90s Bentley

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ingenieur

Original Poster:

4,170 posts

187 months

Friday 18th March 2022
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I've been thinking about buying a 90s Bentley for about 10 years.

I thought I wanted a long wheelbase turbo R. Or a turbo RT (they're all long wheelbase?)

But recently I've seen a Brooklands which ticks a lot of boxes.

I know a lot of people on here have had the Bentley and I just wondered if anybody knows whether or not it is simple to tune a Brooklands to Turbo R performance? I think the Brooklands is 300hp and that's not going to really do much in a car that size. The performance was part of the reason I wanted it, not all of the reason but I wouldn't be interested in the non-turbo, so part of it.

TarquinMX5

2,018 posts

86 months

Friday 18th March 2022
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When you say Brooklands, I'm assuming that you mean the 90's SZ model, not the later Brooklands 2-door?

The Brooklands weren't 300bhp, only the later late-96 onwards Brooklands R (which was a light-pressure turbo) was 300bhp, made until the end of '97. Brooklands were naturally aspirated.

There were so many changes to the specifications from the late-80s that it's difficult to come to any firm conclusion about 'tuning'. Several engine management systems were used, different / intercoolers, different heads - over the life of the Turbo R the power output was gradually increased by approx 30% - you couldn't simply drop it in to a garage to have it re-chipped wink

Turbo RTs were supposedly all LWB and there was also a couple of 'ltd editions', a Turbo S and a Turbo R Sport, both with the 400bhp version engine IIRC.

Anything is possible but, in all honesty, I would say that the most cost-effective method is to get the model you want from the start.

ingenieur

Original Poster:

4,170 posts

187 months

Saturday 19th March 2022
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Probably right. The Brooklands I'm looking at is a turbocharged later version with supposed 300hp.

In my imagination I'm thinking that would be the same 400hp motor found in the RT but detuned for the Brooklands.

TarquinMX5

2,018 posts

86 months

Saturday 19th March 2022
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I have one book which states that it's possible to increase the Brooklands R to the Turbo R's 400bhp but misses out the crucial information, ie. what's involved. The 400bhp versions used liquid-cooled intercooler, can't recall whether the Brooklands R did.

With the later models running the Zytek ecu and with support for that (other than occasional recon units coming on the market) varying between sketchy and non-existent, and suspecting that the Brooklands and Turbo will be running different set-ups, that might now be a significant factor.

Knowing how much detail RR went into before introducing changes, I doubt it's as simple as different settings on the ecu, but I don't know the complete list of differences. If you're seriously considering it, it might be worth talking to a few specialists (eg P & A Wood, Hanwells) and seeing what they'd quote.

Sorry, can't really answer your question; I've not heard of it being done but that doesn't mean it hasn't been done and I suspect most people would have simply bought a Turbo R in the first place. A Brooklands R is not far off the output of the early Turbo Rs.


Edited by TarquinMX5 on Saturday 19th March 13:02


Edited by TarquinMX5 on Saturday 19th March 13:03

ingenieur

Original Poster:

4,170 posts

187 months

Saturday 19th March 2022
quotequote all
I think if you were going to increase performance you'd want it mappable. So probably a modern ECU with USB connection for laptop.

buyer&seller

793 posts

184 months

Sunday 20th March 2022
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Back in 1998 when I was selling new Rolls and Bentley we had the Brooklands R Mulliner (325BHP also LWB) to sell, our general manager who had a technical background found out that by replacing the ECU plus changing the rear diff it would give the same performance of the Turbo RT, I think the gear knob needed changing too to add the sport mode which the Brooklands didn't have. We did a couple and then someone from Crewe worked out what was being done and stopped the supply of the parts. Sorry I do not have a technical background so can't provide any further details, I just wanted to say that it is possible but I am not much more help than that.

ingenieur

Original Poster:

4,170 posts

187 months

Monday 21st March 2022
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[quote=buyer&seller]Back in 1998 when I was selling new Rolls and Bentley we had the Brooklands R Mulliner (325BHP also LWB) to sell, our general manager who had a technical background found out that by replacing the ECU plus changing the rear diff it would give the same performance of the Turbo RT, I think the gear knob needed changing too to add the sport mode which the Brooklands didn't have. We did a couple and then someone from Crewe worked out what was being done and stopped the supply of the parts. Sorry I do not have a technical background so can't provide any further details, I just wanted to say that it is possible but I am not much more help than that.
[/quote]

That's about what I thought. Didn't think about the rear diff ratio but you could get around to that at some later point if everything else went well.

buyer&seller

793 posts

184 months

Monday 21st March 2022
quotequote all
ingenieur said:
That's about what I thought. Didn't think about the rear diff ratio but you could get around to that at some later point if everything else went well.
From memory the later full turbo cars had traction control fitted so perhaps that's why the diff needed changing, not being a techie sort I don't really know.

alabbasi

2,619 posts

93 months

Monday 21st March 2022
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Brooklands to 96 model years were non turbo charged. The 97 and 98 model year cars came with a light pressure turbo and no air to water intercooler. They made about 320hp. The Turbo R's of those years made 380-400hp. They had an air to water intercooler.

I own several SZ cars and performance difference is notable but not huge. They all have to push around a 6000lbs body.

The Brooklands have some benefits however in that they are much easier to work on. I've been working in replacing o-rings fuel rail o-rings on my 96 Continental R. The job has taken about 4 months and $3000 to replace 4 $2 o-rings that should have never been in the way. If I needed to do the valve cover gaskets, brake pumps etc. It would take the same effort on a later model Turbo R.

The job is much easier on the LPT, even though fuel rail o-rings prove that those cars were built by craftsmen and not engineers. If you're looking at any of the EFI cars and do not see the fuel rail o-rings as a recent job, plan to spend the money to go in there because that job needs to be done so that you don't burn your car down. I've seen too many at insurance auctions that caught fire and I guarantee that this is what failed.


LPT cars also less likely to blow a head gasket which the HPT cars are known to do. They're not cars that you want to boot until they're fully warmed up.

Also consider an early 90's Turbo R from the 92-93 era. These are the cars that have CIS fuel injection which is pretty simple to maintain and the GM 4L80E electronic 4 speed automatic. They make as much power as the LPT Brooklands but without the complexity of the zytec fuel injection.

Edited by alabbasi on Monday 21st March 13:31

ingenieur

Original Poster:

4,170 posts

187 months

Monday 21st March 2022
quotequote all
alabbasi said:
Brooklands to 96 model years were non turbo charged. The 97 and 98 model year cars came with a light pressure turbo and no air to water intercooler. They made about 320hp. The Turbo R's of those years made 380-400hp. They had an air to water intercooler.

I own several SZ cars and performance difference is notable but not huge. They all have to push around a 6000lbs body.

The Brooklands have some benefits however in that they are much easier to work on. I've been working in replacing o-rings fuel rail o-rings on my 96 Continental R. The job has taken about 4 months and $3000 to replace 4 $2 o-rings that should have never been in the way. If I needed to do the valve cover gaskets, brake pumps etc. It would take the same effort on a later model Turbo R.

The job is much easier on the LPT, even though fuel rail o-rings prove that those cars were built by craftsmen and not engineers. If you're looking at any of the EFI cars and do not see the fuel rail o-rings as a recent job, plan to spend the money to go in there because that job needs to be done so that you don't burn your car down. I've seen too many at insurance auctions that caught fire and I guarantee that this is what failed.


LPT cars also less likely to blow a head gasket which the HPT cars are known to do. They're not cars that you want to boot until they're fully warmed up.

Also consider an early 90's Turbo R from the 92-93 era. These are the cars that have CIS fuel injection which is pretty simple to maintain and the GM 4L80E electronic 4 speed automatic. They make as much power as the LPT Brooklands but without the complexity of the zytec fuel injection.

Edited by alabbasi on Monday 21st March 13:31
CIS is far more complex than a computer fuel injection system. I've worked on both kinds extensively. The problem with CIS is if it goes wrong you require a lot of specialist test equipment to sort it. It relies a lot on vacuum pressures, springs and things like bi-metalic strips. All mechanical devices which can only be measured using sensitive mechanical test equipment. Computer controlled injection can often be diagnosed using process of deduction until you find the faulty component and often has diagnosis routines you can plug in a laptop or code reader.

Is the early 4-speed the one where the shifter has moved to the centre console but is right-aligned within the console? Or did they have 4-speed cars with a column change?


Edited by ingenieur on Monday 21st March 13:46

alabbasi

2,619 posts

93 months

Monday 21st March 2022
quotequote all
ingenieur said:
CIS is far more complex than a computer fuel injection system...... Computer controlled injection can often be diagnosed using process of deduction until you find the faulty component and often has diagnosis routines you can plug in a laptop or code reader.
Usually a fuel pressure gauge is what's needed to do diagnostic on a CIS car (if that). No generic scanner will plug into a 90's Bentley and the factory scan tool is about $3000 used.

If the bentley has a floor shifter, it's a 4 speed.

buyer&seller

793 posts

184 months

Monday 21st March 2022
quotequote all
ingenieur said:
Is the early 4-speed the one where the shifter has moved to the centre console but is right-aligned within the console? Or did they have 4-speed cars with a column change?


Edited by ingenieur on Monday 21st March 13:46
The 4 speed was introduced on the 1992 model year, same time as the high level brake light in the rear screen, and the change was on the column, from '93 onwards, when the Brooklands was first introduced, the gear change moved to the centre console.

ingenieur

Original Poster:

4,170 posts

187 months

Monday 21st March 2022
quotequote all
[quote=buyer&seller]
ingenieur said:
Is the early 4-speed the one where the shifter has moved to the centre console but is right-aligned within the console? Or did they have 4-speed cars with a column change?


Edited by ingenieur on Monday 21st March 13:46
The 4 speed was introduced on the 1992 model year, same time as the high level brake light in the rear screen, and the change was on the column, from '93 onwards, when the Brooklands was first introduced, the gear change moved to the centre console.
Interesting... I do like the idea of a column-change. So you're saying some of the column-change cars did have a 4-speed?


Edited by ingenieur on Monday 21st March 15:46

ingenieur

Original Poster:

4,170 posts

187 months

Monday 21st March 2022
quotequote all
alabbasi said:
ingenieur said:
CIS is far more complex than a computer fuel injection system...... Computer controlled injection can often be diagnosed using process of deduction until you find the faulty component and often has diagnosis routines you can plug in a laptop or code reader.
Usually a fuel pressure gauge is what's needed to do diagnostic on a CIS car (if that). No generic scanner will plug into a 90's Bentley and the factory scan tool is about $3000 used.

If the bentley has a floor shifter, it's a 4 speed.
OBD is a standard all manufacturers had to adhere to. So whilst there will be a whole load of parameters which are specific to Bentley diagnostics tools the generic OBD standard must be in the programming as the legislation required it. It's so that emissions systems and other generic things of that nature can be diagnosed by anybody so the cars run clean.

Here's a link for the proper Bosch CIS testing kit, £2396.15: http://www.adesystems.co.uk/garage-equipment/bosch...

alabbasi

2,619 posts

93 months

Monday 21st March 2022
quotequote all
ingenieur said:
OBD is a standard all manufacturers had to adhere to.
Absolutely, you're 100% correct.

buyer&seller

793 posts

184 months

Monday 21st March 2022
quotequote all
ingenieur said:
Interesting... I do like the idea of a column-change. So you're saying some of the column-change cars did have a 4-speed?


Edited by ingenieur on Monday 21st March 15:46
Yes that's right but only the 1992 model year, quite rare as at that time we were in the grip of a recession and Crewe weren't make many cars.

Have a look at the link below, there's loads of information on it including specs, production numbers etc

https://www.rrsilverspirit.com/index2.htm

BenTurboR

18 posts

36 months

Monday 28th March 2022
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ingenieur said:
I thought I wanted a long wheelbase turbo R. Or a turbo RT (they're all long wheelbase?)
Apparently they made two Turbo RT SWBs, one LHD and one RHD.

Out of interest why LWB? Are you going to be driving people around in it a lot? I've not tried the LWB (mine's a '96 SWB example) but I've been told they don't handle as well with the additional length.