Anybody tweak your truck with HPtuners?

**Cutlass** · 09-25-2011, 05:12 PM

Originally Posted by pajeff02

Are any of you guys playing with DOD engines?

No not yet, but I've been reading a bit of that stuff here and there and its adds a little more complexity to tuning. But there are people out there doing that and trying things to get better gas mileage. Is your Suburban DOD?

**pajeff02** · 09-25-2011, 05:17 PM

Yes it is. Still under warranty, so I am on a countdown to when I can play with it.

**Firebirdjones** · 09-25-2011, 05:18 PM

Originally Posted by pajeff02

Are any of you guys playing with DOD engines?

If you knew me Jeff, I wouldn't have to tell you that I prefer to stay away from that stuff

I prefer simple over complicated. That's why it took me so long to find a low mile 6.0. It had to be from 05 on back, because the newer stuff had displacement on demand or variable cam timing stuff. All that stuff equals "much more expensive" too. I wish you luck though

**pajeff02** · 09-25-2011, 05:28 PM

Going to start simple and probably go with a catback for now.

**Firebirdjones** · 09-28-2011, 12:04 PM

Filled up today. First mileage check after the tuning session I had over the weekend with it.

It got 17.42 MPG on this tank, with strictly around town driving, alot of stop and go. That's the best it's ever done so far. I usually see low 16's consistently so I can safely say I picked up a solid 1 mpg increase with this SD tune.

I'm commanding the same 14.7 AFR in my tables that the 02 sensors hunt for. My guess is that since the 02 sensors aren't hunting around so irradically it picked up a little mileage.
Before with the MAF working my AFR's were all over the place.

I have both STFT's and LTFT's disabled at this point and the MAF is turned off running in SD mode, and strictly running off of the commanded AFR in the main table. Much better throttle response, crisp, and it feels like more grunt right off idle as well.

I'll take a highway trip this weekend down to Phoenix, and since I've seen 19 mpg highway on a regular basis, I'll assume this 1 mpg increase should put me over the 20 mpg mark on the highway. We'll see.

I also switched back to the stock 02 settings on this tune, so no fuel tuning tricks yet. There might be more in it

**Cutlass** · 09-28-2011, 06:05 PM

That's pretty sweet! You should be able to pick up some better mileage with some leaner cruise fueling and maybe more aggressive Decel Fuel Cut Off.

**REVNORR82** · 09-28-2011, 08:15 PM

Has anyone put any dyno numbers down yet im very interested in seeing what's up and as far as a burn out I have a 07 classic z71 and can lay rubber with a air raid intake an shitty cat back can't wait for the warranty to run out headers and ory and new exhaust and a tune are in my future

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**Firebirdjones** · 09-29-2011, 08:14 AM

I never have been interested much in chassis dyno's. The only time I used dyno's extensively is when building an engine, and while it's there it's convenient to toss it on the dyno for breakin and initial tuning.

From there I use the track for final tuning.

For what it's worth I have seen bone stock 6.0's on an engine dyno before, with just tuning they hit between 360-370 HP at the flywheel. That's with the truck intake and all.
Depending on the truck it's in it wouldn't be a chassis dyno queen anyway, pushing through a 4L80E and alot of them 4x4's so a transfer case as well.

**REVNORR82** · 09-29-2011, 08:29 AM

I have heard of people with 5.3 putting down 300 rwhp with a 4x4 just wanted to see if it was possible.

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**Firebirdjones** · 09-29-2011, 03:14 PM

Originally Posted by REVNORR82

I have heard of people with 5.3 putting down 300 rwhp with a 4x4 just wanted to see if it was possible.

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It could be possible. Since a 5.3 would have a 4L60E behind it, that's a slight advantage there as far as RWHP numbers. Any bolt on mod you can throw at it would surely help. Depends on how far you want to go.

**REVNORR82** · 09-29-2011, 03:18 PM

All I wanted to do is headers and ory I didn't know if I could change up the intake or not

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**Firebirdjones** · 09-29-2011, 03:26 PM

If it's in a truck, the only intake option is the FAST truck style intake. Which I hear does an excellent job.

It would be a real pain to switch over to a passenger car FAST or even an LS6 intake because the truck accessory drive mounts everything up high, and it's in the way. You would also have to swap the entire accessory drive system with a 4th gen setup or something similar.
Not really worth the hassle if you ask me. The stock truck intake is a decent performer from what I've seen. Long runners promotes torque, and you need torque with a little 5.3 in a big truck.
Actually in a dyno comparison from a few years back, the truck intake hangs right in there with the LS6 up to about 5,000 rpms. Then the LS6 takes over.

**Cutlass** · 09-29-2011, 06:39 PM

I got 15.2mpg doing my daily driving routine which is a mix of interstate and stop and go traffic. Its my best mileage so far but I'm not sure the fuel mileage trick is the reason or just my lack of aggressive gas pedal pressure. I think I'd benefit more from a real deal tune. I'm budgeting for a LC1 Wideband now...
I'm also working on a little secret project for my truck, but I'm embarrassed to even mention it. It might look completely ridiculous, but I'm collecting Escalade 22" wheels and tires to throw on my truck. So far I have 4 tires and 3 wheels. But one of my wheel is a Platinum edition 22 and the other ones are the standard Escalade 22". So, yes, flame me if you'd like. I agree it may look stupid and if so I'll just sell the wheels to someone else.
Here's a pic of someone else doing it:

**Cutlass** · 09-29-2011, 06:40 PM

Judging by the picture, I almost like it. But I'll have to see what it looks like in person before I really decide.

**Firebirdjones** · 09-29-2011, 07:27 PM

I think that could work Cutlass. On a 4x4 with an aggressive tread pattern it really doesn't look too bad.

**Firebirdjones** · 09-29-2011, 07:50 PM

I think a wideband is going to be the key for you to get some accurate tuning done. I've used mine for years on carburated stuff.
Using it in conjunction with HPtuners is a real eye opener.

Right now I'm not using that fuel mileage trick with the 02 sensors. I'm running completely off of the commanded AFR tables in open loop EQ ratio mode. That table is your commanded AFR vs engine temp for all cells,,,,similar to your VE tables vs rpm.
I put 1.0 in all the cell blocks so that it commands an AFR of 14.7 at all times, then I log VE AFR % error with the wideband and fill as many VE blocks as I can. (It took me 4 hours

) Once I was happy with that I did several full throttle runs which pretty much fills in the 75-80 g/cel row. Since I had my PE commanding a 12.8 AFR it gave me that percent of error when the PE kicked in.
That was it. I left it like that, with the MAF failed, running in SD open loop mode, which basically isn't using the 02 sensors even though they are still working. I got my best mileage to date with the truck as I mentioned.
I've been running my wifes camaro like this all summer. It's also got the best mileage ever. What I'm finding with the tune set this way, is that the AFR isn't hunting around as much, it's exactly where I set it in VE and it stays there.

For a mileage trick,,,with this tune, rather than trick the 02 sensors into a leaner AFR (they aren't being used so you can't) If I am thinking right I can simply go back to my open loop EQ ratio mode and change the commanded AFR to somthing like 15.3 AFR for example.
I can change only the cells where I am at part throttle cruising in overdrive, say from 55-70 mph (what ever those cells might be, I'd have to log it again) Then look at my VE table AFR % error and simply change those blocks where I commanded a 15.3 AFR.
Then I would have a leaner AFR at light throttle cruise, which is basically doing the same thing as tricking the 02 sensors, accept I think this way is much simpler and much more accurate.

I think my mileage improvement is proof of that. Since I am doing nothing but commanding a stock AFR right now (14.7) and this truck is doing the best it's ever done on MPG.
I am going to go through a couple tanks of gas before I make those changes just to get a good average of MPG first, then I'll log again and change the cruise cells to a commanded 15.3 and see what that does.

**5.0THIS** · 09-29-2011, 10:52 PM

Originally Posted by Cutlass

Judging by the picture, I almost like it. But I'll have to see what it looks like in person before I really decide.

I have factory ('08-'10) GMC 20 inch wheels on my 04 rcsb. I love them, but I dont think I'd ever put a bigger wheel on the truck. 22s are going to look huge. I am also running the stock size 275/55-20s. A bigger tire might help with the 22s, but that's still a huge wheel.

**Firebirdjones** · 09-30-2011, 12:54 PM

Maybe that picture is deceiving. They really don't look all that big. Or maybe it's just because a full size truck makes the wheels look smaller. In the picture they appear to look like 17's or 18's.

I know when you put 22's on a car you sure do notice it

**Firebirdjones** · 09-30-2011, 12:55 PM

I'm doing the opposite. I'm picking up a set of stock 15" steel wheels tomorrow to paint white and throw some dog dish hubcaps on my blazer

**Cutlass** · 09-30-2011, 07:36 PM

Originally Posted by Firebirdjones

I think that could work Cutlass. On a 4x4 with an aggressive tread pattern it really doesn't look too bad.

Exactly.

Originally Posted by 5.0THIS

I have factory ('08-'10) GMC 20 inch wheels on my 04 rcsb. I love them, but I dont think I'd ever put a bigger wheel on the truck. 22s are going to look huge. I am also running the stock size 275/55-20s. A bigger tire might help with the 22s, but that's still a huge wheel.

Definitely one of my concerns. I'm gonna go for it and see if its looks ok or stupid anyways. I have to try it. I've seen a few trucks around here with Tahoe 20s and I thought it look odd at 1st bit still kinda liked it.

Originally Posted by Firebirdjones

Maybe that picture is deceiving. They really don't look all that big. Or maybe it's just because a full size truck makes the wheels look smaller. In the picture they appear to look like 17's or 18's.

I know when you put 22's on a car you sure do notice it

22" look bigger on cars and 2wd trucks, for sure. but on a 4x4 truck/suv with a 32 or 33 inch tire they definitely don't look as big. Plus I've noticed, the design of the wheel can make it look bigger than it really is. A deeper dished 22 would look strange on a truck, i think.

Thanks all for the feedback!!