| Author | Message | ||
     Cliff Biggs New User Username: cliffy Post Number: 13 Registered: 09-2021 |
Went for a drive to a city about 40 miles away today The roadway speed limit is 80 MPH. I started out at an elevation of @3000 feet and climbed to an elevation of @6500 feet above sea level. Numerous long hills had to be climbed at road speed. In most of the long hills I noticed that the power of the engine just wasn't there to keep up to road speed even when planting the pedal to the metal. The car would just barely make 75 MPH on two of the hills. Every thing else seemed normal. Now I realize that at an elevation of 7500 feet any normally asperated engine will only produce 75% of its sea level horsepower but I would have thought that a Rolls would be able (even at 75% power) to keep up to road speed. Checked gas mileage when I returned later in the day and it was @ 12.5 MPG for the trip. Anyone with any experience or thoughts on this? | ||
| David Gore Moderator Username: david_gore Post Number: 4023 Registered: 04-2003 |
First thing I would check is your engine timing, It should be around 6 degrees BTDC [Before Top Dead Centre] for 95RON fuel. Inability to accelerate is usually a symptom of retarded timing and would be my first check. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2480 Registered: 09-2004 |
Is the car the later 86 type with fuel injection if not then IMO check air filters first. Is the temp getting to normal. Have known the thermostats to stick open causing running rich etc. | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 705 Registered: 11-2017 |
Thermostat is not the issue since it runs fine at lower altitudes. It's a combination of altitude and possibly timing. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2481 Registered: 09-2004 |
Robert do enlighten my self and others on "runs fine on lower altitudes" with carbs and of course the difference with the fi systems with the higher altitudes ? | ||
| Cliff Biggs New User Username: cliffy Post Number: 14 Registered: 09-2021 |
My first thoughts also ran to timing and air filter Its an injected system Runs good on the level at 3000' above sea level. Runs smooth, starts cold nicely with no shake to speak of. All gages in the "green" so to speak. Just did 300 miles in 2 days on the highway with NO issues what so ever except for all the folks that stopped me while parked and wanted to talk about the car :-) It does draw attention. Pulling the air filter can today to look at it. | ||
| Cliff Biggs New User Username: cliffy Post Number: 18 Registered: 09-2021 |
Unfortunately we only have 91 RON fuel available in my area so ignition timing "may" have to be compromised when I get to rechecking it again. Now I am trying to keep up with traffic at 75-80 MPH uphill at 6700 altitude (road speed limit is 80 MPH) Its pedal to the metal trying to keep up. | ||
| Cliff Biggs Experienced User Username: cliffy Post Number: 95 Registered: 09-2021 |
I have just replaced my WUR (I'll do another thread on it) as California delivered 86 FI SZs needed the -093 altitude compensating WUR and not the normal -088 WUR. After the change it runs a lot smoother but haven't gone uphill yet due to snow 40 miles north. |
