GT3 squirters

[MST0118]

I’ve been thinking about whether there is any advantage installing GT3 piston squirters for a high revving air cooled motor and if they flow more oil or are superior to 964 squirters.

I noticed that at least one builder had installed them on a 1982 turbo case for a high revving short stroke motor. It seems that the turbo squirters of 1.5mm are probably smaller than GT3 squirters so the upgrade may make sense. However, not sure if there is any advantage to install these on a 964 case that already has larger 2.0 squirters.

I suppose my questions boil down to this:

1. Do GT3 piston squirters flow more oil than the 2.0mm squirters in 964/993 cases?
2. Are there any other issues installing these squirters in an air cooled case for high rpm engine?

Any thoughts or experiences with this modification are appreciated. I realize there are a lot of choices on squirters now including rebuildable squirters but just trying to get a feel on how GT3 squirters compare to stock squirters on 964/993 cases.

Thanks.

[VFR750]

Are you also planning on a gt3 oil pump?

Because the higher flowing squirters are going to need more volume on the pressure side and more scavenging capacity to suck up all that extra oil in the sump.

Also what’s the goal: race motor or street-track day?

[Catorce]

Lots of people are concerned about flowing more oil with their squirters, and I am not really sure of the reason for that, exactly. The biggest ones I make are 2.5mm which flow just slightly more than the stock 2.0mm ones the factory makes because of different internal geometry.

Porsche maxed out at 2mm EXCEPT in their race cars - they simply added a second squirter. My cases will have 2 per cylinder just like the air cooled GT2 and other race cars. I am not convinced it is worth it to have 2 per cylinder, but hey, enthusiasts believe in it so I will make it.

As to the GT3, WHICH GT3 are you talking about. The modern 9A1 motor has zero in common with the mezger cased motors

[MST0118]

Thanks for feedback. Yes, will be using a GT3 pump and building short stroke 66mm on a 964 case. Still in the planning/design phase which is why trying to figure out oiling modifications including squirters.

I like the idea of dual squirters, too, so that’s another alternative. I did see that Supertec installed GT3 squirters in its 9000 rpm 3.1 motor which is similar in character to the one I’ll be building.

Any idea on flow performance between GT3 and 964 type?

[Neil Harvey]

Just my 2c worth here.

Piston cooling is about the heat rejection required after the heat produced from the engines torque production. Has nothing to do with the engines RPM.

More oil in the crank case will create other issues that will add to the heat the cooler will have to remove.

A lot of myths are circulated about squirter size and numbers without the true understanding their need and downside.

For sure the later pumps are a good idea. Its like water pumps, you can never have enough. Too much scavenge can hurt in some engine by pulling too much vacuum and removing oil from where it need to be. In these engines that is never the case as these engines could do with more and most never run crankcase pressure at zero or below at anytime.

There are way more important areas to look at in these engines that are never given any thought or attention. Look at how the rod bearings are feed oil and why the center ones often fail first?
Where does this oil come from and what could be done to help provide greater volume?

Its pretty simple and basic. Take a look. Not hard to see.

[MST0118]

I agree 100% Neil. I’m looking at other modifications, too.

I would still be interested in learning more specifics about flow data for GT3 squirters as I haven’t found it anywhere.

[Catorce]

Again, define GT3.

[MST0118]

Catorce, I just checked the PET catalogs for the 2005 and 2010 GT3s online and see the following part numbers for squirters:

996.101.018.91 (2005 GT3-1 cat)
997.101.018.90 (2010 GT3-2)
997.101.018.91 (2010)
997.101.018.92 (2010)

The first two of these parts are superseded to the fourth part number listed (.92), which appears to be a 2mm squirter for about $50 and used on one side of the GT3 case. The third part number listed (.91) is also available and is used on the other case half and is less than half the price of the .92 squirter.

It seems that there was a change between 2005 and 2010 because in 2005, the same squirter was used on both case halves while in 2010 there seemed to be 2 types.

Since the 2005 part number was superseded to the .92 squirter and is same 2.0mm, I think that is potentially the correct one.

Do you know how any of these 4 squirters compare to the 993 splash valves? Perhaps they perform the same? The 993 squirters are priced slightly higher.

[Catorce]

Originally Posted by MST0118

Catorce, I just checked the PET catalogs for the 2005 and 2010 GT3s online and see the following part numbers for squirters:

996.101.018.91 (2005 GT3-1 cat)
997.101.018.90 (2010 GT3-2)
997.101.018.91 (2010)
997.101.018.92 (2010)

The first two of these parts are superseded to the fourth part number listed (.92), which appears to be a 2mm squirter for about $50 and used on one side of the GT3 case. The third part number listed (.91) is also available and is used on the other case half and is less than half the price of the .92 squirter.

It seems that there was a change between 2005 and 2010 because in 2005, the same squirter was used on both case halves while in 2010 there seemed to be 2 types.

Since the 2005 part number was superseded to the .92 squirter and is same 2.0mm, I think that is potentially the correct one.

Do you know how any of these 4 squirters compare to the 993 splash valves? Perhaps they perform the same? The 993 squirters are priced slightly higher.

I don't have as much experience with the squirters on the water pumpers as I have on the air cooled, but having said that, the case used on the GT3 is essentially a 993 case that has some modifications (no oil return holes, no fan strap housing, etc). Therefore, I do not believe the oiling system on the late mezger case is substantially different from the 993/964 case.

I am unaware of a squirter used in any 911 motor from factory that was greater than 2.0mm in size, because when the factory wanted more oil to the pistons, they simply added another squirter.

Sometimes, you can get too much oil and lower oil pressure. In Rod Pobestek's World Time Attack Challenge 968 that made 850 plus horsepower, he used two of my squirters per cylinder but they were only 1.5mm which correspond to a factory 1.0mm squirter. So more flow is not always better.

[MST0118]

Thanks! That makes sense.

[Walt Fricke]

MT -
Do you have one of Henry Schmidt's 66mm cranks, which have the large #1 bearing you need for the 964 case? Or is there some other way to deal with that issue?

[MST0118]

Walt, I’ll send you a pm on that question.

[Speedy Squirrel]

As far as cooling the piston is concerned:

The heat transfer to the piston crown is proportional to the mean piston speed, so RPM is definitely a factor. It is simply a question of number of explosions per minute - higher revs = higher average temperature.

The heat transfer is also proportional to power. Higher power = bigger explosions = more heat transfer to the piston.

Two spray jets are used in designs that make provision for cooling of the ring band and the under crown separately. This requires a specific piston design.