416 LS3 getting dyno tuned, predictions?
10-13-15, 10:10 AM
#1
Senior Member
Thread Starter
416 LS3 getting dyno tuned, predictions?
New engine is getting dyno tuned this week 
Texas Speed built 416 LS3 bottom end, 68cc skimmed L92 heads, ~11.25:1 CR, 229/236 .629"/.615" cam, LS3 intake w/ Samberg over-the-rad snorkel, Hinson midlength headers into two 3" ID Magnaflow metal core cats, Y'd into a single 3" Racing Beat catback.
Mustang eddy current (loading) dyno.
Whaddyall think it will do?
Texas Speed built 416 LS3 bottom end, 68cc skimmed L92 heads, ~11.25:1 CR, 229/236 .629"/.615" cam, LS3 intake w/ Samberg over-the-rad snorkel, Hinson midlength headers into two 3" ID Magnaflow metal core cats, Y'd into a single 3" Racing Beat catback.
Mustang eddy current (loading) dyno.
Whaddyall think it will do?
Last edited by ZDan; 10-13-15 at 10:13 AM.
10-14-15, 04:41 AM
#5
Senior Member
542/487. Most(MOST) of the LS3 based strokers I've seen seem to be a bit lackluster in the peak numbers. Nice tq under the curve though.
My plan some day is a 4.185 bore/3.9 strokeERL/RED block. As much bore as I can on a minimal stroke. Just because it's a little different but not destroked.
My plan some day is a 4.185 bore/3.9 strokeERL/RED block. As much bore as I can on a minimal stroke. Just because it's a little different but not destroked.
10-14-15, 07:01 AM
#6
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I'm guessing it will be more in the 510-530 rwhp range, with 485-495 lb-ft. 542 or 576 would be kick-***! Stock heads, stock intake manifold, and single 3" exhaust, though...
Hopefully will have numbers today!
Hopefully will have numbers today!
10-15-15, 04:16 AM
#7
Senior Member
Ah missed the stock heads... I'm still not sure about how much of a restriction our RB 3" is. I think it would be interesting to see the difference between it and a cutout just in front of the CB just for comparison sake on you motor as it wouldn't matter as much on my 346.
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10-15-15, 08:10 AM
#8
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Thread Starter
Yeah, the basic engine setup is probably good for the numbers you and ZoomZoom posted above, but I think it would take further investment in headwork, a big throttle body, serious intake manifold, long-tube headers, and 3.5" single or dual 3" exhaust out the back, though.
We'll see how it goes soon enough...
We'll see how it goes soon enough...
10-28-15, 04:43 PM
#10
Senior Member
Thread Starter
Was going to wait until I had good backup numbers from a Dynojet, but that might be a while so here's what the eddy-current load dyno spat out:
1st run: 430 rwhp, 421 lb-ft (impossibly low!)
2nd run, with settings modded to mimic Dynojet: 552rwhp, 541 lb-ft (impossibly high!)
Scaling the old engine's 424 lb-ft (Dynojet) torque by displacement and then scaling the new power curves to that, I get 485 lb-ft and 495 rwhp, for whatever that's worth...
Peak is at 6000rpm, right where I wanted it. Glad I followed advice and went with a slightly bigger cam...
I think it is running up against breathing limitations of stock L92 heads, stock LS3 intake and single 3" exhaust.
ANYway, the main idea was to fill in the low-end and midrange and have good street driveability. Honestly the previous 463rwhp power level was more than I could fully utilize at most of the tracks I go to.
Dyno run #1:
Dyno run #2 with parameters modded to simulate Dynojet numbers:
My *adjusted* rwhp and torque for the 6.8 LS3 vs. previous Dynojet results for the old LS2:
1st run: 430 rwhp, 421 lb-ft (impossibly low!)
2nd run, with settings modded to mimic Dynojet: 552rwhp, 541 lb-ft (impossibly high!)
Scaling the old engine's 424 lb-ft (Dynojet) torque by displacement and then scaling the new power curves to that, I get 485 lb-ft and 495 rwhp, for whatever that's worth...
Peak is at 6000rpm, right where I wanted it. Glad I followed advice and went with a slightly bigger cam...
I think it is running up against breathing limitations of stock L92 heads, stock LS3 intake and single 3" exhaust.
ANYway, the main idea was to fill in the low-end and midrange and have good street driveability. Honestly the previous 463rwhp power level was more than I could fully utilize at most of the tracks I go to.
Dyno run #1:
Dyno run #2 with parameters modded to simulate Dynojet numbers:
My *adjusted* rwhp and torque for the 6.8 LS3 vs. previous Dynojet results for the old LS2:
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