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Hi guys so ive been running rough recently when i just got my car out the shop with the new RB25DET Neo motor in it and have found out that it could be because i was using a DE ECU instead of a DET one so im hoping to find out if i can still have a front facing plenum on the engine with a factory DET ecu or will that require an aftermarket ecu that needs to be tuned to suit? 

 

Any advice would be great! Cheers

11 minutes ago, zJosho said:

it could be because i was using a DE ECU instead of a DET one

Yeah, no surprise there. The chances of getting the fuelling right with a DE ECU trying to run turbo injectors with boost are slim to none. The chances of the timing advance being right (ie, not way the hell too much) are even lower. You will be lucky not to have damaged the engine if you have managed to put it under any serious load.

12 minutes ago, zJosho said:

can still have a front facing plenum on the engine with a factory DET ecu

Yes, but.....

12 minutes ago, zJosho said:

will that require an aftermarket ecu that needs to be tuned to suit?

You really shouldn't try to run the factory ECU without any mods to it at all - even if you didn't have an FFP. By this I mean that the only sensible way to run a standard ECU is with a Nistune put into it, so you can tune it, to get the best out of it. And if you have something unnecessary, like an FFP, then it would be almost mandatory to be able to tune it, because the FFP will definitely interfere with the air distribution (compared to the stock plenum) and you'd want to be able to deal with that.

But, most importantly, if you do want to use a factory ECU, then you're going to need to use the factory throttlebody, because the factory ECU won't be happy with anything else. And this brings in another problem. Unless the ECU and TB are from a Stagea, then there is a bloody great big traction control auxiliary throttle in the TB. This does not fit well in front of an FFP, and you can't easily hack it off. Well, you can hack it off, but then you also need to go down the path of dealing with the DTC codes in the ECU (only possible with Nistune, by the way) and so on and so forth. Not impossible, but stuff that must be dealt with.

If you must have an FFP, life will be easier with a Haltech and a modern e-throttle, so you can abandon the IACV and keep everything compact.

If you like no low/mid range torque go for it
Biggest waste of money and performance especially all the fake/copy stuff.

This is the only aftermarket plenum to run
https://plazmaman.com/product/rb25-det-r33-skyline-inlet-plenum/

Add DBW and an aftermarket ecu makes it great for drivability and torque everywhere. Can control air velocity by open/close TB at certain rpm/load 

*** I previously ran a genuine greddy & q45 TB best thing I did was go plazmaman plenum & DBW***

 

  • Like 1

Wasn’t there just a Motive video where it demonstrated that shorter runners means a higher turbo threshold? I would not make any change that reduces the length of the intake runners. Personally I’m curious to know how the Plazmaman upper plenum intake compares with the Rajab take on the design which reduces plenum volume but increases runner length. 

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