Jump to content
SAU Community

Recommended Posts

hello all,

how much power can u gain by advancing C.A.S from center position??

reason i ask is because i had my c.a.s advanced now i have put it more back to the center position because im working on fuel consuption thourght it might help but i have seemed to have lost power :cool: so if anyone knows how much power your playing with by adjusting c.a.s would be a great help...

Edited by rich flavour
Link to comment
https://www.sau.com.au/forums/topic/214031-cam-angel-sensor-cas/
Share on other sites

hello all,

how much power can u gain by advancing C.A.S from center position??

reason i ask is because i had my c.a.s advanced now i have put it more back to the center position because im working on fuel consuption thourght it might help but i have seemed to have lost power :D so if anyone knows how much power your playing with by adjusting c.a.s would be a great help...

Your question cannot be answered in a direct sense..ie how much power am I playing with...There is an optimal ignition advance and it is based on so many things...some of theses things are fuel RON, compression ratio, afr, inlet charge temp and combustion chamber design...

If you retard ignition timing you do not yield as much energy from the fuel...if you advance the timing too much you yield all of the energy from the fuel but because the peak occurs prior to TDC and some or most of that energy is wasted in trying to force the piston down too early. If you do this you are trying to rotate the engine backwards...In reality this doesn't happen due to inertia of the engine but you still do mechanical damage in the process..

Bottom line is if you are running a stock setup, run stock base timing...It is an optimised compromise of power, economy and safety...

standed timming spot didnt seem to pull any where near as hard as when it was advanced i cant go back as it seems slow

also can some explain what happens when the enhine detonates?

Edited by rich flavour
standed timming spot didnt seem to pull any where near as hard as when it was advanced i cant go back as it seems slow

also can some explain what happens when the enhine detonates?

As I said ignition advance is a compromise...If you want to trade off safety run more of it and get more power...but you are closer to detonation or pinging as some say...With stock ECU detonation is your enemy as well because if the knock sensors pick up detonation it goes into rich and retard mode...so you dont win...

At low power levels detonation will f**k the engine over time...It damaged piston crowns and combustion chamber surfaces...it also roots your spark plugs...other not so visible signs are shortening life of gudgeons pins and conrods etc etc

At high power levels detonation can f**k up your engine in an instant!!! Bang... broken piston, gudgeon pin, conrod and holes in the block as well as bent valves...

There is an optimal ignition advance and it is based on so many things...some of theses things are fuel RON, compression ratio, afr, inlet charge temp and combustion chamber design...

had my CAS adjusted (on dyno) with ghey fuel (98 vortex, but drove like 95). I hope that doesn't hurt the engine. i've been using awesome Ultimate recently (last couple of months fuel has been scarce and crap quality) and i'm wondering if it'll affect the current ignition advance setup...

sorry to hijack

Edited by R338OY
well the cas on my car has been advanced since i have had it, dont think i have ever had detonation before.

rich and retard mode how will the car run during this mode???

Reminds me of the rev limiter

Sometimes it just feels flat too

Edited by R338OY

asuming your running a standard ecu,

get a timing light and set your timing at idle to 15degrees BTDC

then leave the thing alone.

you will only cause yourself issues by playing with it.

different parts of the ignition map need different amounts of timing, so playing with the cas is a bad idea.

if you wind it up to 20 degrees base timing you might think wow this pulls well at lower revs, and seems to go much better.

but your whole timing map has been changed 5 degrees.

when your on full boost as little as 1 degree can cause it to ping in certain spots of the map. and unless you have a aftermarket ecu showing you that its pinging you may never here it.

WTF does advancing a CAS mean??? I thought it either worked or didnt. Is it the equivalent of electrically fooling the engine into advancing the timing, but seems like the mod would be permanent. Is it literally just changing the angle the CAS is attached to the engine? Sounds like a pretty dodgy mod hahah

Sounds like a pretty dodgy mod hahah

On a dyno it's a reliable way to see how a modified engine reacts to timing advance. Obviously a stock car needs stock timing. But with some mods and esp. ECU mods, advance = powah.

Doing a guess job in the backyard after a few beers. That's dodgy.

On a dyno it's a reliable way to see how a modified engine reacts to timing advance. Obviously a stock car needs stock timing. But with some mods and esp. ECU mods, advance = powah.

Doing a guess job in the backyard after a few beers. That's dodgy.

there was no guess job i bought the car like this i went back to a more center position because im trying to get more fuel out of a tank but i lost power so this is why i ask....

there was no guess job i bought the car like this i went back to a more center position because im trying to get more fuel out of a tank but i lost power so this is why i ask....

Putting it back is what caused the power loss. You should see more mileage, as a tradeoff for less power. My car was sluggish until i advanced my timing. Now i use more fuel :)

so the car wont go anywhere like wont drive normaly exceleration lost?

is it safe to keep it how it was in the advanced spot if im having no problems?

Rich and retard is from what I have experienced, only subtle. The car just feels flat...

The CAS position for stock base timing (15btdc) varies from engine to engine...That is why it is adjustable...For stock engine with new cam belt and no adjustable cam pulley etc 15 deg btdc would be close to the middle of the adjustment slot..

You need to become familiar with what pinging sounds like...If you know what it sounds like you can advance until pinging occurs and then retard it 2-3 deg to be safe...If you dont know what pinging sounds like (it harder to hear with loud exhaust) get it set by a workshop...You can do it yourself with timing light...there are many threads on how to do this...

there was no guess job i bought the car like this i went back to a more center position because im trying to get more fuel out of a tank but i lost power so this is why i ask....

if you didnt use a timing light then you guessed.

as i said get a light, set it at 15 btdc and leave it alone.

if your worried about economy get it checked on a dyno,

if you cant afford the fuel bill then sell your car and get a prius

but dont just start turning the cas at random to try and increase anything.

pinging = broken ringlands = rebuild

i found this at the top of forced induction profromace in sticky (quick ref guide)......

OBJECTIVE : Do mid 13's(possibly lower) all day with the standard ecu, intercooler and turbo retained on your R33 gtst.

I used:

A 1995 manual R33 gtst with 93k on the clock.

With the following Modifications:

* K&N panel filter inside stock airbox

* 3inch FGK cat-back exhaust (very quiet and probably more restrictive than some exhausts)

* 3 inch stainless dump pipe off the turbo 'wrapped' with DEI thermal tape to the cat. This dump does not have a sepparate wastegate screamer or feed pipe.

* Diff Cradle kit or 'pineapples' , the Whiteline kit No. KCA349.

* Ogura Lightwieght flywheel 4.8kgs.

* Ceramic puck sprung clutch and stock pressure plate

* Wrapped turbo to intercooler pipe (DEI thermal tape).

* Removed panel behind stock intercooler.

* Timing set around 20+degrees advance.

* disable the carbon canister fume feeds to the intake.

* Turbo smart bleed valve (cheap one) set to 10psi boost

* Simex 205/50 16 inch rear tyres. let them down to 19psi.

* NGK coppers ...6ES gapped to 0.7mm.

no one has said it was a bad thing to advance timing 20+ degrees, has he done the same thing that someone did to my car??

Edited by rich flavour

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Surely somebody has one in VIC. Have you asked at any shops?  Is this the yearly inspection or did you get a canary?
    • This is where I share pain with you, @Duncan. The move to change so many cooling system pieces to plastic is a killer! Plastic end tanks and a few plastic hose flanges on my car's fail after so little time.  Curious about the need for a bigger rad, is that just for long sessions in the summer or because the car generally needs more cooling?
    • So, that is it! It is a pretty expensive process with the ATF costing 50-100 per 5 litres, and a mechanic will probably charge plenty because they don't want to do it. Still, considering how dirty my fluid was at 120,000klm I think it would be worth doing more like every 80,000 to keep the trans happy, they are very expensive to replace. The job is not that hard if you have the specialist tools so you can save a bit of money and do it yourself!
    • OK, onto filling. So I don't really have any pics, but will describe the process as best I can. The USDM workshop manual also covers it from TM-285 onwards. First, make sure the drain plug (17mm) is snug. Not too tight yet because it is coming off again. Note it does have a copper washer that you could replace or anneal (heat up with a blow torch) to seal nicely. Remove the fill plug, which has an inhex (I think it was 6mm but didn't check). Then, screw in the fill fitting, making sure it has a suitable o-ring (mine came without but I think it is meant to be supplied). It is important that you only screw it in hand tight. I didn't get a good pic of it, but the fill plug leads to a tube about 70mm long inside the transmission. This sets the factory level for fluid in the trans (above the join line for the pan!) and will take about 3l to fill. You then need to connect your fluid pump to the fitting via a hose, and pump in whatever amount of fluid you removed (maybe 3 litres, in my case 7 litres). If you put in more than 3l, it will spill out when you remove the fitting, so do quickly and with a drain pan underneath. Once you have pumped in the required amount of clean ATF, you start the engine and run it for 3 minutes to let the fluid circulate. Don't run it longer and if possible check the fluid temp is under 40oC (Ecutek shows Auto Trans Fluid temp now, or you could use an infrared temp gun on the bottom of the pan). The manual stresses the bit about fluid temperature because it expands when hot an might result in an underfil. So from here, the factory manual says to do the "spill and fill" again, and I did. That is, put an oil pan under the drain plug and undo it with a 17mm spanner, then watch your expensive fluid fall back out again, you should get about 3 litres.  Then, put the drain plug back in, pump 3 litres back in through the fill plug with the fitting and pump, disconnect the fill fitting and replace the fill plug, start the car and run for another 3 minutes (making sure the temp is still under 40oC). The manual then asks for a 3rd "spill and fill" just like above. I also did that and so had put 13l in by now.  This time they want you to keep the engine running and run the transmission through R and D (I hope the wheels are still off the ground!) for a while, and allow the trans temp to get to 40oC, then engine off. Finally, back under the car and undo the fill plug to let the overfill drain out; it will stop running when fluid is at the top of the levelling tube. According to the factory, that is job done! Post that, I reconnected the fill fitting and pumped in an extra 0.5l. AMS says 1.5l overfill is safe, but I started with less to see how it goes, I will add another 1.0 litres later if I'm still not happy with the hot shifts.
    • OK, so regardless of whether you did Step 1 - Spill Step 2 - Trans pan removal Step 3 - TCM removal we are on to the clean and refill. First, have a good look at the oil pan. While you might see dirty oil and some carbony build up (I did), what you don't want to see is any metal particles on the magnets, or sparkles in the oil (thankfully not). Give it all a good clean, particularly the magnets, and put the new gasket on if you have one (or, just cross your fingers) Replacement of the Valve body (if you removed it) is the "reverse of assembly". Thread the electrical socket back up through the trans case, hold the valve body up and put in the bolts you removed, with the correct lengths in the correct locations Torque for the bolts in 8Nm only so I hope you have that torque wrench handy (it feels really loose). Plug the output speed sensor back in and clip the wiring into the 2 clips, replace the spring clip on the TCM socket and plug it back into the car loom. For the pan, the workshop manual states the following order: Again, the torque is 8Nm only.
×
×
  • Create New...