olddragger

iTrader: (3)

how far does your gauge go to?

Flashwing

If you have increased flow due to pressure has anyone considered OD is seeing higher temperatures because the oil isn't spending as much time in the cooler?

9krpmrx8

iTrader: (46)

It goes to 150PSI.

That is a good point. But it may be a good thing for me for now since I think my cooler is cooling a slightly little bit too much (160F average during normal driving).

madcows

It's possible, but I would rather have higher overall oil temps, than too much localized heat of the oil in the bearings. If it was truly a problem, then it wouldn't be wise for race engines to be running higher OP - but they do, so
As long as oil temps aren't critically high.

OD, it's only logical to assume that higher front bypass opening pressure will force more oil through the coolers - and if the rear isn't modded, then it should at least aid in better cooling of the oil. I will be looking forward to your future UOAs.

Flashwing

Again, you cannot compare race engine applications with street motors. Rotary engines that are raced do not use the stock oil cooler sizes. Also race motors do not see the kind of longevity that street cars do. Running higher oil pressures for 10,000 miles between rebuilds isn't the same as 100,000+ miles of street driving.

madcows

While I'll agree that what's good for a race engine isn't necessarily good for a street engine, I also think what's typically good for track engine longevity, is good for street engine longevity.

In this case, heat is probably being extracted from the bearings and rotor surfaces at an increased rate due to the additional flow. It's hard to imagine how this could be a bad thing. Overall, while the oil may be hotter than normal, it's still within spec. If a better cooling system is necessary, than so be it - it may be the necessary step in order to make the intended engine operation proper. At any rate, I would blame the increase in oil temp on the fact that the oil is absorbing more heat, rather than a deficiency of the cars cooling capability.

Flashwing

Race engines are not designed with longevity in mind in the same manner a street car's engine is designed. Race engines are designed to last the race. Anything after that is icing on the cake. Race engines are also torn down and rebuild every season or several times during a season. A street motor isn't intended to be rebuilt. It's intended to last the warranty period.

I'm sorry but no matter how you intend to justify it the two applications have totally different purposes. You cannot use race engine designs and applications and justify it on a street car. Otherwise we would be using race oil which has to be changed every 500 miles.

If the pressure increase has street applications then so be it. In my opinion the jury is still out.

The fact is, the majority of people on this board are not the Johnny Racecar Driver they think they are.

And where do you propose this energy is coming from? If there is a heat source in the bearings and rotor surfaces there are only two methods of that heat being removed. Oil and coolant. I have seen nothing mentioned by Denny saying he saw a decrease in his normal operational coolant temperatures.

Energy is neither created nor destroyed. If the oil is absorbing additional heat then something else is giving it up which would have to be the coolant.

At 120 PSI you're looking at nearly a 100% increase in pressure (assuming normal pressure is 70 psi previously). However, flow doesn't double as well but I'm willing to guess you're looking at a 25% to 50% increase in flow.

One of the reasons you don't remove thermostats in your coolant system is because the water will rush through the cooling system and not stay in the radiator long enough to do it's job. I'm willing to hypothesize that the increase in flow is preventing the oil from shedding it's heat as quickly. Oil gives up heat slowly and if it's rushed in and out it's not doing that.

If you see a reduction in coolant temperature AND an increase in oil temperature then I'd be willing to concede that the oil is absorbing a larger share of heat from the motor.

This is a bad method to use because, unlike coolant, oil's characteristics change with temperature increases and it's less capable of doing it's job.

ayrton012

Interesting thoughts from everyone.

Maybe the front bypass regulator shimming is enough if we have the original oil cooler system. The rear regulator fully opening pressure is about 92,5 PSI. We would get it if we mod only the front regulator. I will try it at my next oil change (soon).

Maybe the rear regulator mod (higher press than 92,5 PSI) claims to change the oil cooling system (coolers) to avoid much higher oil temps.

PhillipM

Not really, the mass flow through the cooler would be higher so it would be more efficient if anything.

longpath

iTrader: (1)

Does anyone have instrumentation on their particular RX-8 to measure temperatures after the oil coolers or in the pan (yes, I realize this is unlikely; but I won't know unless I ask)? If so, that person would be in a position to settle that question at least.

If the oil pan temperatures are the same or lower after performing this modification, or if there is an increase; but it is less than the increase on the hot side, then the increase in temperature on the hot side can not be due to a deficiency in oil cooler heat rejection brought on by more rapid oil flow.

olddragger

iTrader: (3)

lots of interesting thoughts--thanks all.

I need to mention something up front. MAZMART HAS NOT HAD AN OPPITUNITY TO DO ITS FULL EVALUATION OF THIS PRODUCT YET. Everyone please understand that.
These are my findings after my install. Mazmart is continuing to do a full and detailed evaluation of all aspects of this mod. They have years of experience in doing this type of modification on the previous rotory engines---just not the renasis. Some common things may appliy, some others may not. So patience my brothers, patience. So far imho it looks good.

That being said I understand what Flash is saying. I had a simalar thoughts concerning the coolers. I was also thinking the coolers maybe not having enough time to cool the oil in relation to before when the flow was less?
But further thinking I dont think thats it:
Some of my thoughts are:

1- I am not positive that the oil flow through the coolers has increased--it is lodgical that it has but I am not sure how the oil cooler bypass works. Is it temp related or pressure related?
2- my oil is warming faster from a cold start--coolers should not have any relation to that because flow to them is supposed to be very restricted when a cold start occurs?
3- oil temps are higher even with low rpms (less than 4K) so the pressures at the low rpms are almost the same as oem at a slightly higher rpm. IMO this means the oil is scrubbing more heat away from its designated areas.
4- oil and coolant to not cool the same areas. If you reduce your coolant temps the oil temps will go down slightly, but tax the oil system --like on a track w/e and your oil temps will rise even when your coolant temps are only slightly higher. For example--on the street on a 80F ambient day my coolant temps will be 180-185 in normal driving, my oil temps with the oem bypasses were always 170-175. Now this is driving with constant air flow.
On track with the same ambient--coolant temp 190-195F oil temps 205--210.
Higher rpms on track--higher adverage oil pressures. More heat is being generated of course and more heat the oil is scrubbing off. Yet coolant temps only very slightly higher.
Thats my thoughts at present.
Hard data still being collected.
olddragger

9krpmrx8

iTrader: (46)

My oil temp is measured after the cooler at the oil filter neck. Most would measure at this location with the use of a oil filter adapter plate.

ayrton012

It is temp related.
Maybe the too much flow or pressure blocking the oil coolers bypasses to open (actually closing) normally.
I don't know. I'm just thinking, but seems to me strange that higher flow means hotter oil.

9krpmrx8

iTrader: (46)

Is there a device that could go in line with my single cooler to somehow adjust oil pressure to fine tune it?

olddragger

iTrader: (3)

Lets stop thinking higher oil pressure?
Higher OIL FLOW has the capacity to remove more heat from the engine. More oil flowing over hot parts? Remember the bearings etc are probably 150F degrees hotter than the oil temp.
OD

9krpmrx8

iTrader: (46)

Yeah I agree, I am just thinking ahead in case my pressure is too high.

madcows

I remember reading a thread a little while back where Denny was suggesting that a decrease in coolant temps should also bring down oil temps. A few people argued this point, and now it's relevant here. If coolant temps in a rotary can hardly affect oil temp, then it's fair to say that heat extracted from the engine through the oil will not significantly affect coolant temp.

One last point, coolant and oil isn't the only way heat is extracted from an engine, while I can't say for certain, I would guess that most heat goes out the exhaust. So who knows, maybe OD's exhaust temps are slightly lower.

9krpmrx8

iTrader: (46)

Since installing my large single cooler I have not noticed any differences really in coolant temps even though my oil pressures are quite a bit higher.

Mazmart

iTrader: (12)

Don't worry. We can fix that for you .

Seriously though, let me know how your temps go if and when you use our product. I know you will be pleased as we haven't provided a product that was put together by Rick Engman (RE in RE-medy)that was not helpful on the street. We fully understand the differences and commonalities between the two.

Paul.

9krpmrx8

iTrader: (46)

As soon as I get it it's going in!! I have some other toys to install as well over the holidays.

olddragger

iTrader: (3)

doesnt take long--becareful with the oil pan bolts.

I am wondering also how/or if your oil temps will be affected. Since you have upgraded your cooler and cooler thermostat--it will be interesting.

Do this if you can---
time how long your oil takes to get to 110F after a cold start while your oem bypass's are in.
then do the same during a simular ambient temp day after the bypasss is installed.
I swear mine is warming faster and if more people can testify the same the more creditability the findings will have.

you have a 150 psi gauge and i will bet you are going to come close to pegging it even after warm up (using a 40W oil). Awaiting anxiously.

HiFlite999

iTrader: (2)

The problem with this line of reasoning is that the thermostat comes into play. With the RE-medy water pump and thermostat installed, I'm also seeing a max water temp of 170 deg and oil temp of 160. I would not expect to see much of a change after the pressure modification unless the driving situation is such that the thermostat is essentially fully open, otherwise any decrease in water temps will be regulated away. Then I'd expect to see a decrease in water temps after the mod (but who knows for sure at this point). It was 10 deg F (12 deg C) here last night, so I don't expect to temperature stress my cooling system for another 7 months.

9krpmrx8

iTrader: (46)

Okay I will time it tomorrow although I don't compare to stock because of the Fluidyne and Oil Thermostat but either way we will see. Then when I install the kit, I will time it again. And I am running Mobil1 0W-40.

Flashwing

Ok, I apologize as it had appeared that conclusions had already been made.

HiFlite999

iTrader: (2)

Just ordered! Hope I got in early enough to make it my Christmas holiday project.