I know it has been done, but can anybody tell me the real implications of what needs to be done to get it to work?

Or, 20V into 20VT - would you have to swap driveshafts and gearbox to do this?

What about any cylinder head work etc?

(im weighing up options for my beloved porto)

na would need compression dropping

new camshafts also

does anyone have the cam timing figures ?
all this talk of cams has got me curious and wanting to see exactly what they are

+




For turbo conversion, or supercharging, or both?

compression is typically lower for forced induction than normally aspirated applications

this of course depends on boost levels

i wouldnt automatically say cams need changing as many sc conversions use mild cams fitted as standard to na cars

however the cam part is speculation without knowing more about the two types of cam and also the variable valve timing carried out by the engine management

Both, more so with a supercharger.
Same for Cr, a supercharger would tend to be lower than a turbo might survive at.

Interesting.

So does the 20v have significantly more compression than a 20VT?

What sort of levels are we talking?

60psi...ish more then the 20vt but don't quote me on it as it's late

Have you seen the thread on that Marea estate, unsure whether it ever got finished but it looked interesting, chap used a mini SC I believe.

you need a static compression ratio for it to be meaningful at the engine building stage so you can work out what needs to be increased and essentially by how much

this is typically achieved by a changr of pistons ( flat to dished or bigger dish, shortened deck height pistins), decompression plate ( a metal head gasket sandwiched between two head gaskets), or cylinder head combustion chamber reshaping.

to calculate the (static) compression ratio...

you typically need the following information
bore size, stroke, head chamber, head gasket volume, ring land volume and deck volume

do a quick google there are many online calculators

it simply isnt practically possible to calculate effective or dynamic compression. the cam duration and opening and closing rates will change the other 'theoretical' compression ratios.

As Rudi said, it depends on cam spec. But I'd say very unlikely you'd have to change them. Standard factory cams tend to be extremely mild with little duration and overlap - great for turbo or superchager conversions.

Lowing static compresion is a good idea, but whether you would need to depends very much on how much boost you want to run, octane fuel and what type of supercharger you will use.

positive displacement SC's (Roots type) are pretty inefficient around 50%. Meaning they put a lot of heat into the system for whatever asmount of boost they make.

Centrifugal 'chargers, such as the Rotrex charger are a lot more efficient. they can be up to 80% efficient. So that means they put produce less heat and hence less stress on components compared to a Roots-type 'charger. And hence lower requirement for higher octane fuel / lower compression ratio for a given amount of boost compared to a Roots.

A friend of mine used to own a Golf VR6, which he later supercharged (Vortech, IIRC). It went from standard 167bhp to 280bhp at just 12 psi. And surprisingly it didn't even run an intercooler!

Centrifugal 'charger conversions are popular with other makes of car. Nobody really does it on Coupes because TBH, it's much cheaper and easier just to buy a 16/20 VT.

Doesn't mean you shouldn't do it though. It's nice to see something different

Personally if I was going to build a 20V supercharger conversion I'd lower the compression to maybe 9:1, use a Vortech or Rotrex 'charger @ 10-12 psi, along with an intercooler.

interesting KJ

from what ive read superchargers return an increase of 35-40% power. they do suffer from thermal inefficiencies. the Eaton 45, as fitted to early bmw minis, maxes out at 14,000 revs.

they key is not running them to the point where there is a diminishing return.

The Eaton M45 was originally fitted to the BMW Cooper S Mini. The displacement of the M45 is 45 cubic inches per revolution, 0.737 litres, its sustained rpm is 14,000.

Employed on the MINI the E45 turns at a ratio of 2.06:1 against the engine revolution and produces 12psi maximum boost.

The drive pulley on the supercharger is 65.9mm effective diameter.

If you were to run similar boost pressure with greater engine capacity (the MINI was 1600cc) you should work on the assumption that the E45 needs to turn faster by a ratio of the increase in capacity.

I have a supercharger calculator but my manual calcs dont seem to match. So if anyone has any comments please feel free....

Supercharger pulley ratio for Coupe

= Coupe cc divided by BMW Mini cc multiplied by BMW Mini Supercharger ratio


= (1800/1598) x 2.06

= 2.32

So, the supercharger pulley ratio for Coupe mini is 2.323. The circumference of the drive pulley will be 2.32 times that of the supercharger pulley.

Supercharger pulley circumference for Coupe

= Supercharger pulley circumference x Pi

= 65.9mm x 3.1416

= 207mm

So supercharger pulley circumference = 207mm

Crank pulley calculations (based on running similar boost (12psi))

Crank pulley circumference

= supercharger pulley circumference x supercharger to crank pulley ratio

= 207mm X 2.32

= 480.2mm



Effective diameter of crank pulley

= crank pulley circumference / Pi

= 480.2mm / 3.1416

= 152.85


Adjustments to the calculations will need to be made to account for different boost levels. Also worth noting the hp scavenge effect at various revs.

The above are just raw calculations based on pulley sizes and crude air volume calcs.

In terms of cam choice, i agree that mild cams are most suited.

should have said 1800 = 16v, got carried away

for 20v substitute figures

Another cute way to avoid having to lower the compression ratio would be to adopt the Miller cycle

http://en.wikipedia.org/wiki/Miller_cycle

This would require a longer duration inlet cam so that the inlet valve is not closed until around 61-75 degrees after bottom dead centre. It might be worth speaking to Kent or Piper cams to see if they could re-profile the standard cam for a suitable duration and maybe add a bit more lift at the same time.

Like others on here, I have no idea of the standard cam timing for the NA 20V and have had no luck Googling for an answer.

Seems like its all possible, i quite like the idea of supercharging i must confess, i know it s easier to buy a 20VT... i already did

But, i'm all for one offs and being different, so we'll see i guess, not going to be an overnight project by any means, still got stuff to do on the 20VT before Spa.

someone donate me an old shagged engine and i'd collect engine specs all day long.

does anyone know what checking height is used for fiat or coupe cam figures?

I've found the Bravo 20V cam details - I don't know if they are exaclty the same or completely different!

Timing is -9/49 / 27/7 with inlet lift 9mm and exhaust lift 8mm.

(yes, the inlet valve opens 9 degrees after top dead centre)

With old fiats (pre hydraulic cam followers) it used to be 0.8mm I believe. I think it likely the Bravo ones above are measured from the point lift begins to when it ends - i.e. including opening and closing ramps. Could be wrong though!

are you going for a mild setup?ie 200bhp or so?easiest way to me would be to buy a 20vt engine,ditch the turbo and fit na manifold.get an m45 as said earlier from a mini (go for the later version as its more reliable)then you will need to have some pulleys made to run within the 14000rpm limit of the charger(if your engine runs 7000rpm the pulleys would be 2:1 ratio),obviously you will need to fabricate the mount and sort where the pulleys are going to go (bear in mind the extra pulleys will put additional load on the crank or what ever you attach to)then you will need to have it mapped.you will need new pipe work to fit your maf in line with the charger and from the charger to the inlet manifold.an m45 will give 220bhp max from what ive read.boost pressure is more a by product of the flow of the charger vs the engine restriction,so look at what flow the charger will put out at certain revs.hope that helps a little.

Again, without knowing the checking height we cannot make any direct like for like comparisons as the duration will vary with different checking heights.

but just for fun / discussion ive punched the values into my cam xls calculator...

Intake duration 220 degrees
Exhaust Duration 214 degrees
Lobe centre angle Intake 119
LCA Exhaust 100
Lobe separation Angle 109.5
Overlap -2

would imo suggest a mild cam with good emissions characteristics.

does this mean high lift to compensate relatively short duration? or efficient breathing? or large checking height measuring cam movement later in the 'cycle'?

what we dont see - and is the secret golden egg of tuners - is the amount of lift on overlap.

I would imagine, with a supercharger + map, plus a few supporting mods, it would be around the 250BHP mark.

From what i saw of the supercharged Marea, the aircon pulley system can be re-engineered to take the supercharger itself + a few more brackets etc, probably more difficult to set up all the various new pipework, and or source a decent supercharger.

As posted, the Mini M45 seems to be a sensible choice, however i think its possible to broaden the horizons a bit, maybe go for something American, maybe even from a V8 or something similiar.

Another option i'm toying with is an Alfa V6 transplant...

look at the merc superchargers,they are eaton as well but are slightly larger,they will be a better choice for thois application if going for that power. from the slk or clk kompressor range,m62 iirc

The Eaton M045 only has a flow of 0.65 litres per revolution. It has a maximum speed of 14000 rpm. Therefore with a 2.14:1 pulley ratio it will output 1.391 litres per engine revolution.

At 1 atmosphere the 1998cc the engine requires 0.999 litres per revolution, so the M45 can only provide 1.4 times the air that the engine requires. Max boost it could produce on the 1998cc engine is therefore (1.4-1) x 14.7 = 5.88 lbs.

It's just not big enough to be worthwhile. An M062, however, outputs 1 litre per revolution which means that it could comfortably provide 1.1 bar (16.2 lbs) of boost upto 7000 rpm, if the engine could be made to breath effectively at such a speed, with a drive ratio of 1.95:1. It is a much better match for a 2 litre engine than the Mini supercharger which will only flow about 200BHP.

Theory is the M062 is good enough for 290BHP with good intercooling.

If you want a Sprintex S3-210 (0.94 litres per revolution output) which is good enough for 270BHP at 6500rpm on this engine (16.2 lbs boost, drive ratio of 2.08:1) send me a PM.

My calcs suggest 0.125mm inlet lift at TDC and 1.25mm exhaust lift at TDC........

In terms of overlap degrees, at 0.5 mm lift (both valves) only about 6 degrees - all before TDC obviously.....

As per normal, all of your technical knowledge stuns me.

Kudos to you sirs.

I'm not going to rush this one, i could just fix the head gasket on the 20v, and be done, but after ALOT of thinking about which of my other coupes to sell (16v or 20v) i just cannot bear to be parted with my porto.

It always was, and still is a fantastic example, my broom 20v i had for a few months last year was no where near as good, just never felt as strong, or as solid as the porto.

Now having bought a near perfect 20VT (which is not going anywhere!) i want to sell the 16v, and use the porto as a bit of a project car, it has NO rust, the underneath is in fantastic condition, the only real place where you can see any rust at all is typically in the engine bay, which if i'm honest i have never really cleaned/tidied since i bought it - untill now anyway.

I think once i've researched, and decided which/what engine i'm going to put in it, i'll have the engine bay taken back to bare metal, then painted, and probably when its all done, get the whole car painted, not because its faded, or laquer peeling etc, but mainly due to a lot of tesco dings in the doors, and an annoying dent in the o/s rear quarter.

Probably going to put a set of leathers in it too, although it has to be said the cloth thats in there looks like its brand new.

I dont HAVE to have big power in the new trim, as i was always happy with the N/A performance, its more involved to drive than a VT, and in a sense more rewarding, but alas, on occasion you do wish you had a bit more oomph to see off those pesky TDI Golfs!

We'll see i guess, long live the coupe

I would not opt for the eaton type blowers as they would have a higher parasitic load, as you would probably mount in place of the AC compressor this load would be through the AUX belts a week point on these.
On the turbo the AC clutch disengages when you boot it.

I think a supercharged 20v would make a nice interesting car, if it were me I would use a Rotrex charger and do something with the gearbox ratio's either a close ratio set or a higher final drive.

I'd do it if I had the time, think of the noise it would make!!

Well for starters I'd start with the four cylinder unit (sorry if this upsets anyone) but it would make a better base for a power unit. Then why not supercharge and turbo. ? It has been done once before that I know of.

got a volumex supercharger if anyones interested

Shiny
This is my thread from 2008 when i had a NA and had the same idea - I was toying with the ideia of using a Eaton M45 Mini CouperS Supercharger...

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=707260

... may be of some help

thanks mario

So here is another question - given that the 20v has too much compression as standard to run the 20VT turbo, what about running lower boost?

Maybe in the 180bhp - 200bhp zone, i'm guessing maybe 0.5 - 0.7 bar?

Not more than 0.5 definitely.

I did a couple of Mercedes charger conversion, and after 0.5 bar it was a major temp increase.

True.

But, with a 20VT rad, and an oil cooler conversion, might be back in the sensible range.

Or, what i've always considered doing since i got my 360 bumper, some sort of fibre glass ducting from the vents to the important stuff, to keep temps down a bit.

radiator and oil cooler will not reduce charge air temps,you need an intercooler for that.

Reckon the old FMIC will be needed......

So nobody liked my supercharged and turbo'd idea then ?

Aye. forgot to put + intercooler.

Although the more i consider 'tuning' the 20v engine, its seems more hassle than its worth.

Still pondering my options, but i think possibly something as drastic as a RWD/4WD tubular chassis type thing.

V6/V8 maybe.

For example - written off TVR Griffith/Cerbera V8, priced between 3 and 8k, aslong as chassis is still straight, everything else can go in the bin bar the chassis, engine and box, brakes, electricals etc.

With ALOT of blood, sweat and tears, you could retro fit a coupe over the top of another chassis, obviously removing floor, firewall etc and replacing.

Expensive too!

We'll see.

twincharging is badass,delta s4 styleeee

There is a fella who has built a twin charged integrale, pretty cool.

heres a twincharged engine on the dyno,badass
http://www.youtube.com/watch?v=uqg4SVFYRVI&feature=related

Ressurecting this thread with some info that may be of interest to anybody considering supercharging their 20V – or 16V for that matter.

I tune other makes of car besides Fiat Coupes but I very rarely mention them on fccuk. However, I’ll make an exception with the following because it is an example of the driving characteristics of well built, well tuned positive displacement supercharger conversion.

This particular conversion is on a 1.8 litre Renault Clio 16V. In fact the only supercharged UK mk.1 in existence.

Brief spec:
Opcon twin-screw supercharger (positive-displacement, similar to a Roots-type but more efficient)
Intercooler
Low comp pistons
Custom-made inlet manifold


This particular conversion is a draw-through setup, meaning the throttle body is placed in front of the ‘charger so the ‘charger ‘draws through’ it. The diagram illustrates the setup.



You might think that having to drive a great big supercharger, not to mention having the throttle body separated from the manifold by about 5ft of tubing and an intercooler, would hurt throttle response, in fact the complete opposite is true – the throttle response is instantaneous and the engine revs up with tremendous speed. Saying it revs like a motorbike really isn’t that much of an exaggeration.

How it drives:
This 1.8 litre engine makes 193 bhp @ 10psi – a fairly modest gain of 56 bhp from the official stock figure of 137 bhp. The way it makes that 193 bhp is the most impressive thing. Instantly accessible torque at any revs, from idle to redline – in this particular car you could drive off fast from a standstill in 5th gear. The power is also totally controllable and predictable; no lag of course, and no waiting to hit the boost threshold or come “on-cam”. I’d describe the driving experience as like having the same engine but twice the size. The engine er, kinda behaves in the same way - just, well, bigger!

Below is the dyno printout for this car. Below that is a N/A Clio I'd tuned previously; This time a 2 litre Williams, essentially standard bar fast-road cams: Comparing the two you can see that the Supercharged 1.8 consistantly makes around 30 lbs-ft more than the N/A 2.0 from 3000 rpm upwards.



Previously I suggested a centrifugal charger conversion would be best. Well, now having driven both, I’ve changed my mind A positive displacement 'charger conversion might be harder to build due to the size of the unit and the shape of some of the outlets. But for sheer torque and driveability, positive displacement can’t be beaten!

What are the valves like on the 16v? when I had my 19 16v I always remember hearing people say that the engine in early development stages was partially designed with a possibility for developing forced induction, but probably myth??

must admit the renault clio/19 16v's were not the most reliable cars although they were awesome drivers cars so long as you drove them to the redline any problems with upping the bhp? I know engine placement with the exhaust manifold close to the bulk head meant that a good condition cooling system was a must, thus mine never overheated.

I've never heard of the F7 engines being developed with FI in mind, but they do have sodium-filled exhaust valves and piston oil-spray bars.

My own 16v (1.8)Turbo made just over 200bhp @ 8 psi. One of the guys I know has a 250 bhp 2.0 and does does 12 sec. quarters. There have also been a few in the past making well over 300bhp. The engines can handle pretty big power - unfortunately the gearboxes can't! Even mildly tuned Clios start popping gearboxes like sweets when given a bit of stick.

As for reliability, well it's the reason I bought a Coupe. As standard the Coupe wasn't as fast or as good handling, but I quite enjoyed the novelty of not having to replace bits that fell off/broke/mysteriously stopped working every month!

I've had a Turbo booked in for the last month, but the poor guy's car keeps breaking down! Even last week he was on his way down to me when his gearbox gave in!

thanks for that honest answer, my 19 eventually started to have issues with 2nd gear synchro. I remember room being tight and on my friends clio 16v it was even tighter.
great handling cars and loved mine to bits despite being more tempremental than my 20vt

could consider one of these

http://cgi.ebay.co.uk/FIAT-PUNTO-COUPE-E...#ht_1505wt_1139

Anyone tried one of these? What supporting mods might it need on a 20v na?

Swin was joking! Those belong back on the bilge pumps or whatever they came from.

AA membership for when the fans restrict the air getting into the engine under moderate to high rpm and throw themselves into the cylinder head.

As was I

That advert should be reported to ebay