Why does Abt not offer chip tuning for induction engines?Following the discussion's on the D_S thread's regarding what bhp was achievable i want to find out what are the real world gains to had with the RS4 Engine?
I have a vested interest in the cars i own and i joined this forum primeraly to find out what engine mod's were around and what gains they were getting. I was due to have D_S upgrade my ECU at the group buy but for me they were not achieving the gains i was expecting so i decided not to have it done, now thats not to say they are not achieving what was posted at other times.
It seems there are very few tuners able to gain any additional HP from this engine through remaps alone.
ABT Sportline are a race-tuning company that specialise in Audi's, they race in the DTS championships and are currently leading. Heres what they say to an ECU upgrade for the RS4.
Ok so thats just one company's opinion right, wrong. As a comparison Dinancars in the US build BMW race engines, they are a tuning company and they don't offer ECU upgrades on the M3 or M5. What they do offer is, New throttle bodies but no remap alone, and the gains on a 500hp engine are;-Chip tuning alone does not bring any considerable power advantages for Otto-induction engines (engines without turbocharger). There are simple explanations for this: An Otto-engine requires a defined fuel-air mixture for combustion. No influence by means of the ECU can be taken on the air flow and thus the aerator proportion in the mixture. A possible alteration of fuel quantity therefore only brings about a noticeable increase in performance if a mechanical optimization is carried out at the same time (e.g. air intake, camshaft, pistons, valves, etc.)
Peak Horsepower Gain: 13 @ 8100 rpm
Peak Torque Gain: 8 lb-ft @ 8100 rpm
Now there's been alot of talk about dyno plots not meaning much and its all about The Butt Dyno. So is this what your Butt's telling You?
This is from http://dinancars.com/whitepapersFile.asp?ID=9
SR71's ReplyI believe that the rather large horsepower gains that are being published by some, particularly with regard to "power chips", are the result of tuning the cars back to the stock mixture and ignition timing settings, essentially leaning-out the air/fuel mixture and advancing the timing to compensate for the rich mixture and retarded timing experienced on the dyno. It appears to me that this "increase" in power is then included in whatever gains were actually achieved (if any). In reality, these supposed gains are nothing more than a correction for the testing conditions, resulting in an exaggerated performance claim. In addition, many "power chips" create the perception of an increase in power/acceleration as the re-programming will often dramatically increase the speed of the throttle opening on the drive by wire cars, making the engine feel more powerful
I made my post in the DMS thread (http://www.rs246.com/index.php?name=PNp ... 5&start=25) on the basis of your post above which was originally posted to that thread.
Funny how my conclusions (independently arrived at I might add) are close to what Dinan are saying...
There is nothing clever (in my opinion) about leaning out a mixture back towards stoichiometric (and advancing the ignition as a result) in order to generate more power.
That is just basic chemistry.
What is clever is the following (taken from the same Dinan site):
Now that engine control systems have advanced so dramatically, manufacturers can better manage conditions that might otherwise result in engine failure and they can produce more power per cc than ever before. While maximum horsepower has increased, so too has the variability of power output. This is because the engine control systems save the engine from failure by backing off power when conditions are less than ideal. This variability comes from the control system striving to extract whatever power is available, under a given set of conditions.
i.e., Power is sacrificed for reliability/longevity - a better overall package.
I like the following admission:
And in the case of performance engine management software for later model cars, we seem to be the only BMW tuner that has come to grips with the fact that there is simply no horsepower to be gained from engine management tuning alone.
It concurs with my suspicion that ECU mapping these days is so complicated, you've got to be a true guru to extract any more power from a NA engine over and above what the designer has done.
If you could, the designers would have, or alternatively, you've compromised the design in another aspect somehow.
For example, in turbo-charged cars you typically adjust the boost....at the expense of your turbo's life.
Ultimately I might go for increased power but I reckon I'm far more likely to go for MTM's supercharged package rather than a few additional horses via an ECU map.
If I'm going to blow the ****** up I want to do it big style.
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