Bf Mk2 Valve Float At 14 Psi

[6onb00st]

recently had my car dyno tuned and was told it had valve float at 14psi mods it has are injectors,plazmaman 800hp kit,fuel pump and surgetank,cooler thermostat im running the standard exhaust though could this be the problem cause I thought bf mk2 have the f6 valve springs so should handle the power any advice would be great

cheers matt

[Buf-Phoon]

freeing up the std cat may help relieve some back pressure, which can help alleviate valve float. You are creating a lot of exhaust pressure without giving the gasses an efficient escape.

[6onb00st]

would you recommend a full exhaust system if so what brand and size would you recommend

[Buf-Phoon]

All depends on what power you're chasing. The std system with a free flowing cat ( biggest restriction) can still make very good power.

My exhaust is probably a bit of overkill given the power I make as it is capable of sustaining more power.Which I am not chasing.

Makes 370 rwkw doing it with minimal stress and no plenum @ 15-16 psi

http://www.fordxr6turbo.com/forum/Chasing-1000Hp-t61164.html&st=54 # 64

[6onb00st]

im only chasing about 330 rwkw so would just a high flow cat be enough or should I just go a full exhaust system

Edited 10/12/09 08:36 AM by 6onb00st

[tonyv]

Just get a good hiflowing cat and youl be fine for 330rwkw

[mr gsr]

I have a 10/07 BFII... Was running std crossover, 3.5" exhaust, PW Cooler, F^ airbox, 15psi boost and it was fine (325rwkw). Changed to the process west plenum and 4" intake and immediately had valve spring issues at anything over 12psi and could only muster up around 315rwkw.... Valve springs upgraded and problem solved

Car only had 60,000km on the clock....

Doesnt seem that all BFII's were created equal

[xd turbo]

I am looking at doing the plenum change what is your feedback? is it worth it?

Edited 29/12/09 12:43 PM by Buf-Phoon
quote removed

[mr gsr]

[quote name= turbo' date='29 December 2009 - 09:17 PM' timestamp='1262085437' post='966757]

I am looking at doing the plenum change what is your feedback? is it worth it?

Depends on what you want.. if you want to keep a stealth look, then I would say no....

After the plenum, I got the same power 325rwkw on 12 psi (vs 15psi and the acutator maxed out). The actuator being maxed out was largely due to the stock intake piping with the F6 snorkel. Trouble here was my valve springs wouldnt let me run over 12psi.

There was no loss in the power or torque curve, boost curve was much much smoother, and throttle response was defintely much better, all on 3 psi less. Then when you add a 4" intake on as well, your looking at 50 odd rwkw over the previous setup....

Havent had a chance to go back for a final tune after the valve springs... But I know its now running 15psi instead of the 12psi.. and it moves Will be going back in the new year for a final touch up on the dyno