Wierd sound at WOT
Wierd sound at WOT I have noticed lately that my car sort of sounds like it is breaking up at higher RPMs at WOT. The sound is very hard to describe but it is kind of like a slight popping and it is kind of raspy. My LT1 made this exact same noise when it was missing but I never fixed the problem in it.
It seems to be running good until WOT. It pulls hard and doesnt SEEM to hesitate but it definitely does not sound normal. With windows down it is very noticeable.
I have yet to pull any of the plugs though. I will have time soon.
Any ideas?
It seems to be running good until WOT. It pulls hard and doesnt SEEM to hesitate but it definitely does not sound normal. With windows down it is very noticeable.
I have yet to pull any of the plugs though. I will have time soon.
Any ideas?
I was thinking the same (detonation). I have never heard detonation before so I cant be sure. I run 93 octane 100% of the time! What would cause detonation on this car with only lid, K&N and flowmaster muffler?
No check engine lights either.
No check engine lights either.
does it sound like popcorn popping? i think i may have the same problem.. i cant hear it with the windows down though, all i hear is exhaust and wind. with the windows up i hear a faint crackling though. car still pulls like a son of a bitch though.
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
it's just rasp i'm pretty sure. my exhaust is the dual/dual so there isn't any rasp really, but if i go WOT, when it shifts from 1 to 2 it makes a sound like when a bb hits a soda can. it's just from uneven y pipe lengths from what i've heard, either that or the natural raspiness of an aluminum engine.
Originally Posted by Sunset'01Z
does it sound like popcorn popping? i think i may have the same problem.. i cant hear it with the windows down though, all i hear is exhaust and wind. with the windows up i hear a faint crackling though. car still pulls like a son of a bitch though.
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must be that damn good looking paint job 
well my car runs great (cept for my asp pulley at the moment..
) so i really dont think its too much of a problem. i've put 20k fairly hard driven miles on my car in a year and a half so it's probably something in the engine making noise that is supposed to make noise. and yes, aluminum blocks to resonate more noise than iron blocks do.
well my car runs great (cept for my asp pulley at the moment..
) so i really dont think its too much of a problem. i've put 20k fairly hard driven miles on my car in a year and a half so it's probably something in the engine making noise that is supposed to make noise. and yes, aluminum blocks to resonate more noise than iron blocks do. LS1 Tech Stories
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Originally Posted by Sunset'01Z
must be that damn good looking paint job
What concerns me about the noise is that my LT1 did it also. So it cant be just the alluminum block problem. I am going to do a tune up soon anyway so maybe it will help.
How many miles are on the car? How does it sound at idle normal or off? Whats your oil level like? I'd check your plugs etc. alot of times with just a cracked plug the car can miss and the computer won't pick it up unless its severe enough, it can run absolutely fine with daily driving with a cracked plug, but once you get on it, it begins to show. That'd be my first check, then go from there.
Thanks.
It runs absolutely amazing. No hesitating at all. It has the traditional LS1 shake and shimmy at idle but that is it. MSD wires are on the car already. Like that when I bought it.
Oil just changed, put in M1 0w-40. Valvetrain noisy as hell so I will try another oil next time.
And car has 56,000 miles but it seems to be increasing very quickly
It runs absolutely amazing. No hesitating at all. It has the traditional LS1 shake and shimmy at idle but that is it. MSD wires are on the car already. Like that when I bought it.
Oil just changed, put in M1 0w-40. Valvetrain noisy as hell so I will try another oil next time.
And car has 56,000 miles but it seems to be increasing very quickly
Yea, I'm starting to steer away from M1 brand, if I can find some German Castrol I'll be using that. As for your problem, my bet is on a cracked plug, BUT if the car still pulls well uptop it may be nothing but valvetrain since you mentioned it is noticably noiser than before with that oil.
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
put a whole can of seafoam in your gas tank and run another can through your oil and through the brake booster, half a can in your oil (make sure to change your oil 250 miles later, no more than 500 miles), the other half through the booster. that'll flush out your entire car. if something is clogged, that'll break it loose no doubt and if it's water in the gas tank, that'll dry it right up. good stuff and it's 5 bucks a can. i bet you'll pick up 1-2mpg while you're at it 
TECH Resident
Joined: Jun 2005
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From: Texas
I have the same problem and have been searching this board extensively to try and find out what it is and the only answer I have come up with is this: a lot of people have this problem, no one knows exactly what it is, it usually doesn't effect performance, and we don't know how to fix it (except seafoam, sometimes).
However, wether it hurts performance or not, I would do anything to get rid of it; it sounds horrible(to me, i doubt most people would notice it), and i think the jury is still out on it hurting performance.
I hope someone can enlighten us...
However, wether it hurts performance or not, I would do anything to get rid of it; it sounds horrible(to me, i doubt most people would notice it), and i think the jury is still out on it hurting performance.
I hope someone can enlighten us...
isnt there only one brake booster hose???, im gonna prolly do the seafoam thing the day i do my oil change. seafoam it and then put in the german castrol 0w-30 that i finally found, i want to see if this oil is as great as everyone says it is.
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
Originally Posted by Fire-formula 93
So 1 can of seafoam in the gastank and 1 1/2 cans of seafoam each in the brake booster and oil right? I will utilize the search function I guess. Thanks.
take another can of seafoam. divide it in half.
take the first half and suck about 2/3 of that SLOWLY into the brake booster. don't let the car stall out (make sure your car is warmed up first, don't do this on an immediate cold start). when i did this, i put a small funnel into the brake booster hose and slowly poured it in around an ounce at a time. once that is gone, quickly pour the other 1/3 into the brake booster so the car stalls. if it doesn't stall out, it's fine, just quickly turn off the engine. let it sit for at LEAST 15 mins. start the car up. let it idle for 10 minutes. if it doesn't smoke a lot, GENTLY tap the gas pedal for less than a second. one quick pump up to say, 1300rpms. no need to mash it. a very very gentle bump. that should jumpstart the smoking.
after it has idled for 10 minutes, take her out for hard drive i.e. you better mash this thing a few times. bummer
drive for a couple miles like this.with the last half a can of seafoam, dump it into your ADD OIL tube (directly into the crank case where you add your oil when you change your oil). preferrably dump it in your oil AFTER the engine has sat for a while and cooled off. it's not great to dump room temp seafoam into 200 degree engine oil. it's not the best thing for your valve springs. i'd wait til the next morning to do this part. run the seafoam in your oil for roughly 250 miles, then change the oil. do NOT run it for more than 500 miles with that seafoam in it. your oil will start to gunk up because it frees a LOT of sludge. hell, you may even wanna change it after 100 miles if your oil is black when you change it.
there's my detailed writeup on seafoam. if you have any more questions, PM me or let me know in this thread.