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Discussion Starter #1
I've tried searching but being the dumb ass I am:wave:, can't find anything.

The cam changeover point in my car seems to vary (stock ecu). Sometimes its normal around 6000 rpm, other times, (usually, but not always,) on a light throttle it feels like there is no change over; the rev noise and acceleration remain constant. It also farts and pops coming off the throttle (sounds fine) when the change over is normal, however coming off the throttle when the changeover doesn't happen it runs / sounds like a normal car.

The rev limiter also kicked in at the change over point once (~6000rpm) recently, the engine was relatively cold (car had been parked for an hour & I wasn't paying attention) so I'm not sure if that had anything to do with it.

So my question is, is this normal or is there something wrong with the ecu or engine. Any thoughts?
 

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00 MRS - 2ZZ NA
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LIFT, the extra burst of power, happens when there's a shower of oil going through your valve cover to lube up the extra camshaft workings.

So if you don't get to the 2nd bar of heat after start up, the car's not warm enough to engage lift, and you're damaging your engine. Don't do it.

And as far as the transition is concerned, get a intake to REALLY notice the difference at partial throttle ;) .
 

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And as far as the transition is concerned, get a intake to REALLY notice the difference at partial throttle ;) .
And lose 10 hp in the process! :coolnana:
 

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LIFT, the extra burst of power, happens when there's a shower of oil going through your valve cover to lube up the extra camshaft workings.
Cameron, the switch on our cars is commanded by the ECU. The oil needed to switch the cam follower is delivered through the follower's pivot shaft.

So if you don't get to the 2nd bar of heat after start up, the car's not warm enough to engage lift, and you're damaging your engine. Don't do it.
On our cars (not sure how it may be on the Toyota) the temperature readout is digital and the ECU doesn't allow the engine to rev over 6000 when cold. This is supposed to prevent us from causing engine damage by being too eager when the engine hasn't properly warmed up. When the digital temperature display first shows (at around 164 deg. F), the ECU will begin to allow higher revs and permit the cam switch.
 

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00 MRS - 2ZZ NA
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I just wish the damned car would shut up so i could stay on the throttle longer. I'm not in the mood to get tickets and so you're stuck shifting at 4k rpm most of the time... if it were silent you could run full throttle most of the time... that's the #1 alure of the Tesla for me. Silence = more throttle, more often, more places, without getting any attention. I don't want to sound like i'm accelerating fast, i want to actually accelerate fast without getting a ticket. People (and the police) don't pay attention to how fast a car is actually accelerating (as long as you're going normal speeds) they pay attention to how much noise you're making doing it... making the car noisier is cutting off your nose to spit your face unless it's a track only car or car that's never driven near the police.

I watched a guy driving down the freeway in an electric ariel atom and i watched him punch the gas several times and the thing absolutely lunged forward from freeway speeds... and nobody realized what was going on but him, and me who was looking for it because i knew he could get away with it.

Not to be a total spoil sport, i can understand how much fun the sound is... i really like the sound getting up on the cams... but i'd trade it away in a heartbeat for something more useful.

To stay on topic, my observation is the chang-over is really only felt when you're hard on the throttle, and moderate throttle it's not that noticeable, if at all... seems normal to me that it wouldn't be so obvious. Now that i think about it, does the car even need to do the cam switch?... is the cam switch a hard requirement or can the ECU just stay on the first cam all the way if it doesn't need the extra power?
 

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NA factory cars are set to 6000/6200 RPM off/on so thats when it all goes into place, it'll vary when it actually happens since its mechanical, the S is at 4400

Lowering it to around 5600-5800 makes it smooth and you lose that little jolt, but its not the optimum switch point for NA, unless you're a track person that wants it to stay on the high cam longer during transitions etc.

We done a coupke of dyno pulls with the cam switched off, it did drop power, i suppose it'd be a 1ZZ then, not sure if can remember which sheets were which.

The lowest i've ever set it is about 5400 on a very light weight car (around 1650lbs), anything lower than that the car got really sluggish, 5600/5800 is getting towards the minimum for the stock weight.
 

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CX- Do you like the S switch at 4400? It seems like the car is still pulling pretty hard on the "little" cam even into the low 5,000s over the "big" cam even when SC'ed... I need to spend more time on the dyno to verify it's not just a fluke of datalogging and seat of the pants, but the car seems to accell better when I switch the cam at 52-5300 vs something lower (I've tried, 42, 44 and 4800 rpms for the exh cam switch).... The above seems to be more evident at part throttle (say 75% for an example) and less noticable at full throttle...

Your thoughts?

Best,

Phil


NA factory cars are set to 6000/6200 RPM off/on so thats when it all goes into place, it'll vary when it actually happens since its mechanical, the S is at 4400

Lowering it to around 5600-5800 makes it smooth and you lose that little jolt, but its not the optimum switch point for NA, unless you're a track person that wants it to stay on the high cam longer during transitions etc.

We done a coupke of dyno pulls with the cam switched off, it did drop power, i suppose it'd be a 1ZZ then, not sure if can remember which sheets were which.

The lowest i've ever set it is about 5400 on a very light weight car (around 1650lbs), anything lower than that the car got really sluggish, 5600/5800 is getting towards the minimum for the stock weight.
 

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Franks car is set to a higher switch point than the stock S, it does help his power delivery, i'd have to go back to the dyno sheets to see how much, as we did it a while ago.
I do like my S's delivery though as its silky smooth.
 

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Cool and good to know... I agree the low switch is smooth. That said, it's still not rough at 5300 when compared to stock...
I was surprised when I was getting slower/longer accell times (consistantly) with the lower switch- particulary at anything less that full throttle opening. I know the dyno can pinpoint where the sweet spot for the switch is, but real world testing never hurts either;) I've got a lot of track time coming up again this weekend and will try several different configurations on the cam. I think I like the 52-5300 switch the best so far as the little cam lugs out of sweepers better than the big cam in that 4600-5200 rpm range...note: I realize "lugging" is something only supercharged cars would dare do on the track:D

Sorry for the thread jack...

Best,

Phil
 

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Discussion Starter #12
Ok so it seems the limiter coming on at 6000 was cause it was cold:up: which is what i figured as it was the only time I revved the car before it was fully warmed up.

So does the ecu 'learn' how you are driving like say a tiptronic gearbox learns, ie light throttle, slight change over, heavy throttle, noticeable change over.
 

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I've had this fickle cam engagement problem since break-in ended. Sometimes late cam at 6800, sometimes no cam switchover. Lately it's late cam, but because it's so late the rev light comes on too quickly thereafter (in 1st). Disconnecting the battery got it working to spec on one occasion; this trick doesn't work anymore. Another thread on board about this from March. Can't tell if it's electrical or mechanical. Solution before warranty expires would be nice! 2006 and only 3400 mi.
 

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So, I'm posting to this thread also to help stave off my depression at not having my car for weeks now. Any ideas why a cam changeover just won't happen? I've had my defective cam replaced and the hydraulic lift part replaced also after when the changeover failed after just the cam replacement. Still no luck with a fix. Any thoughts would be encouraging. The mechanic is going to call Lotus service, but I figure someone here might have info. Thanks. :)

Wendy
 

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Check the output of the ecu that its actually attempting to engage it, that'd be a good first check just to make sure the ecu isn't bad, after that its just a matter of going down the list.
 

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Thank you, CharlieX. I'll let the mechanic know you suggested that. If everything mechanical is ok, then that seems like a good next step to check. Just wondering, have you heard of ECU's failing or some part of them not working?
 

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if the dealer has one in stock its just a swap and a reflash. 10 mins to test, 1 to 1 1/2 hour to replace and flash
 
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