Premium fuel ?

Post by **fields 100** » 10 Apr 2011, 21:23

Hi, I would like to check upon the issue on the Premium vs. Regular.The cost of the gasoline is not the factor in this discussion- it is overwhelming opinion in this forum that the regular is a No-No for the T5, and yet the manufacturer clearly states that is it permissable and allowed. Granted, the car performs better on the Premium, but is using the regular gas that detrimental to the engine? Thanks.

Post by **matthew1** » 10 Apr 2011, 21:32

Not detrimental to the longevity, but detrimental to the power and efficiency.

Especially in summer in my 850 T5 I can feel reduced performance with 87 grade. It just "dogs".

Search the forum for a little more on this -- I've written about how the higher gasoline prices climb, the more affordable premium becomes because it's generally tied to the price of low grade + 10 cents. Strange but true.

Post by **VCA** » 10 Apr 2011, 21:35

fields 100 wrote:Hi, I would like to check upon the issue on the Premium vs. Regular.The cost of the gasoline is not the factor in this discussion- it is overwhelming opinion in this forum that the regular is a No-No for the T5, and yet the manufacturer clearly states that is it permissable and allowed. Granted, the car performs better on the Premium, but is using the regular gas that detrimental to the engine? Thanks.

Assuming the knock sensors are operating properly, the ECU will automatically retard engine timing and prevent knock and detonation. However, I did notice with my S70 GLT that the savings from not dispensing premium (93) fuel were offset by the car's poorer economy on regular (87). The 30 cents/gallon saved were eaten up by an almost 1.5mpg drop in fuel economy in my (decidedly mixed) driving cycle. I have not had my S80 T6 long enough to establish its long-term averages on premium, let alone on regular, so it may be different/better/worse for newer cars.

Post by **pkc303** » 10 Apr 2011, 21:38

On both of our 850's and the V70 we use premium. The difference can be felt in the performance and the gas milage.

Post by **kcodyjr** » 10 Apr 2011, 21:43

Cost and performance both put aside, then.

Consensus seems to be that it's OK unless it produces knocking the ECU can't correct, which is likely with turbos.

The NA's would probably run on bullpiss if you could get the bull to cooperate. 87 produces no ill effects that I've seen.

No longer discounting performance, it seems 87 is notably worse than 89 in the turbos.

I use 91 in my 97 GLT because I try to really baby that car. Mom ran the 96 on 87 for 133K. I usually go for 89 for the zip.

You should do the math in terms of miles per dollar before deciding on a grade.

Post by **jblackburn** » 10 Apr 2011, 21:58

I compromise and use 89 most of the year. It doesn't dog down like it did when I tried regular, and it doesn't have as much power with your foot to the floor you get with 93, but I usually don't drive like that anyway. Gas mileage is exactly the same as using premium.

In summer, during the real hot months, I run premium (93). The AC feels like it takes a lot out of my car.

gilhuly · Post by **gilhuly** » 11 Apr 2011, 07:42

I haven't noticed any degradation in power using 89 recently. I wouldn't use 87.

Post by **jimmy57** » 11 Apr 2011, 08:41

The only time 87 octane can be a problem is if it i used in mountainous driving with car loaded. The engine temp can be much higher in that situation on turbo engined models.
For many drivers who drive gently, the engine output may not approach levels where the knock will be produced and then detected and result in adjustments to power level.
If you use it and see no negative effects that YOU can feel then use it.
I have T5 powertrain 98 v70XC and I have not had any obviously noticeable effects on it. I have been driving a 99 S80 T6 and its behavior on 87 is AWFUL. It is fine on 89.
I have run 87 in several XC90's, P3 S80's, P3 XC70's, and a P3 S60 and most of those were symptom-free on 87. The 3.2 6 cylinder is the only engine that seemed to have noticeable performance loss.
The XC90 with V8 seemed to not suffer at all.

Post by **fields 100** » 11 Apr 2011, 13:27

jimmy57: thanks a lot for the detailed info. I have driven my 98 T5 43K since new and, as you have mentioned, never noticed any adverse effects related to the fuel grade. Mileage concerning: 19,9 in the city, 29.0 mpg on the highway on the 87. (Granted- my back seats are brand new: never more than 2 people in the car).

KEWROCK · Post by **KEWROCK** » 11 Apr 2011, 15:05

I asked this same question about 6 months ago and was told 87 can burn Volvo exhaust valves in the summer. I always used 87, and never noticed any ill effects on any of my cars except a supercharged Thunderbird. That one wouldn't run on anything but premium. It would run noisy and extremely hot at the edge of the safe zone on the guage.

The Volvo T5 runs the same no matter what I use. Quiet, same temp, exact same mileage, and no noticeable power difference. But this summer I might jump up to 89, at least while I'm in Florida .