Mercedes A-Class Forum banner
81 - 99 of 99 Posts

·
Registered
Joined
·
350 Posts
No problem. To be honest for a second I did think you meant to say 2.4 - 2.5 as at 3.5 the turbo would be shot into orbit.
 

·
Registered
Joined
·
350 Posts
Depends on who your asking.
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #84 · (Edited)
So in summary 465bhp is the limit?
Depends upon many factors; however NOT just who you are asking.

Probably the single most important factor being, your personal risk / benefit analysis.

THIS will certainly depend upon who you ask, that is for sure.
What one person thinks in this regard can certainly vary to another.

Just think about the following:-
1) Our cars, standard, run, if not the highest boost level for a production gasoline powered vehicle, it must be close to it, at 2.1 BAR gauge, or 30.45 PSIG.
2) Even to achieve 465 HP, every Tuner i have been able to get to admit to what they do, acknowledges increasing this to at least 2.4 BAR, or 34.8 PSIG.
3) Even this increase in power, using the standard turbo, will increase the air temperature in the inlet manifold by a minimum of 35C. (or 70%)
4) To attempt to increase the power beyond 465 HP on the standard turbo, simply makes the above situation, worse.(Not to mention, over revs the turbo)

Now, only you can decide whether you want to do that to your own vehicle, no one else,
 

·
Registered
Joined
·
62 Posts
Depends upon many factors; however NOT just who you are asking.

Probably the single most important factor being, your personal risk / benefit analysis.

THIS will certainly depend upon who you ask, that is for sure.
What one person thinks in this regard can certainly vary to another.

Just think about the following:-
1) Our cars, standard, run, if not the highest boost level for a production gasoline powered vehicle, it must be close to it, at 2.1 BAR gauge, or 30.45 PSIG.
2) Even to achieve 465 HP, every Tuner i have been able to get to admit to what they do, acknowledges increasing this to at least 2.4 BAR, or 34.8 PSIG.
3) Even this increase in power, using the standard turbo, will increase the air temperature in the inlet manifold by a minimum of 35C. (or 70%)
4) To attempt to increase the power beyond 465 HP on the standard turbo, simply makes the above situation, worse.(Not to mention, over revs the turbo)

Now, only you can decide whether you want to do that to your own vehicle, no one else,

Hi what do you think of these,

Performance chips – Chip tuning by RaceChip for MB A-Class (W177) A45 S AMG (310KW) | RaceChip

Extra 69hp its saying??
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #86 ·
I think this particular German company, (of whom I have known for some years) has a flair for marketing.
I would start by requesting before/ after, on the same vehicle, dyno run sheets, as tested on a Maha dyno.
( Not marketing department redraws, the original graphs as come off the Printer connected to the Dyno.)
They are German, (as is Maha), so a more than reasonable request, I would have thought?

Given you are in the UK, if I was looking for a Tuning Box, I think I would go with a DTUK box.
a) Their 470 HP claim seems quite reasonable and essentially as safe as any of this product can ever be.
b) They appear to be a rebranded, British version of the most reputable of the German Tuning box companies, DTE, whose claims, are not surprisingly, basically identical.
c) Given they are local to you, hopefully verification of DTUK's claims is not as difficult as I suspect will be the case if you request it from Race Chip in Germany.
 

·
Registered
Joined
·
350 Posts
@Turbo Ed Earlier when you were describing our engine's cooling system, you said that thanks to the two separate radiators (one for the cylinder head alone and another for the block) we can run the cylinder head much cooler than the block and that there are all sorts of engineering implications resulting from this. Could you please explain the benefit, maybe give me the reader's digest version if that's even possible, just break it down for me; assume you're talking with someone with decent, but limited knowledge. Google didn't help.

And thanks for all the knowledge you've shared. I'm still boggled by that 10% of headroom and I'm not the only one, but I can't argue about things of which I have zero knowledge. And I guess time will tell whether all these cars running 470+ hp tunes (which is the majority) will remain reliable in the long term. I believe they will be. But if you're saying the compressor map ends at 465, then that's it, I'm taking you know what you're talking about.
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #88 · (Edited)
@Turbo Ed Earlier when you were describing our engine's cooling system, you said that thanks to the two separate radiators (one for the cylinder head alone and another for the block) we can run the cylinder head much cooler than the block and that there are all sorts of engineering implications resulting from this. Could you please explain the benefit, maybe give me the reader's digest version if that's even possible, just break it down for me; assume you're talking with someone with decent, but limited knowledge. Google didn't help.

And thanks for all the knowledge you've shared. I'm still boggled by that 10% of headroom and I'm not the only one, but I can't argue about things of which I have zero knowledge. And I guess time will tell whether all these cars running 470+ hp tunes (which is the majority) will remain reliable in the long term. I believe they will be. But if you're saying the compressor map ends at 465, then that's it, I'm taking you know what you're talking about.
Theo,

My headroom comments need to be taken with some tolerance applied, as is already starting to play out on the other thread.
nn7man's vehicle, standard, If Litchfield's Maha is to be believed (and I think it probably is. I had an interesting talk with Maha Australia the other day) started almost 15 HP OVER the factory rating.
I suspect anywhere between 465 and 500 HP is POSSIBLE; however that does not make it either safe or correct.
I shall be addressing this subject in further Posts, hopefully later this week, probably on the other thread as this seems to be where most people are discussing it.

With respect to the split cooling system, which to my knowledge, certainly in mass production vehicles, is unique.
Incidentally, I have yet to find an accurate description of this configuration On Line from ANY journalist, anywhere in the world, at least in the English language.
However they were briefed by MB's PR Dept. it obviously completely confused them.
I obtained the info from a combination of a workshop advisory in German, (which I read) and partial disassembly of my own vehicle.

The first thing you need to keep in mind is the apparent contradiction between designing a Euro 6 compliant engine and 211 HP/Litre, at the same time.

For Emissions, you want to keep the block as warm as possible within a VERY small operating temperature range, (and get it there in a very short period of time from cold start) in order to be able run the tightest possible piston to bore clearances and ring end gaps.
For Performance, amongst other parameters, you want to run the coldest possible cylinder head for maximum volumetric efficiency and maximum ignition advance possible .
(Historically, you also needed to run hot cylinder heads/ combustion chambers for Emissions; however fortunately for us performance nuts, direct injection put an end to that)

The idea of separating the cooling system into two parts to achieve the above two apparently contradictory results, is obviously far too expensive for general use.
However, I am surprised that other High Performance car companies have not taken this approach.

Forrester is already going to accuse me of writing an encyclopaedia here, so I shall stop for the moment and wait for your further questions !! :)
 

·
Super Moderator
Joined
·
4,244 Posts
I shall be addressing this subject in further Posts, hopefully later this week, probably on the other thread as this seems to be where most people are discussing it.
If it’s more technical (and it will be) please keep it in the technical thread.
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #91 · (Edited)
And thanks for all the knowledge you've shared. I'm still boggled by that 10% of headroom and I'm not the only one, but I can't argue about things of which I have zero knowledge. And I guess time will tell whether all these cars running 470+ HP tunes (which is the majority) will remain reliable in the long term. I believe they will be.
[/QUOTE]

Theo, (et al)
Let's talk about Rolling Roads. (Love that so English expression!! :)
Going to be an encyclopaedia, so buckle in!
Before I start, some short personal CV so you know the basis on which I am writing.
Hate for you to think I was just " guessing"!! :)

1) Dyno Dynamics.
In 1995 I was the Technical Manager who specified and oversaw the commissioning of, the first commercial AWD DD machine.
(They had built a smaller, non commercial "Proof of Concept" machine for a local Technical college, immediately prior to our machine)
2) Mainline
Around 2012, by then as GM, I signed off on and oversaw my replacement as Technical Manager's complete conversion of the original DD machine to Mainline.
IE We refurbished and retained the original DD bed; however, the entire control system was now Mainline.
3) DynoJet and their erstwhile US competitor, Mustang Dynos.
From the early 90's until the GFC in 2008, I spent literally months in any given year, working with workshops in the USA, using both of these machines.
4) Maha
Almost no experience at all and absolutely none on the MSR500, which in my view, is really the first performance orientated AWD dyno which the company has offered.
They definitely HAD AWD dynos before the MSR500, which I have seen, however from my observations they had not been intended by their manufacturer to be used in performance work.

So, to start.
A lot of the differences which I am about to outline are regional in origin and it is definitely when one region's approach clashes with another, that confusion occurs.
What's more, I cannot overemphasise the absolutely critical requirement to always use exactly the same dyno for all performance development work.
Not even two different workshops with the same brand/ model of machine.
It needs to be exactly the same machine, every time.

AUSTRALIA
In Dyno's generally, not just AWD, DD ruled the market from the 80's until the late 00's.
Mainline got serious as a competitor during the 00s and by around 2010 definitely had superior controls, (Hence the swap which we did)
However, the data provided to the customer had been defined by the Chief Engineer at DD , many years' before and Mainline simply had to fall in line to compete.
That DD individual was strongly of the view that there was no accurate method to extrapolate Engine Power, from numbers measured at the tyres.
So, Australia's performance dyno market developed as Tyre Power measurement market, period.
No one ever talked anything ese.
Both DD and Mainline concentrated on building Tyre Power measurement dynos of ever increasing capacity.
When they both had 2WD units more or less measuring around 2,000 HP at the tyres, they ran into the predicable traction problems and started offering Hub Dynos, to address the issue.

This situation could have remained like this for ever, except for one thing.

In 2002 and again in 2004 I personally conducted an in depth, (weeks on each occasion) investigation of the UK's AWD Dyno equipped performance Tuning industry. (We were looking for potential UK Distributors Customers for our performance product).
That is where / when I saw Maha's predecessor to the MSR500.
Now, I am not going to write in detail on a predominantly UK site, on what I saw / concluded from those two trips, (if you are interested in detail, PM me) except to state the following facts.
1) There were approx.15 AWD Maha, mostly quite old, and none fit for purpose, in the UK, servicing a market of 60M.
2) In Australia at the same time, there were over 50 AWD dynos servicing a market of 20M. (Today there are over 200, between DD and Mainline, although the population has risen to 25M )

As we were quite close commercially at the time, I reported same to the then management of Dyno Dynamics.

UNITED KINGDOM
As a result of my reports, DD saw the obvious commercial opening.
By 2006 they had their first AWD dyno in service in the UK.
Between then and 2014 when Lichfield chose the first Maha SR500 sold in the UK, I don't know how many DD (and later I believe Mainline also) Australian AWD dynos went into the UK; however I believe a relatively significant number.
In addition, DD in particular, started to make sales in Europe. Perhaps not Germany itself, but definitely places like the Czech Republic, Poland, Italy, Scandinavia, etc.
However, both the Aussies had a marketing problem, didn't they?
Both in the UK and Europe generally, the performance market were accustomed, even then, to talk Engine Power, as that was the normal data provided, (who knows with what real accuracy) by the predecessor to the MSR500.
I am absolutely mortified to have to admit, that as Litchfield quite rightly and very politely outlines on their website (in their rationale of their 2014 Maha MSR500 purchase), that the Aussies cheated and took the technically simple way out.
Remember, they did not need Engine Power for their principal volume home market.
They were selling a handful of units into the UK / Europe, and 10's into the low 100's in their home market, where nobody talked Engine Power.
So, what did they do?
As Litchfield obviously identified at the time, they simply applied a percentage loss number within the electronic controls, which required no real re-engineering of the equipment.

The problem is, this is NOT correct and the driveline loses are NOT a fixed percentage of the power as measured at the wheels.
Simple to do electronically; however technically WRONG.

Which is precisely WHY I said to you on the other thread, if you have ever seen ANY real correlation between Engine Power as measured on either of the Aussie Dynos and a MSR500, it was simply a fluke, nothing more.

Basically the Aussie Dynos are excellent Tyre Power measurement devices, not Engine Power.

Whether the Maha MSR500 is as good at providing legitimate Engine Power numbers as most Brtish.and Europeans Tuners say it is, I look forward to seeing for myself as my personal project proceeds. The fact that there is actually one in my city, certainly at least makes this practical.

USA
I think I have written more than sufficient to this point, don't you?? :)
However, if you want to hear about the biggest joke in the legitimate Tuning world, being the "Drum of Concrete" ( DynoJet), just ask and we can continue on.
 

·
Registered
Joined
·
350 Posts
Which is precisely WHY I said to you on the other thread, if you have ever seen ANY real correlation between Engine Power as measured on either of the Aussie Dynos and a MSR500, it was simply a fluke, nothing more.
I guess it was a fluke that repeated itself, perfect.

Anyways f.. that, there's something else I want to ask you. Why on earth would you be interested in finding out if Maha is accurate? Are you some kind of dyno critic? It's like I'm about to buy a house but first I wanna see for myself if the architect is as good as people say he is, so I run background checks on his technique, rather than just walk around the house see if I like the darn thing and make it mine. Better yet, it's like I'm having a frigid cold Starbucks Frappuccino but before taking my first sip, I wanna see for myself if the blending machine is as good as they claim, so I ask for specs along with a full demonstration of the blending process. I've been trying to understand your way of thinking since your first post and to tell you the truth, you are one of a kind.
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #93 · (Edited)
I guess it was a fluke that repeated itself, perfect.

Anyways f.. that, there's something else I want to ask you. Why on earth would you be interested in finding out if Maha is accurate? Are you some kind of dyno critic? It's like I'm about to buy a house but first I wanna see for myself if the architect is as good as people say he is, so I run background checks on his technique, rather than just walk around the house see if I like the darn thing and make it mine. Better yet, it's like I'm having a frigid cold Starbucks Frappuccino but before taking my first sip, I wanna see for myself if the blending machine is as good as they claim, so I ask for specs along with a full demonstration of the blending process. I've been trying to understand your way of thinking since your first post and to tell you the truth, you are one of a kind.
Theo,
In the interest of keeping the story as "short" as possible, I did leave out a few steps that DD took in determining the fixed % driveline figure which they used.
They definitely didn't just guess!!:)
if you tell me the vehicle involved, I can probably explain why they were within 3% of correlation with MSR500, in that particular case.
However, IF the Maha is as good as most of the British / European Tuners claim, it is a seriously far better approach, IF what you wish to know is Engine Power.
Of course, if one is happy to simply measure Tyre Power, as the Australian Tuning Industry has for over 50 years at least, then it is completely irrelevant.
A classic oranges / apples comparison.

With your attempt at analysis of my character, you will allow me to be seriously amused I hope? :)
You know your first example, with the Architect / House? If you add Builder, to your example, you are actually Spot On.
You aren't a psychologist by any chance are you?? :)
The coffee example is only an exaggeration because of item value.

I could of course, simply use a DD or Mainline in Tyre Power mode for the work I am about to undertake, as I have done for 50 years.
However, where is the fun in that?
I want to see if this (relatively) new fangled thing is as good as its German manufacturers claim!! :)

I'll leave you with another piece of info on my character.
You know perfectly well what our vehicles cost.
It is basically the same in both countries.

I have searched high and low for a used complete M139 Engine for months.
I have just about given up and am about to spend 10% of the vehicle's original cost on:-
Intercooler
Intake manifold
exhaust manifold
Turbocharger.
For investigative purposes.
Currently, i am debating whether to spend a further 10%, on just the cylinder head, bare. IE no cams, valves or any hardware.
MB Australia, REALLY know how to charge for spares.

You don't know a good European source for MB Parts do you?? :)
 

·
Registered
Joined
·
350 Posts
You're getting into all that trouble, not to mention expense, just for research, that's hot d4mn impressive and shows your kind of passion I was talking about in the other thread. In contrast, I would tune my car to 600hp for no reason other than haul ass. Boy do I seem primitive? It's like someone bought us a ball, you tear yours to pieces to see what it's made of, publish your findings and with the money that earns you, you buy another thing to broaden your knowledge. In contrast, I kick mine as hard as I can to see how far I can kick it, and eventually lose it.

Anyways, no I'm afraid I don't. I'm new to MB this is my first MB car, but I'm happy to say I've already acquired decent knowledge in nearly two years that I've been here. Boy was I like a fish out of water when I first got here, haha.
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #95 ·
You're getting into all that trouble, not to mention expense, just for research, that's hot d4mn impressive and shows your kind of passion I was talking about in the other thread. In contrast, I would tune my car to 600hp for no reason other than haul ass. Boy do I seem primitive? It's like someone bought us a ball, you tear yours to pieces to see what it's made of, publish your findings and with the money that earns you, you buy another thing to broaden your knowledge. In contrast, I kick mine as hard as I can to see how far I can kick it, and eventually lose it.

Anyways, no I'm afraid I don't. I'm new to MB this is my first MB car, but I'm happy to say I've already acquired decent knowledge in nearly two years that I've been here. Boy was I like a fish out of water when I first got here, haha.
Time for some technical / commercial honesty.

if you want a 600 to 700 HP Uber Hatch, trade your A45S on even a current RS3, let alone the 2022.
****, they are making 1350 HP out of these on E85, so what's 650 on on 98 RON?
So long as your use reputable suppliers like TTE, APR, or Dodson's on the Trans, it is doing it by the numbers.
So many have done it before you, all around the world, that absolutely no investigation or R&D is required.
It has all been done for you.

So, why don't I just do that?
Have you heard the expression, "it is not about the destination, its all about the journey"?
OK, that's me.
The question you need to ask yourself is, "who are you"?

The reason being, I can tell you that any of us attempting 650 HP on 98 RON from the M139 are in for a **** of a journey!! :)

So, why would I even bother embarking on this journey, given the trouble and expense almost certainly involved?
Those Mega HP RS3's are now what the Americans call " cookie cutters". ( IE just churn out duplicates)
In Australia we call them "Belly Button" cars.

Why, because everyone HAS one!! :)

I am prepared to pay to learn to be different.
No, I shall never make any money out of it.
Fortunately for me, I no longer need to!!
 

·
Registered
Joined
·
85 Posts
Yeah, the new RS3 yes, the old one - no way, purely because it handles/drives so badly.
If when I was buying, the new RS3 was available I would have probably jumped on it, the 5 cylinder is a brilliant platform. You can still do new things with it, just much easier.

The A45s Iam enjoying for what it is - a complete package. I have other 10second cars, still have my old xr6t which is surprisingly going up in value. Now that is a platform to modify! The A45s for me is more a daily runabout.

The A45s leaves my previous Focus RS for dead in a straight line. However, the RS was more fun to drive and handled a lot better. I want to see if we can mod the driveline of the A45s more than power hikes. Transform the A45s to 70% RWD and it will be awesome to fang about. Thats where a lot of the RS modders figured out, you could reprogram the RDU - ended up being the best mod and was free!
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #97 ·
Yeah, the new RS3 yes, the old one - no way, purely because it handles/drives so badly.
If when I was buying, the new RS3 was available I would have probably jumped on it, the 5 cylinder is a brilliant platform. You can still do new things with it, just much easier.

The A45s Iam enjoying for what it is - a complete package. I have other 10second cars, still have my old xr6t which is surprisingly going up in value. Now that is a platform to modify! The A45s for me is more a daily runabout.

The A45s leaves my previous Focus RS for dead in a straight line. However, the RS was more fun to drive and handled a lot better. I want to see if we can mod the driveline of the A45s more than power hikes. Transform the A45s to 70% RWD and it will be awesome to fang about. Thats where a lot of the RS modders figured out, you could reprogram the RDU - ended up being the best mod and was free!
Understand your comments about the current RS3 and I am certainly NOT going to defend its handling!!
However, a lot of the guys here seem to be into straight line performance and my point was just that the cheapest and simplest way to build a 650 HP on 98 RON hot hatch, was start from a RS3, even the current, ("unfortunate") handling model.

Had a number of Barra's personally, the last with just over 1000 HP on 98 RON at the tires. (DD Dyno).
Nothing now, I know; however a fairly big deal coming up to 10 years ago.
I normally never mention Barras though on international forums, as they are such an Aussie thing.
 

·
Registered
Joined
·
152 Posts
Discussion Starter · #98 · (Edited)
You're getting into all that trouble, not to mention expense, just for research, that's hot d4mn impressive and shows your kind of passion I was talking about in the other thread. In contrast, I would tune my car to 600hp for no reason other than haul ass. Boy do I seem primitive? It's like someone bought us a ball, you tear yours to pieces to see what it's made of, publish your findings and with the money that earns you, you buy another thing to broaden your knowledge. In contrast, I kick mine as hard as I can to see how far I can kick it, and eventually lose it.

Anyways, no I'm afraid I don't. I'm new to MB this is my first MB car, but I'm happy to say I've already acquired decent knowledge in nearly two years that I've been here. Boy was I like a fish out of water when I first got here, haha.

Theo,

Let's talk about aftermarket Tuning and what one can "get away with".

For a while you have heard me going on about " the length of time, at any one time, the vehicle is able to be held at WOT, Full Load"

Why is this important and how does it effect "Tuning"?.
It is all about Thermal Load Stability within the engine, particularly with respect to certain components in the Cylinder Head and the Pistons / Rings / Cylinder Block bores.

It starts with the fact that there are two forms of engine tuning.
1) The traditional manner and the way the OEM's still do it.
This is called "Step Tuning" and it involves holding the engine at a single RPM "step" until all engine operating parameters, both temperature and pressure have stabilised , recording the torque output, (HP is calculated from this), before moving onto the next RPM step.
You go right through the RPM range of the engine in this slow and time consuming manner.
(In steps of somewhere between 100 and 500 RPM, depending upon the accuracy the OEM is chasing).
The time duration of each step varies with many parameters; however I have never seen it be less than 30 seconds per step and frequently longer.
As I would hope you can see, this is very hard on the engine, extremely time consuming and requires a VERY well set up test cell.
(Usually with an OEM this is done on an engine dyno)
This process is from where the car companies obtain those sexy PR images with the turbo / exhaust manifold all glowing red.
This is how all OEM engine development is undertaken and how they generate the Power curves which they publish.

2) Aftermarket Tuning, known as "Sweep Tuning"
This simply involves accelerating the engine from some low rpm figure, through to redline, in a single "sweep", of somewhere between 6 and 12 seconds duration , depending upon the engine power being produced and the load being applied by the particular chassis dyno.
Sweep tuning is employed by almost all Aftermarket Tuners for two, very good, (to them) reasons
a) Their test cells are not set up to cope with the thermal loads created by Step Tuning. (You can imagine the heat coming off the engine, the way the car companies do it)
b) Most importantly, Sweep Tuning places so much less thermal load on the engine, that it substantially reduces the risk of damge to the engine during the tuning process and thus upsetting you, the customer.

Now, on the surface, this would appear to be a good thing, correct? After all, reduced risk to your engine seems like something everyone would want, correct?
Well actually no, it all depends upon how you want to use you vehicle.
If all you ever want to do, is apply full load for approximately the same period of time, or just a few seconds longer, than it spends on a sweep dyno run, then fine, go for it.

Which is from where my 12 seconds duration at WOT Full Load, at any one time, originates.

However, if you want to use you vehicle fore MORE than12 seconds at WOT Full Load, at any one time, then there are all sorts of issues involved.

Aftermarket Tuners, chasing the highest possible numbers for commercial bragging rights, are encouraged, simply by their Tuning methodology, to run more ignition advance and leaner Air/ Fuel ratios , (not to mention, MORE BOOST) than would ever be the case if they were Tuning using the OEM professional Step Tuning approach.
It can also cause them to miss a crucial ancillary parameter, such as fuel volume supply,. simply because of the relatively short sweep duration involved.
(Dynojet's are particularly bad in this regard and were directly responsible for multiple engine failures in competition events all over the USA ,until the Tuners using them caught onto the issues)

This time duration at WOT parameter, is why you can "get away with" running compressor overspeed (assuming mechanical integrity, of course), at ridiculous compressor discharge temperatures, for a few seconds. Along with many other "wrong" elements of the tuning process.

NOTHING in the engine has thermally stabilised in the few seconds for which you are applying WOT , Full Load, during a single Sweep Tuning Dyno run, or a 60 to 130 MPH Dragy run.
Which, unknowingly, is upon which you are relying to avoid grenading your engine.

Just don't go Mile Racing in Texas on a summer's day with that type of tuning, that's all !!!! :)

Or 1000M Racing on an Australian summer's day!! :)
 

·
Registered
Joined
·
350 Posts
Owners running maxed out setups also prefer downhill runs. Less load on their engine. But uphill is no problem for bigger engines.

Btw last night after my post #666 LoL on the General Tuning Thread, I went out for a fun drive and after putting it through a good beating, it was the first time the AC kicked in to cool down the engine. I remember reading about this but never seen it happen. So as I was doing one run after another, my usual sub 12 second runs, along with one time hitting the 7k limiter for a couple of seconds as I was distracted watching the road and missed the gear change (think I was in 3rd), I suddenly heard the AC briefly making its usual hissing sound as it kicks in, and I'm sure it wasn't me that turned it on. Furthermore, nothing came out of the vents. Fan was switched off too. So it's safe to say that it really happened, the ECU called the AC for a little help, to save the engine from evil Theo. Engine oil temp was at 106°C and gearbox at 93°C or so, but I remember I've seen these temps before, only no AC help was needed. Question is why now? Coolant was at 90°C so no change there, or so I saw it was, but I've heard from other owners (different make) that sometimes coolant may climb to even 100°C momentarily before the ECU does its thing and may not even register so the driver won't be able to know. So with oil temps being nothing out of the ordinary for spirited driving, perhaps it was coolant temp that caused it.

(edit: on second thought, the AC would intervene only to lower inlet temps if the IC can't cope, right? So I guess that's what triggered it)

Anyways, engine oil very quickly dropped to 95°C (gearbox took its time as always) and a little while after that it was under 90°C. Not sure at what point the AC was turned off, but only a couple of minutes after it kicked in, I did check my idle consumption and it was at 1L/h to 1.1 which I've seen before with the AC off. So I'm sure it wasn't needed for more than two minutes.

I'm glad it happened, now I know that that clever feature actually works!
 
81 - 99 of 99 Posts
Top