Honda D Series Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
1,789 Posts
Discussion Starter #1 (Edited)
I usually run acl race bearings in all my builds with 20w-50 valvoline race oil. Over the race weekend on Saturday my oil pressure dropped to 5-10psi hot, 40psi 4K and 70psi up to 8k. Pulled the main and rod bearings. They showed some overheating wear. Autozone had clevite oem replacement bearings. I threw those in there and was back up and running Sunday morning. Now my pressure is 35-40psi hot at idle and 90+ At all other rpm. Question is what other oil viscosities do you guys run on your turbo engines? I've never ran anything but 20w50 and race bearings. I am worried about how thinner oil will hold up under the stress and oil temps In the 240-280 deg range.
 

·
Classic Man
Civic
Joined
·
16,355 Posts
I would use something like a 0w50 or 10w60, something in that range if you have huge clearances and no oil cooling.

A 5w40 should do the trick, something that is approved for an OEM turbo car. Liquimoly, Castrol, etc.
 

·
Meat Popsicle
91 CRX Si
Joined
·
2,936 Posts
Is it just me, or do those pressures seem really low?
Compared to OEM, yes. But when you're running big clearances, that's how it goes...or maybe I've just been running too thin of an oil this whole time

With 5w-40 I see about 15 hot and 50 cold idle. That's with .0016" - .0018" main clearances.


OP, sounds like you need an oil cooler (or a bigger one if you already have one)
 

·
Registered
Prelude, Integra DB9
Joined
·
365 Posts
Please correct me if I'm wrong, but I thought Valvoline racing oil (VR-1) is a mineral oil. Don't temperatures over 260 need fully synthetic oils? And even then they'll be working hard.
Is your engine running really hot generally?
 

·
Registered
Joined
·
1,789 Posts
Discussion Starter #6

·
Registered
Joined
·
1,789 Posts
Discussion Starter #9
Any vids from any recent action, man?

I just keep hoping I dont see you on #racingfail :D
This weekend. And yeah I hope not as well
 

·
Registered
Joined
·
5 Posts
I have a low post count here, but I do have quite a lot of experience with engines.

The determining factors for oil weight should be bearing clearance, and horsepower levels, and less so, oil temperature.

Thinner oils always cool better than thicker oils, due to the fact that they generate less heat because they offer less parasitic drag in the crankcase, and also they flow better.

Also, full synthetic oils will keep their proper viscosity at high temperatures better than a mineral/dino oil will and additionally have less evaporation at high temperatures.

A high viscosity oil combined with a large bearing clearance will provide more of a "cushion" to high cylinder pressures. If you aren't making huge power 600-800 or more, I would not be concerned about that extra protection. Guys with 1200whp sfwd builds are using alum rods and 20w50 oil, nothing super exotic, but they are built for that purpose with the proper clearances.

I just built a d16/vitara turbo build with 0.0015-0.0018 clearances all across, started with comp 10w-30 break in oil and I had great oil pressure. 25 psi hot idle, and 70 at 3000 ramping up to 85-90psi at 4500 rpms My final oil is going to be Brad Penn Penn grade 1 10w-40 for street use, but my oil temps are around 195-200 on the highway and get up to about 215 with a few consecutive pulls. I'm just under 400whp

I would suggest a good synthetic in 10w-40 weight, and also consider oil cooling. Higher oil temps do make more power, but there's a limit. I would consider anything over 240 continuous to be too hot, and at that point you should look at auxiliary oil cooling. 280 is a bit hot, although not out of the protection range of a good synthetic. Also a synthetic will evaporate much less at high temperatures, less oil will go past piston rings, etc.

It's very possible that your overheated bearings could be due to a lack of proper oil flow at high rpm's, irreguardless of oil pressure. Remember pressure and flow are two different things, even though they are related. Imagine a 1/8" hole and pushing 75w-140 gear oil through at 90psi, verses a 1/8" hole pushing 5w-30 oil through at 90psi, or even at a lower pressure of 70psi. There will be a huge difference in flow.
 
1 - 10 of 10 Posts
Top