Need help selecting a camshaft and supporting modifications for my 08 LS3 Corvette
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Teching In
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With the fast on there you may pick up a few hundred rpm just from an increase in airflow alone. Keep in mind that as you raise peak hp up, your idle and low rpm torque will suffer. I wouldn't go over a 230 duration with the goals you have for the car. Bigger cams will drive fine, but you want a stock like idle and you aren't going to get that with a bigger cam.
Last edited by Brasil; Feb 16, 2009 at 04:40 PM.
My initial response would be nope...800rpm is too low IMHO. I'm sure it can be done with a lot of idle air work for cold and hot idle but I'd same a better goal would be 850+ for a target idle rpm. I can tell you my cam didn't like 800rpm's idle speed at all!
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I just worked on a G8 today with the XER273HR in it and it idled fine at 700rpm. Could have gone lower and in fact had it lower initially. Only raised it to take some of the chop away. It just takes a good amount of tuning to get a normal idle out of them. With your extra cubes and compression you could get either of those to idle at 800 or lower. I just wouldn't pick that much split with your goals and setup.
Making a cam idle low is pointless. You need to idle it where it wants to idle at. You can make it run at a very low RPM, but it is not right. If you want the car to run best, you have to give it a reasonable idle. A cam with both durations in the 220's may do well at 800, but the car will run smoother, create more manifold vacuum, and be quicker on response if you give it a more reasonable idle (maybe around 900, but this really depends on the cam/setup). 10-12º split is also pretty big, not sure why you would want that much exhaust duration.
Sounds like the cam you want is going to have minimal overlap.
Sounds like the cam you want is going to have minimal overlap.
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With a cam that small there is no reason for an idle that high. As long as the idle is low 50's KPA with a cam of that size it is enough. I agree that he should ask someone that does this for a living. Some of us work in this field. He wouldn't want to call a cam company, 5 calls will get you 5 different answers. If he were worried about the cam being right he could just go through Patrick G. It's very rare that people wouldn't agree with his cams and his customers always seem happy.
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Verdad Gallardo TECH Veteran
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Holy crap, why so much split on cathedral port heads? I assume you're spraying? Have an idle clip?
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Teching In
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Zippy, I have contacted some vendors, and you are correct, their opinons are all over the board. What worked for the LS1 and LS2, is different for the LS3, at least that is what I am told. Another issue is that none of the vendors want to discuss cam SPECS, so i refuse to buy a cam, without knowing the specs. They just tell me that cam XYX will work for me.
Zippy, I have contacted some vendors, and you are correct, their opinons are all over the board. What worked for the LS1 and LS2, is different for the LS3, at least that is what I am told. Another issue is that none of the vendors want to discuss cam SPECS, so i refuse to buy a cam, without knowing the specs. They just tell me that cam XYX will work for me.
Zippy, I have contacted some vendors, and you are correct, their opinons are all over the board. What worked for the LS1 and LS2, is different for the LS3, at least that is what I am told. Another issue is that none of the vendors want to discuss cam SPECS, so i refuse to buy a cam, without knowing the specs. They just tell me that cam XYX will work for me.
If you know enough about the specs to be able to tell if you want to go with a recomendation that is given to you, then why not spec it out yourself.
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Because I am by no means experienced in the field. I would not know the lift, LOSA, lobes, targeted static and dynamic compression ratio, etc...
All I am saying is that the guys that are really good at doing this rarely give the specs away.
Free advice is most often worth exactly what you pay for it.
Whichever road you choose, have fun and I hope it turns out well.
http://s48.photobucket.com/albums/f2...t=MVI_2103.flv
If It were me and this IS what I am going to do once I get to that point, I would call LG motorsports or Vengence racing. These two companies seem to have the most knowledge of what cams the LS3 heads like and they both are putting down higher numbers then anyone else out there. Vengence is going to be in this months issue of GM high tech magazine and Louis at LG motorsports has some very impressive numbers coming from his cam only LS3 engines. Both have made over 500rwhp on stock ci LS3's
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Yes sir, I will be spraying a 150 and Pat G. helped me pic this cam, awesome guy for anyone no sure which way to go. Here is an idle clip and it idles perfect at 750rpm through the stock mufflers.
http://s48.photobucket.com/albums/f2...t=MVI_2103.flv
http://s48.photobucket.com/albums/f2...t=MVI_2103.flv
As for the thing with Vengance or LG, either are great options. I'm not sure putting down the big number is more the concern, but the biggest number and keeping it as close to driving like stock as possible. Fortunatly he can run a smaller cam and make up the difference in power and airflow by changing intakes and running ported heads. Ported heads and a good intake will be a big increase in power and allow higher rpm with the smaller cam. Kinda the same way an LS7 pulls as high as it does with a small cam. Good flowing heads and intake can work wonders. Those with 1 7/8 headers will get him what he wants.
On the idle speed issue, here is an example of not needing a high idle. This is an L76 G8 with a 224/230 .581/.591 114LSA. Note the decent vacuum numbers at a reasonable and yet not high idle. Both in gear and in park are in the log. The fuel trims are still off a bit and it isn't perfect yet, but idles great driving around or sitting still.
Last edited by zippy; Feb 17, 2009 at 11:54 PM.