@andyay123 - I apologise if I'm about to insult your intelligence...
Before you tune, be aware of the consequences
Increasing power and torque will increase stress on the engine and other components. As such the consumables of both may "wear" more quickly. This means that it is wise to service a tuned car more frequently, but also to change certain "lifetime" components and consumable to service items. So for example gearbox ATF oil & filter ought to be changed at less than 38K intevals and it would be wise to have then hypoid oil changed at some point. It is also sensible to be aware of the weak points in the car because tuning might make them fail more quickly. On the B8 the DL501 gearbox is top of this list (the 3rd version fitted from 2103-ish is hopefully OK, but ones before that are at risk). Next is the crank pulley which is likely to fail at some point. On early engines the water pump wears out. On the newer engines (mid-2014 onwards) the supercharger clutch is a risk item. Ideally these risks should be mitigated (where possible) at the time of tuning, but if that's not done owners should be aware that tuning might accelerate failure.
Stage 1 vs stage 2
The OE ECU map restricts peak torque and power by opening a bypass valve in the supercharger to recycle the air and limit manifold pressure. In simple terms stage 1 raises the threshold of when this is opened. More air needs more fuel so the fuel map has to be changed. However depending on the tuner, other maps such as the spark timing can be tweaked. To increase torque and power beyond this, even more airflow is needed to increase manifold pressure. This is done by increasing the revs of the supercharger in relation to the engine revs. The OE pulley ratio is 2.56 so when the engine is at 7,200 rpm the supercharger is at just over 18,400 rpm. One way to change the ratio is to use a smaller supercharger pulley. It has been found that the smallest without risking belt slip is about 57 mm and this increases the ratio to 2.84 and the supercharger revs to just over 20,400 rpm. However the Eaton supercharger is spec'd to 24,000 rpm, so the ratio can be increased to 3.33 (for a 7.200 rpm redline). This can be achieved by increasing the size of the crank pulley, either on its own, or in conjunction with a smaller supercharger drive pulley (which is known as DP - dual pulley).
Stage 3
For completeness it should be mentioned that further gains are possible. An attempt was made at a supercharger upgrade but its benefits were never realised, especially given the price. The other solution is to increase maximum airflow further by removing the restriction at the throttle by increasing its size. I think the only commercial TB upgrade is from APR with their "Ultracharger" brand.
Tuning requirements
I think one of the biggest areas of confusion are about what else needs to be done as part of the tuning. I mentioned components at risk of failure above, and I'm going to ignore subjects like braking and suspension, and focus on things directly related to performance.
FUEL: In basic terms the octane refers to how "smoothly" the fuel burns. An engine which is tuned to do so can extract more energy from a higher octane fuel and this gives better torque. Most tuners program the ECU to do this, and so a tuned engine will have higher torque and power with higher octane fuel. However the engine should still cope with lower octane, it will "******" and run at lower power.
AIR: Increasing the manifold pressure in stage 1 and 2 is only possible if there is sufficient airflow to allow it. I have not seen any evidence, but it would appear that a stage 1 tune is not restricted by the OE intake, and certainly not at the OE redline. However I have seen evidence that stage 2 will be restricted at the top end and that's why intake uprating is always recommended for stage 2 (and a stage 3 larger TB is simply an extension of this uprating).
TRANSMISSION: Increasing the torque from the engine is only of benefit if it can be transmitted to the wheels. By definition the point in the transmission where loss of torque will be highest is at the clutches. The clamping pressure of the clutch packs is set by the TCU. There are many cases where tuning easily exceeds this OE pressure and there is slip (I believe the S3 is such a case). I believe that MRC has also seen it on the S4/5 which is why they recommend the TCU remap which increases the pressure. The other limit in the TCU is the redline. The B8 had this at about 6,800 rpm (I think) whereas the B8.5 was reduced to about 6,250 rpm. It is accepted that this platform can cope with around 7,200 rpm so most TCU remaps will increase the redline to this, releasing a bit more power.
EXHAUST: Unlike many platforms, it seems that the exhaust system on the B8 is not restrictive even at stage 2. However the cats are vulnerable to heat and may be restrictive at stage 3 so ought to be uprated or moved.
HEAT: Since hot air expands heat is an enemy of tuning (particularly forced induction). The heat exchanger system varies between the B8 and B8.5, and again for the CREC engine, so the situation regarding what uprating is needed is unclear. Of course actual running heat relates to how the car is driven. Uprating is recommended in stage 2 for hard driving and hot environments, and seems to be a requirement for stage 3.
Custom tuning
As I noted, any stage needs ECU reprogramming to change the engine maps. Without doubt there is skill to this and some tuners can optimise maps better than others. This has more impact the higher the gains. However also no two cars are absolutely identical, and a skilled tuner can optimise a map for a specific car. Most tuners use generic maps which were created on a development car. Other tuners (MRC being the prime example) will start with their generic maps but then tweak them for each car to create a custom tune which (in most cases) results in slightly higher performance.
As I'm sure other(s) have already suggested, this tuning game is addictive. @arad85 is currently considering adding an afterburner to the back of his S5 and even @jdp1962 is looking at intake kits. If you are sure that you only want stage 1 now, then I suggest you might think about the possibility of going stage 2 in the future, since you are likely to go back to the same tuner. Stage 2 at MRC is different from stage 2 at APR or stage 1+ at REVO. Then there's the question of what they would charge for an upgrade. That might be something you could negotiate on in advance.I only need stage 1 so now its just deciding between Revo, APR and MRC. I already have rear silencers arriving from BCS exhausts. I am swaying towards MRC to be honest. 2 hour drive compared to both Revo and APR on my doorstep.
As I'm sure other(s) have already suggested, this tuning game is addictive. @arad85 is currently considering adding an afterburner to the back of his S5 and even @jdp1962 is looking at intake kits. If you are sure that you only want stage 1 now, then I suggest you might think about the possibility of going stage 2 in the future, since you are likely to go back to the same tuner. Stage 2 at MRC is different from stage 2 at APR or stage 1+ at REVO. Then there's the question of what they would charge for an upgrade. That might be something you could negotiate on in advance.
If I could... I wouldAs I'm sure other(s) have already suggested, this tuning game is addictive. @arad85 is currently considering adding an afterburner to the back of his S5
I've opted for a Forge intake, this one. It'll be fitted in about five weeks time, when the car gets its MOT, an interim engine oil & filter change plus an early gearbox oil and filter change.
All being done at local independent.Good choice @jdp1962 .
A quick question (if you don't mind me asking) for the gearbox and filter change you going back to the stealership or using your local garage?
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Tash, are you undecided where to get yours done? Just don't go to this place...
@andyay123 - I apologise if I'm about to insult your intelligence...
Before you tune, be aware of the consequences
Increasing power and torque will increase stress on the engine and other components. As such the consumables of both may "wear" more quickly. This means that it is wise to service a tuned car more frequently, but also to change certain "lifetime" components and consumable to service items. So for example gearbox ATF oil & filter ought to be changed at less than 38K intevals and it would be wise to have then hypoid oil changed at some point. It is also sensible to be aware of the weak points in the car because tuning might make them fail more quickly. On the B8 the DL501 gearbox is top of this list (the 3rd version fitted from 2103-ish is hopefully OK, but ones before that are at risk). Next is the crank pulley which is likely to fail at some point. On early engines the water pump wears out. On the newer engines (mid-2014 onwards) the supercharger clutch is a risk item. Ideally these risks should be mitigated (where possible) at the time of tuning, but if that's not done owners should be aware that tuning might accelerate failure.
Stage 1 vs stage 2
The OE ECU map restricts peak torque and power by opening a bypass valve in the supercharger to recycle the air and limit manifold pressure. In simple terms stage 1 raises the threshold of when this is opened. More air needs more fuel so the fuel map has to be changed. However depending on the tuner, other maps such as the spark timing can be tweaked. To increase torque and power beyond this, even more airflow is needed to increase manifold pressure. This is done by increasing the revs of the supercharger in relation to the engine revs. The OE pulley ratio is 2.56 so when the engine is at 7,200 rpm the supercharger is at just over 18,400 rpm. One way to change the ratio is to use a smaller supercharger pulley. It has been found that the smallest without risking belt slip is about 57 mm and this increases the ratio to 2.84 and the supercharger revs to just over 20,400 rpm. However the Eaton supercharger is spec'd to 24,000 rpm, so the ratio can be increased to 3.33 (for a 7.200 rpm redline). This can be achieved by increasing the size of the crank pulley, either on its own, or in conjunction with a smaller supercharger drive pulley (which is known as DP - dual pulley).
Stage 3
For completeness it should be mentioned that further gains are possible. An attempt was made at a supercharger upgrade but its benefits were never realised, especially given the price. The other solution is to increase maximum airflow further by removing the restriction at the throttle by increasing its size. I think the only commercial TB upgrade is from APR with their "Ultracharger" brand.
Tuning requirements
I think one of the biggest areas of confusion are about what else needs to be done as part of the tuning. I mentioned components at risk of failure above, and I'm going to ignore subjects like braking and suspension, and focus on things directly related to performance.
FUEL: In basic terms the octane refers to how "smoothly" the fuel burns. An engine which is tuned to do so can extract more energy from a higher octane fuel and this gives better torque. Most tuners program the ECU to do this, and so a tuned engine will have higher torque and power with higher octane fuel. However the engine should still cope with lower octane, it will "******" and run at lower power.
AIR: Increasing the manifold pressure in stage 1 and 2 is only possible if there is sufficient airflow to allow it. I have not seen any evidence, but it would appear that a stage 1 tune is not restricted by the OE intake, and certainly not at the OE redline. However I have seen evidence that stage 2 will be restricted at the top end and that's why intake uprating is always recommended for stage 2 (and a stage 3 larger TB is simply an extension of this uprating).
TRANSMISSION: Increasing the torque from the engine is only of benefit if it can be transmitted to the wheels. By definition the point in the transmission where loss of torque will be highest is at the clutches. The clamping pressure of the clutch packs is set by the TCU. There are many cases where tuning easily exceeds this OE pressure and there is slip (I believe the S3 is such a case). I believe that MRC has also seen it on the S4/5 which is why they recommend the TCU remap which increases the pressure. The other limit in the TCU is the redline. The B8 had this at about 6,800 rpm (I think) whereas the B8.5 was reduced to about 6,250 rpm. It is accepted that this platform can cope with around 7,200 rpm so most TCU remaps will increase the redline to this, releasing a bit more power.
EXHAUST: Unlike many platforms, it seems that the exhaust system on the B8 is not restrictive even at stage 2. However the cats are vulnerable to heat and may be restrictive at stage 3 so ought to be uprated or moved.
HEAT: Since hot air expands heat is an enemy of tuning (particularly forced induction). The heat exchanger system varies between the B8 and B8.5, and again for the CREC engine, so the situation regarding what uprating is needed is unclear. Of course actual running heat relates to how the car is driven. Uprating is recommended in stage 2 for hard driving and hot environments, and seems to be a requirement for stage 3.
Custom tuning
As I noted, any stage needs ECU reprogramming to change the engine maps. Without doubt there is skill to this and some tuners can optimise maps better than others. This has more impact the higher the gains. However also no two cars are absolutely identical, and a skilled tuner can optimise a map for a specific car. Most tuners use generic maps which were created on a development car. Other tuners (MRC being the prime example) will start with their generic maps but then tweak them for each car to create a custom tune which (in most cases) results in slightly higher performance.
Tash, are you undecided where to get yours done? Just don't go to this place...
it seems potentially wise to NOT go there if you have a tune?
^^^ You said it yourself. Tune or not you should go to stealers only until the car is under warranty or if you have spare / too much money to throw away.
I tuned my S4 while it still had few months warranty left on it. The car has been with them twice since; once for a full service (I got two free when I bought the car) and washer jet replacement. For any future work the car will either go to MDM Technik or MRC.
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Hmm, I never know about resale value and the benefit of a full Audi service history
That depends on the reputation of your local dealer, mine is rubbish.
I doubt many people look at who did the servicing though right? If it’s Audi most people are happy I imagine. Obviously people here will be an exception that that perhaps.
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Hmm, I never know about resale value and the benefit of a full Audi service history - seems wise to have. I suppose if you have a tune that kinda goes out the window anyway.
Are MDM well known in the forums or just that they’re local to you? Would be keen to use someone who is trusted if I move away from Audi themselves, garages annoy the hell out of me - every one gives you a different opinion so never know who to trust! Need someone local to Nottingham who is good.
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I only have experience of selling one tuned car, my B5 S4. Due to its age I don't think FASH was a problem for commercial resale (e.g. the dealers who offered me a ridiculously low trade-in before even asking about history). I sold it privately and to an enthusiast
But I hope that when the cars get to 5+ years old they will be seen as very affordable with 450hp+, in comparison to the price of cars like the RS4
Thanks for all your experience. Invaluable.I'm not a typical case I think. The first potential buyer approached me at a petrol station and asked about my car. It was that contact which started me thinking about selling it. So I stayed in contact with him and so several months later I asked him if he was interested in buying and he was. However it seemed that his level of "interest" may have been insufficient for him to actually proceed. So I then advertised the car on the forums and found the second buyer very quickly. But note that this was a 13 year old B5 S4 which I sold for £3500 IIRC, so doesn't relate well to our cars!
I have to say that I have tuned my S5 completely oblivious to its resale value. That's because there is every chance that I will keep it a long time. Although I proposed 5+ years above, for me I imagine that mine will be at least 6 years old before I consider selling, and probably older, depending of course what I'd want to replace it with. By that time I will have had my fun and accepted the depreciation (especially considering that the list price was £52K but with discounts I paid £43K) and so if I fail to find an enthusiast I'll accept what I can get. However in your case if you are really sensitive to the resale value because you might be in a position where you need to sell, I'd advise not tuning. When you sell a tuned car and want an enthusiast to buy, you need to be in a position to wait.
The first potential buyer approached me at a petrol station and asked about my car
for me I imagine that mine will be at least 6 years old before I consider selling
That's a good question. I may have stated on this forum before that I followed the same strategy as my B5 S4: It was one of the last B5 S4's made, and so (as far as possible in economic/marketing terms) Audi should have fixed its major problems. And it had a good history of tuning to several stages with plenty of information on the forums to judge the likely consequences of that tuning. So I got a stage 1+ tune on my B5 (remap and full Milltek) with a good level of confidence on longevity (although I was already ready for the risk of turbo failure because turbos have a broad longevity curve). I had that car for about 13 years (11 of them tuned) with no major problems - including the turbos.So I suppose then you are quite confident in the longevity of MRC stage 2?
Assuming the 215 you're being quoted is PS, then that's a 21.5% increase. That's proportionately a higher gain than I got for my £600; my S4 went from 333PS to 393PS (386BHP) which is an 18% gain. Only you know if it's worth the money, but I'd be surprised if you weren't happy with the outcome.That's my feeling too, I like to see where my money is going...
They are also recommending the gearbox remap which sounds sensible.
Still wondering if the extra 40 odd horses would be worth the money..
That's what I was thinking, the search for a provider continues...I'd be surprised if you weren't happy with the outcome.
Correct me if I'm wrong but I think the new MOT standard for emissions is specifically for testing DPF's on diesel cars?Does Stage 1/Stage 1+ affect emissions? Are modified cars at significant risk of MOT failure due to emissions in particular with new standards set to come into play?