Topic: The magical gmpp tune

[shabby]

For those that don't have the gmpp tune but have hptuners i suggest you install it asap, the 3bar sensors you can get from performance autowerks http://www.performanceautowerks.com/catalog/product_info.php?cPath=334_165_221&products_id=1712 and the gmpp tune can be found on the hptuners repository. They have a 2007 gxp 5spd tune and a 2008 redline 5spd tune, if you're wondering if the 2008 redline tune will work on your 2008 solstice one person on the hptuners forum installed an hhr gmpp tune on his cobalt and it worked so most likely the redline tune will work on your solstice. Otherwise beg someone for the exact gmpp tune you need.

So what will the gmpp tune give you? The ability to command much higher boost and airflow with ease. The first pic is a log of a stock gmpp tune on 2nd is of my modified gmpp tune, the numbers on the side are both @ 6000rpm in 3rd gear. The increases in boost, cylinder airmass and maf lbs/min are staggering seeing that the gmpp tune already puts out 290hp/340trq.
The changes that i made to the gmpp tune are minor at best, the desired airlow table gets bumped up to 260%(you can set this lower if you're not feeling comfortable) and the 4 timing tables only get an extra 1.5 degress past 5000rpm. Peak airflow numbers that i've seen so far are 41 lbs/min... from the stock turbo. Mods are intake/exhaust/cat/intercooler.

[tazz]

I can also upload the GMPP tune for a 07 auto GXP in the tune repository.

[Kelu]

Nobody will upload an Opel GMPP  
That airflow screams very high 300 crank hp, so high than I'm afraid to say how much, am I right?  

[kennysabarese]

This is pretty huge!!!! I am a Wester's customer, just bought 2 weeks ago and the first few tunes he gave me went into limp so he started over from scratch and has been slowly been upgrading mine. I am currently getting 34 on the MAF, but my tune is still not finished.

My full intent with these dumb questions is to learn as much as possible and help others to learn.

From what I heard over and over again on this forum, Lyndon has struggled to get the GMPP tune up to give more power than his 2.7 sensor tune.

Also do you think your mods are making much of a difference? Shabby pipes?

[shabby]

I can also upload the GMPP tune for a 07 auto GXP in the tune repository.

The more gmpp tunes on there the better, thanks for sharing.

That airflow screams very high 300 crank hp, so high than I'm afraid to say how much, am I right?  

That's what i'm thinking, if the gmpp tune flows 30lbs/min and puts down 290hp then with 41lbs/min it must put down... a crap load more.

Also do you think your mods are making much of a difference? Shabby pipes?

I doubt the shabby pipe does much for hp, its mainly for an external bov and maf relocation.

[Kelu]

Question, actually is more a confirmation: Stock GMPP log was made in same configuration of mods?

[kennysabarese]

That's what i'm thinking, if the gmpp tune flows 30lbs/min and puts down 290hp then with 41lbs/min it must put down... a crap load more.

Does anyone know what the bone stock 2.7 max MAF is?

According to Garret it's 9.5-10.5 per lbs/min which would be like at least 390 if you are making 41lbs/min

But, with GMPP stock I was getting 32, which at 290hp would be more like 9 instead of 9.5-10.5, so either my GMPP is making more than 290 because the torque rules are not as strict, or someone smarter than me please fill in the blank.

[shabby]

Question, actually is more a confirmation: Stock GMPP log was made in same configuration of mods?

Yup same mods, only the tune changed.

Does anyone know what the bone stock 2.7 max MAF is?
According to Garret it's 9.5-10.5 per lbs/min which would be like at least 390 if you are making 41lbs/min
But, with GMPP stock I was getting 32, which at 290hp would be more like 9 instead of 9.5-10.5, so either my GMPP is making more than 290 because the torque rules are not as strict, or someone smarter than me please fill in the blank.

On a stock car with no mods i've seen 28 lbs/min tops.
That 30lbs/min was at one specific rpm point and it wasn't the highest reading, if i moved the slider around it went up and down and i did see 32lbs/min in there too.

[kennysabarese]

Also your boost levels seem very low in HP Tuners, can you explain this? I get 22psi on the DIC (~240MAP in HPT) I didn't have boost setup on my early GMPP setups so I can only compare MAP

[shabby]

But at what rpm? Im getting 21psi at 6000rpm, between 2800rpm and 5500rpm its off the chart, actual boost is higher since hptuners can't read above that.
Also don't take boost numbers too seriously, its the airflow numbers that matter most.

[kennysabarese]

Yeah sorry. I didn't look closely enough to notice that those numbers weren't at peak boost.

And I was hoping you might have figured out how to get HPT to show boost properly. I heard there is a way to have it calculate it properly from Kelu, but haven't looked any further into it.

[shabby]

You have to run the 5v output from the gmpp sensor into the hptuners mpvi pro box, then make a custom pid to change the voltage reading into a boost reading. I plan to do this eventually.

[kennysabarese]

doh. I wasn't planning on getting the pro box, since I wanted a more proper track logging application with GPS and accelerometer. *shrug* a boost gauge sounds easier

[Kelu]

About boost reading, how the DIC it shows 25psi with stock 2.5bar sensors?

[kennysabarese]

Also don't take boost numbers too seriously, its the airflow numbers that matter most.

According to the Garrett article, which I assume you are familiar with, both MAF and PSI are important in achieving power goals.

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html

[elff]

This is very curious.  All we have seen over an extended period of time is some tuning that hasn't been able to eclipse tunes without the GMPP tune and hardware.
What's the difference in what you are doing?
If the gains are this significant, are these mods putting the engine in a potentially unsafe state in which damage can occur?

[shabby]

About boost reading, how the DIC it shows 25psi with stock 2.5bar sensors?

They're 2.7bar rather than 2.5 so they can read 25psi.

According to the Garrett article, which I assume you are familiar with, both MAF and PSI are important in achieving power goals.

When two cars are running 20psi but one is making 40 more hp then the other its the the airflow numbers that tell you that, not boost. Not saying its irrelevant, i just don't put much emphasis on it.

If the gains are this significant, are these mods putting the engine in a potentially unsafe state in which damage can occur?

Hard to say, but if other are running 400rwhp+ then im far from making any damage with the stock turbo. Im really not doing anything special, just posting my findings with the gmpp tune, maybe my mods are just right for it and are giving me these crazy results, who knows.

[kennysabarese]

When two cars are running 20psi but one is making 40 more hp then the other its the the airflow numbers that tell you that, not boost. Not saying its irrelevant, i just don't put much emphasis on it.

Yeah I agree with that statement. I am trying to find the best way to compare cars and who is making the most power so we can all learn together. I think the logs are the most consistent way to compare cars.

 

[tazz]

One thing I've noticed while comparing and viewing the tables that are unlocked via HP Tuners(wish all of them were unlocked but I'm not holding my breath) from different tuners is that most richen up the power enrichment lambda table a bit from stock.  Is this because most tuners feel that GM runs the tune a bit too lean for there liking and are playing it safe since not all the tables are unlocked or has it been shown that with the 2.0L it makes more power slightly richer?
Most vehicle's that I know(not DI engines) run the other way around where they are running pig rich from the factory and the tuner leans the tune out a bit to make more power. Maybe GM does this for a reason and the engines likes a lean mixture better?
Thoughts

[2kwk4u]

Yeah I agree with that statement. I am trying to find the best way to compare cars and who is making the most power so we can all learn together. I think the logs are the most consistent way to compare cars.

 

I'm relatively stock with a GMPP tune (only other "power" mods are a drop-in K&N, cat-back and a minor wastegate rod adjustment).  I don't have HPT, but I recently bought a DashDAQ from another member here.  I'd be happy to log/upload some runs if it helps compare.  It'll help me learn how to use the DashDAQ better anyway. 

Unless I'm missing it, though, I don't think I can log everything that Shabby has in his OP.  For example, I can't find PIDs in the DashDAQ for int/exh cam angles.  I've figured out the rescale calculator for AFR and Boost, though...

[NormSky]

Where does 40 lbs/min land on a Garrett efficiency map?


Norm

[kennysabarese]

Where does 40 lbs/min land on a Garrett efficiency map?

Check this out

http://www.squirrelpf.com/turbocalc/

[kennysabarese]

One thing I've noticed while comparing and viewing the tables that are unlocked via HP Tuners(wish all of them were unlocked but I'm not holding my breath) from different tuners is that most richen up the power enrichment lambda table a bit from stock.  Is this because most tuners feel that GM runs the tune a bit too lean for there liking and are playing it safe since not all the tables are unlocked or has it been shown that with the 2.0L it makes more power slightly richer?
Most vehicle's that I know(not DI engines) run the other way around where they are running pig rich from the factory and the tuner leans the tune out a bit to make more power. Maybe GM does this for a reason and the engines likes a lean mixture better?
Thoughts

I am not a tuner myself at all, but I know that you can bend rods by going too rich. Dunno if it has anything to do with DI or not.

[shabby]

Is this because most tuners feel that GM runs the tune a bit too lean for there liking and are playing it safe since not all the tables are unlocked or has it been shown that with the 2.0L it makes more power slightly richer?
Most vehicle's that I know(not DI engines) run the other way around where they are running pig rich from the factory and the tuner leans the tune out a bit to make more power. Maybe GM does this for a reason and the engines likes a lean mixture better?
Thoughts

Ya everyone thinks that gm is running it too lean, but also everyone is not familiar with direct injection and gm's reasoning for doing so. Im sure they've done their homework though, i mean they're offering a 5year/100k warranty on the engine with such a "lean" afr.
The engine definitely likes a lean mixture, it runs 14:1 afr upto 4500rpm, normally that would be suicide on an evo/sti but not on our cars.
I leaned out my afr a bit in the midrange too, the pulsewidth was though the roof before.

[Sol Asylum]

I am not a tuner myself at all, but I know that you can bend rods by going too rich. Dunno if it has anything to do with DI or not.

I'm not sure how you are going to bend a rod by going too rich unless by too rich you mean the cylinder is full of fuel and you have a liquid lock.  The fluid won't compress as the piston is forced up to TDC and then the rod will bend.  But if while an engine is running and the mixture is enrichend you will flood the engine and it tends to run like crap if it stays running at all.