View Single Post
      10-05-2012, 09:13 AM   #127
Karazy
Go Fast And Take Chances
Karazy's Avatar
United_States
50
Rep
261
Posts

Drives: 2020 M2C
Join Date: Apr 2012
Location: Coeur d' Alene, Idaho

iTrader: (0)

Quote:
Originally Posted by NISFAN View Post
I agree 100% with swamp2's logic.

So far we know that current N55HP produces 330lb.ft from a low1200rpm-5000rpm. This is from a single turbo, clearly aimed at producing good low speed numbers.

The fact that it produces the same torque all the way from 1200-5000rpm indicates it is torque limited. (Engine torque restricted by ECU program, not by hardware). If this restricted running mode were removed you could expect a significant increase in peak torque. Maybe 360+ft.lb???? not far off the 395 stated for M3 (albeit at lower revs), and that is with a single turbo size matched for low speed performance, plus camshafts suited for low engine speed performance.

Rev limit on standard N55HP is 7000rpm - Indicates that basic engine is capable of withstanding these forces. Throw in full counter balance crank, forged conrods and lightweight pistons (Upgrades you would expect from M Power) and it is very easy to see an engine capable of at least 7,500rpm redline, plus a usable 7000rpm peak. M engine producing peak power at 5,500rpm??? Yeah right!

Lastly, the N20 4 cylinder engine is effectively an N55 with 2 cylinders less (1/3 displacement less). It is quoted at producing 245hp which, add the two cylinders to make up a 3.0litre I6 is 330hp (similar to N55HP's 315hp). However the true output is said to be higher than the rated 245, some suggest in the region of 260hp, which would be more like 347hp in 3.0litre format.

Anybody suggesting that the M Power team are only going to squeeze an extra 70hp out of an engine set up to produce good low rpm figures? Only 12hp per cylinder? ...........That's NUTS!!!!!

On a turbo charged engine, just changing the N55 turbo to a larger unit and sticking with the same boost pressure would gain this amount with no other mods.

M3 is going to have at least 2 turbo's which gives a clue that the turbo won't restrict power as much as N55.
No doubt more aggressive cams in M3 to lift power peak. All of these point to significantly higher than 420hp.

As for the info released being correct?.......OEM's 'leak' whatever info they want the public to hear prior to launch.

I want to thank swamp2 for a very informative post.....and offer a public apology to him for coming to the wrong conclusion about his engine knowledge. SORRY dude
Even a simple Stage 2 Dinan tune produces 401 lb-ft in a N55
http://www.dinancars.com/shop/D900-3...55.aspx#page=1

Works GREAT for AutoCross
__________________
2014 Corvette Z51 Stingray 3LT, 7 M/T
2015 KTM 1290 SA
Retired- 11 BMW 335, 07 BMW R1200GSA, 04 BMW Z4, 01 BMW K1200RS, 00 BMW R1150GS
Appreciate 0