Cams and Adjustable Cam Pulley Settings

[AutoBlackie]

Recently fitted an Adj. cam pulley into my Blacktop. Using stock cams. Learned alot bout how valve degreeing and how it affects the powerband.
I'd say that this is the best power mod (conservative) that I have made. My auto definately needs a lower powerband and I can adjust my pulleys just to deliver that. Beautiful.
Power kicks in bout 3k rpm and its much nicer to drive round town. Still experimenting. Worth the money spent.
Like forummer Yolk says, the stock cam does have lots of potential.

 

[Acoustic]

for basic overall power ....... 4-2-1 extractor ..........

 

[AutoBlackie]

Well it's a system I guess. Depends on what you want. The only thing bout exhaust is, it is harder to alter the length to a specific type of tuning. If you have an exhaust optimised for let's say 3500rpm you are stuck with that. Not with adj pulleys :lol: Go on track can tune to higher powerband!
Of course, exhaust must be of certain standard also la. :)
Here is my setting,
Car body = AE80
Engine = AE111 Blackhead
Exhaust header = AE111
Exhaust (the rest) = AE111
Gear= Auto (nice for lazy ppl! )
Adj Cam = IN 4 degrees retard, EX 5 degrees adv.

Next Mod prob EFN's AFPR! hahaha!

BTW Acoustic, TPS setting, how many ohms you set ah? Gatal want to try la.

 

[AutoBlackie]

He is some experience. Using butt dyno. About adj cam pulleys.

Setting = IN 3 deg. adv. EX no chg.
The car starts to idle a bit irratic. (Suspect compression a bit too high? Still blur bout this) kind of nice to drive but stopping for red light is not much fun le.

Setting = IN 5 deg. retard. EX no chg.
Idling like normal. Power gain unable to feel the difference. (If am not wrong, when VVT is activated, the IN cam is being retarded almost 15 degrees? to make more torque? Low end torque?)

Setting = IN 5 deg. retard. EX 5 deg. adv.
Nice low end torque. Enough high end but bit less. (effectively reducing overlap by 10 degrees)

Other settings will be posted later after more tests with different settings. One thing, the ignition timing will chnage as distributor is connected to one of the cam shafts, I think the EX (Exhaust) one.

 

[TE27levin]

adjusting the exhaust cam will direct effected ur ignition timing too. do u set back the ignition timing when doing adjustment on ur cam ?

when u advance the EX cam, ur ignition will follow it advancing.
advance ignition = more lower end

 

[Acoustic]

Originally posted by AutoBlackie@Feb 15 2005, 00:34
If you have an exhaust optimised for let's say 3500rpm you are stuck with that.

forgot to report in my site that the 4-2-1 extractor system is good from the starting rpm.

i.e. mine was optimised from 5,200 rpm and it pulls all the way to 8,000 rpm very eagerly :)

I don't know about 3,500 ........

A theoretical estimation would be it would still be very good one octave above, i.e. 7,000 rpm.

I seriously recommend people to optimise it starting 4,000 instead. Sure cun all the way to 8,000 rpm.

If want more assurance for high rev, then 4,500 rpm lor.

I regret never do the 4,000 rpm optimization.



extractor effects are not like adj pulleys.

 

[Acoustic]

BTW all the results has been stated in engine text books as well as some website.

adjustment beyond 1 degree in any direction is overkill.

In retard and Ex advance is the most weak setting from what I've read / remember

Best setting is In adv, Ex retard because swallow more air.

Another best setting is both retard. see http://www.my-acoustic.com/Car/adjustable_pulleys/adjustable_cam_pulleys.htm

 

[AutoBlackie]

After that, my friend (herein after called "Ah Ming") reduce the intake back to original, retaining exhaust advance half-teeth. Power come back a bit.

Next retard the intake half-teeth as I advised. More power.

Then retard the exhaust to original. More power.

Finally retard everything all together. Allot more power.

Aiya Acoustic. Which is which la? This is from your link.... :P

 

[Acoustic]

there are two good settings everyone agreed.

choice 1 - intake adv EX retard

choice 2 - both retard

these settings are good because user can feel improvement without loosing anything else.

Ah Ming at first did half-teeth = 3.97 degrees for him

However after much playing like you, he conclude that cannot go more than 2 degrees.

From what I see - he is still inexperience compared to text books, so I think later on he will say no more than 1 degree.

If you go more than 1 degree, you will loose allot of other things....



How shall I put it... there is always 100% power. No matter what you do there will not be 110% or 90%.

The world is fair, god always give us 100%. You want less cannot, you want more also cannot.

So, playing adj pulley only play "when" you want more power.

The saying above is only 33% correct.

Because the 2nd 33% is - "where" loose power, because "MOVED" to more power places.

Finally the last 34% is - "fight with nature, completely no power"

So, by doing 1 degree movement, you'll gain a little without loosing anything.

i.e. int adv 1 and ex retard 1

or both retard 1

you utilise 66% of usage.


But if you go more than 2 degrees then the last 34% takes action against you.

 

[Acoustic]

since you read my site, don't forget to wonder about the "vacuum" before suction ......

no vacuum, no suction ............. NA mah :)

 

[TauhuTauhu]

hmm...how to adjust ignition timing on DLI?

and abt the vacuum chin mentioned...if i release throttle with gear engaged and clutch released, tht means the engine is forced to move without combustion rite?
tht means oso got vacuum rite? so whn we open throttle again, more air will be sucked in than normal at tht instant?? :unsure:

 

[-e f i n i-]

wah acoustic's webby so much info.
actually i know that website already exist quite long ago, since 2003, but what a shame, until now also i havent read it complete yet.
one day when im free im really gonna read everything in the website!

 

[GT20v]

Originally posted by e f i n i-@Feb 15 2005, 17:49
wah acoustic's webby so much info.
actually i know that website already exist quite long ago, since 2003, but what a shame, until now also i havent read it complete yet.
one day when im free im really gonna read everything in the website!

yeah..yeah u shud...thats why he got the super sifu title maaa......dont forget read bill sherwood site also... :D

 

[AutoBlackie]

I found out that if you adv. the IN, the inlet valve will open faster and therefore close faster.
Remember, compression will only begin when the valve is closed. Therefore, closing faster, better compression. An guess what if you retard. Yeap, less compression. Most ppl that have metal gasket would know, higher compression will improve mid power...

As for the exhaust adv. the EX, the exhaust valve will open faster, just before BDC. Why before and not at BDC? So that the upward stroke does not have to fight with the pressure generated by the combustion. Earlier evacuation means less resistance. However, if too early, means not fully utilising the power generated by the combustion.. This part of the cycle is refer to as Blow Down.


Then there is also the overlap to consider. The point whereby both the IN & EX is opened, overlapping each other. Ex closing, In opening. Big overlap is good for higher powerband. As the exhaust is being pushed out, a siphon effect will pull in new mixture from the IN valve while it is opening. If overlap is too much, the new mix will go out the exhaust. However, big overlap is good for high rpm as there is more time for mixture to get in and exhaust to get out.

:lol: I am lousy at making things sensible. Well making power is not as easy as making babies. :P Anyway do not have a dyno. Only my butt!

Current setting. IN remains as stock ( Retard will loose compression), maybe will advance it later. EX adv 5 degrees. Loose more combustion but seems to benefit from less resistance on the exhaust upward stroke. Tried 7 degrees, feels like too much.

OK nough said. Sorry for boring. You ppl. Still dunno if what I wrote is right. Learned all I know from the Internet :)

 

[TauhuTauhu]

Remember, compression will only begin when the valve is closed. Therefore, closing faster, better compression. An guess what if you retard. Yeap, less compression. Most ppl that have metal gasket would know, higher compression will improve mid power...

if the IN is advanced, tht means the valves will be closed b4 BDC...how can tht give higher compression ratio?
unless u have high duration cam, adv the IN and intake valves will be opened earlier, and will be closed after BDC?

:unsure: :unsure:

 

[cuscostrutbrace]

ERm....i retard my 4ag tvis intake cam by one teeth,surely can feel the top end a bit,no effect on idle ...just like before,at 1100-1200 rpm(quite high),before this i advance the intake by one teeth,no power at all,even at lower revs...both with stock ignition timing ;)

 

[AutoBlackie]

if the IN is advanced, tht means the valves will be closed b4 BDC...how can tht give higher compression ratio?
unless u have high duration cam, adv the IN and intake valves will be opened earlier, and will be closed after BDC?

If u look at a blacktop 4age, it comes with a 250 degrees cam. Meaning to say that the valve will open 250 degrees of duration. In a four stroke engine, one stroke is 180 degrees (TDC to BDC or vise versa) which leaves 70 degrees. Where is the 70 degrees.

Take the inlet valve. It opens at abt 10 degrees before TDC then goes to BDC and after 60 degrees after BDC it closes. 10 + 180 + 60 = 250.

Bill Sherwood's page says that the 4AGE AE111 (with VVT off) IN opens 5 degrees before TDC something like 5 + 180 + 65 = 250. Here you can see the IN valve if you advance like 5 degrees it'll still be OK. It'll become 10 + 180 + 60. Looking at the 180 - 60 and 180 -65, you can see that by closing the valve earlier, the compression gains.

 

[TauhuTauhu]

if retard IN.....it's most likely like wat chin said?
the valves are still close at the starting point of intake stroke...thus causing a vacuum inside...
then whn valves open, air rush in faster....then whn reach BDC, valves still open...and the air r still moving in coz of something like inertia?? so more air inside combustion chamber?? :unsure: :unsure:


cincai tembak oni :lol: :lol:

 

[AutoBlackie]

CUSCO,
I read somewhere one teeth is 7.5 degrees. As the pulley have 48 gigi. 360/48=7.5 (can't confirm this, anybody?). Dunno if its wise to make such a big adjustment. May I confirm that by turning clockwise is advance and anti-clockwise is retard?

Get adj cam pulley is safer and more accurate.

 

[TauhuTauhu]

Bill Sherwood's page says that the 4AGE AE111 (with VVT off) IN opens 5 degrees before TDC something like 5 + 180 + 65 = 250. Here you can see the IN valve if you advance like 5 degrees it'll still be OK. It'll become 10 + 180 + 60. Looking at the 180 - 60 and 180 -65, you can see that by closing the valve earlier, the compression gains.

hmmm...get it now...coz stock 20v's cam r quite high in duration edi...tat means even if u advance the timing, the valves r still open whn piston at BDC....

:rolleyes:

try more different cam timings and tell us the results.....interested to noe...