VersaTune User Forum

Guys...

I know it's a difficult question to answer, and being conservative is the best policy. I am after what you feel is the maximum load target for what is essentially a stock car.

Currently, I am targetting maximum of 1.988 via the APP Requested Load Table. I am able to hit 1.97 in the logs.

Ideas.??

I think that only the OEM can answer that definitively. I know one VersaTuner customer who has run upper 2's with a GT35 on a stock bottom end.
Conversely, there are completely stock tuned engines that have bent rods.

2.0 load is only a little more than a 12% increase over stock max load for a CX-7.

I was targeting just below 2 (1.98) and found in the logs, that boost was hitting 17 - 19 PSI, which personally feels a bit too high. So I am going to try a file targeting 1.85 to lower the boost pressure.

Thoughts..??

19psi is still well within the efficiency range of the K04.

Steve @ VersaTune wrote:19psi is still well within the efficiency range of the K04.

Thank you for the reply.

I've always been of the belief that 17+ PSI is a major stress for the turbo (particularly on the CX7), and should be avoided. This is why I created my next version with a lower load target.

Also, I have emailed you the log and the definition for your information. Any ideas would be most helpful. And yes, I did notice the knock..!!

Thank you..!!

Steve the cx-7 turbo is smaller than the ms3/6 turbo, ide put its max around 19psi @ 4000 rpm and tapering to 15-16psi by redline.

I know it's smaller. It will just flow less at that 19 psi than a Speed3/6 K04 will. I doubt the compressor A/R is that radically different.

06Speed6 wrote:Steve the cx-7 turbo is smaller than the ms3/6 turbo, ide put its max around 19psi @ 4000 rpm and tapering to 15-16psi by redline.

I would have put it less. I have seen CX7 logs from the past with tunes that hold about 16PSI, and redline around 12-14PSI.

And yes, this is my understanding also. The turbo and inlet (??) is slightly different than the MS3/6. We have in the past always tried to keep the maximum pressure not much over 16PSI. Stock pressure sits 14-15PSI.

At 150 g/s flow it's probably fine. At 200, not so much. Without a compressor map, it's all speculation though.