Large Cam'd LS1's: Can they cold start and drive immediately?
03-22-2007, 10:00 AM
#21
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Originally Posted by Patrick G
Regardless of temperature, it's possible to have good cold start manners with the right tune. Nailing the VE tables, Open Loop fueling tables and running airflow tables are the keys. Not something you'll typically get with a mail order tune or a 30 minute dyno tune. Tuners would go out of business charging only $500 for the kind of tune necessary to give these kind of street manners. It takes HOURS of data logging to do it right. If you can find someone who will do it right for $500 or less, pay them the money...otherwise, put those funds to buying your own programmer and have fun perfecting the tune yourself! 
03-22-2007, 10:28 AM
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With my MS3 on 15 degree mornings, the car fires right up. It doesnt really want to be driven untill it warms up a bit(minuite or so), but it will with delicate gas and clutch. It idles good on cold start. But drive it to work kill it, and try and restart!? Good luck...
03-22-2007, 11:03 AM
#23
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The reason you let a large cam warm up is not the cam, but the valve springs. Generally, you need stiffer springs with a large cam. The stiff spring is brittle when cold. The spring needs to warm up to become more flexible. You run the risk of breaking a valvespring by driving the car while it's cold.
03-22-2007, 12:24 PM
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I have the Ms4 and I usually start move mine out of the garage or what not right after I start it up. When we had some mornings where it was between 10 and 20 and it started up and found a idle immediatley. you can tell my the exhaust note it's not running to good but never dies or hunts for a idle, just have to be real easy with the clutch to. This is on a TSP mail order tune, it the best mail order tune I've ever got. haven't dyno tuned it as I think it would be a waste of money for what little bit extra I could get out of it.
03-22-2007, 01:02 PM
#25
Originally Posted by PAGregSS
The reason you let a large cam warm up is not the cam, but the valve springs. Generally, you need stiffer springs with a large cam. The stiff spring is brittle when cold. The spring needs to warm up to become more flexible. You run the risk of breaking a valvespring by driving the car while it's cold.
I have to disagree. Valve springs don't have a varying load per se. 1500 RPM is 1500 RPM, whether or not your driving or sitting still.
03-22-2007, 02:09 PM
#28
My last cam Torquer V2+PRC LS6 stage 1s ,A4,3:73. You could go out when there was a heavy frost around 26 degrees and that bitch would fire rite up. No surging,No idle hunting andwhen it was warmed up enough you could hear the cars exhaust change notes and she would rev up 1 time and the settle to a lower 900 rpm idle. Then when you put it in drive you didn't have to worry about giving it more gas the car would taxi itself around at idle with no additional pedal. And that was thru a Vig. 3200 stall. Its all in the tune.
I just bought a new forged 347 shortblock+MS4 on a 111+got Jason to stage 2 my heads. I expect my tuner will have this combo dialed in just as good.
I just bought a new forged 347 shortblock+MS4 on a 111+got Jason to stage 2 my heads. I expect my tuner will have this combo dialed in just as good.
Last edited by NC98Z; 03-22-2007 at 02:15 PM. Reason: Addition
03-22-2007, 03:14 PM
#29
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Originally Posted by 98Birdie
I have the ls1 hotcam without being tuned and it runs good but cold it surges for about a minute and then idles. But, I have to still feather it ti keep it from stalling with the manual when it is cold. It is a bitch on my sloped driveway.
But yeah, it's all in the tune. I've got a 234/236 which is good sized in my stalled automatic. It runs fine on cold starts, only surges a bit when I put it in reverse. But that clears up after about 10 seconds. Once it's warm, no issues at all
03-22-2007, 11:39 PM
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Originally Posted by Beasst8
MS4 and 32 degrees. No probs at all. My hot starts are actually worse than my cold starts. As far as driving it.....Not till its warm.
03-23-2007, 12:41 AM
#32
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Originally Posted by 808ws6
I have a general question regarding large cam'd LS1's.
I have an MS4 cam'd LS1 with a 6 speed.
Is it possible to get the engine tuned so that it can be immediately driven after a cold start without stalling?
I remember 'ol days of pulling the choke which would raise the idle speed and fatten the mixture enough to make the car driveable when cold.
TIA
I have an MS4 cam'd LS1 with a 6 speed.
Is it possible to get the engine tuned so that it can be immediately driven after a cold start without stalling?
I remember 'ol days of pulling the choke which would raise the idle speed and fatten the mixture enough to make the car driveable when cold.
TIA
If it is very cold (below 0-15*F) it does not idle smoothly until it has been running for a few minutes. If I drive very soon after starting in that temperature range I have to put it into neutral if I come to a complete stop and play with the gas pedal to keep it smooth. However, even in the coldest of weather (0-5*) it drives smoothly after a few miles.
It only dies on me about once a year...and is my fault when it does.
03-23-2007, 02:51 AM
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Thanks for all the positive replies everyone!
Can anyone with access to their tune and a successful cold start driveability share your approx. timing, Desired Airflow (g/sec), and VE while in open loop numbers?
I just want to compare with values I have mine set at.
TIA
Can anyone with access to their tune and a successful cold start driveability share your approx. timing, Desired Airflow (g/sec), and VE while in open loop numbers?
I just want to compare with values I have mine set at.
TIA
