Finally completed my 5 lug conversion. But why is my oil temp goes up faster than before. Is it because I have a lower diameter and wider tires? Or just a coincidence that after my 5 lug conversion there was another issue that makes my oil goes up faster than before. On the same weather condition around 65 degrees F, I used to drive my car for about 3 miles around city which my oil temp does not goes up immediately and I only get around 180 degrees but today I drove it and my temp went to 200.

Any experienced you have had or anyone can help me figure out?

Thanks again my fellow teeners and God Bless!

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Did you remove the deflector plates on the firewall underneath the car?

No sir! No other changes lately except the 4 to 5 lug wheels conversion.

Car looks cool! Who cares!



Why do those oil temps concern you?

Also could be several things......check the oil cooler make sure some garbage isn't in there of some obstructions.

Also check your thermostat cable.

My concern is, since I only drove it around 3 miles and my temp was already 200 plus, I was thinking I might be getting higher temp or can probably gets overheat if I drive it longer. My usual temp before wheel conversion with a longer period of time only around 220 max. I got the car last 2011 and I haven't installed or run it with thermostat here in SoCal.

Don't know about your temp but I'm an advocate for BBB's. That's Big Beautiful Bumpers. I like all 914's but I usually like what other people don't. Sweet ride.

The wheels look GREAT, Noel!!!!!!!!!

Good job!

Thanks "Old Yella" and Lawrence "Larmo63"! Yes for the looks it is better but for oil temp? Not happy with it! Maybe I will drive it tomorrow for a longer period and see what will happen on the temp.

Sir Lawrence, what tire size are you planning to use after you install your 5 lug conversion? Right now, it seems i have more space in between outside tire and fender lip. I think I may be able to fit 205x55 or 205x60.

I'm running 205/65 x 15 Yokohamas.

5 lug conversion and wheels Looks very nice.

Personally, I would swap the BBB's for early ones.

I do not see any possible correlation between the tire swap and oil temperatures going up.

Your car is lower and you have less air flow to turbulate under the car into the fan. If you are driving the same speed as before, your RPM's are now higher. The width of the tire will have negligible/nil effect on temp.

Nah Mike.......

The flaps are supposed to reduce turbulence and create dead air to avoid fan cavatation. He said they are there.

You didn't change anything else? So do you know for sure that the flaps are installed right or close in the full open position? You didn't leave a small rag somewhere by mistake?

Your engine is spinning significantly faster to go the same speed.
Stock tire diameter is 25.7"
185/65/15 is 24.5"
205/50/15 is 23.07"
The radius (half the diameter) of the tire is what is relevant. You went from 1/2" shorter than stock to a full 1.3" shorter. This is awesome when autocrossing. For daily street driving its kind of a drag buzzing along at freeway speeds and 3500 rpm. The owners manual shows that with stock tires @ 65 mph is about 2800rpm. Many of us go to the 16" rims so we can keep a low profile tire. You could use a taller tire like 205/60/15 to get that height back to 24.7" 200* is not a bad temp at all. Hopefully on a hot day you stay cool. Check tire rack for tire diameters. The diameters are all slightly different, but not to far off. Check out Tire Rack for exact specs on available tires.
Car looks great. I love BBB!

The flaps are a vortex generator to aid in air flow to the fan. Less ride height means less air flow.

With that said, it's still s stretch. tire changes should not effect the temp unless the rpm at a given speed is different

I respectfully disagree and will bet a beer on it when I see you WCR. I don't think that is the intention of the flaps. I'd never argue anything electrical with you though.....I know enough about that to be dangerous.

I think Kriegers explanation is more reasonable and don't think the oil temps are a problem unless it starts to spike. Head temps are more relevant anyway....but that's been argued here before.

You really should put a T stat in.

Flaps are there to create air flow up and through the engine. Somewhere here there's an engineering air flow study complete with charts and pretty pictures. Flaps create turbulence and cooling for the motor.

Try this.
http://www.cassidy-online.com/porsche914/a...2008_poster.pdf

* edit

Your'e right those are purty but....they look to be laminar air flow studies to design a an efficient wing for a 914. Interesting though.

I'm hoping to get schooled here without highj-acking the post.

In typical VW air cooled fashion, the engine compartment should be sealed by the cooling tin. The fan draws air from above the engine, pushes it through the cooling tins, and it exhausts below the sealed engine tins. If under car air flow is affecting the fan, you have got major cooling issues because under car air flow should not be available to the fan. This is how you keep the fan from circulating hot air during idle and creeping traffic…

"Cairo94507", Thanks for the comment and yes I might swap/change to early bumper which I have in stock.

Thanks Mike Bellis, Krieger, 914_teener, Colingreene and Bandjoey for all your comments/suggestions/concerns!

On the details below it seems lowering a tire diameter shows higher Revolution Per Mile. Is that one of the issue since it has 6.1% increase?

In regards to the flap, yes it is in there and no other changes made except maybe the car lowered a few inch that may limit air flow under the car and definitely no rags or any materials left in engine area.

I also have thermostat to be installed soon.
On my former tire 185x65x15 I do get around 3,000 rpm on 65 to 70mph speed.
Just to mention I'm using thermo dipstick and that is where I usually get my oil temp.

185/65-15 205/50-15 Difference
Diameter inches (mm) 24.47 (621.5) 23.07 (586) -1.4 (-35.5) -5.7%
Width inches (mm) 7.28 (185) 8.07 (205) 0.79 (20) 10.8%
Circum. inches (mm) 76.87 (1952.5) 72.48 (1840.97) -4.39 (-111.53) -5.7%
Sidewall Height inches (mm) 4.73 (120.25) 4.04 (102.5) -0.7 (-17.75) -14.8%
Revolutions per mile (km) 824.25 (512.16) 874.18 (543.19) 49.93 (31.03) 6.1%


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From what I have read, I think you are making much about nothing. Go drive the car! The fact it warms up faster is not an indicator of anything wrong. Check your thermostat and that the flaps are working, in your trans change you could have goobered up the thermostat or thermostat cable, knocked it off the pulley or jammed it. This would cause the flaps NOT to open, and could cause an overheat, but 200 is not a bad temp from what I understand. Go drive! As far as I am concerned getting up to operating temp FAST is a good thing. Just keep your eye on it so it doesn't overheat.

Yes, a change in hub/wheel diameter will increase your revs and higher revs would heat up the engine faster, but nothing to be alarmed about. Have you compared RPMs?

That minor change in tire size didn't change your oil temperature, but what's wrong with 200 degrees? That temperature is normal, even low. If it doesn't get hotter than that on a regular basis you won't evaporate condensation from the oil and it will turn to sludge.

The flaps under the car are there to create an area of lower pressure under the engine bay. That helps pull the cooling air out from around the engine, allowing more to be pushed in by the cooling fan, resulting in more air flow.

Note that your speedo (unless it's GPS-based) only counts revolutions of the wheel. So your RPMs at a particular speed shown on the speedo should not change when you change wheel/tire size.

I don't have a reason that changing out the suspension bits would affect the cooling of the car. Double-check the flaps, thermostat, and linkage as was already suggested. Also double-check the gauge and wiring as best you can.

I agree that 200F is not a concern. Drive some more and see if the temp stops going up there; if it does then you're fine. If it goes up past 220F then you're right to worry.

--DD

You're running at a higher RPM for the same speed due to the lower profile tire. You're probably shifting up because of it. I know this doesn't seem like it should make that difference, but if you had a cylinder head temperature gauge you would see that head temps go up dramatically when you are in 5th gear going up a hill. As these temps go up in the heads, the oils job is to haul away that excess temperature.
The solution is to keep the fan spinning.

downshift.

Andy! Well with everything except the BBB's. They suck ass...

Judo chop

Not if you're using the speedometer to tell your speed. The stock speedo only counts tire revolutions. Tire size can change until the cows come home and the speedo will give you the same reading for the same RPM in the same gear.

If you're using a GPS speedo, or judging by local traffic speed, that is a different matter.

--DD

Thanks again to all who commented or made some suggestions! Well I was not able to test drive the car for a longer period of time to see if I will really going to have more than 220 temp (which is my usual max temp when driving it longer and with the old tire). Just to mention again, I don't have thermostat since I drove the car 3 years ago. Well I have to finish wife car first today. Maybe tomorrow I will give some update again regarding my concern.

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Mike.......based on what Dave D says..........you owe me a beer.

Just an update. Well I drove the car for a longer time and yes the oil goes up quicker than before but the good thing is, it does not goes up to more than 220 just like before.

Thanks again to all and God bless!