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2007 AWD 3SS
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Discussion Starter #1
Edits code that HPT does not have access to.

It's a long story...

I first had superchips do beta testing on my 07, it made a huge improvement all around but shifting was too hard, no torque management and not much change in low rpm performance.

I was at Superchips and noticed their techs were using hex edit to directly modify OEM code to make changes, so I kind of had that suspicion.

After getting home I read the car with HPT and saw the changes that were apparant, and decided to change what I didn't like. That went very well, got it all tweaked at low rpm's, timing and dwell and shifting. Had it pretty well done and happy.

I thought I'd try it on my bud's avalanche, so I put mine to stock with the superchips and then loaded my modified programming from HPT figuring it should have had the superchips code in it plus my changes. Then I noticed it blows a little fuel smoke on revving the motor that I did not notice before removing the actual superchips programming.

Looks like I'll be doing more investigative work to figure out for sure. Right now I have the superchips loaded into the avalanche, so it might take a little while to get to the bottom of it but I have to wait to see my bud again, who is out of town this weekend. I may just put his back to stock with superchips and instead just directly use HPT to modify his settings so I can play with the superchips base code again on mine.

BTW: I am still trying to get to the bottom of the throttle opening all the way. I did notice the last 20% of accellerator pedal has no effect on the scanning, so it has nothing to do with physical travel on teh gas pedal sensor itself. I think we will have to petition HPT to figure out where that code is for max throttle allowed and incorporate a table or correction for it in the programmer software so we can get full throttle.
 

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BTW: I am still trying to get to the bottom of the throttle opening all the way. I did notice the last 20% of accellerator pedal has no effect on the scanning, so it has nothing to do with physical travel on teh gas pedal sensor itself. I think we will have to petition HPT to figure out where that code is for max throttle allowed and incorporate a table or correction for it in the programmer software so we can get full throttle.
:2cents:

Not sure why you think you're not getting full throttle, because you should be.

Normally, on an electronically controlled throttle (ECT) you use ~15-20% of the throttle movement for idle and decel air control (since you don't have an IAC).

What is reported in the data stream is the movement BEYOND the idle control "area".

SO... if you see 17% throttle with the key on/engine off, you should expect to see 83% at WOT (i.e. 100-17 = 83).

If you go pull the intake tube off and have someone floor the throttle, you'll see:

  • 83% TPS (various sensors, A, C, etc.)
  • 100% Commanded Throttle (Actuator)
  • 100% Pedal Position
  • PHYSICALLY the actual throttle blade will be fully open

This is the convention when dealing with ECT (whether it's a forklift, a boat, or a car) from my experience.
 

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2007 AWD 3SS
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Discussion Starter #3
You haven't kept up with the story Ken.

The max throttle body position is not reached at 83% TPS reading.
You can test it for yourself.

Physically at 83% throttle the blade is NOT fully open. You check it, I already have. Full open places the TPS% at 88% reading. The TBSS is the only LS2 that has this limitation, the Corvete LS2 actually opens all the way and the TPS% reads 88%.

I have tested both.
 

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The Worlds my Playground
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You haven't kept up with the story Ken.

The max throttle body position is not reached at 83% TPS reading.
You can test it for yourself.

Physically at 83% throttle the blade is NOT fully open. You check it, I already have. Full open places the TPS% at 88% reading. The TBSS is the only LS2 that has this limitation, the Corvete LS2 actually opens all the way and the TPS% reads 88%.

I have tested both.
The LS2 in the SS sits at a slightly diff angle than the vett, also the Vet / SS have diff intakes therefore diff idle/throttle %'s.. EFI shows ~83% at wot on mine.
 

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You haven't kept up with the story Ken.

The max throttle body position is not reached at 83% TPS reading.
You can test it for yourself.



Physically at 83% throttle the blade is NOT fully open. You check it, I already have.
I did too ... mine is fully open at WOT (and shows about 83% TPS ...). The throttle body is at a slight angle on the truck manifold so maybe that's what you're seeing?

If it isn't fully open (I didn't get out a protractor and make sure it's a 90 degrees to the plane of the TB throat :biggrin2: ), then it's close enough to be inconsequential, IMHO.

What am I missing?

Did it on the GTO too, and it's fully open.
 

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Maybe a bit tough to see, since I couldn't get the camera perfectly square to the TB (cheapy digital, so it doesn't like being too close). Anyway, IMHO it's fully open?

 

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Discussion Starter #7
Maybe a bit tough to see, since I couldn't get the camera perfectly square to the TB (cheapy digital, so it doesn't like being too close). Anyway, IMHO it's fully open?

Full open to me is right angle to the throttle body bore where the physical stop is. If you take yours to 83% TPS then you will notice it will open a small amount more and the reading will go to 88% TPS.

BTW: The GTO and the C6 goes to 88% TPS with full throttle blade opening, but don't take my word for it.
 

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The Worlds my Playground
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Full open to me is right angle to the throttle body bore where the physical stop is. If you take yours to 83% TPS then you will notice it will open a small amount more and the reading will go to 88% TPS.

BTW: The GTO and the C6 goes to 88% TPS with full throttle blade opening, but don't take my word for it.
Bro, we drive TBSS's, not vetts and gto's... As stated above, these vehicals have diff setups. Im not exactly sure why you are set on squeezing out that extra 5%, because it wont happen....:cheers1:
 

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Bro, we drive TBSS's, not vetts and gto's... As stated above, these vehicals have diff setups. Im not exactly sure why you are set on squeezing out that extra 5%, because it wont happen....:cheers1:
I tend to agree ... kind of "picking fly shit out of the pepper" ... :cheers1:

I'm looking at it pretty closely (with the pedal full depressed for quite awhile ...) and don't see any physical stop in the bore? The picture is at a slight angle, but if I could get the camera lined up I think it would be at 90 degrees to the bore ... or so close as to be hard to measure?

I guess from my experience with working with ECTs, you usually don't want the mechanism hitting any physical stops, because it tends to wear/stress the gears/motors in the mechanicsm. Usually you do a full travel calibration and then give yourself a small amount of play to avoid hitting the stops.

I've never seen any measurable HP loss attributed to this practice, but then again we characterize the TB and set the cals to it.:2cents:

Not arguing, just telling you what I see and have experienced ... :wavetowel2:
 

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Discussion Starter #13
I know Ken, just razzing you a little.

Ken's a good guy who usually stays open minded, so I can't really fault him.
 

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Edits code that HPT does not have access to.

It's a long story...

I first had superchips do beta testing on my 07, it made a huge improvement all around but shifting was too hard, no torque management and not much change in low rpm performance.

I was at Superchips and noticed their techs were using hex edit to directly modify OEM code to make changes, so I kind of had that suspicion.

After getting home I read the car with HPT and saw the changes that were apparant, and decided to change what I didn't like. That went very well, got it all tweaked at low rpm's, timing and dwell and shifting. Had it pretty well done and happy.

I thought I'd try it on my bud's avalanche, so I put mine to stock with the superchips and then loaded my modified programming from HPT figuring it should have had the superchips code in it plus my changes. Then I noticed it blows a little fuel smoke on revving the motor that I did not notice before removing the actual superchips programming.

Looks like I'll be doing more investigative work to figure out for sure. Right now I have the superchips loaded into the avalanche, so it might take a little while to get to the bottom of it but I have to wait to see my bud again, who is out of town this weekend. I may just put his back to stock with superchips and instead just directly use HPT to modify his settings so I can play with the superchips base code again on mine.

BTW: I am still trying to get to the bottom of the throttle opening all the way. I did notice the last 20% of accellerator pedal has no effect on the scanning, so it has nothing to do with physical travel on teh gas pedal sensor itself. I think we will have to petition HPT to figure out where that code is for max throttle allowed and incorporate a table or correction for it in the programmer software so we can get full throttle.
I had my '07 in to Superchips for their testing as well but had it put back to stock before they gave it back. I just got the updated Flashpac and programmed the truck and noticed an immediate improvement across the board but wasn't too thrilled with the 1-2 shift firmness so I backed it down to 10% over stock and it's close to perfect now. It's possible it could use a little more timing in the lower RPM's but it did improve from stock. I use a bridge here as a test, it's a 35 mph bridge with a pretty good incline so it's a good test of part throttle response and power. I use about 10% less throttle to maintain constant speed and throttle response is faster than stock by a significant amount.

When I was at Superchips I asked about HPT. Aparently they had a deal with the people at HPT but broke off the relationship a while ago. In their opinion HPT got more out of the deal than SC so it wasn't in their best interest to continue the relationship. I also confirmed that SC uses basic hex editing of the source program based on their years of reverse engineering. I suspect they dig into some areas that HPT can't get to and that they didn't give HPT all of their secrets.

I'm very satisfied and considering I can put it back to stock, modify shift firmness, shift points, rev limit, speed limiter, tire size and axle ratio It's a far better deal than sending the ECM off to someone's garage or basement or spending the time to learn HPT..... Add to that the Towing program, 87 octane program and data logging capabilities what's not to like? FYI, I'm not new to EFI tuning but the TBSS is a daily driver / people hauler. If it were one of my Porsche's then I might feel different about taking more time to dissect the internals of the ECM....
 

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2007 AWD 3SS
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Discussion Starter #16
Yeah, I definitely like my Superchips tune, but being able to modify it with HPT turned out to be a real godsend for low speed driveability. It actually feels like a big V8 now at low speeds, much improved over superchips. (I did not change the Superchips WOT settings, those are great for now, considering I don't have access to an AWD dyno to play with)


How much has your mileage increased? I went from 11-12 MPG to around 15, nice little gain.
 

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Discussion Starter #18 (Edited)
Guess that's no good for what I thought it was. That value is the PCM readout of throttle position, really insignificant to me.

Apparantly I'll have to use hex edit on the hpt file and find the value for the throttle max position so it will go all the way open. Any clues?
 

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erm...I'm pretty sure Superchips owns hpt. The real question is whether or not the tables that reference TPS in the tune are actually ETC. For example, our pe enable tps is 87%.. In this case.. we'd be kinda screwed. Another one being for transient fueling.. whats the delta referring to ETC or TPS? Could it be the way our tb is mounted? It definately looks slanted and not perp to ground level. Have you been able to turn the blade to read out 0% TPS?
 
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