Converted my H3 to LS3 Monster!!

I am new to these forums and certainly new to any kind of computerized tuning. I purchased the HP Pro Tuner and I'm just plugging it in and familiarizing myself with navigating. I have not and I will not actually do any changes until I get more familiar with what I'm looking at. I had a local shop do the initial tune but they were having some difficulty getting everything right so I bought my own setup.

My project is my 2007 H3 Hummer which I have had the gutless 5 cyl ripped out and a crate 6.2 LS3 put in. The stock tranny was rebuilt with this high HP engine in mind.

https://www.youtube.com/watch?v=G4-nsVZC4dI

https://www.youtube.com/watch?v=uPKRfml0fyo

As you can see from that second video my biggest problem is with the jump off the line. The engine stumbles and doesn't really catch until it gets past 1500 rpm. I was told this is due to the very aggressive cam in this engine. It has gone through about 3 different "tunings" and the first time I drove this monster it literally jumped off the line. Then it changed and it could hardly get moving down the freeway so I took it back and they worked on the tuning some more and got it to where it runs pretty good but off the line stumbles.

Anyway, I'm not really asking for help with this specific project (as I have not provided any real info since I'm still trying to get familiar with the HP Pro) I'm just introducing my monster to y'all and sayin' "Hi".

I'll spend some time in the forums trying to figure out how to use my new tool (and of course I'd love any pointers for newbies)... I'll update as I make more progress.

almost sounds like a manual trans at takeoff kinda of a clunk like it was just put into gear (low RPM). Is the converter locking very low rpm? You have less than a 3.73 rear end like a 3.23 or 2.73? And that 2nd gear shift sounds sloppy... takes forever. LS3's are higher RPM engines due to the large intake ports and performance cam... definitely not cammed for low rpm torque monsters. I think my ported LT1 large cam 383 had way more off idle torque compared to this LS3 (my LS3 in my Camaro).

Theres a reason the automatics and usually trucks have VVT, to try to get more low end torque. The 420hp Silverado motor is not an LS3, it has VVT and uses that to get more low end torque, especially for towing.

I've played with my HP Tuner for a bit now and I'm starting to get the idea of it. To fix my tune problems I'm thinking of taking the 2014 Corvette file and copying over all the fuel and timing to my tune. Seems like it should work since the engines are almost the same. At least it might get me close enough so that I get the stumbling solved. For now that's my big issue.

Any thoughts for this newbie?

Well I tried copying all the settings from the Corvette and the car would not start. I then tried only copying over one area at a time and found that I can copy the fuel and spark setting over and the car runs better than before but if I try to copy the MAF settings then it won't start. I see that my MAF is quite a bit different than the Corvette for some reason...

I did find the setting for the gas tank which is all messed up on my tune so if anyone knows what these numbers should be for a 2007 H3 I'd sure appreciate your help.

Right now I'm going through my tuning book and trying to figure out how to get the MAF right. I think this might be where my stumbling is from but I am way to fresh at this to know if I'm even in the ball park.

A 2014 corvette is a DI motor and not a port fuel injection motor like you are running, so some thing should maybe not be copied over. Leave the MAF curve as you have it and tune it for your application, there is going to be no drop in and go curve.

Your camshaft makes everything different as well, the motor requires different amounts of air and fuel at any given time over what the stock calibration is set for.

The VCM scanner section has a few threads on tuning the VVE and MAF curve, you will need a wideband for tuning as well.

Quote:

---

Originally Posted by 5FDP

A 2014 corvette is a DI motor and not a port fuel injection motor like you are running, so some thing should maybe not be copied over. Leave the MAF curve as you have it and tune it for your application, there is going to be no drop in and go curve.

Your camshaft makes everything different as well, the motor requires different amounts of air and fuel at any given time over what the stock calibration is set for.

The VCM scanner section has a few threads on tuning the VVE and MAF curve, you will need a wideband for tuning as well.

---

Thanks, I'll check those out. - Also, how does one use wideband? I searched the forum and didn't find it.

A google search for wideband would be easier.

A wideband is a gauge to monitor air fuel ratio, something you must know on a modded engine. GM V8 engines run narrow band o2 sensors that do not function or make corrections during open loop or acceleration like WOT. So the things controlling the air to fuel ratio are whatever your airflow and fueling tables are set to and with a setup like yours it's not going to be correct. You use the wideband to make corrections to your airflow and fueling tables to make the engine run healthy and safe.

For example if you are commanding your stoich ratio of 14.68 while cruising and the wideband shows it running leaner around 15.5 you can create a AFR or Lambda error to log the vehicle and make corrections to the MAF/VVE to richen the air fuel ratio back to stoich. Also just why watching fuel trims, if the trims are rather positive or negative you know there is adjustments needed as you don't want the computer to compensate for everything all the time.

And again with WOT tuning, if commanded AFR is 12.3 but the wideband shows 13.0 there is a large error there. Adding fuel back in to the MAF/VVE would be the way to correct that and that's why the wideband is needed to see that.

A search shows there are Bosch wideband sensors out there for under $60. Some with gauges say they have wideband and narrowband outputs so you can connect the original connector to it as well. Would you recommend these Bosch units??

http://www.ebay.com/itm/Bosch-LSU-4-...VY~jWX&vxp=mtr

Also, I'm assuming I have to connect the wires to the strip on the side of my HP Tuner Pro and somehow assign the software to monitor those ports and interpret the data according to some table or graph?

You'll need the gauge/controller, not just the sensor. Then install it in it's own bung in the exhaust system before the cats if you are running them.

If your vehicle has CAN-BUS buy this wideband, even if it doesn't I'd still recommend this wideband as it's easy to use and setup with HP Tuners with or without can-bus. The pro interface can be used as well.

http://www.jegs.com/i/AEM/017/30-0333/10002/-1

I'm thinking about buying just the sensor and the converter since I don't have any intention of installing a gauge.

http://www.ebay.com/itm/PLX-SM-AFR-W...tY~opF&vxp=mtr

Do you see any issues with this? I again assume I need to wire something to the side connectors on my HP Pro so if there's any info on how to do that I'd sure appreciate info on how to do it. (quite the newbie on tuning but I'm trying to learn).

Waiting for my wideband to show up in the mail. In the mean time I have my tune file and my log file that I will upload here to see if anyone has time to give me an idea of how far off I am (I'm sure a lot). My biggest concern is to not do something that will ruin my new engine!

Attachment 74416
Attachment 74417

Thanks all!

A Wide Band Gauge on top of the dash is really, REALLY recommended.
This is a very important tool that you don't want to cheap-out on.
Just like you should be running the best premium gas you can find,
until you know for a fact that you are never getting into detonation, or too much knock retard in the ignition timing.
Possible Lean mixtures combined with too much timing on the highway at 80mph
can destroy your engine in just a few minutes, if the computer is not able to properly save the day.

Next item, You probably should have a higher stall speed torque converter for that engine.

And BTW, I'm an AnarchoCapitalist/Volluntaryist, welcome to the club.

I would consider a LS3 engine especially pulling that much weight a Premium Fuel only setup.

Quote:

---

Originally Posted by Jim Brown

A Wide Band Gauge on top of the dash is really, REALLY recommended.
This is a very important tool that you don't want to cheap-out on.
Just like you should be running the best premium gas you can find,
until you know for a fact that you are never getting into detonation, or too much knock retard in the ignition timing.
Possible Lean mixtures combined with too much timing on the highway at 80mph
can destroy your engine in just a few minutes, if the computer is not able to properly save the day.

Next item, You probably should have a higher stall speed torque converter for that engine.

And BTW, I'm an AnarchoCapitalist/Volluntaryist, welcome to the club.

---

I did get one with a gauge but I was only going to use it to make sure my calibration is correct in my HP Tuner setup. You are recommending I install this gauge inside where I can watch it during daily driving? Is it likely that my fuel mixture can get that far out without some indication other than the gauge?

#LIBERTY !!!

P.S. Ron Paul was right...

Any time you have an unusual swap, with all kinds of "I didn't know that matters", or "I was told that...", or "I know a guy who did it and he didn't have any problems", type of changes, there is always the possibility of some unplanned weirdness happening, and a Wide Band Gauge is going to alert you to most problems before they turn ugly.
After a year or so, with nothing out of the ordinary, you might want to call it "good".
But the gauge is not very obtrusive and lends a little bit of Hot Rod feel to your truck.
You may never need it, but if it saves your engine just once, it's worth having.
Mine sits right next to my cell phone holder on the dash where I can see it in my peripheral vision.

On a different note, you also need to tweak your transmission, silky-smooth shifts at full power will kill it quick,
especially with 3 tons of american iron you're trying to haul around.

Jim

Quote:

---

Originally Posted by Jim Brown

Any time you have an unusual swap, with all kinds of "I didn't know that matters", or "I was told that...", or "I know a guy who did it and he didn't have any problems", type of changes, there is always the possibility of some unplanned weirdness happening, and a Wide Band Gauge is going to alert you to most problems before they turn ugly.
After a year or so, with nothing out of the ordinary, you might want to call it "good".
But the gauge is not very obtrusive and lends a little bit of Hot Rod feel to your truck.
You may never need it, but if it saves your engine just once, it's worth having.
Mine sits right next to my cell phone holder on the dash where I can see it in my peripheral vision.

On a different note, you also need to tweak your transmission, silky-smooth shifts at full power will kill it quick,
especially with 3 tons of american iron you're trying to haul around.

Jim

---

Thanks for the tips. My wideband came to day and I'm going to put the gauge in the cab like you say. Had the guy who built the tranny take it for a spin today to make sure the shifts are firm enough. I like them firm anyway.

I'm assuming the biggest damage I can do to my new engine is by running it lean, am I right? As long as the ratio on the wideband don't go past about what, 15 or so, I should be safe??

Sorry about the delayed reply.
I'm the victim of some over zealous Sheriffs deputies (blatant lairs and criminals) and just got out of jail and got my truck out of impound.
For asking a question of a deputy, I was tasered and charged with "obstructing an officer"......
Anyway, to answer your reply, the Wide Band Meter, and the Air/Fuel Ratio that it shows are only a part of what can be damaging.
Actually, ANYTHING, or any combination of things that can initiate "Knocking" or "Detonation" without your knowledge, and/or,
without verification that your knock sensing system is operating properly and effectively, is the main concern.
It's just as important as engine oil pressure, possibly more important.
Having the engine go lean under heavy load is not necessarily "bad" all by it's self.
But a rich mixture under load, (around 12:1 to 13:1)
will not only make more power, it also "cools" the combustion temperatures and reduces the
tendency towards detonation.
So your ignition timing maps, and knock sensor settings, must match, not only the engine, but also
the relationship between the Torque Converter, rear end gears/tire diameter, and truck weight, and driving style.
(like for instance.... will you ever tow a trailer ??),
Is your cooling system properly matched to the engine and it's intended use ??
~15 degrees above the thermostat setting will seriously increase the risk of detonation, even if it's "just temporarily high".
Before you can mindlessly flog your new set up, you need to verify all of the above, plus a few other details I haven't mentioned.
At the very least, you should be running the best premium gasoline you can find until you are fully confident that the
engine will always be operating in it's "comfort-zone".
I'm not trying to scare you, but hard detonation can do permanent damage to the engine in seconds.....
not minutes.... seconds. And you can't always hear it in the cab, especially with a loud exhaust.
So, it's important to know that the mixture is comfortably "fat", (rich), when you've got your foot buried on the loud pedal.
.
Jim

I'm really sorry to hear about your encounter with the goons. I hope it all works out alright.

I am a bit concerned about knock as I'm not so sure my knock sensors are even working. In my log files I cannot find ANY instance of knock detection which to me is suspicious (although maybe I just don't now how to find it). I certainly don't want to be running without any means of detecting knock. How can I check to see if it's working properly?

Here's my last tune file and first log with my wideband.

Currently you aren't logging knock retard, thus it won't show up.

Your main channels list need to have knock retard in there for it to show up in the graphs and charts.

That looks like a pretty big issue...

So I looked under spark and retard and there's a bunch of things listed there. It looks like the best choice would be the first one which is simply called knock retard or the second one called total knock retard. Either of these though need to have a functioning knock sensor in order to "retard" so how do I set up a channel to simply show if I'm getting an actual "knock"?

Pick the one that just says knock retard for now. Once added to the channels list it will display knock there, it will display knock retard in the charts as you already have knock retard as a selected PID but it remains blank because it's not currently being logged. It should also display knock retard in the graphs as there is should already be a pre-made graph to log spark knock there.

As a newbie I have a dumb question that I can't seem to find in any of the forums but maybe I just don't know where to look. In my scanner my fuel trims are charted as KPa vs rpm but when I go into the editor I can only find VE Initial Correction Factor which is kPa vs coolant temp (under airflow, dynamic).

The only other places I can find that are similar are under Airflow, General and they are VE lo Altd ect charted as RPM vs TPS and all of these are zeros.

So where do I put the corrections for my fuel trims?? I've watched lots of videos and I think I'm finally understanding that the basis of any good tune is to get the VE correct (which in non-boosted engines should always be something under 1.0). Example: If my fuel trims show I'm +10 at 85 pPa vs 2400 rpm where would that correction go in my editor??

Sorry for the super basic question but believe me I've tried to find it and my tune file doesn't have any good option under "general".

Attachment 75072

https://www.hptuners.com/forum/showt...tarted-Threads

The fuel trim thread in here shows the step by step.

The VVE editor is under your edit tab. If you choose to edit the VVE first, you need to disable the MAF sensor in the tune to prevent skewed data. Most choose to do the MAF first, then work on the VVE later but it really doesn't matter what you do first.

Thanks for the fast response. I'll dive right into that thread.