I'm going to boost the power of "she who must be obeyed"'s MX5 and was happily pursuing the supercharger route.

However when I contacted BBR who sell the cosworth supercharger conversion they advised against it suggesting the turbo option instead as it was "more efficient".

TBH when looking at a power boost I couldn't give a hoot about efficiency but perhaps there is a back story I'm ignorant about!

Both kits are about the same price can the collective give me some advice on how to choose?

I'm not interested in conventional tuning as SWMBO wants a driveable car that will tootle along or go like stink as and when she wants - Oh and it must be sorted hence kit I'm way too busy with other projects to take another ongoing saga.

Cheers!

PS its a 2.0 mk3 totally different to the mk1 & mk2

[Edited on 21-7-14 by v8kid]

If you want an overall power hike then I'd go Supercharger

Good torque/power boost and easily accessible (don't have to rev' it to get the power)

If you want max' power then a Turbo will do that better - as it is more efficient.

Good torque/power boost but it is more difficult to get to the power - she will have to rev' it a bit more.

That's all pretty broad brush stuff and prone to massive change if you do things slightly differently.

Now; where's the Tea and Biscuits? This is going to be a long thread

Ask the good lady, does she want a linear constant power or does she crave a kick in the back when she wants to get a move on?

I've always preferred a turbo over a supercharger in my tintops purely due to the fact the turbo surge has always brought a smile to my face, however a ride in a turbo'd kit scared the crap out of me and a supercharger would have been better. I suppose an mx5 being a lightweight-ish car it's a bit of a dilemma.

if I was more cynical I would say it's probably more efficirant as they have one gathering dust on a shelf and want to sell it rather than making up a supercharger kit...

id go turbo they are more efficient if they wasnt then we would all be driving small cc supercharged engines

i also dislike the noise of a charger but that up to each individual i suppose

Good review of the BBR Turbo kit on Pistonheads.

It sounds impressive; 0.5 bar boost and you get an extra 100 bhp, a load more torque yet peak power remains up at ~7000 so it still loves to rev.

The pistonheads report is a surprise! I thought turbo lag would be the problem. According to BBR's own figures

Supercharge 190@5260 torque and 235@7130 power
Turbocharge 226@4350 torque and 262@7350 power

The exact opposite of what I would have imagined the turbo is pulling lower down and extends its power higher in the rev range.

Looks like a no brainer - if there is no lag as pistonheads say.

If only I could do it for less than £5k

Cheers!

quote:

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Originally posted by sdh2903
Ask the good lady, does she want a linear constant power or does she crave a kick in the back when she wants to get a move on?

I've always preferred a turbo over a supercharger in my tintops purely due to the fact the turbo surge has always brought a smile to my face, however a ride in a turbo'd kit scared the crap out of me and a supercharger would have been better. I suppose an mx5 being a lightweight-ish car it's a bit of a dilemma.

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You really can't compare apples and oranges here though - suggesting a s/c is better than a turbo is like comparing 747 to a military transporter - they both have their uses, they both work well and within each category you have enough range of options to provide cross-overs that will not make sense when compared to the other.

In general - superchargers are slightly less efficient than turbos (meaning hotter charge is created and a little less power generated, but you can counter the first half of that with cooling) but if you do a lot of driving about town and/or you're not pushing high boost, the differences are pretty damn small and the s/c can make more sense.

From my reading it seems there are two types of supercharger - Eaton Screw Type (Mini Cooper S M45, Merc Kopmpressor M45/62) and Vortech/Rotrex centrifugal.

The Screw type act like you would expect a surpercharger to - good low/mod performance but runs out of puff at high rpm.

The centrifugal type are like a belt driven turbo so are better at mid/high rpm, these have been used well on the Honda K engines, I think Ariel Atom use these in the 300 model.

Also worth looking into using a electrically actuated clutch on the pulley, some Merc Kompressor models have one of these to dissengage it at high revs but it can also be used to fully disconnect and so go back to a stock engine for doing the shopping (probably need a dualmap ecu for this though). Worth a thought.

Hope this helps.

My DB7 has an old fashioned rootes type charger (eaton), it will lug the car in 5th from 1000rpm impressively for a heavy 3,200cc car.

My little car, and other turbo cars I have driven (mostly diesel) do not perform anywhere near as well as this below 2000rpm, once the revs are built up then turbo's feel even faster as the torque kicks in.

If the price is the same and she only revs up to say 4000rpm and likes to be lazy on the gears then supercharger gets my vote.

High end cars such as Mercedes tend to have superchargers on petrol variants.

This probably does not apply to small volume aftermarket kits but my recent experience is a modern turbo is far better than a supercharger.

Back in the 80's and 90's I tried several petrol cars fitted with turbo's including Cosworths and found them all to be exciting to drive but once the turbo came in you needed to concentrate. I never actually bought one as I felt that they did not suit my needs or pocket. We eventually bought our first turbo diesel back in 1996 which was a Golf TDI, so much better than anything else on the market at the time.

Come 2005 I bought a Mini Cooper S which at the time was fitted with a supercharger. The power was very linear with no sudden rush of power but below 4000 rpm it did feel slightly dead, not what I really expected. It never felt fast despite its claimed 172 PS.

Since 1996 we have always had a turbo diesel on the drive. Every one has been better that the last one, the best was fitted to a BMW 118D, quite superb. The wifes current car is a Kia Ceed 1.6 CRDi, not quite as good as the BMW but way better than any other turbo diesel we have owned. Pulls from 1500 rpm with no sudden rush of power and its still pulling at the 4500 rpm red line.

Last year I bought a new Seat Leon 1.4 TSI. Its got the 140 PS engine in it, not the nasty twin charged unit that had a bad habit if disassembling itself as you drove but the brand new engine introduced in the Mk7 Golf. Max power is 140 PS between 4500 and 6000 rpm, max torque is 184 lbs/ft between 1500 and 3600 rpm. The car feels fast because the turbo pulls from little more than tickover with no lag whatsoever. Normal overtaking requires only a slight increase in pedal pressure, drop a gear and floor it and it goes like a rocket.

But VAG will have sunk countless millions into developing this engine, I doubt any aftermarket conversion would come close.

You need to try a few cars from different companies. I once drove an XR3i from Turbo Technics. It had a claimed 170 bhp and it felt like it but every time you pressed the loud pedal it tried to launch you off the road.

Power is worthless if you can only use it in truly exceptional circumstances. Its a total waste of money making a great car like the MX5 worse than standard.

Up to about 180 bhp it depends on what price you can get the kit for for, there is little difference - superchargers are a bit more 'linear' as in they don't knock you back in the seat really - If she wants over 200bhp then turbo all the way