Why are 99-00 & 01-02 LS1 VE tables so different?
10-24-2005, 03:47 PM
#1
Why are 99-00 & 01-02 LS1 VE tables so different? I was looking at some stock files using the compare feature in HP Tuner 2.0, and noticed that 1999 & 2000 VE Tables are very different than 2001 & 2002 VE Tables.
Why is this?
These are from a 2000 LS1 F-Body M6:
These are from a 2001 LS1 F-Body M6:
Why is this?
These are from a 2000 LS1 F-Body M6:
These are from a 2001 LS1 F-Body M6:
10-24-2005, 04:00 PM
#2
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99-00 = different cam than 01-02
99-00 = different intake manifold than 01-02
The air flow characteristics are different between them due to the cam and intake manifold changes... amongst other things
99-00 = different intake manifold than 01-02
The air flow characteristics are different between them due to the cam and intake manifold changes... amongst other things
10-24-2005, 04:08 PM
#4
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The most noticeable differences in the VE table you will see in areas that a stock car (or even most modified cars) will ever reach.
GM is not required to build a perfect VE table for every applicaiton.. but instead are required to pass emissions certifications for the calibration itself.. so if the calibration and vehicle combo don't require a certain area of the square VE table, there is no reason for GM to spend extra time fine tuning it... especially when the cars come from the factory with MAF's.
GM is not required to build a perfect VE table for every applicaiton.. but instead are required to pass emissions certifications for the calibration itself.. so if the calibration and vehicle combo don't require a certain area of the square VE table, there is no reason for GM to spend extra time fine tuning it... especially when the cars come from the factory with MAF's.
10-24-2005, 04:34 PM
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IIRC, the '01-02 cams have a bit more overlap than the '99-'00 (hence the stock !egr). So between the cam, !ERG, and ls6 intake, the change seems about right to me.
Would be very interesting to see the difference between a stock SD tuned '00 and '01.
Would be very interesting to see the difference between a stock SD tuned '00 and '01.
10-24-2005, 04:58 PM
#6
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I think he is refering to the decreasing values at higher RPM/MAP. Also, huge drop from 5200 to 5600 rpm in the lower MAP on the 2001 VE. I don't think the cam and intake manifold change is the reason.
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10-24-2005, 08:20 PM
#8
Originally Posted by TAQuickness
If you don't think the CAM and Manifold are effecting the VE, what do you recon it is?
I think it can, but not by that much. It's like a night and day difference.
The cam specs are slightly different, only 1-3 degrees at best in duration. Anyone want to post the cam specs for a 2000 LS1 F-Body and then a 2001 F-body LS1.
Yes, the LS6 intake is better, but do you honestly think it could make that BIG of a difference in the lower RPMs/low load of the VE table? The LS6 intakes biggest advantage is for higher RPM power when you really need to move some air, not at 1,500-2,500 RPMs where the air doesn't have a lot of velocity yet.
10-24-2005, 08:35 PM
#9
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From JRP's sticky
Stock 98-00 trans am cam
Duration@.050 198.86 intake 209.25 exhaust
Lift .498 intake .497 exhausts
LSA 119.45
Stock 01-02 trans am cam
Duration@.050 196.37 intake 208.72 exhaust
Lift .464 intake .479 exhausts
LSA 115.92
https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html
Stock 98-00 trans am cam
Duration@.050 198.86 intake 209.25 exhaust
Lift .498 intake .497 exhausts
LSA 119.45
Stock 01-02 trans am cam
Duration@.050 196.37 intake 208.72 exhaust
Lift .464 intake .479 exhausts
LSA 115.92
https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html
10-24-2005, 08:36 PM
#10
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I need to find the cam doctor sheets for the two cams. they are quite a bit different. the late model cam has a bit more overlap in it
'98-00 Cam Doctor Sheet:
https://ls1tech.com/forums/showpost....84&postcount=6
'98-00 Cam Doctor Sheet:
https://ls1tech.com/forums/showpost....84&postcount=6
Last edited by TAQuickness; 10-24-2005 at 08:43 PM.
10-25-2005, 07:19 AM
#11
Ok, now that we have the specs..
The 99-00 cam has -34.845 degrees of overlap @ .050
The 01-02 cam has -29.295 degrees of overlap @ .050
I still don't believe that 5.55 degrees in overlap difference would justify a night and day difference in the VE tables. From the little bit of SD tuning that I have done, I have noticed that the less overlap you have, the more your VE table "looks" like a 99-00 VE table.
The 99-00 cam has -34.845 degrees of overlap @ .050
The 01-02 cam has -29.295 degrees of overlap @ .050
I still don't believe that 5.55 degrees in overlap difference would justify a night and day difference in the VE tables. From the little bit of SD tuning that I have done, I have noticed that the less overlap you have, the more your VE table "looks" like a 99-00 VE table.
10-25-2005, 07:26 AM
#12
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that's just the .050 specs. I'm searching for a cam doctor sheet on the '01-'02 cams for a better comparison. Seat duration and .200 would give us a much better picture of what's really going on with the cam.
edit:
Also, since we only have the 0.050" specs to eyeball, we have to keep in mind that the "smaller" '01-'02 cam not only puts down the same/similar power as the '98-'00, but also warranted the OEM !EGR.
I don't have my tuning software with me, but I believe if you compare the respective spark tables you will find some differences that effect the VE as well.
edit:
Also, since we only have the 0.050" specs to eyeball, we have to keep in mind that the "smaller" '01-'02 cam not only puts down the same/similar power as the '98-'00, but also warranted the OEM !EGR.
I don't have my tuning software with me, but I believe if you compare the respective spark tables you will find some differences that effect the VE as well.
Last edited by TAQuickness; 10-25-2005 at 07:45 AM.
10-25-2005, 08:25 AM
#13
The '01-02 VE table is more representative of a true speed density tune. The VE graph models the stock torque curve (just as it should). Maybe GM applied the tables they used for the Austrailian Holdens running speed density tuned LS1s. IMO, GM just did a better job on the VE tables for the later year motors...it has little to do with the cam and intake changes.
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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
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
10-25-2005, 09:40 AM
#15
What patrick G said. Early models have that shelf up high because they richen it up till horsepower peak and then they leave it rich. In the later years they did the right thing by richening it up to torque peak and then leaning it back out afterwards. And orange SS is right, They took all our spark away.
