ESS Supercharger

[exdos]

I know I'll get slated for this, but what's the effect on MPG if you add the supercharger - assuming you drive as you do now and only use the extra power 'when needed'?

I'm not asking due to the cost side - although if you're going down from 30mpg to 10mpg it may be an issue - but rather how far can I travel on a tank, as for a daily driver I don't want to have to stop to fill up before I leave, half way, and when I arrive at my destination.

If there is an impact on MPG, then I assume this will increase as you up the power levels.

Personally, I'm aiming for a 25-30% increase as a first step, and then increase it by another 25-30% once I get bored.

I think that's a very legitimate question, especially for you for the mileage that you do.

Fuel consumption is proportionate to the airflow through the engine. Under power, the AFR (Air:Fuel ratio) is around stoichiometric levels (14.7:1) and at WOT, the AFR gets richer (i.e. more fuel used), therefore if the supercharger increases airflow by, say, 50% then you'll use 50% more fuel. Having said that, if you look at the graph below, which I've just produced for you from datalogging my car, you'll see that a fair amount of time, when you're off the throttle, the fuelling is such that the AFR is at 29.2:1 (shaded green section) and it's when you're doing WOT accelerations when the AFR goes below stoichiometric values as shown by the red shaded section.

In the same way that it would be great to have electronically adjustable dampers from the driving seat, it would be great if there was an adjustable geared supercharger which you could simply turn the boost off when travelling on longer journeys from a control module inside the car. You'll have to perfect your eco-mode style of driving on motorways.

 

[mmm-five]

That lines up with my guesstimations, and one of the reasons for only going up 25% in power for the first stage.

In theory, my 27.5mpg average would go down to about 21mpg - or a loss of about 80 miles of range (330 down to 250).

Although in my limited testing, a ±5mph change in velocity around the 80mph cruise equates to a respective ±1.5mpg.

Maybe I can find someone who can do a clutch for it, like on the air-con compressor, so it's only on when I press the sport button

 

[peddy]

Maybe a silly question, but could you not mod the sports button to control power level and therefore better MPG when it's switched off?

 

[pilchardthecat]

Presumably the supercharger requires the fitment of different (larger) injectors etc? I doubt the existing fuel supply system could keep up with a 50% increase in airflow

 

[exdos]

Maybe a silly question, but could you not mod the sports button to control power level and therefore better MPG when it's switched off?

Since the SC is permanently operating, it is permanently supplying a greater supply of air than otherwise occurs when the car is normally aspirating, therefore, it will permanently use more fuel than when NA. Unless the SC could be clutch operated to switch it on/off, I can't see what the Sports button (or any other button) could do to reduce the air supply delivered by the SC. If you add less than stoichiometric levels of fuel (i.e. run lean) when the car is under power, then "knocking" and engine damage will occur.

You could incorporate a valve into the system which would bleed compressed air from the system (to reduce pressure) before the air enters the engine to reduce fuelling, but a SC takes about 70HP to operate so whether there would be any economic sense in doing this would depend on calculations.

 

[Beedub]

i get around 16mpg........ injectors are used from the v10 m5. y biggest bug bare is the fuel consumption, its really bad.... during track sessions i can run through a full tank very quickly so have to limit my runs to make it last till 4, leaving just enough for the journey home usually.... it seems OK on the motorway as it tends to only show around 1 lb or boost in this situation....

 

[exdos]

i get around 16mpg........

Ouch! 50% more air = 50% more fuel consumption.

 

[mmm-five]

Maybe beedub should lend me his for a couple of weeks so that I can use it on my commute - purely in the name of research so I can see what the real world figure is on my 200 mile commute

 

[alfamale]

Dont kill me but why does everyone think of bigger brakes when increasing power? brakes depend on weight they are trying to stop and speed, assuming you have not increased the weight and most likely you wont be going any faster the brakes should be fine, you are likely to be going faster between point to point so you will use them more often or harder, this effects brake cooling so should you not look to upgrade cooling and heat dispersion?
admittedly bigger brakes have better heat dispersion or generate less heat for similar braking forces but maybe just upgrading pads and getting better fluid could be enough or ducting better airflow to the discs.

 

[mmm-five]

Dont kill me but why does everyone think of bigger brakes when increasing power? brakes depend on weight they are trying to stop and speed, assuming you have not increased the weight and most likely you wont be going any faster the brakes should be fine, you are likely to be going faster between point to point so you will use them more often or harder, this effects brake cooling so should you not look to upgrade cooling and heat dispersion?
admittedly bigger brakes have better heat dispersion or generate less heat for similar braking forces but maybe just upgrading pads and getting better fluid could be enough or ducting better airflow to the discs.

Sounds like you've just argued for & against bigger brakes all at the same time

I'm only going for upgraded calipers on the front and using OEM discs. I'm mainly doing it for increased duty cycles and pedal feel rather than outright stopping power.

 

[Beedub]

Dont kill me but why does everyone think of bigger brakes when increasing power? brakes depend on weight they are trying to stop and speed, assuming you have not increased the weight and most likely you wont be going any faster the brakes should be fine, you are likely to be going faster between point to point so you will use them more often or harder, this effects brake cooling so should you not look to upgrade cooling and heat dispersion?
admittedly bigger brakes have better heat dispersion or generate less heat for similar braking forces but maybe just upgrading pads and getting better fluid could be enough or ducting better airflow to the discs.

hi their Alfa, good to see a post from you, youve been quiet of recent...
interesting point... ive always though the stock brakes were awesome imo, very good, i added stage 1 and kept the stock brakes... And they definitely 110% was pushed to their limit and actually experience proper brake fade on only 2 lap sprint sessions ( sprint circuits tend to be hard on brakes) , i then went to stage 2 and they literally wilted... the rotors overheated and i boiled brake fluid, since going to the AP setup ive never experienced a problem, they smoke alot but actually get better as each lap passes... however the trade off??? they are s**t when cold, they stink, they cover the car in dust and the noise is near embarrassing, and to replace parts seem overly expensive, the pads are like 350 quid??? WTF....

 

[Beedub]

Maybe a silly question, but could you not mod the sports button to control power level and therefore better MPG when it's switched off?

Since the SC is permanently operating, it is permanently supplying a greater supply of air than otherwise occurs when the car is normally aspirating, therefore, it will permanently use more fuel than when NA. Unless the SC could be clutch operated to switch it on/off, I can't see what the Sports button (or any other button) could do to reduce the air supply delivered by the SC. If you add less than stoichiometric levels of fuel (i.e. run lean) when the car is under power, then "knocking" and engine damage will occur.

You could incorporate a valve into the system which would bleed compressed air from the system (to reduce pressure) before the air enters the engine to reduce fuelling, but a SC takes about 70HP to operate so whether there would be any economic sense in doing this would depend on calculations.

these operate rich......

i run 11.5 AFR at redline....

 

[exdos]

these operate rich......

i run 11.5 AFR at redline....

The OEM runs at richest at around 12.7 AFR. Why do you have to run so rich: is it to ensure engine cooling with warmer air from the SC?

 

[Beedub]

these operate rich......

i run 11.5 AFR at redline....

The OEM runs at richest at around 12.7 AFR. Why do you have to run so rich: is it to ensure engine cooling with warmer air from the SC?

I'm not to sure really ??? But a little research shows most FI cars run 11.5-12 AFR at wot. AITs are however very low.... The supercharger itself does get very hot however... Hot enough you can't touch it.


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[exdos]

I'm not to sure really ??? But a little research shows most FI cars run 11.5-12 AFR at wot. AITs are however very low.... The supercharger itself does get very hot however... Hot enough you can't touch it.

I've done a bit of searching and have yet to find the answer. Since you don't run a MAF I presume that your ECU fuels "mathematically" based on predicted airflow (i.e RPM X boost pressure) and to ensure that you don't run lean, it adds a bit more fuel. Does that sound right?

 

[Beedub]

I'm not to sure really ??? But a little research shows most FI cars run 11.5-12 AFR at wot. AITs are however very low.... The supercharger itself does get very hot however... Hot enough you can't touch it.

I've done a bit of searching and have yet to find the answer. Since you don't run a MAF I presume that your ECU fuels "mathematically" based on predicted airflow (i.e RPM X boost pressure) and to ensure that you don't run lean, it adds a bit more fuel. Does that sound right?

Basically correct...... In terms of the actually AFR figure , if we run towards the 12 mark the car makes quite abit more power .... Sticking fi on this car has really led to some interesting conversations and research ...... I still think for the best balance the car was most fun and drive able on the stage 1.... Sometimes I wish I would have stayed at that level just for the sheer plug and play aspect.


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[exdos]

From my reading on this subject, it sounds as though your kit has been very reliable compared to the experience of some. I was at a track day at Donington about 4 years ago and there was a E46 M3 with a SC (by CA?) which spent most of the day having a SC belt refitted time and again. It looked like something off a 450W sewing machine rather than a proper industrial quality belt for making 450HP.

 

[Stuart Truman]

In the same way that it would be great to have electronically adjustable dampers from the driving seat, it would be great if there was an adjustable geared supercharger which you could simply turn the boost off when travelling on longer journeys from a control module inside the car. You'll have to perfect your eco-mode style of driving on motorways.

Solenoid operated dog clutch, a la James Bond's old Bentley from the books. Link it to the Sport button...

 

[Beedub]

From my reading on this subject, it sounds as though your kit has been very reliable compared to the experience of some. I was at a track day at Donington about 4 years ago and there was a E46 M3 with a SC (by CA?) which spent most of the day having a SC belt refitted time and again. It looked like something off a 450W sewing machine rather than a proper industrial quality belt for making 450HP.

Never lost a belt from day one..... Infact the kit has been faultless.... Definitely no regrets ...


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[Bigpow]

You can get good drive train Polly belts from fenner and the like. Does the ecu not take any information from the lambda sensors with regards to fueling ?... I didn't realise the engine was running without a maf..
On par with an old roots blower and twin 40's

Sounds like an awesome investment though but what are we talking about including m5 injectors and fitting 8k ?
Brakes and engine mounts 2k

So 20k ish for a car that eats many others before adding a blower is a bit of a bargain as long as you can keep it on the road