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Porsche 951

car to love

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Peter Seymour-Howell11/05/2021 22:03:36
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Hi Tim and Jason, my apologies chaps, you are of course, correct which is a bit worrying for me as clearly my mind is worse than I thought? That's another story which I don't want to bore you guys with my health issues.

I have just reread my notes and yes I did state that it's the CR that is affected not displacement...sorry about that and thanks for putting me straight.

Pete

Steviegtr11/05/2021 22:07:27
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Peter as promised , put a few of my past cars in my cars album.

Steve.

Peter Seymour-Howell11/05/2021 22:26:48
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Posted by Steviegtr on 11/05/2021 22:07:27:

Peter as promised , put a few of my past cars in my cars album.

Steve.

Thanks Steve... I saw them...didn't know how to acknowledge.. should have just said so here..lovely cars.. I'm intrigued..what's the story with the Tesla?

Steviegtr12/05/2021 00:59:18
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It's a guy on youtube who buy's write off tesla's. He then makes other cars electric. That one was at Copart, i might say a place where i have bought over 100 motorcycles & scooters to repair. Plus quite a few cars & camper vans. I digress. He was at Copart looking round & came across that one. What i never knew was the whole floorpan is the battery store. Thousands of them. The whole lot had gone up in smoke. I believe the early batteries used were terrible for catching fire.

Steve.

Russell Eberhardt12/05/2021 09:49:54
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Posted by Peter Seymour-Howell on 11/05/2021 18:34:30:

One of the secret weapons on this engine, the two balance shafts that give this big 4 pot the same smooth running as a straight 6.

 

Not much of a secret. Lanchester used that idea back in the 1930s they even used it with the shafts geared up to remove vibration harmonics on six cylinder engines.

Russell

Edited By Russell Eberhardt on 12/05/2021 10:03:46

Peter Seymour-Howell12/05/2021 10:28:54
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Posted by Steviegtr on 12/05/2021 00:59:18:

It's a guy on youtube who buy's write off tesla's. He then makes other cars electric. That one was at Copart, i might say a place where i have bought over 100 motorcycles & scooters to repair. Plus quite a few cars & camper vans. I digress. He was at Copart looking round & came across that one. What i never knew was the whole floorpan is the battery store. Thousands of them. The whole lot had gone up in smoke. I believe the early batteries used were terrible for catching fire.

Steve.

Ah.. yes electricity, has its own issues, safety is one although perhaps not as bad/often as fuel. EV's are the future, there's a video on YT of a guy who's converted his IIRC 951 (could be a normal 944?) to electric and then put it up against the latest McClaren on the dragstrip. Well, let's just say that not only did the 944 win but evidently it won by a bigger margin than any car before it against this brand new McClaren. I don't think that we will see the end of IC engines though, certainly not Porsche who have teamed up with Siemens to produce their own zero-emissions fuel to keep all old Porsche's on the road. IIRC they will be testing it either later this year or early next and have invested other £1 billion into new factories/plants to produce this new fuel.

They are also very much into electric and again have joined a partner (can't recall who although could be Seimens again) for electric flying cars which on being developed as we speak.

Pete

Pete

Peter Seymour-Howell12/05/2021 10:32:01
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Posted by Russell Eberhardt on 12/05/2021 09:49:54:
Posted by Peter Seymour-Howell on 11/05/2021 18:34:30:

One of the secret weapons on this engine, the two balance shafts that give this big 4 pot the same smooth running as a straight 6.

Not much of a secret. Lanchester used that idea back in the 1930s they even used it with the shafts geared up to remove vibration harmonics on six cylinder engines.

Russell

Edited By Russell Eberhardt on 12/05/2021 10:03:46

True, sorry I didn't mean 'secret' per se, just that not many people know of this feature and it does mean that the engine can be pushed far more than most others. IIRC Porsche paid royalties to Mishibusi who held the patent at that time?

Pete

Steviegtr13/05/2021 02:15:24
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Hi Pete. some of the bhp figures you have given are extreme. Are you sure of these figures. We can all say our cars have this much power, but is it real. The Skyline i had was already very powerful when i imported it from Japan with 1000cc injectors, a forged & balanced crank to 9000rpm & twin turbo's with steel impellors & 360degrre cut back blades. The bearings were roller with oil & water cooling. This with a lot of electronics & high octane fuel gave around 700 BHP. This was using a RB 26 DET block with strengthened main bearings. The most powerful 2.0 cosworth engines were good for around 450 bhp with a lot of work. The Colins & Routh motors with the 2.4 litre conversion could reach around 600 unreliable bhp.

Steve.

Steviegtr13/05/2021 02:38:06
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a recorded 174mph on one of my trips to Le Mans, back then she only had 282 bhp...recorded by sat nav, not my speedo which at the time was bouncing off its 170 mph pin and still accelerating hard until the column of cars backed off a little...

Pete although i have done the Le-mans trips many times myself, in A Bentley arnage black edition. A Bentley arnarge red edition A few Tvr variants. A 911 Turbo . A 993 RS. . It would be impossible to record 174 mph from 282 bhp. Do the math. My skyline registered 193mph at Elvington in 1998. That was with 700 BHP. I think your figures are maybe just what you think they were. Not actual. I ran a 9.8 sec 1/4 at Melbourne raceway in 1999. I have the ticket. But the point is a Nissan Skyline can be tuned to over 1000bhp. I do not think an old 944 2.5 inline 4 could ever be that good. I wish you were right but it's only a pipe dream . Even my old Ultima gtr with the 350 ci ls6 engine could only manage 182 down the Mulsane straight. Sorry.

Steve.

Jon Lawes13/05/2021 05:25:02
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556 forum posts

StevieGTR,

There are more figures to consider here, such as gearing, co-efficient of drag, weight, and distance you had available. Air density would affect both aerodynamics and efficiency of intercooling and the temperature of the air charge. Wind direction, gradient, tyre pressures, ground clearance, underfloor aerodynamics, following another vehicle and making use of its slipstream. An autobahn is longer than Elvington. Your skyline had (assuming it was the GTR and not a GTS or similar) an additional gearbox, propshaft and drive shafts to spin, presumably fatter rubber, so lots of additional parasitic drag as you are obviously aware. You are obviously aware of these factors as you are a petrolhead from your previously owned cars.

There are certainly enough variables that I wouldn't be decrying the integrity of another forum member.

Edited By Jon Lawes on 13/05/2021 05:25:34

Peter Seymour-Howell13/05/2021 05:49:29
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hi Steve

Pretty much so although the Cossie hasn't been on the dyno yet, the work has been done by a top outfit or so I'm told, I'm not into Ford's these days so a little out of touch.

As for my own car, very confident in the figures given, I used to be very much involved in the 944 Turbo UK league. Details can still be found on google, back then the car was the 5th most powerful in the league, this was at only 368bhp, the top car being over 400, figures that were proved numerous times on a number of rolling road sessions across the country. Such sessions were closely monitored for the accurate shoot-out setting to ensure we always had factual figures, it's very easy to trick rolling roads. This is going back nearly 15 years and the car has been developed a hell of a lot further since. The last round of upgrades cost over £12k in parts alone, machining is done by Serdi UK. Compared to the guys in the US, my car is only mildly tuned, there are plenty of YT vids with details..

174mph with 282bhp, easy...a few things to note, the 951 came in two guises, the 220bhp with Porsche stats giving it a top speed of 152 and the 250bhp with stats at 162. Now Porsche always gives lower figures than a car actually does, for example, all road tests of the day achieved higher performance figures in both acceleration and top speed, the 220 coming in at 159mph. Ok, so we need to note a few things about Porsche, from day one they did all they could to keep the 951 slower than the 911, at the time they said this was to make the car easier to drive, to do this the boost was allowed to leak long before the car actually hits max boost (which btw was 0.75 and 0.82 bar for the two variants) and the engine was never allowed to hit the redline in higher gears, this is a fact. Even after this attempt by Porsche they themselves admitted in the late '80s, early 90's that the 951 was the fastest car in the fleet, this included the 911 turbo. With A DPW fitted, this alone changes everything and allows a red line in all gears, even without extra power the car will be much faster.

end part 1

Peter Seymour-Howell13/05/2021 05:50:25
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part 2

The 951 has very long legs, as stated before there are cars in the US with approx 500bhp that have recorded 200mph, as for that matter have cossie Saph's, IIRC at Brungtindon,, sorry can't recall the name of the runway. These things were published in one of the Ford mags a few years back.

Back to the 951, BTW there is a video on YT of a 280 PS 951 doing the ring in just over 8 secs..an impressive bit of driving and at 280, barely tuned. The 174 trip was in a column of cars, a number of which had Sat nav, these are where the speed was recorded, as I said my speedo being the early car maxed out at 170, later cars was 180. The speedo in these cars is out by 6mph from 40mph all the way to max, this has been checked a number of times but as I said, my speedo was bouncing off its pin at the time anyway so not what was used.

I year or so back I had a short run-in with an Audi RS, I never stay at high speed so just play for a few seconds, actually, the last such game was with a new GT3, I had observed him coming up fast in the outside lane, I didn't know it was a GT3 at the time, just that it was a new 911. I waited for his approach, I was doing 95 in fourth, the 951's sweet spot, as he got close I noted he booted it as the car squatted, probably trying to show how good his car was. I waited until he was just about to disappear from my door mirror and then increased power, this was for a few brief seconds only, He got as far as my front wing before my car hit boost and shot past him at over 140 mph at which point I had made my point and backed off. It was only when he passed that I noted the GT3, but then having watched 951's in standard form beat brand new GT3's on the race circuit for some years it didn't surprise me.. BTW, on checking my data log I only actually used 65% throttle, good job the poor GT3 owner wasn't aware of that little fact... I digress,, back to the RS, doing a similar thing to the GT3 but in this case, I missed a gear, not a big deal as I can easily catch but it's what the data log showed and later entered into gear calc that was interesting. I hit 92% throttle, I never rev the engine that high even if it has been designed to do so, max rpm was 7134, this equates to 196mph with the final drive and tyre sizes entered into gear calc, so yes I believe the chaps in the US who have recorded more than 200mph.

The other thing to bear in mind about these cars is they are just as planted on the road at max speed as they are while cruising, something a 911 owner noted while a passenger in my car at 130mph, he couldn't believe the speed due to how solid the car felt, something his own 993 C4 could never do. The aerodynamics of the 951 is leap years ahead of its time, for example, the rear diffuser was the first for any car and is patented for it, this is before such things appeared in F1. IIRC it produces 25kg at 50 mph, ok, not even close to something like the Ferrari F50 but I think you get my point?

There are very few cars on the road in any form that can compete with a well-sorted 951, its handling is supreme and recognised so by those who were involved with racing development in Porsche, giving the early car the highest praise, but then the 951 was a race car before it was a road ca and as I think I pointed out, is a registered Group B race car. It truly is a one of a kind type of car, a very special car and I know many Porsche enthusiasts who have sold their 951 in search of the iconic 911 only to regret it and either sell the 911 for another 951 or own both. When challenged to which is the best though, it's nearly always the 951.

Anyway, that's enough rambling from me, lets just say that I am very confident in the car's ability, it's just after 5:30 am here and I should be asleep..

Cheers

Pete

Peter Seymour-Howell13/05/2021 06:07:00
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Posted by Jon Lawes on 13/05/2021 05:25:02:

StevieGTR,

There are more figures to consider here, such as gearing, co-efficient of drag, weight, and distance you had available. Air density would affect both aerodynamics and efficiency of intercooling and the temperature of the air charge. Wind direction, gradient, tyre pressures, ground clearance, underfloor aerodynamics, following another vehicle and making use of its slipstream. An autobahn is longer than Elvington. Your skyline had (assuming it was the GTR and not a GTS or similar) an additional gearbox, propshaft and drive shafts to spin, presumably fatter rubber, so lots of additional parasitic drag as you are obviously aware. You are obviously aware of these factors as you are a petrolhead from your previously owned cars.

There are certainly enough variables that I wouldn't be decrying the integrity of another forum member.

Edited By Jon Lawes on 13/05/2021 05:25:34

Thanks, John, you just brought up a few points something which I had forgotten...there is no prop shaft on the 951, it has a torque tube which is a direct link between the engine in the front and gearbox (transaxle) in the rear, power loss through geartrain is mush less, yes it loses some through the drive shafts but not a lot. My car is much lower than standard, more than 30mm lower, the staggered tyre setup I have kept at original sizes, bigger tyres generally mean less performance, although they are now the highest speed rating available.

Cheers

Pete

Peter Seymour-Howell13/05/2021 06:13:03
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hmm.. not sure what happened to the text size in my last reply, sorry about that, hope tis one is better?.. I also forgot underbody aero panels.. the 951 is covered in them which are not only designed to affect downforce but also to direct the lowest pressure of air through the intercooler, the air literally gets sucked in due to the front shape and the underbody panels around the engine.

Pete

Peter Seymour-Howell13/05/2021 06:31:35
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I was sitting here thinking how can I show just how good a 951 really is as I know many don't believe it until they actually get behind the wheel. So here's the YT vid I mentioned of the 951 with just 280PS, well he says 270-280 , this is with road tyres and from a guy who learnt the circuit on a PlayStation?.....I have no idea of his driving experience, he's clearly switched on if a little mad... but then he's driving a car that can be trusted, you feel when it's near the limit and it's an easy car to correct when required, not something that most other cars can do in similar circumstances.

https://www.youtube.com/watch?v=_85099hlExA

Tim Stevens13/05/2021 15:45:47
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1430 forum posts

Readers might like to think about a rear-drive car with a torque tube but no prop shaft inside it, resulting in much less power loss. The age of miracles is not dead, indeed.

Regards, Tim

Steviegtr13/05/2021 16:01:37
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Posted by Tim Stevens on 13/05/2021 15:45:47:

Readers might like to think about a rear-drive car with a torque tube but no prop shaft inside it, resulting in much less power loss. The age of miracles is not dead, indeed.

Regards, Tim

Tim there is a propshaft inside the torque tube. Connected at the engine end with the clutch. The rear being a transaxle layout. Still the friction, just a nice layout.

Steve.

Samsaranda13/05/2021 17:38:02
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I am afraid that the “mystique “ of Porsche cars is lost on me, my son in law owned a 924 and one day I got a phone call from him, he had broken his arm which was in plaster, could I meet him and drive the Porsche home and keep it my garage. I was distinctly unimpressed with the drive home, I found the car very uncomfortable and the ride harsh, maybe I missed something or the car was a bad example, I grant it was at the bargain end of Porsches but it didn’t meet my expectations. If you really want to frighten yourselves then a number of circuits on a real racetrack in an Atom does it for me. Dave W

Michael Gilligan13/05/2021 17:51:57
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Posted by Peter Seymour-Howell on 13/05/2021 06:13:03:

hmm.. not sure what happened to the text size in my last reply, sorry about that […]

.

It’s very mundane compared with the car stories, but here goes:

You were replying to Jon ... But you did so within your quotation of his post, instead of below it.

The final part of Jon’s post was an Edit, which the forum puts in a smaller font

... and that formatting is carried over to what you are writing.

MichaelG.

Peter Seymour-Howell13/05/2021 18:18:47
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hmm.. guys.. the shaft does not have the Uj's as found on a car with a prop shaft, hence it loses less power than a car with a prop shaft.. The shaft is also lighter and thus less rolling mass. NO play from the U/J's and lighter makes a big difference on power loss from the engine to gearbox and thus to wheels It's years since I've played around with prop shafts but IIRC they are pretty heavy and large in diameter, 2, perhaps 3 inches? The solid shaft on the transaxle cars is only 1" diameter, ok it sits in a pretty substantial tube but that is not part of the turning mass, a lot of power is lost through a U/J.

BTW this tube adds a lot of strength/rigidity to the chassis, for example, you could remove the body and the rest of the components would remain upright just as with cars with separate chassis and body., it's also a huge safety factor, again IIRC back in the 80's the EU NCAP tried to enforce stricter safety rules in how high a speed, occupants in a car must be able to survive in a head-on crash. Today tests are performed at a speed of 50kph, the 951 was designed for people to be able to survive a head-on crash above 60 mph, nearly twice the speed of tests performed today. IIRC, only two vehicles ever passed this test before it was dropped as too ridiculous a requirement to put on manufactures. Before this was dropped only two cars passed this stricter test, the 944/951 and I believe the Renault 5 turbo, coincidentally both Homologated as Group B race cars.. This particular feature of the car is fairly new to me so please forgive me if I have any of this incorrect, I don't have the notes in front of me.

I know people who have been involved in very high-speed head-on crashes in a 951 and walk away with little injury, try doing that in any other car from any other period. The secret of the design is the torque tube casing having substantial steel claws which in a crash, grip the chassis tunnel and thus helping to stop the cabin from being squashed in a head-on crash, simple but clearly effective.

Regards

Pete.

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