lq4 cam questions
03-29-2014, 02:11 PM
#1
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lq4 cam questions recently aquired 03 silverado lq4 and im wanting to cam it. does anyone know if i have to get reliefs cut in the pistons to run the ***** Thumpr 283THR7? 109 lsa, 283 intake duration, .563 lift, 303 exhaust duration, .546 lift. i looked but didnt find any threads that answered my specific question.
03-29-2014, 05:15 PM
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You would probably make more power with a smaller cam, pretty sure those numbers aren't at .050. If the truck is stock you would need a higher stall, or lower gears or both to get any gains for that cam other than sound. You can always lower your idle a bit or pull timing at idle in the tune to make it lope more.
03-30-2014, 12:24 PM
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This truck isn't really gonna be a "daily driver" it's gonna be more like a mud toy so there are other mods planned including forced induction. I just wanted to know if I could run stock compression ratio with this cam. But I'm open to suggestions for cams that will give me better power
03-30-2014, 12:45 PM
#5
You can most certainly run stock CR with an aftermarket cam. Making sure the new cam fits well into the application's intended usage is most important.
I have a 215/215 .604/.604 112lsa cam that runs very well in the trucks it's been installed into.
I also have a 219/219 .609/.609 112lsa cam that runs very well also, but will require a small stall converter. You could push it and run it with a stock stall if you wanted to, but I'd recommend a 2800 stall.
I also try to discourage customers from purchasing a "one size fits all cam" that they're told will work great with boost later and run great N/A now. IMO there is no optimal in between. Any cam will work in any application, but it's how optimal it is will determine the final product.
Most used cams sell for 250-275 dollars. If a new cam is 380-400, you can recoop a large amount of your dollar spent and put it towards the correct camshaft when the time comes.
I have a 215/215 .604/.604 112lsa cam that runs very well in the trucks it's been installed into.
I also have a 219/219 .609/.609 112lsa cam that runs very well also, but will require a small stall converter. You could push it and run it with a stock stall if you wanted to, but I'd recommend a 2800 stall.
I also try to discourage customers from purchasing a "one size fits all cam" that they're told will work great with boost later and run great N/A now. IMO there is no optimal in between. Any cam will work in any application, but it's how optimal it is will determine the final product.
Most used cams sell for 250-275 dollars. If a new cam is 380-400, you can recoop a large amount of your dollar spent and put it towards the correct camshaft when the time comes.
03-30-2014, 12:55 PM
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Ok so I'm gonna be running 12psi on the stock 9:4:1 cr. with most of this trucks use being off road and pretty consistently above 3k rpm. Got any recommendations aside from the two you already mentioned?
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03-31-2014, 09:45 AM
#11
With such a small turbo here is what I would recommend:
214/214 .595/.595 114+4
If the cam is too large with a small turbo, the airflow demand of the engine (VE%) becomes greater than what the turbo can efficiently supply at a given pressure. Keeping the compressor wheel as efficient as long as possible will provide a higher average power number across the board.
That said, there is only so much you can do with a given displacement with a given compressor wheel. I would shift your engine around 5600-5800rpm as that will be about the limit IMO of what that turbo can efficiently supply in terms of airflow up to that engine speed.
The cam could be made even smaller to attempt to increase the operating range. This may sound backwards from what is normally done in N/A engines, but this isn't a N/A engine.
If you wanted to try and extend usable power as far as possible I would suggest this camshaft:
210/214 .556/.559 115+3
IMO this cam will lose peak torque over the first cam I mentioned, but it will decrease airflow demand at a higher RPM(decrease in VE) which should allow the compressor to stay efficient a bit longer. Helping carry power further. It being a mud truck though, I'd go for as much torque as I could get.
214/214 .595/.595 114+4
If the cam is too large with a small turbo, the airflow demand of the engine (VE%) becomes greater than what the turbo can efficiently supply at a given pressure. Keeping the compressor wheel as efficient as long as possible will provide a higher average power number across the board.
That said, there is only so much you can do with a given displacement with a given compressor wheel. I would shift your engine around 5600-5800rpm as that will be about the limit IMO of what that turbo can efficiently supply in terms of airflow up to that engine speed.
The cam could be made even smaller to attempt to increase the operating range. This may sound backwards from what is normally done in N/A engines, but this isn't a N/A engine.
If you wanted to try and extend usable power as far as possible I would suggest this camshaft:
210/214 .556/.559 115+3
IMO this cam will lose peak torque over the first cam I mentioned, but it will decrease airflow demand at a higher RPM(decrease in VE) which should allow the compressor to stay efficient a bit longer. Helping carry power further. It being a mud truck though, I'd go for as much torque as I could get.
Last edited by Sales@Tick; 03-31-2014 at 09:52 AM.
03-31-2014, 12:04 PM
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i think one of the first two would be best as i dont want to sacrifice torque. and the turbo is gonna get bigger in a yr or less anyway.
