GM High Value LZ9 Swap? (Page 4/11)
ChuckR AUG 30, 07:49 AM
While researching the possibility of a much later planned boost application I came across this from the 60degreeV6 website.


quote
what we do when we apply boost to late model gm vehicles is we get a map sensor for a chevy cobalt ss or a c6 zr1 corvette and we use hptuners to convert the ecu to a 2 or 3 bar os. and now the ecu can see when the intake manifold is under boost. and there are extra breakpoints added for those higher kpa levels. then we tune the ve tables in the newly added reigons and then we tune the maf. and the ecu works the same way it did from the factory, just now it uses boost. the right way. the other way is the canned tune way. it forces all fueling off of the maf. while a lot will argue this method works, I would like to point out that to date not 1 car has left a manufacturing plant tuned like that. every boosted oem application the ecu sees boost. tuning shouldn't be about what you can get away with, but how good you can get it.



This is in response to someone asking about boosting a 3900VVT. Is it that simple? I know that you have to take these things on forums with a grain of salt.
Dennis LaGrua AUG 30, 09:51 AM

quote
Originally posted by ChuckR:

While researching the possibility of a much later planned boost application I came across this from the 60degreeV6 website.


This is in response to someone asking about boosting a 3900VVT. Is it that simple? I know that you have to take these things on forums with a grain of salt.


It looks like common sense to me. You cannot safely run a boosted application without a two/three bar map unless it employs a MAF sensor based PCM that uses the VE tables as only a fall back option (like on the 3800SC}.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

ChuckR AUG 30, 11:55 AM
So for instance the 3900 is VVT, so would the flashed OS need to have those options as well? Also the 3900 does not have a wide band O2. so does this mean with the reflash you can use a wide band from a Cobalt? It just seems like there is a lot more to it than refalsh your ECM with one that has a 2 or 3 bar MAP. I asked Darth Fiero about boosting and he said:

quote
It is possible the factory 3900 ECM (even with DBW) could be custom tuned to work with a turbo. But these ECMs didn't use a wideband o2 sensor, and that would be preferred in any serious turbo build.



Is this how you can use the factory ECM? I am trying to wrap my head around the hows of it.
wftb AUG 31, 10:28 AM
You do not need a 2 or 3 bar MAP sensor for the ECU to see boost. A maxed out 1 bar map sensor is at about 8 psi of boost on my guage in the car compared to what the ECU is seeing. The OS on my car does not have a MAF sensor, many newer OS's have both. So the ECU will read from negative manifold pressure at no boost to 1 bar or about 8 psi when boost gets that high, and everything in between. So, you can set up your tune based on that, with things like taking off timing starting at about .8 bar and going from there. After you get to the point in the MAP/timing/rpm table where you know it is over 1 bar you just go to the high rpm part of the table and pretend the ECU is seeing 2 bar if that is close to what you are going to set boost levels at and set the timing accordingly. And check all the tables that also reference MAP readings and make changes as needed.
For VE tables on my tune I don't mess with them. There is a VE offset that stock is set at 20%. Change that and all the tables change. I run at 50% with the 20G mitsu turbo I run. The other thing to change is the rpm that the Power Enrich function comes on at. On most NA cars that is set very high, 5500 rpm in my case. I have that set at 2500 rpm and there is a table to set AFR vs RPM in PE mode so you can compensate for the lack of a 2 bar there as well. There are other tables that can be fudged with too to help in high boost situations.
In my case I can not mount a wide band and hook it directly to the ECU because there is no input for one. To use a wide band, I have to send its signal in to my HP tuners interface and then see if I am getting the results I want with a scan. Since I can't set AFR except under PE, I have not bothered hooking one up.
Intake air temperature (IAT) readings usually have a direct impact on timing and other tables as well, even on an NA engine. So a good intercooler is a necessity. And relocate the IAT so it is reading temps after the intercooler and before the throttle body.
I am by no means an expert tuner. Most of what I have done is just what other people have done and posted on HP tuners forum. If you have HP tuners you can download other peoples tunes as well. Makes it easy to see what works and what does not work.

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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

Will SEP 01, 08:57 AM

quote
Originally posted by wftb:

You do not need a 2 or 3 bar MAP sensor for the ECU to see boost. A maxed out 1 bar map sensor is at about 8 psi of boost on my guage in the car compared to what the ECU is seeing. The OS on my car does not have a MAF sensor, many newer OS's have both. So the ECU will read from negative manifold pressure at no boost to 1 bar or about 8 psi when boost gets that high, and everything in between. So, you can set up your tune based on that, with things like taking off timing starting at about .8 bar and going from there. After you get to the point in the MAP/timing/rpm table where you know it is over 1 bar you just go to the high rpm part of the table and pretend the ECU is seeing 2 bar if that is close to what you are going to set boost levels at and set the timing accordingly. And check all the tables that also reference MAP readings and make changes as needed.
For VE tables on my tune I don't mess with them. There is a VE offset that stock is set at 20%. Change that and all the tables change. I run at 50% with the 20G mitsu turbo I run. The other thing to change is the rpm that the Power Enrich function comes on at. On most NA cars that is set very high, 5500 rpm in my case. I have that set at 2500 rpm and there is a table to set AFR vs RPM in PE mode so you can compensate for the lack of a 2 bar there as well. There are other tables that can be fudged with too to help in high boost situations.
In my case I can not mount a wide band and hook it directly to the ECU because there is no input for one. To use a wide band, I have to send its signal in to my HP tuners interface and then see if I am getting the results I want with a scan. Since I can't set AFR except under PE, I have not bothered hooking one up.
Intake air temperature (IAT) readings usually have a direct impact on timing and other tables as well, even on an NA engine. So a good intercooler is a necessity. And relocate the IAT so it is reading temps after the intercooler and before the throttle body.
I am by no means an expert tuner. Most of what I have done is just what other people have done and posted on HP tuners forum. If you have HP tuners you can download other peoples tunes as well. Makes it easy to see what works and what does not work.






If it's actually reading boost, it's a 2 bar sensor. A 1 bar is only good for atmospheric. Either way, your gauge is wrong.
wftb SEP 01, 01:14 PM
People forget that without boost the intake is under negative pressure. To get to 1 bar in the intake manifold takes about 8 psi on my setup. There is nothing wrong with my guage. I think I am not wording this right, what I mean is it takes 8 psi of pressure in the tube that goes from the turbo to the throttle body to get the ECU to see 1 bar in the intake manifold. And since a MAP sensor is reading Manifold Absolute Pressure (pressure in the intake manifold after the throttle body), a 1 bar MAP will show the intake manifold under boost with a limited range. My boost guage and all my reference points for water/meth etc are connected directly to the intake manifold after the throttle body.

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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

[This message has been edited by wftb (edited 09-01-2019).]

BillS SEP 01, 06:07 PM
Might want to look at the recent Ecotecs, although the 3.9 is also a logical swap for the Fiero.

The 4 cylinder Ecotecs in turbo form are physically smaller, lighter engines that offer up to 400 bhp with very little work - don't even need to do anything inside the engines. There are threads around here on people that have done the non-turbo version as a Fiero swap to give you an idea of what is involved.

I have a mildly tuned one (375 bhp) in a 3,000 lb. Solstice that will do just under 13 flat in the 1/4 yet gets 30 mpg (highway) when driving normally. I've always thought that using one in a 300 lb. lighter Fiero would be rather interesting....
fieroguru SEP 02, 10:42 AM

quote
Originally posted by wftb:

People forget that without boost the intake is under negative pressure. To get to 1 bar in the intake manifold takes about 8 psi on my setup. There is nothing wrong with my guage. I think I am not wording this right, what I mean is it takes 8 psi of pressure in the tube that goes from the turbo to the throttle body to get the ECU to see 1 bar in the intake manifold. And since a MAP sensor is reading Manifold Absolute Pressure (pressure in the intake manifold after the throttle body), a 1 bar MAP will show the intake manifold under boost with a limited range. My boost guage and all my reference points for water/meth etc are connected directly to the intake manifold after the throttle body.



Pressure and vacuum are relative to the reference point.
Atmospheric pressure is always present and is 14.7 psi or 101kPa and varies with elevation and temperature/humidity changes.

Turn a car on, engine not running and the MAP will read in the 95 to 100 kPa range (measuring atmospheric pressure). This is 1 BAR and this is the highest reading that most 1 BAR MAP sensors are calibrated for.
Run a NA car at WOT and you will also be in the 90 to 100KPA range. A good debate question is how does air get into the engine? Is it being sucked in by engine rotation or pushed in via atmospheric pressure? There definitely is a 14.7 psi force pushing air into the NA engine, but the pumping motion of the engine can exceed the inlet flow of air (seen as less than Key On KPA reading).

When a NA engine is idling it can see 40 to 60 kPa. This is less than atmosphere, but would still be pressurized around 7 PSI, so the manifold isn't in a true "vacuum or negative pressure" state only a lower pressure state. It is very, very difficult for an engine to reach 0 kPa (even engine braking at 7000 rpm with the throttle closed) and you need to reach this point to create a true vacuum (zero atmospheric pressure) and go beyond it to create a negative vacuum state.

When people refer to boost pressure, it is in relation to atmospheric pressure. 7psi boost = 21.7psi actual. 14.7 psi boost = 29.4 psi = 2 BAR.

So if you want to accurately measure boost pressure in the 1-15 psi range, you need a 2 BAR map sensor, boost pressure in the 15 to 30 psi range needs a 3 BAR.

Many of the later model GM ECMs/calibrations have factory tables that go beyond the 1 BAR range and allow tuning for boost with the proper MAP sensor. Instead of the basic RPM x MAP timing table, most now use RPM x cylinder airmass for timing and hopped up NA applications barely use half of the table.

[This message has been edited by fieroguru (edited 09-02-2019).]

wftb SEP 02, 02:45 PM
Here is a screen shot of what I see on my laptop while taking a scan:



We have gotten way off topic but you can see the MAP is reading boost.

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86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

ChuckR SEP 03, 05:38 AM

quote
Originally posted by BillS:

Might want to look at the recent Ecotecs, although the 3.9 is also a logical swap for the Fiero.

The 4 cylinder Ecotecs in turbo form are physically smaller, lighter engines that offer up to 400 bhp with very little work - don't even need to do anything inside the engines. There are threads around here on people that have done the non-turbo version as a Fiero swap to give you an idea of what is involved.

I have a mildly tuned one (375 bhp) in a 3,000 lb. Solstice that will do just under 13 flat in the 1/4 yet gets 30 mpg (highway) when driving normally. I've always thought that using one in a 300 lb. lighter Fiero would be rather interesting....



While I respect the Ecotec engines and their capabilities, I wanted to stay with the 60* V6 engine line. Frankly I like the way they sound. The Ecotecs are not so great sounding to me. Since there are 1001 ways to swap and make power I am going to keep the overall sound of the car as a factor. While I am asking about boost right now, I am planning an NA swap. My boost questions are in case the NA swap just isnt enough for what I am looking for at a later date and I want more power what all would be involved. Which sounds like if I want to boost the 3900 properly I will have to stand alone ECU, and cam it since I would most likely be loosing VVT with that set up. Though wftb is boosting on an NA set up and it is working well, I think the MAP and wideband O2 would necessitate the engine management change from what I am reading from Fieroguru and what Darth Fiero had told me in PM. I know the 3900 can be boosted. There is a thread out there in the F body forums where a guy is posting 10's on the 3900 in a 3rd gen Camaro. I believe Joseph Upson also has a boosted 3900, just trying to see what it takes to get there.

[This message has been edited by ChuckR (edited 09-03-2019).]