2005 Tahoe LS Swap sluggish off line

I am admittedly a novice when it comes to tuning. I started a 2005 Tahoe 4wd project in 2023 and it has 290k miles. It was owned by a GM technician and kept in immaculate mechanical condition, but had some hail damage. I wanted a secondary vehicle to build as a sleeper.

Here is what I went with:

5,3 LM7
24 tooth reluctor wheel
Carillo H-Beam rods
10.5 compression Vertex pistons with moly rings
Balanced and blueprinted
243 heads 2.00 intake 1.55 exhaust valves
Roller rockers 1.7 ratio with C-clip upgrades
Cam duration .050 Lift.545 LSA .112
Trailblazer SS intake
90 MM DBW throttle body
Stock Manifolds
Borla dual exhaust
50 lb injectors


Transmission is a 4L60E
2800 Stall
Corvette Stall 5 pinion planetary
Stage 2 shift kit
Heavy duty clutches

3:08 rear end/front axle gears with G80

I have no traction control or ABS but do have the dreaded hydroboost brakes/power steering

I am rolling on 265/70R17 tires.
Here is my issue. This thing is very sluggish off the line. It rips once the rpms build but won't even chirp the tires off the line. It has the dreaded 2000 rpm rev limit when power braking.

I have turned off everything in transmission and engine that I know to turn off.

Being new to this site, and also not really knowing how to actually log, is it possible for me to send my tune so someone can see if I have something missing?

This is a daily small town run around driver, so I know there is more in it, but everything I did was on the side of caution.

I have read this may be a non fixable issue, but wanted to rule out my tune. I have learned so much from this site and the people on it, but some of this is way over my head.

Thank you for any help that you can provide.

You left out the cam duration in your description. The part number and brand of the fuel injectors will also be needed info. A little bit of reading should be enough for you to figure out how to log data, and you can post your tune and data log directly to the forum. Of course, it is still a heavy truck with 3.08 gears, so there is only so much you will be able to do to get a 5.3 to accelerate well off the line.

It will always be a DOG off the line. I had a RCSB 5.3 truck at one point. With the stock camshaft it ran best with a Yank 3,600 rpm converter, 4.30 gear and 28" tall drag radials. It was a DOG with the stock 3.42s and stock converter. I had a Hemi Ram that was a nearly 17 second dog as it was built with the factory 20s and 3.55 gears. It ran well with a 3,400 converter and 4.56s. Later put a 265/265 @ 0.006, 212/212@ 0.050, 0.540" lift, 114+4 Comp custom grind in it.

I just tuned a 2003 Avalanche with a Torque Storm at 12 psi on it. It has the stock converter, stock 3.73s and GM 22s with P305/40R22s on it and it is still a dog until it is up to ~4,000 rpm.

Quote:

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Originally Posted by gametech

You left out the cam duration in your description. The part number and brand of the fuel injectors will also be needed info. A little bit of reading should be enough for you to figure out how to log data, and you can post your tune and data log directly to the forum. Of course, it is still a heavy truck with 3.08 gears, so there is only so much you will be able to do to get a 5.3 to accelerate well off the line.

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Duration is .050 Intake 222 Exhaust is 231

Not sure of PN's but here is what I ordered as a kit from Glens https://www.glennsautoperformance.co...ails-injectors

It is not letting my copy and paste my tune for some reason. I am out of state for the next 2 weeks so I will have to figure it out when I get back.


Thank you for your help!

Quote:

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Originally Posted by Husker525

2800 stall and 3:08 rear end/front axle gears
.

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will always be a dog with that
2800 is like 600 over stock and 308s are for shooting not racing..

Quote:

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Originally Posted by bk2life

will always be a dog with that
2800 is like 600 over stock and 308s are for shooting not racing..

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That may be where I end up. And FWIW, you hit me right in the wheelhouse with the .308 reference. My side hobby is PRS/ELR LOL

Yea thats not a good combination of parts.
The 3.08 gears, Tire size, Cam, Converter doesnt play well.

Get the tune and a datalog posted when you get back. There are some things you can try.
But the heavy tahoe has some decent suspension so they arent going to spin that easy. You could add about twice the power and it still wouldnt spin if your brakes are decent as well.

Changing the cam would be step one. Even with ideal gearing that cam isn't the best choice for a truck.

A cam will always be a compromise. High end for low end.. etc.. this type of cam is moving things into the high end that you don't see too often in your heavier vehicle especially with the tire/gear combo you have.

All great information! I noticed this was a higher rpm loving engine, within reason. I had the limiter set at 5000 rpms to be on the safe side. I bumped up everything up to 6000 and it really seems to like it. I can neither confirm nor deny that the top speed on this is way faster than I care to go for too long with this style and weight of the vehicle and the tires. She floated and was still pulling at speeds my crotch rocket hits. (Hypothetically speaking of course).

I might just save on tires and keep it as is. It is very reliable. I appreciate all the input. I also thought of disengaging the transfer case and changing out the rear end gears. I do use it occasionally when we get blizzards, but no traction control or ABS make it interesting to drive. I have other 4wd vehicles I could use too.

Going to a 4.10 gear and a smaller cam would wake it up very nice.
That cam in a 5.3 should still be making some power around 6500rpms.

To give rough idea.. 3rd gear with TCC locked you would be going roughly 183mph at 6000 rpms.
Looks like 2-3 upshift at 6500rpms would be 122mph....

:bigshock::bigshock::bigshock::bigshock:^^^^^^^^

Quote:

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Originally Posted by RDF1

Going to a 4.10 gear and a smaller cam would wake it up very nice.
That cam in a 5.3 should still be making some power around 6500rpms.

To give rough idea.. 3rd gear with TCC locked you would be going roughly 183mph at 6000 rpms.
Looks like 2-3 upshift at 6500rpms would be 122mph....

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I had to check the math but looks like you're right.

Quote:

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Originally Posted by edcmat-l1

I had to check the math but looks like you're right.

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Slightly high geared..
Attachment 162853

last year i had a guy bring me a old car with 2.56 gears and 6.0/4L60 on 28's with rubber band 30" tires... Talk about fun. 4th gear was usless.

Quote:

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Originally Posted by RDF1

Slightly high geared..
Attachment 162853

last year i had a guy bring me a old car with 2.56 gears and 6.0/4L60 on 28's with rubber band 30" tires... Talk about fun. 4th gear was usless.

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Lol, 1st and 2nd remind me of my Express with a 4L85E and 3.73s.