89C4KB
Member
First time Corvette owner and just joined the site last night. I joined because I have a few questions and want to learn. I know next to nothing about Corvettes, other than the fact that I dig them and I’m happy to own one.
I purchased a 1989 Coupe, Bright Red, 42,000 miles, bone stock except for the wheels and exhaust. The car is in great shape, paint is almost perfect, interior super clean, everything works, and the American Racing polished aluminum 5 spoke wheels, so much nicer than the stock wheels. I paid $7k for it (let me know how I did there). I knew the Y-pipe was corroded when I bought it because the previous owner gave me a new Y-pipe, and there were visible holes in the Y-pipe on the car. The car also had Flowmaster mufflers (series 40 I believe).
The car sounded great with these mufflers. It had a grunt that was very pleasing, outside the car. I drove the car home, which was a 1 ½ hour trip. By the time I got home I could not wait to get out of the car and away from the obnoxious droning sound inside.
I figured I would change the Y-pipe out and put the Flowmasters back on to see if the horrible droning was coming from the mufflers or the holes in the Y-pipe. I wasn’t able to do that as the tail pipe to Y-pipe connection was welded (although there were also clamps at the connection deceiving me into believing they were merely clamped on).
I did this the day after I bought the car, and did not want to spend the money on Flowmasters in case that was the source of the droning. I went to O’Reilly’s and bought two Thrush turbo mufflers and some pre-bent exhaust tubing. Went home and welded up the tail pipe and mufflers and installed them, making sure to clamp them to the Y-pipe in case I wanted to change them in the future.
I did not expect much from the two $35 mufflers, however the sound was pretty nice. Not nearly as throaty and mean as the Flowmasters, but still respectable sounding. The sound inside the car was unbelievable, in that there was no sound inside the car. This passed the wife test, which is the most important one.
Amidst my pleasure with the sound, I noticed the throttle response had suffered. There was a noticeable lag when I stabbed the throttle which was not there prior. I deduced this was likely due to the fact there was more restriction in the exhaust having new pipes with no holes in them. I figured I would accept this for the time being as I was only into the new exhaust for less than $100 and a couple hours time, and I need to get a smog inspection before I start messing around with it.
Here is where the confusion comes in. I got in the car the next day and the throttle response had improved substantially. Not back to where it was originally, but noticeably better than the day before. So I start reading forums and I see someone having an issue with something and wanting to reset something else. Someone else posts to run the car at 35 mph for 5 minutes and the whatever will reset itself due to the oxygen sensors correcting the fuel/air mixture.
SO MY QUESTION…Did the throttle response improve because this Tuned Port Injection L98 is a genius of a motor and corrected the mixture, or something else, on its own because there is now more pressure in the exhaust system? Or am I just extremely lucky and should go buy a lottery ticket?
Also on the mufflers, was the droning coming from the holes in the Y-pipe or the Flowmasters?
Any thoughts and/or knowledge would be greatly appreciated by this brand spanking new Corvette guy.
Thanks
I purchased a 1989 Coupe, Bright Red, 42,000 miles, bone stock except for the wheels and exhaust. The car is in great shape, paint is almost perfect, interior super clean, everything works, and the American Racing polished aluminum 5 spoke wheels, so much nicer than the stock wheels. I paid $7k for it (let me know how I did there). I knew the Y-pipe was corroded when I bought it because the previous owner gave me a new Y-pipe, and there were visible holes in the Y-pipe on the car. The car also had Flowmaster mufflers (series 40 I believe).
The car sounded great with these mufflers. It had a grunt that was very pleasing, outside the car. I drove the car home, which was a 1 ½ hour trip. By the time I got home I could not wait to get out of the car and away from the obnoxious droning sound inside.
I figured I would change the Y-pipe out and put the Flowmasters back on to see if the horrible droning was coming from the mufflers or the holes in the Y-pipe. I wasn’t able to do that as the tail pipe to Y-pipe connection was welded (although there were also clamps at the connection deceiving me into believing they were merely clamped on).
I did this the day after I bought the car, and did not want to spend the money on Flowmasters in case that was the source of the droning. I went to O’Reilly’s and bought two Thrush turbo mufflers and some pre-bent exhaust tubing. Went home and welded up the tail pipe and mufflers and installed them, making sure to clamp them to the Y-pipe in case I wanted to change them in the future.
I did not expect much from the two $35 mufflers, however the sound was pretty nice. Not nearly as throaty and mean as the Flowmasters, but still respectable sounding. The sound inside the car was unbelievable, in that there was no sound inside the car. This passed the wife test, which is the most important one.
Amidst my pleasure with the sound, I noticed the throttle response had suffered. There was a noticeable lag when I stabbed the throttle which was not there prior. I deduced this was likely due to the fact there was more restriction in the exhaust having new pipes with no holes in them. I figured I would accept this for the time being as I was only into the new exhaust for less than $100 and a couple hours time, and I need to get a smog inspection before I start messing around with it.
Here is where the confusion comes in. I got in the car the next day and the throttle response had improved substantially. Not back to where it was originally, but noticeably better than the day before. So I start reading forums and I see someone having an issue with something and wanting to reset something else. Someone else posts to run the car at 35 mph for 5 minutes and the whatever will reset itself due to the oxygen sensors correcting the fuel/air mixture.
SO MY QUESTION…Did the throttle response improve because this Tuned Port Injection L98 is a genius of a motor and corrected the mixture, or something else, on its own because there is now more pressure in the exhaust system? Or am I just extremely lucky and should go buy a lottery ticket?
Also on the mufflers, was the droning coming from the holes in the Y-pipe or the Flowmasters?
Any thoughts and/or knowledge would be greatly appreciated by this brand spanking new Corvette guy.
Thanks
ad
