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Discussion Starter #1
I'm just doing some reading about cam phasing and fuel economy, trying to understand more about it and i'm curious to know wether it is possible to override the variator?

I understand it is electrically actuated (presumably by a signal from the EMU?). So can you just take control away from the EMU and have a switch to apply this signal?
 

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Discussion Starter #2
I've never heard anyone say their variator has stopped switching so I think I might be wrong about my thoughts here
 

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there was a guy on here some time ago suggesting machining up a 'blank' variator and getting rid of it altogether..
I guess you'd just have to phase the camshaft in for whatever engine characteristics you prefer.. the old fashioned way..

don't know how it would effect oil feeds and ecu etc..?

I havn't forgotten the bushes.. just away at the mo.. back next week ;)
 

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It's controlled by a solenoid that allows or stops oil flowing to the variator. Easy to rig this up to a switch instead of the ecu, in theory at least...
 

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See Twinspark - very good article. Under the 'Twin spark' heading, there is information about the variator.

From my 156 knowledge I recall that the engine will not idle properly with the cam in the advanced position, so below 2500RPM, the timing is retarded. Bizarrely, the control strategy advances the cam for mid-range speeds (2500RPM+) and then retards it for high speeds. I can't understand why advanced cam timing wouldn't be best for high speeds. Perhaps the shortened inlet manifold (when over about 5200RPM) has something to do with it.

Anyway, I get amazing economy from my 2.0TS 156 and wouldn't dream of tampering with it. Average on trips is 6L/100km or 47mpg. I blame the excellent Selespeed transmission and possibly a dodgy MAF - it just runs really well and I get 1000km (620 miles) out of one tank. Hope my Spider will be similar...

-Alex
 

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Discussion Starter #6
Thanks Alex by shortened inlet do you mean the effect of the resonantor box or something else?

Cheers Seadart, btw the project I am working on now is replacing Seawolf on T23.

I wonder if the variator allows any valve overlap? In which case the turbo junkies out there could benefit from disabling it?
 

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[. Bizarrely, the control strategy advances the cam for mid-range speeds (2500RPM+) and then retards it for high speeds. I can't understand why advanced cam timing wouldn't be best for high speeds.

Yea does seem a bit arse about face doesn't it.. but after a lifetime of dialling in motorbike camshafts I can assure you that retarding the cam tends to increase top end power and advancing the cam timing increases low end torque.. a variator.. in theory at least.. gives you the best of both worlds.. when it works :)

A screamin' demon engine is ok.. but when you're in a traffic jam and you have to leave 100 yards between yourself and the car in front before you dare let the clutch out...............
 

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No way. Never in a million years.
Lol!
Well, good thing I'll keep my 156 as well, then :)
Just averaged 6.1L/100km on tonight's 130km trip Hamilton-Auckland, have had as low as 5.9 and as high as 6.4, sitting at exactly 100km/h for about an hour. Odometer rolled over 252,000km the other day. Happy times...

Don't know how you get on with the 166 but I find mine hardly ever gets below 12L/100km (23mpg)...? Fortunately I've arranged to sell it.

-Alex
 

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Yea does seem a bit arse about face doesn't it.. but after a lifetime of dialling in motorbike camshafts I can assure you that retarding the cam tends to increase top end power and advancing the cam timing increases low end torque.. a variator.. in theory at least.. gives you the best of both worlds.. when it works :)

A screamin' demon engine is ok.. but when you're in a traffic jam and you have to leave 100 yards between yourself and the car in front before you dare let the clutch out...............
Thanks for the explanation :) yes, torque is what you need for economy too, and it's nice to have a smooth delivery even though that variator is switching in and out... I think it works brilliantly.

-Alex
 

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With Regards to fuel Economy, remember that each country has different environmentals, I remember when we tuned A series engines, if we were to send the car with that engine to america, we would need to send one of our tuners over with the engine to sort it out, not only for the octane difference in fuel, but air pressure, density, it all made a difference, especially with Carb'd engines, So I do believe fuel economy can be increased depending on which climate you're situated in :)
 

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With Regards to fuel Economy, remember that each country has different environmentals, I remember when we tuned A series engines, if we were to send the car with that engine to america, we would need to send one of our tuners over with the engine to sort it out, not only for the octane difference in fuel, but air pressure, density, it all made a difference, especially with Carb'd engines, So I do believe fuel economy can be increased depending on which climate you're situated in :)
Yes, true. I guess my hope was just that a Spider with the TS engine would have similar fuel economy to a 156 with the TS engine. Maybe I'll find out next week :)

-Alex
 

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Thanks Alex by shortened inlet do you mean the effect of the resonantor box or something else?
I meant the variable-length plastic inlet manifold - not sure if all TS GTVs/Spiders have this, think it might not be on the CF1 (alloy cover) engine but I'm not certain.

-Alex
 

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With Regards to fuel Economy, remember that each country has different environmentals, I remember when we tuned A series engines, if we were to send the car with that engine to america, we would need to send one of our tuners over with the engine to sort it out, not only for the octane difference in fuel, but air pressure, density, it all made a difference, especially with Carb'd engines, So I do believe fuel economy can be increased depending on which climate you're situated in :)
Really? well that would offer some explaination. There's no way we can get in the high 40's in blighty though, as nice as it would be!
 

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I meant the variable-length plastic inlet manifold - not sure if all TS GTVs/Spiders have this, think it might not be on the CF1 (alloy cover) engine but I'm not certain.
It came along in 1998 with the change to CF2 (155bhp) spec.
CF1 (150bhp) don't have it.
 
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