Dynamax Exhuast

[Shawn T]

Wow, it has been a long time since I have been on this site. At a new job and it's finally not fire walled. On my 60 duramax LBZ I installed a poor man's turbo back exhaust. I just cut the cat off and replaced the stock pipe and muffler back. I went from the stock diameter pipe (3 inch, i think) into the dynamax 12" muffler and out 4" with a 5" tip. When accelerating hard and at high RPM's it sounds like it's gasping or whistling from the intake. My filter is clean and it's done it ever since installation. Is it because I didn't go with 4" all of the way from the turbo back? Also, when pulling a trailer on high altitude climbs and hilly terrain, I get an SES light for about 2 days and then it resets on it' own. I'm assuming this is a low back pressure issue. Does anyone else who has modified thier exhaust get this?

Thanks in advance

[plowking]

What you hear is the turbo spooling up. It is more noticable with a less restrictive exhaust and/or an aftermarket air intake. You can really hear it on big rigs,especially when they are pulling a hill. If you have been working your truck hard,it's a good idea to let it idle some to let the oil cool the bearings on the turbo unless you have been driving at slower speeds near your destination. The average consumer doesn't want to hear turbo,other sounds,so baffles on intake,air cleaner shroud,exhaust system stop the whistle. If your truck developed a whistle with stock exhaust, intake, then you would check the clamps,hoses,connections on the turbo to intake,exhaust,usually in that case you would be down on power. I'm not sure about your SES light,maybe have someone hook up a OBD11 scan tool and check the codes plowking

[Shawn T]

It's not turbo whistle. It's more a "whoosh" sound. Like air traveling through a venturi or something. I still have the stock intake so the whistle is relatively the same. Under hard acceleration it almost sounds like the intake is being restricted in a way. More of a gasping sound. Would this be a risky thing to do?: Remove the air cleaner and just run it down the road far enough to open it up and see if it's still making the same noise.