Is the TU5JP4-S more economical than TU5J4?

  1. Infrequent Poster Joined: Feb 2011 Posts: 125
    #1
    Is the C2 vts engine more economical than the saxo vts one?. According to manufacturers figures it's 8 mpg more combined. That's in a c2 to, so certainly would be even better in Saxo with less weight. thanks
  2. Regular Poster Joined: Apr 2008 Posts: 343
    #2
    Im running a JP4 with J4 cams and valve springs. its noticeably better on fuel and a miles more driveable engine. 125 miles to £20 driving to work which is 75% town driving and being sat in traffic.
  3. Regular Poster Joined: Sep 2008 Posts: 449
    #3
    my jp4 in my track car... which is a 110bhp spec ... not fitted j4 cams yet seams very good on fuel
  4. Saxperience Forum Bum Joined: Dec 2008 Lancs Posts: 4124 JP4S'd R.
    #4
    My JP4S engine used to struggle getting 60 miles to 10 litre's.

    Found it had a leaky injector lol. Since fixing that, I got 78 miles from 10 litres with 2 spirited drive's.

    Which is alot better, i'll take it easy on the next 10 litre's.. see what it get's.
  5. Established Member Joined: Sep 2010 Posts: 1368
    #5
    Quote:
    Originally Posted by Mini-valver View Post
    Im running a JP4 with J4 cams and valve springs. its noticeably better on fuel and a miles more driveable engine. 125 miles to £20 driving to work which is 75% town driving and being sat in traffic.
    how do you drive?

    with my xsi i am getting roughly 120 miles to £20, driving to work, although there are a few places that i do give it a boot full. lol
  6. Saxperience Post Whore Joined: Dec 2006 Maidstone Posts: 8210 Golf TDI
    #6
    120 miles to £20 (15 litres) in the J4 I have
  7. Saxperience Forum Bum Joined: Jan 2003 Scotland Posts: 3380
    #7
    main difference in fuel economy between the engines is the management system and the emission specs the ecu is set too + fly by wire throttle .
    even the latest j4 engined saxo,s ran quite a bit richer than any tu5jp4 .
    tu5jp4 runs lambda 1 up to 100%throttle angle up to 5000rpm ,then open loop omly above 90%throttle up to rev limter+ never any acceleration fuelling to the extent of the j4
    j4 only ran lambda1 up to 4k and 70% throttle angle at any rpm and open loop above 4k+70%throttle
    jp4 very slightly higher comp as well
  8. Saxperience Forum Bum Joined: Dec 2008 Lancs Posts: 4124 JP4S'd R.
    #8
    Pretty much all jp4's in saxos are running on J4 management though, so i imagine they won't be as good on MPG as the C2 with the proper ECU.