General Supercharger Thread

Sniv is the way!

 

Send me your email and I'll send you the datalogging setup I use and then we can go through the logs together, then you can save buying a MPVI if you can. Datalogs can be done and sent to anyone, even if the tune is locked.

 

Ah, f yea. I didn't know that was possible.

 

With @snivilous , anything is possible

 

You guys are making me cringe I'm just here to help, no guarantee it'll work, but I'll do everything I can! And looking at datalogs is minimal effort.

 

I might be dealing with a similar issue AFRs would follow the surging. Throttle relearn fixed it for me before. Truck is in the shop will report back if he sorted the issue out and how.

 

I have some moderate idle oscillating/wandering/surging as well. From my understanding in open mode when you first turn on the Truck the 02 sensors are mostly ignored and the Truck estimates 14.6afr while warming up. Once the Truck believes the 02s are warm switches to closed mode and uses the 02 sensor inputs for fuel/air. This is where the idle issues come into play. In my case I think the main issue is that the long tube headers increase the distance the exhaust gases go. On some vehicles there is a HP Tuners option to change the transport distance. For our vehicles I don’t think there is. I would think if you only had the TVS1900 the stock tune is fine but any changes (injectors/intake/headers/etc) would disrupt the idle some.

There is a setting that defaults usage of LTFT from 450 to 900rpm (at idle) outside that range it becomes like an open loop again. Which I think this is why you will see the rpm gauge often bounce from 450-900ish.

Thus from everything I have seen the way to correct the idle is to data record after the truck is in closed loop. Then dial in the MAF table and other relevant tables for the idle conditions (whereas usually the focus is on WOT conditions etc). Trying to get LTFT close to zero likely will mellow out idle.

 

On @e30cabrio we raised the idle a little since it was doing something similar as I recall and that made the idle lock in better. Correct me if I'm wrong Stefan.

 

Can confirm but may not apply. I had a little surge. Nothing concerning and when I bumped up my idle for when my e-fan comes on it went away.

 

Hmmm... I'm going to remember to try this for an issue that has cropped up for me. That being, when I added a DW adjustable FPR, after startup, the fuel lines would buzz for about a minute or so then stop. I changed back to the stock FPR but then noticed that occasionally it would still happen, just not as pronounced. After poking around a little and thinking about it, it occurred to me that this wasn't happening before my transmission swap. That got me to thinking that maybe that might be a contributing factor, maybe the lines got disturbed slightly and were now slightly freed up a little and a resonance would get set up for a time.

After realizing what I think might be going on, I changed back to the DW FPR again and then the next time I had my cat shields off, I would look at some way to make the lines more secure. Just reaching up and placing my hand on the lines would mute the buzzing. But recently, I've also noticed that after a full warm up, when I've gone out about thirty minutes later to start the truck, when it fires, the rpms would flare as normal, but then it would die. Feeding a little throttle a fraction after the flare is enough to keep it running and then it would be fine on it's own.

How I think I'm going to approach this is to first dial back the fuel pressure from the current 50psi down to the stock 43.5psi, or as near as I can get to it. If that doesn't do the trick, I'll experiment with the tune by adding idle rpms in 5 or 10 rpm increments to see if that resolves it.

Thanks for the idea!

 

Mine specifically feels like the idle is a tad higher than it used to be when sitting.. And then it'll bump up to like 1200rpm and 'push' me through the brakes a bit and then come back down to 1000, which also seems a tad high. Previously the idle was solid as a rock.

 

You made changes that did not fix it, then raised it a bit & all was well.

 

@Ponderosa_Pine I've never had a surge in rpm like that. I do know after getting the MAF and LTFT close to 0 or within 5 of air/fuel it runs pretty well. I just got out of the habit of constantly changing it and giving it time to settle out.

 

Mine wasn't so much surging as dipping to about 700 and coming back to 900 (or so). It was annoying.

lol

 

Yeah mine started when I put long tubes on and it’s not super noticeable, mostly just at like stop lights it will dip down slowly then go back up. My plan is to data log and intentionally let it idle to capture that data (after warm up) to let Sniv see if any corrections can be made there. I usually only drive short distances with this thing so forgot about it haha. Hopefully not a vacuum leak or something.

Oh and going to replace my PCV valve today/check it. Curious if there is any gunk in there. Maybe causing some idle stuff too.

 

It circling around an RPM like that is most likely a bad VE target. Find out what your Lambda is in that area and add or reduce some fuel.

 

Sniv messed with it alot. I'm sure he did all he could.

 

Mine does the same, and I can see the AFR for both banks swinging from rich to lean while it happens, one bank will be rich while the other is lean, and vice versa. The wideband channels look like a double-helix in the logs.

 

Just got done swapping the starter on my '08. That job blows!

If installing a SCer is harder than that job, imma gonna skip installing the fucker on my '21 myself.

I'm definitely using hoses when I install the transmission cooler on the '21. Those rigid transmission cooler lines were a major pain in the ass to work around.

 

It's probably easier
The fuel tank isn't bad as it's made out to be

 

Figured I'd be proactive and tell y'all to go read up on my shit show of a Thursday. It's in the turbo thread.

 

Tough break man, shitty day for sure. Another 5.7 down. If you can stomach the wait time and $$, I'd go XAT for round two

 

Agreed, SC install was easier than the starter.

 

Sorry, bflooks.

That is why I'm replacing the alternator & starter while the motor is coming out.

 

I'm glad to hear this.