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Pics look good! I’m really looking forward to seeing the full build!
I noticed you are going to run the rear WRC cradle. I never paid much attention to it, but the bump steer on that might actually be worse than on a 6 degree beam. Fixing it would be quite simple though. I really can’t understand how Ford got it that wrong on the WRC.
These are the problems you get when you copy a design that was not that good to begin with. Ford were constrained in the 90's to the original pickup points. These cradles are just copies of that design adapted to fit other cars. That design needs longer lateral arms rather than sticking with the short ones. The mounting points for the arms need to be adjustable too. On mine the rose joints practically touch in the middle. You are right though about being worse that the 6 degree beam. So much go go wrong on the geometry. I hope the OP can get the geo right on it, all this time for something that could have been totally bespoke and to the absolute best of designs, instead it ends up with a 1990's Ford cradle in it
Sorry Caddyshack but after what you have been through with this I expected better than that.
I am no chassis expert. We have made sure that the links are equal length and parallel to each other. My track is narrower than a 6 degree but not by much. The car used to squat a lot under acceleration on a std beam and the 6 degree really improved that...it also had 1992 aged rubbish shox and incorrect springs. The suspension pick up points both ends were slightly out and in poor and weak positions. This is a shell design of a fwd hot hatch that was coming to the end of production in 1994 and someone shoehorned in a 4x4 Cossie and more than 3 - 4 times the power.
The shell is now going to be much stronger with better location of suspension and we can measure the bump steer I assume by making the wheel travel right through it's arc. I can then get the chassis guru's to set it up as best as possible for what I will use it for. There is a lot more adjustment in the chassis set up now so I expect I can get a reasonable set up.
I am confident that it will be better now than it was and even with the compromises listed above it was a weapon before.
Whilst people refer to the cradle as WRC it would not actually bolt in to a WRC Escort, it is different.
I did not follow that much of the WRC but I think the Escorts were different to the Sierra although the Escort had a Sierra floor plan IIRC, If my car handles as well as a WRC Escort that won some WRC rallies then I will be happy with that...I do not think the WRC boys have anything to fear from me taking their crowns.
I do not have any design input or suspension analysis of my cradle to compare to the WRC cars, I assume that there is something around showing that the WRC cars did actually bump steer or is it just one of those "known" things I wonder?
My cradle is made of Light weight T45 and has the supra diff mounting points so I am confident it is one of the lightest solutions out there, certianly lighter than WRC cradle or 6 degree beam.
Just found this: Seems Xsport did some testing on a true WRC cradled care (Fulla)
Stuart Day, runs Performance Cars at Popham, near Basingstoke, and knows a thing or two about high performance cars, especially Fords, and Cosworth Escorts in particular. Stuart has had a craving to own a World Rally Car spec Escort, having owned 11 Cosworth badged Fords over the years he reckons the Escort WRC version is the top of the tree. His current car was first built by none other than M-Sport under the guidance of Malcolm Wilson. It ended it WRC career was converted to right hand drive and painted bright red at DOME Motorsport, did a bit more privateer rallying and was then bought by Stuart as a trimmed shell.
The car was re-equipped with all the WRC spec parts that it should have and it took to the track. This is when the problems started... Rally cars, no matter how good they may be in the forest or on a tarmac stage, are just not built the same way as a proper race car. They have loads of suspension travel, and often upsetting bumpsteer designed in to unsettle the car leaving the driver to skilfully deal with the unexpected road conditions and changes in direction typical of a rally stage. Circuit racing is not so unexpected, each lap being similar to the previous one! What is needed is grip, and predictable grip at a far higher level than any rally car can provide.
A few more test days with some trial and error mods didn’t provide the answer, and a frustrated Stuart was looking for a solution, seeking advice from a number of sources. Some damper work found a small improvement, and a full car alignment gave another step in the right direction, making the car a bit more user friendly near the limit of adhesion. Then Stuart was pointed in our direction by John Cross of Cross Sport in Basingstoke. We have completed three race car projects with John now, so he is a useful ally.
Stuart asked us to have a quick look over the car and see if we could offer any help. Back at his Popham workshop we put it up on the ramp, and as the body was lifted on the wheel free ramp, the massive rear bump steer gave us some clues! The car is the full WRC spec and so has struts all round, not the normal rear end semi-trailing arms. Great for travel and jumping of Finland’s forest tracks, not so good for Brands Hatch’s smoother demands. However the suspension parts are very strong and well engineered, just in need of different parameters.
We did the full 3D suspension survey and provided a report with as much detail as possible about what the problems were and how to fix them. Stuart did everything that we advised, re-rated and shortened the Reiger dampers, moved suspension pick-up points, altered anti-roll bars... the lot. Then with a fresh 700bhp engine in place a test day was taken on. Initial results were impressive, the “lively” rear end was now planted, no wheel spin, just forward acceleration, and such lateral grip that my joke up front that he should be careful he didn’t smack his helmet on the driver’s side window as the turn-in would be impressive, turned into a reality as he did just that!
I hope it is ok to quote the article here.
Other than the location points (mine are different) it would seem that the bump steer may also be over a long travel, I doubt mine will experience such extremes of travel anyway.
I don't mind a lively rear on track, my last track car was an early 911.
Last edited by Caddyshack; 09-10-2019 at 03:53 PM.
That’s a nice article and proves the WRC rear end is not that good. But I can’t see it being any good on a rally car either. I would expect you want grip and predictable behaviour on a rally car as well. And in the 1998 WRC season the Escort WRC was not very successful against the Impreza, Lancer EVO and Corolla.
These are the problems you get when you copy a design that was not that good to begin with. Ford were constrained in the 90's to the original pickup points. These cradles are just copies of that design adapted to fit other cars. That design needs longer lateral arms rather than sticking with the short ones. The mounting points for the arms need to be adjustable too. On mine the rose joints practically touch in the middle. You are right though about being worse that the 6 degree beam. So much go go wrong on the geometry. I hope the OP can get the geo right on it, all this time for something that could have been totally bespoke and to the absolute best of designs, instead it ends up with a 1990's Ford cradle in it
Sorry Caddyshack but after what you have been through with this I expected better than that.
Why would you want to have such long suspension arms? That way there is hardly any camber gain in the corners.
End of the day I don’t think it matters what mark dose it will never be good enough for passionford lol and I think Toby is after a fast road weekend toy and the odd track day. Not a world class wrc spec car lol. I’m 99% sure once mot’ed and he declares it pretty much done it will be an absolute weapon that will drive away from most things on 2 or 4 wheels that try it on lol
Just found this: Seems Xsport did some testing on a true WRC cradled care (Fulla)
Stuart Day, runs Performance Cars at Popham, near Basingstoke, and knows a thing or two about high performance cars, especially Fords, and Cosworth Escorts in particular. Stuart has had a craving to own a World Rally Car spec Escort, having owned 11 Cosworth badged Fords over the years he reckons the Escort WRC version is the top of the tree. His current car was first built by none other than M-Sport under the guidance of Malcolm Wilson. It ended it WRC career was converted to right hand drive and painted bright red at DOME Motorsport, did a bit more privateer rallying and was then bought by Stuart as a trimmed shell.
The car was re-equipped with all the WRC spec parts that it should have and it took to the track. This is when the problems started... Rally cars, no matter how good they may be in the forest or on a tarmac stage, are just not built the same way as a proper race car. They have loads of suspension travel, and often upsetting bumpsteer designed in to unsettle the car leaving the driver to skilfully deal with the unexpected road conditions and changes in direction typical of a rally stage. Circuit racing is not so unexpected, each lap being similar to the previous one! What is needed is grip, and predictable grip at a far higher level than any rally car can provide.
A few more test days with some trial and error mods didn’t provide the answer, and a frustrated Stuart was looking for a solution, seeking advice from a number of sources. Some damper work found a small improvement, and a full car alignment gave another step in the right direction, making the car a bit more user friendly near the limit of adhesion. Then Stuart was pointed in our direction by John Cross of Cross Sport in Basingstoke. We have completed three race car projects with John now, so he is a useful ally.
Stuart asked us to have a quick look over the car and see if we could offer any help. Back at his Popham workshop we put it up on the ramp, and as the body was lifted on the wheel free ramp, the massive rear bump steer gave us some clues! The car is the full WRC spec and so has struts all round, not the normal rear end semi-trailing arms. Great for travel and jumping of Finland’s forest tracks, not so good for Brands Hatch’s smoother demands. However the suspension parts are very strong and well engineered, just in need of different parameters.
We did the full 3D suspension survey and provided a report with as much detail as possible about what the problems were and how to fix them. Stuart did everything that we advised, re-rated and shortened the Reiger dampers, moved suspension pick-up points, altered anti-roll bars... the lot. Then with a fresh 700bhp engine in place a test day was taken on. Initial results were impressive, the “lively” rear end was now planted, no wheel spin, just forward acceleration, and such lateral grip that my joke up front that he should be careful he didn’t smack his helmet on the driver’s side window as the turn-in would be impressive, turned into a reality as he did just that!
I hope it is ok to quote the article here.
Other than the location points (mine are different) it would seem that the bump steer may also be over a long travel, I doubt mine will experience such extremes of travel anyway.
I don't mind a lively rear on track, my last track car was an early 911.
Stu’s car is a very very serious bit of kit. All the talking aside that thing is a fast track car. And he can drive it. Can’t wait to see yours done the time effort and detail in it make it a very very high spec car. Lots talk the game but very few will actually build something like you are fair play
I don’t claim to know anything about the WRC back end but one thing you’r are all missing is the AG motorsport focus has the wrc back end and that thing is pretty unstoppable on track
I don’t claim to know anything about the WRC back end but one thing you’r are all missing is the AG motorsport focus has the wrc back end and that thing is pretty unstoppable on track
It wasn't/isn't a WRC back end. It is Andy's own design that removed the flaws of the factory 1995+problems.
I don’t claim to know anything about the WRC back end but one thing you’r are all missing is the AG motorsport focus has the wrc back end and that thing is pretty unstoppable on track
AG focus does not run WRC back end, its all Bespoke
Surely if the link bars are equal length and both pick up points on the cradle are 100% in line with each other and then the same at the hub end where would the geo change come in under bump or sag? I cannot see that unequal spacing between the rods makes any difference at the cradle end as the rods remain same length through travel.
The early WRC cradles, I believe, had unequal rod lengths due to different pick up points.
The toe link WILL move the wheel back and forwards a little through travel as that arc changes but that would not steer the rear wheel as the 2 connecting rods hold the wheel square...unless the wheel moving due to the tow link changes the effective length of the 2 link bars thus creating bump steer?
I will need to make a lego model and move it around.
I have asked Mark to get a camber, castor and bump steer gauge and move my suspension through bump and sag and show how many thou or mm the laser moves through the expected tarmac usage.
I will post some cradle pics up later
Last edited by Caddyshack; 10-10-2019 at 12:16 PM.
Yes, the more I play it through in my mind it can only really be that. It will be interesting to see if and how much my one moves, Mark will send me a video and the measurements.
i have been researching a few cradles and it seems all are based on the Wrc design but with some improvements.
AG one which according to AG, if I am right is a copy of the Escort WRC cradle with a few mods. Is this the focus? Is this Marc Kinsey? Also AG? Pretty much the same as mine and a rough copy of Wrc with some improvements. My one. Is this one Mark K’s? I think this may be AG as well with double length links due to wider track and better travel for gravel. Still a copy of Wrc concept and the toe link would still move the wheel probably which would still have a bump effect, I guess? The bottom of the hub looks wider, I assume this is more "leverage" for slicks?
Where were all the experts at the start of the project?
I know nothing about suspension geometry but think it will be fine and a massive improvement over the cabodgitation you had before, it’s not like your chasing tenths of a second on lap times.
Where were all the experts at the start of the project?
I know nothing about suspension geometry but think it will be fine and a massive improvement over the cabodgitation you had before, it’s not like your chasing tenths of a second on lap times.
I think it will be mega and as you say a huge improvement.
My cradle is pretty bespoke to be fair, it is made for quick change supra diff, t45 light weight, it would not fit a Wrc shell and has different length arms and is made to my 205 track. I suspect it will be over the top for the use i will have for it....few track days, maybe a couple of drag strip runs, poss hill climb and mainly a and B road blasts.
....and one very talented driver :-0.
Last edited by Caddyshack; 10-10-2019 at 04:53 PM.
My 106 was done same as AG focus, anyway it is what it is now as its all in place so cant be changed but for what you intend on using it for i'm sure will be more than up to the job....... so get the car back and get it progressed, its been far far too long now.
My 106 was done same as AG focus, anyway it is what it is now as its all in place so cant be changed but for what you intend on using it for i'm sure will be more than up to the job....... so get the car back and get it progressed, its been far far too long now.
Thanks. Did you find anything problematic with the 106 handling on road?
Don't get me wrong, I think it is awesome what you are doing! I wish I could fit such a suspension to my car. If done right it must be a huge improvement, both in geometry and in unsprung weight. But that is the important but difficult thing, getting it right.
BTW, I don't think that the longer arms are actually better for your use. The longer arms give hardly any camber gain during cornering. For a gravel car this is nice, you don't want to have much camber anyway, but you do want a lot of suspension travel. For a track car it is different though, you don't have much suspension travel but you do want a lot of camber gain in the corners. I believe that is also why a double A-arm is better than a McPherson setup.
I agree, I see people wind in loads of negative camber on road cars thinking it is a good thing, you should see the ones on the TT Forum I go on.
I struggled to dial in the car before as there was not enough room to adjust the beam the way the conversion had been done, now that problem has gone away.
I expect this car will be capable way beyond my talents and I doubt many would get out of a proper WRC car and think their talent was beyond the chassis.
I'm not sure if I agree with you on the talent vs. car question. For instance the old Porsche 911 is known as a very tricky car and a lot of people would probably end up in a tree with it. I think it takes a lot more talent to drive such a car fast. So from that point of view a very good car can be driven very fast by a not so great driver. On the other hand a great car might be a bit boring to drive compared to something less good.
A few days ago I came across this youtube video of Carfection driving the '97 Impreza WRC of Colin McRae. If you see how that corners, it must be awesome to drive!
I'm not sure if I agree with you on the talent vs. car question. For instance the old Porsche 911 is known as a very tricky car and a lot of people would probably end up in a tree with it. I think it takes a lot more talent to drive such a car fast. So from that point of view a very good car can be driven very fast by a not so great driver. On the other hand a great car might be a bit boring to drive compared to something less good.
A few days ago I came across this youtube video of Carfection driving the '97 Impreza WRC of Colin McRae. If you see how that corners, it must be awesome to drive! https://youtu.be/eZgClzYzMaU
Thats a good video, I read about it in Evo. I would love to have a go in that car.
the journo does rally a Mk2 Escort in his spare time but I could def handle that amount of sideways on track, not so much a rally stage though.
My cradle is pretty bespoke to be fair, it is made for quick change supra diff, t45 light weight, it would not fit a Wrc shell and has different length arms and is made to my 205 track. I suspect it will be over the top for the use i will have for it....few track days, maybe a couple of drag strip runs, poss hill climb and mainly a and B road blasts.
....and one very talented driver :-0.
Its cosworth track set on a Jig so same as the rest mate no different
On a standard Cossie the rods would be set longer, the rods on mine are wound right in. The WRC cradle would need a fitting kit to take a supra diff, mine does not. The WRC cradle does not have a removable bar at the back to take the diff out.
i was not suggesting bespoke geo.
save for going double A arm it was the best I could afford. Double a arm was over 10k more so the cradle is the best I could spec and the t45 saves a load of weight.
of all the builds on here I have not seen much better than a cradle setup.
Last edited by Caddyshack; 12-10-2019 at 08:21 AM.
08-10-2019, 11:52 PM
