06 z4 si dyno run 234hp ?

[ChrisPDuck]

Hi guys new owner of z4 si 06 had a dyno and as the title states only put out 234hp it’s the N52B30 engine
Confused for the under power pulls very well again I’m new so could someone maybe shed some light on why this may be the case I know being a 56 plate the car is 12yrs old but has service book and been serviced regularly the only thing I’ve read up on is the difference in the coil packs does the sport need 14v ?
Is it possible someone could have put 12v would that drop power to the engine runs really smooth when I stop it feels as though the engine isn’t even running till I lift the clutch lol
Any help much appreciated
Thanks guys

 

[metal licker]

Hi and welcome to the forum
Can't help with your problem but I'm sure someone will be able to help

 

[ChrisPDuck]

Thanks for the welcome
I hope so won’t let me post a video of the dyno either which is a bit of a bother do love my new z4 had a remap done that had pushed it up to 294hp but if the base was supposed to be higher at 265hp would have mapped higher I have a print out of the dyno which I’ll post when I’m home
Cheers guys

 

[Z4 COUPSTER]

Hi is that power at the wheels? If so it's about right for age mileage drop off through gearbox and prop.
Manufactures quote bhp at engine not final drive.
Hope this helps and Welcome to Club Coupe!
D

 

[Z4 COUPSTER]

294bhp with remap? I was under the impression 289 bhp was MAX.
Forgot to add if it's remapped the torque I believe is altered a lot you lose some grunt higher up.
Others who have had done will know more.
D

 

[ChrisPDuck]

Thanks for you replies guys I have the dyno print out I’ll post it later it does feel faster on acceleration for sure top end I’m not brave enough on the road to try lol

 

[ChrisPDuck]

Sry yes that power was at the wheel of dyno

 

[Bodyboarder]

So you started at 234 at the wheels ( which is very good anyway as you loose quite a bit through the drive train ) and then a remap has gained you 294 ... a 60bhp gain . There’s something very suspect about that . A n/a from a remap producing 60bhp more ....I’ve never seen that .

 

[ph001]

Hub dyno is the only thing that is even going to be close to an accurate figure - roller dynos have far too many variables. I think you should totally forget the figure you got and also forget that any kind of remap can give you the figures stated on a 3,0Si. You are throwing your money away.

 

[ChrisPDuck]

I was told by my tuning guy who is a good friend and I’ve used him on many cars I’ve had to ignore the figures on n/a he said it should be around 20hp increase on the map
But I have the print out at home and he was happy with the results and so am I , I was just a little confused with manufacturers specs but I understand now first z4 I’ve owned as I said I’m usually a turbo guy

 

[Smartbear]

Hi, how many miles has your si covered? You could also be losing some bhp due to the rear silencer being removed
Rob

 

[ChrisPDuck]

On 55k now smartbear would the back box delete loss the z4 power then sounds little deeper that’s all really haven’t noticed a loss in power since work was carried out
Thanks for reply

 

[Smartbear]

On 55k now smartbear would the back box delete loss the z4 power then sounds little deeper that’s all really haven’t noticed a loss in power since work was carried out
Thanks for reply

It can do, someone posted on here a while ago who had a power loss after the backbox was removed :?
Rob

 

[Smartbear]

294bhp with remap? I was under the impression 289 bhp was MAX.
Forgot to add if it's remapped the torque I believe is altered a lot you lose some grunt higher up.
Others who have had done will know more.
D

That doesn’t make any sense? Horsepower is torque x revs, so to lose grunt higher up = loss of horsepower
Rob

 

[z4pilot]

Can't really help with your question beyond what's already been said, but Aero front on a coupe...

 

[ph001]

You also have to remember that a lot of the, shall we say, less reputable remap places can easily make the dyno figure say anything they want it to say as there are lots of hidden variables you can modify (like gearing and drivetrain losses). So do your first pre-map dyno run, then tweak one of the variables and do your second after the remap. Voila, 20bhp more. Happy customer, happy remap man. Just how hard you strap the car down to the rollers can make up to 15% difference on the result.

A lot of these internet startups are selling copied software maps at £300 a pop. The whole industry has become a bit of a minefield to be honest.

I wouldn't trust anyone that has been around for less than 10 years. Ideally they should have with some motorsport background.

Hub dyno are far less prone to error. It's the only type I would consider using.... http://www.cskdyno.co.uk/html/dynapack.html

 

[Z4 COUPSTER]

294bhp with remap? I was under the impression 289 bhp was MAX.
Forgot to add if it's remapped the torque I believe is altered a lot you lose some grunt higher up.
Others who have had done will know more.
D

That doesn’t make any sense? Horsepower is torque x revs, so to lose grunt higher up = loss of horsepower
Rob

Torque/BHP Drops off in the higher range I was told on a remap. The torque curve is,altered so you get a bit more lower down the rev range but lose some at the top, where the 3.0si normally peaks. No first hand experience only what I have been told. Not a massive difference but noticeable by all accounts.
D

 

[Anonymous]

The car main bus voltage will haze zippo difference on BHP if it varies from around 11v to 15v...

As others pointed out losses in the power train will result in a wheel driven dyno, if set up correctly reporting a 10% to 15% loss in rear wheel bhp over crank reported bhp which the manufacturer states as when he runs it, it’s in a test cell with no air con, alternator or other items dragging the power back, let alone, clutch, gearbox, prop shaft, rear diff and wheels.

261 bhp to 234 bhp is 10.5% so you are perfectly normal...

As others say give the long history of people trying to find a quick fix for instant bhp on this normally aspirated car indicates 20bhp is all you can hope for with a simple remap..

Generally exhaust systems for many years have not been shown to be that restrictive, people confuse noise and vibration from re worked exhausts as speed..aka Yamaha FS1E for those that can remember those with a painful tin can exhaust...

 

[ChrisPDuck]

Spot on pbondar thanks for info after much research today I have found everything you’ve said to be true the S54 engine is the faster n/a engine and after the research on them I’ve found the engine to be set up a lot differently and after thinking of transplant unless you get the engine for nothing and are extremely lucky it would still work out cheaper to buy a Z4M I don’t regret buying my si at all was looking at the VXR and I’m glad I went with BMW Z4 si coupe love the car
Again thanks for the reply and info mate

 

[Anonymous]

I also note that on the runs I have been with a wide variety of Z4s of all types that I can’t easily differentiate which engine is the most powerful as the driver has much greater effect than the engine...