Lost BHP

[zoros]

So I'm coming up behind what looks like a 2014 Series 1 BMW M Sport. Quite a boring looking vehicle and nothing unusual on it.
The car in front of the Beemer, moves over and the beemer floors it. I follow suit, just to enjoy the feeling of 'reeling' a young pretender in!
The Beemer, starts to pull away from me and I look in, I'm in 4th and passing 4000RPM and still the beemer is gaining ground on me.
I'm at the top of my torque curve and this family hot hatch is "farting in my general direction".
Suddenly - I wake up this morning realising, I have fallen out of lurve with my AMG.

So the question is: "assuming the Beemer was standard, how much HP would the old SL 55 AMG have lost over the last 15 years?"
[63k on the clock, serviced to within an inch of its life].
I'm guessing (based on what happened) she must have lost 100HP, maybe?

If that is the case, does a standard rolling road tune up, recover any of this lost power, or will I have to commit to chipping the ECU, changing the S/C pulley etc etc...?

Your views appreciated.

 

[developer]

Regardless of the nippy Beemer, I'd get your car on the dyno at MSL - the reason being there are loads of benchmark 55's that have been on Acid's dyno - you'll be able to get a good comparison.

You need that baseline before moving on, IMO.

 

[renault12ts]

You soon learn in big heavy old cars not to have a go at everyone...saves red faces.

 

[JohnBell]

4th and passing 4000rpm - try 2nd or 3rd next time.

 

[Suky Sangha]

Something's not right with your car. Mine is a standard 55k cls and have not been bothered by any BMW when driving a bit lively on a stretch of empty motorway. That's m powered bmw's. Unless that BMW was highly tuned?

 

[renault12ts]

4th and passing 4000rpm - try 2nd or 3rd next time.

Good point...op what speed were you doing at that point?

 

[ph47mf]

regardless of your car's age and how much power it has lost over the years, it shouldn't lose to a 1 series. I'd get it checked out.

 

[zoros]

Speed was "high". The car may have been a 135M. Couldn't get close enough!!!

 

[renault12ts]

The M140i will do 0-60 in less than 4.6 seconds. The SL55 in the same. So, given that you aren't brand new...

 

[zoros]

I see on another thread, lot's of talk about dyno testing. Who is the best in the country for tuning an SL55 AMG?

 

[daveenty]

As you're based in N Wales, MSL Performance would be suitable for you. About an hour and a half from Wrexham, traffic dependant. Developer mentions them in post #2.

They do know what they're doing.

 

[renault12ts]

But is there really a problem...the BMW M140 (if that's what it was) is a very hot little car, so even if the SL was on song there would be nothing in it.

 

[bluestreak]

Remapped m135i can push about 375bhp, which is about 260bhp/tonne. SL55 when new is about 251bhp/tonne taking into account optimistic 1964kg kerb weight. It isn't at all surprising beemer could pull away. I've pulled a few surprises like that in my 250bhp/tonne focus st with 460lb/ft in 3rd gear.

 

[John]

I also suspect it's simply your numbers aren't up to the job anymore.

Get yourself some headers, De-CAT, smallest EC pulley, uprated HE and IC pump and a proper remap from MSL to crank you up to hopefully 320BHP/ton and open a can of whoopass on a lot more of your competitors.

 

[Scott_F]

So engaged in a road race and lost. So what ?

No matter what car you drive and what you do to it there will always be cars on the road quicker than yours. So what ?

So you could just forget all the rolling road, ECU and pulley bobbins, save yourself a small fortune and still enjoy driving your performance car.

 

[Doc matt]

You were in 4th, he probably changed down to third and floored it so he had a head start. I wouldn't worry about it, I couldn't catch a Ford Focus the other day and I was in the Atom. :fail

 

[Bobby Dazzler]

It gets worse. There are fast diesel BMWs too. Very fast ones. I saw a 2017 Alpina D3 Bi-turbo at full chat today, and that could really shift. Handsome too.

 

[zoros]

Scott F - bang on. my faith is partially restored when you said that and I saw the car in the sun with the roof down.
Loved the poster who owns an Atom, you lucky lucky petrolhead. Can you imagine the driver of the Focus, beaming from ear to ear and he's probably down the pub right now telling everyone what he did the other day!

You are right though, it's all about timing, the right rev range, momentum, driving ability.
I used to work for the cops as a pilot and in return for the odd flight, they took me out in the interceptors occasionally.
When you are in the presence of genius - you never forget. They used various unmarked cars (mainly 335d BMW's) and my God the tactics they utilised and the ability to place the car exactly where they wanted it - was stunning. Nothing, literally nothing could get away. Braking was just as important as accelerating.
Even after 3 years of ownership with the SL55 I am still alternating between manual and shift stick settings. Far superior to fully automatic!

Thanks for the very interesting replies guys - appreciated.
Z

 

[zoros]

Final request.
Stock SL55 AMG, 2002.
How much would it cost for a standard re=map and change of pulley?
Excuse my ignorance - does the pulley change include the S/C clutch?
So I go into a dyno tuners and come out - how much poorer?
What sort of HP extra could I expect for my money?

 

[AMGeed]

Final request.
Stock SL55 AMG, 2002.
How much would it cost for a standard re=map and change of pulley?
Excuse my ignorance - does the pulley change include the S/C clutch?
So I go into a dyno tuners and come out - how much poorer?
What sort of HP extra could I expect for my money?

If your car is producing a stock 493bhp having an 83mm pulley (clutched) and a remap should put you in the region of 540 -550bhp. Prices change but if you budget somewhere in the region of £700 - £800 you wouldn't be far off.

Go a little further with a 77mm pulley and you are close to 600bhp but costs are a little more + you will be advised to have extra cooling (larger HE and new IC pump)

As mentioned by Dave and John above, Acid at MSL is the guy to go to and will also check your IAT's to see if your IC pump is working efficiently and give you before and after dyno figures to show the increase.