Wicked69

Last week I ran my car at the drag strip and it was really loose. The only change I made this week was the trans fluid. I went from Tractor 303 fluid to type F. The car seems to have tightened up. I would have thought it wouldn't have. With the 303 fluid the car wanted to "sliiiiiide" into gear like it was a manual trans and I was slipping the clutch. I went ahead and drained the pan only and put some new Type F in it. Didn't completely pull the trans and convertor, just pulled the pan and let drain for a while. Ended up putting 6 qts back in.

The car drives and sounds the same but just doesn't hit 15lbs of boost. It now only hits 11-12lbs. Would just changing the fluid do this or is something else going on. Both turbo's are spinning, I have the same heat on the exhaust on both sides, plugs look good, car sounds and runs good. Just doesn't hit 15lbs. I have a manual boost controller that is all the way off so I can just turn up the boost controller but just wanted to make sure that a wastegate hasn't failed or something. I have a wastegate on each side and both are getting hot, just like normal. They turn into the atmosphere, not the down pipe.

Not that it would matter but I also changed engine oil from Mobile 1 full synthetic 10W 30 to Valvoline VR1 Racing Oil 20W 50

Thanks.

TermnEatr

iTrader: (24)

That's weird I'm curious to hear thoughts on this bump it up.

dville_gt

iTrader: (5)

that is a big jump, why did you do that?

Wicked69

I probably shouldn't have. I put 1500 miles on it in the last month and a half. When it gets hot after a couple hours of driving I could hear the drive train a little when I opened the hood. I figured the heavier weight oil wouldn't hurt since it was hot out. Now I am thinking I should just change it back. The problem is that I don't know if it is because of the trans fluid change or the engine oil change. The 20w/50 maybe way too thick. If it is I will change it again in the morning before I take it to test and tune. I guess the 5.3 are just a little noisy and I am not used to it. The oil looked perfect when I drained it. Maybe I read too much into the valve train noisy.

Wicked69

FWIW. The oil pressure was fine. 60 cold, 40 hot at idle and 60-80lbs in boost. Probably should have kept the Mobile 1 10w/30 full synthetic.

TermnEatr

iTrader: (24)

It's not just the 5.3 lol stock ls valvetrain is noisy is general. I would put money on the motor oil not the trans .

Wicked69

That's what I am thinking. Especially since stock they run like 5w-20 or something. I'm going to switch it back to see if that free's it up.

98Camarod

iTrader: (43)

I run the 20w 50 as well. I had the mobil1 10w 30 and switched over. I didn't see a decrease in boost, I'm subscribing to see what the problem is.

gregrob

iTrader: (8)

Thinner trans fluid, higher stall speed, less load on engine = less boost...

Combine that with the increased drag placed on the turbo shaft due to the unnecessarily heavy oil weight, and I could see the 3lb drop...