10-12-2012, 07:08 PM
All I can say is, take ALL advice on the interbobs with a very large helping of salt... The amount of times I've assumed "It won't be that because x on y website says it's good for z" and then to realise infact it's all a pile of shit and they were merely speculating from very limited knowledge and understanding...
IMHO don't get too hung up on worrying whether you're going to affect the drive-ability and keeping things within stock limits... Just because a Diesel is rapidly dropping it's efficiency past 3500rpm, doesn't mean to say it's not good to rev it up to there with injection quantities still high... Every engine has an efficiency band, pushing outside of that for PERFORMANCE I don't think is a bad thing...
![[Image: 381981_573951219289116_1830191951_n.jpg]](http://sphotos-d.ak.fbcdn.net/hphotos-ak-snc7/381981_573951219289116_1830191951_n.jpg)
That above is how graphs SHOULD be looking... None of this power peaking at 3500rpm - that's what gives Diesels their crap reputation for "dying off" and "you're better off changing up a gear"....
Dave just out of interest - are you happy to map in bigger nozzles if you have calibration/flow data for the nozzles? Because as I see things - HDis seem to be in a constant battle between RP vs Durations... Because the nozzles really are so small as stock, the RP is through the ROOF trying to get the durations down, which equals more heat into the Diesel, running the HP pump VERY hard to achieve the pressure required... Bigger nozzles would equal shorter durations, less pressure required to achieve the short duration, therefore less power consumed to pressurize the fuel, therefore less heat in the fuel? VP pumped TDis have been running 220bar injection for years and are happily making 250+hp on simply upgraded nozzles whilst still returning 50+MPG...
But yeah - monitoring is one the most important tools in engine tuning - get a laptop running ELM327 and log your railpressure, get airflow logged... Also Johnny as said on the phone - upgraded air mass meter, then you can monitor your air intake, exhaust gas temp, exhaust pressure... Then you have a GOOD idea of what's going on
IMHO don't get too hung up on worrying whether you're going to affect the drive-ability and keeping things within stock limits... Just because a Diesel is rapidly dropping it's efficiency past 3500rpm, doesn't mean to say it's not good to rev it up to there with injection quantities still high... Every engine has an efficiency band, pushing outside of that for PERFORMANCE I don't think is a bad thing...
That above is how graphs SHOULD be looking... None of this power peaking at 3500rpm - that's what gives Diesels their crap reputation for "dying off" and "you're better off changing up a gear"....
Dave just out of interest - are you happy to map in bigger nozzles if you have calibration/flow data for the nozzles? Because as I see things - HDis seem to be in a constant battle between RP vs Durations... Because the nozzles really are so small as stock, the RP is through the ROOF trying to get the durations down, which equals more heat into the Diesel, running the HP pump VERY hard to achieve the pressure required... Bigger nozzles would equal shorter durations, less pressure required to achieve the short duration, therefore less power consumed to pressurize the fuel, therefore less heat in the fuel? VP pumped TDis have been running 220bar injection for years and are happily making 250+hp on simply upgraded nozzles whilst still returning 50+MPG...
But yeah - monitoring is one the most important tools in engine tuning - get a laptop running ELM327 and log your railpressure, get airflow logged... Also Johnny as said on the phone - upgraded air mass meter, then you can monitor your air intake, exhaust gas temp, exhaust pressure... Then you have a GOOD idea of what's going on
