DCR pump gas sanity check
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DCR pump gas sanity check Will this work well on 93/94 pump gas N/A application? Anybody running similar DCRs with 21* of overlap? I'm looking to get to the ragged edge of pump without having to compromise too much timing up top.
http://img.photobucket.com/albums/v2...ru/dcrcalc.jpg
http://img.photobucket.com/albums/v2...ru/dcrcalc.jpg
Your quench is tight. Your DCR is not too high. Run a cool thermostat and keep an eye on your timing at lower rpm. You should be good to go. Once you get past peak torque, you'll probably be able to crank the timing up towards 30 degrees (if that's what your motor likes). This cam of yours will make some BIG top end power!
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Thread Starter
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From: Kansas City Area
Originally Posted by brad8266
You will be having major PTV issues with that setup. Gas will be the least of your concerns. Hello Mr Piston, meet Ms. valve.
8.7 works on 93 with a good tune.
8.7 works on 93 with a good tune.
Patrick,
That's what I am shooting for. If it makes peak at ~6800 that will be perfect for 135 traps with this 4.10 rear.
Originally Posted by mr2guru
I've already addressed that with -3cc reliefs in the pistons. This is a built 347.
Patrick,
That's what I am shooting for. If it makes peak at ~6800 that will be perfect for 135 traps with this 4.10 rear.
Patrick,
That's what I am shooting for. If it makes peak at ~6800 that will be perfect for 135 traps with this 4.10 rear.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Originally Posted by mr2guru
I've already addressed that with -3cc reliefs in the pistons. This is a built 347.
Patrick,
That's what I am shooting for. If it makes peak at ~6800 that will be perfect for 135 traps with this 4.10 rear.
Patrick,
That's what I am shooting for. If it makes peak at ~6800 that will be perfect for 135 traps with this 4.10 rear.
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Originally Posted by brad8266
That huge cam with 21 overlap and 57cc chambers clears even with 3cc relief?? I have 2cc and a smaller cam and i dont think i can fit 57cc chambers.
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From: Kansas City Area
Originally Posted by brad8266
What the hell is that, i wanna know now!!!
Originally Posted by mr2guru
It's where you fill in part of a 64cc or 72cc chamber with al weld, heat treat, then cnc out the shape to the desired cc. This allows for much smaller chambers without dealing with the problems associated with a lot of milling.
Originally Posted by brad8266
oh ok, thats cool, im gonna go get my mig right now, lol.
I was kidding, i would never use a mig on a head. 
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I'm not sure I trust that DCR Calculator. It says I've got 8.97:1 dynamic (and 11.36:1 static). I'm running 93 octane, 28* of timing, and I went as lean as 15.1:1 in a few cells down in the lower right corner while dialing in the speed density tune, with never more than 2.1* of knock retard.
Last edited by RAACCR; Jan 22, 2007 at 10:43 PM.
Originally Posted by RAACCR
I'm not sure I trust that DCR Calculator. It says I've got 8.97:1. I'm running 93 octane, 28* of timing, and I went as lean as 15.1:1 in a few cells down in the lower right corner while dialing in the speed density tune, with never more than 2.1* of knock retard.
Whats that have to do with the DCR calculator? TECH Apprentice
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Originally Posted by brad8266
Whats that have to do with the DCR calculator?Plug the specs of a stock LS1 into that calculator and it will tell you you've got 10.3:1 static...I think the numbers it gives you are too high. (I think my actual compression numbers are about 3/10 lower than what that calculator is telling me.)
Last edited by RAACCR; Jan 22, 2007 at 10:47 PM.
Originally Posted by RAACCR
Plug the specs of a stock LS1 into that calculator and it will tell you you've got 10.3:1 static...I think the numbers it gives you are too high. (I think my actual compression numbers are about 3/10 lower than what that calculator is telling me.)
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Originally Posted by pianoprodigy
The numbers are correct. Use another calculator with stock LS1 stats and you'll get the same numbers.
It is a nice calculator...I just had my doubts about the numbers it gives. If it is in fact correct, then we may want to re-evaluate the DCR limits that we find acceptable for pump gas. (Current consensus on the board seems to regard the acceptable/desirable pump gas DCR target range around 8.50 - 8.75.) This calc says I've got 11.36:1 static and 8.97:1 dynamic. And, I went very lean in a few cells during tuning with very little knock. During tuning, my worst AFR went to 15.1 with 28* commanded timing, and it only pulled 2.1* knock retard. That being the case, a well tuned motor should be able to tolerate more than 9:1 DCR...maybe alot more?
Not to hijack the thread I think my question apply's when does the size of the cam, overlap and alike influence the DCR to octain formula? My new cam has 246/254 @.050 with .648/.646 lift. my SCR is 11.75 my DCR will be 8.6 surely I will be alot closer to the ragged edge of detonation on pump gas than a milder setup with the same DCR. thats assuming I wont be in trouble I may have to pull alot of timing on my street tune.
Originally Posted by RAACCR
It is a nice calculator...I just had my doubts about the numbers it gives. If it is in fact correct, then we may want to re-evaluate the DCR limits that we find acceptable for pump gas. (Current consensus on the board seems to regard the acceptable/desirable pump gas DCR target range around 8.50 - 8.75.) This calc says I've got 11.36:1 static and 8.97:1 dynamic. And, I went very lean in a few cells during tuning with very little knock. During tuning, my worst AFR went to 15.1 with 28* commanded timing, and it only pulled 2.1* knock retard. That being the case, a well tuned motor should be able to tolerate more than 9:1 DCR...maybe alot more?
Just to be clear, I didn't do any of the calculations in this calculator. J-Rod did the calculations. I merely cleaned it up and made it user-friendly. However, I have compared the results of my calculator with others available online and have come up with the same results.