Just wondering how many of you have upgraded the n75 valve to an n75J? Is it worth doing to a standard car, or more worth doing after a remap?
Been covered loads in the past mate.....
Calm down mate, i was hardley being a keyboard warrior!!
I spent about an hour looking through threads about the N75 yesterday and came to the same conclusion that andy has posted above.
and just to add a twist to it:
What would be the difference between a mapped lc with a normal n75, and an lc with an n75j?
it should be instant.
...What is the reason you put the J valve on? - just to get more boost? - if so you can up the boost with an sps controller.
And remember, more boost or higher timing doesnt always mean more power. There are limits and running to high boost or timing that isnt suitable will actually mean less power.
sps controller from revo allows you to adjust the boost levels and timings.
however you will not get to stop the drop off in boost at high revs, as this is simply due to the fact that the turbo cannot hold that amount of boost high up the rev range.
(if you imagine that at 3,000 revs the quantity of air being boosted will be half that at 6,000 revs..)
you could reduce the boost levels which would in turn reduce the drop off... but then you are running lower boost so no doubt will moan its down on power.
At the end of the day running high boost means at the top of the rev range its out of its possible performance limits so you will get a drop off when remapped.
thats interesting.. bcs with the oem N75 valve Id always see 13psi at redline where now with the "H" version Im at 14-15psi at redline... 3rd gear.
im not arguing that the J valve shoud give you higher boost. Its basically delaying the signals it sends to the ecu so im not surprised the J valve sees slightly higher boost.
But presumable you are still getting a drop off from the peak value so it hasnt got rid of the drop off. Although potentially it may be slightly higher up the rev before the drop off.
Higher boost is not always good though