PourBoi-Jay

Any pics or videos of these pulls for us to drool over?

powdrhound

Thanks! 150hrs is a reasonable target...

powdrhound

We are planning on another dyno session in two weeks. I will get some videos then.

2fcknfst

That is a fantastic looking graph, bravo.

Has the AFR changed with the bigger turbos?

powdrhound

Basically same AFRs. It's all about what you set it at in the tune.

2fcknfst

Sorry, what i meant to ask is, are you running a little richer due to the increased airflow?

s65e90

more air = leaner running

2fcknfst

What i meant to say, x2, the frames on his new turbo are larger than the 980s, so in order to compensate for the increased air flow, is he running the tunning a little richer....

powdrhound

I have not scrutinized the logs but I don't believe so. I think the target is still .78 to .80 lambda at full boost. The ECU adjusts fueling to meet that target. Obviously more airflow = more power = more fuel, all to meet the same air fuel ratio.

2fcknfst

I think it would be neat to see if you are using more, or less fuel than with the 980s - duty cycle, flow, pressure - in theory, you should be able to use the same, or perhaps even less if the turbos are that much more efficient, plus the move from the stock ecu to motec should provide granularity in the timing, spark and fuel that is superior over a 20+ year old oem ecu.

All told, that is a very cool setup John, i hope you kick some serious a$$ next season.

Cheers,

powdrhound

I suspect you are right but a lot of that is above my pay grade. I do know that the XR1000 provide substantially less back pressure than the 980s and are much better at evacuating heat from the engine. The engine really runs cool and I'm looking forward to seeing how this will be reflected in on track oil temps. While on the dyno, we actually had to take the fans off the car in an effort to get the engine hot enough when Chris was setting up the knock sensors. Another indication of the substantially higher flow in the 1000s was the fact that we initially had a bit of a boost creep issue. The 980 with their higher turbine drive pressure did not have this problem. Chris remedied that by machining a longer coupler on the WG rod in order for us to get more opening on the WG itself. On the XR980 we had 13mm of WG travel with 7.5psi cracking pressure but on the 1000s we needed 19mm of travel to open the WG more and are using 4.0psi cracking pressure. Yes, we could have gone with an external WG but the added weight and complexity was simply not an option I wanted to entertain. All in all the 1000s were a bit more tricky to set up but the gains from midrange to top end are impressive. Again, what really makes these turbos shine is the ability to custom map the variocam profile for this application. The more I learn about the M150 ECU and what can be done with the associated tuning software, the more impressed I get. There is simply no way you could extract close to 900 whp on 1.25 bar on a stock ECU.

T10Chris

Hopefully John doesn't mind that I chime in with my experience, I've been playing with standalone ecu on this platform for a few years now (and am following John's footsteps in switching to the Motec M150 - amazing setup). These more efficient turbos/variocam optimization are allowing significant more air at lower boost- so while the boost pressure is lower, the amount of air flowing through the engine would be greater. The efficiency improvements are putting less strain on the setup and generating less excess heat, but more power due to airflow increases always requires more fuel if you want to maintain the same air/fuel ratio so I think it is a safe bet that the engine is consuming greater fuel volume.

There are situations such as adjusting ignition timing or injection timing that can make more power without requiring a fueling increase, but those gains are from changing when the combustion process begins/ends and optimizing how the combustion applies force to the rotating assembly using the existing mixture rather than changing the amount of air moving through the engine (and you can get in situations where you change the timing enough to need more fuel, as counterintuitive as that sounds.... it is a bit of a balancing act and going back and forth to find what works best). I'm pretty confident the majority of these gains are from flowing a lot more air through the engine using more efficient turbochargers combined with using tables in the Motec that the stock ecu is not capable of replicating, with a smaller portion of the gains being from more precise control of fueling/ignition that the Motec provides.

2fcknfst

Thank you Chris for chiming in, I find this type of tuning, at your level, to be absolutely fascinating - the control you can exercise at this level is truly something else.

When I thought about it a bit more, it made sense that by adding more mid and top end power, that would come at the cost of fuel consumption, so it would seem logical if the car was tuned identically as it was with the 980s, it may be more fuel efficient with the 1000s at the same power level, but obviously, 900whp requires more fuel.

This project, and its evolutionary process really piques my curiosity, something i would very much like to do myself one day, perhaps not to the level John is going, but a highly tuned, robust powerplant that is mechanically stronger than the power it provides, appeals to me.

Thank you fornyour insights, I look forward to seeing the 900whp graphs when they are available.

Cheers,

2fcknfst

This level of engineering, fabrication and attention to detail is what we produce in our shop, albeit, not in the automotive world, but immensely satisfying nonetheless.

As I mentioned in the post above, this is something I very much would like to do at some point, but until that time arrives, i will thoroughly enjoy what you guys are doing.

Cheers,

T10Chris

I should clarify I am a completely different Chris than the one that is tuning John's car!!!! Sorry for the mix up there. I tune standalone on my own 996TT (and have set up a couple for friends 996/997TTs) and have been sharing my data and calibrations with John's tuner/builder as needed/requested earlier on in the process while he was making a base map. Chris Cervelli is who John uses, and luckily for me he will be building an engine for me this winter and getting me switched over to Motec from my current system so our data sharing and things we figure out on the platform will go that much further in the future for John's car as well as my own. John has also helped me a ton in acquiring hard to find parts and making connections to make my build a reality.

Generally speaking with regards to if the 1000s were run at the same level as the 980s- there may be little improvements in fuel usage due to thermal efficiency, but I would be surprised if it is a massive change. I would expect there to be some fuel efficiency improvements in partial throttle/low load areas over the old setup given less restriction in the system, but John's car doesn't spend much time in cruising rpm to my knowledge haha