VVTLi cam change

The Oily Bits S2 Specific Topics
1

With all the talk of the cam change point and i have to admit that there are the odd times when its a pita, especially when you just fall off cam. Well was thinking, and yes it hurt before anyone asks! I think im right in saying the cam change is electricall controlled by the ecu, if this is anything like the fan control then the ecu just switches the return earth wire.
So in theory a bypass switch could be fitted to effectivley keep the engine ‘on cam’, i appreciate this i not ideal but may help when on track?
So what do uou think?

Gav (bored at work!)

2

forgive me, i’m a technical numpty. would it not just be possible to reprogram it to come in at say 4500?

also noticed, on mine at least, that you have to take it almost to cut-off to keep it in the second cam when changing up - which again seems silly to me as a layman.

3

To alter the rpm change you would have to re program / crack the ecu which no one has done yet.
Was just thinking low tech.
Gav

4

arrrh ok. does the ecu that comes with the engine in the celica have a different cam timing change? if it does, is a swap possible?

thinking logical, as a total numpty.

5

Don’t forget it’s not just the switch over point that you’d need to change, the map for fueling and timing would need to understand the change as well???

Also would the engine run well at lower revs on the wilder cam setting properly?? Someone surely spent a long time working out the optimum point for the switch?

6

Skiddo

Don’t give up your day job, matey

21GG

Still trying to use up some of that left over insulation tape, are we?

7

With all those electronic wizards out there and tuning companies for Toyota stuff, nobody has cracked the ECU?

Or is the ECU a Lotus bespoke one?

8

no plans to give up me day job pesky! a love taking pictures, me.

i assume the cam change point was to make the engine efficent around town?

i seem to remember reading that lotus had to do their own map cause toyota didn’t want to share their hard work - lol.

edit… found this. idiot does google search: The page cannot be displayed.

it seems they swap at 6000rpm

i’ll stick to pictures from now on i promise.

9

mm, not thought about fueling but do we think it would make that much difference? Any one with an engine wiring diagram?
Gav

10

arrrh ok. does the ecu that comes with the engine in the celica have a different cam timing change? if it does, is a swap possible?

Change point is 6200 in my T Sport, about 750rpm too high IMHO

11

There is also a controller CAMCON 101 which does both vetc and vvtli, well despite having a louts ecu surely all output/input signals must be the same as toyota as its all the same sensors and controls? So if the above works by modifying the signal between ecu and sensors one would think it would work on the lotus as well as the toyota/honda?
Gav

12

link:

http://www.powerenterpriseusa.net/manuals/download.php?filename=USDMCAMCON.pdf

Gav

13

I don’t think it’s part of the encrypted ECU data. At any rate, it’s already been cracked here in the States… by a Brit expat, I think.


Hopefully, he’ll come along any moment now and provide some details.

14

21GG

Still trying to use up some of that left over insulation tape, are we?

15

Afternoon jonty! how was the holiday? no piccys? you manage not to get arrested?
Hav

16

Lotus have entirely different electrical systems and ECU so none of the work towards Celicas etc is valid. I know of a couple of companies which have ‘cracked’ Lotus ECU their products will be on the market soon. People have succeeded in lowering the cam change over by a couple of hundred revs but on an N/A application you loose performance if you stay on the more aggressive cam and therefore have more valve overlap.

I also know replacement ECUs will be with us later this year. Its going to get interesting

17

I looked into this last year and it turns out that the std cam change over point is set at the optimum point of the torque crossover point of the two std cams, if you lower the rpm cam change point you will lose power.
I have seen a torque chart that shows the two cams , think it was on Elisetalk.com.

18

The one I saw clearly showed it was not at the optimum place, hence the cam kicking in. When the 2nd cam came there was a step increase in torque.

Apparently for marketing purposes, as some peole really like that

Does anybody have the graphs so we can comment? (it wasn’t as much as 1k rpm anyway)

19

Hey guys over here I’ve got my cam change over at 5750rpm
check out reg tech section on moremonkey.com it works great no bull.

20

Wow, you have a pretty good site over there.
Will check it more often (even if I don’t have an S2)