SUPERCHARGED NC Racer Project!

TarkMalbot · Post by **TarkMalbot** » Thu Apr 16, 2009 1:05 pm

My 226bhp is with a calculated 20% losses. My rear wheel power was 180.

What A/F should I be looking for? 11:1 12:1 or somewhere in between?

Post by **Brian** » Thu Apr 16, 2009 2:23 pm

TarkMalbot wrote:My 226bhp is with a calculated 20% losses. My rear wheel power was 180.

What A/F should I be looking for? 11:1 12:1 or somewhere in between?

Yes, suggest aiming for 11.8 to 12.2 range....strong but safe. Hard to compare different brands of dynos, different conditions, on different parts of the planet. Thus, chin up about the results...the apparent discrepancy can easily be little to none. The Dyno is a very useful tool for tracking results of your own tuning from start to finish....not nearly so useful in comparing results, especially when brand of dyno and many other variables are in play.

TarkMalbot · Post by **TarkMalbot** » Fri Apr 17, 2009 4:05 am

Thanks for that. One good thing that did come from using two different dynos is that the both measured the power at the wheels to be the same. I am not bothered about power at the engine as these are only calculated or guessed anyway and after all it is the wheels that are touching the ground!

The good news is that when I get the mixture leaned out it should be even faster and I will save fuel!

Sandor · Post by **Sandor** » Fri Apr 17, 2009 7:14 am

Brian,
Is there any speculation on how much boost the NC can handle with out blowing it up? Is it possible to push it to 10 or 12 PSI safely?

sloopercat · Post by **sloopercat** » Fri Apr 17, 2009 7:19 am

Brian wrote:Ahh...the ups and downs of tuning!

That 226 is not bad. I too was back on the dyno this morning...fell down to about 237 hp. I found we had a boost leak. Fixed the boost leak. Problem is, had previously done a full day of dyno tuning on the way to the Laguna event NOT REALIZING we had that boost leak the whole time. So, the tune was optimized for the car WITH BOOST LEAK. The good news is that fixing the leak meant I picked up about half a pound of boost! The bad news is that it also meant my perfect calibration is now too lean. That's a day of work out the window. It also underscores how sensitive the numbers are to being too rich, or too lean. Just a few points off of optimum A/F ratio in either direction and you can be giving up 20 to 30 hp!

Where was that boost leak? It seems like a pretty sealed system.

Post by **Brian** » Fri Apr 17, 2009 8:04 am

Hi Bruce,

Remember I mentioned playing with going back to factory temp sensor. We were in such a rush to get ready for laguna we pulled the temp sensor from the supercharger housing and forgot to plug that sensor back in.

sloopercat · Post by **sloopercat** » Fri Apr 17, 2009 8:10 am

Wow, you would of thought that would whistle like heck. I assumed you would have just pulled the plug off the connector?

Post by **Brian** » Fri Apr 17, 2009 9:49 am

sloopercat wrote:Wow, you would of thought that would whistle like heck. I assumed you would have just pulled the plug off the connector?

We did just pull the plug off the connector...leak was through the connector. Plug back in now. It didn't make any whistle at all...but it did leak pretty good.

TarkMalbot · Post by **TarkMalbot** » Fri Apr 17, 2009 1:51 pm

Any more info for me on the temp sensor? Mine seems to be about 10 degrees Celsius out at 10 degrees ambient temperature.

Post by **Brian** » Fri Apr 17, 2009 4:42 pm

TarkMalbot wrote:Any more info for me on the temp sensor? Mine seems to be about 10 degrees Celsius out at 10 degrees ambient temperature.

None, they didn't see enough reason to proceed further on that.