Originally Posted by mcrowley
I agree w/dukted. I ran the oem ic on my 9k for about a year and a half w/stage 4 and I pretty much saw what JZW & others are describing...big spike and it gradually settled down. Last April when I put the big G9/ETS ic in and all the larger piping all that stopped. No more spikes, no taper...it holds steady pretty much all the way up.
Glad to hear the hw will help with boost over-spikes, but from what I can see, the sqr and others, not nordic bring the boost up aggressively and my 9k aero would hit 25psi and fall back to 20psi. With the different boost maping like what Maptun uses, my boost comes up and nails the boost request and does not spike at all, even with stock turbo and ic size.
Part of the issue is definetely how the boost maps are tuned and part appears to be hw. Some people like that boost spike and many people want to feel that surge in torque. If you are one of those guys, you will love a sqr stage 4 tune. The custom stage 4 tune I tried would spike 28-30psi and fall back to 23-24psi on stock tdo4 turbo. It would fall off a good bit in the upper rpm of course.
With my new custom tune it just hits 18psi and holds until after the torque spike and then climbs up to 20-21psi or so and then holds a while and it does hold more boost and power higher into the rpm band, but its all a trade off.
This is more personal preference than anything, what do you want, a nice torque spike or smooth boost that is lower, but will hold higher into the rpm band...
Originally Posted by abdukted1456
the nordic tunes I have had, 02 9-3 SE auto, 99 9-5 lpt, both did not overshoot boost and hold rock steady, unless it it like 95 degrees and then it will pull back some...
but that is why you get a big IC
in fact that is probably a requirement for stage 4+, that is why the tuners probably pull some knock protection, you are supposed to have a very good IC for that stage
I have not seen any nordic tuned files yet, but it sounds like they are mapping the boost by the pid maps more so than the reg kon mats and that is what helps to avoid over-shoots. I did hear of them having trouble figuring out how to use hex file method to look at maptun bin files and they may have learned something from that or just by good ol trial and error and time and testing.
The more tuned files you look at and compare, the more information you h ave and the more information you have, the better the tuning becomes