cc like the Lotus, Hondas, Toyotas etc. Once you change to a different brand engine or slap on a turbo your in a different class against other less limited cars.

Damnit Dann I've been on the fence between a N/A or turbo build for ages and you had me seriously heading for a turbo build and now you have me back thinking about a N/A build again.

There is only one solution to the N/A vs Turbo dilemma, and that is to have one of each!

Only wish I could afford it. So many plans, so little money. Probably not going to do either while I'm using it for a 110km commute 3-4 times a week. So not only need to fund power mods but a daily as well.