turbo and super chargers

[Vart]

how hard are these to fit? not for a specific charger but basically.

how dramatically shortened does engine life before also?

thanks

[5lab]

to a 340 you are best just replacing the engine with one from a 400 turbo - it bolts in fairly easily i think - huskyracer has one. or get a renault 19 16v 1.8 engine - loadsapower.. fitting a turbo is possable otherwise, but its not entirely straightforwards..

[Black_360_GLT]

You could pick up an Eaton M45 supercharger from the new Mini coopers for under £150, fitting it would be another matter though. You would need custom mounts made and pulleys etc, and it would have to be set up by someone who has experience with fitting and tuning engines. If you run one at standard boost they will give you about 20-25hp more, up the boost and you are talking +35bhp ish.

Superchargers have some benifits over turbos, they put less strain on the engine, the power band is more graduall - so less wear on the engine and there is also no lag - a fundamental problem with turbos. They also dont increase the engine temperature as much as turbos. One thing that needs doing is a refurb on them every 50,000 miles though, which can be costly.

When you fit a turbo you have to do many mods, like bring the compression ratio down, on the engine in qusetion it would have to come down quite a bit, most turbod engines run compressions of around 8.x.x some people fit different head gaskets, use low compression pistons, heads etc. Then you have to make a custom exhaust up, usually at least a 2/2.5bore if its a turbo and you will need a custom manifold also.

In either scenario you need the money, skills and parts to do it, its far more simpler to swap your engine for a turbo unit as 5lab has said or stick a bigger N/A engine such as a 2liter renault unit from a 440/460/480. The Renault 1.8 16v engine found in the Renault 19 and clio is very tunable and has 137bhp stock, thats more than a volvo 2liter, Renault 1.7turbo or 2.0. There are even 2liter bore kits and turbo kits for those 16v engines which can produce in excess of 220Bhp. Also there is rthe Williams 2.0 16v engine which is the same as the 1.8 16v but has better head porting and bored out an extra 200cc - so it produces 150bhp which would make a 340 fly. Im not sure if you would have to uprate the driveshaft for that level of torque.

Hope this helps a little.

Regards,

Al

[Vart]

i see

it was more a query than an intention. superchargers only appeal cause i think a supercharged 340 would be pretty interesting and no one seems to have supered a 1.7. yet.

50,000 more miles and i think the 340 would be rusted too bad anyway. my '85 DL is in much better nick apart from choke than my '89 1.7 GL. i think i should have inspected it more throughly upon purchase.

i was thinking supercharging with a vanishing point style supercharger, minis aren't real cars anyway.

[Black_360_GLT]

You cant put big superchargers on small engines mate, they are meant for Yank tanks and cars with big cc displacement. You would be suprised how well the supercharger mod on a 1.3 mini is, 130bhp in a car that weighs nothing.

Regards,

Al

[Damir130]

they put less strain on the engine

How do you see this? Why exactly would a supercharger produce less strain? The engine has to turn the supercharger as well, that means a peak horsepower loss of up to 20%. Horsepower (and heat) that the engine is producing, but that never arrives at the wheels.
Eaton superchargers als produce a fair amount of heat at high rpms, more then an equivalent turbo setup with proper intercooling.

In short a turbo is always a better choice if you don't have to have instant throttle response. they put less strain on the engine, produce more hp at the wheels and make the engine more efficient.
Superchargers are real torque multipliers making for a rocksolid powerband and hooligan like driving behaviour. They do put more stress on the driveline and are sensitive to knock; Both due to the high torque in the low-rpm section of the powerband.

[btw, I like sc's myself, just trying to prevent misinformation. Converted a single cylinder carb engine to autorotor SC + EFI for our FSAE team. 50% rise in hp despite an intake restiction from 40mm to 20mm (class-rules)]

[Black_360_GLT]

I think the website below weighs up the pros and cons of superchargers fairly.

http://www.superchargersonline.com/content.asp?ID=19

Regards,

Al

[huskyracer]

Interesting one this! In my opinion, turbos are easier to install, and make more power. Superchargers are very good (positive displacement types, IE rootes) but are difficult to fit, due to the mountings/ brackets you have to make. All the brackets must be very stong and the belt run MUST be 101% perfect, as the supercharger can use upwards of 40 horsepower, all that power has to be transmitted through the drive belt. If the brackets/mounts flex or the belt is not perfectly aligned and tensioned you will throw belts off, loose boost through the belt slipping etc. you will have to lower the compression just as you would for a turbo as well. (anything that creates boost requires lower compression, unless the boost is kept very low) also with a supercharger, you have to throttle the air before it enters the charger because it is mechanicaly driven. If you throttle it after the charger then the first time you shut the throttle from a reasonable rpm you will most likely end up with a very bent throttle plate as the boost has nowere to go. this is why production cars have a bypass system, shut the throttle and boost is directed back into the air intake. Intercooling is very important when using a supercharger such as a rootes/eaton type, they can easily make in excess of 100 c intake air temp, more than most turbos! For the above reasons, intercooling is difficult, if you have the throttle on the back of the charger, when you open the throttle, the air has to go through the charger, through the pipes to the intercooler, then the intercooler and finaly the pipe to the manifold to get to the engine, which as you can see will cause a massive delay in the throttle response. with a bypass valve you can throttle after the charger, and use an intercooler without the drawbacks, but the easily avalible (ie mini/some merc's) superchargers wont have these and there expensive to buy.

Turbos require the refabrication/adaption of the exhaust manifold and exhaust system, and fitment of an intercooler, but usualy this is easier than mounting a supercharger. they make more power per pound of boost (and cash!) But I think they have aquired an undeserved reputation as an engine destroyer, due to people fitting them to otherwise standard engines without altering compression/fueling /ignition timing
Pleas note that these are only my opinions, but all of the above is based on things I have tried my self.