I have 93fd and just had my 13b built with new rotor housings and one new rotor. I live in Houston Texas where the temp normally rises to 90+. The guy who built the engine, reputable mechanic/tech on the race track and worked on race cars for 20+ years, put 20w50 in my engine and told me to keep this weight in my engine. Now I am not at a level of understanding where I can question his choice in 20w50. Does anyone use similar weight or have some input o this?

 

20w-50 is fine with high ambient temps IMO. Especially with typically higher operating temps of the FD and turbos. I typically run 15w-50 in the midwest summer.

If those using FRAM filters have good experiences I'd stick with them. Unfortunately my experience hasn't been that great. It's been a number of years, but my biggest complaint was gaskets sticking. Even though I always apply oil to the gaskets and only hand-tighten, they were always a bitch to remove. Note however that this was NOT on an RX7 (or a Honda).

 

The answer is use Castrol GTX 20W-50 and a Fram Filter.

Everytime.

No matter what.

Thats what goes in the FD. Thats what goes in the RX-8. Thats what goes in both Turbo FC's.

Thats what has gone in every rotary vehicle Ive ever owned.

No problem.

Ever.

End of thread / story.

 

Well, here we are again on flush or change intervals then...any 50 weight oil is going to be hard on the oiling system in winter. While it's undeniable that the higher weight will help in the Texas Summer to even flat out save an engine....and I have been there, limping a 12A home when the electric fan's old school fuse holder burned up completely and I had no way of getting air through the radiator but to drive on the shoulder of I-20 as I tried to get home during rush hour traffic....it is also undeniable that the lower weights will loosen up a bit of horsepower and that is solely through less friction in the oiling system. Car Craft ran dyno tests on a mouse motor to see if that was an Old Wive's Tale and they found out it was fact.

So, 20w-50, while it sounds all sexy, is also overkill and possibly harming the engine during winter. Just imagine all that resistance to being turned in the morning when you first crank it up on a cold winter day. When it cranks, the rotors and eccentric take over and force everything else to move at their speed right now. The oil pump, chains, etc, end up paying the price down the road since they are caught in the middle.

The least amount of weight you can use that will still float the bearings at idle and top end is all you need. For most cars, that's simply a 10w-30. I use half-synthetic simply because there was no denying that the Mobil1 5w-40 I had that day when the electric fan went out saved the engine..the needle was a 1/4" from topped out the whole drive home. The cohesiveness of the uniform structure of the oil's molecules maintained the sheer strength needed to keep that critical film of oil present on all the metal surfaces so I didn't lose my prized Rotary Performance Big Street port 12A on that massively hot Texas day. I simply don't think a pure dino oil is capable of that performance.

On a final note, I don't "Mobil" anything these days just like I never go to WalMart on a matter of principle.

 

Nah, Castrol 20W-50 is what to use all year long in every rotary car.

I live in Houston-ish. Its either warm or nuclear here.

 

...or there's a hurricane around the corner.

 

Ah, that's exactly what I DO. I hate Wal-mart, but I am happy to stop in before work (really early, before the crowds of fat slobs even roll over from their hangovers) and fill up on the Mobil1 5qt bottles at Wal-mart prices.

Otherwise, I agree completely.

David

 

^^ I use Wix filters. I've cut open both and they are very similar in media and design. K&N are nice on a vehicle with a downward facing filter, as you can wrench it off, which is a good idea. Rather than fight the oil dropping all over you. I agree with brand, as well. People that ask, I say just feed the beast and brand doesn't matter much.

 

The best oils use polyalphaolefins and/or esters in thier base stock. The primary use for these oils is in extreme environments such as professional racing, and they are generally a waste of money for regular street cars. Examples of top brands include Red Line, Idemitsu, Royal Purple, and Amsoil.

Most of the regular engine oil on the market will work just fine in your 94 FD, but you may want to avoid the cheapie off-brands as they could be made out of crummy Group I base stock and could have crummy additives. I prefer Castrol GTX in my RX-7s, and I usually use Valvoline Premium in my F150.

"W" stands for Winter, not weight (unless you are a Lucas Oil marketing guy who markets to ignorant rednecks). When you see a multi-grade oil viscosity index (VI), such as "20W-50", that means is that the oil has a 20 VI when cold, but a 50 VI when warm. For example, 10W-30 and 10W-40 have the same VI during cold cranking, but the 10W-40 has a higher VI when hot.

If you are concerned about cold cranking, then you want to look at the first number with the W, not the second number. For example, 5W-30 would make a better oil for cold weather than 10W-30. An oil rated for 20W-50 would be too thick for optimal cold-weather use, but it is because of the 20W VI as opposed to the 50 VI.

Ah yes, the old BDC method of reinventing the wheel by performing a test to prove what everybody in the industry has known for years.

Mobil 1 is no longer primarily made out of true synthetic base stock. Personally, I see no point in paying a premium price for oil that is just a little better than the cheap stuff.

If you don't understand the oil ratings then just go by the owner's manual or service manual recommendations.

 

I normally use Kendall but was at Kmart the other day and found Castrol for 2.49 a quart so bought 15 quarts of it. I already had 8 quarts of Kendall so I'm quickly becoming an oil shop...

Oil is badass, I love the smell of two stroke exhaust and anything but Gear Oil. Gear oil's smell is really bad and I swear I taste it when I smell it..