Z32 power loss upper end

[Gerry car guy]

1990 Z32, i seem to have a power loss above 5000RPM, the engine struggles even in 3rd gear to reach redline, does not rev freely. New plugs, air filter, fuel filter, new Labaree exhaust cat back, nothing seems to really make a big difference. Perhaps I am expecting too much

I am new to this car but have a '90 Porsche that has 240HP and it revs freely.

Any help would be great.
Thanks, G

[NolimitZ32]

Seeing as how you have a porsche I would venture a guess that you are expecting too much because the VG30DE's torque peak is around 4500RPM and boxers are much more rev-happy engines than traditional 60* Vs. Too be sure check your base timing and pull codes off the ecu, also check out the FSM for nvcs testing procedures to make sure the variable valve timing isn't messing up.

[Gerry car guy]

Thanks, the base timing is good and stable, no ecu codes, I had another ECU and no noticable difference. It pulls good till mid 4k and seems to fall flat after that.

I had wondered about the VVT cause it feels retarded, my 02 M3 you can feel the VVT moving around.

How do I ckect the VVT on the Z32na.
Thanks, G

[Gerry car guy]

Thanks, the base timing is good and stable, no ecu codes, I had another ECU and no noticable difference. It pulls good till mid 4k and seems to fall flat after that.

I had wondered about the VVT cause it feels retarded, my 02 M3 you can feel the VVT moving around.

How do I ckect the VVT on the Z32na.
Thanks, G

[NolimitZ32]

Not sure how to check it, never had to deal with it before, check the FSM, there's a link to it in the "everything you need to know" sticky

[Gerry car guy]

Thanks Sticky,
I am new to the board, what does FSM mean
Thanks, G

[marty1mc]

FSM = Factory Service Manual. http://www.300zx.co.uk/cgi-bin/manual.cgi

VVT actually affects the low end, not the high end. It advances the timing so the engine makes more torque. I think the cutover is around 3k rpm. Have you checked fuel pressure and ohm'd out your injectors?

[NolimitZ32]

^this, and yet if the nvcs is malfunctioning it could be causing problems with timing leading to loss of power at any RPM.

[nissanfreak12]

How are the cats? If they are clogged, this will effect the high rpm range. What Marty said about the fuel pressure is also a very good thing check.

[Ace2cool]

That was my thoughts as well. On long drives, does your transmission tunnel heat up? That could be a sign of clogged cats.

[Gerry car guy]

No the tunnel stays cool. I will check fuel pressure it doesnt seem to matter which gear its in