Performance upgrades without a blower

[Fast55]

I'm interested to know if there's much to be gained out of these Gen IV trucks without going to forced induction. My truck is a 2009 Tahoe 4X4 with the 6.2. I've already had the POS transmission replaced once under warranty and I do have a good relationship with my dealer, but they gag at the thought of another 100-150 HP through the stock drivetrain and honestly, I'm a little leary of the required tuning. I bought a flashscan a little over a year ago and went through a LOT of different BB tunes. I've never been 100% satisfied with the results, but it does run better than stock. I have a K&N in the stock air box with Airraid tube. From my seat of the pants dyno I'd say I picked up at least 30HP and it walks a stock Esky easily, but I want more. I've considered headers, but I don't want the noise. What could I get from a cam? Head work? What is the difference between these truck 6.2's and what's in a Camaro? Is 450 HP possible on pump ( Ca. 91 ) gas?

 

[MJEngineering]

Your experience is not uncommon and like you have discovered the newer engines are pretty well managed from the factory. The trucks are very heavy and so even adding 100 horse isn't really even enough to satisfy most people looking for more power.

You can go with a huge cam but then you will have other sacrifices, same goes for high compression heads or a stroked engine. Again, the factory squeezed about as much from the hard parts as possible. Cams and heads are really for dedicated light weight racing vehicles and after building MANY engines and vehicles I feel confident in that opinion.

There are minimal differences in these engines across the entire LS family, the vehicle's weight being the major factor in how fast they usually are. Unfortunately the SUVs are at the upper end of that spectrum and require quite a lot of power to get to move.

My advice to all new vehicle owners is to boost your stock engine, keep all your factory reliability and driveability as it is now but when you hit the gas the truck will actually get out of its own way. Install is quick and minimally invasive and few parts are removed, reducing installer potential error and callbacks.

I have built many head/cam trucks but the ones that really benefit are short cab short bed sport trucks. SUVs need boost and after you drive one with it you will never want to go back. There is nothing short of a LOT more displacement that will get you acceleration/power/performance like that.

Basically it boils down to spending thousands in hard parts and thousands more in labor chasing down a few horsepower here and there with a lot of effort OR a few thousand on a blower and a few hundred installed and you've added 50% more power pretty much everywhere. There are a few people building upgraded 6 speeds as well, definitely something to consider even on a stock engine if you will drive it hard. A nice custom torque converter is also suggested and even if you kept the entire truck stock a converter will still really help your launch.

Remember once you have converted to a boosted setup your power ceiling is virtually unlimited. You can then actually maximize each link of your driveline and as you upgrade parts you can easily increase the power.

I hope this information helps even if it isn't what you were hoping to hear. As always feel free to call at any time. 508.320.6807

MJE

 

[Fast55]

I figured as much, but again, I'm looking for 450-465 HP, not 550 HP. I really don't think the drivetrain is up to that unless I start looking at transmission and/or rear axle work and if I have the power, it'll get used. I have had several different forced induction vehicles and do like the power, it's usually tuning that makes or breaks it. What are the weak points in the trans? Any idea of cost to upgrade it? I take it you have extensive experience with tuning boosted 6.2's? Can you work with Flashscan logs?

 

[MJEngineering]

You can have the power but the drivetrain only really suffers when you put all that power down while getting traction. If you keep your foot out of it you can get remarkable durability from stock parts. 450 horse is only a minor bump (30 horse) from the power you have now. Also remember that measurement is taken at about 6000 rpm so if you add 50 there then there will be a lot less power where you actually drive (2-4000).

Tuning is critical to getting boosted engines right but you do have a computer that is capable of properly supporting a boosted vehicle as a side effect of GM now offering supercharged LS engines.

I rebuild manual transmissions but always send out the automatics. Haven't seen too many 6 speeds fail yet but the weak points are usually the clutches and sun shell, followed by input and output shafts. (AFAIK)

We have swapped 6.2 blocks into lots of vehicles and built one that produced 1,400 horse with twin turbos. Tuning is the same for any boosted engine.

Do you mean EFILIVE flashscan v1? Never tried feel free to email me one. Should be fine if it is *.EFI.

MJE

 

[Fast55]

Mine is a Flashscan V2, the files are *.TUN.

 

[MJEngineering]

If you have EFI LIVE already you will be able to tune that truck with some good advice and free time. Feel free to msg me I can look at your tune and point you in the right direction gladly. Don't forget ls1tech and efilive forums are great starting points.

Keep in touch,

MJE

 

[John Root]

I have a 2014 Chevy Tahoe LTZ I have 213.000 Miles in it and still continuing I use synthetic oil Mobil and engine additive and K&N filter and I change it every the oil each 50%.