1981 Turbo Trans Am 301 4.9 Dyno

January 2nd, 2020

Happy New Year!

Not something I would normally do, but it was mild weather here in Wisconsin and I thought, why not take the car to the dyno. We have an idea of the power it is making by looking at the 1/4 mile times at the dragstrip.  Mainly the MPH. Let's see what the dyno says this thing makes for HP at the wheels. You can see the video here on my YouTube channel (TTA Performance). All testing was done on a Mustang Dyno at my local machine shop, Don's Auto Parts.


180 HP @ 9 psi of boost and no water injection

208 HP @ 14 psi of boost with water injection.

Pontiac Turbo 301 4.9 Rear Main Seal

April 4th, 2020

The weather finally started to break and the few times I did take the car out, I noticed the rear main seal leak was getting worse. So bad that the whole underneath of the car was covered in oil and it was leaving really large puddles wherever I parked it. I had to address this right away if I was going to enjoy the car at all. I was very hesitant to do this as I wasn't sure I could successfully replace it with the engine in the car. I finally decided to go for it.

At the shop, on the lift and with my BOP Engineering, one piece oil pan gasket and their two piece, Viton, rear main seal at the ready, I dove in. I knew I would have to raise the engine up to get the oil pan out. So, to make sure I didn't have any road blocks in the process, I removed the cooling fan so it wouldn't interfere with the radiator shroud and I loosened the distributor cap in case it tried to come in contact with the firewall. It was a success.  The oil pan came out, the oil pump was off along with the rear main cap. The old rope seal slid out with no issue by grabbing it with a pair of needle nose pliers. The new seal slipped right in with a little force and persuasion. No special tools required. New oil pump was also installed since I was in there and the new oil pan gasket set in place. Since I had the fan off, I decided it would now be a good time to install my two groove water pump pulley to eliminate the AIR pump. I also cut the "ear" off the alternator bracket that the AIR pump attached to for a cleaner look. Had it all done in one day. I was so relieved. No more nasty oil leak.

April 18th, 2020

Today started out good but then things went bad. Not sure what happened exactly, but I have a theory. Let me back track to the weekend prior........

I was out with the car doing a little cruising with my cousin and his 1967 Rambler American Rogue with an AMC 401 and a 4 speed. We were having fun on some county roads in the cool, spring air, but I was noticing I was getting detonation at times when in full boost. I did notice that my boost gauge was showing all of 15 psi, maybe a little more. Water injection was coming on too. But, I have noticed in the past that anything over 14 psi would cause a huge spike in intake temps even with the water injection on, leading to detonation. We later stopped at a gas station and I adjusted the manual boost controller to lower the boost. Detonation stopped and the boost was at 14 psi. Great! It's fixed.

So, fast forward to this weekend. I decide to experiment with a different Quadrajet carb I built and modified to work with both 93 octane pump gas and e85. I install it and tested it with my set up for 93 octane. It ran really rich, so I made some adjustments that seemed to make it better. The family and I took it for a cruise. It was running great. It was pretty rich on full throttle at full boost. After the cruise, I decided to make a small change to the secondary metering rods to try and lean it a little. Took it for another ride. Made my full throttle pull with everything looking good. It never detonated. It never went lean. It didn't overheat. After the pull, I came to a stop and that is when I felt it misfiring and saw all the smoke out the exhaust. I had blown a head gasket. I was able to get it home and that is where she currently sits. My assumption is I compromised the head gasket the weekend before with the detonation and if finally failed. Looks like it is time to set up one of my spare motors with some more mods and swap it in.