hi. fairly new here and have some questions on putting a vernier on the exhaust cam.
firstly has anyone done it and noticed the difference in driving??
and would the car need mapping or could i just fit it and drive it??

iv read that you can run -8 degrees is this correct? safe? and will it compromise low down power or just push it higher up the rev band.

thanks in advance if you can help.

 

pretty please

 

dont go making me beg for a reply now..

 

Not got an st170 but have the engine in my mk2 escort. Read a bit about what can be done and its limited what will work without a remap. -6 deg is what most set the exhaust cam at. You'll find more info on American forums look for the focus SVT

 

ok thanks rob. will search the svt forums.

 

I did this to my ST170, i imported a CFM pully amongst other things from the states. I retarded my Timing -8 as i found this at the time to be best for my engine. It equates to exactly half a tooth retarded so...............technically if your confident enough you could time your stadard exhaust cam to be half a tooth out, but i wouldnt reccomend it as -8 is getting close to valve contact.
It will not give you more power but it will move the power band up the rev range. If i did it again i would only go -6 degrees as at -8 it bogged down a bit on launch but as soon as you get up the rev range it would pull and pull and pull. I had a long blast of a few miles with a Merc once on a private track of course and i was pulling away with a GPS indicated 147mph. So it definately helps top end. It just makes the car more lively.
You dont need to map it, set it at -4, go drive it, then at -6, go drive it, then at -8 and see what suits you the best.

 

thanks appreciate advice. i thought you can gain 8 to 10 bhp from doing this?? is this not true then as you say??

 

Its kinda true!?
Basically at the end of your rev range with standard timing, the power stats to fall away towards the red line. If you retard the exhaust cam then the your still making maximum power at the end of the rev range, so you may gain 8-10bhp of your power back.
I had an increased rev limit on mine also so would be pulling the engines maximum power for longer making the car quicker.