20/50 Oil in an Evo? Partially Explained

[Jeffs2006EvoIX]

Hello folks, some of you that have read my posts in the past know that I have had a really hard time trying to understand which oil is "better" to be used in my 06 Lancer Evo 9. There are always many variables, but I have pieced together some reasons that engine builders of the 4G63 (engine used up to evo 9) recommend the use of a 50w oil vs the OEM recommendation of 10/30.

So here is what I have learned so far, and I would like some input from any engine builders here or just guys that REALLY know oil to see if these are valid points. Unfortuneatly I do not have any video or pictures of what I saw, just a description of what I saw and heard. Again, this is for my own personal knowledge.

My current oil is Redline 5/30 of which some of you know. I have been BASHED more than you will ever know for using this viscosity in my car and here are some reasons to why:

I just came back from a road trip to have my cars suspension receive a nice alignment from a well known and respected race chassis tuner. We got on the subject of oil for DD (in reference to Daily Driven) duties as well as race duty (meaning a closed curcuit timed event not street racing) and my friend that owns the shop threw in his 10 cents.

I stated I was suing Redline 5/30 oil in my car and when I said that the mechanic actually dropped his wrench on the floor and said "WHAT" and there it begins. I begun by stating about start up wear, about the POE based oil, the additive package, the HTHS and so on. EVERYONE IN THE GARAGE SHOOK THEIR HEAD. So I said, ok, what am I doing wrong and why?

My friend and tuner (engine builder as well for the 4G63) first started by showing me an engine that was recently pulled from an Evo running 10/30 oil. Though the internals where fine up top (valvetrain) and the crank look good and so did the pistons, the oil pump was not so fortunate. The oil pump had its teeth sheared off, and the crank had wobble in it. He went on to say that what happens with the 30w oils in the 4G63 is that in High RPM (6-7k plus) while under boost the 30w oil loses oil pressure, as this is happening, the oil pump takes the grunt of this that causes the gears in the oil pump to basically strip, ultimately causing engine failure.

As I thought this to be a fluke, I said ok, on a race motor I can see that, but not a "OEM Stock" block. He said WRONG!! THIS IS AN OEM STOCK BLOCK. OOOHHH I had nothing to say. This particular Evo was tuned, had bolt ons, and basically very similar in mods to my own car. So I started saying, about how is that possible? wouldn't a lighter oil be able to circulate quicker to prevent this? I was told no, not exactly. The oil is basically starved at high rmp while using a lighter viscosity.

The Chassis tuner who also races his own persoal Evo agreed and said he has seen allot of this. My mouth dropped. This is a very respectable person. I asked him what then? He said what happens like my friend stated is that oil pressure drops off significantly with a 30w, and though it is for use by Mitsubishi, he stated that was for MPG's not for durability reasons to why Mitsubishi chose that weight oil. Again, my mouth dropped.

So I asked the chassis tuner what he uses. His stock Evo. Brad Penn 20/50 his race Evo straight grade 40 or 50 Brad Penn.

I asked my Tuner what he uses. His personal Evo 20/50, his race Evo 20/50.

In the end I lost the conversation, the proof was right there. They both said, if I continue to use a 5/30 or a 10/30, you may not have a problem in the crank, or the valvetrain, or even the turbo, but your oil pump will fry sooner or later. Its up to you they said. Lose 4-5whp and some MPG's by useing the 20/50 and have engine durability, or use the 30w have a little more power and more MPG's but risk your motor in the long run. Wow.

So when I came home I did some more research on line and found this. I found TONS agreeing with this guy, but I will just use the one guy to save space.

question: What oil would be best used? a 30w?

answer: Too thin, as are most of the oils listed in this thread. There is a very specific reason you run 20-50 in a 4G63 and I have already mentioned it
Despite what some salesman might lead you to believe the 4whp you lose from thicker oils isnt worth a seized oil pump...which takes out the bottom end. Once it strips the timing gear then it slams valves, I have a car right here right now that went through this. Any Evo that is being used needs the thicker oil especially at higher rpm

question: so you recommend using 20-50 even when the car is stock from factory? I wonder why mitsubishi didn't think about that.

answer: I have a stock motor, I run 20-50 for the reasons listed above.

let me define my use of the word "used" in the phrase "any evo being used". If you run car over 7k and boost it at the same time then I recommend 20-50. But what do I know right?

question: but the oem specs shouldn't require a 50w right?

answer:
Piston to wall- 0.0025 (stock) .006 on a built motor
Thrust- 0.0015
Bearings- 0.002-0.0024

15-50 will work as well. I have used 15-50 before in various turbo engines, 5-50, 20-50, but the main thing is having the thick component weight to the oil. I use 20-50 valvoline in my stock motor thats in the car right now.

question: so whats the deal?? too much power for a 30w on an OEM block? Turbo?

answer:
Its not power its RPM. Bearings and the oil pump shaft dont like RPM on thin oil. The only tolerance that changes in a built motor is the piston to wall and that has very little to do with the cause of the failures I am describing.

Ask Curt Brown about his oil pump shaft There are very specific reasons I say what I do, I never say something that doesnt have multiple failures linked to a root cause then cured by something with direct evidence.

So basically that is what is happening. I have SEEN it, and now im very concerned about this. I was thinking of switching to Valvoline VR1 20/50 synthetic since I can get it anywhere in town and its affordable. Did I do wrong by buying the Redline 5/30?

Oil Gurus, Your opinion? Out of curiousity if anything. Thanks for your time in reading, and your experience.

Jeff

 

[dtt004]

Hi.

I am an automotive engineer and deal primarily with the motorsports arm. Remember, a higher viscosity oil will always provide greater film strength at higher temperatures than a lower viscosity oil. This is chemistry and physics. However, I have trouble believing that the OEM-specified oil is the cause of oil pump destruction...and not the driving habits.

Race tuning shops have their business and gradually build their name up as they tune vehicles. They are outstanding at it. But that's what they do. They tune what's already been developed. Thousands of hours were invested by Mitsubishi to make sure that this car was designed within specifications. We specify certain things for certain reasons. For example, the move to XW-20 oils was chiefly done for fuel economy, after evaluation of the most common driving habits and corresponding engine wear trends. This oil was deemed as protective enough to last through the usable life of the engine. This usually means to the end of warranty. Also, legally, if you race the car/engine...you are out of our hearts and minds. It is not the engineers' responsibility to create a consumer car...for the stresses of motorsports usage. We have different engineers doing that. And...the engines are rebuilt after each race. That is the typical life of a race engine. It's got fresh parts each time.

I wouldn't say the engineers were 100% correct (nobody can be) to cover all variables when specifying an engine oil. They do it to cover 90% of the people on the road with that car.

--> A higher viscosity oil will introduce higher oil pump pressures.
--> You must ask if there were any failures using that kind of viscosity.
--> Oil is oil. It is a fluid. A fluid has limits. How can it withstand the thousands of pounds of pressure and strain introduced in combustion?
--> Racing oils are for racing. I would not recommend their usage for consumer use. There are different variables involved.

I do not necessarily think that you made a wrong choice in viscosity. However, because you race the vehicle, you will experience a lower product life. The car will not last as long as one that is not raced. It's simple.

I strongly recommend that you buy one car for street use and one car for racing use. Then you will not have to worry. However, I understand this is not financially feasible for many reasons...

But it's not the oil's fault. Seriously. I believe it is the driving habits and conditions. It's easy to blame an oil's viscosity than to blame driving habits.

Remember, there is only so much an oil can do.

Also, the 4G63T is an aged engine. It was not designed for high RPM performance. The proof is in the stroke, the cylinder head design, and the hydraulic lifters. The newer 4B11T was more specifically designed to achieve higher RPM power. However, it was saddled when they placed it inside the Evolution X's heavy heavy heavy chassis. Think about it; if they put the 4B11T inside the Evolution 8/9...it would be a much faster car than when outfitted with the 4G63T. However, the 4B11T also has a poor-flowing cylinder head. It needs to be modified to achieve better airflow at higher engine speeds.

So yes, I think it is a combination of factors leading to oil pump failure. The oil pump is only one part of the puzzle, and...if you look at it...it's a very fragile part.

On a side note, I am not meaning to douse the business of Brad Penn, but we have analyzed their oils after testing in our racing engines here at work. We have tested 3 grades: 10W-30, 10W-40, and 20W-50. After reviewing the test results, I have no clue how it can be better than Redline...or any other manufacturer's oils. They are so similar. They all get destroyed when running an engine during endurance testing.

 

[Jeffs2006EvoIX]

Thank You for your response and being an engineer puts a nice prospective on things. I agree with you that I don't think its some kind of design flaw, but rather when cars are pushed to their limits they "find" the flaws. I beleive that is why R&D in racing is so important for manufacturers.

I do not "race" my car per say. I do run SCCA solo 2 events in a modified street class a couple times a year. That is all. What has been found is this. Stock boost on the 4G63 is 22psi which drops to around 16psi at WOT by redline, on tuned cars you see a spike at 26-27 psi then drop to 22psi at redline at WOT. The increase of boost and high rpm causes the oil pump to fail (in theory) this has been proven. There has been no reported failures while using a 20/50 oil. They didn't specify race oil, just to use a 20/50. I just wanted to use VR1 synthetic since its readidly available and is fairly priced.

Am I at WOT often? No. But as an owner of a car like this, I tend to have fun in the car, and when I do pass cars, I don't take my time if you know what I mean, haha. Its like the saying goes, "an ounce of prevention is worth a pound of cure" so if using a thicker viscosity "could" eliminate a "possible" failure wouldn't that be the route to go? Here in Southern California where I live, I don't think using a 20/50 synthetic year round would cause any harm.

I am considering though to just switch from 5/30 redline and go with a 5/40 from redline instead. It has the same HTHS as a conventional 20/50, so that is an option for me.

The 4G63 is an aged engine, very true, though, it has been in racing for over 20 yrs and every year got better and better. In the end of its cycle it made more hp per liter than any other mass produced engine in the world. That says allot to the ability and drive of the Engineers at Mitsubishi.

So would using the 20/50 oil cause any harm in other areas I guess is my question. The engine builders say No. But then again they are not oil specialitst. haha.

Im not running to the store to change my oil, I just have 1000 miles on my 5/30 Redline, its just my "next" oil change may be with a different viscosity. I just would like as much input on this as possible. The Aftermarket Engine builders have seen the failures and found a way to correct things. Not just the oil, but parts that get replaced and upgraded throughout the engine. I am sure Mitsubishi could make the engine even better but have limitations of cost and the EPA.

so it seems that the lower viscosity (30w) makes oil pressure drop at high rpm, which could cause an oil pump failure, where as the thicker viscosity (50w) maintains a consistant oil pressure throughout the entire rpm band resulting in better protction to critical parts during high rpm or under boost.

Its a tough pill to swallow. The 20/50 oil goes against everything I have read about, talked about on these forums and elswhere. Its not that I can't make a decision, I just want to make a good one.

Any other input would be much appreciated.

Jeff

 

[Rohan]

I think 5w30 redline will be good if is pushing more power from the factory.

I asked David can extra powers can handle 5w30, this is what he said:

The 5W30 provides very good film strength and protection, so would be suitable where additional power is produced.

Idk if is true or not.

 

[Doug Hillary]

Hi,
Jeff - Perhaps it would be more productive for you to read CATERHAM's Posts on HTHS viscosity

 

[A_Harman]

It sounds to me like the 4G63 engine has an issue with oil pump shaft lubrication when operating at high rpm. Maybe its bearings are being starved above 7000rpm? Is this common knowledge in the EVO community? It sounds like an oil pump shaft is seizing and causing the teeth on the gears to be stripped off. Is this how it looked on the pump that you saw?

It is curious that the torn-down engine they showed you did not have bearing or valvetrain damage. Apparently the rest of the engine was OK with the 10w30 oil, but not the oil pump. How could the oil pump gears have stripped, yet not have caused the crankshaft bearings to seize when the pump stopped? Does the engine have a low oil pressure shutdown to protect it? Or did the cam drive break, causing immediate shutdown, and a set of bent valves in the bargain?

dtt004 has a very good question when he asks if there have been similar failures when using Xw50 oil.

The tuners are advising using 50-weight oil because increasing viscosity is always cheap insurance to overcome a deficiency in the oil system, rather than fixing the root problem. I can't fault them for that; fixing such problems can be expensive.

I think it would be prudent to increase viscosity on your next oil change to get insurance against the oil pump problem. How high to go in viscosity? M1 15w50 has HTHS of 4.5. RL 5w40 has HTHS of 4.6. Brad Penn 20w50 has HTHS of 6.2. RL 15w50 has HTHS of 5.8. VR1 Syn 20w50 doesn't list HTHS. In the meantime, avoid extended operation above 7000 rpm with high oil temperature.

 

[SteveSRT8]

If it was my car, I'd be looking at the 15w-50 oil for it.

Boosted Evos run great until you approach that 25-30 psi range and then they tend to drop like flies. Every one I've seen has failed due to poor tuning, fuel mixture, etc., not oil starvation.

Keep the boost under 25 psi and run Amsoil Dominator 15w-50 and I bet you have a long and happy life. Most of those things run so strongly you can't keep your foot down very long!

 

[Jeffs2006EvoIX]

Harman you kinda are seeing what the problem was and sorry I wasn't so descriptive, was trying to keep the post kinda short anyway.

Yes, the teeth on the oil pump were sheared off, and the valvetrain was toast. Bent valves the whole shi-bang.

I have been emailing evo shops all over the country and seems everyone is kinda shy about the matter. I think no one wants the responsibility of saying, "yeah use this" then something happens and you go after them kinda thing.

The 4G63 does starve for oil at high rpm's there simply is not enough oil in the pan. Oil changes require 4.6 qts, but I always just throw in 5 to have that little extra in there without being too much extra.

So what they are telling me is the 30w oil just lowers the pressure too much where as the 50w maintains the pressure much better. My friend said to use it even in a bone stock 4G63 as cheap insurance.

I brought up the same point about HTHS values and didnt get a clear response on that. I am running Redline 5/30 now which has a HTHS of 3.8 vs the Mobil 1 I was using at 3.2

I was considering going to Redline 5/40, but was thinking of the 20/50 VR1 or 15/50 M1 since I can buy it anywhere and save some money to boot. M1 is not the popular kid on the block in the Evo world any longer. I think their reputation has been tarnished some since the whole hydro cracked oil implication.

I don't even think the M1 15/50 is as good as it used to be, so that is why I am thinking of just using the VR1 (synthetic).

So guys and gals what do you think on this subject? Seems like an HTHS issue to me, not really a viscosity itself per say.

Also note, its High RPM oil starvation and boost combined that really hurt the pump. I really think Mitsubishi felt that most of these cars were going to be raced or something and figured the ones that would be on the street and stayed stock were driven very conservitivly so the 10/30 M1 from the factory was sufficiant. This is all theory since I don't know any Mits Engineers.

Your talking a very limited production car, it was never really meant to be just a street car. I think Mits new this, as well as the people buying these Evo's.

This is a quote from my friend who builds these things: "I would rather you use 20/50 wal-mart super tech oil than 5/30 anything!" He was pretty adiment about it. Then was backed up by the chassis engineer that races Evo's himself.

I am still waiting for some replies from other well known 4G63 builders. This is something that just makes me want to go mmmmmmm.

Jeff

 

[Jeffs2006EvoIX]

quote:
If it was my car, I'd be looking at the 15w-50 oil for it.
Boosted Evos run great until you approach that 25-30 psi range and then they tend to drop like flies. Every one I've seen has failed due to poor tuning, fuel mixture, etc., not oil starvation.

Keep the boost under 25 psi and run Amsoil Dominator 15w-50 and I bet you have a long and happy life. Most of those things run so strongly you can't keep your foot down very long!

Tuning is the Key. Most people use manual boost controllers and self tune. Those are the ones that go "pop". I have been running 26-27psi (@WOT) for over 3 yrs. Its all in the tuning. Lucking for me, I have one of the best Evo tuners in the USA as a personal friend.

Boost doesn't kill the car, running lean does. I was running 30psi for a year with Meth/water Injection as well, and on E85 I run 30psi. Car is 5 yrs old knock on wood been solid.

So people are still liking the M1 15/50?

 

[unDummy]

Anyone monitoring oil temps or oil PSI with these so-called pump failures?
What happens when someone has a failure with 20w50?
What causes the 'oil pressure' from dropping off? temperature? aeration? poor oil control?

If its a lubrication failure, its caused by something. That something needs to be figured out. I doubt that 20w50 is a fix. But, it is definitely a bandaid for that something.

Sounds to me that the gears aren't strong enough. Maybe worth upgrading or looking into improvements.

 

[SteveSRT8]

Almost certainly poor oil control with aeration.

Pump is geared to push volume up top to all that valve gear, probably can't drizzle back down quick enough at high rpm.

There were many old school racers who overfilled their sumps to protect against this. I bet an extra quart (if no crank contact) would be cheap insurance.

 

[CATERHAM]

Originally Posted By: Jeffs2006EvoIX

I brought up the same point about HTHS values and didnt get a clear response on that. I am running Redline 5/30 now which has a HTHS of 3.8 vs the Mobil 1 I was using at 3.2

So guys and gals what do you think on this subject? Seems like an HTHS issue to me, not really a viscosity itself per say.

Very few otherwise knowledgeable tuners know what HTHS viscosity is so if you want to communicate effectively you should first understand it well yourself. The following post might help:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2001169&page=9

RL 5W-30 with it's HTHS viscosity of 3.8cP is better thought of as a robust 40wt oil. I say robust because it contains no VII's and is therefore impervious to shear. For example, you will have higher oil pressure with this oil than M1 0W-40 at all temperatures, that's how viscous RL 5W-30 is.

RL 5W-30 is effectively a grade heavier than the M1 10W-30 you were running and if you're familiar with the oil pressure reading in your car you should have noticed this.

One thing I haven't heard in this post from your tuner friend or others is what they recommend as the lowest oil pressure you should run at maximum rev's, because that really is the bottom line in how thick or thin the oil should be.
Since any 20W-50 oil is recommended, a typical 20W-50 dino has a HTHS vis' of 4.4cP to 4.6cP or so and that's before shearing. After shearing it's value can easily drop below 4.0cP which isn't far off R/L's 5W-30 which as I mentioned won't shear; viscosity loss due to fuel dilution perhaps but not oil shear.

Since your car is used just for fast road work with no track use; I don't consider autocrossing as track use, I think the RL 5W-30 you're running is just fine. But what you should find out is the recommended minimum oil pressures and and simply keep you foot out of it if your oil temps are getting high and therefore your OP is getting near this recommended minimum.

 

[dailydriver]

Originally Posted By: CATERHAM
Since your car is used just for fast road work with no track use; I don't consider autocrossing as track use, I think the RL 5W-30 you're running is just fine. But what you should find out is the recommended minimum oil pressures and and simply keep you foot out of it if your oil temps are getting high and therefore your OP is getting near this recommended minimum.


What HE said^^^.

When you were talking about "track use" previously, I took it to mean; Time Attack/Time Trials/Solo 1, open tracking, etc.

Most Solo 2 runs are soooo short in duration that your viscosities with the RL 5W-30 should not even be a factor/worry, unless you keep it in first gear the whole way in a 60+ mph on the straights autocross (and in reality NOT even then).
The turn-in lean angles (even in a less leaning ST/STS, or SM class suspension prepped car), and super quick direction changes would be the main oiling/oil starvation issues in an autocross scenario, but still no match for the challenge of L-O-N-G, extended, high speed, high g turns (at MUCH higher revs than in Solo2 events) which occur in a road course event.

I am most admittedly NO 4G63 expert, but if it were me, I would be questioning these builders and tuners about; Accusumps, baffled/trap doored sumps, windage trays, rebuilt/improved/re-engineered oil pumps, and running a quart over stock capacity.

Also, if you are worried, and are taking what these tuners/owners are saying to heart (I know I probably would be as well), you could try the Red Line 10W-40 next change.
It would be great in Cali year 'round, is thicker than the 5W-30 in ALL regards, and albeit slightly thinner than their 5W-40, it has more soluble moly than that grade (no SAPS to worry about, since it's not a 'diesel grade'), and NO ADDED VI improvers (as good and shear stable as the ones RL is using are, and as little as they actually add) like we know the 5W-40 does.

 

[unDummy]

Originally Posted By: dailydriver

I am most admittedly NO 4G63 expert, but if it were me, I would be questioning these builders and tuners about; Accusumps, baffled/trap doored sumps, windage trays, rebuilt/improved/re-engineered oil pumps, and running a quart over stock capacity

Too simple. Just say 20w50 and hope your reputation holds.
Add crankshaft scraper and external oil drain back lines. And, if there is a balance shaft, remove 'em!

I'd fear any MINERAL oil in a turbo engine. So, do we know what brand/type was being used with all the failures? JippyQuickeeLube serviced, 30wt mineral oils, 7500 oci, 10% fuel dilution???
I can't wait 'til the sludge monster 20w50 mineral oil failures rack up. Or, will the tuners hide them?

There is more to the failure then they're letting out, because they just don't know.

Redline is a great choice. If you're making more power, and/or engine is running hotter than normal, then go a little thicker. They also make a 0w40 and 5w40.

If a component if known to fail, or has repeat failures, that component needs to be looked at. REM/Cryo/Metalax/... treatments should be considered. Polishing/chamfering/deburring/clearancing...need to be studied.

 

[Jeffs2006EvoIX]

Thank You everyone for your input. This has been a very dificult thing for me to get more proof on. The oil that was used in several failures was M1 10/30 from what I am being told. My friend won't even carry M1 in his shop any more. He used to stock it, when I went in there this past weekend, none on the shelves. He had a variety of oils on the shelf, but No more M1. I asked about that too, and he said, Just don't want it anymore. Had bad experiences with it.

We can argue back and forth, and the fact that the oil "caused" the failure? I to find that hard to believe, but he saw something that freaked him out because he used to sell M1 at his shop. He is not an oil distributor for any brand. He just stocks what he likes.

I have never heard of Oil pumps failing on Evo's before. When I email numerous Evo Engine builders, no one responds. So soon as I get some reports back from them, then I can make an assessment to see if its a fluke, or its something happening often throughout the USA.

I have a feeling that a particular car in his shop blew an oil pump and he got scared. It happend to have 10/30 M1 in it. The thing that gets me though is the Chassis tuner that was there, that has no affiliation to the shop said the same thing and he tours the USA tuning chassis on Evo Race Cars. So I am not sure if this is something happening on Redline Time Attacks, when High RPM and such are for long periods of time or what. I just feel with my mods, and the oil I am using (RL 5/30) it should be more than adequate for what I use "my" car for.

I am sure I am will get Loads of slack from him, but honestly I am putting my faith in Redline. Prior to that I ran RP Racing 41 and prior to that M1 EP 10/30 and had no issues (knock on wood). Now the Redline 5/30. My gut feeling is that the RL I am using now is the most robust oil I have ever put in my car. Even more so than the RP Racing 41.

I was curious though why the RL 5/30 has the highest flashpoint of any RL Street Oil. You would think the thicker viscosities would have higher flashpoints, but the 5/30 has the highest. Anyone know why? I was thinking of just going to 10/30 RL next change, but the 5/30 seems to be the most robust 30w Redline offers (street oil).

Im sticking to my Redline 5/30, my gutt feeling is telling me too even after what I saw. Any more input would be much appreciated.

Jeff

 

[A_Harman]

I'm with dailydriver on the RL 10w40. It's a little more robust than the RL 5w40. Its lower ash content would be more appropriate for a highly boosted gasoline engine.

 

[rpn453]

Originally Posted By: unDummy
I'd fear any MINERAL oil in a turbo engine.


Even the 15W-40 diesel engine oils? Are turbo gas engines harder on oil than turbo-diesels?

 

[A_Harman]

Originally Posted By: rpn453
Originally Posted By: unDummy
I'd fear any MINERAL oil in a turbo engine.


Even the 15W-40 diesel engine oils? Are turbo gas engines harder on oil than turbo-diesels?


Yes. Diesel engines rarely get above 1250F on turbine inlet temperature. If they get to 1400F, the turbo becomes susceptible to bearing problems. Gasoline engines get to 1700F turbine inlet very easily, and can easily top 1800F if the mixture isn't tuned excessiveley rich.

 

[unDummy]

Originally Posted By: rpn453
Originally Posted By: unDummy
I'd fear any MINERAL oil in a turbo engine.


Even the 15W-40 diesel engine oils? Are turbo gas engines harder on oil than turbo-diesels?


My friends truck has a ~47 quart sump and redlines at 2200rpm. If its low on oil, he tops off in gallons.

THERE IS NO AND SHOULD NEVER BE A COMPARISON BETWEEN A DIESEL ENGINE AND A GASOLINE ENGINE, OR THEIR OILS.

And, I would NOT use a 15w40 mineral diesel oil in an overly hot turbo gasoline engine, especially one that is modified and pushing 300-700hp on a 4-quart sump.

 

[CATERHAM]

Originally Posted By: Jeffs2006EvoIX
Thank You everyone for your input. I am sure I am will get Loads of slack from him, but honestly I am putting my faith in Redline. I was thinking of just going to 10/30 RL next change, but the 5/30 seems to be the most robust 30w Redline offers (street oil).
Im sticking to my Redline 5/30, my gutt feeling is telling me too even after what I saw. Any more input would be much appreciated.
Jeff

To cut the "slack" from your tuner friend who is not familiar with RL or high HTHS vis oils, simply tell him you're running a 5W-40 which in effect you are.
Forget about RL's 10W-30, it's HTHS is no higher than the already VII free 5W-30; all your would be getting from this obsolete low VI grade is a thicker oil at start-up which is exactly what you don't want.

And finally, don't "put your faith in RL", instead educate yourself about the oil pressure characteristics of your engine. An OP gauge is the best proxy for how thick or thin your oil is at any given time. If you don't have a fully functional oil pressure gauge get one and an oil temp gauge would be useful as well for your modified engine.
Some questions you should be able to answer are:
What's the normal OP for your engine when up to temperature?
How much does it drop when driven hardest?
What is the bypass OP setting of your oil pump?
When autoXing, does the OP ever drop off or fluctuate?

Cheers