Head scratcher

[L31MaxExpress]

Drove it around for about 1 hour earlier. Rolled into it from about 20 mph getting on the highway on an uphill ramp. It grabbed 1-2 then not long after 2-3 at 5,500 at full throttle and was rolling along when I let off before I even hit the end of the ramp. Definitely making better power now with the clogging 2.5" cats removed, continuous 3" pipes to the muffler and new plugs that are the proper reach in it. When it cools down here in a little while, time for the oil seperator that showed up while I was gone and the new 4" MAF housing to replace the junk Spectre one that I put a ~2010 LS MAF in its place at the time to get installed. I am going to use the 1/2 hose fitting where the EGR tube goes on a stock intake for the vacuum souce and cap off the one in the marine lid. For being a $35 catch can this one is as nice or nicer than some of the over priced $150-200 name brand ones.

I am headed out to my mom's house to do some yard work and other stuff. Probably just end up driving it. 100 miles there and 100 miles back. Perfect for some datalogging and re-tuning.

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[0xDEADBEEF]

Does the catch can have media in it? If so, be damn sure it can't get out! Cheap cans have destroyed motors with what looks like coarse steel wool for media that got loose.

 

[L31MaxExpress]

Does the catch can have media in it? If so, be damn sure it can't get out! Cheap cans have destroyed motors with what looks like coarse steel wool for media that got loose.

Optional to put it in.

 

[0xDEADBEEF]

Optional to put it in.

Don't! Can't remember where, but it cost someone a motor on a forum I was on.

The Mishimoto can I run on my C8 has a sintered bronze filter in it, might be a cheap upgrade to the can.

 

[L31MaxExpress]

Catch can mounting location. Took a break to grill some burgers.

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[L31MaxExpress]

Found a substantial vacuum leak too in all this. The rubber cap I had clamped over the 1/2" fitting on the intake had a split in it. No idea how long it has been like that since it is practically obscured from view but apparantly it was there during previous tuning. I replaced that cap with the 1/2 hose to the catch can, plugged off the 3/8" PCV port in the manifold lid with a nice silicone cap I had laying around and my fuel trims are now at -18% at idle on both banks so that leak was fairly substantial. Result is it is now running even smoother.

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[SNCTMPL]

I added a high flow catch can to my Duramax, it has about a quarter cup every oil change. That’s a quarter cup not going to the turbo.

On the 383 we’re building my son I just bought some Total Seal gas ported rings, they are supposed to really cut down on blow-by, we’ll see.

I thought I had a picture of the catch can, but apparently I only take pictures of my son’s truck these days.

 

[L31MaxExpress]

4" LS7 style maf tube installed, running great on the GM MAF curve from a GM 525 HP LS3 crate engine. Also figured out the closed loop Integrator delay was far too long and the proportional fuel was way to high . Ended up playing around with it and cut both in half. The AFR stays much closer around stoich and the engine is so much smoother and snappier now at part throttle. The tip-in lean spot I was seeing in closed loop since forever in this van is GONE now too since playing with the integrator delay and proportional fuel settings. More on that later. About to get a good 30 minutes of data recorded driving it around. Really need to work on the VE tables again now that everything is corrected.

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[L31MaxExpress]

Took it on a 20 mile test drive, about half and half highway and city stop lights and stop signs, etc. Fuel economy is showing a marked increase compared to the same drive the other day when I was working on the transmission re-tuning. The fairly accurate estimate I have setup in the math in the HPTuners scanner was showing 15.4x until I caught an extremely long traffic light that changed right as I was getting to it and had a police officer sitting at it on my right, I did not want to enter it on yellow and catch the red before I was through it and stopped. Dropped to 14.82 after that excessively long light. That screenshot was rolling 75 mph on a flat section of the express tollway they dumped us on because of construction on the main highway, free 3-4 mile high speed run on the tollway. People already on it flying and I had to really get it to match the speed of traffic to get on it, hence the tracer marks on the speedo and tach, lol. Same drive the other day resulted in 11.12 mpg on the same run. That is when I knew something was actually wrong.

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[L31MaxExpress]

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