LS1 383ci Pinging LOW TIMING
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Staging Lane
Joined: Nov 2017
Posts: 60
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LS1 383ci Pinging LOW TIMING Hi all, having problems with my new 383 stroker need some advice. I'm getting a fair bit of WOT pinging around peak torque 4700rpm and up with only 22* timing. Also getting a fair bit of throttle tip in knock but that may be another issue. Here are some of the specs on the motor
Ls1 block
4" crank, 3.905 flat tops approx 11.5:1 static comp
Cam is Hydraulic Roller 248/258 112lsa .620 .620 lift
Hand ported 241 heads MLS head gaskets
FAST 102 manifold and 102 throttle body
1 7/8 long tubes and twin 3" exhaust
42lb Bosch green giants, Walbro 255 intank 58psi fuel pressure
NGK tr6 plugs
Premium unleaded 98ron (Australia). I guess that's similar to 92 or 93?
HP Tuners speed density tune
I would think it should take 24-26* with ease but at the drag strip I have had it as low as 19* to stop it pinging. The throttle tip in pinging seems to be a lean spike as I get on the gas so that should be easily fixed. I have tried different brand fuels with the same outcome. Any advice would be great as I am not sure where to start looking. The engine is new with only 3500miles so carbon build up is out of the question. Thanks!
Ls1 block
4" crank, 3.905 flat tops approx 11.5:1 static comp
Cam is Hydraulic Roller 248/258 112lsa .620 .620 lift
Hand ported 241 heads MLS head gaskets
FAST 102 manifold and 102 throttle body
1 7/8 long tubes and twin 3" exhaust
42lb Bosch green giants, Walbro 255 intank 58psi fuel pressure
NGK tr6 plugs
Premium unleaded 98ron (Australia). I guess that's similar to 92 or 93?
HP Tuners speed density tune
I would think it should take 24-26* with ease but at the drag strip I have had it as low as 19* to stop it pinging. The throttle tip in pinging seems to be a lean spike as I get on the gas so that should be easily fixed. I have tried different brand fuels with the same outcome. Any advice would be great as I am not sure where to start looking. The engine is new with only 3500miles so carbon build up is out of the question. Thanks!
Yes but I edited my post, I think I may have had that backwards, It's late here and it's been a long day lol. I think you'll find even adding (mixing in) some race fuel should help.
I run the exact same compression and my timing is limited at 93 octane as well. At one point we ran some E85 and returned it, and I was able to run full timing with no issues
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Did you figure out the pingging issue. I have a question. With the 383 ls stroker kits are you using factory timing for the cam and just adjusting ignition timing or do you have to offset the cam. Im in the process of building one and was curious. Im using a tick towmax stage 2 cam so its nothing real aggressive.
Target Wheel Alignment Hi All, the crankshaft "383 stroker" would have a TW installed by ???
I ask if the TW is a 24xe OR 58x ?
BOTH need to be TDC'd, alignment checked.
Lance
I ask if the TW is a 24xe OR 58x ?
BOTH need to be TDC'd, alignment checked.
Lance
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throttle tip in knock is usually burst knock. Disable it completely in the tune. That should help a lot.
I had a built 6.0 with 11.2 comp and 93 pump. Ran great with 24* timing in it no pinging.
Maybe u got ahold of some bad gas? Good plugs and wires? Verified WOT AFR with a wideband?
I had a built 6.0 with 11.2 comp and 93 pump. Ran great with 24* timing in it no pinging.
Maybe u got ahold of some bad gas? Good plugs and wires? Verified WOT AFR with a wideband?
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Staging Lane
Joined: Nov 2017
Posts: 60
Likes: 1
throttle tip in knock is usually burst knock. Disable it completely in the tune. That should help a lot.
I had a built 6.0 with 11.2 comp and 93 pump. Ran great with 24* timing in it no pinging.
Maybe u got ahold of some bad gas? Good plugs and wires? Verified WOT AFR with a wideband?
I had a built 6.0 with 11.2 comp and 93 pump. Ran great with 24* timing in it no pinging.
Maybe u got ahold of some bad gas? Good plugs and wires? Verified WOT AFR with a wideband?
Don’t get hung up trying to run “x” amount of timing. If it makes great hp and tq at 22 deg and the plugs and data log good then it just wants 22 degs. The same with air fuel, there is no magic air fuel ratio, each engine may like a little different mixture. Your spark plugs, trap mph and datlogs will tell you what your motor wants. We have a Dyno with a eddy brake to load the engine and can get really good data, and good plug readings along with seeing what makes more hp and tq.
Thread Starter
Staging Lane
Joined: Nov 2017
Posts: 60
Likes: 1
Don’t get hung up trying to run “x” amount of timing. If it makes great hp and tq at 22 deg and the plugs and data log good then it just wants 22 degs. The same with air fuel, there is no magic air fuel ratio, each engine may like a little different mixture. Your spark plugs, trap mph and datlogs will tell you what your motor wants. We have a Dyno with a eddy brake to load the engine and can get really good data, and good plug readings along with seeing what makes more hp and tq.
Thanks again
Last edited by toolbag92; Nov 7, 2017 at 12:14 AM.
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From: South Florida
Not much advice to offer. 383 combos always interest me. Couple of thoughts when I looked at your combo. That cam is pretty darn hefty. Duration bigger than a lot of 427s use w/ 29* of overlap. Maybe with a single plane & going to spin a bit although you have the fast on it. You already stated about the cam maybe not being right. I'm no cam guru either. In my opinion the tr6 plugs are a bit cold for a N/A 383. Also what is your exhaust setup after the headers?
Hope you get it sorted out. Just for info I run a 383 with the same compression on pump gas. The only time I remember pinging is when I had the exhaust choked up w/ a y-pipe. Under full load the motor doesn't see much above 24*. Usually a bit under. Pretty mild cam:235/239 116+2. Peak tq at 4800 peak hp at 6550.
What car is this in?
Hope you get it sorted out. Just for info I run a 383 with the same compression on pump gas. The only time I remember pinging is when I had the exhaust choked up w/ a y-pipe. Under full load the motor doesn't see much above 24*. Usually a bit under. Pretty mild cam:235/239 116+2. Peak tq at 4800 peak hp at 6550.
What car is this in?
Thread Starter
Staging Lane
Joined: Nov 2017
Posts: 60
Likes: 1
Thread Starter
Staging Lane
Joined: Nov 2017
Posts: 60
Likes: 1
Not much advice to offer. 383 combos always interest me. Couple of thoughts when I looked at your combo. That cam is pretty darn hefty. Duration bigger than a lot of 427s use w/ 29* of overlap. Maybe with a single plane & going to spin a bit although you have the fast on it. You already stated about the cam maybe not being right. I'm no cam guru either. In my opinion the tr6 plugs are a bit cold for a N/A 383. Also what is your exhaust setup after the headers?
Hope you get it sorted out. Just for info I run a 383 with the same compression on pump gas. The only time I remember pinging is when I had the exhaust choked up w/ a y-pipe. Under full load the motor doesn't see much above 24*. Usually a bit under. Pretty mild cam:235/239 116+2. Peak tq at 4800 peak hp at 6550.
What car is this in?
Hope you get it sorted out. Just for info I run a 383 with the same compression on pump gas. The only time I remember pinging is when I had the exhaust choked up w/ a y-pipe. Under full load the motor doesn't see much above 24*. Usually a bit under. Pretty mild cam:235/239 116+2. Peak tq at 4800 peak hp at 6550.
What car is this in?
Would oil on the plugs be easily noticeable? They look dry and mixture looks good to me. Maybe the cam is just squeezing heaps of air in pumping the dynamic comp up
Last edited by toolbag92; Nov 7, 2017 at 12:17 AM.
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From: South Florida
The car is a 2003 HSV Maloo (Australia) T56 trans 4.11 diff gears. The exhaust is 1 7/8" long tube 4 into 1's, high flow cats, twin 3" cat back with a cross over after the cats. Plenty of flow I would have thought. The cam is huge that's for sure but its mainly a strip car so I was after good top end which it does well. When it was a 5.7l it had a 238/240 112lsa .6xx lift comp XER lobe so I wanted similar manners with the bigger cubes. Its made plenty of power especially with the 241 heads on it still lol aftermarket castings to come in the future. Approx 3930lbs ran 124mph with really low timing (below 20*)
Would oil on the plugs be easily noticeable? They look dry and mixture looks good to me. Maybe the cam is just squeezing heaps of air in pumping the dynamic comp up
Would oil on the plugs be easily noticeable? They look dry and mixture looks good to me. Maybe the cam is just squeezing heaps of air in pumping the dynamic comp up
Oil on the plugs should be noticeable. Unless it's a very tiny amount? As they look dry I wouldn't think excess oil in cylinders is a problem. Do you have any dyno graphs? How high are you spinning her? With that cam I would think the tq peak would be a bit higher in rpm. Maybe something else is dictating that though.
Thread Starter
Staging Lane
Joined: Nov 2017
Posts: 60
Likes: 1
That's an awesome ride! I like those. Exhaust setup sounds good. The only thing I would wonder is the cats. Not saying that is your problem. Just a thought. Def making some power with that mph. Hope you get it figured. Keep us updated.
Oil on the plugs should be noticeable. Unless it's a very tiny amount? As they look dry I wouldn't think excess oil in cylinders is a problem. Do you have any dyno graphs? How high are you spinning her? With that cam I would think the tq peak would be a bit higher in rpm. Maybe something else is dictating that though.
Oil on the plugs should be noticeable. Unless it's a very tiny amount? As they look dry I wouldn't think excess oil in cylinders is a problem. Do you have any dyno graphs? How high are you spinning her? With that cam I would think the tq peak would be a bit higher in rpm. Maybe something else is dictating that though.
I've only run 11.9s in the quarter with 1.8 60ft. Should be able to get 1.6 on the radials a reckon.
Thanks! They are tuff cars for sure. Will have dyno graphs next week some time. It's getting a final look over on the pump fuel tune and a race fuel tune this week. Keen to see the difference. It spins to 7k and peak torque is about 4800 which is where most of the detonation is so I'm thinking its either bad fuel or dynamic comp ratio. Should be a quick car for a manual once its all sorted.
I've only run 11.9s in the quarter with 1.8 60ft. Should be able to get 1.6 on the radials a reckon.
I've only run 11.9s in the quarter with 1.8 60ft. Should be able to get 1.6 on the radials a reckon.
I made one assumption about your cam, since you don't list the advance, I assume it is installed straight up. And i'm coming up with 65cc heads and 0.048" head gasket to get 11.5 CR. Assuming this is even close, your dynamic compression is fine. Even if I artificially push your CR to 11.6, your dynamic compression is only 7.8. if I'm wrong on the advance, and it's, say, +4? your dynamic compression is still only 8.2. 8.5 is safe on your fuel.
I had thought maybe your cam is installed advanced on the timing chain, which would push your dynamic compression really high, but then your peak torque would not be 4800 RPM, so I'm pretty sure the cam is properly degreed.
Here's a couple ideas that might be worth considering:
Try ordering and adding a can of torco octane booster (not the autozone shelf stuff). If that makes it go away, it could point to you having higher compression than what's calculating, which would actually point to a bad timing set, cam ground off, or not quite degreed correctly. I just typically see that cause it to fall on its face and NOT rev to 7K.
If it's going lean specifically on tip in near 4800, and NOT going lean when you tip in at 2500 and ride the RPM band at WOT, that potentially points to transient fuel tables, PE multiplier, or PE delay, which can all be adjusted in your tune.
if you haven't done so, check your fuel pressure with a mechanical gauge just to verify your pressure isn't dropping off at peak demand.