I didn't know I needed flames out the hood but now I do. Thanks.

 

...say less

 

Car wasn't broken and I had a full week until an actual competitive event. So good time to stick it on a dyno a try to yeet some rods.

First off I want to say tuning the 07K felt much more like tuning a BP then a K. And I appreciated all over what an incredible engine the K was when it came to raw performance and numbers. The K responded better to boost, wanted far more ignition angle, had a far greater effective VVT, and ultimately... yielded a better power curve.

07K: 501whp, 450tq.


Initially I was revving it all the way to 7500... It didn't like it. Power drops off hard after 6500. I lowered the limiter to 7000 for the rest of the dyno session.
Power seems great, right? 500whp/450tq, solid torquey motor! But then I pulled up the peak dyno plots from the K... wow. What a motor. Same dyno 9 months later, same turbo, same fuel. Yeah the 07K has an automatic behind it instead of a manual, but AFAIK the 8HP locks up tight unless commanded otherwise so shouldn't be losing much to the torque converter.
Blue is peak K, red is current 07K.


Wow. K's are monsters. 90ft/lb, 120hp more at 4000RPM, 60hp/80ft/lb more at 6000RPM, and K still keeps going to make peak power at 6300. It's a damn shame they vibrate chassis to pieces and don't hold together all that well with the balance cartridge deleted.

Now, a few caveats. That was a fully built, high compression K with a super short cast turbo manifold. Rods, pistons, 12:1, bigass cams, light valvetrain, balanced, ect. 07K is a 9.5:1 motor, right from the junkyard, and I don't think it's at peak health... cylinders #3 and #5 run about 100* lower EGT temps then the other three. I've not bothered to compression test it. I'm also mildly doubtful of the overall efficiency of the turbo manifold as it has quite a few tight bends and is very much unequal length. A slightly better comparison is stock for stock, although the K was on the smaller G25-660 turbo and Z3 head.

07K comes out mostly on top... I think I did eventually turn the K up more than this, but then sent the motor into meltdown shortly after. Still, the differences in low end torque, where I expected the 07K to really shine, shocked me. K24 peaked at 26-28PSI, 07K choked out around the same point. I shoved 30PSI into it to break that 500whp mark, but it was basically down to gaining 5whp/psi at that point. When I build an 07K, cams or intake porting might be avenues to explore to help extend that powerband and find some more effective RPM.

All three generations together. Built K, stock 07K, stock K.



End of the day... number is lower, yes, but I don't think it's necessarily a "bad" thing, or that the car will be substantially slower because of it. While I dyno queened the K at 600whp, I only put that much power though it in 6th gear. 450-500whp is much more faithful to where it lived at normally. Gears 1-4th are still very much traction limited, not power limited, and with the faster shifts/respool time from the 8HP I think the power will be put to use much more effectively. And of course, the 07K doesn't shake your teeth out, loosen your ball joints, or break turbine housings. Biiiiig ups for that.

If the internet is to be believed, the 07K will live for quite a long time at 500whp. Time will tell.

First hillclimb of the season this weekend in Pineville Kentucky. Hope to run with NASA at CMP the week after. Here's to a season of DIY R8 noises

 

First off, congrats on surviving the dyno sesh and the 500whp

Honestly, I'm really surprised at how aggressively the 07K falls on its face after 6K. Maybe that's more a testament to the K series and not a detriment of the 07. Would more aggressive cams on the 07K allow the VVT to operate in a more effective window up top?

Like you said though, with the 8HP blipping through the gears it probably won't be hard to keep it in the powerband and in boost.

 

Same. I didn't expect it to make power up at 7500/8000 like the K, and honestly I didn't expect same peak power, but how hard it falls off really surprised me. Cams would probably help, as hard as the turbo is pushing it seems like it has to be an airflow limitation. But cams/porting/valves are all $$$ that I don't feel like putting into this current motor. Future things.

 

Two upcoming back to back events? Sounds like you have plenty of time to punch those dyno numbers into @Padlock’s tractive force calculator!

Just spitballing off of your gear ratios, I’d imagine it’ll be easy to keep it between 4k-6k on track. Were you able to feel that fall off at 6k pre-dyno? I’d imagine it’d be really noticeable on the butt-dyno.

Congrats on breaking that 500whp mark… smoothly!

 

Any chance the cam timing was off either physically or in the VVT settings?

If that really is how the stock motor behaves I'm sure someone will have a remedy soon as these motors seem to be gaining popularity quickly.

 

First off... good numbers and nice comparisons!

Secondly... the sharp drop-off at 6k rpm does NOT seem cam related to me, but it does seem valvetrain related. Something serious is causing that drop in VE. My bets are that you are seeing valve float causing cylinder filling to go to hell, power nosediving, and torque falling harder than airflow alone would predict. You're likely making enough exhaust and intake pressure for valve float on either side to be a risk and that turbo shouldn't be running out of breath at only 500hp. That hp curve is probably good for another 40-70hp up top if it didn't fall off a cliff. Looking forward to seeing what you find to resolve it, but in the meantime, best of luck at your event!

 

Loving the youtube video m8. Absolute madman.