Adjustable Cam Gear/Pulley

[JackWaiKit]

Hai all,
U r invite to advice for me that...
What is the function or improvement can be produce after install an adj can pulley???

Pls kindly answer me yoh!!!

Thanks

 

[karl5511]

The profile pic, is it your car? Black putra, white P1 Buddy Club rim...haha it is 99% like my ride.
Well, adj cam pulley, there's a lot of topics discussed before.

 

[GSR06]

Hey,
Nice ride you have there. You know who I am huh :P

Just to drop by to say hi... we shall meet again...

 

[alamdamai1]

planning to do this mod very soon....but before that, need the help of Sifus here...

i've noticed the cam timing for our 4G15 is different between a Carbie and EFI models..append below is the spec sheet...

hence, can anyone confirm this and if so, would it be worthwhile to change my stock Carbie Cam to the EFI version for better engine efficiency as the exhaust valve timing for the EFI opens later compared to the Carbie model...

members advise is highly appreciated...many thanks... :help: :help: :help:

http://img268.imageshack.us/img268/6193/4g15camtiming.th.jpg

 

[rex79gt]

recently i did mine as well
i;m driving a campro engine 1.6 auto
initially setup based on manual din work as the tuning for auto n manual is different
this is the result i tried together wif my friend

bout brand of ACP, some said those like HKS which cost a bomb, is very accurate when adjusting the cam pulley -.-

 

[alamdamai1]

rex79gt, could you share with us your previous settings based on manual transmission as well as for the auto tranny...by the way, how much does the HKS pulley cost?

 

[AD_EG]

bro about ACP,

you can get those aerospeed ones...not so expensive...

about setting your cams...its best you get the mech to set your cams for you....

i found this link very helpful when i was learning about cams..hope this helps.

Camshaft Fundamentals

 

[alamdamai1]

Sifu, upon reading further about the function of an adjustable cam pulley, i've just discovered that by advancing the cam timing, the inlet valve would open & close earlier while the exhaust valve would open & close later...

hence, izzit correct to say that by advancing the cam, the valves overlap period will increase as depicted below?

http://img163.imageshack.us/img163/2209/valveoverlap.th.jpg

http://img41.imageshack.us/img41/2299/valveoverlap2.th.jpg

if so, an article below stated this would have detrimental effect to our fuel efficiency which i would like to quote below...

"More overlap decreases low-rpm vacuum and response and improves the signal provided by the fast-moving exhaust to the incoming intake charge in the midrange, often providing noticeable engine acceleration improvements. Less overlap can increase efficiency by reducing raw fuel seepage into the exhaust and improve low-end response due to less reversion of the exhaust gases into the intake port."

http://www.hotrod.com/techarticles/engine/hrdp_0908_variable_valve_timing/index.html

thus, may i enquire has anyone experienced any deterioration to their FC when they advanced their adjustable cam pulley?...

 

[JackWaiKit]

Sifu, upon reading further about the function of an adjustable cam pulley, i've just discovered that by advancing the cam timing, the inlet valve would open & close earlier while the exhaust valve would open & close later...

hence, izzit correct to say that by advancing the cam, the valves overlap period will increase as depicted below?

http://img163.imageshack.us/img163/2209/valveoverlap.th.jpg

http://img41.imageshack.us/img41/2299/valveoverlap2.th.jpg

if so, an article below stated this would have detrimental effect to our fuel efficiency which i would like to quote below...

"More overlap decreases low-rpm vacuum and response and improves the signal provided by the fast-moving exhaust to the incoming intake charge in the midrange, often providing noticeable engine acceleration improvements. Less overlap can increase efficiency by reducing raw fuel seepage into the exhaust and improve low-end response due to less reversion of the exhaust gases into the intake port."

http://www.hotrod.com/techarticles/engine/hrdp_0908_variable_valve_timing/index.html

thus, may i enquire has anyone experienced any deterioration to their FC when they advanced their adjustable cam pulley?...

What a good findings...
And bout your question... I guess most of the ppl or car owner will always depend on their foreman to set for them(included) me...
I do interesting what is retarding the inlet degree!!!
Guys... Appreciate with your share & put it here if anythings more!!!

 

[AD_EG]

yes i have experienced slight difference..my FC increased but then again it might not be drastic or noticeable to some ppl...my case was because right after i set cam i had to re-tune my car...and the tuner didnt do a good job tuning the car....the Fc difference wasnt much...

 

[rex79gt]

wanna ask sifu here
i installed my adjustable cam pulley not long ago
n realised the setting on my cam pulley changed
izzit due to the quality of the adjustable cam pulley?
currently i'm using P2R brand
i did tried to screw the nut back but they r all tight

 

[^pomen_GTR^]

*alam damai..

i've just discovered that by advancing the cam timing, the inlet valve would open & close earlier while the exhaust valve would open & close later...

-your engine was sohc rite?? or is it dohc already???actually for a sohc engine there's very little u can gain by changing ACP......

this is because in sohc engine.....when u advance the pulley by 1degree.....intake valve would open earlier and close also earlier.....since the same cam also working on exhaust valve...thus, exhaust valve also would open and close early.....


different on dohc engine...where u can play intake camshaft and exhaust camshaft timing separately....so u would have a wider powerband/range to play with....