Detonation problems...please help
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Detonation problems...please help
Detonation problems...please help
I took my car to Agostino Racing in Pickering, just outside of Toronto to get a dyno tune. Well, Barry Dwyer (dyno guy) took it up to 2500 RPM in 4th and hit it, he backed out of it at around 3300 RPM. "Detonating like crazy" was his response. Jack (Racetronix) was there to adjust the chip. Barry figured that the chip was adding way too much timing, so Jack looked at the chip and said "nope" the chips pretty good, a little lean, but good. So, Jack took a bit of timing out of it, and added a bit more fuel, so now the A/F is at like 12.1 - 12.0. It's still detonating like a ****.
Barry suggested...
Contacting my builder cuz he said it sounded like the compression ratio was way too high. It's 9.5:1 pistons and some head work, and my mechanic figured it should be around 9.5 - 9.75:1 range. He said it sounded like a car he's had worked on before and the ratio was at like 12.5:1.
Checking the distributor for any problems.
Check the MAF (recently replaced - screens and heat sink removed). Replace with stock MAF and check. (I don't have stock MAF anymore - damn!!)
Hook up a scanner and check the knock counts.
Does anyone have any suggestions/similar experiences?
I always thought I heard something different with the engine, like it was under too much load or something, now I know it's detonating.
By the way, my mechanic has the base timing at 4* cuz he said it liked it better at 4 than 6.
Other than that, it seems fine to me, still getting great gas mileage, and now I'm leary to jump on the throttle too much in case of damaging it.
[Modified by black_89_vette, 7:16 PM 10/16/2002]
I took my car to Agostino Racing in Pickering, just outside of Toronto to get a dyno tune. Well, Barry Dwyer (dyno guy) took it up to 2500 RPM in 4th and hit it, he backed out of it at around 3300 RPM. "Detonating like crazy" was his response. Jack (Racetronix) was there to adjust the chip. Barry figured that the chip was adding way too much timing, so Jack looked at the chip and said "nope" the chips pretty good, a little lean, but good. So, Jack took a bit of timing out of it, and added a bit more fuel, so now the A/F is at like 12.1 - 12.0. It's still detonating like a ****.
Barry suggested...
Contacting my builder cuz he said it sounded like the compression ratio was way too high. It's 9.5:1 pistons and some head work, and my mechanic figured it should be around 9.5 - 9.75:1 range. He said it sounded like a car he's had worked on before and the ratio was at like 12.5:1.
Checking the distributor for any problems.
Check the MAF (recently replaced - screens and heat sink removed). Replace with stock MAF and check. (I don't have stock MAF anymore - damn!!)
Hook up a scanner and check the knock counts.
Does anyone have any suggestions/similar experiences?
I always thought I heard something different with the engine, like it was under too much load or something, now I know it's detonating.
By the way, my mechanic has the base timing at 4* cuz he said it liked it better at 4 than 6.
Other than that, it seems fine to me, still getting great gas mileage, and now I'm leary to jump on the throttle too much in case of damaging it.
[Modified by black_89_vette, 7:16 PM 10/16/2002]
Melting Slicks
Joined: Apr 2002
Posts: 3,019
Likes: 0
From: down that one road next to that big tree
Re: Detonation problems...please help (black_89_vette)
what head, head gasket and piston were used? also how much was the block decked? if you feel it's compression run out most of your gas and dyno it on elf 100oct unleaded if it just wakes up and screams you'll know what's going on. my car is right at 11:1 compression on a ed wright chip and it really doesn't run that well on 92. i mean it runs but i can feel the knock sensor killing the timing. just a small amount of octane booster has mine running right. a can of octane booster with each tank & it's running great. i have a 57cc combustion chamber, 4 valve relief flat top piston, a .039 head gasket and i think around 1.3 ccs of deck quench.
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Re: Detonation problems...please help (gtsyellow)
I'm not the most mechanically inclined, so try to bear with me.
I am using the 89 aluminum D port heads that were ported and polished. 58cc I think.
I am pretty sure it has FelPro gaskets (other than that I'm not sure).
The pistons are forged 9.5:1 Keith Black edition hypereutectics.
Block decked--dunno??
I'm running 93 octane and he said it wasn't the fuel. I did ask him, if he thought the compression ratio was too high, why not add some race gas to it. He said it wasn't the ping from low octane, but a detonation.
He did say it wasn't coming from the chip or fuel, but something else.
I am using the 89 aluminum D port heads that were ported and polished. 58cc I think.
I am pretty sure it has FelPro gaskets (other than that I'm not sure).
The pistons are forged 9.5:1 Keith Black edition hypereutectics.
Block decked--dunno??
I'm running 93 octane and he said it wasn't the fuel. I did ask him, if he thought the compression ratio was too high, why not add some race gas to it. He said it wasn't the ping from low octane, but a detonation.
He did say it wasn't coming from the chip or fuel, but something else.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Detonation problems...please help (black_89_vette)
I'm confused on your last post. He said it was coming from somewere else. You mean it could be false knock? Can you *hear* it pinging or are you just seeing it on a computer and feeling it pulling the timing?
Double check the base timing again. Also how do you know what the AFR is? Without a WB or dyno readout whoever or whatever way you are determining 12.0-12.5 is a guess. You may be running WAY lean. This will cause detonation.
Verify these and maybe I can help.
:cheers:
Double check the base timing again. Also how do you know what the AFR is? Without a WB or dyno readout whoever or whatever way you are determining 12.0-12.5 is a guess. You may be running WAY lean. This will cause detonation.
Verify these and maybe I can help.
:cheers:
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Re: Detonation problems...please help (ski_dwn_it)
I'm confused on your last post. He said it was coming from somewere else. You mean it could be false knock? Can you *hear* it pinging or are you just seeing it on a computer and feeling it pulling the timing?
I can definitely hear it. I've been twice, the first time we had no chip guy. We went by ear and knew it was detonating.
Double check the base timing again.
I checked base timing 15 minutes before I drove the almost 3 hour trip
Also how do you know what the AFR is? Without a WB or dyno readout whoever or whatever way you are determining 12.0-12.5 is a guess. You may be running WAY lean. This will cause detonation.
I knew the A/F because he hand a WB hooked up to the exhaust and under WOT it was 12.1 - 12.0. I shouldn't be running lean if it's at 12.0 and have a 255 lph Walbro fuel pump and 30 # FMS injectors.
Verify these and maybe I can help.
:cheers:
I can definitely hear it. I've been twice, the first time we had no chip guy. We went by ear and knew it was detonating.
Double check the base timing again.
I checked base timing 15 minutes before I drove the almost 3 hour trip
Also how do you know what the AFR is? Without a WB or dyno readout whoever or whatever way you are determining 12.0-12.5 is a guess. You may be running WAY lean. This will cause detonation.
I knew the A/F because he hand a WB hooked up to the exhaust and under WOT it was 12.1 - 12.0. I shouldn't be running lean if it's at 12.0 and have a 255 lph Walbro fuel pump and 30 # FMS injectors.
Verify these and maybe I can help.
:cheers:
[Modified by black_89_vette, 6:37 PM 10/10/2002]
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Detonation problems...please help (black_89_vette)
It the pinging at the same point every time or does it move around. Do you have any scans of the events you could send me in excel format?
How much *total* timing is there?
Have you tried octane boost. Although contrary to what most think the octane boost only adds .x to the original octane.
Have you changed spark plugs?
How much *total* timing is there?
Have you tried octane boost. Although contrary to what most think the octane boost only adds .x to the original octane.
Have you changed spark plugs?
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Re: Detonation problems...please help (ski_dwn_it)
It the pinging at the same point every time or does it move around. Do you have any scans of the events you could send me in excel format?
We only tried the 2500-3500 RPM range. He backed off the throttle cuz it was too bad he said he didn't want to do any damage to it. I never took any printoffs of the situation cuz I didn't figure they'd be of any help. I could always ask them to email the runs to me.
How much *total* timing is there?
The chip at the highest (reading from chip guy's computer) is at 33.0 (I think that answers this question, remember I'm a noob, hehe)
Have you tried octane boost. Although contrary to what most think the octane boost only adds .x to the original octane.
I have in the past tried octane boost, but never really felt I got much from it. I always run 93 octane.
Have you changed spark plugs?
The engine has less than 20 000 KM (12 000 Miles) on it since the stock L98 decided to throw a rod and crack the block. I am using plugs with less than 12000 Miles.
We only tried the 2500-3500 RPM range. He backed off the throttle cuz it was too bad he said he didn't want to do any damage to it. I never took any printoffs of the situation cuz I didn't figure they'd be of any help. I could always ask them to email the runs to me.
How much *total* timing is there?
The chip at the highest (reading from chip guy's computer) is at 33.0 (I think that answers this question, remember I'm a noob, hehe)
Have you tried octane boost. Although contrary to what most think the octane boost only adds .x to the original octane.
I have in the past tried octane boost, but never really felt I got much from it. I always run 93 octane.
Have you changed spark plugs?
The engine has less than 20 000 KM (12 000 Miles) on it since the stock L98 decided to throw a rod and crack the block. I am using plugs with less than 12000 Miles.
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Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Detonation problems...please help (black_89_vette)
I would like to see the chip that you are running. Ask them if they can send you the bin file the chip is programmed with. Something is really crapped up.
Did this just start happening after a chip change or has it been doing it since the rebuild of your engine?
Did this just start happening after a chip change or has it been doing it since the rebuild of your engine?
Thread Starter
Melting Slicks
Joined: Nov 2000
Posts: 2,469
Likes: 6
From: Winchester Ontario
Re: Detonation problems...please help (ski_dwn_it)
I would like to see the chip that you are running. Ask them if they can send you the bin file the chip is programmed with. Something is really crapped up.
He modified the Ed Wright chip. I'll call the guy and have him email the .bin file as well as the A/F and the dyno run. although short as it is.
Did this just start happening after a chip change or has it been doing it since the rebuild of your engine?
It's hard to tell. I always thought I heard something wrong but I don't know when it started. I didn't know what I was hearing was detonation. I just thought oh well, I guess this is the way it's supposed to sound. I did notice that before at times it did seem to rev up easier and at other times, including now it seems to have a load on it, and you have to kinda force it a bit more. I wish I was more mechanically inclined cuz I probably woulda noticed it earlier.
He modified the Ed Wright chip. I'll call the guy and have him email the .bin file as well as the A/F and the dyno run. although short as it is.
Did this just start happening after a chip change or has it been doing it since the rebuild of your engine?
It's hard to tell. I always thought I heard something wrong but I don't know when it started. I didn't know what I was hearing was detonation. I just thought oh well, I guess this is the way it's supposed to sound. I did notice that before at times it did seem to rev up easier and at other times, including now it seems to have a load on it, and you have to kinda force it a bit more. I wish I was more mechanically inclined cuz I probably woulda noticed it earlier.
Racer
Joined: Jul 2001
Posts: 399
Likes: 1
From: Toronto Ontario
Re: Detonation problems...please help (black_89_vette)
I agree with 65Z01... I experienced a similar problem. Bought my 88 and experienced mega knock at soon as I bliped the throttle. The ECM readings looked fine. I compression tested it. Try 245 PSI!! That's close to 13:1 compression. The guy was running it on 92 octane gas!! Obviously the guy who build this motor was an idiot. I took the motor apart and found cracked pistons ( from the detonation ) and one with a cracked ring land. They took the motor apart, cleaned out the debris and slammed it back together to unload it. Stay away from a Woodbridge guy called Rolando!!:mad
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: Detonation problems...please help (black_89_vette)
Yes, I would have to agree that something is messed up with the engine configuration. I would take it back to the mech and make them make it right.
If you can get what your cranking compression is, it might help us determine what your static CR is, but it will not be accurate, just a ballpark guess.
You will do damage, or already probably did, if its knocking that bad.
Be sure to document EVERY conversation with the mechanic...incase it gets ugly(court). Good luck.
Send me the stuff I will verify the bin, etc.
:cheers:
If you can get what your cranking compression is, it might help us determine what your static CR is, but it will not be accurate, just a ballpark guess.
You will do damage, or already probably did, if its knocking that bad.
Be sure to document EVERY conversation with the mechanic...incase it gets ugly(court). Good luck.
Send me the stuff I will verify the bin, etc.
:cheers:
