What Petrol

[Spiky 37]

just realised something, i only bought ther car last week, and i filled up with unleaded petrol

 

i've seen a few posts that people only use SUL

 

should i ONLY use SUL ??????

[scumbag 0]

When I bought mine the first few times I used normal unleaded. Ran it right down and then used super unleaded and noticed a real improvement so carried on using it ever since. This about it, it's worth it. Better fuel to run your beast with, and is only really 2p a litre more so on a full tank its only a quid or so more than normal u/l!

 

The general thing on here does seem to be use super so i'll take advantage of their experience!

[Spiky 37]

ok cheers i'll use the bp sul from now on then

[Patches 0]

SUL here too, you can feel the difference. Tesco SUL does the job nicely, know a few use it. Just for a treat I'll chuck a bit of V-power in when Im feeling flush

 

 

( which of course owning a 205, is not very often...)

 

Michelle

[Guest Dan205]

Placebo, err I mean Super Unleaded will do wonders

[Neosophist 0]

Not a lot to add but i've never noticed much difference, then again my car was designed to run on 95 ron std unleaded.

 

I guess it depends on how your engines set up? I do recall seeing that some of the super brands such as bp's have extra additives to clean the engine too which may increase performance.

 

I add a couple of spoonfulls of bio-diesel to the tank of petrol to clean the engine out, it's well-studied and talked about on the net as a good petrol-engine cleaner and emission reducer.

 

Each to his own

[Grim.Badger 15]

Your car will only really take advantage of 97-99ron if the ignition timing is adjusted for it, and if you're getting the most out of SUL then your car will pink when run on 95ron.

You may notice a difference but it wont be as much as it could be, especially for 1.9s.

[Ahl 4]

Like he^ says. The ignition must be advanced to benefit from the higher octane.

 

I disagree about the difference though - I noticed 5-6mpg less difference and a big chunk of lost power on my 1.9 (after adjusting the dizzy so it didn't pink).

1.9's were never meant to run on anything other than super though.

[Rob_the_Sparky 9]

Absolutely no point in stuffing SUL in without adjusting the ignition timing. I also had a 1.9 retarded for UL when first bought, gained both mpg and power when switching to the good stuff and adjusting the ignition to suit.

 

My 309 had a tank of UL in error (a mate was driving it) and it did pink but not as badly as might expect...

[Spiky 37]

so for SUL what should the timing be set at??? 10 degrees?

[Ahl 4]

so for SUL what should the timing be set at??? 10 degrees?

For a 1.9, whatever the book figure says as they were supposed to be run on SUL (ron 97+) from the factory.

However, the best way is to do it by ear, as is mentioned in another recent thread.

[Zed 0]

So, how about an mi engine?, any benefit to using sul on these ?

[Ahl 4]

Don't quote me on this, but I think mi16's (at least the early alloy 1.9 block) were also specified to run on SUL from the factory so you would think they would benefit.

 

You can't adjust the timing very easily as its set by the ECU though, and I've heard before that they run on normal UL with no pinking.

 

The later 2L iron block mi and possibly some of the later 1.9's have a knock sensor and so should be able to automatically compensate for UL or SUL.

[Higgy 0]

Don't quote me on this, but I think mi16's (at least the early alloy 1.9 block) were also specified to run on SUL from the factory so you would think they would benefit.

 

You can't adjust the timing very easily as its set by the ECU though, and I've heard before that they run on normal UL with no pinking.

 

The later 2L iron block mi and possibly some of the later 1.9's have a knock sensor and so should be able to automatically compensate for UL or SUL.

 

My 1.9 Mi has 3-row ECU with knock sensor. Engine is from 1990.

 

As far as I understand pinking occurs mostly (maybe always?) when the engine is under heavy load. So unless your driving at the top of the rev range a lot, maybe you will not notice the difference?

 

I don't know how quickly the knock sensor reacts? I thought it was always 'listening' and adjusting all the time?.

 

If the ECU detects pinking, retards the timing then 'stores' the info just once, then maybe you would have to reset the ECU (disconnect battery) if you switch from UL to SUL, otherwise it never adjusts the timing?

 

Going back to my point about pinking happening at the 'top end' of the rev range, if this is so, then you are only getting the 'extra' power at the top of the rev range. And I find it very difficult to detect say an extra 5bhp when at 7k rpm. Everything is already happening so fast, the extra power becomes blured.

 

This is why, when I had my 206 GTi and test drove a 206 GTi 180BHP, it did not feel any quicker. As the extra 40BHP is developed so high up the rev range you are already going quick.

 

Does it make sense?

 

Higgy.

[Faz85 0]

The knock sensor should react instantly, its quite basic, just creates an output at a specific frequency (the knock frequency of the engine)...This causes the ECU to retard the timing at that instantaneous moment. But once the knock sensor isnt detecting knock, the ECU automatically re-adjusts by advancing the timing, so there shouldnt be any need to disconnect the ECU when changing to SUL, you can just fill up and enjoy it.

 

As for when pinking occurs, it occurs at high load, so IMO depends not only on the rev range, but the gear your in, the incline of the road, the weight, the ambient temperature, the AF ratio etc..

 

Plus its worth considering that any pinking is undesirable, not only because of the reduced performance, but the risk of serious piston damage as well!

 

Faz

[Ahl 4]

My mi16 is 1989 I think - it has a two row non-knock sensor ECU and loom.

 

High load is at lower revs and larger throttle openings, not at high revs.

If you put the car into 5th at 30mph say and gun the throttle, thats when you'll hear the pinking at its loudest.

[jim21070 2]

Even for a 1.6, designed to run on 95 RON from the factory, an improvement is gained by using SUL and advancing the timing to suit. It can be advanced way up almost to the limit of its adjustment before pinking sets in.

 

V-Power works for me. Both responsiveness and MPG are up.

[GLPoomobile 958]

Isn't it funny how you'll get a different opinion at different times?

 

One month you can post a topic like this and you'll have 90% response saying use SUL, you WILL notice the difference. Another month you'll get 90% saying don't bother using it!

 

Personally I always use SUL (and had a total tantrum when I went down to Devon the other week to find all but one Service Station had closed down locally, leaving one which was now a Jet, and didn't sell SUL, so I had to drive miles to a Tesco in the next town). I can't say for certain that I have ever noticed much difference, but I justify it because a few pence per litre really doesn't make a lot of difference in the bigger picture (just don't let the Government hear me say that!) and I'd rather have the peace of mind thinking I'm giving my car something healthier.

 

Call me a sheep, I don't care!

[Ahl 4]

Isn't it funny how you'll get a different opinion at different times?

 

One month you can post a topic like this and you'll have 90% response saying use SUL, you WILL notice the difference. Another month you'll get 90% saying don't bother using it

Sounds to me that one month you've had everyone who knows what they're talking about and understands the concepts of how it all works replying, and the next month we've all been on holiday!

 

If you can adjust the dizzy or remap it etc, then it should always give you a gain. It also works out cheaper per mile for me to use V-power than normal UL!

[Faz85 0]

Personally I always use SUL (and had a total tantrum when I went down to Devon the other week to find all but one Service Station had closed down locally, leaving one which was now a Jet, and didn't sell SUL, so I had to drive miles to a Tesco in the next town).

 

I get quite annoyed by that myself, there was a shell garage conveniently located 5 minutes from my house which was great news until a few weeks ago when I kept arriving to find all the V-Power pumps had been blocked off...of course a week after that, and its transformed into a BP garage instead. Of course BP still does SUL but im quite particular when it comes to my fuel!

 

On the odd occasion I get forced into buying regular unleaded if im in an unfamiliar place, but I keep a couple of bottles of Millers CVL turbo in the glovebox just in case (supposedly adds 4 octane points)

[KRISKARRERA 2 1 Cars]

Officially only 405 1.9 Mi16s from chassis number 70000000 onwards, which according to Peugeot is model year 1991 H reg. (In other words this is when they got knock sensors from).

Mi16s prior to that are supposed to only be fed super unleaded. I never heard or saw any damage using reg s*itty unleaded but it defo goes better with the correct octane so now I always use V power.

[Ryan 99]

Also the 2-row Mi16 loom has a pair of spade connectors near the ECU which are apparently for connecting an octane coding plug, allowing to you fit a resistor between them and the ECU will adjust the timing, idle speed and fueling for different octane ratings. The local citroen garage is looking into it for me. The peugeot dealer looked at me like I was mental when I mentioned it.

[Ahl 4]

Also the 2-row Mi16 loom has a pair of spade connectors near the ECU which are apparently for connecting an octane coding plug, allowing to you fit a resistor between them and the ECU will adjust the timing, idle speed and fueling for different octane ratings. The local citroen garage is looking into it for me. The peugeot dealer looked at me like I was mental when I mentioned it.

Thats quite interesting. Keep up updated.