KNOCK RETARD
04-20-2003, 09:29 AM
#1
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KNOCK RETARD
well guys, i took my car to the track today to make a few full passes. definitly not good 
my passes were soooo slow, first full pass was a 16.453 without traction control on, smoked the tires bad and took forever to get into 3 rd gear. second pass was a 15.804 with traction control on just chirped the tires and left, but still very long to get into 3rd gear. there was a guy there with a 98 buick regal that had a SC 3800 in it. he was running 13.89 with it. we talked and came to one conclusion. knock retard from the boost that im getting. hooked a scan tool up and recorded the 3 rd pass. 16.238 and still very long to get into 3 rd gear. got back to the pits and reviewed the data on the scan tool. when in second gear, i had an 8 count on the knock signal.very high.this is killing my times by retarding the timing so far back that its taking almost 100 hp from my motor.does anyone have and suggestions. im going to take the hypertech chip out and run next week and see if that helps. im seriously concidering going with a MSD DIS4 , that way i can set my own timing curve and the amount of timing retard at certain RPM'*. i was running 93 octane fuel with a bottle of racing 104 octane booster in it.
it pulls very well on the pass till just after it gets into second gear, then it just takes forever to build RPM'*. i was even thinking about going to a larger pulley to reduce the boost pressure too.the last pass i made i disconnected the water alcohol injection and it slowed it down 4/10 *. so i really think that its working well. i was even thinking about making a second knock sensor and locate it somewhere that is wont pick up the knock signal and see what it does, and also going to race gas instead of pump gas.
any input would be very helpful on making my mind up on what to do.
thanks.
my passes were soooo slow, first full pass was a 16.453 without traction control on, smoked the tires bad and took forever to get into 3 rd gear. second pass was a 15.804 with traction control on just chirped the tires and left, but still very long to get into 3rd gear. there was a guy there with a 98 buick regal that had a SC 3800 in it. he was running 13.89 with it. we talked and came to one conclusion. knock retard from the boost that im getting. hooked a scan tool up and recorded the 3 rd pass. 16.238 and still very long to get into 3 rd gear. got back to the pits and reviewed the data on the scan tool. when in second gear, i had an 8 count on the knock signal.very high.this is killing my times by retarding the timing so far back that its taking almost 100 hp from my motor.does anyone have and suggestions. im going to take the hypertech chip out and run next week and see if that helps. im seriously concidering going with a MSD DIS4 , that way i can set my own timing curve and the amount of timing retard at certain RPM'*. i was running 93 octane fuel with a bottle of racing 104 octane booster in it.
it pulls very well on the pass till just after it gets into second gear, then it just takes forever to build RPM'*. i was even thinking about going to a larger pulley to reduce the boost pressure too.the last pass i made i disconnected the water alcohol injection and it slowed it down 4/10 *. so i really think that its working well. i was even thinking about making a second knock sensor and locate it somewhere that is wont pick up the knock signal and see what it does, and also going to race gas instead of pump gas.
any input would be very helpful on making my mind up on what to do.
thanks.
04-20-2003, 11:19 AM
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my passes were soooo slow, first full pass was a 16.453 without traction control on, smoked the tires bad and took forever to get into 3 rd gear. second pass was a 15.804 with traction control on just chirped the tires and left, but still very long to get into 3rd gear. there was a guy there with a 98 buick regal that had a SC 3800 in it. he was running 13.89 with it. we talked and came to one conclusion. knock retard from the boost that im getting. hooked a scan tool up and recorded the 3 rd pass. 16.238 and still very long to get into 3 rd gear. got back to the pits and reviewed the data on the scan tool. when in second gear, i had an 8 count on the knock signal.very high.this is killing my times by retarding the timing so far back that its taking almost 100 hp from my motor.does anyone have and suggestions. im going to take the hypertech chip out and run next week and see if that helps. im seriously concidering going with a MSD DIS4 , that way i can set my own timing curve and the amount of timing retard at certain RPM'*. i was running 93 octane fuel with a bottle of racing 104 octane booster in it.
that'* pretty bad.Something is definitely wrong here. You should be into the 14'* with a 0-60 of less than 6 sec'*. :?
It'* definitely a retarded engine.
04-20-2003, 11:29 AM
#3
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lol
pun intended huh lol
i just wrote hypertech to see if they can fix the chip. i also found that the dealer did a prom update on my car too,
they told me that i may have to send it back to them for them to reburn it to my mods.
im not sure, but does the pcm on the SC cars have a boost retard too in the progam too?
im not sure if it does or not.
pun intended huh lol
i just wrote hypertech to see if they can fix the chip. i also found that the dealer did a prom update on my car too,
they told me that i may have to send it back to them for them to reburn it to my mods.
im not sure, but does the pcm on the SC cars have a boost retard too in the progam too?
im not sure if it does or not.
04-20-2003, 06:37 PM
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Are you still running your intake cone like in your picture, without any heat shield or cold air box :?:
Assuming you are, those exhaust headers are radiating 700 F heat and your intake is probably ingesting 150 F temps. That heat will give you knock retard in a big way.
Assuming you are, those exhaust headers are radiating 700 F heat and your intake is probably ingesting 150 F temps. That heat will give you knock retard in a big way.
04-20-2003, 07:00 PM
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Originally Posted by 2000SilverBullet
Woops. 
Just noticed you had the coated manifolds. That probably reduces the temp enough that heat will not be a problem.
Must be the PCM program.
Just noticed you had the coated manifolds. That probably reduces the temp enough that heat will not be a problem.
Must be the PCM program.
04-20-2003, 07:18 PM
#7
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You need to analyze information from the scantool. From your setup, your computer probably has no idea what to do because you are expecting a 10 year old computer to learn and adjust for values that are not very variable. Only in the last few years have modern factory EFI computers been able to learn modifications on their own without retuning up to around 30% horsepower increase.
You are going to have alot of knock retard because you are using an M62 with a very very small pulley and producing alot of psi is not always a good thing. I am sure you your M62 is heated up alot and your water injection can only cool it off so much. If you want to go faster, you have to PORT your heads to get more air in there, the factory heads suck alot. Even if you gasket match the heads, the exhaust ports can be opened up usually 30% larger because they factory makes them small. You are a supercharged vehicle, you need to get air in and more importantly out, so you can fill the cylinder with as much air/fuel as possible. You are going about tuning your car wrong, can't expect to bolt on things and have them work. There is a certain order and sequence you should do. But if you don't want to do the heads, get your computer reburned, that'* what you need more to take advanatge of everything together and have it work in harmony rather than just kinda getting them to work together.
You are going to have alot of knock retard because you are using an M62 with a very very small pulley and producing alot of psi is not always a good thing. I am sure you your M62 is heated up alot and your water injection can only cool it off so much. If you want to go faster, you have to PORT your heads to get more air in there, the factory heads suck alot. Even if you gasket match the heads, the exhaust ports can be opened up usually 30% larger because they factory makes them small. You are a supercharged vehicle, you need to get air in and more importantly out, so you can fill the cylinder with as much air/fuel as possible. You are going about tuning your car wrong, can't expect to bolt on things and have them work. There is a certain order and sequence you should do. But if you don't want to do the heads, get your computer reburned, that'* what you need more to take advanatge of everything together and have it work in harmony rather than just kinda getting them to work together.
04-20-2003, 07:50 PM
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im not sure, but does the pcm on the SC cars have a boost retard too in the progam too?
04-20-2003, 08:35 PM
#9
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after reading the post on the boost solenoid today , i reviewed the data from the scan tool. and there is was, 3 seconds into the run, the boost duty cycle changed bigtime, it was dumping it. also the knock signal was coming from the hypertech chip advancing the timing so far. i wrote them and gave them a list of all my mods, and then removed the chip. they told me before that there was a prom code that had to be in there for it to work properly. i just didnt remember what it was on the e prom when i put it in and just didnt get around to taking the e prom out to see till today. well, the dealer did a prom update on it and it was different than what hypertech tech support told me what it should be. the number they gave me was on the pcm , but the prom had been changed due to a drivability issue as per a GM CAMS update.
also i removed the left front headlight when i ran it, iced the supercharger case a min. of 1 hour before each pass and the coated manifolds are a future mod.
hypertech told me before that if i checked and the e prom was different, that they would reburn the chip to my mods. so i asked them if they can either remove the boost solenoid dump and maybe minimize the kock retard too.
it is sitting here waiting to be sent back to them.
ill keep everyone posted, racing again next sunday with the boost solenoid hose removed from the wastegate actuator and the hypertech chip removed. this should give me more boost and less knock signal from the hypertech timing curve too.
i will definitly post the results next weekend.
also i removed the left front headlight when i ran it, iced the supercharger case a min. of 1 hour before each pass and the coated manifolds are a future mod.
hypertech told me before that if i checked and the e prom was different, that they would reburn the chip to my mods. so i asked them if they can either remove the boost solenoid dump and maybe minimize the kock retard too.
it is sitting here waiting to be sent back to them.
ill keep everyone posted, racing again next sunday with the boost solenoid hose removed from the wastegate actuator and the hypertech chip removed. this should give me more boost and less knock signal from the hypertech timing curve too.
i will definitly post the results next weekend.