Slow pumping cam follower? Better?
Discussion
Hi. Could be crazy talk. Speaking to a guy in the pub (already sounds dodgy!). I mentioned the 'issue' of lean running below 2000 rpm in the catalyst equipped engines. I have a year 2000 Griffith 500. Not a major issue for my car compared to some, but, could still be better.
He mentioned cam followers that pump up more slowly, hence giving lower valve lift at low rpm, like basic version of variable cam timing. He told me the name of them, but given we were in the pub I have forgotten!
Sounds like a good theory? Or not? Is this real?
Thx
Nic
(Trying to cut down on my drinking!)
He mentioned cam followers that pump up more slowly, hence giving lower valve lift at low rpm, like basic version of variable cam timing. He told me the name of them, but given we were in the pub I have forgotten!
Sounds like a good theory? Or not? Is this real?
Thx
Nic
(Trying to cut down on my drinking!)
Great topic
Just replace the Ecu system.
Sounds infinitely a more reliable way to control fuelling with the added bonus of being able to advance/ retard spark at will which can and is used to add or remove exhaust gases. / leaving exhaust gases in the combustion chambers/ bores restricts the amount of air and fuel the cylinder can take which is a simple way to make the engine less powerful but more economical.
That’s the equivalent of timing the engine to have valve almost about to close as mixtures are added/ removed so only having a small opening window.
Same effect as what that chap sounds like he’s talking about.
When the engine goes into a light throttle fuel saving mode ( cruising along) I’m sure the timing is mapped/ adjusted to keep more exhaust gases in the cylinders and so restricting how much the engine can draw in which has a huge benefit in fuel economy figures on modern cars. I think you need variable valve timing for that to be most effective. I’m not sure how much mappers use this timing when mapping TVR though. My car has recorded 29 mpg at 70 -75 mph on a long long journey through mid France on a modern ecu. I think it was at least 26 with a freshly built engine on CUX though.
That’s my layman’s understanding.
You get enough clatter with the buggers pumped up full so sod having them loose on a cold engine but I have no idea what I’m talking about
if they are only half pumped up wouldn’t that mess up the pre loads? I like the pub banter though. Sounds like a cool idea that might be feasible to my restricted understanding of such things,,, especially after a few pints
Just searched, seems they are well known, noise being the biggest issue.
I would still like a very smooth bottom end, perhaps sacrifice top end power?
ECU changes not going to cook it, given the need to protect the Cat is the over riding function of the ECU, not to make it smooth…
Nic
I would still like a very smooth bottom end, perhaps sacrifice top end power?
ECU changes not going to cook it, given the need to protect the Cat is the over riding function of the ECU, not to make it smooth…
Nic
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