Rally Cars tech stuff

[worldrallynews]

A helper spring is used to keep the main spring tight between the perches when the suspension is at full droop. It "helps" keep the main spring snug, if you will. A helper spring has a very soft rate, on the order of 10 lbs/in. It's just strong enough to push the main spring up against the upper spring perch, but that's about it.

Thank you!

[cali]

Guys, It's a brilliant topic! I'm learning with every post. Keep up the good work, as I will not contribute here anything due to my lack of knowledge. But it is sure fun to read about it.

[stefanvv]

Polo's aerodynamics explained - Rally the World | Volkswagen and the Polo R WRC - rallytheworld.com

[OldF]

This excellent post by Zico deserves to be here. It's from a thread ”two step launch” few years back.



Where are you Zico?


http://www.motorsportforums.com/wrc/...tml#post553319

[Coach 2]

Attachment 3093

Maybe more over-boost than ct-pressure dimviii?

[FliegenderZirkus]

Hello everyone, I hope my first post will be in the correct thread... I was wondering about manufacturers switching from mechanical to electric water (coolant) pumps, which seems to be the trend for the future (despite many problems with them in the past). From what I found so far they are used in Peugeot 207 S2000 and in Mini John Cooper Works WRC & S2000 1.6T. Do you know of other rallye cars using electric water pumps? And what is so fragile about them that they caused many drivers retire from events (e.g. Václav Pech in Barum Czech Rally 2012 lately)? I suspect that the manufacturers mostly use the pumps you can find in BMWs (in E90 etc.), which should be pretty reliable. By the way, are the homologation documents with detailed specifications available to the public? Thank you for any replies!

[br21]

I think there are many reasons for electric water pumps. They do not use engine power (like auxiliary belt run water pumps do), smaller risk of them not working (when the belt broke), you can position the pump where you want (weight distribution, etc.), you can easier bleed the system (run the pump before the engine starts), let the pump work after turning off the engine, etc. In S2000 car it might be also problematic to use belt run pump because of very high engine revs?
At the beginning there were a lot of problems with electric water pumps, but now I think they are pretty reliable.
There is also electric water pump in Fiesta S2000 and it's also based on some BMW pump.

[FliegenderZirkus]

Thank you for the answer and tip on Fiesta S2000, I didn't know about that one. The advantages of electric pumps seem to be clear indeed, I think we will see more of them in the close future. What I would actually be interested in are details about how the temperature control is implemented etc., but such information is pretty secret, I can imagine. Or is there just a regular thermostat on the bypass hose of the radiator and the rpm of the pump is kept constant? That is probably not the way BMW does it...well if anyone has a tip where to look I will certainly appreciate it.

[br21]

I don't know exactly how it is done, but I will find out, no problem! There sure is no such thing like thermostat. There is only Engine Coolant Temperature sensor which gives data to the ECU and it controls the pump.

[dimviii]

for sure no thermostat,as the pump pulley is not working when engine is cold.