Which cars had the M62 supercharger / LSJ Engine? Hunt your supercharger.

[mike_sno]

Hi all,

I am working my way into the supercharger world. I am checking or local U pull and play / find your part but they have currently no Chevrolet Cobalt SS on the lot.

I believe the M62 is used in many other cars. I can’t really find a list which cars either had the LSJ engine or the M62 supercharger. Is something like that existing?
For example this one https://www.gmpartsdirect.com/oem-parts/gm-supercharger-89018119 its from the Pontiac Grand Prix. Would that fit?

I hope to find a newer low mileage donor to pull a Supercharger from.

Mike

 

[jirwin]

05-07 Cobalt SS 2.0
04-07 Saturn Ion Redline

Other cars have M62's, but they have different blower cases and won't fit.

 

[snirtman]

Here's one source that shows which cars had Eaton superchargers . To fit one to a NA Ecotec engine you'll need an M62 intake modified to fit the Ecotec engine you're using, a different belt, different tensioner and different alternator at least. Then there's the tuning...

 

[mike_sno]

Seems like the Cobalt and Saturn are the only one with the Generation 5 M62. Will be hard to find that.

 

[Desert Sasqwatch]

The aftermarket will be your best bet, if the GM setup is not in the cards. Most aftermarket kits are pretty complete for the installation.

 

[Mahkoi]

This just popped up on market place out by me. Not sure what going price is but sound like what you are looking for.

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[Rauq]

For what's it's worth I'm not aware of a single supercharged LSJ out there not running the original integrated laminova-cored A2W intake manifold. On top of that manifold I've come across whispers of a Gen5 M90 being custom fitted on that intake manifold, but besides that, your options are GM Cobalt/Ion M62 or Harrop TVS1320.

OP you may want to move this to SS/SC discussion if you can, or at least out of the SS/TC specific forum.

 

[Robinjo]

Hi all,

I am working my way into the supercharger world. I am checking or local U pull and play / find your part but they have currently no Chevrolet Cobalt SS on the lot.

I believe the M62 is used in many other cars. I can’t really find a list which cars either had the LSJ engine or the M62 supercharger. Is something like that existing?
For example this one https://www.gmpartsdirect.com/oem-parts/gm-supercharger-89018119 its from the Pontiac Grand Prix. Would that fit?

I hope to find a newer low mileage donor to pull a Supercharger from.

Mike

If you join the Facebook Cobalt and Ecotec Classified groups these pop up from time to time.

 

[mike_sno]

@Rauq is it in the wrong sub forum? I started it in the SS/TC forum.

I thought about the M90 but wonder why you almost find no information about M90 on the 2-2.4L engines. My understanding it would spin slower, for the same boost and would be not as efficient. However in high boost it has more potential as it doesn't top out as soon as the m62. I think the TVs might be the best option.

Oil, bearings and general maintenance I can do myself. I found some companies online to rebuild a SC. However I couldn't find any information if they would do something to bring the clearance between the housing and roots back to factory specs. Maybe that's not necessary...?

 

[Rauq]

@Rauq is it in the wrong sein forum? I started it in the SS/TC forum.

I thought about the M90 but wonder why you almost find no information about M90 on the 2-2.4L engines. My understanding it would spin slower, for the same boost and would be not as efficient. However in high boost it has more potential as it doesn't top out as soon as the m62. I think the TVs might be the best option.

Oil, bearings and general maintenance I can do myself. I found some companies online to rebuild a SC. However I couldn't find any information if they would do something to bring the clearance between the housing and roots back to factory specs. Maybe that's not necessary...?

My bad, I'd forgotten there wasn't a SS/SC specific forum.

I don't know that the performance maps of each blower agree with that. They should produce the same pressure ratios (%, absolute manifold pressure / ambient air pressure) at the same flow rates if they're on the same motor; the relationship of flow to pressure ratio is a characteristic of the motor- that is, if you increase flow (move to the right on the map), you increase the pressure ratio (move up on the map). If you spin them the same, the M90 will obviously flow more, resulting in a higher pressure ratio and less efficiency, which means more heat.

If you really want to make more power than the stock supercharger, I don't think a bigger version of comparable blower performance is the way to go, it's with a blower with a better performance map, i.e. a TVS.

I don't really know anything about reclearancing these blowers.

 

[mike_sno]

Reading/seeing those diagrams made me believe I have to study this topic quite a bit more before. There is plenty of understanding missing. Did you get those diagrams from a book or so?

 

[Ross]

Matt Cramer wrote:
"These use two variables, pressure ratio and the air volume flowing into the supercharger. Pressure ratio determines boost, as these things multiply pressure, rather than adding it. If atmospheric pressure is 14.7:1 psi (it varies with altitude and weather conditions), a 1.5:1 pressure ratio would be 22.05 psi absolute pressure. Subtracting the original 14.7 psi gives you 7.35 psi boost.

The other variable is the inlet flow rate. It's given here in cubic meters per hour. Multiply that by 0.59, and you get cubic feet per minute.

Finding the point where these two meet, and the blue rings show adiabatic efficiency (the higher the number, the less it heats up the incoming air). The dashed green lines show how fast you have to spin the blower to get that number."

To convert the dashed green lines to engine RPM you have to divide the SC RPM by the SC pulley ratio.
The stock LSJ has a 6.18" crank pulley, and a 3.34" SC pulley, giving us a 1.85 pulley ratio.
To spin the SC at 13,500 RPM (top of the M62 chart), a stock LSJ would need an engine RPM of 7,297.
17000 RPM SC line is 9.189 engine RPM
15000 RPM SC line is 8,108 engine RPM
13000 RPM SC line is 7,027
12000 RPM SC line is 6,486
11000 RPM SC line is 5,946
10000 RPM SC line is 5,405
9000 RPM SC line is 4,865
8000 RPM SC line is 4,324
7000 RPM SC line is 3,784
6000 RPM SC line is 3,243
5000 RPM SC line is 2,703 engine RPM

 

[jirwin]

So working backwards...

If I'm running 12psi of boost, that's 26.7psi absolute. Which means a Pressure ratio of 1.81 (26.7/14.7). Assuming the LSJ has the same damper size as the LAP, with a 3.1" supercharger pulley I would be running a pulley ratio of 1.99 (6.18/3.1). That means at 7000RPM I would have a blower speed of nearly 14000RPM. If I'm understanding this correctly, that means that the TVS I would have to run out to only 11000RPM blower speed, and the M90 about 10000RPM to get the same volume of air (although it would be cooler air). The TVS would be massively more efficient with an adiabatic efficiency of ~72.5 vs the M90's ~58 and the M62's ~54. Am I doing that math right? I just matched up inlet volume after working backwards.

 

[Rauq]

Not a supercharger guru, just a guy who reads a lot.... but yes, that's the jist of it. The jump in efficiency from the M62 to the M90 is small compared to the jump to the TVS.

I'm not sure how to quantify efficiency, but lower efficiency generally means more heat, and that does very much coincide with reporting that M62's can be pulley'd down so far that that they stop making more boost and only make more heat. I understand that that's inherent to the design of roots-type superchargers. They don't actually compress the air, they just flow enough of it to create a pressure differential, and they can only create so much pressure before they start to "leak" backwards.

 

[jirwin]

I happened to find a Gen 5 M90 for sale nearby for dirt cheap. I was debating snagging it and fabbing up an intake, but it doesn't sound worth it after seeing all this.

 

[mike_sno]

For what's it worth, I put the Engine RPM over the Supercharger RPMs for different pulley sizes using Ross's calculation above.

 

[mike_sno]

I try to understand the efficiency charts above.

I would think that the areas are not completely flat and probably have a peak higher to the center of the same colored fields. But that’s not to important at the moment. If my target is highest power then:

Priority:

1. I would like to be in the highest pressure ratio. In other words, the upper end of the chart. More pressure=more air=more gas= more power.

2. I want to be in the area where the adiabatic efficiency has the highest number. This is the most efficient point of taking energy our of the crankshaft for driving the Supercharger.

The only thing I have influence of in the set up is the pulley diameter. With the pulley diameter I can calculate the supercharger rpm with s_rpm= crankdiameter/pulleydiameter * engine_rpm
or look in the graph posted above.

I try to combine that with the Supercharger performance graphs where the x Axis is in m^3/h.

Let’s imagine my engine runs with 6000rpm that means I should be able to calculate the airflow with: displacement * rounds per minute * 60min/h * pressure-ratio.

For the 2.0 LSJ that would be 1998cm3 / 1,000,000cm3/m3 *6000rpm *60min/h * 1= 719.28m3/h.

Does that sound right? This is the case if I had 0psi boost.
Pressure ratio 2 would be 2x atmospheric pressure.

I put that in a graph.

Since I am just talking about Volume of Air, I can ignore the temperature influence. Where I am not quite sure is the pressure ratio over RPM. I have it as a linear function. I want to say that the pressure ratio is not linear. It increases with rpm. How much, I don’t know. This makes me believe that my graph is simplified and I really have to look at the pressure ratio at a given pulley diameter at a given engine speed. (Would be nice to gather some of that data out of logs).

Anyway, I leave it right now, already having my brain twisted

 

[mike_sno]

I'm not sure how to quantify efficiency, but lower efficiency generally means more heat, and that does very much coincide with reporting that M62's can be pulley'd down so far that that they stop making more boost and only make more heat. I understand that that's inherent to the design of roots-type superchargers. They don't actually compress the air, they just flow enough of it to create a pressure differential, and they can only create so much pressure before they start to "leak" backwards.

This is a great explanation!

I think heat is a not avoidable side product of compression. More compression more heat. Has something to do with Thermodynamic, I really don't want to remember details from the University times We have to deal with heat and get it out as best as we can.

It makes sense to me what you wrote with leaking. This is probably the case why the SC has a sweet spot to operate as shown in the performance graph above.

Anyway reading more about it, I am not sure if this is correct.
2. I want to be in the area where the adiabatic efficiency has the highest number. This is the most efficient point of taking energy our of the crankshaft for driving the Supercharger.

The adiaabatic efficiency is inlet vs outlet temperature. I read somewhere that this would correlate to engery driving the compressor vs energy out of the compressor. But have to think more about that. Seems like I have to dig out the old books again.

 

[Ross]

I try to understand the efficiency charts above.
...
Let’s imagine my engine runs with 6000rpm that means I should be able to calculate the airflow with: displacement * rounds per minute * 60min/h * pressure-ratio.

For the 2.0 LSJ that would be 1998cm3 / 1,000,000cm3/m3 *6000rpm *60min/h * 1= 719.28m3/h.

Does that sound right? This is the case if I had 0psi boost.
...

Theoretically the pressure ratio is 1 when at 0psi boost, but not in reality.
A naturally aspirated engine spinning at 6000rpm will have a vacuum in the intake. You can watch the boost gauge and see it go down to -10 psi or -7 psi. You have to add some SC pumping action to get it back up to 1 atmosphere.

 

[mike_sno]

I made another assumption. Wide open throttle