Citroën CX 25 GTi Turbo - a rare beast with party tricks | Tyrrell's Classic Workshop

well hello and video I do want to marriage vids for all his help and his inspiration in getting me going with these it was his Espada engine rebuild that started all this and the charting of it and it's funny the comments that people leave there's been a lot of comments about one car in the workshop a very unlikely one you know I'm surrounded by exotica from various countries there and people have asked quite a bit about the Citroen CX GTI turbo this car it is a rare beast and it is an interesting car so I'm going to do a video about it the CX was inspired by various citrons that went before it the DES the sort of that the goddess as it was called the the big luxury saloon that was used by French presidents and people all over the globe really and it's still a very chic and cool car today and the SM the special Maserati as it was called Maserati was owned by Citroen in the late 60s and early 70s and consequently Citroen wanted a flagship model for their sort of to give a halo effect to their model range and they wanted to give Maserati something to do so they came up with the engine for the SM and then Citroen put all their hydraulics in it and one of the features of this car is the very complicated hydraulic system on it and I'm going to go into a little bit of information about how that works but the body was the reason it was called the CX is because in French the drag coefficient of a car which is called CD it's referred to a CD in Britain is CX in French and this car when it was introduced in 1974 I think had a drag coefficient of not 0.36 which is very slippery for a car of the 70s I already came up with a hundred in roundabout 1982 I think and that was CD point three which was incredibly slippery at the time and I already made a big thing about it even put stickers in the windows saying it has a drag coefficient of 0.3 but the CX was citrons flagship model it replaced the SM was a 2+2 it was very cramped in the SM hardly only the backseats the call number +2 is a bit of an insult really but it was a big car as I say a Maserati v6 engine and it had the the hydraulic system which was taken from the DES and developed and the CX almost took the hydraulic system completely from the SM lock stock and barrel over and the CX was quite a commercial success for Citroen but the problem was it was dogged with politics of French car manufacturers in the 1970s there were so many other agendas going on there was in fighting between Citroen and Peugeot and their rivals renault the engine in this car has been basically one engine or two engines right the way throughout its model life one was called the do for our engine a 2.2 liter which were put to one side but the other engine was inherited also from the DS it's a great big two and a half litre 4-cylinder engine and this engine is as strong as an ox if I tell you that I'm very pally with an engine recondition ER who still does a lot of my engine it my machining work etc and in the decades he was in business he never had a Citroen DS engine in for rebuild or a CX petrol engine can you believe that he rebuilt thousands of engines so this is a really really it's it's I think from the 1950s it was written developed it's a pushrod four-cylinder engine as it's called and it's almost sunburst of all and as was the fashion in the 1980s manufacturers wanted cheap high performance so as I say for political reasons they had no choice but to stick with this engine they experimented with a flat six and it was originally one of the original concepts was to put a rankle rotary engine in it that didn't happen because they were still very unreliable in the 70s and there was also talk of a v6 that was produced around that time but no they had to stick with the four-cylinder for cost reasons so what did they do they bolted a turbo on it like everybody else did and this was the result this is an incredibly rare I haven't really focused on it because as I say we've got in my mind more interesting cars here but people have wanted me to talk about it so that's why we're here in turbocharged form it developed 166 brake horsepower which doesn't sound a lot but it wasn't super-heavy lekar it went quite well then the series to which this isn't had the big plastic bumpers and that had an intercooler on it which pushed the power up a bit more the engine on these is very tunable actually because it's so strong you can get horsepower out of it fairly easily more horsepower really and I have adjusted the turbo boost on this just a little bit and it has increased its power to just slightly north of 200 brake horsepower based on previous sort of cars that I've worked on CX is over the years so the power-to-weight ratio is is pretty good really and it has a two or three party tricks this car which I'm going to show you and talk about as we go so let's have a look one of the things that these cars are famous for is the hydropneumatic suspension so they use a a mineral based oil it's bright green and appearance and the advantage of it is it doesn't absorb water so what can happen with conventional brake fluid dot4 as its called and is it can gradually absorb moisture out of the air and it lowers because water boils at 100 degrees C it lowers the boiling point of the brake fluid to the point where it can actually boil and many results as an accident has happened as a result of that but also it's a great good lubricant as well so it helps keep all the Pistons and seals and the braking and the suspension free and I'm just going to start it up now and let's let's see its first if I lower the car on to its lowest setting with this lever on the centre console down we go and this suspension was was quite revolution at the time the D s had it in the 1950s and I put it now put it up onto maximum height and it was you can hear the hydraulic pumps and and valves working in the background the reason one of the reasons why Citroen did this is it helped if somebody lived on a farm or down a lane of something it helped with ground clearance you could actually raise the car to get over humps and bumps and things like that because it's quite a low car and the other advantage is I mean it gave an extremely smooth ride as well but the the other advantage is if you had a flat tire you just put the suspension on high put the jack underneath then put the suspension on low change the wheel put it back on high pull the jack out and you don't have to start messing about with pumping cars up and things like that really really clever so want one other of the party tricks on this car the steering system is called a very power steering system that's what Citroen called it it was introduced on the s/m in in its form in this and the steering wheel the steering column behind the dashboard here is actually a great big hydraulic unit with lots of valves and things on it and it's got a cam so that the steering self centers which pushes down on the steering column as it revolves so with the hydraulic pressure I can turn the steering wheel like that and it always returns to the centre position even if I'm not touching it and it doesn't do the front tires a lot of good with all that weight on them from the engine and everything but it's quite it's quite useful because on the road if the steering setup properly the car trucks dead straight absolutely dead straight so I'll just go into a little bit more detail about the suspension now well what makes all this happen what's the the heart of this system really it's a pump tiny pump that's driven by the engine a swashplate pump as it's called with seven tiny Pistons inside it and it's driven by a fan belt from the engine can you believe it but it does have redundant systems built in so if you break down you don't suddenly lose your brakes but eventually you would a new suspension but it worked okay so it's not fantastically pure engineering but it did work but otherwise this system is sort of a work of genius the the pump pressurizes the what's called the redundant system so the whole of the car is pre pressurized to between 180 and 200 bars around about 2200 to 2600 pounds per square inch a lot of pressure just from that little pump and when you press the brake pedal what you're doing is actually just releasing some of that pressure to the calipers on the wheels so the pressure is always there and it turns into kinetic energy when you press the brake pedal and the these spheres here are what control the suspension itself apart from the ride height the actual way the car rides and the legendary Citroen sort a magic carpet ride is controlled by these and these are so clever and I've got one here and this is the suspension sphere and it's got a diaphragm in here this end is pressurized with nitrogen to 75 bar thousand psi so the the diaphragm is obviously pushed right up against this end of the sphere and as this pump pumps the car up the suspension up fluid comes into the sphere and actually pushes down on a piston and it raises the car to whatever height or lowers it again but the really clever thing about this is the cars got no shock absorbers because it doesn't need them inside here is a tiny hole drilled to a precise diameter and that's the shock absorber for the whole corner of the car because what happens is it acts as a restriction for the fluid passing in and out of the sphere as it goes over a bump the fluid transfers from down here into the sphere and back and that the size of that venturi the size of that hole dictates how stiff the suspension is so the smaller the hole the less fluid can try through the stiffer at the rider's bigger the whole smooth of the ride so simple and Citroen used this system for years and because the car had height adjustable suspension it was actually outlawed in the u.s. in 1974 which is why Citroen couldn't export it to the US but this makes the system what it is it's so clever another byproduct of that is on the the estate version of this car the safaris it's called which had a legendary load capacity a very very big load carrying capability the pressure on the back brakes was actually altered by the pressure on the suspension so the whole thing compensated for itself to stop the back wheels skidding and locking up I mean just so clever and one of the other aspects of this is that I mentioned earlier about the very power steering system to my knowledge these are the only cars where the steering wheel isn't connected to the front wheels directly you move the steering wheel you're triggering a hydraulic sensor in the steering column which moves hydraulics on the steering rack remotely through a pipe so while you're driving this you're not actually technically connected to the front wheels and there is a redundant system as it's called so if the hydraulics do go again there's a very basic steering column goes from the steering wheel to the right but it's normally not used the whole thing is done remote it's it's a remote control steering system so we're going to take the car on the road now and give it a run and we'll see another of its little party tricks another of the the great aspect of this car is the is the smooth ride it is it is sort of like riding on a magic carpet a little bit the the GTI turbo version such as this one they did firm up the ride a bit and they also put thicker anti-roll bars on which also affect the ride but it's still very smooth you sort of glide along the road its effortless really and the suspension system Citroen first use it on the traction of are in 1954 I think just before the D s came out the front that the traction of arm was the the revolutionary front-wheel drive car that sort of set the template for a lot of modern cars front-wheel drive and front engined but the rolls-royce used the system on the silver shadow that came out in 1965-66 and they actually had to pay Citroen royalties for using the concept Davi the high pressure pump braking and suspension system although those were driven from pumps off the engine off the camshaft actually in the engine not via fan belt as the Citroen ones were a Mercedes used a virtual carbon copy of this system on the 450sel 6.9 in 1975-76 and mercedes didn't pay royalties to Citroen and the system is almost identical but I can't imagine there's many car manufacturers that Mercedes imitate or pinched ideas from but they certainly did on this occasion and one thing I'm going to show you now is the other party trick when you accelerate in this car and because of the design of the suspension it almost feels like a jet plane taking off the back sinks and you get this sort of washing feeling because like all 80s cars the turbo there's like there we go whoop there she goes and if I take my foot off the whole thing just comes back up again it's like a really weird aircraft taking off sensation and these cars are deceptively quick they really are they they were quite a credible car in their day probably the closest rival they had was the the rover sd1 Vitesse which was itself a very underrated car and a similar story to this really with the rover company politics British Leyland was going through terrible troubles in the late 70s and the st1 was a great car but it never really got its day so I'm gonna just try that again we'll turn around and just try the back suspension dipping under acceleration it's a really great feeling a little bit unusual [Music] it's often interesting to know where the the history of brand logo has come from and car manufactures are no exception at the the Citroen logo is is called the double Chevron the reason why it was called this these are gears off a lamborghini miura that we got infrared serration but andre citroen actually bought the world patent for double Chevron gears and he started off as a precision engineer as a gear manufacturer and the double Chevron gears double helix gears spur gears sort of lined up like that side by side and that's why we have the logo that was what he was first known for and what he was initially made his career out of really so yeah just an interesting facet of Citroen history well that concludes another Turrell's classy workshop video I hope you've enjoyed it if you do like it please like please share please subscribe and we'll see you again soon with something a little bit different again goodbye

Channel: Tyrrell's Classic Workshop

Views: 243,708

Rating: 4.9806623 out of 5

Keywords: Iain Tyrrell, Tyrrell's Classic Workshop, Classic Car Expert, Classic Car Restoration, Classic Car Insights, Classic Cars Cheshire, Citroën, Citroen, CX 25 GTi Turbo, CX25, Hydraulics, hydropneumatic suspension, low drag coefficient

Id: LMh1AlIbbs4

Length: 17min 40sec (1060 seconds)

Published: Sat Apr 04 2020