1998 S70 GLT TURBO questions

[jblackburn]

That lower intercooler hose (directly from the turbo) gets squishy with oil with age. That means it's prone to blowing off and leaving the car power-less in the middle of the road.

If they're squishy or oil-coated, they're a candidate for replacement. Also, too much oil in the hoses means that your car needs a PCV job - badly.

[cn90]

That lower intercooler hose (directly from the turbo) gets squishy with oil with age. That means it's prone to blowing off and leaving the car power-less in the middle of the road.

If they're squishy or oil-coated, they're a candidate for replacement. Also, too much oil in the hoses means that your car needs a PCV job - badly.

As far as I can tell, that hose is slightly coated with oil but seems OK, still soft and pliable.
I will clean it up and watch for oil leak.

I just verified the PCV system, it is still factory at 145K!!!
The elbow hose (from the PCV Trap to the top of the engine) is rock hard!
PCV refresh is on the list but it is too cold now, 32F today.
Maybe in the Spring of 2013 when the birds migrate back here.

[850 LPT]

Can't run regular gas though, 89 or higher only. I'm actually looking for an N/A (not too too seriously, but....) with the thoughts of better economy via regular fuel, but for what it's worth, any Volvo white motor, blasted or regular seem to run forever with proper care.

Sorry to be the bearer of bad news but the NA cars have higher compression ratio and are suppose to use 91+ octane. Your GLT should run fine on 87+ octane, however you are suppose to run 91+ in that car as well. Our car runs strong in heat or colder weather. You may want to check that out. Plugs, wires, etc.

Congrats on your purchase! I hope you enjoy it.

I just wanted to share some slightly different experience as far as types of gasoline.

I've owned my 97' 850 GLT (same engine as 98' S70 GLT) for over 10 years now and it ran just fine on regular gas all this time. Every now and then I experimented with higher grades but to me they made no difference performance or mileage wise exept cost more. The car now has more that 232 k on it and runs as strong as ever. In fact, it blows me away how powerful it is still at this age.
My "new" V70XC has vitually the same engine and therefore gets the same type of gas. And again, I don't see any reason to spend money on higher grades if I don't feel any improvement.

Dirk

[jblackburn]

Can't run regular gas though, 89 or higher only. I'm actually looking for an N/A (not too too seriously, but....) with the thoughts of better economy via regular fuel, but for what it's worth, any Volvo white motor, blasted or regular seem to run forever with proper care.

Sorry to be the bearer of bad news but the NA cars have higher compression ratio and are suppose to use 91+ octane. Your GLT should run fine on 87+ octane, however you are suppose to run 91+ in that car as well. Our car runs strong in heat or colder weather. You may want to check that out. Plugs, wires, etc.

Congrats on your purchase! I hope you enjoy it.

I just wanted to share some slightly different experience as far as types of gasoline.

I've owned my 97' 850 GLT (same engine as 98' S70 GLT) for over 10 years now and it ran just fine on regular gas all this time. Every now and then I experimented with higher grades but to me they made no difference performance or mileage wise exept cost more. The car now has more that 232 k on it and runs as strong as ever. In fact, it blows me away how powerful it is still at this age.
My "new" V70XC has vitually the same engine and therefore gets the same type of gas. And again, I don't see any reason to spend money on higher grades if I don't feel any improvement.

Dirk

I guarantee you it's pulling timing somewhere along the way. Try a tank of 89-93 in one of them, and then reset the engine computer by pulling off the negative battery cable.

Both of my turbo cars run terrible on 87 octane.

[850 LPT]

Sorry for the dumb question, but what do you mean by "pulling timing"?

I'm pretty sure I'm not getting codes in either of my cars from this, could you tell me what to look for? I'm kind of curious now.

[jblackburn]

When the knock sensor detects knock (these days, it can hear things you can't - not like with older cars), it retards timing a bit to prevent pre-ignition as much as the car can. This results in a bit of wasted fuel and power.

Here's a graph of the Cruze pulling timing going up a hill in 5th gear (~2000 RPM) running 87 octane. You can feel the car "pulsing" along with the corresponding peaks in the graph as it cuts power in and out going up the hill. They say it can run "fine" on 87 octane, but that's just not true.

30sec.png (452.15 KiB) Viewed 1078 times

I've noticed on the T5 motor, running 87, it is INCREDIBLY slow during the summer below 2500 RPM. Hit the gas hard, and you can just feel the engine bogging down; and it feels a bit weaker throughout the whole rev range and slower to respond than it is on 89 or 93. The T5 motor is already slow before the turbo picks up, so that doesn't help much. I usually ran 89 in the S70 unless it was 90+ F outside.

[850 LPT]

Thanks for explaining this in so much detail, it does make a lot of sense now. What I think is happening is that the effect of this is far less noticable (if at all, since I never did) in an LPT car vs. an HPT or NA.
This is just my theory, but maybe the LPT is simply masking the negative effect by providing so much low end power. But it would probably still make sense to upgrade to higher grade fuel.