Mi16 fuel octane rating
  • Register
  • Help
Results 1 to 18 of 18
  1. #1
    1000+ Posts
    Join Date
    Jul 2001
    Location
    Perth, Western Australia
    Posts
    6,494

    Default Mi16 fuel octane rating

    Is it worth running an Aus spec Mi on Ultimate (or other 98 RON)?

    I know they're OK on 91, but I've seen a few posts where people are getting better consumption on 98 which is making up for the cost difference. Is this wishful thinking, or is the consumption that much better? May as well have my cake and eat it, if this is the case.

    On a side issue, where's the knock sensor on the 1.9? - somewhere on the head according to Mr Haynes, but I thought they were usually on the block.

    Thanks...

    Stuey

    Advertisement


    2003 PEUGEOT 206 GTi

  2. #2
    Fellow Frogger! pips's Avatar
    Join Date
    Dec 2004
    Location
    Behind you
    Posts
    487

    Default

    I think its worth running higher octane for the cost. You do get better fuel economy. But it varies between engines, and their state of performance.

    I can't say for certain, but logically, I would assume that the knock sensor is on the head, not the block. Its not directly connected to the combustion chamber. I think (and correct me if I am wrong) they have a quartz crystal or something in them that detects vibrations from detonation. And sends a small reference voltage to the ECU. to retard ignition, etc.

    Like I said, I don't really know, but just sound logical to me, the way I put it.

    pips

  3. #3
    Moderator Alan S's Avatar
    Join Date
    Mar 2001
    Location
    Queensland, Australia
    Posts
    8,923

    Default

    I've run mine on ULP and it's quite acceptable in fact my handbook I'm sure says 93 octane or upwards.
    I normally use PULP but have had Ultimate and Optimax in it and I can't feel or notice any difference in either consumption or performance.
    There is a slight difference between ULP & PULP (mainly as regards smoothness & flexibility more than power gain) but above that it seems irrelevant and to me a waste of money.
    Biggest difference I ever felt in any motor without doubt was when I put Ultimate in the CX, old style carby/coil ignition system but with a high compression engine....WoooHoo didn't she ever sing..
    I think with the 16V/Mi16 set up, EFI etc, that a lot of variances are catered for in the engine management system.



    Alan S
    If it ain't broke, use a 12" shifter.....that usually does the trick!!

  4. #4
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,483

    Default

    Besides the performance improvement, there's definitely a difference in running costs between ULP and PULP. ie it costs less per km on PULP.

    The knock sensor is near the oil filter.
    Attached Thumbnails Attached Thumbnails Mi16 fuel octane rating-knocksensor.jpg  

    '92 205 Mi16
    '90 Mi16x4

  5. #5
    Fellow Frogger!
    Join Date
    Oct 2000
    Location
    Auckland, New Zealand
    Posts
    533

    Default

    I don't know why you'd even consider running an Mi16 on 91 Octane petrol.

  6. #6
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,483

    Default

    Quote Originally Posted by Louis
    I don't know why you'd even consider running an Mi16 on 91 Octane petrol.
    In 1990 there wasn't a choice. But now there is........

    '92 205 Mi16
    '90 Mi16x4

  7. #7
    Fellow Frogger!
    Join Date
    Oct 2000
    Location
    Auckland, New Zealand
    Posts
    533

    Default

    I presume this was the case in Australia and not New Zealand?

    The two XU engined Peugeots I've owned have either pinged or not run on 91 Octane petrol so I presume New Zealand had access to higher octane petrol in the past.

  8. #8
    Member
    Join Date
    Sep 2004
    Location
    Adelaide
    Posts
    90

    Default

    Manufacturers alway map their ECUs for worst case situations - eg 91 RON fuel being the best available, meaning longevity and fewer warranty claims, but a drop in performance. If 91 RON is specified,in your handbook, then you are wasting your money using higher octane fuel as the parameters of the ECU will not advance the spark sufficiently to take advantage of the extra bang offered. If you can find an aftermarket download/upgrade for the ECU then 98 certainly makes sense.

    RSC 172

  9. #9
    1000+ Posts
    Join Date
    Jul 2001
    Location
    Perth, Western Australia
    Posts
    6,494

    Default

    Alan, Peter - thanks.

    Louis, I have every document that came with the car and the original info sheet clearly states 91 RON minimum. It runs fine on 91 - as in limited pinging and otherwise OK - so...???

    Pips, I assumed the head would give too many false signals, borne out by Peter's confirmation that it's in the block - like in every other car I know about. Some are directly connected to the main bearing cap via a bolt. A test for the knock sensor is to strike it with a screwdriver. I can imagine that the commotion in a head would be too much for it... Thanks anyway.

    Cheers

    Stuey


    2003 PEUGEOT 206 GTi

  10. #10
    Fellow Frogger!
    Join Date
    Aug 2003
    Location
    Perth
    Posts
    924

    Default Ultimate

    Ran mine on Ultimate and noticed a big difference in smoothness and the way it loved to rev out. Cany say it felt a lot more powerful just happier!

    Graelin

  11. #11
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,483

    Default

    Quote Originally Posted by Stuey
    Some are directly connected to the main bearing cap via a bolt.
    Stuey
    ditto Mi16. That bolt holds the centre cap in place.

    '92 205 Mi16
    '90 Mi16x4

  12. #12
    Fellow Frogger!
    Join Date
    Oct 2000
    Location
    Auckland, New Zealand
    Posts
    533

    Default

    Stuey, O.K. well the 405 Owners Handbooks I've looked at including mine specifically state 97 RON and 95 Unleaded RON petrol.
    Last edited by Louis; 13th December 2004 at 09:15 AM.

  13. #13
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,261

    Default

    Quote Originally Posted by Louis
    Stuey, O.K. well the 405 Owners Handbooks I've looked at including mine specifically state 97 RON and 95 Unleaded RON petrol.
    Is that for the 8V or 16V engine?
    The 16V is OK for 91 octane whereas the 8V is not. The owner's handbook states this.
    This is due to the more sophisticated engine management on the 16V.
    Graham

  14. #14
    Fellow Frogger!
    Join Date
    Oct 2000
    Location
    Auckland, New Zealand
    Posts
    533

    Default

    Yes I am aware that the 8V lacks the ignition aspect that the Motronic system features.

    The handbook covers both the XU9J2 and the XU9J4.

    I can only presume that as PeterT has mentioned at this time in Australia there was no choice other than 91. Whereas in Europe and so on they had access to 95/97 RON petrol.

    The handbook lists

    Unleaded 95 RON min: Mi16 - 'DO NOT USE'
    GTX-GRi-SRi - 'Retard 2deg'

    It lists 'YES' to leaded and unleaded 97 RON min.

  15. #15
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,261

    Default

    Quote Originally Posted by Louis
    Yes I am aware that the 8V lacks the ignition aspect that the Motronic system features.

    The handbook covers both the XU9J2 and the XU9J4.

    I can only presume that as PeterT has mentioned at this time in Australia there was no choice other than 91. Whereas in Europe and so on they had access to 95/97 RON petrol.

    The handbook lists

    Unleaded 95 RON min: Mi16 - 'DO NOT USE'
    GTX-GRi-SRi - 'Retard 2deg'

    It lists 'YES' to leaded and unleaded 97 RON min.

    I'm not sure when 95 octane ULP was introduced but certainly before 1992, my 205 Si specifies this where the Series 1 GTI had lower compression and would run on 91.
    Graham

  16. #16
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,483

    Default

    UK spec. Mi16's, ie XU9J4 with 10.4:1 were always 97 RON.
    Aus spec. Mi16's ie XU9J4Z with 9.7:1 were 91 RON minimum. When the Mi16 was released in Australia in 1989, ALL cars had to run on 91 in order to get compliance. The knock sensor allows the ignition to advance to optimise the octane rating of the fuel being used.

    '92 205 Mi16
    '90 Mi16x4

  17. #17
    1000+ Posts
    Join Date
    Jul 2001
    Location
    Perth, Western Australia
    Posts
    6,494

    Default

    Quote Originally Posted by Louis
    Stuey, O.K. well the 405 Owners Handbooks I've looked at including mine specifically state 97 RON and 95 Unleaded RON petrol.
    Louis, the handbook itself does, but with mine there's a clear plastic pouch in the back of the 'leather' cover containing the 'Driveway Service Data Peugeot 405'. On this, it has 'Minimum Octane rating RON 91 ULP'.

    In the official 'Australian Supplement' that's also with the books, it states that 'All Peugeot vehicles are designed to operate satisfactorily on 91-93 RON ULP...The high efficiency engine of the Mi16 vehicle features a detonation sensor system enabling satisfactory operation on unleaded petrol having a minimum RON of 91. This system also enables advantages to be obtained from commercially available unleaded petrol having a higher RON by automatically adjusting the engine management system.'

    Cheers

    Stuey


    2003 PEUGEOT 206 GTi

  18. #18
    Fellow Frogger! pips's Avatar
    Join Date
    Dec 2004
    Location
    Behind you
    Posts
    487

    Default

    Pips, I assumed the head would give too many false signals, borne out by Peter's confirmation that it's in the block - like in every other car I know......<snip>
    I knew I'd be wrong, but I was only saying that based on my knowledge of bikes. Most of the newer EFI bikes have knock sensors right on the bottom of the head, I'd say the quartz crystal or whatever it is they use would be located the inlet and exhaust valves, right near the edge of the combustion chamber.

    I guess the moral of my story is to never assume. But its sure as hell fun. I prefer being proven wrong. I get to learn new things.

    pips

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •