The front mounted oil cooler kind of doesn't make sense to me... they stick it in front of the radiator, so that the air has to go through the oil cooler AND part of the radiator, which is Bad. It preheats the air that goes through the radiator and it decreases the pressure drop across either one of them. So unless you make ducting *or have an A/C consdenser installed* (it fills the "hole" above the oil cooler) the air will preferentially go right over the oil cooler instead of through it.

The only problem with the shorty radiators, is they don't offer as much thermal *capacity*. Important for sprint-and-rest style competition.

 

There's some good stuff kinda piling up here.

I personally don't like the header wrap and don't think it does a whole lot. Ceramic coating is awesome but fairly expensive. Rotarygod is right about the water on the header thats just silly to think the water will rust it. I had a fuel hose weeping fuel on the header for about a week and could not find the sorce of the raw fuel smell because it would drip this tiny drop on there at like 2 minute intervals and when it hit it basically disenegrated instatly. It didn't burn or sizzle or any of that crap I mean it hit and bam it was gone. The ehaders are really hot on these engines. I wish my laser temp reader thing could read temps that High I'd be interested to see what temp it really is. So water burns slightly slower than fuel but it vaporizes on contact with the header as well I'm sure.

Here's another one for people to think about:

Transmission temperature.

Our cars are actually quite old when you get down to it. How much do you think of the engine bay temp comes from radiated transmission heat? Would it be left if the trans was rebuilt with new bearings and synthetic oil? Or better yet with a trans oil cooler? you know a fitting on the drain that leads to a pump that leeads to a cooler that goes back to the fill hole of the trans. They do it on race cars I'm wondering if it's beneficial for street cars as well. Just nobody wants to be bothered with it. The cooler could be mounted in the rear of the car. or under it. Or in a rear wheel well, Or in the glove box lol just kidding on the last one.
I do know the oil has to reach an optimal temp to be at the right weight but I have never seen the temp of transmission oil mentioned anywhere.

How can a honda manual transmission put up with the same temps as every other companys transmissions but do it only using regular engine oil for lubrication? What's missing from this equation? And don't say because they don't make any power even though its funny to say. There is definetely more Honda street cars that run fast times at the track then any other make of car not including domestic vehicles. There are tons of hondas with double and triple stock hp and still running stock transmissions. I know the same can be done on a rotary, or a 4G63, or a 2JZ but they all have heavy weight gear oil.

I already know clutch heat is significant but basically there's nothing you can do about it so it's not worth thinking about. I like to cool mine with oil personally lol.

Also remember the exhaust is right next to the trans.

A diff cooler would be good for people driffting I've thought of buliding one myself. Anyone ever touched a diff after a few minutes or hard driving. It's f-ing hot!!! Sometimes hotter than the mufflers.


Anyone ever think of moving the oil cooler to a top mount position with a t2 hood? But using a square one that fits the size of the hole better? Just thought is was an interesting idea. Or building a water cooled oil cooler that doesn't use the stock cooling system? Just throwing ideas out there brainstorming.

Why does a RX8 get away with the type of oil coolers that people say don't work well or don't cool enough for rx7 engines? I know the oil temps are very similar in the RX8 engine so what's the deal?

I wonder if anyone has ever built a heatsink for the engine itself. It would have to be on like a carbed 12A with no emissions rack or something though. Just a giant heatsink of aluminium on top of the engine with like a few hundred 10 inch long plates sticking up. I know it would look stupid just throwing stuff out there.

How about just moving the radiator further away from the engine. In the nose more laying at a steeper angle? So the engine can't help heat soak it as easy.
This would require a non-stock radiator though. And mine can't fit up there I checked it's too big.

 

Yeah the air passing right over the oil cooler with no ac condensor is what worries me as well. I was thinking of laying the oil cooler down flatish and cutting a hole in the undertray then riveting a small scoop to the undertray on the bottom to pull air thru the cooler. Oh the scoop opening would be facing to the back of the car not front. I thought about front first and then decided it may work better the opposite way plus rocks can't hit the cooler that way

 

Because the headers are always hot, and never cool off even when the engine sits overnight especially in humid areas.

Wrapped headers that I have seen typically have red stain seeping through the wrap, and if you remove the wrap, the headers are badly rusted and there is actual scale clinging to the wrap. It's not pretty at all. On the other hand, none of them ever seemed to actually rust *through*.

I'd have to say none. The trans isn't in the engine bay. The exhaust sitting next to the trans probably radiates a ton more heat.

Most manual transmissions anymore use ATF not gear oil. ATF is basically 5W20 with an additive package designed for friction modification instead of combustion by-product absorption.

If your clutch is getting hot enough to be a problem, you're doing it wrong.

The engine heat doesn't heat soak the radiator. The coolant temps rise a bit after shutoff because the engine temps are, by definition, hotter than the coolant, and it's allowed to equalize. (The rotor housings can exceed 400f around the spark plug holes!)

The coolant may also start boiling after shutoff because of the loss of water pressure. This can be helped by a *good* electric water pump, or better yet a one way clutch on the pulley so it is belt driven but may be overriden by an electric motor if desired.

One of these days I will get around to putting a pressure tap on the cooling system. On some engines the water pump can be responsible for 50+psi of water pressure, but I have seen no figures for any rotary.

 

we roadrace a honda, the trans isnt any better than the rx7 one, 3rd gear synchro is still the problem, and thats at 140hp....

on the rx7 the exhaust is hot enough to cook the passengers shoes at the track, so i'd think the trans is getting heated up by this too

 

http://www.s2ki.com/forums/index.php...pic=324009&hl=

I just picket up a spare hood today and may give this a go and do some testing. My only concern would be the additional turbulence increasing drag.

 

Very interesting thread. I do have a spare hood laying around. Maybe I can make it my track only hood

 

I can't find any pics of it, but the early Renault 5 rally cars (the front drive ones, not the R5 monster) had a modification done to the hood hinges where the hood side of the hinge was turned from a closed circle into a slot.

So when you came in for service, the hood was opened, and then pulled off with no tools required.

Picture the hood coming off similar to how the 1st-gen sunroof comes off, and you'll get the picture.

So, if you make a track only hood, try doing it that way...

 

i remember reading about someone making the hood hing pins removable, be pretty simple to do

 

this would be probably simpler but still requires 2 guys to remove it. Peejay's way would just be a single person's job. I think I just opened myself a can of worms

 

What about putting the oil coolers more under the car at an angle. I guess to get a cooler radiator, is to get a none OEM one(they are huge) and fab up custom mounts. Than put 1 12" fan on the front, and 2 6" fans on the back to increase airflow. Fine or make a custome hood so hot air can escape; a hood that has like exhaust vents at the end of it. On the FD forum, a member made a neat header cover out of aluminum, it helped keep hot air out of his oil cooler and heating up the intake pipeing. Instead of heat wrapping the header(gets too hot to help IMO) Heat wrap the exhaust, so the heat in the car could go down a couple of degrees.

Thats all I could think of. Hope it helps!!

 

I like the S2000 hood idea as a start.

One of my ideas was to build a "trap" behind the radiator in front of the engine. This of course would only work on a car with a electric fan. The trap would be flat and vertical close to the engine adn the two sides would be triangle shaped to match the slant of the radiator. The top of the trap would come on close proximity to the hood which would be vented to outside in some way. So the air would pass through the mouth of the fascia through the radiator and up through the hood to outside again. This would also keep the engine compartment from heatsoaking due to the radiator and in conjunction with the header heatsheild I mentioned should cut down on the overall engine bay temps.

If you know what a J hood is it would be kinda like that. It would require possibly moving the radiator a bit more forward or leaning it more forward on the top. At least in my case it would.

BTW does anyone have a white NA hood near Abilene TX they would be willing to trade for a T2 hood???
I'd like to get rid of this thing I don't care for it much. Mine is not aluminium its a JDM Steel one it still has the factory stickers on its underside

 

Just kinda going back the transmission there for a bit, would the tranny help dissipate quite a bit of heat from the engine by acting like a heat sink? I was filling up my tranny today, had just done a run (20 minutes normal driving) and the area around the starter was the hottest, so hot that i could barely keep my hand on there. If it doesn't help dissipate too much heat, would putting and insulating spacer or gasket of some sort help keep things cooler?

Also anyone know why the second gen trannies have a vent as oppose to the first gens not having one?

 

The GSL-SE trans has a vent. It was probably just thought of later and rather than start making new transmission for a vehicle already in production they saved it for the 13B equipped cars.

Also the header wrap certainly does help. I wrapped my RB RR header with it and I can hold it now without burning my hand. My RE-Speed strut bar actually feels hotter than the header when I open the hood.

For a louver you could try looking here. http://www.hrpworld.com/index.cfm?fo...action=product
Fairly cheap and mounted on the forward section fo the hood would help draw air through the rad and straight out. Also would improve high speed stability by allowing the air that would normally lift the hood to just be vented out on top of the hood.

 

Well finally got my hood done as well as an air dam for the rad. All in all I'm happy with the look of things, it'll take a bit for me to notice if there are any results to cooling though.

https://www.rx7club.com/fabrication-250/air-dam-hood-vents-847209/#post9304732

 

The GSL-SE had a bolt-on vent, the FC trans had it cast in, as well as having a ringed bellhousing.

Judging from the angle and location of the "vent" on the FC it appears to be more of an *inlet* than an outlet.

I am not sure why they felt it necessary. Certainly the un-vented ones don't seem to cause any clutch issues, or suffer any undue leakage. (The clutch and flywheel act like an inefficient centrifugal supercharger)

 

my favorite was the octagonal RE amemyia clutch, due to it being symmetrical it was louder than the car! wooooOOOOOoooooooooooooooo

 

Ya i couldn't remember if it was an inlet or outlet, assumed for outlet, but if its an inlet, brings in the idea of maybe its cooling the engine from the back side as oppose to cooling the tranny perhaps? Or could something like that be rigged to cool the back of the engine (maybe not so effective for 2 rotor, but 3 or 4 rotor engines?)