35is, Aftermarket Turbos

jleckenby

Member
 Leeds, UK
Hey all,

Has anyone fitted aftermarket turbos to their 35is? I'm interested in upgrading mine and hopefully passing the 500bhp mark.

Thanks
James
 
I'd imagine you'd need to upgrade the injectors and maybe the fuel pump to cope with the increased fuel flow needed for 500bhp, it's probably do-able providing the drivetrain can handle the increased power?
 
Tumnus said:
I'd imagine you'd need to upgrade the injectors and maybe the fuel pump to cope with the increased fuel flow needed for 500bhp, it's probably do-able providing the drivetrain can handle the increased power?

Excuse the stab at whp to bhp conversions, just using rough figures!

Injectors are fine until 760bhp (650whp) according to this article: http://www.bimmerboost.com/content.php?7375-VPG-tops-650-whp-on-the-N54-using-the-direct-fuel-injection-system-and-no-supplemental-injection

Other N54 cars will see 600bhp on the stock fuel system. The fuel system on the Z4 is more robust than other N54 cars so I'm not sure how much further you can push it.

See this article for power numbers on 93octane fuel with upgraded turbos, all power figures are quoted in wheel horsepower: http://www.bimmerboost.com/content.php?7423-VTT-N54-GC-cast-stock-location-turbos-93-octane-pump-gas-dyno-results

I'd say 500bhp is easy.
 
I'm surprised the injectors are rated so high, that's a massive overhead over stock power figures!

I did a little more research and it appears the fuel pump may not be up to 500BHP, and the intercooler could probably do with being upgraded.
 
Fuel pump on the Z4 has more headroom than other models.

A lot of people use ethanol blends which have a lower calorific value so the fuel system has to work harder. If he runs normal 93 octane fuel then I think 500bhp will be easy.

This was an old post I remember but they got to 600bhp with 91octane: http://www.e90post.com/forums/showthread.php?t=829687
The LPFP was upgraded but the Z4 LPFP has a much better flow rate than others.

You're right about an intercooler though. Should be the next mod.
 
Cheers for the info guys. I do indeed plan an intercooler upgrade. Toying with either turbos or LSD at the moment. Watch this space!
 
jleckenby said:
Cheers for the info guys. I do indeed plan an intercooler upgrade. Toying with either turbos or LSD at the moment. Watch this space!

LSD no brainer IMO
 
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