Poppster

The first of the noises is from the exhaust. at an idle the car sounds great, however at power it sounds like a jet going by and masks the sound of the engine. (this is according to my Father). Its the stock exhaust on the 99 Formula. however i did just complete a stock lq4 swap and this was on the test run without a solid tune (still Running lean). Does anyone know whats causing this/how to solve the issue?

the second noise, i have posted about in the past but am still having issues with, which is the serpentine belt. All of the Accessory pullies are in good shape, and the ones that typically go bad i have since replaced with no luck. ive played around with adjusting the depth of the balancer and that seems to take care of the issue, however that requires the bolt not be torqued down properly...therefor not safe for anything more than idling. Any others that have had this problem or any with solution ideas your help is greatly appreciated.

SouthernRex

The stock exhaust is too loud? Do you have a leak before the muffler?

RPM WS6

iTrader: (3)

Stock exhaust should be pretty quiet, as suggested above perhaps there is a leak.

Based on your description above, it sounds like the belt noise may be due to pulley alignment. What brackets did you use for the new engine? There was a TSB for belt noise due to the alternator bracket on '98-early '00 cars; the new part relocated the pulley from its original position (and also called for a different idler pulley.) I think the TSB number is 00-06-01-008, should also contain part numbers.

Poppster

My apologies poor wording on the first part. It's not too loud. ( IMO it's not loud enough ) the exhaust makes a whirring sound like the exhaust being forced out of the pipes is being heavily restricted. Similar to an air compressor with a blow gun on it. Just not as loud.

I read about that bulletin and my car is in the Vin range. But I didn't know it required a different pulley as well.

murphinator

iTrader: (2)

stock exhaust trying to flow bigger cubes is my guess on the exhaust noise , throw a catback system on it and I bet you like the sound

Poppster

That was our original thought but I wasn't sure that an extra 20 cubes could cause that.

murphinator

iTrader: (2)

well a stock ls1 with stock exhaust has a bit of that jet/airgun effect - I have one lol but my bolt on cars one with magnaflow catback /ory/kooks long tubes the other with qtp long tubes /x pipe/true duals both sound great - you are going to want a catback anyway start there.

Poppster

Interesting. Well i guess its time to start selling the old parts and buy new ones lol

RPM WS6

iTrader: (3)

The TSB should contain part numbers for both, though they may have changed as that was ~15 years ago. The pulley itself would be easy to obtain, you'd just need to order one from any parts store for an '01 or '02 car as they came stock with the revised design. Not sure if GM still sells the bracket, if not you'd need to locate a used one. The new pulley requires the new bracket to fit properly, so you'd have to get the bracket to make this work.