R500 with the sequential box
Discussion
fergus said:
The lack of an ign. cut almost negates the purpose of this box, as you can shift very quickly with an h pattern gate (assuming your synchros are in fine fettle) and the dogs aren't worn.
Very true, but the initial main purpose of the box was to sort the racers' propensity to nuke the synchros on the Caterham 6 speed in a minimal amount of time. They needed a new gearbox, so it was most sensible to fit the Quaife sequential as it was an off the shelf straight swap. It then 'required too much more electrical complexity' to fit a cut out... Welcome to Caterham 
Personally I think the C400 would be spectacular with a paddle shift!
Several interesting bits of misinformation here....
Dino, the lift enables the dogs to disengage the current driven gear. Re-engaging dogs when selecting the next (higher or lower) gear needs to be done with the engine speeds reasonably well synchronised - i.e. not letting the RPM fall away to idle.
The issue with the props is down to the quality of the UJ's used. Talk to Bailey Morris who make Caterhams props and they will tell you the standard props are made to a price. Soem of the castings are Turkish made, and without wishing to appear racist, there is a general impression of engineering quality standards in that country.
The bigger joint is a good idea, but it requires a larger tube, which transfers a greater degree of torque shock load, thus attacking the diff mounts.
Do the race cars user 4 or 6 mounts on the diff, anmd are the loads distributed over a wider area? You can see where on my chassis I added the two extra mounts and ran the tubes supportinmg them right out to tyhe sides of the chassi to minimise the taorge moment of inertia. Here http://www.the-webbs.com/k2rum/images/k2hist8.jpg
Its interesting Caterham do not recommend downshifting without the clutch. People will do this whether you tell them to or not, especially on the road if the new gearbox downshifts anything as sweetly as the older type I have. Yes, when driving quickly the tyres chirp if you do not heal and toe and its at that point where your diff gets the massive torque moment. I had some special torque resiliant tubing for my prop rated at 300lbs/ft. Clutchless downshifts twisted that, so its a good indication that the downshift forces are far greater than the upshift.
Point is, you should only do a clutchless downshift if you are effectively healing and toeing. The very fact that your left foot is redundant however, means you should be left foot braking and doing your best to keep revs in the sweet spot with the loud pedal!
Dino, the lift enables the dogs to disengage the current driven gear. Re-engaging dogs when selecting the next (higher or lower) gear needs to be done with the engine speeds reasonably well synchronised - i.e. not letting the RPM fall away to idle.
The issue with the props is down to the quality of the UJ's used. Talk to Bailey Morris who make Caterhams props and they will tell you the standard props are made to a price. Soem of the castings are Turkish made, and without wishing to appear racist, there is a general impression of engineering quality standards in that country.
The bigger joint is a good idea, but it requires a larger tube, which transfers a greater degree of torque shock load, thus attacking the diff mounts.
Do the race cars user 4 or 6 mounts on the diff, anmd are the loads distributed over a wider area? You can see where on my chassis I added the two extra mounts and ran the tubes supportinmg them right out to tyhe sides of the chassi to minimise the taorge moment of inertia. Here http://www.the-webbs.com/k2rum/images/k2hist8.jpg
Its interesting Caterham do not recommend downshifting without the clutch. People will do this whether you tell them to or not, especially on the road if the new gearbox downshifts anything as sweetly as the older type I have. Yes, when driving quickly the tyres chirp if you do not heal and toe and its at that point where your diff gets the massive torque moment. I had some special torque resiliant tubing for my prop rated at 300lbs/ft. Clutchless downshifts twisted that, so its a good indication that the downshift forces are far greater than the upshift.
Point is, you should only do a clutchless downshift if you are effectively healing and toeing. The very fact that your left foot is redundant however, means you should be left foot braking and doing your best to keep revs in the sweet spot with the loud pedal!
Re the shifting cutouts, its a lot more scientific than a timed cust if you want the gearbox selectors to last very long. Closed loop, where the cuts is driven by the actual disengageing and re-engaging of the gears, is a far bettwe solution than static cuts.
The cut duration also varies considerably between different gears, so the cut needs to gear dependent, and also a static cust needs to consider whether you are going up or down the box.
The cut duration also varies considerably between different gears, so the cut needs to gear dependent, and also a static cust needs to consider whether you are going up or down the box.
Fat Arnie said:
And what makes you believe I haven't even seen a car, let alone sat or driven one?
The fact that you said that you weren't sure if the car had a handbrake under the dash. You then said this was a marketing no-no. Surely if you had seen one you would have seen that the handbrake was in the middle?I am not trying to tie you in knots - i am just keen to learn more about the R500 before mine arrives (with it's sequential gear box by the way)
OJ, Correct. It takes a bit of practice, but makes the gear transition much smoother. It is all really down to the RPM uplift change the gearchange requires. Its ,much more critical 3nd to 2nd than it would be 6th to 5th. 6th to 5th can be accomplished with a simple lift anyway.
Atom-mic - The R500 press car is not sequential. Thats the one I've seen, and it had an ordinary S3 chassis. It is this fact which prompted my initial question. Caterham Tech seemed unwilling to disclose the information when I asked.
Atom-mic - The R500 press car is not sequential. Thats the one I've seen, and it had an ordinary S3 chassis. It is this fact which prompted my initial question. Caterham Tech seemed unwilling to disclose the information when I asked.
Fat Arnie said:
Atom-mic - The R500 press car is not sequential.
Arnie, it was when i drove it - which one did you see? Did you get the chance to drive it - what are your thoughts on the engine? (assuming that the one you saw was the H pattern one and therefor you are yet to try the sequential one)It made me smile a lot!
The white R500 press car has the sequential 'box and is fecking awesome! Only been in the passenger seat but have had a really close look at evrything (inc the diff struts something you seem to have missed)
How come Fat Arnie seems to know both everything and nothing all at the same time? I think you must have a new R500 on order, hence asking all the questions but then wait a minute, you seem to also be saying that Caterham have got it all wrong and the cars are not built correctly and the cars will fall apart. Am I missing something??
How come Fat Arnie seems to know both everything and nothing all at the same time? I think you must have a new R500 on order, hence asking all the questions but then wait a minute, you seem to also be saying that Caterham have got it all wrong and the cars are not built correctly and the cars will fall apart. Am I missing something??
Fat Arnie said:
Re the shifting cutouts, its a lot more scientific than a timed cust if you want the gearbox selectors to last very long. Closed loop, where the cuts is driven by the actual disengageing and re-engaging of the gears, is a far bettwe solution than static cuts.
The cut duration also varies considerably between different gears, so the cut needs to gear dependent, and also a static cust needs to consider whether you are going up or down the box.
I guess magneti marelli have it all wrong with the 182 and 197 clio cup cars and also seat's DSG box also shifts like this....The cut duration also varies considerably between different gears, so the cut needs to gear dependent, and also a static cust needs to consider whether you are going up or down the box.
Fat Arnie said:
Point is, you should only do a clutchless downshift if you are effectively healing and toeing. The very fact that your left foot is redundant however, means you should be left foot braking and doing your best to keep revs in the sweet spot with the loud pedal
What's the point of the blip if the gears are in constant mesh (as per a seq. box if the clutch isn't used), as the blip wouldn't have any effect in raising the engine revs to the road speed when the lower (numerically) gear was selected?When I perform downshifts in my race car, I H&T but use the clutch. I also LFB but this is more to stop the understeer....!
Fat Arnie said
The R500 press car is not sequential. Thats the one I've seen, and it had an ordinary S3 chassis. It is this fact which prompted my initial question. Caterham Tech seemed unwilling to disclose the information when I asked.
Wrong, there's one with the sequential box and one without, both with R500 chassis.
The R500 press car is not sequential. Thats the one I've seen, and it had an ordinary S3 chassis. It is this fact which prompted my initial question. Caterham Tech seemed unwilling to disclose the information when I asked.
Wrong, there's one with the sequential box and one without, both with R500 chassis.
Edited by csr on Thursday 4th September 19:26
Fergus,
They are not in constant mesh during the change. An open throttle allows engine rpm to increase momentarily upon disengagement of the dogs. Effectively you a re taking a very short duration lift to allow this.
This is also why correct choice of clutch/flywheel (and why I asked what clutch they are using)is essential, as the engine will not pick up if there is too much rotational latency. The crank is a critical part of this too. I do not know what crank is in the R500 Duratec - is it significantly lighter than the stock item? Generally EN40 cranks from Farndon are not any lighter than the OEM item. DKE/Arrow on the other hand are much lighter - in the VX the top spec race crank is only just over half the weight of the stok item.
CSR - The two journos I met only had use of the 6 speed one.
They are not in constant mesh during the change. An open throttle allows engine rpm to increase momentarily upon disengagement of the dogs. Effectively you a re taking a very short duration lift to allow this.
This is also why correct choice of clutch/flywheel (and why I asked what clutch they are using)is essential, as the engine will not pick up if there is too much rotational latency. The crank is a critical part of this too. I do not know what crank is in the R500 Duratec - is it significantly lighter than the stock item? Generally EN40 cranks from Farndon are not any lighter than the OEM item. DKE/Arrow on the other hand are much lighter - in the VX the top spec race crank is only just over half the weight of the stok item.
CSR - The two journos I met only had use of the 6 speed one.
The former, but didn't drive it. I got an idea what it must have been like though when another journo did a back to back test (R500 dropped at Caterham, drove straight to my place) with my car.
Quote goes something like "After the R500 I never realised an extra 100bhp/tonne could feel so significant"
Quote goes something like "After the R500 I never realised an extra 100bhp/tonne could feel so significant"
Fat Arnie said:
The former, but didn't drive it. I got an idea what it must have been like though when another journo did a back to back test (R500 dropped at Caterham, drove straight to my place) with my car.
Quote goes something like "After the R500 I never realised an extra 100bhp/tonne could feel so significant"
I have read both pistonheads and blatchat for a long time in the build up to buying my first seven (a few years back now) and have noticed that every thread you contribute ends up with you mentioning your car.Quote goes something like "After the R500 I never realised an extra 100bhp/tonne could feel so significant"
I hate to break it to you, but i am not interested in your car. As wonderfully fast
and well built 
as i am sure it was. What you have to appreciate is that what i am interested in is a factory built car with a warranty and a residual value. A custom, one off car can always be made to be faster than the original if you throw enough money at it. However fast it is though, you must have spent an absolute fortune on your car and from what i understand you are struggling to sell it.To me (and i am sure almost everyone would agree) an off the shelf R500 offers 99% of the performance of your car with 99% less hassle and about 40% of the cost. And if i wanted to sell it at any point it will be easy peasy!
Cheers,
Mick
Edited by atom-ick on Friday 5th September 09:27
P.Nott said:
Whoa thats done it. From what I have read elsewhere you will soon be receiving a nonny mouse email Mick.
Why would that be the case? Unlike many on here i am not criticizing Fat Arnie's car at all - just pointing out that it isn't relative to this particular thread. I actually have a huge amount of respect for his car, and from what i have read (i have never seen the car) it is a labour of love.Edited by P.Nott on Friday 5th September 10:04
Why does everyone always assume that everyone is out for a fight?
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