I figured it was worth the effort to start another thread as we had two diverging topics mixed in one.
We left here:

"Not that I'm aware of ... I'm thinking SS sheet bolted in place, I'll just have to drill and tap the LIM and then seal the threads to prevent any leakage. Or make a valley tray/LIM gasket as you mentioned.

I'd love to take the time to digitize the bottom of the LIM so I could create a solid model."


I can tell you on the turbo 3.8 Grand Nationals that the lifter valley pan is integral and snaps in place with the bottom of the head with the port seals rising up from there.
I'll take a pic'.

Here you go.
The gasket is upside down in these pic's.
You can see the oil drain back slot in the ends of the middle,downwards bow.
You can also see the "punchouts" and where they hook onto the bottom side of the installed heads.
This style won't work with the balance shaft in the lifter valley as well as the 3.8's having a 1" higher block deck height.
Whta the guys do when using the Felpro 1200 intake gaskets [for full race sized ports,no lifter valley pan shield-this gasket in the pics is a Felpro 96033],is trim this gasket to clear the 1200's leaving just the tabs and a bit on the manifold faces to hook under the heads and stay firmly in place.
It looks like on the 3800 you'll need a pan shield to go flat across with similar tabs to locate the thing.
You *should* be able to make it "just" snap in place.

Maybe this'll give you some ideas:

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2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

Yea that looks like it might work if it was formed to sit flush on the heads as well as the engine deck.

If it could be sealed off, the open area between the gasket and the LIM could be filled with insulation (aircraft grade)

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Under Construction

I don't know if I'd put in any insulation,but a shield would go a long ways towards stopping any hot oil from splashing against the bottom of the LIM.
The problem I see with insulation is that it could soak up oil.

_________________
2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

you could make one that would be sweet. i do not think a buick turbo 3.8L one will work though seeing as the engine has a 1" taller deck hight then the series two but if you could make it work that would be sweet

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92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater

Eeyup,the 1" deck height difference was covered in my original post.
Once you trim off the port sealing area,you may want to slice it down the middle lengthwise and rejoin it to suit the engine.
That would probably involve bending the area upwards a bit just under where it butts under the heads and flattening the arch in the middle section of the valley to clear the balancer.

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2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

Well,so far we've figured that keeping hot oil from warming the LIM is a good idea.
Usually you try to help inlet flow with bigger,better breathing air inlet systems [Wizair,K&N,etc.].
You can port the outlet/inlet on the supercharger to allow the air to exit/enter to the manifold/supercharger easier.
Can you think of anything else?
Maybe something to allow the rotors to fill easier at varying pulley RPM's [smaller pulley diameters]?
There's going to be a large amount of air turbulence going into those rotors when they start to really spin up and that will create inlet flow losses and heat [you'll be getting closer to the choke flow limit of the supercharger and out of it's efficiency band].
That should lower air inlet temps to the rotors and allow the blower to breathe easier making it more effficient at what it does [lower heat generated during the pumping phase].
Any ideas?
Don't be scared to stick in your two cents worth here.
What may seem like an outrageous idea *might* just have some validity.

_________________
2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

By the time the oil gets to that point, I doubt its MUCH hotter than the coolant that already circulates in the LIM. I hate to crap on the idea, but I don't think it will lower temps much considering the coolant in the LIM gets 190*ish depending on thermostat.

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This would require a lot more work but I haven't seen anyone do this as of yet. Polish everything starting from the filter of the intake pipe (a fender well would probably work best for this application) through the TB, including the S/C and into the LIM. By polishing, I mean a mirror shine, that is the best way to lower heat by reducing the amount of friction the air is encountering on the way into the motor and allow for much better Laminar flow. Much beyond what you are suggesting is going to quickly approach the operational limits on how much can be done with this S/C without changing the rotor type in the casing. An I/C is a must for this application as well since you are putting a little distance between the heat source and the S/C. Also, what about changing the actual casing material? This is getting into high dollar amounts but these are just ideas right? For racing applications, using a metal with a high specific heat would be most beneficial since it has a slower rate of heat absorption as opposed to aluminum or iron. The S/C would stay cooler for a longer period of time there by reducing HP loss due to heat.

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2009.5 SBM G8 GT
November 2011 Car of the Month

After looking at the LIM pics,I would have to agree with you.
Looks like GM was shooting for maximum fuel efficiency.
I would guess that the best way to cool the LIM would be to do any porting you might want to do and have it thermal coated in the plenum/runner area.
An IC is a good idea on a boosted engine,but you're still going to pick up heat from the LIM,even after the charged air is cooled.
There's no getting around that,even if an IC puts you in a better position temps wise.
Time for bed...more to come tomorrow.

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2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

Finally,some time to get back to this thread.
Your idea of polishing the inlet sytem to a mirror finish isn't bad,but it will pay diminishing returns compared to working the supercharger itself.
What never ceases to amaze me is the guys who throw a 3" inlet kit on a 4" factory intlet.
I never quite understood the logic.
When it comes to inlets on boosted engines,the bigger,the better....especially where longer lengths of inlet are involved.
The reason is that nature likes things in balance and hates a vacuum.
When the rotors pump air into the manifold,they create a low pressure area at the inlet that the surrounding atmosphere tries to fill.
The smaller the inlet tract,the harder the "void" is to fill......especially when the 'charger spins up and starts pumping more and more air.
There comes a point however when the rotors affectively "cavitate" [I believe that's the term] and reach a point where they can't effectively pump anymore air in because because of turbulence at the inlet of the 'charger.
As you approach that point,that's where you see outlet temps rise.
So what do you do about the inlet turbulence?
How do you fill the rotor voids more effectively at higher 'charger speeds [RPMS]?

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2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

I think the only way to avoid this problem would be a storage tank (like on a well water system), I believe thats why GM made the air box so large on these cars. Tha air gets drawn in and fills the box and the motor draws from the box. Obviously the system is flawed once you start drawing more air than is stored.

Stepping back a post or two, it was mentioned that the collant (190*) heated the LIM so at minimum any isolation from engine would yeild 190* air going into the cyclinders. I'm wondering if TBC coating would work to isolated that heat if applied in the water jackets of the LIM.

Basicly the TBC would be applied to the bottom of the LIM and to internal passages of the LIM.

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Under Construction

What about doing what a lot of blowers do and seal off the stock opening on the S/C and open up the top like a lot of blowers do. That would allow for much less restricted air flow and you could open up the LIM as well. Again this is another high dollar job but you go back to the whole "cheap, reliable, fast" and you can only ever have 2 of them.

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2009.5 SBM G8 GT
November 2011 Car of the Month

That's the first idea I thought of too,but why not just coat the plenum and runners?




Okay,I'll bite...why feed in the top instead of in the end?
You're on the right track with the problem,if you're thinking the way I think you're thinking.

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2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

Let's look at what happens to the air as it travels into and out of the supercharger.
First it enters the air inlet and travels through the airfilter,inlet plumbing system and to the mouth of the 'charger.
It then finds it's way into the rotor gaps [passing a few "obstructions"] and is swung around the inside of the case towards the bottom [outlet].
Just before it gets there,it passes over the silencer slots which allow some manifold boost pressure to enter the rotor gaps which helps to equalize the pressure between the 'charger air and the manifold plenum boost.
That cuts down on pulsation noise making the system more desirable for Joe Average.
It then exits out the bottom creating an "overfill" or boost situation in the plenum.
What bothers me the most is the "obstructions the air meets up with when it enters the rotors.
That's where the turbulence is created the most and so the greatest heat.
If the air could get into those rotor gaps with a lot less drama,you would probably find the 'charger to be a lot more efficient at what it does and the $6,000 Whipple kits would be not nearly so desirable....not that many people would fork that kind of money for one anyway,they usually go turbo.
Here's some picks I've grabbed off the net for comparison's sake:

I'm guessing we could smooth/polish the airway by power honing ... the same could be done with the LIM.

I like the idea of the top mounted TB ... this would drastically reduce the turbulent air flow through the system

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Under Construction

On your first point,a good polish with a Dremel tool should do fine.
Why not keep the stock inlet and just rework it so the rotors fill better?

I got thinking more about the top load inlet tonight and there is a downside to it.
If you look at the profile of the rotors from the end,you'll see a backwards curve to them.
As the rotor turns towards the case to trap air,the air is going to push up and over the tip of the rotor as the rotor speed increases.
Look at the pic' of the Whipple rotors.
They're more vertical on the one rotor.
That should help alleviate the rollover condition.
It also looks like one of the Whipple rotors does a lot more air "pumping" than the other.

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2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

^^^ This is probably the reason why they designed the rotors the way they did. I bet they had this same discussion many moons ago and came up with the idea of changing the design of the rotors. How large can one really open up the stock S/C on that side? The TB seems to be a bit of a choke point unless you hack off the end of the S/C and open it up to the size of the actual diameter of the casing. Of course, you would need to fabricate an entirely new TB to that size and shape. Not sure if that would allow air from the LIM to re enter the S/C casing more easily unless you port the LIM into a rectangular shaped opening vice a triangular one.......
Also, what about welding up the silencer ports? I haven't heard a lot of discussion on this and I know it makes more power but you get more noise with it also....

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2009.5 SBM G8 GT
November 2011 Car of the Month

I'm looking at the second last picture I posted and wondering if that can't be shaped with any detrimental loss to the 'charger [similar to the last pic..left inlet]?
That peak sticking down can't be doing any good judging by the fact they actually sell an insert to work around that problem.
That peak looks like it has it's highest point about halfway through the rotor gap's rotation in the window.
I think it should be laid back at around 45 degrees and beveled or rounded
You could work on the front edge of the "eyebrows" as well,tapering the profiling off as you go towards the outside.
Thoughts?

_________________
2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

I think that peak is pretty important since you need very little space between the rotors and the casing in order for air to be pushed down into the LIM. Take that away and you will start developing a lot of turbulence there and lose efficiency.

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2009.5 SBM G8 GT
November 2011 Car of the Month

I thought about that and I wonder: A top feeding 'charger doesn't have that there period and they seem to work well.
I also look at the fact that the rotor is only halfway through it's "fill cycle" when it reaches that peak.
Even blending the peak might only remove 5% of the seal distance along the rotor and that's only halfway through it's cycle past the bottom of the feed opening.
I'm thinking any *slight* loss in seal at that point should be more than made up for by the extra fill rate.
I got thinking about the silencer slots as well and I think the reason they work slightly better when filled in is because the rotors are squeezing out lower pressure air into the plenum ... denser air should be harder for the rotors to squeeze out...agreed?
Filling in the slots would be hard to do right because the filled area would have to be machined to match the case in order to avoid air turbulence when the rotor gap passes over the filled area.
So here's an idea:

Since the slots tend to lower efficiency a bit,why not put them to work for you?
In other words exploit them.
What I'm thinking is to bevel the outer edges of the noise slots towards the outside of the case [as viewed from the bottom .. 'charger upside down].
The insides of the slots would be beveled inwards towards the center of the case [inside].
That should give you two parallel walls that focus their force towards the center of the case and help to push the rotors around when they go by the slots instead of shooting straight up into the rotor cavity.
What do you think?

_________________
2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

With the first part of that statement you don't need the peak in the middle because your source of air is on top of the rotors and is completely open to the incoming air so it doesn't give it a chance to develop any turbulence. Change the position of the source of air and it is a completely different story...

For the silencer ports, I think that is the reason why a lot of people will close them up because that is just another source for pressurized air to re-enter the S/C and decrease efficiency. If anything, open up that outlet completely so you eliminate those ports completely thereby maximizing total output from the S/C.

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2009.5 SBM G8 GT
November 2011 Car of the Month

To your first statement:I agree however I'm not advocating milling the whole peak out,just a little profiling of the nose of the peak.
Where a 'charger can suffer a loss of efficiency is when the rotor to case clearance gets loose all the way around or the rotor tip to root clearance gets too loose...too much internal pumping loss.

As to you second point,two things happen:

The boost gets exposed to the incoming charge sooner and in a much greater amount,which will lower efficiency somewhat.
That's why they went to a V shaped outlet.
The noise will rise a lot more too.

_________________
2005 GT owner [Non S/C] with a "big DIC".
Two years later and I still love the car.
Thanks Pontiac...Bleen is keen!

I was assuming that we would keep the V shape but just enlarge it to encompass the silencer ports but I definitely see what you are saying. What about looking at the gearing and find a way to make the rotors spin with a lot less effort than it has to now? Make the rotors and gearing out of a much lighter weight material? I am open to ideas....

Here is a Gen 4 MP90 from Magnuson. Thoughts?
http://i.ebayimg.com/09/!BN1cB(QBmk~$(K ... kg~~_1.JPG

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2009.5 SBM G8 GT
November 2011 Car of the Month

When it comes to gears,good old Steel works the best.
Good catch on the Magnuson.
I like the extended slot.
I have been wondering why guys like to port the outlet with a flare on the bottom instead of the inside?
It would seem to me that you would want the air to have a nicely shaped ventury to exit from instead of rolling over a sharp edge and flaring out on the bottom side.
With the sharp corner on the bottom,it should act kind of like a mechanical "diode" to prevent flow reversion up into the outlet.
Like this:

There's no way in heck I'd ever buff that far into the case though.
That's just plain amateurish.
I would be inclined to bevel that opening a lot more though.

I recently visited Intense Racing while I was on vacation and got the three hour tour.
There's some interesting stuff going on there.
It seems the inlet peak gets treated the same way on both their styles of 3800 'chargers.
The second one is a pic of an Intense 'charger inlet.
The first is a pic' of a Steg' inlet off a Cobalt 'charger.