Quote:
Originally Posted by SeanWRT
You mentioned your possible next step is the WMI. Think twice.
If it's the more power you're seeking, the upgrade to STG2 turbo is the way to go. With WMI, the stg1 turbo becomes the bottle neck. You flow more cooler air but turbo works harder and thus hotter. Instead, STG2 turbo with WMI makes up to 500whp, no fueling, no ethanol, nothing needed. Much more powerful AND reliable than STG1 Turbo+WMI+Ethanol. With stg2, you can step back a little (450-470) and get even more consistent power.
If you use WMI for IAT cooling, it's not even necessary in your case where Ethanol or race gas have taken good care of the timing already under the IAT you're running. In addition, your oil and coolant are rock solid. True, IAT is limiting the HFM but again, for power, go back to above turbo discussion.
I've never seen any track car that relies on aftermarket WMI in the long run. Reliability is a big issue. No mention all the maintenance, and proper tuning required for it to maximize its use.
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Thanks
SeanWRT
You're right that I need to think about this twice, thrice, and another time before deciding my next step. I accomplished my goal for this year, so I have some time to contemplate before acting.
There's a bit more to this than wanting more power, so I'll expand:
IATs:
I drive the car hard enough on track that regardless of ambient, I'll likely always see IATs 50-60F higher. Because of that, I'll likely continue to run E30 (except for in the winter) to keep consistent power levels as IATs get high.
The only thing that comes to mind to drop IATs is water/meth injection. If I drop them enough, I can skip the E30.
Power/Turbo:
It would be nice to get 450+whp, but the potential drawbacks if I don't do it right are more turbo lag around town, and more heat. I understand that as power levels increase the larger turbos run cooler, but I will use every bit of additional power to the maximum on track and I inevitably will end up back to IATs being 50-60F higher than ambient, albeit with extra power.
Another drawback that I would need to be prepared to deal with is more power = more speed = more brakes = more suspension. I have Dinan HAS and front AP BBK, but I'd likely need to upgrade suspension and braking further to manage the additional speed on track. Not a bad problem to have, just a note that costs increase elsewhere on the car, as well.
Fueling:
Running E30 is definitely a balancing act. At the track, it's easy (minus having to transport and measure E85) b/c IATs are high enough that full boost/power potential isn't hit, so the HPFP never crashes.
Altho, on my 1100mi round trip drive to the track, temps dropped to 65F at one point and I had to drop my E mix to E23 to not get any drop out when simply giving the car more throttle to pass people on the interstate. My background is Chemical Engineering, so I don't really mind playing and experimenting with different fuel mixes, but it can get a bit annoying when the HPFP crashes.
If I want to run a higher E mix or run E30 in cooler temps, an XDi pump is likely needed. My gut tells me the B58 pump wouldn't be enough, but may be worth an experiment sometime.
If set up correctly, water/meth injection should remove the need to run E30 and could provide a little additional fueling if the HPFP if its on the edge of cutting out with a bigger turbo & tune.
Cooling:
This is actually my biggest issue and what needs to be addressed before anything else. What the logs don't make clear is that the M2 pulls power and short shifts when coolant is >242F and oil is >273ish F.
While the E30 was keeping power levels up while IATs were high, I was hitting coolant temps >242F pretty easily and running them up to 256F (the car goes limp mode at 260F), which is not good! The car pulling power and short shifting was slowing me down a couple seconds a lap as the engine got hotter.
I'm not really sure which direction to go with additional cooling, as the only fixes I know of have significant compromises for a daily driver that is driven hard on the track: CSF race radiator requires AC delete, getting more airflow into the nose kills the OG M2's good looks, and splitting the oil/coolant exchanger means oil heats up less quickly in winter time. I really don't want to make any of those changes.
My thought on WMI is that it would indirectly buy me more time before engine temps get up that high, by helping to keep IATs lower. Altho, I have no data from anyone in my situation to confirm that. It would just be a hope and a wish.
Overall:
Because of the improvement to IATs that WMI would provide, along with potential small gains in power, fueling, and engine temps, it made sense to me that it's the next step.
Personally, I'd rather put on a bigger turbo and tune if it addressed all the above, but I'm not sure it does in my case. Basically, I'm at a coin flip right now, and any input is appreciated!