Reccomendation for motor oil

[Mazda Carnage]

Originally Posted by maffatato15

well what would people think if i used that quaker state horrsepower full synthetic oil that just came out? Do you guys think my motor would be fine?


Right now i have castorl gtx 5w 30 in it

5W 30 is to thin for the summer.
I have run, Lucas, Red-Line, Royal Purple and ELF performance synthetic oils ( Elf is a European synthetic, supposed to be higher grade then North American synthetics), Castrol syntec, Valveline synthetic, Pennzoil synthetic and Mobil1 synthetic in 5w/30 10w/30 and 10w/40.

Synthetic does lubricate and resist break down better then conventional oils but the service intervals are no longer (usually 3000 miles/5000 KM) for both synthetic and conventional.

Besides break-down and heat there is one other thing that will cause a need for an oil change, Gas, these cars are old and the GT's run very rich, gas does get passed the pistons and contaminates the oil.

My personal experience, it's not as much the type of motor oil (synth. conveti.) but the viscosity that decides how well it holds up to turning black and deterioration.
I change my oil when it turns black and smells of gas, with synthetics (10w 30's) in the summer months I was changing my oil about every weekend (300-350 hard spooled KM's) (I only run 94 octane and add 2 litters of 120 octane racing fuel on the weekends for the track) when I moved to 10w 40 (even conventional oil) lasted about 2000 km's before turning black, this year 20w 50 and its over 3000 km before it starts to turn dark.

I am happiest with Castol GTX 10w 40 and 20w 50 conventional oil, since I don't go the full millage between changes I stopped using synthetics in stock engines (to expensive).


Chad (Zomiepapa) you might want to consider at least 10w 40 or even 10w 30 motor oil in the winter, at 23-20 below zero 20w 50 is like molasses and to thick to circulate properly on cold starts, starving your barrings... t'ill the oil warms up.


Apparently most oil filters are efficient only to 40 microns, an oil filter that filters to 30 microns will reduce engine wear by 50%. Now to figure out witch filters do.

[maffatato15]

Originally Posted by Mazda Carnage

I am happiest with Castol GTX 10w 40 and 20w 50 conventional oil, since I don't go the full millage between changes I stopped using synthetics in stock engines (to expensive)

so you think castrol gtx 10w 40 would be good for me then?

[Mazda Carnage]

Castrol GTX is a personal preference but a thicker oil is required here. If your heavy on the turbo when you drive and like to push the car, I recommend 20w 50, if your easy enough and drive the speed limits then 10w 40 is good. Synthetic or Conventional and brand is your choice, just keep an eye on the oil, with the 5w/ 30 your running watch your millage and note when it starts to turn dark, then if you choose 10-40 or 20-50 then check the millage again, you will be supprised with the difference.
Make sure you run GT oil filters, they have an oil pressure bypass thing ? (tired, can't remember the name) if the filter clogs the oil gets passed anyway (safety feature).

[GotF2TinGD]

yep i use the same as jon, super s 10w 40 mobil

use a good filter too, the smaller filter the better

[SinCity]

Wait, I always thought larger oil filters were better? I run Mobil 1 10W30 and Mazda oil filters with 5,000 mile change intervals. Most of my miles are easy highway (about 2,000 a month ) or I'd change at 3,000.

[fredio54]

Originally Posted by GotF2TinGD

use a good filter too, the smaller filter the better

wtf are you on about son??

Wait, I always thought larger oil filters were better?

dont worry, they are for a large number of reasons...

fred.

[zomiepapa]

Hey Danny ya i run 10 30 in the winter. I just put in the racing 20-50 in the summer. Runs like a champ. I should ahve my car on the road soon so i'll let you know about my white car.


Chad

[zomiepapa]

And just so you guys know just from someone who runs Super high performance cars every weekend. My uncle runs 6 second pro mods running 60 psi. He goes through engines every 2 race or race. He never uses Synthetic. Even in his daily driven Duster it dosn't make that big of a difference. Go with a good quality conventional and you will be fine.

Chad

[Keeloh]

so 20w 50 should do it on the summer even if its turbo? i used Moly Mos2 Antifriction Super Motor Oil 10w-40 all year long

[zomiepapa]

ya man 20-50 is gonna offer the best protection in the hear. Like Carnage said run it in hot weather no winter. use something thiner since the temperatures are much lower.

Chad

[91turbo666]

20-50 is probably too much, unless youre living somewhere very hot and very dusty. even the 10w-40 or 15w-40 that i use is more than what my manual suggests i use. plus you cant compare a dragster with a road car. an engine thats replaced every 2nd race doesnt have too much useful info about longevity does it, although i happen to agree conventional oil is fine. after all thats what mazda knew everyone would be putting in their cars 15- 20 years ago

[1989 mx6]

i have 222,000 miles on my mx6 and since mobil 5000 has came out thats all ive used and i dont burn a drop of oil. i only run it to 2500 miles then change it.

[zomiepapa]

no 20-50 isn't too much. Its just a thicker viscocity. Esspecially with the high milage it helps tremendously. but ya i shoudn't have compared my uncles dragster don't know what i was thinking. 20-50 is better, esspecially since most people on these forums don't put put around town... then use there mazda's for what they were made for...speed. Carnage knows best read what he posted lays it down and tells what you need to know. oil that is too thin does not provide optimal protectionm which are the bare essentials. Anyway i'm off
Chad

[my89gt]

i always use 10-40 all year long and i also add in the oil supplement, that thick stuff and my car has always run good with very minimal leakage.-
i am going to try that 20-50 tho, will be doing that this weekend, let u know if i feel a differenct or if i like it,,

[fredio54]

given that i typed it out, i thought i may aswell post it here...

(13:30:54) ANON : smaller filter better
(13:31:15) ANON : there was a big debate over it in the XXXXXX section a few yrs ago
(18:37:41) Fred: nope, the bigger it is, the less pressure differential across it. the less pressure differential, the less force to push those bits through holes that are marginal. the less blocked it stays, the less the bypass opens, and the less crap goes through there.
(18:37:55) Fred: the only way you could argue small is better
(18:38:18) Fred: is if you say that after a while the [shizzle] blocks the holes enough that smaller bits start getting caught.
(18:38:37) Fred: however by that time, the bypass is opening, and all the [shizzle] is just going straight through...


and then :

(02:52:32) ANON : smaller is better
(02:52:36) ANON : more oil stays in the sump
(02:52:43) ANON : less sitting in the filter
(03:34:27) Fred: you are supposed to fill it with oil, run the engine, and then top up to the high mark while the filter is full. most filters have an antidrainback valve also, so that all that oil stays in the filter until the rubber goes hard and the valve ceases to function..
(03:34:53) Fred: so, with proper procedure, and equal quality filters, the same amount will sit in the sump
(03:35:02) Fred: and with cheap filters more will be in the sump
(03:35:22) Fred: only if you have cheap filters do you have a disadvantage of longer dry periods at startup while its filled up

so there you go, thats my thoughts on why bigger is infact better.

fred.