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Pfc D-Jetro Or Not D-Jetro?

Faawks

By Faawks,
in Engines & Forced Induction

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GTSBoy Grand Master

GTSBoy

Posted
Posted

It is not "better" and "more tunable".

Air flow meters measure the load directly. They are therefore actually a better way to measure load. They do have a few problems though, particularly with big turbo cars. These being a few age/reliability/dirtiness issues but mainly reversion from poor turbo intake design/execution. Particularly poor design/execution of the BOV return.

MAP sensors do not measure load directly. You need air temperature and a few other things (including engine speed) to work out what the load is from manifold vacuum. You also need to have a "model" of the engine's volumetric efficiency. In reality no-one has that model so MAP sensored ECUs are tuned using the engine as the model - ie you just add and subtract fuel to get the mixture right. That might sound trivial and normal, but in reality, if you then change something about the engine (say a freer flowing exhaust or something else that affects the VE of the engine) then you actually change the relationship between manifold vacuum and load, and hence the tuning changes. Might not be much, might be bad. This is why famously you couldn't just put bigger cams into many MAP sensored engines without them cracking the shits at you. You can do it with an AFM engine and it will probably still need a tune to get it really nice, but it will still get the fuelling pretty much right without much help.

So the choice between MAP and AFM for PFC tuning on Nissans is really one of taste and capability and what your plans for further mods might entail.

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Faawks Contributor

Faawks

Posted
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Posted

gtr jet what would you suggest?

I'm only going with pfc because they're proven and the price suits me, I'm not willing to go all out on a haltech or anything like that, way too expensive for the power I'm chasing.

That's some good information GTSBoy, I'll keep it in mind, I'm really not sure what direction to take my car yet...

gtr jet Veteran

gtr jet

Posted
Posted

I was going to say a Haltech but they are a little on the pricey side. I run a PFC and it does what I need but if I had the money I'd upgrade.

If money is an issue then just stick with a normal PFC and grab a Z32 AFM.

Blackkers Experienced

Blackkers

Posted
Posted

AFM gives a 0-5v reading to the Ecu based on airflow (duh)

The z32 gives better resolution for higher airflow. The factory r33 Afms hit a 5v wall at around 220rwkw worth of airflow. The z32s go much higher, around 550 crank hp according to nistune

89CAL Grand Master

89CAL

Posted
Posted (edited)

Where did you get the 400rwkw number from?

Is it a track car? because if its mainly street driven, you'd be better off running a little less power to make it more driveable

The D-Jetro makes it easier to setup intake pipes, run no/atmo bov etc. But as GTSBoy has said, the MAP sensor calculates airflow, where as a MAF actually measures airflow.

I'd suggest looking into a Link or Vipec. They will end up costing more then the Power FC but offer far more features and options for tuning. Keep in mind that this will mean you will have to change to MAP sensor (although not that bad, they have an inbuilt MAP sensor to get you started) and its suggested that you install an air temp sensor as well, which means you will need to fit it into the intake manifold or a cooler pipe near the throttle body. These arent major issues but worth noting. There will also be a small amount of wiring involved, but nothing to complicated

EDIT: The adaptronic as mentioned above I have heard some good things about, but having never used one I can't give any more advice then that

Edited by 89CAL
Piggaz Grand Master

Piggaz

Posted
Posted

To put things in perspective.

D Jetro is worth say $1000? What's it gonna cost to pull the intake off, drill cylinder 3 and 4 runners for the MAP sensors positions and put it all back together. Let's call it $3-400.

L Jetro. Cost of ecu itself is $700 second hand. IF you need Nismo AFM's, let's call that $500 second hand or $700 new.

That's $1,400 either way

A Link G4 would be something around the $1,800 zone. No drilling, far more advanced ecu, can support things like ethanol sensors if you need it later on. (Never say never)

All of a sudden the old dinosaur FC isn't such "value for money" anymore.

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Badgaz Experienced

Badgaz

Posted
Posted

the power fc is fine...but the cons with the powerfc is that it doesn't have on board logging....but you have the handy controller which allows making changes without laptop, they are easy for tuners to tune.

...

just think about what your end goal with your car is....what GTSboy said is spot on...the MAFless ecu's take more time to tune properly as you have to do corrections that a MAF system will automatically do for you....

FWIW i started learning with a Powerfc and now i kinda wish i had a Link G4....hindsight is 20/20 if you can be patient and save the money then a link or equivalent that allows retention of MAF would be the way to go IMO.

Faawks Contributor

Faawks

Posted
  • Author
Posted

I didn't realise 400rwkw was a lot, guess they're only 2.5ltrs, I've just come from the world of xr6t's where a reliable 400rwkw is less than 5k away lol.

I still have much to learn about skylines.

I might look into the link g4, ethanol is another thing I've put into the future and being able to run a flex sensor would be good.

Thanks for all the info guys.

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