Tuning the 3.0si....now as quick as a Z4M

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damocell

Member
 Chorley, Lancs
Thought it worthwhile to document my experience tuning my 3.0si, hopefully to help others who are wondering if it is worth it.

I bought my car in August 2024, completely stock from an engine point of view. I decided to test the 60-100mph time using my Racebox Mini and managed a time of 8.26 seconds, which seems to tally really well with the stock figures I can find online of 8.3 seconds.

Following this, I created my own home-made intake system, fitted an N54 intake manifold and had the car tuned by Bimmworks in the States remotely with an OTS map. The Bimmworks map with its 7600rpm rev limit and N54 Manifold works really well with my 3.73 FD as the car now pulls a lot harder at the top end. Fitting the N54 manifold removes the DISA valves, which helps reliability but doesn't help midrange performance unless you tune the car.

IMG_4410 by Damien Bower, on Flickr

The results has certainly woken the car up. The car feels like it comes on cam at about 5000rpm and really pulls much more strongly to the higher redline. This makes the engine feel more special and more of an event to drive. Peak power is now claimed to be at 7300rpm rather than 6600rpm

Bimmworks claims this gives the car 296bhp. I say claims because I have no proof of this, and probably won't be dyno'ing the car as it's just not accurate enough or worth it due to not having before figures. However, if their claim is to be belived, with my cars weight of 1320kg, my power to weight ratio is not 224 bhp per tonne. Which is up from 201 BHP per tonne.

Interestingly, according to these details I found online, the Z4M has a power-to-weight ratio of 229 BHP per tonne.... although it isn't powered by a V6 ;)
It also states the Z4M covers the 60-100mph dash in 6.8 seconds

IMG_4526 by Damien Bower, on Flickr

Car and Driver tested the Z4M in 2006 and listed it as 1500kg, with a 60-100mph time tested as 7.3 seconds.

Screenshot 2025-11-26 184250 by Damien Bower, on Flickr

Link to data is here: https://www.caranddriver.com/review...2006-bmw-z4-m-coupe-vs-2006-porsche-cayman-s/

So following my mod, I retested my car on the flattest road I could find and managed.....6.97 seconds 60-100mph!!

6ee9ed4e-0778-49b4-879e-4178439e6ba2 by Damien Bower, on Flickr


Not to bad for a FD change and £650 of mods!

Then a Z4M owner mentioned that he'd tested both his 3.0si and Z4M in second gear from tick over to redline in seconds over the 20-90kph metric. This is an interesting one as my mods lose a little midrange power, replacing it with top-end power, so a full sweep of the rev range is great to see. Also it removes traction as an issue and also wind speed.

His 3.0si did it in 5.14 seconds

IMG_4530 by Damien Bower, on Flickr

His Z4M did it 4.4 seconds

IMG_4529 by Damien Bower, on Flickr

So I took mine out, it just scraped past 90 kph as it headbutted the limiter, but it did it in 4.27 seconds

IMG_4532 by Damien Bower, on Flickr

To say I am over the moon with the results is an understatement. The difference is plain to see, and the car feels so much more alive, especially with the raised rev limit and the way it pulls past 5000rpm.

I know quite a few people say it's not worth tuning an NA, but dropping the 06-100mph time so significantly has definitely been worth it for me. The combination of FD swap with breathing mods and higher rev limt to suit has increased performance across the board.
 
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Thanks for sharing, never thought that intake mods and a tune would make that big of a difference.
As a side note, the N54 manifold looks tiny compared to the N52 one!
 
That's a great result. :thumbsup:

I've often wondered what could be achieved if you went to town on an N52 with Schrick cams, ITBs, etc.
 
Micke said:
Thanks for sharing, never thought that intake mods and a tune would make that big of a difference.
As a side note, the N54 manifold looks tiny compared to the N52 one!
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Yes, the N54 manifold is significantly smaller. Gives me more room to fit my hydraulic steering upgrade too
 
Nice one Damo. What’s the point of the N54 intake manifold by the way? Higher air flow?

Always felt the N52 could rev higher. Just gets up there so well.
 
Yeah is the N54 intake still using 3 stage ps with the two DISA valves of the Si cars?
 
Mr_Reeves said:
Nice one Damo. What’s the point of the N54 intake manifold by the way? Higher air flow?

Always felt the N52 could rev higher. Just gets up there so well.
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Cheers bud. Shorter intake and higher flow at higher revs. With the stock intake manifold, it's tough to make power over 6500/6600 rpm. With the N54 it makes more power higher so can benefit from a higher rev limit. One guy in the states has an 8000rpm rev limit, but that just seems high. My peak power is now at 7300 rpm, if I had headers it would make power all the way to 7600 rpm. Although, I've seen some evidence that the N52 valvetrain is very similar to the S55, so 8000rpm could be ok. I just wasn't comfortable going so high.

The downside of the N54 manifold is that you lose a little midrange performance over a mapped stock inlet manifold as it doesn't have the DISA valves, a positive is, it doesn't have the DISA valves :) The map I have should restore the lost midrange performance to stock untuned levels which I was comfortable with.

As my car has a lower FD and I want power at the top end for track it makes sense. Would I recommend it to all users/drivers. Probably not, intake and remap might be the best option in most cases.
 
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James35i said:
Great write-up and results, for £650 it seems like a no-brainer if you have an si!
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It does, and it isn't at the same time. My FD change will make a difference. Especially as it really helps that my car revs out so much quicker and works the top of the rev range more. I don't include that in my cost as it was a free upgrade when I had my LSD built.

It would be very interesting to see the difference my designed intake with BimmWorks software would make to a stock car though. That would be a total cost of c£530, more if the person doesn't own a OBD cable. They claim 285bhp for stage 1 with 245 lbft. So that's 13 less HP than my setup, but interestingly 11 more Lbs-ft, which will help stock FD cars.
 
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