Thanks @NowForThe5th. Very informative and has raised more questions for me actually
NowForThe5th wrote:In the Pajero, with the variable vane turbo, similar to the MN, I'm currently running Tune 8 and 23psi boost. Still a touch too rich but boost is controlled by a Dawes valve and holds steady as a maximum, regardless of other conditions. On paper that gives me over 220kW (yes killer wasps, not ponies) and around 700Nm. 0-100 in 7.0 seconds flat. I was running around 28psi but backed it off on advice from my tuner. He's repeated that advice a few times here on the forum, specifically for the 4D56T which is nowhere near as strong as the 4M41.
What was the rough "limit" that was advised for what I assume to be the oem VT16? I've seen countless historical threads on here where a majority were on around the 26psi range for everyday use, and 30psi for short bursts.. some with dual dawes setups. I expect the uprated CCT turbo could easily handle the 26pi constant. Or was the issue advised by the tuner more to do with overall cylinder pressures given the pitted block issue looming? I know there wasn't a real "fix" by MML/MMAL regarding the block, but given my new engine is only 50,000km/2yrs old, im expecting that issue to not arise again so soon if at all.
NowForThe5th wrote:The other thing that you seem to have ignored is the exhaust. 3" exhausts on MNs are an invitation for overboost limp modes. Time and time again it's been said. Even on the 4M41 the standard 65mm exhaust is plenty and although much less common, overboost can happen on those with a bigger exhaust.
Totally aware of the issue, and needed the 3in because I want to constantly run higher than standard boost especially with uprated turbo, which chiptuning Rob advised yesterday is necessary for Tune 9 and up. The overboost limp and the reason it happens for eveyone else isn't my concern at all. I was happy with 26psi on the Tillix setup, but given the the uprated boost range, it was very possible to trigger the overboost limp a lot easier on partial throttles (including whilst on cruise control) exceeding what I assume to be a ~20psi ecu target boost cap. I was, however, not using the separate needle valve to bleed for ramping so could have potentially mostly eliminated that. I know how to feather the throttle and do it even now out of habit, but my wife being my wife, refuses to remember it, and as such, is dangerous for her surrounded by trucks going up the country mountains to visit her parents with the kids.
In a nutshell, I just want to be able to run the higher boost, just as I would on a turbo petrol, without having this limp happen. I'd be happy with the MIL showing as long as it doesnt limp!
NowForThe5th wrote:The Dawes, or Tillix, valves are a nice safe way of increasing boost but your chip should not be relaying a value within 1psi of actual to the ECU. Have you checked the sensor, connections and the signal to and from the chip? If that part of your chip is misbehaving then that could contribute to your problems.
Would like more clarification on "chip should not be relaying a value within 1psi of actual to the ECU". If the ECU is capping the VGT to 20psi based on what I assume to be readings from both the MAP and MAF, how is a chip able to increase the boost well beyond 1psi of the target boost? I assumed the MAP sensor intercept plug was clamping MAP sensor voltage so that the VGT bleed is delayed, and thus, also assumed this would prevent the overboost limp from triggering because the MAP sensor would not have recognised the intercept. Chiptuning Rob said yesterday that the chip doesnt do any clamping, but "reduces the number by something like 10%", and I don't event know what "number" is referring to.
If I was to look at the above explanation another way, I suspect the rail/injector tuning is meant to overboost the normal way just by free-flow and fuelling, and the MAP intercept simply reads the overboosted values and detunes the fuelling to bring the boost back down organically before the 8second P1298 overboost trigger.
Thus if the above is correct, and I am only momentarily seeing a spike to 22psi, the actuator rod limiter on my new CCT turbo may have already been mechanically calibrated for 20psi which could be my issue. Though when I had an ecu remap shortly after engine replacement 2yrs ago, tuner set target boost to 25psi, and it only worked for a momentary spike and capped back down to 20psi. There were countless other threads here where many suspected the dealer will have also updated the firmware with some forms of detuning so could also be this.
If all the above is correct, then how have others had their tuner "tune/remap the ecu for 30psi" and still have the P1298 DTC as a looming factor? And the only thing I can think of is to delete the DTC itself like you would with the EGR for ecu EGR delete. But not a single thread on triton/challenger forum or facebook group details what the tuner has done to achieve this.
As far as I'm aware there were only a very few copies of the software needed to program these chips. Chip Tuning may have a copy but I suspect not. One copy was on a USB which was fried by static. That was the second last one and was going to be installed for use in programming my car.
The last remaining copy is held by a guy who steadfastly refuses to either copy it or even lend it.
This I find concerning. How Is the product then advertised as tunable, and the chiptuning site having a map of authorised tuners for the device? I'm not sure if it was this group or one of the Navarra ones, from vague memory, there is an individual named "Sam" that someone was able to chat with, who made adjustments to tune files and sends them back based on some sensor data a person a had to logue (ie via Torque logging).
Is this the same person you are referring to? If not, then it may have been another car forum and I will try seek them out for a copy. Does chiptuning and their authorised dealers not have a copy of the software?
NowForThe5th wrote:I do have a whole bunch of tunes, a couple of them customised for my Pajero and some also customised for various MN owners. No way of telling which is which, though, without the software. Although the performance is mind boggling, I've stayed away from the 10-15 tunes after blowing a hole in the side of the common rail once and totally destroying a solid copper disc gasket on the brick in the end of the rail, a couple of times. Messy but not as expensive as a new common rail.
I recall in the tillix thread you mentioned that bursting had happened to your rail, but good to know now the exact reason that it was because of the Dom and Tune10-15. I mite even go back down to 7 or 8... I've alreayd had the limiter leak, and the main pump?rail pipe in the middle of the rail burst through a hairline crack at the tip of the end on the rail side.