Looking at the M62 lower intake manifold, it appears that a pair of pipe plugs installed in the manifold would prevent coolant going to the throttle body via the supercharger'* casing.

Bypassing the coolant flow to the throttle body is a pretty common trick on the TPI and LT1 V8 motors to keep the TB from being heated by the engine coolant. Just wondering if anyone has done this mod yet and how well it worked out.

The two engines you mentioned don't have superchargers heating things up. This is a totally different ballgame.

I'm doing some testing to see if it'* feasible, as the coolant may have a cooling effect for our overly-hot TB'* and SC'*. Without the coolant, we may actually run hotter.

Totally different application, actually.

I'm moving this to Performance and Brainstorming, as it'* discussing coolant bypassing, not Forced Induction.

Hmm, if the intention of GM was using the passage to cool the SC, then they sure picked the wrong end to plumb it to. Based on the position and size, It looks like the intention was to use the coolant to preheat the TB only (so as to prevent the possiblilty of icing the throttle blade.) Not as an effort to cool the TB and SC. The place to do that would be on the output side of the SC or in the lower manifold itself.

TB icing is the concern on cold starts for all vehicles, but it'* also ideally located for SC cooling. I have thermal analysis on the M62 as well as temperature sensors all over mine. The hottest portion of the SC in operation is the inside face of the inlet directly behind the TB.

Good thinking on GM'* part if you ask me.

That makes no sense at all. Where'* the heat coming from? It can't be from the SC, since the heat from that is at the middle and output side where the air is actually being compressed. Is the heat comming from the EGR gasses perhaps?

*shrugs shoulders*

Some of the heat bleeds over from the nosedrive end from friction. Makes sense.
Some of the heat is produced by compressing air in the rotor housing. Makes sense.
Some of the heat is produced by the needle bearings on the end of the rotors by the TB.
Some of the heat is produced by the EGR valve, but not much.

The bulk of the heat produced under boost is from the inlet of the SC as all that air has to squeeze down to enter the inlet of the SC. This is compounded by the rough-cast surface the Eaton Superchargers have from the factory.

Under normal driving conditions, the SC may not heat up to the point that the coolant would be beneficial, but under high-boost runs at a dragstrip, my research shows the coolant to be beneficial in aiding the cool-down of the SC, as the temps spike very high after a run at WOT. A cooler thermostat with a larger opening helps some with this. The cooldown occurs much more quickly with the right selection of thermostats.


The cooler surfaces are a darker color. The hotter surfaces are lighter. Note the inlet.

This is why I started working on this:



It bypasses the coolant at the LIM and provides a seperate cooler source to continue the flow and remove heat from the inlet area of the SC and TB.

I have not built it, but have done some thermal dynamics testing on the model, and plan to do more. The expense is far more significant in the other work involved to make it fit, rather than the machining.


In this pic, you can see one of my temperature strips. There are a total of 8 of them on the SC and TB so I can track the temp flux through the top end.

That intercooler would be a huge benefit to the S1'*. Would the coolant be plumbed into the factory lines somehow or have it'* own coolant tank? I bet you could also inlcude watier injection setup with that too, though you like yours before the rotors, not after. Also, how much would that affect the small stuff like belt length and injector rail?

Awesome work on the thermal map too. That helps explain how so much sludge got built up in the lifter valleys of my motor (aside from poor oil and neglect)

It'* not an intercooler. It'* a thermal isolation plate that also seperately cools the SC and TB.
It affects the fuel rail, belt path, and alternator bracket. That'* the worst part. Seperate pump and radiator.

I'm not sure what sludge you're talking about or how this may or may not affect it. Sludge is very uncommon in our motors, and even cheap oil won't cause it. Normally it'* a function of a lack of oil changes.

[quote="willwren"]I hope this isn't considered hijacking, but here is my explanation to this. When I tore my LIM off, there was tons of crap under there. Lack of oil changes would explain why there was, but I really only noticed the sludge in the upper regions and no where else. My thought was that since the LIM of */C motors get as hot as your research shows, it would accelerate oil degredation, when the oil splashes up against it. Something similar to coking, a big problem for turbochargers that rely on engine oil for both lube and cooling. (in fact, alot of this stuff I scraped out DID look like coking) I am guessing an engine that is constantly running too hot will do the same thing too.

I've had my LIM off twice. Never seen any sludge.