timing and boost

[Need for Speed 2]

how many guys are retarding the timing on boosted apexs to run boost. just curiuos i did not retard mine. i have run up to 26lbs for short bursts on 110 octane no problems. plan to run 12psi on premium gas . front mount flat lander not mountain riding, higher speeds with less engine loads. my intercooler is always ice cold even after long pulls.i wondering if intercooler temps are the key to timing retard and deto problems.

 

[Ted Jannetty]

how many guys are retarding the timing on boosted apexs to run boost. just curiuos i did not retard mine. i have run up to 26lbs for short bursts on 110 octane no problems. plan to run 12psi on premium gas . front mount flat lander not mountain riding, higher speeds with less engine loads. my intercooler is always ice cold even after long pulls.i wondering if intercooler temps are the key to timing retard and deto problems.

I start pulling timing after 15 psi boost.

 

[TurboJamie]

I pulled about 4* out of mine at 12 psi.

 

[87gtNOS]

I am of the understanding that idealy you would want to pull timing at lower rpms and perhaps around the torque peak. Otherwise, no need to pull timing at full rpm. Ofcourse, I am not sure if there is a way to do this with the Yammy EFI's.

I get this from my supercharged Mustang days. With a programmer, tweecer? or something, I understodd that the above idea was ideal? Maybe Jannetty can elaborate on this as he is still into the cars....

 

[Ted Jannetty]

how many guys are retarding the timing on boosted apexs to run boost. just curiuos i did not retard mine. i have run up to 26lbs for short bursts on 110 octane no problems. plan to run 12psi on premium gas . front mount flat lander not mountain riding, higher speeds with less engine loads. my intercooler is always ice cold even after long pulls.i wondering if intercooler temps are the key to timing retard and deto problems.

I start pulling timing after 15 psi boost.

What I meant was I don't start pulling timing untill 15 psi boost then I pull about a degree per pound toward 25 psi.
I do this with my MSD ignition which reads boost through a 3 bar map sensor.
I did this to reduce load on stock pistons.

 

[87gtNOS]

how many guys are retarding the timing on boosted apexs to run boost. just curiuos i did not retard mine. i have run up to 26lbs for short bursts on 110 octane no problems. plan to run 12psi on premium gas . front mount flat lander not mountain riding, higher speeds with less engine loads. my intercooler is always ice cold even after long pulls.i wondering if intercooler temps are the key to timing retard and deto problems.

I start pulling timing after 15 psi boost.

What I meant was I don't start pulling timing untill 15 psi boost then I pull about a degree per pound toward 25 psi.
I do this with my MSD ignition which reads boost through a 3 bar map sensor.
I did this to reduce load on stock pistons.

I did similar with the car, MSD Boost Timing Master, pulling with a calibrated dial about 1.5 degrees per # of boost to achieve about 21deg final timing, stock WOT timing was 36deg.

As Ted is using a similar system is nice for the sleds!!

 

[KnappAttack]

Speed 2, Where are you as far as lowering compression?

 

[Need for Speed 2]

mike im at 9.12 or there about, high boost low compression have down falls for trail riding. response go es away. to bad cant find a boost indexed timing controller for efi sleds to trail ride with. ty that into an afr sensor along with deto sensor and i think we would have perfect harmony. we could always acheive max power on any given octane or boost load conditions in general. ok you electronics geniusus i just put in my order ill take 2 please.

 

[KnappAttack]

You don't need to take timing away for 12 lbs at 9.12 comp. Why so low on the comp? Powderlites kit w/ shim is 9.4. I'm planing on 12 lbs at 10.3 comp. ratio with no timing out in the soon to be running CPR attak kit. That is 3 stock .017" gastets for a total of .051" in gaskets.

 

[talldude1]

I have retarded the timing on several turbo yamahas- you wont even notice a decrease in power and it adds a safety margin. you have to slot the holes in the pickup coil or use a timing key- just make sure you go the right direction!! 4 cylinders are easy, 3 cylinders you have to pull the motor!! fun!

 

[BasicBajaX]

how many guys are retarding the timing on boosted apexs to run boost. just curiuos i did not retard mine. i have run up to 26lbs for short bursts on 110 octane no problems. plan to run 12psi on premium gas . front mount flat lander not mountain riding, higher speeds with less engine loads. my intercooler is always ice cold even after long pulls.i wondering if intercooler temps are the key to timing retard and deto problems.

I am probably wrong but if your intercooler is always ice cold doesnt that indicate that its not really doing anything for you. I would think it should be warm or hot if its pulling any kind of heat out of the intake charge. Robert

 

[Need for Speed 2]

the colder the better obvious my intercooler is very eficient inthe conditions im running. ice cold intercooler is as good as ice cold beer.

 

[TWIN TURBO]

I agree with Jannetty! If you understand whats happening in the combustion chamber you would know that boost is raising cylinder pressure's which increases burn speed which decreases the need for timing. Increasing boost, in effect, advances timing which brings one closer to that point where pre-ignition starts which converts very quickly to Detonation and engine destruction. Play it safe and save a motor, retard timing at higher boost levels!