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LS3 Carbed build

General engine tech -- Drag Racing to Circle Track

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CGT
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Re: LS3 Carbed build

Post by CGT » Sun Feb 02, 2020 9:37 am

20200202_074416.jpg
20200202_074428.jpg


"Blue" on these sheets indicate the Late Mode Plus fuel.
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Re: LS3 Carbed build

Post by RevTheory » Sun Feb 02, 2020 10:14 am

Nice work, dude =D>

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Re: LS3 Carbed build

Post by D.B.O. » Sun Feb 02, 2020 10:26 am

What carb jetting, bleed sizes did you have baseline vs. Q16?

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Re: LS3 Carbed build

Post by CGT » Sun Feb 02, 2020 10:30 am

D.B.O. wrote:
Sun Feb 02, 2020 10:26 am
What carb jetting, bleed sizes did you have baseline vs. Q16?
It is an 8896 1050 that Mark Whitener converted to 2 circuit with some quickfuel blocks I had and quickfuel boosters. It had 85 Holley jets all 4 corners on Late Model fuel. I put 89's in it for the Q16 pulls.

I havent touched a bleed in it. The carb, blocks, and boosters were stuff I just had laying around. Mark did a great job of making it all work. I can look at bleed sizes for you if you want..But that will be tomorrow when I pick my stuff up.
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Re: LS3 Carbed build

Post by steve cowan » Sun Feb 02, 2020 1:01 pm

CGT wrote:
Sun Feb 02, 2020 9:30 am
Well, been looking everything over. Cam 2 is a better cam...in this engine anyway. It's down a bit or equal to cam 1 below 6200 but is better after that. It is 10 or 15 better on average after 7000...and is smoother, more consistent up there. It appears to keep the valvetrain more stable. Same lobe families, so think about that one for a minute.

We did a few pulls on Q16, and the pull on the videos was one of those. The best pull on Q was 763hp and 560 torque, I'm not convinced at all that it has peaked yet. The best pull on the Late model plus fuel was 758hp and 550 torque. Just noticed, I have 59 pulls on this thing already :lol:

New vacuum pump seems fine, the Schumann ER oil pump system did not change the oil pressure issue in any way that I can tell...other theories are evolving :P So that was a bit upsetting. Probably won't be the last 500.00 I will light on fire :oops:

Biggest hp gains from the 2 day session.... the decision to turn the engine higher.
i think it just proves that valve events only work in a narrow set of parameters like rpm,engine load etc.
valves dont only float at peak rpm.
not sure if you are using same valve springs as before?
is it possible that spring rate and cam worked in better sync at higher rpms :D
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Re: LS3 Carbed build

Post by CGT » Sun Feb 02, 2020 3:01 pm

steve cowan wrote:
Sun Feb 02, 2020 1:01 pm
i think it just proves that valve events only work in a narrow set of parameters like rpm,engine load etc.
For sure. The "perfect" cam if there is such a thing, can only be for a snapshot at a time through a given range. The wider the range your operating in, the more this becomes evident. And cam position can be like that also...until you get enough of the events out of whack that it just gives up everywhere :shock: ....I think itd be pretty easy to make a solid roller better from start to finish on this this thing though, but im sure that could be humbling.

Cam 1 ran the best as far as averages at about 108ICL, and Cam 2 around 107ICL(I say "around" because its a hex adjust, if youve had experience with them lol) I backed cam 2 up to around 111 and it hurt power from 5000 all the way to 8200. Cam 1 and 2 in the positions that produced the best average power had nearly the same IVC in common..

I pretty much got all my tests in that I wanted except the low viscosity synthetic oil. I didn't have the balls to put thin oil in it with the hydraulics and 8200 rpm stuff.
steve cowan wrote:
Sun Feb 02, 2020 1:01 pm
is it possible that spring rate and cam worked in better sync at higher rpms
Randy brought up a good point about cam 2. Same lobe family, same lobe lift....longer duration(cam 2) should be slightly tamer...and that could be responsible for how things smoothed out some up above 7000.

But im looking at my 4-1 header test now and its considerably smoother up there also, which could mean something is going out of tune up there with the try y's. Or that since the 4-1's were down on power it just looks smoother because there is less power on either side of the zigs and zags. 8).....more questions...
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Re: LS3 Carbed build

Post by MadBill » Sun Feb 02, 2020 9:48 pm

CGT wrote:
Sun Feb 02, 2020 3:01 pm
Cam 1 ran the best as far as averages at about 108ICL, and Cam 2 around 107ICL(I say "around" because its a hex adjust, if youve had experience with them lol)..
One advantage of mechanical distributors, the timing light will tell you exactly how far you moved the cam. :)
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Re: LS3 Carbed build

Post by randy331 » Mon Feb 03, 2020 1:09 am

steve cowan wrote:
Sun Feb 02, 2020 1:01 pm
CGT wrote:
Sun Feb 02, 2020 9:30 am
Well, been looking everything over. Cam 2 is a better cam...in this engine anyway. It's down a bit or equal to cam 1 below 6200 but is better after that. It is 10 or 15 better on average after 7000...and is smoother, more consistent up there. It appears to keep the valvetrain more stable. Same lobe families, so think about that one for a minute.

We did a few pulls on Q16, and the pull on the videos was one of those. The best pull on Q was 763hp and 560 torque, I'm not convinced at all that it has peaked yet. The best pull on the Late model plus fuel was 758hp and 550 torque. Just noticed, I have 59 pulls on this thing already :lol:

New vacuum pump seems fine, the Schumann ER oil pump system did not change the oil pressure issue in any way that I can tell...other theories are evolving :P So that was a bit upsetting. Probably won't be the last 500.00 I will light on fire :oops:

Biggest hp gains from the 2 day session.... the decision to turn the engine higher.
i think it just proves that valve events only work in a narrow set of parameters like rpm,engine load etc.
valves dont only float at peak rpm.
not sure if you are using same valve springs as before?
is it possible that spring rate and cam worked in better sync at higher rpms :D
It's really what would be expected from a cam change like this was. Bigger cam and it's a little better up top but down or the same down low.
If you haven't added lift or sped the valve motion up you just won't see big differences from a few deg cam change, especially if you move both cams around for best power like was done with this cam test.

I knew the induction tract on 377 cubes would want to peak up high. Be interesting to see just how high with a nice solid roller,... but I can see not wanting to turn the stock bottom end any higher. :D

Now I'm starting to wonder how hi this lsx 454 I'm doing will want to peak ?? LOL

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Re: LS3 Carbed build

Post by CGT » Mon Feb 03, 2020 9:01 am

randy331 wrote:
Mon Feb 03, 2020 1:09 am
Now I'm starting to wonder how hi this lsx 454 I'm doing will want to peak ?? LOL
Well if that thing peaks at 7000, it's gonna make good power.
ls7.jpg
This may be your obstacle ^^^^^
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Re: LS3 Carbed build

Post by steve cowan » Mon Feb 03, 2020 11:27 am

I calculated that 454 will peak around 6500 with 2.8" average CSA but Randy advised me it was a bit bigger so I think it will be close to 7000 rpm.
I just reread thread looking for valve seat angles used 52-55 deg
With the tri -y headers I thought there might be some overscavanging at high rpms but I don't think that's the case, I read a while back that C Elston doesn't recommend using a 4-7 swap firing order with tri-y headers but I can't verify a LS firing order??
Chad
Your comment on your engine might not have hit peak yet left me wondering but now I see your CSA from plenum / runner entry and port CSA to throat area( Min CSA)
I can see how the engine probably has not given all its got for the cubic inchs lol.
Was wondering if your new vac pump was replaced under warranty??
This is a excellent thread and after reading again there is some great information :D
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Re: LS3 Carbed build

Post by CGT » Mon Feb 03, 2020 11:51 am

steve cowan wrote:
Mon Feb 03, 2020 11:27 am
firing order with tri-y headers but I can't verify a LS firing order??
18726543 4-7 2-3 swap
steve cowan wrote:
Mon Feb 03, 2020 11:27 am
Was wondering if your new vac pump was replaced under warranty??
Yes, GZ actually overnighted me a completely new one, upon receiving my original.
steve cowan wrote:
Mon Feb 03, 2020 11:27 am
With the tri -y headers I thought there might be some overscavanging at high rpms but I don't think that's the case, I read a while back that C Elston doesn't recommend using a 4-7 swap
This is 2 LS engines now I've tested these goofy looking try-y's against a nice set of 4-1's. Same result both times, they were better from start to finish. The other engine was 429 CI ls7. By looking at the 2, you'd swear the 4-1's would have to run better...at least up top...nope. Exhaust stuff is humbling.
steve cowan wrote:
Mon Feb 03, 2020 11:27 am
I calculated that 454 will peak around 6500 with 2.8" average CSA but Randy advised me it was a bit bigger so I think it will be close to 7000 rpm.
I bet Randy will find a way to make it peak there if that's what he wants.
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Re: LS3 Carbed build

Post by GARY C » Mon Feb 03, 2020 11:54 am

randy331 wrote:
Wed Jan 29, 2020 12:00 am
CGT wrote:
Tue Jan 28, 2020 8:59 am
20200127_215439.jpg

New cam on the left. Old cam on the right. Most likely not much change...ill find out.
Is one of them speced with flowZ ?

Here's a thread you may want to read before ordering a 3rd cam. Talk of pros n cons of using flowZ to spec cams. :D
viewtopic.php?f=1&t=59855

Randy
Using the flowz posted and guessing at the rest here is what I come up with at the valve for cam 3 but the lift would require solid roller. :)
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Re: LS3 Carbed build

Post by RevTheory » Mon Feb 03, 2020 12:02 pm

It won't let me open it, Gary. Is it pretty close to what Chad came up with?

Edit: Nevermind. It opened and it's pretty interesting.

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Re: LS3 Carbed build

Post by GARY C » Mon Feb 03, 2020 12:05 pm

RevTheory wrote:
Mon Feb 03, 2020 12:02 pm
It won't let me open it, Gary. Is it pretty close to what Chad came up with?

Edit: Nevermind. It opened and it's pretty interesting.
I was editing so that maybe why, I screwed up on the first one. (LOL...Lots of Lift :) )
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Re: LS3 Carbed build

Post by RevTheory » Mon Feb 03, 2020 12:18 pm

Surely someone makes a .531 hyd/roller lobe :lol:

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