| Author | Message | ||
     Paul Dabrowski Experienced User Username: shabbyshadow2 Post Number: 11 Registered: 9-2005 |
Had an exciting afternoon today. After 10 weeks in the panelshop at work, I finally received SRH35979 back. Apparently I have to return it in 4-5 weeks to have the final polish and blocking? after the paint has hardened properly. Having never seen my car in anything but very faded Pewter, I must admit I don't mind it. I was interesting when I parked it back at work next to a new W221 S500L Benz, and the Shadow attracted more interest from passersby! Only problem is that is very grumpy after sitting for 10 weeks and is blowing a lot of unburnt fuel. Still, something to do this weekend! | ||
| Lungmuss Unregistered guest Posted From: 195.93.21.66 |
Paul, Well done! I hope you are pleased with the new look and get even more enjoyment out of RR motoring. Regards, Clive (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 617 Registered: 4-2003 |
Hi Paul, Your post suggests your car was painted with 1K acrylic paint rather than 2K "Two Pack" paint. Did the painter use "clear-coat" over the acrylic colour coats? Depending on the number of colour coats applied by the painter, whether it has been "clear-coated" and the current ambient temperatures where you are located; I would wait as long as possible for the paint to cure before the final cut and polish to get the highest quality finish. | ||
| bob uk Unregistered guest Posted From: 80.3.64.11 |
best leave the piantwork alone until it is truely hard. While you are waiting for the paint to go completely off. Take the car for a nice long drive and this may cure the rough running because no doubt the body shop have been driving the car for a couple of yards while doing the work and "fluffed the engine up" I always get engines good and hot before I tune them because I have seen many mechanics start tuning and engine then 30 mins later the engine has to be reset because it has warmed up. I have always said that if a mechanic ( who knows what he is doing) does not start getting results in the first 5 mins then there is something else wrong. Also an engine the size of a RR V8 takes at least 10 miles to get it completely warm throughly. My car when I first drive runs very smooth after about 10 miles it runs very very very smooth and the fuel consumption drops I often get 14 mpg plus on LPG which is excellent because LPG contains less energy than petrol which at a guess would mean 16 mpg if I was on petrol. BTW. In another posting I wrote about torque convertors and said that at about 1800 rpm the convertor is stalling out and giving a 1.1:1 ratio this means that auto gear boxes are at the most fuel effeinct when the car is in top and engine doing 1800 rpm and over so at 50mph at Shadow engine is doing about 1900 rpm and it is at this speed where the least amount of fuel will be used. Standard gearing is 26mph per 1000 rpm in top gear. Slower than that and the convertor will use more fuel to run it-- faster and the wind resistance will use more fuel however at 60 mph not a lot more. At about 80 mph ( wind resistance ) the fuel consumption drops and I get about 11 mpg on LPG. I don't go much over 70 mph in the Uk because of the speed limits. which is less than 3000 engine rpm. ( max torque is at 2800 rpm which is very clever of RR to get the gearing just right for me) So a 50 mile run at about 60 mph should get the engine clear. (Message approved by david_gore) | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1046 Registered: 4-2003 |
Hang about Bob. The stall rpm is the point at which the motor rpm is restricted by the converter on full throttle with the vehicle stationary. When the driven end is at standstill, the torque after the converter is about 2.2 times the motor torque thanks to the stator inside the converter. The increase in torque does come at the price of some efficiency loss in the converter especially at low engine rpm, but it beats no multiplication while burning up your clutch with a manual transmission. The slip and stator status determine the multiplication factor, and the slip is purely dependent upon power demand and the rpm of the driven end. Once the speed increases or the demand is reduced, the multiplication factor drops to 1:1 and the stator freewheels by virtue of its sprag clutch. 1:1 torque ratio and loss-free power delivery through the converter occur at any engine speed when there is negligible slip, especially at higher rpm, and that is why the later 4L80E has a lock-up torque converter to eliminate slip at higher engine speeds altogether. Many a converter, GM 3L80 or not, has a collapsed stator sprag leading to no torque multiplication, and unbeknown to the owner. Takeoff is then sluggish (1/2 torque) and the transmission overworks the heat exchanger to the engine cooling system. See my earlier post with pictures. ps on power, at 140mph my Turbo R is ticking over at 3,900rpm (59 km/h or 36 mph per 1,000rpm nominal, vs 42 km/h or 26mph per 1,000rpm for a Silver Shadow) thanks to the taller 2.28:1 rear axle gearing. | ||
| bob uk Unregistered guest Posted From: brig-cache-4.server.ntli.net |
Sorry I am misusing the word stall. I should have said convertor at 1:1 ( note torque cons never make it 1:1 unless they have a mechanical lock like modern stuff like my Jeep which is why I quote 1.1:1 - a bit of slip) What I mean is that the convertor is not converting so to speak and not producing lots of heat and therefore not wasting fuel. It is differcult to explain how convertors actually work without a physical demonstration involving an electric fan and two other fans which free wheel and a cardboard tube. Never the less I find that most autos use much less fuel if they are driven not too slow. The gearing on Shadows is perfect for the car and me. If the engine had more torque as in Turbo R then it would pull higher gearing. Too high a gearing for a engine can be as bad as too lower. Just right is best. (Message approved by david_gore) |
