Z3 2.2 M54 running on "premium" unleaded

GazHyde

GazHyde

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Z4 MR
Just an observation, no real evidence of anything particularly - just something interesting I noticed.

I've always had a small flat spot at just over 4k RPM, where the car feels like it takes a short breath before carrying on. Maybe half a second, just enough to feel it.

Now the fuel price in the UK has dropped, I've only been using either Shell v-power or Tesco Momentum 99 octane fuel. I've run it for about 400 miles now, with no standard unleaded at all.

Noticed tonight on the way back home this evening that this flat spot has almost gone.
 
@GazHyde I have always run my Z3 on V-Power Nitro.. I know you can run on the normal unleaded, but for me its like an athlete, the better the product in the better the power out. Also the fuel has better additives than the normal run of the pump stuff.
 
GazHyde said:
... I've always had a small flat spot at just over 4k RPM, where the car feels like it takes a short breath before carrying on. Maybe half a second, just enough to feel it. Now the fuel price in the UK has dropped, I've only been using either Shell v-power or Tesco Momentum 99 octane fuel. I've run it for about 400 miles now, with no standard unleaded at all. Noticed tonight on the way back home this evening that this flat spot has almost gone.
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The flat spot was the knock sensor pulling the advance, crying out for the proper octane.
 
Your engine needs the extra octane to allow it to power through those flat spots that occur when running cheap gas. Have you noticed a slight increase in power and milage? Milage should be at least the same but usually is up slightly when using high octane gas. Your engine will love you longer also, so treat it nice Dad, Gaz Jr.
 
How much extra is super unleaded compared to standard fuel, 5 or 6 pence a litre?
Nobody is that skint!
 
oldcarman said:
Have you noticed a slight increase in power and milage?
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Everything seems smoother for sure, hard to tell on the power as that could only be a minimal effect at best. As for MPG, I haven't been recording that on this car.

vintage42 said:
The flat spot was the knock sensor pulling the advance, crying out for the proper octane.
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Interesting to know what might be causing it.

smartbear said:
Nobody is that skint!
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Didn't say I was skint, just a cheapskate ;). Also the nearest petrol station to me doesn't sell a premium unleaded, and did I mention I'm lazy as well?
 
Well you can have an excuse for even more driving with the top down now then lol.
 
Maybe i should start treating Panther to better fuel
 
Didn't say I was skint, just a cheapskate ;). Also the nearest petrol station to me doesn't sell a premium unleaded, and did I mention I'm lazy as well?
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Now where ..................=))

Tony.;)
 
I use Co op fuel which ever pump is free in my lunch break. I chuck an occasional bottle of fuel treatment in for good measure.

Tony.

ps. Don't notice flat spots with a "Doris" box.:ymdevil:=))=))
 
I always use Shell V-Power or whatever Optimax is now called in my M54 2.2.

My son used to have a 225bhp Audi TT and that would hit the rev limiter earlier on regular fuel than when being fed with Optimax. The ECU recalibrated the limiter accordingly, it seems.
 
That flat spot @GazHyde is talking about is quite common with infrequent servicing. Something that was very noticeable with @BMBabe on the drive home., you could almost count the seconds for the Vanos to pick up. After a full service and flush the engine never hesitated around that 4k rev range.

Lee
 
I recall we've had the `cheapskate' discussion before and the consensus was that the extra cost of fuel is compensated for in extra mpg :).
Sorry @GazHyde it doesn't help with laziness though ;)
 
jonco said:
the consensus was that the extra cost of fuel is compensated for in extra mpg
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Most likely, but as I haven't been recording my fuel consumption recently I haven't been worried. I have been driving it harder recently though, coinciding completely with the sub frame refresh. Guess that's why I thought I would make the switch over.
jonco said:
Sorry @GazHyde it doesn't help with laziness though
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Story of my life Colin!
 
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