Chipping

[TurkS4]

I know there are some discussions regarding chipping and the resulting torque/BHP increase. However, as I am not familiar with what this means, can you please tell me in MPH terms what the gains are in comparison to unmodified.

Is 0-60 quicker and is the top speed in the 170mph bracket etc.

I would like to get a feel for what this all means before I potentially undertake a mod chip.

I have just upgraded from a 2.8 quattro to a S4, so any input would be appreciated.

Cheers

[img]images/graemlins/beerchug.gif[/img]

[Bushy]

Welcome

Well come to Castle Coombe on 2nd April and you will surely understand

Alternatively come to a meet, i believe there is on in Windosr at the end of the month

[TurkS4]

How can I find info in regards to Castle Coombe or the meet in Windsor?

Thanks [img]images/graemlins/thumbs.gif[/img]

[Joshie]

A simple remap (or chip) will raise the power by about 16% and torque by about 23% although the actual achieved will depend upon the characteristics of your particular engine

In addition the speed limiter which is normally set at about 150ish is removed allowing the car to reach it's maximum speed where conditions and the law permit [img]images/graemlins/grin.gif[/img]

A remapped S4 accelerates faster than standard - from 5.6s to 60 mph in standard guise to about 4.9s after the remap.

The car is also more drivable with the torque normally coming in much lower down the rev band. Fuel consumption is also reduced, how much depends on your driving style. [img]images/graemlins/033102bigblink_1_prv.gif[/img]

[Joshie]

How can I find info in regards to Castle Coombe or the meet in Windsor?

Thanks [img]images/graemlins/thumbs.gif[/img]

Have a look under "trackdays and meets" in this site

[Dippy]

To add to Joshie's reply, this is the more technical description:

The torque of an engine is effectively the force it produces in order to shove the car forwards. It is related to the quantity of air and fuel in the cylinders. The S4's turbos pressurise the air so that this increases. This is why your S4 can give you a getter "shove-in-the-back" feeling for a 2.7l engine compared to your old 2.8.

Power is the rate at which the torque does this shoving, so as the engine revs go up, so does the power.

The engine is controlled by a computer called an ECU, and one of its jobs is to make sure that the fuel is increased as the turbos push more air into the engine. It does this using an n-dimensional "look-up" graph called a map.

When Audi made your S4 they decided that the 'top' of the map should be when the turbos are producing about 0.8 bar air pressure. As a result the engine gives a maximum of 400Nm torque and 265bhp power.

However the engine is very strong (except for some parts like the TBB), and can take more. So by 'chipping' a tuner can put a new map into the ECU, extending the top end. Typically a stage 1 tune will take the S4 to about 500-510Nm torque and 300-320bhp power.

So, as you ask, what does this really mean?

Top speed: This is dictated by the max engine revs in top gear. So it can only increase if the max revs do. It is common for the tuner to remove or increase the rev limiter, so indeed the top speed may increase. Others can tell you if, and by how much it might increase, as I'm afraid I'm not really interested in top speed. Of course the engine is also likely to produce more torque at max revs, so getting to, and maintaining top speed would be easier.

Acceleration: This is directly proportional to torque, so after a remap the car will accelerate quicker.

0-60: It will be quicker, but of course that depends on gearchange since you can't really do 0-60 in one gear. So without a short-shifter as well, your benefits might be lost. Also the increased torque will put more stress on the clutch and gearbox, so reliability will suffer (eh, Joshie?)

[Joshie]

Presented like a true enthusiast Dave.

...and regarding your last point [img]images/graemlins/nodder.gif[/img] [img]images/graemlins/033102bigblink_1_prv.gif[/img]

[TurkS4]

Many thank chaps....great site with some very knowledgeable people around!!!! [img]images/graemlins/thumbs.gif[/img]

[toasty]

Congrats on the upgrade mate, I too went from a 2.8Q to S4 and I've never looked back. [img]images/graemlins/colflash.gif[/img]

The S4 is a superb car. [img]images/graemlins/thumbs.gif[/img]

As for chipping increasing top speed, sure it will, but if you push your standard S4 then you'll be surprised how fast it will go, I've been told that they'll sail past the 155mph limiter no worries. I think 170mph is probably attainable by a standard S4. [img]images/graemlins/blush.gif[/img]

-Dan

[wazza]

I think 170mph is probably attainable by a standard S4.

I'm not so sure. In standard guise, it does not have the power/torque above 6k rpm to push against the force of the mass of air you have to cut through. [img]images/graemlins/confused.gif[/img]
Anyone agree? [img]images/graemlins/spineyes.gif[/img]

[Golich]

I'd be supprised if a stock S4 could do 170mph.

I've had 167mph on the flat on my 323bhp chipped S4 and it was slow getting there after 145mph. I did this over about a 2-3mile blast. It will definitely do 170mph but not much more. However, if you got a stock S4 going down a hill you might well get 170mph. I used to get 139mph on an Orion injection 10 years ago just before the rev limiter cut in - that was a bit of a twitchy experience [img]images/graemlins/blush.gif[/img]!

The problem is as correctly stated above. The drag force on the car increases exponentially at a rate of the velocity squared. This is why you need serious ponnies to break the 200mph mark. i.e. force to push the car through the air = 1/2*density of air*drag factor*Velocity^2. So you can see all things equal at:

10mph the force is 100 times that of say 1mph. i.e. 10^2
at 100mph the force is 10,000 times that of 1mph
at 150mph the force required to push the car is 22,500 times
at 170mph the force required is 28,900 times.
at 200mph the force required is 400,000.

Sorry I'm getting carried away. I've been working on ocean wave fluid loading calcs all day. [img]images/graemlins/spineyes.gif[/img]

[DavidR]

Regards to top speed, bear in mind that the speed on the speedometer is not a true reflection of you actual speed. If you figure that an average speedo over reads by 8-10% then if you are doing an actual 150mph, the speedo will be showing anything from 158-165mph. This deficit increases with speed obviously, so you may only be doing 155-160mph for the speedo to read off the scale at 170mph+
and I beleive that an early road test of the S4 had the reoporter raving about a 170mph run...

I compared mine to a GPS speed reading and at an indicated 160mph, the GPS read 149mph (boo hiss!!)

[tombs]

Having just read the last post, I did a while ago have a blast at Elvington Airfield, one of the longest runways in the World according to the guy that owns it, over 4 mile stretch! And I seemed to get my S4 to go over 160 M/P/H, but as the last post says it did bounce about a bit (speedo not car!) Thought I was doing well in the 0-60 area, when a customer bought his twin bike engined Tiger along and blew me to pieces!! Was with him at Zolder 2 years ago and he managed to break the record 0-60 in under 3 secs!!! He isnt happy with that and has installed a four wheel drive system and a motec engine management system, 0-60in 2.8 Secs !! 0-100 in 6.3!!!!!!!!!!!!!!!! [img]images/graemlins/033102scull_1_prv.gif[/img]
Now thats acceleration!
[img]images/graemlins/thumbs.gif[/img]