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hi all. after much time iv upped my exhaust to a cat back system consisting of 3in stainless into twin 2.5 inch mufflers with 4 inch tips.
apart from all running and sounding great im just looking for clarification
im hitting 18.5 psi of boost much quicker than i did with the stock exhaust is this because im more freeflow than before or is there something else?
8 degrees outside tonight so that could of contributed as well?
thanks
Probably a combination of both...
When was the last time you looked at logs etc? [emoji14]
the full read out on my computer was a while ago. i only noticed the boost read out when giving it a bit on the way to work tonight. ill take a log on the qway home in the morning and upload it. im not up to speed on most of the readings of the data
Haha, this is almost identical to my problem! I also changed the diameter of my exhaust and added a new bypass valve. I too am finding my spool alot more agressive and is actually overboosting past my target of 21psi. I am putting it down to mainly the huge change in the cold since tuned in summer and possibly slight backpressure change in exhaust. My car is in for dyno tuning tomorrow to get this sorted, so I will ask my tuner and let you know his opinion if interested.
A 20 degree difference with an aggressive tune sitting on MAP sensor limits is probably my downfall. Oh well, putting in bigger MAP sensor and EBCS tommorow in prep for new new turbo in 2 weeks time.
thanks @nas711
Probably the lovely cold weather making things fun :D
Catback alone won't have made any real difference (unless you removed your second cat).
Seems to be consistent with mine to Kiwi. Was 2 degrees today in the valley on my way to work and it drove so nicely, but did jump up in boost very quickly (18psi). Gave it a bit of a squirt in 3rd (probably around 4K rpm) and it sat on 21psi almost instantly and I jumped off it. Cruising round this arvo after work and it jumped only at a max of 20 and it required a bit more of a push. I am 99% certain it is the massive temp drop between tunes that has made it do this, so I am sure this is what you are experiencing. I mean, hell I love the almost instant power that the k04 is bringing, but it makes me drive too cautiously as I am worried about boosting past my target and the k04 going full retard.
The most abuse my car ever gets is on the dyno (which is nothing due to no force applied), so I am not worried on a short term scale, but I would just like my tune the way it was where I could hold the foot down and not worry about hitting 22.5 psi!
should be around 1-2 degrees when driving home tomrrow...i agree it should be fun
Retuned it today on the dyno. They explained that I had cold weather boost creep so my targets needed to be adjusted fairly heavily to cope with extreme weather change. Now WOT gives a max of 19.5 compared to 22.whateverPSI lol. Adjusted the torque to come on a tad later and smoother through the rev range (my old tune was very aggressive down low (basically useable boost came on at about 2.2K and held strong). This is a far safer tune and I recommend you retuning to suit the weather as you may be mechanical boost creeping and end up like mine...Quote:
Originally Posted by kiwi
Or you could load tune rather than boost the which gives more consistent performance across seasons!
Rayd would be able to do that yes?
I'd assume/hope so!Quote:
Originally Posted by kiwi
If you live somewhere that has large temp differences, it's important to have the load tables populated... Or at least have the over run tables populated...
Here in Canberra, I need about 1-1.5psi less boost pressure in winter (4-10C) to hit the same load targets as I do in summer (low-mid 30's)
Am still struggling to get the load compensation tables just right tho...
It has not been bitter cold since my tune so not sure how much boost will fluctuate during hotter or cold. Temp has been here about 15-20 which is the average here for the year (vic). Will be an under 5 degree morning in the next few days, so will report back. All i know is, I was probably pushing the k04 to its absolute balls with my last tune as the difference is very noticeable down low. I never used to have to push it past 3.5-4K as the power kick was enormous (thanks boost creep). Now I am comfortable taking it up to 4-5 to get the same power. Don't really care at the moment as my corky is about to be delivered and I will fit asap and tune for the likes of 320hp.
Yep, Rayd will do either boost or load tuning, just not usually hybrid. Mine is boost based, but he asks me to get hot and cold logs (just waiting for one more freezing morning and I'm done!) to make sure it's stable (no knock etc) at all the Canberra temp ranges.