How much power does a 35 iS have ?

Mavster · Post by **Mavster** » Sat Jul 11, 2020 4:56 pm

I have a dyno showing over 351 HP yet BMW can't see any sign of a remap !

I thought a standard car makes 340HP, so the only answer left is that they actually make more than BMW quotes??

keving1 · Post by **keving1** » Sat Jul 11, 2020 5:10 pm

It is possible that it is making 351hp or it could be that the Dyno is not accurate and reading higher than the actual figure - this is only 3% inaccuracy.

Maniac · Post by **Maniac** » Sat Jul 11, 2020 5:11 pm

Dynos can be subjective to calibration and other variables such as environment, a card engine age and quality, fuel and much more.

I was always told to take dynos with a pinch of salt as results can vary.

OEM power stats are approximate and could be more or less than stated.

Power values as bragging rights are for kids. What matters is drivability.

ColinBR · Post by **ColinBR** » Sat Jul 11, 2020 5:39 pm

They do tend to make more power than stated.
BMW mark them lower so that they dont take sales away from their higher marks. Ie M cars.

Mavster · Post by **Mavster** » Sat Jul 11, 2020 7:07 pm

Great, it certainly pulls hard when required

kinger · Post by **kinger** » Sat Jul 11, 2020 7:53 pm

Plenty enough....

Stevo1987 · Post by **Stevo1987** » Sat Jul 11, 2020 9:13 pm

They make more than my missus can handle. Frightens the bejesus out of her and I’m a fairly sedate driver, especially with her in the car.

buzyg · Post by **buzyg** » Sat Jul 11, 2020 9:34 pm

I would just enjoy the extra ponies.

ronk · Post by **ronk** » Sat Jul 11, 2020 9:40 pm

buzyg wrote: ↑Sat Jul 11, 2020 9:34 pm I would just enjoy the extra ponies.

Then after a while you would only want more!
I sometimes get tempted but most of the time in the UK I just potter about and do the odd brisk overtake to remind myself just how nippy the car is.

Pbondar · Post by **Pbondar** » Sat Jul 11, 2020 9:46 pm

A few pertinent points...

The power quoted by the manufacturer is the nominal power measured at the crankshaft not driving a gearbox and transmission without alternator /air con etc

Almost all dynos accessible by the public are inertia roller versions that measure power at the rear wheels through accelerating the rollers and then see how quickly the rollers slow down as the car coasts post acceleration..

They then use mathematics to predict what power at the crank would have been taking into account the coast down.

There is an international standard to normalise different dynos ...

As others have stated the only real benefit without lots of other corroborating information is to compare either one engine being tuned or two engines back to back on the same day on the same dyno..

Temperature, humidity, pressure as well as internal calibration factors are all variables that could render figures to be suspect..

Since computer controlled turbo engines arrived it’s very much in the gift of the manufacturer to vary the real bhp figure from the stated one for many reasons..

Also the max power may be affected by the quality of fuel with some engines automatically taking advantage of better quality fuels..

So 351 vs 340 is really in the noise relatively speaking..

buzyg · Post by **buzyg** » Sat Jul 11, 2020 9:55 pm

ronk wrote: ↑Sat Jul 11, 2020 9:40 pm
buzyg wrote: ↑Sat Jul 11, 2020 9:34 pm I would just enjoy the extra ponies.
Then after a while you would only want more!
I sometimes get tempted but most of the time in the UK I just potter about and do the odd brisk overtake to remind myself just how nippy the car is.

Exactly what I did today Sir.

ronk · Post by **ronk** » Sat Jul 11, 2020 10:16 pm

buzyg wrote: ↑Sat Jul 11, 2020 9:55 pm
Exactly what I did today Sir.

I’ll be doing the same later in the week!
The only time the car can be used near to Its potential is on trips to Germany- however as time goes on they apply more and more speed limits!

sunnydays · Post by **sunnydays** » Sat Jul 11, 2020 10:53 pm

Not enough

Stage 1+ MHD the car and really feel what the N54 has to offer. You will look back and regret driving it stock for so long.

Busterboo · Post by **Busterboo** » Sun Jul 12, 2020 11:06 am

Try to take my 35iS to 7k revs in several gears at least once a week. Do this 'manually' (paddles and/or stick) in Sport+ and the DCT contributes to the performance with the speed of its changes, not least by facilitating accurate use of the rev counter.

Lucky to live where there are roads that enable the car to be used to its performance in its lower gears and nearly in its higher. As a result, know, for example, maximum comfortable cruising with roof down (35mph less than nominal top speed).

In other words, wring the car out regularly. In doing so, find power enough.

ronk · Post by **ronk** » Sun Jul 12, 2020 12:16 pm

I’m afraid I can’t really appreciate the cars higher speed capabilities in the UK - a trip up to the 120mph you suggest then back to 70 doesn’t float my boat. Using the car on the Autobahn however, does generally allow for decent spells of 120mph motoring - when the limits dictate 70/80 it feels like a walking pace.

Just watch out for the odd Brit on the road who still hasn’t learned about lane discipline

(They are there to test your brakes)

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