Tuning advice for 3.0si

[Pontio]

Hi every1, this is the first topis im starting rather then just replying to others, hope you can help me out. I am the proud new owner of a 2006 Z4 coupe 3.0si and would like to get it upto or at least closer to the 300bhp mark. it is the N52 engine so already has 260-265bhp depending on what sire you look at. I dont want to touch the exhaust as i dont want it too noisy or obvious its been "played" with. Spoken to a few different companies and there all fairly confident in getting between 15 to 20bhp out of it. However that still leaves me a bit short of 300ish. I was looking at the simota carbon cai's which can give upto 10bhp apparently however they are only for the M54 3.0. Any ideas where i can get a decent cai or anything suttle for a bit of help to get closer to 300BHP? I'm in the uk btw so delivery charges might be silly from abroad.
Thanks for any help

 

[Wondermike]

If you want some more grunt, rather than tuning the engine, the best mod would be to change the rear differential for a 2.5 auto or 2.5Si auto, which will give you loads more torque at the wheels, at the expense of a reduced top speed.

 

[Pontio]

Mine is already a auto.. I'm so lazy.. Would it still be possible?

 

[Wondermike]

Ah in that case not worth it. The std 3.0Si Auto final drive ratio is 3.64 and the 2.5Si Auto is 3.73 so nothing much to be gained there. The manual 3.0 Si is 3.23 which would have made a fair difference.

Back to the drawing board. Remember BMW only get this engine up to 306bhp after adding two blowers (335i) so I think you'll struggle to get close to 300 without doing the same.

 

[plowy]

Mike, is there anyone on the forum who has swapped the diff your mentioning

 

[Wondermike]

Mike, is there anyone on the forum who has swapped the diff your mentioning

Sorry never noticed this, there was someone on Z4um who did it, not in UK, not sure if there is anyone here that has done it. It's the best mod for more performance without a doubt, and if I'd kept mine I would have done it for sure. IIRC the diff is about £1200 plus fitting it, unless you could do it yourself? Get the part no off realoem.com and ring your local dealer.

The older 3.0 like yours is a 3.08 diff so swapping it for a 3.73 would be an awesome change (20+% power/torque increase at wheels), who cares about running higher RPMs or reduced top speed.

:driving:

 

[Caddyshk]

Hi every1, this is the first topis im starting rather then just replying to others, hope you can help me out. I am the proud new owner of a 2006 Z4 coupe 3.0si and would like to get it upto or at least closer to the 300bhp mark. it is the N52 engine so already has 260-265bhp depending on what sire you look at. I dont want to touch the exhaust as i dont want it too noisy or obvious its been "played" with. Spoken to a few different companies and there all fairly confident in getting between 15 to 20bhp out of it. However that still leaves me a bit short of 300ish. I was looking at the simota carbon cai's which can give upto 10bhp apparently however they are only for the M54 3.0. Any ideas where i can get a decent cai or anything suttle for a bit of help to get closer to 300BHP? I'm in the uk btw so delivery charges might be silly from abroad.
Thanks for any help

Should have kicked in for the M. If you want a faster car - buy a faster car - I speak from experience $$$. Failing that advice, SC Kit will get you what you want as far as HP and TQ (for about what the M would have cost you) - of course you'll still need brakes, suspension, bling etc.

 

[Pontio]

I wasnt looking out for a z4 but as this come along an it looked great and i got it at an absolute bargain i could't resist. Doesn't matter, I'll just have to chip it an leave it at that.

 

[Caddyshk]

I wasnt looking out for a z4 but as this come along an it looked great and i got it at an absolute bargain i could't resist. Doesn't matter, I'll just have to chip it an leave it at that.

In my experience $$$$, there's not much you can do for power gains in these modern straight six's with software and intake/exhaust modifications. Your particular setup is tweaked to just about the max without moving to forced induction. You may find 5-10hp max with bolt-on mods and software.

 

[Pontio]

i'v been told by most mapping companies between 15-20bhp and they all sound confident its been done before so i might just do that. removed the resonator spounges yesterday, its so loud now.. dunno if its too loud tho..

 

[Caddyshk]

i'v been told by most mapping companies between 15-20bhp and they all sound confident its been done before so i might just do that. removed the resonator spounges yesterday, its so loud now.. dunno if its too loud tho..

Find someone that's done before and after Dyno's vs the claims.

 

[Z4coupe]

Ah in that case not worth it. The std 3.0Si Auto final drive ratio is 3.64 and the 2.5Si Auto is 3.73 so nothing much to be gained there. The manual 3.0 Si is 3.23 which would have made a fair difference.

Back to the drawing board. Remember BMW only get this engine up to 306bhp after adding two blowers (335i) so I think you'll struggle to get close to 300 without doing the same.

Std SI manual diff is 3.46 auto SI is 3.64. Dont know about about the 2.5 diff. The Bmw twin turbo motor has a lower compression then the SIs, and the 335 is heavier by about 500lbs. The 335 is a low boosted motor. Im sure the motor unboosted is around 225 hp or less. The Si has alot of technological advances which Im not sure the 335 employs such as double vanos, a mag block all which put the Si at a a hp to weight advantage over a 335.

Now the EUR version of the SI is rated at 265 the US at 255, Why I dont know Ive heard that its all in the exhaust manifolds. Anywho. With whats available in the aftermarket now, i dont think 300hp is possible, but you could get close. Here is whats available now or soon:

Supersprint Exhaust
Dinan Software( summer)
Dinan Throttle body
RPI ram air
K&N
3.64 diff( for manual)Turner Motorsports


Its not much but its something, maybe if their were a intake manifold and cam package available 300hp would be a realistic expectation.

Once the tuning code is broken then Im sure having custom cams ground and having either the head shaved(bump compression) and maybe extrude hone the head it would be something to explore. Usually when your waiting on others(aftermarket) to satify you, youll be waiting a long time.

A shot in the dark is a supercharger kit. I dont know why the 05's have a kit for the 3.0 but not the SI, only being the software being the difference in holding it back. Even the M has a kit for it. With a supercharger you looking at over 300hp easily, more towards the 350-400hp mark.

I still think the SI is underated by BMW anyway, in terms of power. 0-60s and 1/4 mile mph and times, plus numerous dynos confirm this to be true. I feel the SI BHP is closer to 275-280 crank hp to be honest.

 

[Cyscrofer]

Hi there,

can you advise a newbie to the Z4.
I too want to tune the car up a touch, already ripped off the rear exhaust section and fitted quads with sports silencers.
Sound great - loud enought to hear it when you boot it but silent when ticking over or crusing.
If its any use POWERFLOW in Doncaster did the conversion and wow what a job, well recommend it to one and all.
Cost around £500 to do but well worth it, the engine feels crisper and more responsive.
Any way plan on putting a K&N in the air box too to help make her breath better.

Found on ebay dare I say it a plastic box with a PIC chip in it which as you guys state guaranteed performance fuel savings and all that rubbish - but is it worth it?
For £7.95 +PP I wondered if any one else had tried it.
The seller goes on a bout a 1pence resistor sound like a typical cheap treat to fool the ECU to give bigger injector times....?

Anyway since you guys seem to have the finger on the pulse can you advise the best route please?

Cysty :driving:

 

[Dubbedown]

You're never going to extract that much power out of this motor. If you're focusing on 0-60, straight line, drag, etc... best modification would be limited slip + lower gearing. The torque multipler effect + putting power down will help with your 0-60 times. Only other mod that would really contribute to increased power would be headers + tune, and even that will put you short of your goal. Don't bother with a cai, the stock design is efficient as is... aftermarkets will make more noise and suck more hot air.

I love my n52 coupe, so don't get me wrong but if 300hp is a hard target, your better off trading for a m coupe. You'll spend less and have something that fast out of the box.

 

[richtea78]

Seriously, if a £7.99 box would make any difference to an engine dont you think BMW would do it anyway?

Really, how gullible are some people? If it did work it would cost a lot more than £8!

 

[Daffy]

Back to the drawing board. Remember BMW only get this engine up to 306bhp after adding two blowers (335i) so I think you'll struggle to get close to 300 without doing the same.

Not the case. The N54 twin turbo in the 335 is based on the M54 in the E46/Z4 Pre-LCI so BMW have (conservatively) gained 65bhp through the addition of 2 teeny turbos. reports of stock cars generating 350bhp are common though.

I don't think much extra can be had from the N52 engine, hence why BMW themselves have only had single digit gains since its introduction in 2006.

 

[Wondermike]

Daffy, you're right, N54 based on the M54. This thread is four years old

 

[Daffy]

Wow, apologies fella, never noticed the date.

 

[Wondermike]

No need to apologise

I just thought it was an awesome thread revival when I looked at the dates :rofl:

I never bothered much with the twin turbo engine until the E89 was fitted with it. In some respects it would have been an awesome engine in the E85 though.