Well spring is upon us and time to get the GTO in shape for summer. Time for a little more surgery.
The latest changes are; headers & hi-flow cats, poly motor & trans mounts, new plugs & wires, oil separator, Harrop diff cover, finally install new rear pads with braided rear brake lines and the Hotchkiss sway bars.
I had a set of JBA long tubes with hi-flow cats but since I am not out for the ultimate power gain and the car is lowered I decided to go the JBA shorty route. I found a local person who had brand new JBA hi-flow cats and JBA shortyās. He is building for all out power so we worked out a trade that benefited us both.
This weekend I completed the all the work at the nose of the car. I soaked all the bolts with aerokroil a day earlier and thankfully all the bolts came out without issue. I wasnāt expecting problems since the car has 45k miles and no winters. Getting the exhaust off was a breeze. On the driverās side I pulled the plugs and that was all; the passenger side I pulled the plugs, coil packs and dipstick. Since I was doing the motor mounts I unbolted them and lifted the engine up a couple of inches. Once the new mounts were in place I put the headers on the heads then lowered the engine back into the k member. All in all, this is a very easy job.
I did backyard engineer the header flange mount, JBA expects you to use bolts. I got some 7/16-14 threaded rod with regular nuts and jamb nuts. This made it super easy to install.
The factory plug wires touch a few of the headers so I ordered some 8.5mm angled boot wires from summit. Once I put them in I can button up the rest of the front.
The hi-flow cats are way bigger that the stock system. The stock system has a 2.5ā flange but the pipe is about 2ā in diameter. The JBA pipe is 2.75ā and does not slim down much. You can see the size difference in the picture. The actual cat on the JBA pipe is way smaller. Iād estimate a 20-25 pound weight savings as well.
I only started the car to check for leaks and swap it around in the garage. I do not want to car too loud so I am still running the factory cat back. First impression is it has a more sinister sound and is only a bit louder. However, the under-hood noise has increased some, in a good way. There is a bit of a kink in the passenger side exhaust where it goes past the diff and into the resonator and I'd assume it is a bit restrictive.
I did notice a bit more harshness with the poly engine mounts but I think it will be OK.
I have the diff cover on but still need to do the sway bar. I plan to work on the rest of the rear later this week. The only thing I havenāt done yet is the front sway bar. I know I must drop the front cradle and I am not sure I want to undertake that yet.
More pictures to come soon as well and some video of the sounds from inside the car.
The latest changes are; headers & hi-flow cats, poly motor & trans mounts, new plugs & wires, oil separator, Harrop diff cover, finally install new rear pads with braided rear brake lines and the Hotchkiss sway bars.
I had a set of JBA long tubes with hi-flow cats but since I am not out for the ultimate power gain and the car is lowered I decided to go the JBA shorty route. I found a local person who had brand new JBA hi-flow cats and JBA shortyās. He is building for all out power so we worked out a trade that benefited us both.
This weekend I completed the all the work at the nose of the car. I soaked all the bolts with aerokroil a day earlier and thankfully all the bolts came out without issue. I wasnāt expecting problems since the car has 45k miles and no winters. Getting the exhaust off was a breeze. On the driverās side I pulled the plugs and that was all; the passenger side I pulled the plugs, coil packs and dipstick. Since I was doing the motor mounts I unbolted them and lifted the engine up a couple of inches. Once the new mounts were in place I put the headers on the heads then lowered the engine back into the k member. All in all, this is a very easy job.
I did backyard engineer the header flange mount, JBA expects you to use bolts. I got some 7/16-14 threaded rod with regular nuts and jamb nuts. This made it super easy to install.
The factory plug wires touch a few of the headers so I ordered some 8.5mm angled boot wires from summit. Once I put them in I can button up the rest of the front.
The hi-flow cats are way bigger that the stock system. The stock system has a 2.5ā flange but the pipe is about 2ā in diameter. The JBA pipe is 2.75ā and does not slim down much. You can see the size difference in the picture. The actual cat on the JBA pipe is way smaller. Iād estimate a 20-25 pound weight savings as well.
I only started the car to check for leaks and swap it around in the garage. I do not want to car too loud so I am still running the factory cat back. First impression is it has a more sinister sound and is only a bit louder. However, the under-hood noise has increased some, in a good way. There is a bit of a kink in the passenger side exhaust where it goes past the diff and into the resonator and I'd assume it is a bit restrictive.
I did notice a bit more harshness with the poly engine mounts but I think it will be OK.
I have the diff cover on but still need to do the sway bar. I plan to work on the rest of the rear later this week. The only thing I havenāt done yet is the front sway bar. I know I must drop the front cradle and I am not sure I want to undertake that yet.
More pictures to come soon as well and some video of the sounds from inside the car.
