5.3 Performance

[Avalancher]

I have an '02 Avalanche with:

Hypertech Reprogrammer

FIPK2

Gibson Catback

Granatelli MAF

 

Flex-a-lite fan on order to remove stock fan.

160 thermostat on order

 

There is a significant HP gain over stock.  BUT, I still have no "off the line" power.  I know this is a heavy vehicle, but I now have gobs of HP (stock 285 + mods = 3??).  In my efforts to get off the line more quickly, I have held down the brakes and pressed on the gas to torque it up.  I've noticed that even if I floor it with the brakes on, it will only rev to about 1800 rpm's.  Again, let off the brakes, no go power off the line.

 

Any ideas on what the problem is or how to get around it?  Is anyone aware of a torque limiter or rpm limiter somewhere in the system that would prevent me from being able to chirp the tires?  

 

Any other suggestions of performance mods I can make to the vehicle?

 

Thx,

MB-)

[Dihappy]

Hey bro,

Welcome!!

 

Remember that the rated HP and Torque is only at the flywheel and not at the rear wheels.

 

Im sure Gandolph will chime in with his supercharged Avy soon

[jst4f]

Hey bro,

Welcome!!

 

Remember that the rated HP and Torque is only at the flywheel and not at the rear wheels.

 

Im sure Gandolph will chime in with his supercharged Avy soon

??? Dihappy,

 

Are you sure that the rated HP and torque are at the flywheel.  I had always been told that it is at the wheel whichi is why the values can change with the tire size, just like the speedometer.  Larger tires reduces the HP/torque and make the speedometer read lower than actual speed.  I was not aware that the dynamoters (sp) were hooked up to the flywheel and not the rear tires.

 

I do know that the AV has a RPM limiter (~5600 rpm).  It is mentioned in the owners manual but nothing at low rpm.  I have never tried to chirp the tires so I can say if my AV is rpm limited in idle.   I wonder if the drive by wire throttle has a response time to it.  It simply can't respond to the rapid petal to the metal jack rabbit start like a direct connect throttle can.  Just a guess. ???

[MarkD]

Manufacturers give engine hp and tq ratings at the flywheel.  This I KNOW!  Different transmissions dissipate different amounts of power.  Auto tranny's usually take about 20%, Manuals use about 15%.  This can vary widely, I have seen a T-56 Camaro lose 11% to the tranny (engine dyno vs. chassis dyno).  I have also heard that the Allison tranny takes 25%-30% (haven't seen).  Larger tires/wheels effect hp and tq due to increased rotational mass/inertia.

 

The torque converter has more to do with "Power-braking" than any electronics do.  If you want more off the line performance, look into a different torque converter, shift kit or lower (higher numerically) gear ratio (or all of the above).  

 

Drive-by-wire would be more responsive to throttle input than a cable.  They are puting it into the Vette.

[Avalancher]

There is an RPM limiter at around 5600, the HPP3 lets you change that (not that I want to), I just want to realize my power at takeoff.

 

I'm thinking there's a rev-limiter that kicks in under certain circumstances (maybe trans pressure, maybe to zero wheel motion,...?), drive by wire may be the method the computer uses to restrict rpm's when the limiting condition exists.

 

I remember previous vehicles that would torque up to the point that the engine would start to bog down when you would hold the brake and press the gas pedal down.  This thing torques up just a little then holds.

 

I sure want to figure out how to get around this...

 

Any ideas?

MB-)

[MarkD]

I remember previous vehicles that would torque up to the point that the engine would start to bog down when you would hold the brake and press the gas pedal down.  This thing torques up just a little then holds.

 

This is controlled by the "stall" of your torque converter, not a rev limiter.  If you want to change the "stall" you can either change your torque converter, or drastically increase(100+) your tq output.

[Dihappy]

If Im correct, there is "Torque Management" on our engines.

 

It sucks, but i heard you could cheat and rev the engine right quick before you stomp on the pedal to overcome it.

[SilveradoWV]

When I had my ZR2 Blazer, I was active in some s-series boards. We never got near the estimated HP gains that were stated by the performance manufacturers. Like we only got about 3 HP out of a drop in K&N and about 7-9 out of the FIPK. The only thing that I have heard that gives an accurate HP gain is the Electronic Supercharger and it gives 15-20! SO what I am getting at is that all your mods might not be adding up to the HP you think!

[gandolphxx]

I have an '02 Avalanche with:

Hypertech Reprogrammer

FIPK2

Gibson Catback

Granatelli MAF

 

Flex-a-lite fan on order to remove stock fan.

160 thermostat on order

 

There is a significant HP gain over stock.  BUT, I still have no "off the line" power.  I know this is a heavy vehicle, but I now have gobs of HP (stock 285 + mods = 3??).  In my efforts to get off the line more quickly, I have held down the brakes and pressed on the gas to torque it up.  I've noticed that even if I floor it with the brakes on, it will only rev to about 1800 rpm's.  Again, let off the brakes, no go power off the line.

 

Any ideas on what the problem is or how to get around it?  Is anyone aware of a torque limiter or rpm limiter somewhere in the system that would prevent me from being able to chirp the tires?  

 

Any other suggestions of performance mods I can make to the vehicle?

 

Thx,

MB-)

Hi there, welcome to the board and "High Performance" - we do all things here, even Avalanches [i have one] - some thoughts:

 

1. Getting off the line - interesting concept, not without a some additional work:

 

"To race, you pull up to the starting line, put the shifter back in First gear, hold down the Trans Brake button and again put it to the wood. The engine revs up, and the world vibrates like you're on a coin-operated bed in a cheap motel, but the Trans Brake keeps the car still. The fun begins when the amber lights on the starting line's Christmas tree flash, and you let go of the button."

 

You don't want one of those, too much work. But, maybe a Launch Control/Line Locker

 

OK, so much for fun - what can you do with that beast.

 

1. Take the bottom plate out from under the K&N, let the front fender well act as an inlet. Put a mesh screen in if your worried about water, or get the K&N sock.

 

2. Put the stock [screened] MAF back on unless you have an ATAP that you can check for lean conditions with the Granatelli.

 

3. Consider some decent mid to long headers - JBA, TOG, or ASM [Hamm if you are willing to wait].

 

4. The Gibson is helping you at the top end, hurting at the low end, loss of torque, you need to balance the pressure for normal driving - frankly you would be as well advised to get electrically controlled cutouts and keep the stock muffler.

 

5. Consider a supercharger if you want to wake that 5.3L up, with intercooler [unless you live in Alaska] - my favorte Whipple, also Magnacharger - the centrifugals are OK also, just not ideal for launching a 3 ton truck.

 

6. Of course there is nitrous and water injection - quick 100.

 

7. Now lets consider the drivetrain, you have the 4L60E, sturdy, proven and respectable, but a little weak. I would slip in a Yank [or equivalent] 2600, replace the backplate that is notoriously weak and add Kevlar clutches. Keep in mind that your losing 25+% between FWHP and RWHP.

 

8. Install the Transgo kit in the tranny, no truck should be without it - makes them shift like a Vette in heat - will help it live through the abuse.

 

9. Install a Direct-Hits ignition system or high capacitance racing wires and NGK plugs.

 

10. If you do most of the above, you will still hit a brick wall, courtesy of GM, called Torque Management. HPP3 can not fix this, only re-programming the PCM can - costs about $500, just a little more than the HPP3 [sell it on Ebay].

 

11. Cancel the extended Warranty and get your money back to help pay for all of this. Might want to invest in better tires, BFG AT/KO, of Pirelli Zero's, neither spin, they just go!!!

 

12. Go to the track and smoke a 'Tang or two.

 

Hope this helps, feel free to ask if you think I missed anything, or you want to disagree, if I had all the answers I wouldn't be here, still trying to learn myself.

 

 

 

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[Dihappy]

Sweet Jack!!

 

Do you have the Transgo kit??

 

What does it consist of and how much is it?

 

What tranny's does it work with?

[gandolphxx]

Sweet Jack!!

 

Do you have the Transgo kit??

 

What does it consist of and how much is it?

 

What tranny's does it work with?

The transgo re-program kit has been installed and broken in - wow, this baby shifts like a stick Vette now - 1st to 2nd will scare your g/f or boss. The shifts are like "right now!".

It drives smoother, quicker and faster. I am impressed and delighted, cost less than I expected and exceeds my expectations.

 

Should work with any 700 variant, certainly the 4l60E, just keep in mind that this is a medium grade tranny, might want to have it beefed up per my comments above.

 

Here is a good reference Improving the 4L60E

[Avalancher]

Thanks Gandolphxx, I don't think I'm ready to put a supercharger in just yet, I'll wait until the factory warranty runds out.  Or at least a little closer.

 

<7. Now lets consider the drivetrain, you have the 4L60E, sturdy, proven and respectable, but a little weak. I would slip in a Yank [or equivalent] 2600, replace the backplate that is notoriously weak and add Kevlar clutches. Keep in mind that your losing 25+% between FWHP and RWHP.>

 

You're talking torque converter here right?  Can you explain what "stall" refers to here?

 

<8. Install the Transgo kit in the tranny, no truck should be without it - makes them shift like a Vette in heat - will help it live through the abuse.>

 

Is this a shift kit or electronics?

 

<9. Install a Direct-Hits ignition system or high capacitance racing wires and NGK plugs.>

 

Do you really think this makes any real difference?

 

<10. If you do most of the above, you will still hit a brick wall, courtesy of GM, called Torque Management. HPP3 can not fix this, only re-programming the PCM can - costs about $500, just a little more than the HPP3 [sell it on Ebay].

>

 

Bummer here, I like all of the goodies I can modify w/ the HPP3, I plan on changing tire sizes & maybe diff's.

Have you heard of a place called fastchip?  They are about 300 miles from me and do these kind of reprograms.

 

Thx,

MB-)