What's the 'next step' oil cooling mod for my 3.4L Carrera?
 

Guys,

In 10 short days I should be driving my 3.2 to 3.4L '87 Carrera for the first time this year, and more importantly, with an engine that runs reliably :) Displacement has been changed from 3.2 to 3.4, compression is raised marginally to 9.6:1, twin plugs and slightly hotter cams (Elgin Super C2). My understanding is that a properly running Carrera should operate with an oil temperature of 180-210 F under normal street driving conditions. My goal is to stay within that range after all mods. In the event that I'm above that operating range, I'd like to identify the best 1 or 2 options for bringing the temperature down.

Since I live in Southeast PA, my car doesn't tend to experience extreme heat - most summer days are under 95F. My car has the front Carrera wheel well cooler. The following maintenance/changes have been made to my oil cooling setup:

1. New external thermostat
2. Flushed Oil Lines
3. New Short Flexible Oil Lines
4. Oil Cooler ultrasonically cleaned by Pacific Oil Cooler
5. Oil Cooler boxed / shrouded
6. New oil cooler fan thermostat (turns on at 195F rather than
7. Oil Cooler Air Scoop

Please note I'd like to maintain my fog lights.

Assuming all components are operating correctly, what oil cooling mods would you recommend if oil temperatures are running at 220F and 230F? In addition to the types of mods I should consider, I'd also like to understand if the amount by which I'm over the ideal range (10F versus 20F in this case) affects the recommended solution.

Thanks guys SmileWavy

I've read here somewhere that Elephant's finned cooler lines really do help. This might be an option if your temps are mostly good but sometimes creep up above what's comfortable. If you're constantly way over temperature, then an additional cooler may be required.

Kev - I really like the idea of the finned oil line solution. My one concern is that 3.2 Carrera rockers mostly cover the oil lines which makes me wonder how much benefit they'll yield without removing the rockers. Do you know of any available data for this scenario?

Thanks! :D

Yeah, you're probably right, Andy. I suspect you won't get a huge benefit from the finned lines, though you may have nicely heated rockers. ;)

I don't recall any specific data on these. I just saw a post not that long ago about them, so that's why they popped into my head. I'd try a search as well to find most of the comments.

My one concern is that 3.2 Carrera rockers mostly cover the oil lines which makes me wonder how much benefit they'll yield without removing the rockers. Thanks!

I'm running that same set set-up sans cam.
Had a few days in the low 100s and the stop and go gets her a little warm. If you are cruising there will not be a problem with stock. I do not have the front scoop installed and havn't needed it. I think you will be fine with your stock set-up.

I hope you're right! My goal is to identify the next step in the event that the temps do run high.

You have 2 options
1) add a second valance mounted cooler, these are very efficient so you only need a small to mid size one. 5 1/2 X 2 1/4 X 20 would be on the large end and would cool the motor fine all by itself in street use.
2) add a second cooler in the drivers front wheel well, a mirror of the one in the passengers wheel well.

I use a second Carrera cooler on the driver's side (Bill V mentions above) and it works great, even on 100 degree days in race conditions. Without the second cooler (engine is a 3.5) my street temps were too high (did not even consider driving it on the track this way). Channeling and feeding air is also key. I see that you have the scoop and the cooler boxed in, but have you also notched the underside of the bumper?

If you decide to got the second cooler route, check out Elephant racing's tech article on the subject, as well as the prefabbed setup they offer. Pretty slick. Wish the stuff had been available when I did mine.

Good luck!

Andy, (polizei);

Your ’87 Carrera (930/xx) engine probably has its original 1.67:1 engine fan ratio.
Using a larger crankshaft pulley from some earlier 911s, you can raise the ratio to about 1.82:1.
Your Carrera crankcase has an up-dated engine mount, allowing even larger pulleys than possible on earlier cases.
This will help keep the heat producing parts (cylinders and heads) cooler.
In turn, this reduces the amount of heat required to be dissipated by the oil cooling system.
Consequently, the oil system will be regulated (~180ºF) by the thermostats rather than running ‘full-open’.

My other solution would be to ‘improve’ the oil cooling at the front.
In warm weather, I would wire the fan to be on all the time the engine is running.
I suspect there are more powerful fans available and coolers with greater heat dissipating capacity.

If you are going to track the car, consider the ‘Rubbermaid Solution’.
This simple, temporary mod almost negates the need for a front cooler.


An ‘outside-the-box’ idea might to be to ‘snake’ some ER finned pipes inside the front bumper, all the way across the front. Run the highest-temperature oil here.
(Perhaps in anticipation of adding a second cooler in the LF fender.)
Call ER and ask.

Best,
Grady

On my old 3.4 conversion in my previous '86 I ran with the stock Carrera cooler and it would run 225 on the street and 250-260 at the track. So I pulled my left front fog light and fabbed a NACA duct to catch the air and direct it to the cooler. Helped a little but only at track speeds. So for track use I pulled out the left headlight and cut a series of 2" holes it the back of the headlight bucket. Got me down to 225-230 on the track, still too hot but better than 260. But none of those things help on the street.

My BIL runs the Elephant second in the driver's side fender on his 3.6 conversion. Runs 200-220 on the limited street driving he does, but has to pull both headlights out to duct sufficient air to the coolers for the track

For your purposes, if this is purely a street car I think the cleanest and most effective change would be the second fender mounted Elephant cooler. Chuck's kit is very complete and fits well without a lot of hacking or fussing.

First off, my opinion is that you'll probably be ok with your setup with the added bumper notch if you don't already have one.
I was having somemhot iol issues with my new engine and felt like my situation was a little hotter than normal for a 930 engine(I had carrera cooler, scoop, no notch, fan and ER finned lines). I had replaced both oil thermostats, countless hours thinking about/worrying about my setup and situation. In the end, I added another cooler to the drivers side but feel it wasn't really needed with enough airflow to the passenger side cooler(I cut a hole in the valance).
So as long as you have enough airflow to these coolers, you would be ok with one, at least to start. I doubt you need the finned lines even though they're great and make changing out the oil more effective. Here is my thread in case you want to have a look.

http://forums.pelicanparts.com/porsche-911-technical-forum/692681-oil-cooling-air-cooled-cars-according-me.html

Guys - Thanks for the wealth of information. I'm going to wait and see how the temps look before doing anything! What exactly is meant by 'put a notch in the front bumper'? Any pics?

Here's the front of my '87 Carrera. Notice that there's an intentional gap between the bottom of the bumper and the top of the valance, which allows airflow from to the front A/C condenser blower and the front oil cooler:

http://forums.pelicanparts.com/uploa...1345566557.jpg

The notch would be above your passanger fog light. Not visable from this view, you would need to view from under the bumper. I'd bet yours has it, but if not, make one and make it big as you can.

101 projects describes it well.

This is the best and quickest solution for now. You do not know what the car is going to do but I suspect that the oil temps will be fine with no further mods.

Run a wire to the inside of the car connected to a switch, so that you can switch the fan on the oil cooler on at any time. That way if you get stuck in traffic you can turn the fan on long before it gets to the 210 or 240 degree position that the auto switch would turn it on, and thus keep temps down. Once you are moving IMHO I doubt that it would be needed.

If this works fine then you are done. If it works but still gets a bit warm, then as Grady suggested look for a better (or second) fan for the oil cooler. After these two things are done, and its still getting hotter than you like would I start changing oil lines, adding oil coolers and so on.

BTW, I have a 3.6 in my car and these engines do not have the "engine mounted oil cooler" like yours does, so its even more important with these. I put a nose mounted Setrab cooler on mine and plumbed it to work with the factory cooler in the RH front fender. Even on 116+ degree days out here in Arizona the temps never get above 225-230 degrees. If you get to that point, these coolers are great.

Yeah the fan deffinately helps when you don't have proper airflow and in town/traffic. Since I added the second cooler, and opened the valance for flow, I haven't used the fan at all. I live in vegas.
I watch the temp rise when at a stop light to maybe 195 for over a couple minutes slightly and when the light goes green it drops to 180-190 so fast it's just awesome.
http://forums.pelicanparts.com/uploa...1345572196.jpg

What I want to know is how did you get your car up on jack stands so close to the garage wall. SmileWavy

It's difficult to see from this picture but there actually about 1 ft clearance between the passenger side and the garage wall. This was enough for me to squeeze back there with a jack!

And he's good friends with Jenny Craig... :D