While out on the highway yesterday, I opened it up to see how it would run as I haven't had many chances since the install. It was going like mad until I hit about 5,000 or so RPM, then it seemed to lose power a bit. I got off the highway, and then noticed this raspy sound (brap-brap-brap is the only way I can describe it) whenever I get up to about 3,000 RPM, just before shift revs. Has something happened to my supercharger? Engine sounds fine below 3,000 but then sounds like an exhaust leak over that.
[This message has been edited by NetCam (edited 06-08-2014).]
Using premium gas. Not a pinging, and definitely not a healthy sound. I'm afraid to go over 3K RPM for fear of doing some major damage if it's not already done.
Have a video? What exhaust/muffler do you have on the car? Are you sure it's just not how it's supposed to sound, if you haven't driven it that hard yet since the install?
I'll try to do a video tomorrow. It's never sounded like this before, started immediately after I went WOT on the highway. Strange part was the loss of power as it hit the upper RPM band almost like the SC had cut out.
Are you running it through the stock muffler? I've had one to deteriorate to the point that it sounded like an airplane. The inner and outer layers were apparently banging against one another. Or something. "BRRRAAAP" describes the sound perfectly. Was a real WTF moment when it happened.
If it's making a whole lot of noise, your knock sensor might be picking it up as "knock", and pulling out a bunch of advance.
I'm running a Magnaflow muffler, and it's less than a year old, but you're right, it does sound like a shot muffler, but I can't really see that being the case this early on. I will see if I can get under to have a look just in case, but my jack doesn't do a very good job since I lowered the car. Canadian Tire has a sale starting tomorrow on low profile jacks so I'm hoping to get out there first thing in the morning and grab one.
Listening to it when I'm not driving it does sound like an exhaust leak. Wondering if a place like Midas would put it up on the hoist and look at it for me.
I had a problem like that. It sounded like gravel in the heads around 3,000 rpm when I would tromp on it. Mine turned out to be a loose vacuum hose on the boost line to the fuel pressure regulator. It is actually acting like a rev limiter as it gets starved for fuel.
------------------ Project Genisis Lo Budget 3800SC swap 12.840@104.8 MPH Intense-Racing 1.9 rockers, 3" exhaust, 3.4 pulley, ZZP tune and 18 year old tires. And 31 MPG highway!
My only reccomendation is the probe around with a stethoscope. That little tool is a staple in my box, and really can help pinpoint many mechanical issues.
Checked all the vacuum hoses and can't seem to find anything loose. Scope won't do me any good, because I can't seem to get it to make any noise in the driveway, even if I rev it up to 3K. Seems it will only do it under load.
The sound is now getting worse and worse, to the point I can hear it at idle. I got it up on a hoist and put a scope on it, and it is definitely something internal. Seems to be coming from the number one cylinder, and could be a spun main bearing or connecting rod related. I guess I'm in the market for a new engine......
Actually I did notice the oil pressure was a lot lower than normal. It's always been on the high side, around 400 and today it was probably around 150.
Short video of what it's sounding like now -
[This message has been edited by NetCam (edited 06-13-2014).]
I'm going to take a better look at things on Sunday, but not holding out much hope for this engine. I'll check the oil and look at all the pushrods too.
Actually I did notice the oil pressure was a lot lower than normal. It's always been on the high side, around 400 and today it was probably around 150.
Sounds like bearing noise to me; and if you have noticed the oil pressure has been dropping from where it normally operates, it probably is.
Were the lower intake gaskets on this engine changed recently (within the last 1000 miles or so)?
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