kisik

I am exploring some options to cool my oil which is approaching 250F at hot day. People driving on street don't need to be concerned. I do have 997 regular Center radiator 997 106 037 02 and 160F thermostat. I am using 8100 5x40 oil with regular changes.
Here are my options:
1. Add GT3 top vent to properly engage heat air management. Currently there are openings on the bottom of the bumper sending hot air back to engine. $160
2. Bigger GT3 radiator if fits (it is BEHR 168mm tall as opposed to 997's only 118mm tall). $300 for BEHR unit.
3. Air conditioner side condenser delete (right side only). LN guys have a kit. $450
4. Investigate larger oil to air heat exchanger. GT3 one is 997 107 025 90 doesn't appear to be bigger then 997 version. I don't have data. Anyone? $350
5. Replace side radiators for CSF. Gorgeous.$500/ps
6. Add 2QT of deep sump. Bill racing? $850
7. XP7 oil $120

Thoughts? Please provide real engineering data if possible.

cosm3os

Interested, however, I was at the track this Summer with a rep from one of the reputable engine builders we often mention on this board and he was not impressed with 250 on the hottest day of the Summer. My oil analyses would back that up.

I'll also add, I'm seeing the same oil temps as the OP without the 3rd rad (mine's bone stock).

user 72902

You can also add to your list to replace your ac condensers which are normally hammered closed. It will allow more air to the radiators. I did it and it lowered my water temps by 7 degrees.

3Series

3.8 DFI here. No 3rd radiator. I don't recall ever hitting 250 on really hot 95F-100F days, and I have 40-50 days with this car. Maybe 240ish based on the super accurate gauge in the cluster after 3, 25min runs and high sun around 1-2PM.

Flat6 Innovations

Note : DT40 was never developed for the track. For track service use an XP series oil.

3Series

I run Mobil 1 5W-50.

No need for discussion, that's just what I run. In a pinch I use 0W-40. I just change the oil after a couple days of fun. Meaning I don't really care what oil is in there as long as it gets changed regularly.

kisik

Thank you Jake for chiming in. I was hoping to get more valuable input and not just usual oil discussion. I like a solid input of 7 degrees for a clean condenser. A reputable racing shop suggested that a new oil cooler in front of the center radiator should be installed along with separated oil pump like from Tilden. Everything else will just slightly postpone temperature rise (like extra 2QT of oil). That seems like extreme. For those not hitting 250F that is just a matter of time when they hit a car hard enough. Would opening up a vent on the top of the bumper be a better thermal option? I am just looking for best $$ per T degradation.

alexb76

Well, why don't you start with the cheaper options before going after expensive ones. One thing for sure is your oil, 5W50 for track should be an easy change to see if that helps, the GT3 vents are also a cheap mod that could help... why don't you start with that and see if you still need to mod further?

Wayne Smith

Is 250 a problem? 275 I might worry about, but 250 on synthetic doesn't seem like cause for concern.

wjk_glynn

That's what I thought as well (about modern synthetics)...

Karl.

BillNye

I don't want to start a pissing match, but it sounds like this racing shop may be giving you some mis-information. Based on a brief google search, the only oil pump that I can see made by "Tilden" is for an LS engine. I'll hazard a guess this isn't a prepared track car and, as such, adding an oil cooler in front of the center rad is probably not advisable. Unlike most racing Porsches, which have an engine that is designed to be dry sump, both of these things would be somewhat typical in something like a Corvette.
In order to add a cooler in front of the center rad you're talking about adding 10ft+ of custom plumbing from the back of the car, to the front, and back again. All that extra plumbing adds in a ton of potential failure points and also make oil changes a giant pain. Furthermore, adding an external oil cooler with that much piping may result in a pressure drop that the factory pressure pump can't compensate for.

In my experience with other engines, I would not recommend that you make too many large changes to an otherwise stock oiling system. VCT systems can be somewhat sensitive to oil pressure and flow conditions, and adding plumbing that drastically changes these could present other issues.

As to the vent in the top bumper, you'd have to add the accompanying GT3 ducting before any air would get up there in the first place. This is purely speculation, but on the GT3 that vent is likely instead of the vents on the bottom of the bumper, not in addition to. The GT3 would ideally be venting to the top for aerodynamics and not enhanced cooling. High pressure air coming from the radiator and exiting over the car would produce less lift.

JAGMAN1

I concur with Billnye. I’d say your realistic choices are to either clean out or replace your existing condensers or to replace your existing radiators with the larger version. Odds are your existing radiators are clean as they’ve been protected by the condensers.

Beyond that I don’t think 250 is excessive. Normal autobahn temps for me are 230-240 in sustained high speed cruising at 125+.

Tj40

The top vent option may not give you as much as you hope for. GT3 front center radiator is mounted in a different location to the 'stock' 997.2 3rd radiator - it's further forward and tilted forwards to give an airflow path through the rad and up towards the top vent. Now you will undoubtedly get more airflow opening the top vent and punching some holes in the airguide top behind the radiator (and I'm assuming that you will then have top and bottom venting) but unless you change out all the mounting pieces and airflow buts you are not getting the same as in the GT3.

Having said that for $160 it can do you no harm :-)

Lvt19672

Who is telling you that 250 is a problem???

kisik

I truly appreciate all the inputs. This discussion is not about if 250F is a problem or not (you can have your own personal opinion), but rather to collect some wisdom as to how to successfully lower oil temperature not spending too much money. So based on some investigation I slightly altered my list:
1. Remove bumper and clean all radiators and condensers. Check venting air dynamics between current bottom exit vs possibly top.
2. Condenser delete (right side only). Not for Arizona
3. Add 2QT of deep sump w/vantage tray. Bill racing or Mantis
4. XP7/9 oil
5. Investigate external small oil cooler (direct most effective but not straight forward). Using spin adapter and additional plate for fitting. Possibly extra thermostat to avoid too much cooling.