Why 6200 rev limiter for the LSA engine?
#1
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If the cylinder heads in the LSA engine shares its valvetrain components with the vette LS3 cylinder heads, why did GM limit its rev to 6200rpm vs the vette's 6600 rpm rev limiter?
The LSA specs shown in GMPP catalog shows a 6600 as max recommended rpm
![](http://i113.photobucket.com/albums/n227/Khaled_AlHousani/LSAenginespecs.jpg)
Besides, New Era Performance took a stock LSA to 6600 rpm and the power continues to go up
![](http://i113.photobucket.com/albums/n227/Khaled_AlHousani/09ctsv-intaketune.jpg)
Does anyone know any info why the LSA engine rev limiter is set at 6200 rpm? Is GM too conservative here?
The LSA specs shown in GMPP catalog shows a 6600 as max recommended rpm
![](http://i113.photobucket.com/albums/n227/Khaled_AlHousani/LSAenginespecs.jpg)
Besides, New Era Performance took a stock LSA to 6600 rpm and the power continues to go up
![](http://i113.photobucket.com/albums/n227/Khaled_AlHousani/09ctsv-intaketune.jpg)
Does anyone know any info why the LSA engine rev limiter is set at 6200 rpm? Is GM too conservative here?
#2
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GM certified the LSA @ 556 fwhp @6100 per the SAE tests they are required to do. They achieved their 550 fwhp goal. Sure there is more in the engine, but it should live longer with a 6200 rpm redline than a 6600 as the loads are considerably less @ 6200. I suspect that the engine, valvetrain, etc. is stable to 6600.
The marine version of the LSA-SC is rated at 530 fwhp (or 540 depending on when the numbers were published) at 5400 with a fuel cutoff @5600. Marine engines are normally tested with fewer accessories than cars and with freer exhausts. As you can see in the link, power certainly hadn't peaked @ 5400. I make it ~550 at 5600. Boats are much harder on engines than cars. The run at high load, high rpm for long periods of time. It's hard to run uphill at 150 in a CTS-V for an hour or more at a time.
http://www.gm.com/experience/technol...LSA_Marine.pdf
The marine version of the LSA-SC is rated at 530 fwhp (or 540 depending on when the numbers were published) at 5400 with a fuel cutoff @5600. Marine engines are normally tested with fewer accessories than cars and with freer exhausts. As you can see in the link, power certainly hadn't peaked @ 5400. I make it ~550 at 5600. Boats are much harder on engines than cars. The run at high load, high rpm for long periods of time. It's hard to run uphill at 150 in a CTS-V for an hour or more at a time.
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http://www.gm.com/experience/technol...LSA_Marine.pdf
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http://reviews.carreview.com/blog/ch...orvette-zr1/2/
http://www.media.gm.com/us/cadillac/...CTSVindex.html
LSA has 1.9L blower and a single brick IC, LS9 has a 2.3L blower and a dual brick IC as noted above.
Design goals were 620 hp for the '9 and 550 for the 'A. Generally the "platform people" (those responsible for the overall car) decide how much power/torque they need and Powertrain people deliver that.
If the Camaro ever gets the SC engine, my bet is the LSA, not the LS9.
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#9
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I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
#11
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You didn't like my previous explanation of that, I guess.
I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
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You didn't like my previous explanation of that, I guess.
I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
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Besides, New Era Performance took a stock LSA to 6600 rpm and the power continues to go up
Does anyone know any info why the LSA engine rev limiter is set at 6200 rpm? Is GM too conservative here?
Last edited by DrkPhx; 04-11-2009 at 08:54 AM.
#14
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You didn't like my previous explanation of that, I guess.
I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
I'll make it more explicit: The Old Farts (OF) that buy CST-Vs have slow reaction times, so when they try to shift at 5600, they finally get the shift done about 6100. Hence the 6200 fuel cutoff. If GM let us old guys have 6600 we'd probably be in the warranty shop all the time.
Now, what did they do to prevent us OFs from downshifting from 5th to 2nd when we were trying for a 5>4 shift and overreving the urine out of the LSA? They use a Dealer-Only (DO) hidden function in the PCM called RSSPA (Reverse Skip-Shift Prevention Algorithm). It is pronounced "riss=pah", the sound remarkedly similar to an OFs sound when he breathes, and is activated by the dealer before delivery of a CTS-V to anyone over the age of 60. LSAEdit can bypass it however.
Does that clear things up?
Jon
Thanks, man.
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#15
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Same rev limiter in the upcoming ZL1. Would you say it's "safe" to increase the rev limiter of this engine to 6600 rpms or so? Just as safe as say, the ls3 or ls9? Or is there something about the LSA that makes it a bit more risky to rev as high as its 6.2liter siblings?
#17
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In the wait4me canned tune on a SCT handheld he raised the shift points to 6,400. Because of the heavier valves in the LSA (compared to the LS9), he doesn't recommend going higher without stronger valve springs and pushrods.
#18
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Is that all that's holding it back? I thought it had something to do with the cast pistons. The LS9 has forged pistons. I thought the valve train was the same on the LSA and LS9?
#19
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Different valves, titanium Vs steel intake, steel Vs hollow stem steel. LS9 valves much lighter. Cams are different, don't know if the springs are the same.
#20
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Also the max shift speed of the 6l90 used in the CTSV is 6200RPM's I would suspect thats the real reason as the 6l80/90 doesn't like RPM's higher than that.
That would explain the the auto units as for the manual cars are the limited the same?
That would explain the the auto units as for the manual cars are the limited the same?