The Posh Thread. 1991 Bentley Turbo R.

Brings back a lot of memories.  Chuck, the guy that taught me how to hold a wrench, worked exclusively on Italian and English exotics. His favorites were Jags, but he particularly liked giving Rolls and Bentleys a good "Italian tune-up"

Said the cars never get pushed near the limit cause everyone that owns them is old and drives like it, so the last thing he'd do when he finished working on a customer's car was put on a nice suit, get the thing on the interstate and mat the gas till it got to triple digits. 

"No cop ever pulls over a speeding Rolls Royce thats driven by someone that looks like they have money." he told me.

You got a beaut there. 

In reply to solfly :

Engine pictures. I'm not sure how I overlooked them. 

The beast in question is a 6.75L aluminum block pushrod V8. Commonly called the 6-3/4. It has a Garret turbocharger that puts out around 7 pounds of boost. That gets you somewhere around 330 hp at 4200 rpm and over 500 lb-ft of torque at 2000 rpm. Bentley doesn't actually advertise the HP and torque ratings beyond calling them adequate. Redline is at 4500. This engine went into production in 1959 and was discontinued in 2020. Over the 61-year span, they only made 36000 of them. Power output ranged from 172 hp to 530 hp and 295 lb-ft to 811 lb-ft of torque. In its latest, mightiest iteration, the twin-turbo version delivers 811 lb-ft at only 1,750rpm. Those are diesel numbers.

The engine is very quiet and very smooth. Inside the car, you hear nothing until the go pedal is mashed flat. Then you get a slight rumble from the back of the car and it builds speed with authority.  

This version is tied to a GM Turbo 400 transmission and runs back to a limited-slip differential. This combination moves the 5400 pound car with ease.  

I understand goofy stuff like this braking system on pre-war cars. After all, there was no established way of doing things and everybody was trying stuff and making improvements left and right.

But 1991?! Wtf were they thinking... we'd had brakes figured out for 30 years.

Does it have ABS?

I would be really tempted to put an exhaust cutout on that beast!  Cruising along, nice and serene.  Step on the go pedal and open the valve.  Might not be going fast but it would probably sound good doing it!

In reply to Toyman! :

I love the onset of speed in some of these giant euro sedans. I can't help but to imagine a modern turbo that's perfectly sized for this engine being installed. I'm sure the gradual increase of speed is similar to the 6.0 biturbo v12 Benz in a s600.

In reply to Tom Suddard :

It does. In the second picture, to the left of the shock tower, you can see what I'm 90% certain is the ABS unit.

Studying the car, it looks like Rolls and Bentley did a lot of things simply because that's the way they always did them. 

In reply to PMRacing :

0 to 60 is under 7 seconds. The top speed for the Turbo R is 146 mph. It apparently doesn't take too long for it to get there. Slow it isn't.

So it is quintessentially "British" in how tradition in design was maintained. 

Is that K-Jet fuel injection or something more unique to Rolls/Bentley?

In reply to Ian F (Forum Supporter) :

It's a standard Bosch K-Motronic unit that was also used in several BMWs of that era. It's fairly well understood. I hope I never have to touch it. 

yupididit said:

In reply to Toyman! :

I love the onset of speed in some of these giant euro sedans. I can't help but to imagine a modern turbo that's perfectly sized for this engine being installed. I'm sure the gradual increase of speed is similar to the 6.0 biturbo v12 Benz in a s600.

It's interesting. My Touareg hits like a sledge if you stomp the pedal to the mat. This is more like a smooth, silent, rocket. It seems to gradually accelerate and just keeps on accelerating. From the 500 rpm idle to the 2000 rpm max torque it builds speed almost logarithmically. It gently pushes you back in the seat and then you are going 90 mph and wondering how you got there. As a man who loves torque over hp, it's glorious. 

I could spent much time just staring at this thing admiring it's design... quirks.

Very jealous over here.

In reply to Toyman! :

Exactly, not super dramatic but next thing you know you're at 90 then 120 then 140 lol. 

I admire your courage.  You are indeed a better man than I. 
  The only thing I can add is the definition of 

                POSH 

   Stands for;  PORT OUT, STARBOARD HOME. 
   When traveling to India on the old sailing ships the Port ( left ) side of the ship was cooler   When traveling from India to home the starboard side was cooler. 
 

Federal Lotus Europa Twin Cams have two remote mount brake boosters....and miles of brake lines since they are in the engine compartment...

Saturday was tied up helping my parents figure out why their house filled with electrical smoke. 

This morning I ran down to the office and picked up the Bentley. I was 90% certain the drivers rear suspension was the one locked up so I started on it first. Step one is disassemble half the trunk. Good news, Bentley doesn't use any snap  clips or plastic push things. There are no plastic panels. Just wood, leather, and carpet. Everything is held together with Phillips head screws. 

Bad news, the accumulator is wedged in by the trunk lid hinge. There is very little room to work around it. On the recommendation of a Rolls Royce mechanic I ordered a Knipex 22" pliers. They were the ticket to getting the thing loose, 1/8 turn at a time. 

I had to enlist a set of smaller hands to reinstall it. Holding up 5 pounds of steel with the fingertips of one hand while trying to start threads is surprisingly difficult. There was no way I was getting both hands in there. Overall, I'd give this repair a 2-3. A bit of a PITA but not too bad and I didn't get greasy.

That side done, I took it for a spin around the neighborhood.  The suspension is fixed. I will put the extra accumulator on the shelf for future use. This repair also helped the brakes out a lot. They are nowhere near as twitchy as they were. I'm going to leave them alone until I flush the entire system. 

That done I took it for a cruise and took the family to dinner. I really do love this car. 

We rolled back into the office, got the car under cover, and as we were climbing in the XJ to head home the sky let loose. It had been dry all day. Even mother nature likes this car. 

More as it happens. 

Toyman! said:

This is more like a smooth, silent, rocket. It seems to gradually accelerate and just keeps on accelerating. From the 500 rpm idle to the 2000 rpm max torque it builds speed almost logarithmically. It gently pushes you back in the seat and then you are going 90 mph and wondering how you got there. As a man who loves torque over hp, it's glorious. 

Everybody loves torque over horsepower... they just don't understand it well enough to know that. 

Toyman! said:

yupididit said:

In reply to Toyman! :

I love the onset of speed in some of these giant euro sedans. I can't help but to imagine a modern turbo that's perfectly sized for this engine being installed. I'm sure the gradual increase of speed is similar to the 6.0 biturbo v12 Benz in a s600.

It's interesting. My Touareg hits like a sledge if you stomp the pedal to the mat. This is more like a smooth, silent, rocket. It seems to gradually accelerate and just keeps on accelerating. From the 500 rpm idle to the 2000 rpm max torque it builds speed almost logarithmically. It gently pushes you back in the seat and then you are going 90 mph and wondering how you got there. As a man who loves torque over hp, it's glorious. 

I wonder how much of that is due to the influence of SU carbs and such on other British luxury cars?  As I remember, they don't really have a secondary that opens like most American cars, they just scoot.

frenchyd said:

I admire your courage.  You are indeed a better man than I. 
  The only thing I can add is the definition of 

                POSH 

   Stands for;  PORT OUT, STARBOARD HOME. 
   When traveling to India on the old sailing ships the Port ( left ) side of the ship was cooler   When traveling from India to home the starboard side was cooler. 
 

Turns out that's not true, though lots of people think so: https://www.merriam-webster.com/help/faq-posh

In reply to Mr_Asa :

This one is efi, so no secondaries. 

I think a lot has to do with how the power comes in. Tall gears mean the initial thrust is pretty gentle. By 1500 rpm the turbo is spooled up and by 2000 rpm there is over 500 lb-ft of torque on tap. But it comes in so smoothly its almost unnoticeable. With a 4500 rpm redline the engine never screams. It's just a soft rumble. 

The 1-2 shift doesn't happen until around 55 mph and it doesn't bang into second, it just shifts and keeps on pulling like a freight train. It's like the car isn't working hard at all. No drama, no screamin rpms, no noise, it just goes like stink without a fuss.

It's simply amazing. 

In reply to Toyman! :

No, I get that.  I mean that traditionally British luxury has included this very smooth transition and despite how much the world has changed and the changes in technology they retain the characteristics of their origin because over the years that's what luxury means to their clientele.  Its kinda like how the suspension and brakes are roughly the same system despite the advances in everything else?

The more things change, the more they stay the same, kinda deal.
 

Outstanding that you got away with only replacing the one.  I hope the luster never wears off this car. At least until a new love interest winks at you, lol.  If Mother Nature is on your side, I think you may have this licked.  Although not the same, I find in my Jag, getting to "goodbye license" speed, happens pretty quickly.  Not neck snapping, but smoothly gets you there.  That alone must be a big attraction to your Bentley.  Happy motoring!

In reply to Mr_Asa :

You are right about that. 

I am 100% certain that the British are big on tradition. I would also say that Bentley's customers are as well. They tried to replace the 6 3/4 engine with the BMW 4.4L twin turbo V8 in the late '90s and their customers raised hell. They went back to the 6 3/4 in '01-'02 and continued to use it through '21. 

One thing to be aware of, being a British car, is that they're almost certainly Pozidrive screws as opposed to Philips. Its really worth getting a set of screwdrivers/bits so you don't strip the heads. 

In reply to garethashenden :

I'll have to study the screws a little closer.

Good info, thanks!

Very cool! 

I once saw a cheap Bentley that I seriously considered at a price so cheap I kick myself that I didn't get it. It was driven a lot harder than yours and was in ok shape rather than great shape.

But it had a brake problem and at the time the common knowledge said that the problem was fixed by throwing extreme amounts of money at it and praying. That was pre-GRM me and I'm very intrigued to see how you fix it