Turboing MX5

Archives of Posts to the NZ MX5 List back in 2001
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Lou Girardin

Turboing MX5

Post by Lou Girardin » Fri Dec 07, 2001 9:10 am

Hi Rowan,
Engine durability will come down to preventing detonation and keeping intake
temperatures down.
Engine internals are very over-engineered in both 1.6 and 1.8's.
I heard of 15psi being used without problems but your engine management
system must be spot on.Check the Miata Power Page list those guys seem to
have done it all!
Lou

Pete Bronlund

Turboing MX5

Post by Pete Bronlund » Sat Dec 08, 2001 6:55 am

Why put up with silly 'riceboy' turbo projects. Any engineer will tell
you the only time you'd use turbo technology is on an aircraft engine
where issues of altitude come into play and that turbocharging a car
engine is a sales gimmick.

Far better to go to a supercharger!!! That way you'll have all that
extra power right through the rev-range of the engine without any lag
problems of turbos. Do the right thing, after just look at what the big
giants of the industry have to offer i.e. Mercedes ( the SLK
Kompressor).

... end of rant
Pete

Matt Gunn

Turboing MX5

Post by Matt Gunn » Sat Dec 08, 2001 9:26 am

Hi there

Have forwarded your comments to the WRX AND EVO making madmen. They have
been waiting for someone to catch them out with their world beating
gimmick sleds for years now.

Have given Porsche a call as well , suppose we could see a change in
that poorly developed 911 thingy.

love ya work

MADMXV

Rowan Hick

Turboing MX5

Post by Rowan Hick » Sat Dec 08, 2001 10:35 am

Wow thats really really nice of you to call my project a silly riceboy idea!

Please discuss the engineering/theoretical reasons why I should put in a
supercharger as opposed to a turbo charger. I felt like writing a 2-3 page
response on the technical and practical reasons why I'm going the turbo
route, but from the sounds of it I can save all that effort if you've got a
really really good compelling reason (or 3) why the engineers in WRC etc
have got it wrong.

Forget about using the SLK as a yardstick we're talking motorsport here not
pulling away from the lights in Parnell. :)

Rowan
PS: I've got a twin turbo car, does that make me twice as silly ?

darryl

Turboing MX5

Post by darryl » Sat Dec 08, 2001 11:32 am

Hmmm, supercharger, always boosting from the second you start to drive,
thats good for ecconomy! At least with a turbo you can drive it off boost
(pity our 20B Cosmo is twin turbo, hard to drive that off boost when
accelerating).
You are right Peter, I guess Toyota (one of the biggest manufacturers in the
world) have it all wrong, I mean, how stupid is the TT Supra, GT4 Celica's,
MR-2 Turbo's, Starlet GT, Soarer, Chasers, Aristo etcetcetc (oh, have sen
how slow those supercharged Levin's are??).
Then Mitsubishi, VR-4, EVO 1, 2, 3, 4, 5, 6, 7, GTO, Eclipes etcetcetc
Then Mazda with the RX-7 S4, 5, 6, 323 turbo GTX's and GTR's, Not to forget
the new MX-5 Turbo thats being released in OZ soon with 145kw,
Oh then there is Subaru with the ever so unsuccesful WRX, I mean, whats a
few world rally championships worth anyway.
Then lets not forget those other small time players like Audi, and Saab
(shit, don't Saab have it allwrong putting a ricy hairdryer on all of their
cars!).
I guess Bugatti should remove those four turbos from their new 1001HP weapon
and put a dirty great 6/71 blower on the top of it.

Haha, just proving a point. I think any new thing you can add to a Merc will
cause the yuppies to go goo ga and buy it so that car hardly rates.
Turbo's have their place and race cars are one of them.
We have a 4/71 blower on our 13B in our RX-7 (purely for wank factor and to
be a bit different, oh, and its going into the missus car) and it will never
put out the power (and have the same fuel ecconomy, if thats what you can
call it) than a turbo.
Besides, with a turbo, you want to drive it quietly, drop the boost back, no
need to change pullies.
Sales gimmic??? Works for me and millions or other people, guess we
are gullable then.
get the point?

Gary Morrison
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 100
Joined: Sun Jun 04, 2006 3:24 pm
Location: Wellington

Turboing MX5

Post by Gary Morrison » Sat Dec 08, 2001 11:44 am

Pete,

Go to www.miatapower.net and sign up for a week or so. Post your
supercharger comment there, and then run for cover.

Gary

Fletcher Blades

Turboing MX5

Post by Fletcher Blades » Sat Dec 08, 2001 2:48 pm

I'm not sure I can see any advantage in getting a GTR or GTX engine
over an MX-5 one if you are going to re-build it...

MX-5 uses the same block, with the under piston oil-squirters and
all...

MX-5 rods are not quite as bulky as the GTX ones... but they are the
Mazda specified replacement for GTX ones, as they are good enough and
the originals are no longer available... And if you are REALLY going
to build it up you'll be replacing the Mazda ones anyway...

MX-5 does run higher compression pistons... but if you're re-building
you can put in whatever pistons you like...

GTX does run slightly different exhaust cam timing, but its the same
duration, so you can just put an adjustable pulley on the MX-5
camshaft...

Also, I've been told that if you just try to drop the GTX engine in,
the turbo manifold faces more downwards (as opposed to after-market
MX-5 turbo kits) and this tries to put the turbo through some of the
engine-bay body work. The intake manifold is also facing the wrong
way, and the distributor will require a hole in the fire-wall...

In short, you have to do enough custom fabrication to make it fit,
that you may as well just do it to the MX-5 engine anyway...

People in the states seem to be running up to 14 psi boost on stock
internal 1.8 MX-5s (9.0:1 Compression Ratio) with no reliability
problems. I'm not sure how far they're boosting the 9.4:1 CR 1.6
engines... 12psi I think? These cars do eat the small 1.6 diff
though...

If you want to go higher than that, lowering the CR is definitely
advised...

I've been a passenger in a 1.6 MX-5 running 1bar boost from an AVO
kit... man that thing was fast... but they kit got sold to
overseas before the owner left NZ...

Theres one guy in the states running about 400 HP @ 22psi... but he's
on his seventh gear-box!

Its not for me though, I'm a NA man...

Fletch.

Sam Parker

Turboing MX5

Post by Sam Parker » Sat Dec 08, 2001 4:12 pm

Superchargers certainly give beter driveability - less lag that is why the luxury car manufacturers like Jag and Mercedes use them . The supercharged Jag 4.0-litre V8 is a thing of joy to drive - instant power whenever you want it and a very satisfying supercharger whine to tickle the auditory senses. However the supercharger does require engine power to drive and can only boost up as fast as engine revs rise so turbos give the ultimate in top end power and performance.
Superchargers also have an advantage for getting off the line with their instant boost - this is why the drag racers still stick to superchargers.
With good design turbos can overcome most of the throttle lag - especially the low pressure turbos used by the likes of Volvo and Saab - these are quite small so produce full boost at low engine speeds - makes a 2.0-litre 4 cylinder feel like a 3.0-litre 6 to drive.

Regards

Sam & Denise Parker
340 Beach Road
Mairangi Bay
Auckland
NEW ZEALAND

Ph/fax 64 9 478 4761
Mobile sam 021 909 140, Denise 025 774 917
email samparker@clear.net.nz

Rowan Hick

Turboing MX5

Post by Rowan Hick » Sat Dec 08, 2001 6:06 pm

This too can be solved in turbo world.. I run the Racelogic Traction &
Launch Control system in my Z... I can have 0.2-0.4bar boost whilst sitting
with clutch in ready for launch :) - Just incase people are wondering how
you have a secondary hard cut rev limit... mines set at 5500rpm, full
throttle bouncing off the limiter produces enough energy in the exhaust to
start the turbos spinning :)

Horses for courses at the end of the day. If I wanted a low down torquey
round town car I would put a supercharger in it but thats not my goal. Targa
is at the end of the day what I'm aiming for :)

Rowan

darryl

Turboing MX5

Post by darryl » Sat Dec 08, 2001 11:26 pm

What got the 'unofficial' overal win in targa this year, and second the year
before, and 1st in class the year before that?? A turbo Mazda RX-7! A S6
Batmobile that has a single turbo too!
The big V8's still use superchargers for the same reason they use mechanical
injection, fear of technology! Look at the Puerto rican's running very low
7's (apprently one of the RX-7's just ran a high 6??) in little 1300 and
1950cc rotaries. They wouldn't have been able to do it with a supercharger
sucking power and acient mechanical injection!
Superchargers have their place, but turbo's are best for all round
performance.
Why else are there only a couple of companies making supercharger kits for
MX-5's compared with all the turbo kits out there, HKS, TRUST, AVO etcetc

Rowan Hick

Turboing MX5

Post by Rowan Hick » Sat Dec 08, 2001 11:36 pm

Tomorrow I'll put up my reasons on 600plus.com for going to the GTR block,
from all what I've read there's quite a few trick bits in that engine that
makes it a very very good choice - it'll all depend on if I can find said
engine at the right price. Buying all the bits in one engine does actually
save you a lot of time and hassle on sourcing things like fuel injectors,
turbo etc.. sure it's pot luck as to how good it is but if you win you win
big time :)

Rest assured I'm not putting a hole thru the firewall, nor in the engine bay
bodywork. The dizzy will be replaced with a crank trigger and some bosch
coils. And if necessary on the turbo front a custom manifold will be made
up.

I just really need to get in touch with those guys that have already done
the conversion and see what they've found out, no sense reinventing the
wheel!

Rowan


[...]

darryl

Turboing MX5

Post by darryl » Sat Dec 15, 2001 12:20 pm

why's it take so long or some messages to come through?/ like after the
topic is almost dead??

Pete Bronlund

Turboing MX5

Post by Pete Bronlund » Sun Dec 16, 2001 9:30 pm

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