HatsuneMikuOwO

I stumble across Quantitative Coolant Flow Simulation thread a few days ago. Been wondering if Mazmart water pump has less flow at the same rpm as stock but won't cavitate until 12k rpm(pump speed) and the stock pump has more flow but start cavitating at around 7730rpm and violent cavitation occurs at 9300 RPM.

Would it be more beneficial to underdrive OEM water pump to have the same flow rate as Mazmart? since OEM pump base on his result was superior up til 7730rpm(water pump speed) where it starts to cavitate and from what I can find users of Mazmart water pump shows no heating issue even with a lower flow rate.

on a side note, do series 2 use the same water pump as series 1? or have the same cavitating issue? I sold mine 2004 rx8 and had just bought a 2010 rx8 r3. it appears to have the same issue at high engine rpm (7~9k) where water temp skyrocket. especially during autoX, haven't have time to take the r3 to the track yet but my old series 1 had no issue being on track and somehow never saw temp over 205F even though OAT was at 70~75F. Might be higher speed on track help cool the radiator enough that cavitation doesn't matter?

HatsuneMikuOwO

How about this from Leg Motorsport in Japan? I'm currently saving up on one.

Gr8White

I intend to mod so I guess it's a S1 for me. This will be more of a project car than a daily driver but any mods will still err on the side of caution in terms of reliability; no crazy 500hp attempts. At least for now. I may eventually try for a 20b swap but I've got a lot more reading up to do on potential engines to swap in before I go down that road. Regardless it's rotary or nothing.

EDIT: Pls don't flame me for the 20b comment. I know they are stupid expensive to put in, a pain, and it's nothing I'm looking at doing any time in the near future.

Okki-Jakarta

Hey thanks, i changed all wires to the ballast too. it's all 1 set, ballast and wires, but im still using the oem bulb as it's so much better than the aftermarket bulb.

besides wires, will the shroud melt? that's my main concern

gwilliams6

This is the NO FLAMING THREAD, no worries man. Cheers. I have often dreamed of a 20b swap and have seen a couple, but yes more cost than buying a new car.

UnknownJinX

Can't buy a new car with a 20B in it, though, so it might just be worth it for some.

IamFodi

iTrader: (1)

Bump!

lotus retrofit

[QUOTE=Brettus;3793267]Here is your chance to ask a question that has probably been answered many times before or you might be afraid to ask because you don't know much about cars

No flaming please - just quick honest answers[/QUOTE

HatsuneMikuOwO

This is all I could find, this is rx7 fc turbo II oil flow diagram. I would imagine it's about the same? If so the flow will be:

Sump -> Oil Pump -> L & R cooler -> Oil filter -> Engine bearings and rotor -> Sump

Nisaja

Guys I have a dumb question. My buddy just bought a dead RX8 with a k&n typhoon air intake and he kindly offered to give it to me for free. I know I won't get any extra power, but I love the sound it makes.

Question is, is it harmful to the engine? I've been hearing that it sucks in a lot of dust and sometimes water when it's raining hard. On top of that, my friend thinks that's what killed the car he bought (the intake sucking in dust). Is that possible?

UnknownJinX

Some people say they are fine, some people say they kill engines, it's all over the place.

They don't filter nearly as well as the OEM air filter, that's for sure. There are also reports of oil getting onto MAF as well.

Your call. Personally, I don't think some noise is worth all that risk.

IamFodi

iTrader: (1)

AFAIK, one problem with aftermarket intakes on any car is that they can sometimes make air flow and IATs line up with load and RPM in ways that the ECU isn't programmed to expect. It can be subtle enough that you won't notice any power or mpg loss, but the engine still notices and "compensates" by running rich, and that will accelerate wear over time. I have no idea if anything like that happens with the K&N Typhoon on the RX-8. But if it does happen, I can see it causing a problem -- though it'd take a long time to notice the effect.

Same with dirt ingestion. It'll definitely accelerate wear, though it'll take a bunch of miles for the problem to add up.

The main problem with a K&N filter is that when it's time to clean and re-oil it, you have to do it PERFECTLY. If you don't, you get oil in the intake, too much dirt ingress, or both (usually both). And of course it's extremely difficult to do perfectly, so you can pretty much just assume it becomes a poor filter as soon as it needs to be cleaned.

And the main problem with the Typhoon in particular is that it hurts your ears above 5k-6k. I mean "hurts your ears" literally. At high RPMs it is loud enough to cause pain, and measurable hearing damage if you're exposed to it too much. I've experienced the pain myself and I've seen people talk about tinnitus after a track day. It's awful.

IamFodi

iTrader: (1)

Thanks.

This makes me think the filter would be in a different part of the circuit for S1 vs. S2, given that it was relocated for S2. Does that make sense?

HatsuneMikuOwO

I'm not sure since oil after the oil cooler has to go through a long hose to get to the filter, the same hose can be used to route filtered oil to the back of the engine and if was indeed changed from s1 to s2, where will the filter in the loop?

IMO if it's before the oil cooler, oil filter has to be near or on top of the oil pan and the oil pressure control valve has to be moved, it would also have a side effect of lowering the effective cooling capability because oil pressure control valve will dump excess oil back to the sump before it has the chance to cool and get bypassed before oil filter.

Steve Dallas

The Typhoon does nothing good on the RX-8, other than make noise, assuming that's good. My main complaints with it are:


1. It often causes rough idle
2. It messes with fuel trims in many conditions, making the engine run too rich or too lean at times

3. It does not filter well


Zeroing in on that last point... I have a K&N Typhoon on my track toy Miata. The level of silicon (sand) found in my used oil reports jumped from 4 to 28 from one report to the next upon installing it. How much sand is too much sand? IDK, but Blackstone lists 10 as the universal average.


If you want some extra noise, disconnect your VFAD actuator, so the duct stays open all the time.

UnknownJinX

On an S2, the oil filter is just about left to the rotor 1 leading spark plug if you are looking at the spark plugs from the driver side front wheel well. It's actually pretty close to the oil pan.

Whether this changes anything, I don't know. It's hard enough to find RENESIS I oil flow diagram, and the S2 Service Manual doesn't mention the oil flow from what I have looked.

Nisaja

Thanks a lot. You're right. Its not worth the risk.

Thats an amazing explanation. Thank you! I kind of agree on the hurting ears bit. I drove a car with the same air intake and the cabin got so loud after 6000rpm. It was as if an exhaust tip was inside the cabin! Crazy! Still sounded pretty good from the outside though. Oh well. It's not worth risking.

Thanks Steve! I think the k&n drop in filter is the same. A friend of mine had one and his MAF would always be covered in dust mixed with oil. It was disgusting.

I am interested in disconnecting the VFAD. Didn't know it was possible. Wouldn't it mess something up? How loud would it get? I did a quick search on here and found that it could decrease engine response?

Steve Dallas

I should have mentioned there are 2 reasons it messes with idle and fuel trims. You mentioned one, which is coating the MAF in gunk. The other is turbulence introduced in the intake airflow, to which the RX-8 is very sensitive.


I have had my VFAD deactivated since probably 2013 with no ill effects. It wouldn't call it loud, but it does make noticeably more noise.


Also remember that no intake provides any performance gains over the stock airbox with a clean filter. It IS a cold air intake, and it flows more than any N/A Renesis needs.

UnknownJinX

I mean, if you use any aftermarket CAI, the VFAD becomes useless.

Just cap the hose and you will be fine.

DartzIRL

All through reading this I wondered if electrive drive on the pump'd be doable. But the energy requirements and current would not be small. 400 amps at battery voltage or something, at maximum RPM.



The advantage of decoupling coolant flow from RPM would be interesating, especially on track - or even idling in traffic.



Then I found this thing:
https://www.demon-tweeks.co.uk/motor...ntroller-combo


Although, too broke to even attempt it, the idea looks intriguing.

IamFodi

iTrader: (1)

I'd imagine the reduced cavitation of the Mazmart pump has to do with the design of the impeller. To the extent that that's true, underdriving the stock pump wouldn't have the same effect.

Ultimately, "superior" shouldn't just be about one aspect, be it flow rate or resistance to cavitation. It should be about the net effect, i.e. temp management. So, the question would be whether the Mazmart water pump manages temps better at those RPMs. I doubt it, but I guess it's possible.

BTW, those simulations were done with pure water. Is that what you're running, or are you running a coolant mix?


Not the same pump. Don't know if it has the same issue.


I recently had my R3 out for a fast drive on a 96º day. I'm using 50/50 FL-22. Besides the water pump and coolant, everything in my cooling system is original with 89k miles on it. My coolant temps got into the 205º - 220º range but only on long uphill sections when I was really hammering it. Temps dropped fast once the road leveled off.

At lower ambient temps, I think you'll be fine unless something's wrong with your car.

The S2 has a comprehensively upgraded cooling system, so it seems safe to assume it'll do everything your S1 did, and more.

Steve Dallas

If my engine was not still under warranty, I would have already experimented with that setup.


It looks like there are three possible modes of operation:


1. Dumb mode: leave the thermostat in place and wire the pump to turn on with the ignition with no controller. In this mode, it would run at full speed constantly, and the thermostat and fans would function as normal. This mode should solve the high speed cavitation problem with the stock water pump, while otherwise keeping the car cooler across the board, assuming the thermostat is a good enough regulator on its own. Afterflow mode would be lost, as there would be no way to keep the pump running after shutdown, short of using something like a turbo timer, and that seems like a very cool (pun intended) feature.



2. Smart-er mode: remove the thermostat and install their controller. The RX-8 fan setup is a bit complicated, so I would probably start off trying to have the controller control the pump flow only, and leave fan control to the ECU. It would be interesting to see how well this might work (or not). If the pump is as efficient as they claim, the fans may never come on, except for when the AC is on.



3. Smart-est mode: same as number 2, but hack the fan turn-on relay(s) to use the signal from the controller. There are a lot of ways to approach this, since the 8 has 2 fans capable of running at least 2 speeds each.


Another thought... It looks like you could get by with the EWP115 to save some space and weight. If you double the Renesis displacement to 2.6L, you are well under the 3.5L rating of that pump.


And another random thought... What happens if something fails? Piston engines are pretty tolerant of overheating. Rotary engines are... not.


How difficult is it to remove the Renesis water pump impeller?


.

HatsuneMikuOwO

I'm still kinda confused what you said, as flow rate in this application doesn't seem to matter (Mazmart water pump w/ lower flow rate) and more about resistance to cavitation. and by lowering OEM's rmp to below 9300 it will reduce or eliminate violent cavitation and lower flow rate. posts of users of Mazmart water pump claim better high rmp temp and no more overheating issue, most of them also changed their coolant at the same time which is the reason I asked underdriver vs mazmart.

while on the topic of cavitation, will switching to evans eliminate cavitation issue?


On the subject of electric water pump. There was a post about converting 8's water pump to electric and there're electric water pump adapter for 8, but is it worth the risk when the pump or alternator fails? on top of that most automotive electric water pump are rated from 20 to 60 gpm but even the lower flow rate mazmart water pump is capable of 91 gpm at redline, will this be able to handle the heat?

IamFodi

iTrader: (1)

We seem to agree on the main point, i.e. what matters in the end is coolant temp. That's what I was saying. Flow rates and cavitation are interesting, but in the end, all we care about is whether coolant temp is where it should be.

If people have run the Mazmart pump back-to-back with the stock S2 pump, using the same coolant mix, with no other changes, and got lower temps with the Mazmart pump, then that would tell you all you need to know. I don't think that'd happen, but it'd be pretty definitive if it did.

However, it would not mean underdriving the stock pump would give the same results. We're still talking about different pump designs, so you'd have to test it.

I really don't think cavitation is an issue. Again, the simulations you linked were run with pure water, which would cavitate more readily than a 50/50 mix. Would Mazda really run a water pump that cavitates on 50/50 so badly that it can't manage coolant temps close to the stock redline? Do we really think they're that stupid? And even if the S1 pump had that issue, do we really think they'd fail to fix it when they redesigned the pump for the S2? If they did fail, how likely is it that a third party without Mazda's knowledge and resources would solve that problem without any downsides? Too many layers of improbability.

Regarding flow rate: It doesn't only affect overall coolant temps. It's also necessary to keep the exhaust side of the engine from being too much hotter than the intake side. I'd want to be very, very careful about messing with that.


It might. But like all waterless coolants, Evans is less efficient and has been known to raise coolant temps in a lot of applications. Again, the net effect is what matters -- not one aspect.


Well you still have the battery in that case. Hopefully. If the alternator fails, you get a warning light on the dash but the car keeps running for a bit and you can pull over.


Good call. If I were looking at numbers like that, I would read no further.

Hurrican111

This one cracked me up! My hairdresser baby is seriously injured though right now after the endless winter. I have managed over flooding and and electric malfunctions and carry OBD2 in my pocket and liter of oil in the trunk everywhere I go. But after having this 2006 Sparkie for over 2 years now I have to admit I am getting bit exhausted... rust coming out. And constant engine lights like it's Christmas every day. I had Pontiac Firebird 1997 before this one and even in high maintenance it never gave me such grief just kept going no matter what. Having the Cat on is definitely not so cool as it puts the car down in performance. I might be having it working on its full force too much but hey, that is why I bought it! So my stupid double question is...who do I have to shake to get spare parts spark plugs into this kiddo without costing my arms and legs at the same time. And why am I recommended to use NGK Laser Iridium plugs on internet site when it is not the original plugs...do they even fit?? I am fed up with mechanics here in Iceland ripping me off because I have not the standard Yaris crap everyone else is buying so I want to do this on my own but right now I am just simply confused.