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-   -   why does coolant make a double pass (https://www.rx8club.com/series-i-tech-garage-22/why-does-coolant-make-double-pass-209878/)

dannobre 01-07-2011 01:52 PM

When your ECT's are in the 245+ area on track you will get much more obcessed as well ;)

Too cool isn't a problem...it's easy to let the oil and coolant thermostats up regulate it...but it is engine killing to let it go the other way

Just because it isn't an issue with you doesn't make it a non-issue :)

I am currently looking at a diff cooler setup for my car..and possibly a transmission one as well....I have logged temps of the diff over 325 degrees...and have heard of racecars close to the 400 degree mark after a cooler failure.....that is way too hot. Is this relevant to 99 percent of people....no...but it doesn't make it irrelevant ;)

PhillipM 01-07-2011 01:59 PM

Some of us are at full throttle for minutes at a go, it needs all the cooling it can get ;)

HiFlite999 01-07-2011 02:03 PM


Originally Posted by mazdamaniac (Post 3840810)
except for the ppf, which is a deal-breaker.

ppf = ?

MazdaManiac 01-07-2011 02:15 PM


Originally Posted by dannobre (Post 3840969)
Wish I could have gotten that engine :)

Yeah, I got lucky on that one.
I even got the alternator, starter and A/C compressor!


Originally Posted by HiFlite999 (Post 3841036)
ppf = ?

Power Plant Frame.

The '09 transmission won't bolt up to the series I PPF.

olddragger 01-07-2011 02:15 PM

The 09 PPF is noticabily lighter but i dont know if it will fit the S1 model. The 09 trans can be used with the S1 PPF.
The 09 model also has additional designated cooling fins and under car spolier that direct cool air to the diff. Pretty sweet set up.

I think some are confusing cooling the percieved hotspots with overall cooling. Remember just because your temp gauge says the coolant is at 190F it doesnt mean that additional cooling is not needed in some areas.
I know some builders address the exhaust ports cooling jackets with their own modifications.
od out for now--have to go install trans etc.

MazdaManiac 01-07-2011 02:22 PM


Originally Posted by olddragger (Post 3841054)
The 09 trans can be used with the S1 PPF.

Uh, how? (Without fabrication, I mean - you said it was bolt-on.)

The mounting bosses are on the opposite side.

dannobre 01-07-2011 02:28 PM

so you need to change to the Series 2 PPF....the diff is the same I imagine.....they have used the same one on a lot of cars

MazdaManiac 01-07-2011 02:45 PM


Originally Posted by dannobre (Post 3841079)
so you need to change to the Series 2 PPF....the diff is the same I imagine.....they have used the same one on a lot of cars

IIRC, the mounting boss bolt pattern on the SII diff is different as well.
I only got to look at the two PPFs serially, so I couldn't do side-by-side measurements, but the offset of the upper and lower flange saddles looked weird on the SII PPF.

We're working on a replacement PPF for the SI, so we will look into the SII PPF and see what is up in the next few months.

dannobre 01-07-2011 02:47 PM

That project still in the works ;) Charles has been talking about that forever LOL

MazdaManiac 01-07-2011 03:16 PM


Originally Posted by dannobre (Post 3841097)
That project still in the works ;) Charles has been talking about that forever LOL

Yeah, we finally got moving on it last week. Several other projects as well.

DocBeech 01-07-2011 05:33 PM

My engine peaked at 242 after 10 laps at full throttle at texas motor speedway. Currently I am getting a sprayer to see if that solves the problem short term. I will also be installing the fan system on the oil coolers and adjusting my antifreeze levels. I am also looking into the koyo radiator, I am going to see how its different from stock.

The transmission cooling is also a necessary evil for me. Again here street temps reach 130+ in the summer so that doesn't help at all. I didn't think about recording temps on the diff, thanks for the suggestion. I am looking for a mounting situation to the transmission cooling system now, but it might require some duct work.

MazdaManiac 01-07-2011 08:58 PM


Originally Posted by DocBeech (Post 3841315)
I will also be installing the fan system on the oil coolers

Fans block more air than they move in all conditions other than when stationary.


Originally Posted by DocBeech (Post 3841315)
I am also looking into the koyo radiator, I am going to see how its different from stock.

The Koyo rad has been repeatedly proven to increase coolant temps because it restricts airflow.


Originally Posted by DocBeech (Post 3841315)
The transmission cooling is also a necessary evil for me.

As noted above, there is no practical way to cool our transmission.

DocBeech 01-07-2011 09:09 PM

Well I have to come up with one solution or another. The fans worked for a guy in houston that did it.

If the koyo radiator is crap then I will have to look into other solutions. I know copper is a wonderful material for using in radiators, but extremely expensive to have one custom built. Which would probably also include a different water pump if I am going to use a custom radiator.

Adding a second radiator to cool the water maybe an option for the back of the engine. I havn't put a lot of thought into it, or the logistical running of the system that way, but it would take an electric water pump, and some design work. I don't think it would give you a huge advantage for all the weight added.

As for the transmission and differential Im sure there is a way to to do it, it would just take a bit of machine work. Probably a lot of machine work, but I am already considering running the series 2 transmission if it is that much better than what we have stock, that would probably be the easier and cheaper way to go. Im sure there is one sitting in a junk yard within a couple hundred miles as often as people wreck around here.

MazdaManiac 01-07-2011 10:30 PM

You have been on the forum for 6 months or so. Have you not noticed that ALL of the things you are talking about have been discussed ad nauseum for the last 7 years?

Brettus 01-07-2011 10:34 PM


Originally Posted by EricMeyer (Post 3840488)
Side note: The 09-10+ tranny is near freakin' bulletproof. We have 4 of them now and they are rock solid. They weak link is the input shaft which is about 1/2 the diameter of the 04-08.

So ..... not strong enough for a high torque turbo application ?

DocBeech 01-07-2011 10:38 PM

Well like anything in the performance industry there really is no beaten to death. You think thats bad? Try the forums for 1950s porsches. Now some of those are old discussions. But if its not talked about then it can't be corrected. Sometimes even new ideas come up that can help an old idea work. Thats the entire point of discussions. It doesn't matter how old it is, it matters that the idea is brought up until it is fixed.

MazdaManiac 01-07-2011 10:47 PM


Originally Posted by DocBeech (Post 3841515)
It doesn't matter how old it is, it matters that the idea is brought up until it is fixed.

I said nothing about the discussions being old. I said they were over done.

Also, I didn't say that there were no solutions, either.

Lemme try again:

You have been on the forum for 6 months or so. Have you not noticed that ALL of the things you are talking about have been discussed ad nauseum for the last 7 years and largely addressed in a satisfactory fashion?

dannobre 01-07-2011 11:08 PM

Cooling of the transmission is quite possible....it's doing it in a way that is "street car" acceptable ;) Most won't want to add ducts to the rear quarter panels to provide cool air to a rear mounted cooler :)

DocBeech 01-07-2011 11:12 PM

Hmm I see the same thing I always see. What works for one person doesn't always work for the other. Which isn't surprising since we are all dealing with different conditions. The other reason why I am very sceptical about when one person says you can't do that, or that it doesn't work is because people have lots of different mods. Two people might buy a koyo or mishimoto radiator and install it with completely different results. I know whats worked for me in the past. I have seen and had people on here say that some things dont work, when I have had success with those same adaptations on the track, and sometimes even in the shop when I was a mechanic.

MazdaManiac 01-07-2011 11:15 PM

We are talking about scores of people with the Koyo. Maybe more.
In every instance where the temps were verified in a racing environment, the Koyo failed miserably.

Dude - my work is done here. Use the search button.


Originally Posted by dannobre (Post 3841526)
Cooling of the transmission is quite possible....it's doing it in a way that is "street car" acceptable Most won't want to add ducts to the rear quarter panels to provide cool air to a rear mounted cooler

Not to mention the high-temperature pump motor and running an appropriate viscosity oil. And the complete tear-down of the tranny to fabricate the windage and inlet/outlet. And the plumbing.

dannobre 01-07-2011 11:31 PM

That's the easy part :) I just finished TIG welding my Diff cover so I could add the extra port for the diff cooler :)

nycgps 01-07-2011 11:32 PM

Doc, MM was right the radiator topic is way over done ---- but lemme tell ya my story.

I had no issue with Koyo, I beat the shit out of it my temp is still ok. BUT ---- I never went to a track with it so I can't verified it. Plus I had RB flash which turns the fan on much sooner (10 Celsius earlier)

Then I swap it with Mazmart/Ron Davis Radiator. same as above, beat the shit out of it no issue, Even with stock flash (cuz the MSP16), temp was around 95~ ish Celsius. I had some run @ English Town. it works ok.

Reason for swap? Just wanna try "something new"

Now Im on Knight Sports Radiator, Made by Koyo with Knight Sports Spec. Its more of a "N-Flow" design. so the outlet is different (it came with hose and everything) Its almost double the size of Stock rad (like 53 mm I think) still fits. Will try it at English Town this coming spring.

DocBeech 01-07-2011 11:34 PM

You gonna run it on the track? Id love to see what the results are. Also you are reflashed back to stock? or still on the RB flash?

nycgps 01-07-2011 11:38 PM


Originally Posted by DocBeech (Post 3841554)
You gonna run it on the track? Id love to see what the results are. Also you are reflashed back to stock? or still on the RB flash?

Koyo --- had RB flash

Mazmart/Ron Davis --- Flashed by MSP16 - ran @ English town. couple of times. its not a high speed track, lots of corners.

Knight Sports --- Just installed it like maybe a little bit more than 1/2 yr ago. back to RB Flash about 3 months ago.

EricMeyer 01-08-2011 07:57 AM

Mr. Doc,

I applaud you for your non-conventional approaches to problem solving. I'll suggest to you that we've followed an approach over the last 4 years with 5 different RX-8's using road racing industry approaches and have addressed the issues you discuss to the point where they are easily manageable.

Radiators: There are several on the market. We probably have the most expensive and some overkill with a custom dual pass, extra thick C&R radiator. Again, there are several that are adequate, we chose a leading NASCAR, IndyCar, Baja, Rolex radiator company etc. In summary, there are radiators out there that will work and will reduce your temps very easily.

Oil Coolers: I've tried 6 different oil cooler designs with and w/out an oil thermostat. Anything from super huge pizza box size Setrabs dual systems using the MazdaSpeed front bumper to to smaller Fluidyne units and the newer series 2 front nose. Add to this various radiators and I think I'm well qualified to share with you results.

We have been using Motec data acquistion since 2007 and I have more temperature data than the NASA space program.

The bottom line is you don't need water sprayers or a second cooler. What you do need is an aftermarket radiator that has the corners of the air filled in or blocked off so incoming air MUST flow through the radiator. This is a simple technique that so many people miss. A $5 solution at the hardware store and some window foam. Paul has helped us recognize when there is stock waterpump caviatation (thanks Paul). Under high rpm load (as in a long uphill in 5th gear on the Mosport backstretch reaching 130mph range) the stock waterpump with cavitate and/or not perform optimally and this environment will see temporary water spikes. The pump is an easy replacement. The impellar is a gorgeous little piece of work. Get one and it will help PREVENT higher temp spikes under high load. I really doubt many of the people on this forum have this issue. It is more preventative than anything and well worth it. The stock water pump impellar is wimpy, wimpy, wimpy. Oil coolers: I would highly recommend getting an aftermarket oil cooler setup. HIGHLY. The stock oil coolers have been used in the original SpeedSource cars from 2004 run in Grand-Am ST without issue. Granted these are 2,700 lb dry weights but they run a 5.12 diff and combined with racing has much higher avg rpms than any stock setup. This car configuration has ran 6 hour endurance races and near WOT numerous times without issue----in stock oil cooler config, stock waterpump and aftermarket Ron Davis with MazdaSpeed nose---in the draft. WOT. For hours. With a 5.12 diff. For hours. In the heat. I'll suggest to everyone that there is no great punishment this car has or will see then this environment. Water 220'ish. Oil 230+ ish. Too high for us.

Our current solution (which I'd be glad to share more in detail, please e-mail) allows for 190F water and 210F oil all day long, in the draft, 5.12, WOT, uphill, 8,700 rpm, .89 Lambda, 1,650F EGT. No problems. I'm not being sarcastic here but please note that this is easily done without an electric water pump, heat exchanger or any other non-conventional approach.

My point is that very safe operating temps are easily achievable. Please contact me if you'd like details that will buy you engine insurance quickly and easily.

Respectfully, the guy who has tried more w/these damn cars than anyone else I've talked to.

Eric


Originally Posted by DocBeech (Post 3841465)
Well I have to come up with one solution or another. The fans worked for a guy in houston that did it.

If the koyo radiator is crap then I will have to look into other solutions. I know copper is a wonderful material for using in radiators, but extremely expensive to have one custom built. Which would probably also include a different water pump if I am going to use a custom radiator.

Adding a second radiator to cool the water maybe an option for the back of the engine. I havn't put a lot of thought into it, or the logistical running of the system that way, but it would take an electric water pump, and some design work. I don't think it would give you a huge advantage for all the weight added.

As for the transmission and differential Im sure there is a way to to do it, it would just take a bit of machine work. Probably a lot of machine work, but I am already considering running the series 2 transmission if it is that much better than what we have stock, that would probably be the easier and cheaper way to go. Im sure there is one sitting in a junk yard within a couple hundred miles as often as people wreck around here.



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