LQ4 build---low end torque
08-28-2015, 11:04 PM
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LQ4 build---low end torque
Hello all! I have a 2005 Suburban 2500 with a 6.0 and a 4L80E trans, 3.73 front and rear diff.
I don't know who can answer this, but any advice is greatly appreciated.
And the fun begins... I have ZERO aspirations to have a drag strip, high RPM truck. 50% of my driving is city (40 mph and less) 25% is highway, and 25% is towing (10K pounds or less)...I will list my current mods later, but basically, all i have are basic, bolt on upgrades...with a few tricks up my sleeve. I am looking for:
1)LOW END TORQUE...I have zero need/want for high RPM power. If my engine ever sees 5,500+ RPM, you can take a toe
2)RELIABILITY...This is my daily driver, and if anything, I want to increase reliability
To my knowledge, the best answer to my question is to increase displacement. I have found an all forged bottom end that will put me at 408CI. To me, this is the solution to both of my requests.
BUT!!! If i drop in a bad a bottom end, i naturally have to pull my engine. And I'll be damned if I wont change the cam and heads at the same time.
So, finally, my main question is...what heads and or cam should I install?? I've read about 243 and L92 heads, but those will mainly just improve peak power (again, this is to my knowledge)
http://www.hotrod.com/how-to/engine/...ylinder-heads/
^^^I wont get power until 5K RPM??? This is the exact opposite of what I want.
Again, thank you for any advice.
I don't know who can answer this, but any advice is greatly appreciated.
And the fun begins... I have ZERO aspirations to have a drag strip, high RPM truck. 50% of my driving is city (40 mph and less) 25% is highway, and 25% is towing (10K pounds or less)...I will list my current mods later, but basically, all i have are basic, bolt on upgrades...with a few tricks up my sleeve. I am looking for:
1)LOW END TORQUE...I have zero need/want for high RPM power. If my engine ever sees 5,500+ RPM, you can take a toe
2)RELIABILITY...This is my daily driver, and if anything, I want to increase reliability
To my knowledge, the best answer to my question is to increase displacement. I have found an all forged bottom end that will put me at 408CI. To me, this is the solution to both of my requests.
BUT!!! If i drop in a bad a bottom end, i naturally have to pull my engine. And I'll be damned if I wont change the cam and heads at the same time.
So, finally, my main question is...what heads and or cam should I install?? I've read about 243 and L92 heads, but those will mainly just improve peak power (again, this is to my knowledge)
http://www.hotrod.com/how-to/engine/...ylinder-heads/
^^^I wont get power until 5K RPM??? This is the exact opposite of what I want.
Again, thank you for any advice.
Last edited by zachman078; 08-28-2015 at 11:08 PM. Reason: Missed something
08-28-2015, 11:16 PM
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Noted...I convert vehicles to run on CNG for a living, and have an...intermediate level of engine tuning/building knowledge. And I am a HUGE fan of forced induction. To me, it just makes sense. I prefer turbos myself, mainly because it's "free power". I can (personally) install 2 small turbos and still get low end power, and of course top end. I have access to turbos that will spool around 2K RPM. I can fab the manifolds and everything, but I have so little programming knowledge, it spooks me. I know for a fact that i'll need to re-program my ECU, and that the cam profile will damn near dictate the performance of my turbos. (I am also learning cam profiles...I know the basics, but it's very complicated)
08-28-2015, 11:20 PM
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For what you're wanting, there would be no real reason to swap out the stock cam with FI.
And I would prefer the supercharger for all-out reliability. Just bolt on and go. With turbo, especially twins, there's a lot of re-routing of factory components and changes that could potentially reduce reliability not to increased heat in the engine bay.
And I would prefer the supercharger for all-out reliability. Just bolt on and go. With turbo, especially twins, there's a lot of re-routing of factory components and changes that could potentially reduce reliability not to increased heat in the engine bay.
08-28-2015, 11:36 PM
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That will definitely save me time and money. And with my engine having the long intake runners and it's current cam profile, I like it's torque curve as is. So great news that I could run my stock cam. How about the heads?
And you make a very valid point regarding the ease of installation. I agree 100% that a bolt on SC would be very easy. But I have access to many turbos (my shop has hundreds that came off of small I4 diesels..I can get the specs tm if that helps)I am very good at fabricating manifolds and tubing for intercoolers, oil lines and all of that. The reason I'm sh** at the rest is that we employ an engineer from Italy that does basically everything electrical in our shop, and I piggyback off him. So for $$ reasons, if I were to go forced induction, I would definitely go turbo.
That being said, I don't know if my ECM, re-programmed or not, will even support a turbo set up.
And you make a very valid point regarding the ease of installation. I agree 100% that a bolt on SC would be very easy. But I have access to many turbos (my shop has hundreds that came off of small I4 diesels..I can get the specs tm if that helps)I am very good at fabricating manifolds and tubing for intercoolers, oil lines and all of that. The reason I'm sh** at the rest is that we employ an engineer from Italy that does basically everything electrical in our shop, and I piggyback off him. So for $$ reasons, if I were to go forced induction, I would definitely go turbo.
That being said, I don't know if my ECM, re-programmed or not, will even support a turbo set up.
08-29-2015, 10:46 AM
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Go with the twins! If you can fab it it will do well. You will need slightly bigger injectors, a 2 BAR map sensor, and better fuel pump. Programming the PCM requires a lot of reading but its possible. I never finished high school and built and am tunning my own turbocharged truck. If you have a bit of money buy a holley denominator setup and tuning it is a breeze. They are around 3K though. Otherwise take it to a local tuner. Good tune will cost around $500.
