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Sustainability is the reason I went 20 over instead of 30.
I posed the compression reducing question on the LS1 forum and a guy reminded me about "softening" the combustion chamber. I forgot that was a thing and it got me back down the rabbit hole researching squish, flame front, detonation, etc. Looking at things at the micro level down to the fractionth of a second on intake, compression, combustion, it's really complicated. It seems like 20 years ago when I was wrenching on Harleys every day, no one talked about squish or dynamic compression or flame front. But now in the information age, everything has trickled down and I'm behind the power curve here trying to play catch-up.
Anyway I think softening the comb chamber which necessarily increases volume to some degree is a good way to go for what I'm wanting. I'm pretty stoked for everything to come in and start building.
A local transmission shop guy who came recommended by word of mouth said he can build my 4l80 for $2500. I asked him how his build would compare to a Jake's 1,000hp level build and he said call him back monday and we can get into the nuts and bolts of it. The jakes kit I was looking at is like $2,000, it may be worth my while to have someone who knows what they're doing build it for me, if it's comparable. But then I won't get the experience of learning myself (most likely through trial and lots of error). Necessity is often the best teacher.
Had an appointment at the Dyno closest to my house, I need to find another dyno. They wouldn't run it over 100 citing the risk of the driveshaft coming apart. I hadn't heard of this so I googled it and only found one post where this has happened to a silverado, at 130mph. I asked them what I needed to upgrade to be able to do a full pull and they couldn't tell me, "do your research and figure out what you need to do" was their reply.
The guy didn't know how to lock it in 3rd, neither did I so I googled and poked around in VCM scan and found "command 3rd". I couldn't sit in the truck with him so I showed him how to do it and he did a couple 2nd gear pulls and then when he went to do a 3rd gear pull, it kicked back down into 2nd and he said that command 3rd doesn't stop it from kicking down into 2nd. I tried it myself on the highway afterwards and "command 3rd" only let the trans run in 3rd. Even from a dead stop, it starts in 3rd.
Anyway this dyno chart is about worthless. This is a 2nd gear pull, I know that should affect the numbers but I don't know how exactly. And the big nasty spike down low they said was from interference. This dyno doesn't really matter I just want a "before" for a stock motor. I'm assuming it should be laying down somewhere around 275 to the wheels.
Dropped heads off at machine shop. $1200 for port, "softening" the comb chambers, valve job and BTR dual valve springs. He's going to put the comb chambers at 75cc's which should give me 10:1.
He advised upgrading the trunions. Any recommendations?
Then stopped at harbor freight and picked up a sand blast cabinet and a parts washer. And a package of 10mil sockets.
If that dyno graph is from a stock 6.0 in your 2500HD truck, then it's about right, not counting those spikes at low speed. The HD drivetrain eats up the power on these engines.
It would have been more useful to see the chart in RPM instead of speed though.
About 116-117 MPH on the dyno, told the shop that did this - nail down drivability first, then 2nd gear pulls. Nope, goes full send in 3rd gear and damages my truck. Still charged me and never finished the tune. They're out of business now, good riddance.
About 116-117 MPH on the dyno, told the shop that did this - nail down drivability first, then 2nd gear pulls. Nope, goes full send in 3rd gear and damages my truck. Still charged me and never finished the tune. They're out of business now, good riddance.
Nov 3, 2023 | 07:14 PM
