jp4 lumps

  1. Established Member Joined: Nov 2008 welwyn garden city, hertfordshire Posts: 2313 s1 106 xsi
    #1
    im looking at getting a 307 jp4 lump but they only have 110bhp thats 10 short of what the j4 lump

    whats the difference between the 307 jp4 (c2 vtr) and the c2 vts lump for there to be 15bhp difference?

    cheers for any help in advance
  2. Saxperience Forum Bum Joined: Nov 2007 Leeds Posts: 2865 172 Cup, Mk2 VTR
    #2
    c2 vts lump is T5JP4S code. differences being metal inlet, racier cams & pocketed pistons iirc.
  3. Established Member Joined: Nov 2008 welwyn garden city, hertfordshire Posts: 2313 s1 106 xsi
    #3
    Is the jp4 not the jp4s the lump that people put the j4 cams, springs and retainers in to get around 130bhp?
  4. Saxperience Forum Bum Joined: Nov 2007 Leeds Posts: 2865 172 Cup, Mk2 VTR
    #4
    Quote:
    Originally Posted by shaneio View Post
    Is the jp4 not the jp4s the lump that people put the j4 cams, springs and retainers in to get around 130bhp?
    jp4 is the c2 vtr/307 etc engine. jp4s is the c2 vts engine.

    people use the jp4 head (any of them) on the j4 block for the bigger inlet valves compared to the j4 head, and use hte j4 cams springs and retainers for better oomph
    1 user thanked this post:
  5. Saxperience Forum Bum Joined: Dec 2008 Lancs Posts: 4124 JP4S'd R.
    #5
    Just fit the whole engine, lower miles.

    I've heard the J4 cams don't line up 100%, but work. I wouldn't risk this personally, just fit JP4S cam's or a performance cam made for the JP4.

    Reason why they change springs+retainers is because the c2 VTS engine Rev's to 6500, And when you run them on saxo management.. It allows it to rev to 7200. So if it live's in high RPM, they should be upgraded
  6. Saxperience Post Whore Joined: Aug 2009 ilkeston derbyshire Posts: 9823 C2 VTR stripped, 406hdi, clio 172
    #6
    yes but whos to say the jp4 has lower miles, its not like they are new engines
  7. Established Member Joined: Nov 2008 welwyn garden city, hertfordshire Posts: 2313 s1 106 xsi
    #7
    The engine am looking at getting has 47k on it, the plan is to put the j4 springs an retainers in then get something like 708's in there. Do I buy 708's for the j4 if I use them springs and retainers?
  8. Saxperience Forum Bum Joined: Dec 2008 Lancs Posts: 4124 JP4S'd R.
    #8
    Quote:
    Originally Posted by mandyslover70 View Post
    yes but whos to say the jp4 has lower miles, its not like they are new engines
    They're newer than the J4's though, so likely to have less miles =]

    May aswell fit the whole engine instead of putting it on j4 - imo anyway (less hassle)

    the car's jp4's come from aren't likely to of been bounced of the limiter daily, Whereas a saxo VTS would more likely of been
  9. Established Member Joined: Nov 2008 welwyn garden city, hertfordshire Posts: 2313 s1 106 xsi
    #9
    Will be fitting the whole engine just changing the springs and retainers to j4 and then I'm guessing I use a j4 after market cam if I want 1?
  10. Regular Poster Joined: Apr 2008 Sheffield Posts: 276 Peugeot 106 GTi, Clio 172
    #10
    Quote:
    Originally Posted by shaneio View Post
    Will be fitting the whole engine just changing the springs and retainers to j4 and then I'm guessing I use a j4 after market cam if I want 1?
    Or just get a JP4 after market cam? Unless you've already got a j4 aftermarket cam in your current engine.

    The rumour is J4 708's in a jp4 has very close piston to valve clearance (As they are designed for the J4) so if you skimmed the head and fitted a Headgasket in a bid to lower the compression ratio as some people do, the valves and pistons may interfere.

    Just a heads up, I've not got a JP4 so can't confirm but i've read/heard about this a few times. Cams designed for that engine you won't have any issue's that's all.
    1 user thanked this post: