Boost late to the party!

[maxim]

I have an RB25 180sx. Engine is stock aside from an fmic. Exhaust is 3" cat back so far. The problem I'm having is power (pull) seems to come on late in the rev range. Full boost is achieved by around 3000rpm however no real 'power' as such until 5000rpm. I was thinking it would be an air leak but then would not be getting full boost at ~3000rpm. Any ideas? Thanks

[Steve]

What boost control are you running, if it is stock it would explain somewhat, as the stock boost control is 2 stage, with a cat back you would be getting around 7psi until 5000rpm (magical figure) then 9 psi from 5000 to redline.

2psi isnt alot, but it can make a noticeable difference.

I have heard you can hotwire the stock boost solenoid so you get the full boost across the rev range, or install a bleed valve. If you want the best in boost control and have the dollars, go for an EBC.

Also, with front mount, its safe to run 12 psi without any problems.

[maxim]

What boost control are you running, if it is stock it would explain somewhat, as the stock boost control is 2 stage, with a cat back you would be getting around 7psi until 5000rpm (magical figure) then 9 psi from 5000 to redline.

2psi isnt alot, but it can make a noticeable difference.

I have heard you can hotwire the stock boost solenoid so you get the full boost across the rev range, or install a bleed valve.  If you want the best in boost control and have the dollars, go for an EBC.

Also, with front mount, its safe to run 12 psi without any problems.

Hey Steve, thank's for the info.

The engine is stock. Had the car built just a couple of weeks ago, so still just running it pretty lady like.

What you say definetley makes sense although going for a spin just now the boost guage still hovers around 7~8psi. The 2psi would be a differnece esp on a relativley high compression engine like the RB25.

I'm planning on waiting a few more weeks then installing an Apexi AVCR boost controller. Seems feature packed! Plus I like the idea of being able to down boost in wet, to stay alive

What kind of mods/power etc have you got your car at?

Thanks again

[Steve]

Mods, heaps. Power, I dont know - havent had it on a dyno since the cams and head gasket went in.

[hippy]

2psi makes heaps of difference esp when u running stock engine