Turbo - 1600 or 1800?

[Marf]

Hi All

I'm thinking about trading in my MR2 Turbo for a cheap daily diseasal and possibly an MX5 to run as a weekend toy with a view to turboing it.

Would people recomend going for 1600 or an 1800? I'd probably be buying a spare engine to rebuild in order to keep the car on the road as much as possible.

Thinking along the lines of forged pistons, MLS gasket, some suitable 264 cams and a GT25 turbo, proper standalone management etc.

Outright power is not really my goal, I just want a nice revvy engine with a linear torque curve from a responsive turbo

Cheers

Marf

Edited by Marf on Tuesday 12th April 10:51

[Richyvrlimited]

Marf said:

Hi All

I'm thinking about trading in my MR2 Turbo for a cheap daily diseasal and possibly an MX5 to run as a weekend toy with a view to turboing it.

Would people recomend going for 1600 or an 1800? I'd probably be buying a spare engine to rebuild in order to keep the car on the road as much as possible.

Thinking along the lines of forged pistons, MLS gasket, some suitable 264 cams and a GT25 turbo, proper standalone management etc.

Outright power is not really my goal, I just want a nice revvy engine with a linear torque curve from a responsive turbo

Cheers

Marf

Either will suit you then, though the 1.8 cars have more under body bracing, larger front & rear brakes and a much tough differential. The 1.6 diffs can pop with stock power.

If you're not chasing big power shelve the built engine plans, their pointless. Cams are even more pointless unless you seriously improve the heads breathing power - there are guys in the states pushing nearly 400bhp at the wheels with the stock cams.... If you're desperate for them realise that the stock head breaths terribly and you need to massively improve that to realise any benefit, that means a custom intake manifold and lots of headwork, preferably done on a MK2 1.8 head which is far superior to the MK1 head.

Also note that the stock pistons are generally fine, only change them f you want to drop/raise the compression ratio. The rods go first, they tend to bend, so uprated rods should be first on your shopping list well before pistons, similarly the 'uprated' head gasket is not really required. The OEM gasket works fine on high powered engines, it's not a weak point by any means.

Note that the stock engine is good for an extremely reliable 250 - 280 bhp assuming it's well supported by a good tune.

Edited by Richyvrlimited on Tuesday 12th April 11:19

[Marf]

So really an 1800 would be a better base, and just wang on a turbo kit and Roberts your mothers brother?

Will a stock engine last long on 1bar?

I'd want to retain AC as well, is that possible when fitting a turbo kit?

My thoughts on a rebuilt engine were more along the lines of "I want to give it death, I'm not sure I trust a stock engine to cope with that".

Edited by Marf on Tuesday 12th April 11:27

[Richyvrlimited]

Marf said:

So really an 1800 would be a better base, and just wang on a turbo kit and Roberts your mothers brother?

Essentially yes, look at FlyinMiata's kits, or the re-badged BEGi kits by BBR.

Marf said:

Will a stock engine last long on 1bar?

Assuming it's well tuned and serviced regularly (i.e. 5k oil changes on synthetic), It'll last as long as a stock car. Tuning really is the key though, ensure you have good engine management and it's properly tuned.

Marf said:

I'd want to retain AC as well, is that possible when fitting a turbo kit?

Yes

[Marf]

http://www.flyinmiata.com/index.php?deptid=4525&am...

http://www.youtube.com/watch?v=uC3o5jc1Ck0

Nice

[Richyvrlimited]

Marf said:

http://www.flyinmiata.com/index.php?deptid=4525&am...

http://www.youtube.com/watch?v=uC3o5jc1Ck0

Nice

No engine management or larger injectors with that one, so factor those into the cost aswell.

But yes properly rapid

[Matt UK]

Would it not be much cheaper to buy a good turbo car in the first place?

[Marf]

Probably yes, but I've currently got an MR2 Turbo, other 2litre turbo options include 200sx, Impreza, EVO.

200sx Doesnt float my boat
Impreza too expensive to run and insure
EVO ditto

Always had a soft spot for MX5s but would want more power, hence looking into turbocharging. Plus it would be my second car, and I've got a hankering to undertake a project

[MX-5 Lazza]

He meant, why not buy an MX5 that's already had a turbo fitted

[Marf]

Doh, coffee hadnt kicked in

That is an option, but I'm a very fussy car buyer! I like to buy standard and upgrade.

I'd want to retain AC, and it seems most people ditch it rather than working around it.

I wish I'd had the money to buy the Mazdaspeed Factory Supercharged car that just sold in the classifieds, that looked like a proper little beastie.

Edit: nice car BTW

[trackerjack]

What you want is exactly why I bought a Mk1 in the middle of winter and found a turbo engine in a professionaly built kit car racing chassis.
I was going to take the engine and sell the chassis.
However I am now building my third kit car hmmm.
I have still to drive the MX5 I bought but am changing the rear broken springs today.

[iguana]

Marf said:

Doh, coffee hadnt kicked in

That is an option, but I'm a very fussy car buyer! I like to buy standard and upgrade.

I'd want to retain AC, and it seems most people ditch it rather than working around it.

I wish I'd had the money to buy the Mazdaspeed Factory Supercharged car that just sold in the classifieds, that looked like a proper little beastie.

Edit: nice car BTW

I might have a car that could suit you, 1.6 with a JRSC charger & lsd, other than that is pretty stock, so you could fiddle & make it what you want.


I've also got a cracking track modded Mazdaspeed 1.8 but not looking to sell that at the mo.

[Marf]

Sounds good but I'm not in a position to buy yet. Priority one is selling the MR2 and buying a diesel.

What kind of power would you expect from that setup?

[iguana]

Not big numbers really, most folks say the basic 1.6 SC set ups are 160bhp ish, Mazdaspeed quoted 180ps for my 1.8 when it was new, so circa high 170s in horseys is which feels about right & is what that fella with the silver one got on the rollers, with other management, intercooler, bigger injectors, smaller pulley etc etc then are a good few 200+ bhp m45s.

Have a look on Nutz for more info.