no vote necessary - it is written down on the internet so it must be true

 

hmmm - wonder what effect lowering the pump speed at high rpm (a la UD pulley) would have ???????

 

It would have the effect of bringing it to a near stop at idle when most people have their overheating issues.

 

could be an issue - if you live in Phoenix .

 

Especially in Phoenix (and Texas, New Mexico, Nevada and other places where the motors are being replaced on a regular basis).

 

Thats the point. You have the data. Why don't you share you overwhelming wealth of knowledge that you claim to have with us less acomplished folk? Where is the betterment of the community hoarding the data away?

Why do i have anything to prove? I'm not the one that made any statements about how things are. I asked a question. All I said was post up the data you have.

 

I did post it up by mentioning it. Its not like I sit there and graph temp data, smart ***. That data isn't particularly useful for power, though it is definitely something you become aware of the more you run cars on a dyno.
When I dyno tune, I put the engine into a load cell and tune for A/F.
The engine temps will load up more and more in each successive load range until you get to the torque peak, after which it begins to take longer for the coolant temps to rise.
Coolant temp rise roughly follows EGT.
How about you go and run your car on a dyno with a brake and chart the temps with a thermocouple? I'm sure you will find it amusing.

EDIT - You know, I think you may not be understanding what I am talking about, so let me clarify.

If you put a car on a load cell dyno, you will bring the motor up to a particular RPM and then load the drum so that the engine speed does not increase while the throttle is held open. After a second, the A/F will stabilize and you can make adjustments, noting the EGT. EGTs will be at their highest when torque is maximized, which means you are at the proper A/F for that load.
You can only do this for a few seconds at a time because it begins to load up the cooling system of the car.
EGTs will be at their total highest at the correct A/F at the torque peak of the motor. They drop off somewhat above and below that point.
What you also notice is that engine temps don't rise quite as quickly as you go above the torque peak load cell because VE is dropping and less combustion energy is being released per puff.
You cool down he car for 5 10 minutes between runs and start over in a new load cell.

 

The guys at Mazmart have done extensive dyno testing of the flow rates on this pump. Look at what they do for a living...ie build race engines for a lot of high end applications......don't think they are going to play around with something that won't work. Rick is way too picky for something that doesn't work for it to leave the shop.

If it was easy...they would have had it doe about a year ago when they started to play with the design

 

Don't get me wrong - I absolutely expect this thing to be the bee's knees.
We were just discussing the various scenarios.
Ultimately, a good, working mechanical pump in the OEM position is going to be the best solution because it is the simplest.

The only question that arises is why would Mazda spend money on development of a different pump design for this motor that is inferior to the REW pump?

 

Mazda didn't develop it as far as I know I know that they have a direct relationship with Mazda of some sort...but they aren't joined at the hip...as far as I know.

 

No, you misunderstood.
I want to know why Mazda spent money on developing the OE pump that comes on the Renesis.
It was a conscious decision on their part to change the design from the REW pump.
I want to know what the goal was. Obviously, it wasn't to save money.
Why do we find ourselves with a less-than-optimal pump?

 

I would think it is a combo of bean counters...and design to fit the space at hand. I'll have one of these to look at next week...and will see what they changed.

I can compare it to a 13B pump as well.....

 

Was the FD redline 9k? I never owned one.

I don't know if this was mentioned directly, but the reason why the temps build up fastest at the torque peak is basically because that should also be the volumetric efficiency peak of the engine. Thus it is taking in the most air and fuel per cycle. The coolant flow is roughly proportional to rpm. Thus, per RPM, you have a fixed amount of coolant brought in. Your torque peak is then also the peak in your ratio of gas burned to coolant feed. More combustion for a fixed amount of coolant is a greater flux of heat into the coolant.

There are subtle differences in the Renny and REW. Moving around the ports and removing all port overlap changes both the combustion chamber temps and coolant flow. It could be that the Renny water pump is similar in performance to the REW, but that the coolant flow is less ideal. The Renny pump seems adequate for stock usage. Adequate doesn't mean good but it seems to be good enough to avoid a mass recall - which is enough for Mazda.

 

I think the problem here is that the stock pump pumps much less at high RPM's than at about 6K....where most people drive...and where Mazda expected them to drive

 

You would be surprised at the in-efficiency of the pump on the 13B-REW. It is quite similar to the RX8's but flows the opposite direction. As I mentioned earlier we also have the new design for the FD (REW). These are seldom revved as high but their cooling systems are notorious for being a weak link. The pump is a big part of the puzzle although there are other factors (Providing cooling with the turbos on board has added stress to the system).

Rick was under contract with Mazda Motorsports back in 93 to build short blocks for a famous race team in the IMSA Bridgestone Supercar series, so he saw what was failing.

Paul.

 

Well, at high RPMs, there are 2 ways to remove cavitation. Lower pump speed or redesign the pump.

I'm definitely going to need one of these. More power = more heat = more sad panda cooling system woes

 

Yeah, I need some solution as well.
I live in an area where a normal, un-stressed cooling system is going to saturate.
Add to that boost, an intercooler fighting for real estate in the nose and a propensity to thrash mercilessly a motor that is already a heat-hog, and you have a potential for catastrophe.

 

"Officer - I was really only coasting at 150 mph to get my radiator flow up. It's better for the engine!"

 

^^ Heh. Sometimes, when I'm crossing the high desert, I'll gradually make my way well into triple digits and then hit the clutch and hold the RPMs up to 2500 or so.
I can lose 8 to 10 degrees that way.

 

I don't understand how improving the flow is necessarily going to reduce coolant temps . Or is that not what this pump will do ?
Or is the point of the pump more to recover wasted HP with the OEM pump ?

 

I doubt that there will be any HP increases with this pump. It is designed to flow more....especially at high RPM's where the stock pump craps out and starts to cavitate. More flow = more heat transfer from the engine to the Rad and to the air = cooler engine.....and I suppose potentially more HP from the cooler temp(dreamin : )

 

I'll take more safe than power with this motor.

 

What I'm getting at is that this is a closed system . Won't it reject the same amount of heat through the radiator no mater how fast the coolant is flowing through it ?

 

The problem is to keep the coolant moving.
When a pump cavitates, it is stalling.

 

and a simple pump curve would show (if sized correctly) that the pump pumps more flow at 7,000 rpms then 9,000 rpms...