27-02-2017, 12:43 PM
Its a well discussed area, with lots of questions, and lots of opinions. And to really explain it from my point of view, would take a long while, which I don't really have right now, but maybe when I do have some more time, I will pick out some example dyno graphs from the many HDI powered cars that I have tested here and show the general results.
The first thing I would say though, is that from my experience, a good 90%, if not more than that, of HDI's that I deal with, or come across, are broken.... Even if everything appears to be good, they make poor power, throw codes, cut out, or run like crap. These early generation CR systems on these 8v HDI's now they all have miles on them cause a huge amount of issues, and its extremely rare that one makes near stock power, even often the case on cars that are apparently "mapped".
Classic issues include, but not limited to bad MAF sensors, bad FPR's, bad HP pumps, knackered injector / injectors, useless air filters fitted badly.... , poor maintenance leading to early valve train issues.. wiring faults in the loom, and the list goes on, Normally cars will start and drive, but give all kinds of issues, and make poor power once you get them loaded up and logging what is REALLY going on...
So normally first mission with any HDI, is just getting them "fixed" before even considering tuning them, people tend to assume getting a new ECU calibration will just fix all the issues and make the car great again, but in reality, it will just make the problems 10x worse. The injection system is fairly limited on these engines to start with, never mind when power output is increase, any knackered / worn components instantly become a serious problem.
From my experience, a "good" or sorted out stock HDI, will make around 84-86hp (Estimated flywheel power measured on a chassis dyno) I have never seen a HDI make book power, ever. With a basic recalibration or "Stage 1 tune" they tend to make around 118-119hp, but as said above, unless the car is actually sorted / working correctly, they will often make alot less, if even stock power!
"Stage 2" power is something that is even more debatable, as so much depends on what has actually been done to the engine, how well the engine has been maintained over the years and lots of other factors. But as a whole, if the car has a stock clutch, stock intake/filter, stock turbo, larger exhaust, FMIC of some form and a MBC fitted to the turbo actuator to allow a manifold pressure increase, they generally make 135-140hp. And again, most will fail to do this without work / new parts. Normally cutting out randomly due to rail pressure dropping to low below request, or loosing power as valves begin to float at the top end from high EMP.
I know endless people have Dyno graphs to prove there car is making x power and x torque, and you can read into this what you want, I also know that if i put my DT on a random dyno, it would probably make 250hp+....So why don't I just go and take my car somewhere to generate such a graph? Because I'm not interested, I could fudge the figures on my own dyno if that was what I wanted to do, but I don't.... I understand how the dyno works, and how it is calibrated, and math doesn't lie. Its a highly debated subject, so can read into it how you like. It can be a bit of a "heart breaker" in alot of cases, but always makes the numbers I am expecting....Just maybe not the numbers the owner is always expecting.
End of the day, the 8v HDI in the 306 is fitted with a 46mm turbo from 19+ years ago.... Do the math, sure your car is making 155-160hp?
Im not having a rant, I, and others I know have learnt alot of the last few years, and the one thing I would say now, is that the internet can sometimes be full of rubbish, and if you want to know something, best thing you can do is go out and try for yourself!!
The first thing I would say though, is that from my experience, a good 90%, if not more than that, of HDI's that I deal with, or come across, are broken.... Even if everything appears to be good, they make poor power, throw codes, cut out, or run like crap. These early generation CR systems on these 8v HDI's now they all have miles on them cause a huge amount of issues, and its extremely rare that one makes near stock power, even often the case on cars that are apparently "mapped".
Classic issues include, but not limited to bad MAF sensors, bad FPR's, bad HP pumps, knackered injector / injectors, useless air filters fitted badly.... , poor maintenance leading to early valve train issues.. wiring faults in the loom, and the list goes on, Normally cars will start and drive, but give all kinds of issues, and make poor power once you get them loaded up and logging what is REALLY going on...
So normally first mission with any HDI, is just getting them "fixed" before even considering tuning them, people tend to assume getting a new ECU calibration will just fix all the issues and make the car great again, but in reality, it will just make the problems 10x worse. The injection system is fairly limited on these engines to start with, never mind when power output is increase, any knackered / worn components instantly become a serious problem.
From my experience, a "good" or sorted out stock HDI, will make around 84-86hp (Estimated flywheel power measured on a chassis dyno) I have never seen a HDI make book power, ever. With a basic recalibration or "Stage 1 tune" they tend to make around 118-119hp, but as said above, unless the car is actually sorted / working correctly, they will often make alot less, if even stock power!
"Stage 2" power is something that is even more debatable, as so much depends on what has actually been done to the engine, how well the engine has been maintained over the years and lots of other factors. But as a whole, if the car has a stock clutch, stock intake/filter, stock turbo, larger exhaust, FMIC of some form and a MBC fitted to the turbo actuator to allow a manifold pressure increase, they generally make 135-140hp. And again, most will fail to do this without work / new parts. Normally cutting out randomly due to rail pressure dropping to low below request, or loosing power as valves begin to float at the top end from high EMP.
I know endless people have Dyno graphs to prove there car is making x power and x torque, and you can read into this what you want, I also know that if i put my DT on a random dyno, it would probably make 250hp+....So why don't I just go and take my car somewhere to generate such a graph? Because I'm not interested, I could fudge the figures on my own dyno if that was what I wanted to do, but I don't.... I understand how the dyno works, and how it is calibrated, and math doesn't lie. Its a highly debated subject, so can read into it how you like. It can be a bit of a "heart breaker" in alot of cases, but always makes the numbers I am expecting....Just maybe not the numbers the owner is always expecting.
End of the day, the 8v HDI in the 306 is fitted with a 46mm turbo from 19+ years ago.... Do the math, sure your car is making 155-160hp?
Im not having a rant, I, and others I know have learnt alot of the last few years, and the one thing I would say now, is that the internet can sometimes be full of rubbish, and if you want to know something, best thing you can do is go out and try for yourself!!
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