Supercharger Pulley Change?

[mrburdon123]

A mate of mine said he was getting a larger supercharger pulley for his Mini Cooper S - something like a 15‰ diameter increase.

Does anyone know if this would possible for a VRS?

If it's possible a remap would be required too I assume?

[Ootohere]

I would go and study the Supercharger & how it functions on the 1.4 TSI  Twincharger.

Totally different from the Supercharger on the Cooper S.

 

It is operating on its own to 2,400 rpm. then in conjunction with the Turbo from 2,400 - 3500 rpm, then Turbo only.

What is it that you want to achieve that the usual Stage 1 or Stage 2 remap & Hard wear changes will not give you?

http://www.goapr.co.uk/products/ecu_upgrade_14tsi_twin.html

 

george

[vRSy]

APR looked into this and deemed it not worth the effort. As george has pointed out the supercharger is not engaged post 3500rpm.  In fact when logging the supercharger parameters via VCDS its evident that the supercharger disengages below that more often than not.  My car was fully disengaging by 2500rpm when running stage 2 Jabbasport software.  Basically as soon as the ECU is happy the turbo is on boost the supercharger will disengage. The other issue we foresaw was that too much power low down would just make traction a nightmare.

 

The reason it works on the Mini Cooper S is that the supercharger operates for the full duration of the rev range therefore potential gains at the higher end of the rev range are very notable.

[Ootohere]

This is for the Twincharger pre the 2009 CAVE 132kW, then the CTHE from 2012, but it gives much of the info covering the 1.4 TSI Twinchargers.

 

http://www.volkspage.net/technik/ssp/ssp/SSP_359.pdf

[leevrs180]

You could replace superchager but seen done on a car on a forgein tuning website but it was near on impossible to find info

[Sparkly]

I can appreciate the OP's question, as I am naturally a curious sort myself.

 

Given how much torque the car produces stock though and how early that comes in I think Sy's comment on drivability if you were to boost this significantly is probably a bit more relevant than whether it is technically feasible.  Given that we live in the land of Citigo's being tuned to produce 400bhp it's probably safe to assume that there is scope to do something with the charger.  The question really is whether you would make the car better or worse.

 

As a small aside It also seems to be that the few people who have gone Stage 3 Hybrid (albeit turbo) on this engine in the UK aren't recommending it much to people.  Sy has commented a couple of times on here that Stage 2 is more than fast enough and there are some big issues to overcome going hybrid.

[Yeti_Man]

A mate of mine said he was getting a larger supercharger pulley for his Mini Cooper S - something like a 15‰ diameter increase.

Does anyone know if this would possible for a VRS?

why would he want to decrease the boost that the supercharger produces?! Personally I'd leave the standard supercharger setup well alone on the VRS.

[philhoward]

A pulley change is to change the speed of the supercharger - in the case of the Mini, is uses up the spare capacity and in extreme cases takes the poor old Eaton out of its efficiency zone (increased heating and load for not a lot more output; the law of dimishing returns).  This is, I believe the original JCW mod?

 

The VAG (M24?) unit already has a 1:2 gearbox fitted so at the current max speed controlled by the ECU (3400rpm or so), it's already working flat out.  You could possibly get it to cut out earlier if geared higher, but it would rely on the turbo ALWAYS being up to speed by that RPM otherwise you'd have a hole in the torque curve at the switchover point in some circumstances.

[mrburdon123]

Appologies, I ment a 15‰ decrease in diameter.

Surely if the SC builds boost quicker, when the map sensor reads the required pressure, the DV valve will just direct the excess pressure back to the intake, the turbo then kicks in at its specified rpm and all is normal again?

And as this is a mechanical change, remaps running higher boost levels would benefit from the extra pressure the SC can generate for a given rpm as the SC rpm is a direct ratio to the crankshaft speed?

So the only benefit this would give to a std vrs would be faster boosting time at the bottom end?

Forgive me if I have no idea what I'm on about.

[vRSy]

Higher inlet air temps as aresult of higher boost will become a massive factor even with an IC, which considering how badly it suffers with heat soak when stock and stage 1 means IMO it will only compound the issue.  

 

Then theres the tractability, too much boost/torque low down will just light the tyres up.  Power is useless without control.

 

Then theres the potential of developing a flat spot on the changeeover.  If the supercharger is pushing the boost that high, when the turbo takes over as the sole source of boost there could be a distinct drop in boost levels resulting in a flat spot in the power delivery.

 

Then theres the limit on boost with the stock turbo.  The max safe limit is 1.6Bar.  Stage 1 maps run aprox 1.4 bar at approx 2.5krpm (Stock is 1 bar).  Stage 2 cars run aprox 1.5-1.6 Bar at 2500rpm.  The extra boost would just mean the turbo runs at its maximum duty cycle which means the turbo will most likely die early and any extra power it could have made will be lost through heat.

 

So yes you would make more boost, but whether that boost would equate to extra performance is highly debatable.

[Sparkly]

[Sparkly]

Hehe memes.........

[mrburdon123]

The torque would still be less than a diesel.....the boost pressure would remain as requested by the ecu so venting the boost would happen earlier in the rev range so when the turbo kicks in, the boost would be as it normally would be?

[philhoward]

Only if the turbo has fully spooled up, that is..

[Ootohere]

mrburdon123,

have your read all this yet, particularly page 16. ?

http://www.volkspage.net/technik/ssp/ssp/SSP_359.pdf

 

What else were you thinking on doing with the Engine and gearbox, & is the car for road use or some motorsport or track use?

 

Re Torque & the Petrol Twincharger,

the standard figures for the 180ps car is 250 Nm 2000-4500 rpm, Max ps 180 @ 6,200 rpm

The 1.6 TDI 105 ps is 250 Nm 1500-2500 rpm , Max ps 105 @ 4,400 rpm

 

george

[mrburdon123]

Have read u to page 16........why can't it be done then?

Will be doing nothing to drastic the the engine, changing the pulley seemed like possible simple change.

[Sparkly]

Do it, Dyno it, Don't break it!!!!

 

 

.........then report back

[philhoward]

Page 15:

Turbocharger and supercharger operation at high 

loads and revs between 2,400 and 3,500 rpm

In this range, the boost pressure is produced at, for 

example, constant speed, by the turbocharger alone. 

If the car now accelerates quickly, the turbocharger 

would be too slow to generate the boost pressure fast 

enough. There would be turbo lag. To avoid this, the 

engine control unit activates the supercharger briefly 

and adjusts the regulating flap control unit according 

to the required boost pressure. It helps the 

turbocharger produce the necessary boost pressure.

 

If your supercharger has run out of speed (15% decrease in pulley diameter means it will have to cut out around 3000rpm or so), the turbo might not be able to match the boost pressure, so sudden acceleration will give you a point of lag until the turbo wakes up.

 

As Sparkly says - if you want it, try it....and see if you can find a tuner to remap the ECU to do it otherwise you'll burn out the SC and turbo in very short order I'd have thought..

[mrburdon123]

It was just a passing thought, I won't be trying it but thanks for your comments.

[Ootohere]

Anything can be done, the pulley can be made, the suitable belt can be found.

 

The question i am asking is why you are going down this particular route,  what you want from the engine?

 

Tuning and increasing performance is easily done.

Reliability is harder to achieve, and given the past experiences of some with Twinchargers that have put some money into their projects,

i personally do not think modifying the Supercharger is the way to go.

 

But someone doing something is a good way of us finding out, without having to do it ourselves.

Lets us know how it goes.

 

EDIT, sorry, i was typing as you posted saying you would not be doing it..

[mrburdon123]

I just thought that as there is no changes to the SC other than the fact SC rpm is higher across the rev range (due to a smaller pulley) the requested boost pressure will be achieved earlier, meaning the turbo will be utilized from lower rpms. I make this assumption guessing that the ecu controls the positioning the regulating flap based on pressures and not SC rpm.

Referencing the document linked in sk4gw's post and page 13, basically, reducing the rpm value of the green to blue transitions.

[Ootohere]

The thing is the 0-30 on a standard vRS is not great, but 0-80 0-100 or 0-120 as examples is pretty good.

Rolling starts and acceleration as standard, (or Stage 1, in excess of 200 bhp) is very good from a standard minimum 178 BHP.

Tractability and acceleration through the various rev ranges and gears is pretty good, and stage 1 or 2 can improve that without too much risk to the engine or drivetrain.

 

Getting the power down/traction is really the reason for the 0-30 not being great.

Tyre compound and size can assist on the traction from standing starts.

That is why i was asking what you want to achieve with the mod.

 

http://www.briskoda.net/forums/topic/209657-14tsi--14-mile-leader-board

 

george

[vRSy]

Stage 1 cars with 200-210Hp hit consistent 5.5 second 0-60s a the strip when using genuine track timing equipment.  Add a further 50-60Hp and that 0-60 time doesnt reduce that much at all, thats due to traction.  i actually reckon 0-60 would increase with a supercharger upgrade as traction would be harder to achieve.

 

 

I just thought that as there is no changes to the SC other than the fact SC rpm is higher across the rev range (due to a smaller pulley) the requested boost pressure will be achieved earlier, meaning the turbo will be utilized from lower rpms. I make this assumption guessing that the ecu controls the positioning the regulating flap based on pressures and not SC rpm.

 

 

To highlight why i dont think this is required:

 

Peak boost is achieved at only 2000rpm with a Jabba stage 2 custom map.  You can see there is no issue with the car making high boost very very early in the rev range.  As said before the max safe limit for the turbo is 1.6 Bar.  But you also have to take into account the EGTs/IATs on the car.  This map is peaking at about 1.48Bar so is a realistic and safe setup for a mapped car.  Having had a car mapped by  " A N Other" tuner on here which requested much more boost than that on the stock turbo I can honestly say it suffered alot more heatsoak as a result. It also smoked like a good un.  

 

 

As i said in an earlier post.  This is why the Supercharger more often than not disengages much earlier than the 3500rpm stated in the VW Tech Doc.  My experience of logging my car shows that the supercharger disengages whenever it detects the turbo is on boost.  This occured typically around 2500rpm on the Jabba software.

 

I just cant see how a supercharger pulley upgrade would work on this car. Evfen with my car running the stage 3 Hybrid turbo APR didnt see the point of running any supercharger changes.  They would only be required if yoyu were running a much arger turbo like a GT30 or similar to allow the supercharger to cover the boost of the larger turbo in the low range of the rev band.

[MattGreen]

Would changing the pulley ratio also cause more drain to the engine power at low rpm? I'm wondering whether it would make the engine a bit less revvy/willing on pick up.

If you were going to experiment I'd bet 20p that going the other way with the pulley may also be worth trying. Seeing as the SC is disengaging "early" putting less load on the motor and pulling boost later on may make for a faster accelerating car. It may not but it's worth a 20p bet. Chances are VW have got it about right IMO.

[sharkrider]

arn't we missing a fundemental? I thought the supercharger on the vRS engine was  gear drive...... no belts involved