Upgrades?????

[shlprk]

Hey guys,
I'm in the process of doing alot of research on the hummer3 for a future buy.
My question is for you experts.
1.Exhaust- yes or no and who makes the best?
2.Air intakes- yes or no who makes the best?
3.ECM-yes or no and i think raptorq is the only one.

So guys before you reply let me tell you what i'm thinking.
I dont want a 8 cyl too much gas. looking for a toad for my rv, and this will be used as my daily driver. I still want something with reasonable power. This is why Im looking for upgrades.
I have my eye on an 06, thinking about putting 35's on it. I know this set up will require a lift, what do you recomend?
1. Rancho 4" lift (smooth ride)?
2. Cranking up keys (very stiff ride)?

So if you can help with any comments I would appreciate it. Thanks in advance

[Field Scout]

Originally Posted by shlprk

Hey guys,
I'm in the process of doing alot of research on the hummer3 for a future buy.
My question is for you experts.
1.Exhaust- yes or no and who makes the best?
2.Air intakes- yes or no who makes the best?
3.ECM-yes or no and i think raptorq is the only one.

So guys before you reply let me tell you what i'm thinking.
I dont want a 8 cyl too much gas. looking for a toad for my rv, and this will be used as my daily driver. I still want something with reasonable power. This is why Im looking for upgrades.
I have my eye on an 06, thinking about putting 35's on it. I know this set up will require a lift, what do you recomend?
1. Rancho 4" lift (smooth ride)?
2. Cranking up keys (very stiff ride)?

So if you can help with any comments I would appreciate it. Thanks in advance

Someone will say it so I guess I'll be first "search" is your friend.
However; I'll do my best to help,
1-exhuast, dont know myself but understand Borla is a good set up(not too noisy)
2-intake, not if you offroad, also basicly a waste anyway no real improvement
3- ecm, did mine w/pcmforless, maybe 1/2mpg better only real difference I noticed was the change in shift firmness the added
As for 35's no lift needed alot on the forum turned thier t-bars(did mine 5 turns to compensate for the extra weight from my winch)ride is about the same as long as you dont go crazy
also according to the discount tire web page calculating speed chande w/tire size changes 33 to 35 is approx 3mph different so your mpg may look worse but my 33's are 3mph slow according to my cop buddies radar.also no way to ajust speedo at this time
keep things off your roof ie. roof racks and your mpg will be ok with my rack on I get 15 to 15.5mpg, off I get about 17mpg
good luck and if you buy get the adv pkg good extras for not that much more

[shlprk]

Field scout Thank you for the 411, Ive done the search and I'd thought if i ask they will deliver. if i ask all that i need in one post it will save me and those from all that typing.
So I can run 35's stock,? I want a level look, but I dont want a stiff ride. I have a 2500hd and I did the 3" key lift and it was really stiff. will this be the same ride as u have on your rig?
I really dont intend on putting anyting on the roof so i'm ok with that. but if your saying you get about 17mpg then i'l be ahead.
Do you happen to have a web site for pcmforless?

Thanks again for your help

[Field Scout]

When I say 35's actually its 315/75/16=34.5? inches not true 35x?x16 you will get some rubbing at full lock but back off the steering wheel about an inch and youll be fine
on leveling the H3 I turned my torsion bars 5 turns to get it close to level, less stink bug look but not full level have heard people that went full level got a bouncy ride, finally I think its pcmforless.com if you go through them the way to go is let them send you a loaner, when you get it send them yours to reprogram and send back. this will save you from having to do a CASE relearn
Good luck

[HBH3]

I have 35's (yes 315's) on stock weheels. They only rub a tad against the sways bar on full lock on right turn, not left. That is easily fixable by welsding a small piece of metal on the turn stop.

I also have done the PCM for less and it made a noticeable difference; and I have a 5 spd not auto. They also do correct the speedo for larger tires so the mileage and speed are accurate.

As far as leveling, I did the Readylift leveling kit. The ride is the same, and it looks perfectly level.

Enjoy!

[shlprk]

Hey guys Thanks again, So you guys are not running any aftermarket intakes? I was just on the web sites and they all say that there products will increase hp and gas milage. this was off the dyno. anyone try doing intake and exhaust and ecm? just wondering.
Thanks for the suggestions I will look at readylift and check them out.
One question for you guys, to go with aftermarket wheels what offset is suggested, I say one demension cant find it again. And if i did a different offset will this increase or decrease the rubbing.?
Thanks again.

[RubHer Yellow Ducky]

The Spacer is really questionable on any vehicle.

Cold Air Intake ... Trace out your H-3, it already comes from the factory with cold air intake (send me your money instead)

Exhaust --- there you can gain a few extra horses...

[raptorman53]

For the money I think the re-program is the best. I have both the itake and exhaust. Between the two there is a slight inprove in both power and fuel mileage. I do like how the exhaust sounds though, so not a complete disappointment.

[Sewie]

Originally Posted by shlprk

One question for you guys, to go with aftermarket wheels what offset is suggested

Depends on the width of the wheel. Stock wheels are 7.5" wide and have 5" backspace. For a 8" wide wheel, you'll probaly want 4.5" backspace. The wider you go, the more backspacing you want.

[shlprk]

Thanks again guys, these ques may seem a little premature for me but like I said I'm trying to get all my research before I purchase this h3. Ive got my credit union selling my truck this weekend so hopefully things will work out.
So I guess the ecu/pcm4less and an exhaust r the way 2 go. Thanks 4 the 411 guys. I think I would like more hp's from the exhaust rather than the noise, so what do you recommend, i've been to volant, corsa, magnaflow, and borla. Which is the better in your opinions.??
Thanks in advance I think this forum is great, despite the posers that will invaid and try 2 put there 2 cents. keep it up guys

[Wisha Haddan H3]

For HP and torque gains, go with Gibson (not on your list) or Borla. Get the full catback, not just the muffler.

And just my 2 cents, but for any so-called performance products, do not expect better gas mileage. The only way to improve the mpg is to improve combustion efficiency or reduce parasitic losses (friction, air resistance), and airflow products do neither.

Air intake and exhaust mods may allow the engine to breathe better, but that only allows the PCM to add more fuel to accommodate the extra airflow. And it only happens when you ask for it (by pushing the throttle). Since the extra power comes from the extra fuel per engine revolution, you won't see mpg gains.

I highlighted "may" because there are other problems. The question isn't, "Do intake and exhaust mods eliminate restrictions?" You should be asking ...

1.) "Is the stock intake and exhaust more restrictive than the ports and valving in the engine itself?" You won't see any gains unless the answer is yes.

2.) "Did the company engineer the airflow specifically for my vehicle, with regard to the pulse frequency of air traveling through the pipes they designed?" Timing these pulses is critical to pushing air into the intake manifold (or extracting from the exhaust manifold) at the right time.

3.) "Does the aftermarket intake seal off hot engine air?" Hot air is less dense than cold air. In a given volume (like the combustion chamber), cold air will contain more oxygen molecules than hot air. Less oxygen is detected by the MAF, which tells the PCM to send less fuel to each cylinder, resulting in less power from each combustion cycle.

A lot of aftermarked intakes and exhausts actually reduce performance because the company (or kid with the pipe cutter), didn't design the system to your engine application, with these points in mind.

[Field Scout]

very nicely put

[shlprk]

Thanks, So Hadden are u suggesting that the only upgrade out there for this particular vehicle is the catback system? ( I would only put the catback on my vehicle, only way to go) I've read so many posts that they can c improve ments with the pcm4less upgrade. I was under the assumption that with the ecm upgrade that it would do all that, to improve shift points, mpg, and torque. You obviously know what your talking about, so is the pcm4less false with there advertisment and a waste of time?
Well if you cangive me more 411 I would appreciate it Thanks in advance.

[Wisha Haddan H3]

I honestly don't have any experience with PCM upgrades, but here's why I'm skeptical. Anyone who's actually chipped their H3, feel free to correct me.

Why people chip:

1. To move the powerband into a specific RPM range.

On engines with fixed valve timing, the timing doesn't change from low to high RPMs. The engineers had to decide not only where to optimize the powerband but also how to make the rest of the powerband acceptable while balancing power and fuel economy.

Aftermarket PCMs eliminate the power/economy trade-off and optimize timing in a specific RPM range (usually high-end for racing or low-end for towing and off-road). The trade-offs are poor performance in the off-range and engine stress from a combination of power in the optimized range and neglect in the rest of the band. Some companies offer an in-cab controller so you can pick your powerband for racing, towing, cruising or whatever.

2. To change the shift points (automatic trans)

This changes the RPM where each gear shifts up or down ... the same concept as the Power/Economy button on some cars. For maximum economy, you shift sooner to keep the average RPMs as low as possible. For maximum power, you stay in each gear as long as possible to stay in the powerband. Plus, when you shift, you're right below the power band and ready to accelerate through it.

3. To firm up the shifting (automatic trans)

This completes each shift faster. The thinking is that the faster you get into the next gear, the quicker you can get to the powerband in the new ratio. But it isn't as smooth between shifts and puts more stress on the drivetrain.

4. Correct the speedometer

If you change your tire size, you can usually correct it by chipping.

Why I wouldn't chip (even if I had an automatic):

1. The I-5 has VVT (variable valve timing)

VVT dynamically changes valve timing across the RPM band. Since GM didn't have to sacrifice power or durability at particular RPMs, they could optimize it from top to bottom. This partly explains the I-5's flat torque curve, providing almost as much torque at 2800 as it does at 5600 RPM. Basically, the RPM optimization is already done. There might be some wiggle room to trade economy for power, but you would really have to know what you're doing for minimal gains imo.

2. If you're driving hard, you're already flooring the pedal

... which keeps the transmission in gear through the power band for free.

3. Firmer shifts? Cool, you saved 0.5 seconds

4. Ok I admit it ... correcting for 35" tires would be cool.

5. Why risk voiding a 100,000 mile warranty?

6. Gas is expensive. It costs too much to lose a lot of fuel economy for marginal power gain.

7. Seat of the pants dyno? Come on ... The few people on this board who have tried chipping or programming the PCM said they "felt" a difference, but provided no convincing evidence. Give me dyno results, track times, and mpg measurements.

8. Time in the shop. I know a guy who chipped his truck. He won't shut up about the power gains, but it's always in the shop with engine and tranny problems. But then again it is a Dodge ...

So yeah, I'm skeptical, but I'd like to be wrong here. I want more power same as everyone else.

[ChevyHighPerformance]

I'll add my 2 cents.

The PCMs aren't chipped they are flashed through the diagnostic connector.

1) There are two areas to improve power: fuel and timing.

Timing - The PCM uses two 2D tables of data for timing - a high octane table and a low octane table. The tables provide the timing based on RPM and cylinder airmass (g/cyl). You can add timing where ever you want/feel. Optiminal timing improves both power and fuel utilization (fuel economy). These tables are optimized based on the octane fuel you want to use.

Fuel - There is a part throttle A/F ratio set at 14.7:1 to minimize emissions and improve fuel ecomony. During WOT (wide open throttle) there is another table that essentially provides the A/F ratio as a function of RPM. At high RPMs the stock WOT A/F is set at 11.3:1. To make better power and use less fuel you want this A/F to be about 12.5:1 for this type of vehicle.

2) Auto tranny shift points - There are tables that show at what speed to upshift and downshift as a function of throttle position. I have mine set up so that when you are just putting around the tranny upshifts sooner than stock to improve fuel economy. When you give it some throttle I have my tranny shift at higher speeds to improve acceleration. Properly picking tranny shift speeds can improve MPG.

3) Shift firmness is comprised of two elements: torque management and shift pressure. Torque managment is basically the reduction of timing when shifting to minimize the load on the drivetrain. Shift pressure is kinda how hard the tranny shifts gears. Increasing shift pressure doesn't necessarily reduce tranny life.

4) VVT - The PCM uses 5 VE (volumetric efficiency) tables to accomodate the VVT. My opinion why the 3.5L torque curve is flat is that the engine runs out of air at the upper RPMs. The 3.7L with VVT has its peak torque much higher than the 3.5L.