BMW N54 335i AT Speedtech 1025PS/1011HP-1225Nm/903.5ftlb

135boost

Corporal
Oct 28, 2017
220
1
115
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135is
That is absolut right that different inertia dynos sounds very different cause of roller mass etc so it's not best way to evaluate these whp values.

Right way for sure is to compare it to possible bmep, with stock head and valvetrain this engine is at prox 13 at torque max and prox 11 at 6000 rpm and way under 10 at 7000 as naturally aspired one, assume it's on level of 9.

With good size turbo that 6000rpm could be riced to 12 and 7000rpm to 11, i thimk that's close to max.

Then boost it, 14,7 psi double that, 29,4 triple that and 45psi quadruple that.
Calculate then performance drop of 1%of every 3degree celcius iat over 20c.

Now you are in right ballpark as max what can be reached, e85 increase that by amount, most as iat temp drop and withstand timing pulls but throw there some 5% adding to these values and there you are.

Bmep @ max power 11, boost 30psi, iat 50c and e85 as fuel equal 11x3x0.9x1.05 is 32bmep without any timing pulls.

About 13 bmep equal as calculation to very very close value 100nm/liter and 11 bmep equal to 85nm/liter.

There you have real values to compare, at 50c iat you should hit 850nm and at 30c some 920nm with stock head and 30psi boost.

At 7140rpm with hp and nm it's like footpound and hp at 5252.

Stock head , assume optimistic 10 bmep at 7120, you should hit some 700hp at crankshaft.

That 5000rpm plus is the place where ported head and cams start to shine, there is possible to reach some 12-12.5 bmep at 7140rpm and that turn tables fron 700 crank to 840-875hp.

These values should be quite max to reach, with small variances.

To draw extreme limits to these hp levels, with formula1 world tech, bore/stroke ratios 1000hp at crank is about all what can be archieved there and these n54 does not come even close to that so don't expect 1000 crank hp to be archieved with anything less than fully built, ported and cammed n54 at rpm levels 7400 and some 34-35 psi.
 
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Zelderlee

New Member
Nov 26, 2021
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Did some selfmade upgrades. works since 2 years.
Definitely some solid upgrades could I do the same with an xi transmission I've seen people talk about it but haven't seen anything for the xi AT I just figured they were the same except the part where it bolts to the t case? But any info would be appreciated thanks again.
 

nyt

Sergeant
Sep 15, 2019
328
1
283
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2010 335xi
Definitely some solid upgrades could I do the same with an xi transmission I've seen people talk about it but haven't seen anything for the xi AT I just figured they were the same except the part where it bolts to the t case? But any info would be appreciated thanks again.

They're the same. I've built one, documented thoroughly in my build thread. The 6hp28x is the better way to go. That kit should be ready soon.
 
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Zelderlee

New Member
Nov 26, 2021
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They're the same. I've built one, documented thoroughly in my build thread. The 6hp28x is the better way to go. That kit should be ready soon.
Oh sweet thanks so much as for the front diff and t-case now lol
 

RuskiRacer

Captain
Jul 17, 2019
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2009 e93 335i
They're the same. I've built one, documented thoroughly in my build thread. The 6hp28x is the better way to go. That kit should be ready soon.
6hp28 kit is ready to go im installing the fist one into a 535xi
 
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