18 replies to this topic

[Gilly112]

(Specifically for a mini..)

 

On the turbo minis website, its stated that 130hp is easily achievable through a few modifications to a metro turbo engine, which I have. However, being the first rebuild/project I've done, I'm wondering whether swapping for a supercharger would be the way to go in terms of reliability, ease of set up etc..

 

I've read about mpg going down and the benefits/drawbacks of blow through and draw through, but will 130 bhp be a reasonable goal for a supercharged metro turbo engine? If not, it's not going to be for me!

 

I'm not interested in selling the turbo before anyone asks, if I did, it would be after I've lined up a SC or in an exchange for a SC.

 

I'd be interested to see anyone's pictures and listen to opinions of people with turbos and superchargers!

 

Cheers

[welshdan]

once you go turbo you will never go back...

 

its a fairly straight forward install, you can control boost with your right foot so that it could be driven as an na mini by keeping it off boost with a t3.

 

also easy to extract the power that you are looking for.

[bigmatt4]

way i see turbo vs supercharger is with a supercharger you lose power (driving the charger) to make power where as a turbo you dont and turbo pressure is easyer to adjust also suck through is better than blow through because you dont have fuel pressure issues thats just my 2 cents

[Rog46]

No lag in a supercharger

[psychobob]

you would think a supercharger would cause less wear on the gearbox and diff as its constant power, rather then the shock of the turbo cutting in?

[Gr4h4m]

Never driven a turbo mini. My supercharged mini just feels like it has a bigger engine. I like it for all it's inefficiencies.

Turbo is the way to go for the most power.

Boost is addictive....

[benjy_18]

Having driven both super and turbo charged engines (in other cars!) I would say it differs massively on what you want the car for!

If it's a track toy then turbo, if you want genuine drivability then supercharged is easier.
However a turbo engine can also be very good on the road if you run a sensible amount of boost. If I were you, I'd stick with The Turbo engine you have and just carry out a few basic mods then up the boost to around 10-12psi.

[Rog46]

If it's a track toy then turbo, if you want genuine drivability then supercharged is easier.

I would have expected supercharged to be better on a track with no "turbo lag" (I've never driven supercharged , just interested)

[Cooperman]

It's personal choice really. Both have their advantages and disadvantages.

 

A supercharger will give less ultimate power, but will have no lag. It will, as above, just make the engine seem to have more capacity. It takes some crankshaft HP to run it, but it can be geared easily and will/should be very reliable if installed and set-up correctly.

 

A turbocharger will have the ability to run high boost pressures, and thus give more ultimate bhp, but they run at ultra-high temperatures and the maximum boost must be set correctly.

 

A supercharger is usually more mechanically reliable than a turbocharger and it is easy to set the boost using different drive cogs. With modern toothed belts belt slip, which used to be a problem, is no longer an issue.

 

There are some cars which run both.

[Pete649]

 

 

 

 

There are some cars which run both.

 

You beat me to it. I was going to say:-

 

Both?

[Cooperman]

I did a lot of calculations for a 1275 Sprite which was to have a Shorrock supercharger fitted. I geared it to give a 1.3:1 blower speed over crank speed and it worked very well once it had the correct needle in the carb. Power was smooth and higher over the full rev range, torque was also better across the rev range and there was no lag. For an improved road car it seemed ideal.

However, a turbocharger would have given more maximum power, but within a narrower power band and with some lag. With a turbocharger you need to keep the revs up to get continuous power improvement, but there is more max improvement than with a supercharger.

Let's not go into 2-stage superchargers as that is very complicated and I don't fell qualified to comment on how they work.

Remember, the Spitfire, Hurricane, Mosquito and Lancaster all had superchargers and they worked well (ask the Germans  ), but the American B17, B24 and P47 all had turbochargers, which, incidentally, were often referred to as 'Turbo-superchargers'.

[Pete649]

IIRC didn't the Spitfire have a two speed supercharger but German technology of the time had variable speed superchargers? And fuel injection instead of the Merlin's carbs.

[Cooperman]

The Spitfire had a single speed supercharger until the Mk.9 was introduced. That had a 60-series Merlin with 2-stage blower. The second stage cut in at around 24000 ft and it was like a good 'kick up the proverbial' and the thing then went much better than the FW190, which was the Kraut 'hot-ship' of the time. The P51 Mustang had a 60-series Merlin which made it a true Anglo-American aeroplane, much as the Yanks don't appreciate this (but I love to tell them about it  ).

The Krauts had direct fuel injection which meant that they could push serious negative 'G' without the engine cutting out, but a certain Miss. Shilling, an engineer from Farnborough, designed a restrictor plate to stop petrol surge in the carb float chamber (it was known as 'Miss Shilling's Orifice!).

I don't know whether the Krauts had variable speed blowers - I'll look it up.

 

Look at all the useless information you can get on TMF!

[madaboutcherry]

http://www.gizmag.co...the-year/15542/

 

[BlackJester]

I am guessing supercharging and turboing isnt an option?