I just moved t o Tampa, from colder climes, and I'd like my '93 rx7 to survive summer. Assuming I can only afford one mod right now, which should I do? Fluidyne 50% larger than stock radiator or vented hood? Or something else?

Radiator.

Well you should replace the rad as a matter of prevention. I used to live in South Texas and it gets hot down that way. A good alluminum rad and a new thermostat and you should have no problems. The vented hood would be secondary behind the rad IMO.

you fell off the face of the earth...where have you been at?

I went with the Koyo rad, I worried about whats under the hood 1st.

I agree with this. If you're really worried about underhood temperatures, however, go with a more free-flowing exhaust. All the heat is allowed to flow away from the engine instead of hang out and bake everything. You also get the added bonus of some HP. Beware though, there are cases where stock ECUs can't handle a full straight system. (There are cases where they do, but I wouldn't think you'd want to experiment.) Radiator, intercooler (bigger, stock location type), better radiator fluid, (Redline water wetter added) and better flowing exhaust should have you pretty comfortable. At least it would me. https://www.nopistons.com/forums/pub...#>/biggrin.png

A vented hood would not have prevented my stock radiator end tanks from cracking. Go with the radiator.

A vented hood just isn't what comes to mind when I think first steps towards a cooler engine bay. It's closer to the end of the line. My thinking order goes: exhaust, radiator, intercooler, oil coolers...etc. Good luck with the weather in Florida, we vacation there often (live in AL) and I know how freaking hot it gets.

While we're talking about radiators, what would be "better"? I'm not looking for opinions, just facts. Fluidyne or Koyo? (Money's not an issue, pure performance.)

Fluidyne is only 38mm thick, Koyo is 50mm I believe.



I got mine from M2, I think it's the Mazda Competition one? 50mm thick.

Cooling efficiency is about the same per mm for both?

I have a Koyo. It is nice. Wrap your turbos too. That'll save heat.

Really? (On the turbo wrapping.) I saw that and wanted to see if it was just hype to appeal to the ricers or for real. What about turbo? Is it affected negatively or positively?

I can run around the block hard then hold my hand right next to the wrap, and it's pretty damn cool. Granted, i NEVER touch the wrap, but I've seen quite a bit of reduced underhood temp.

Its not that solid as far as proof goes, but heatwrapping has also shown like a 7 degree decrease in air intake temps that my pfc registers. This could be also be due to the weather, but it did run later the day we installed it.

So actual turbos aren't affected either way, just underhood temps?

Just get Chuck's V mount, it'll come with a Koyo rad. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

Oh and what's the coating, jet hot??? I can't remember the name but I'm considering buying some for my exhaust manifold.

heat is trapped in the turbos. this will help increase cracking and shorten the life.

Dammit. That sucks the big ones.

Radiator

Hiya, good to see you again. I actually did pretty much fall off the face of the Earth--A year in Korea with nothing to drive but a Galloper (massively underpowered SUV). I got my revenge, though--smashed it on the front of a 25 ton truck when I forgot about how a high center of gravity affects handling.



I thought I'd be going to England next, but they sent me to Florida instead. So I guess it's time to shop around for Fluidyne and Koyo radiators, save up for a vented hood after that, and consider repainting it white or silver. The heat down here is insane already, and it's the coldest time of the year.

radiator

The radiator is obviously the best choice here. But as others have mentioned, you can do some extra things to help the underhood tempatures.



My car isn't a daily driver, so one of the first things I did was remove the weather stripping by the windshield hood area. When I am at a stop light in the summer time, I can see the heat seeping through this new opening. A few of us here in KC also have reported a degree or two cooler running; but that just may be subjective without real sensors outside the engine. But, one thing is for sure, heat is now getting out much quicker.



You could also do jetcoating, and other things. But ultimately, the radiator is a huge improvement.

Radiator first. I like fluidyne for fitment, but Koyo is cheaper. I also heard both have about the same efficiency, but never actually saw the source/numbers.

Wrap the downpipe back to the cat. You might also consider the fan mod which keeps air moving for about 10 minutes after shutting down and helps with the underhood heat soak.

I also like my Miata thermoswitch. https://www.nopistons.com/forums/pub...IR#>/smile.png

Thanks for the additional heat control suggestions--I don't have a garage or covered area to keep the car, so I wouldn't want to make any permanent holes. If I get a vented hood, I'll need to get or fabricate a cover for the vent. Pre-cat wrapping sounds safer than turbo wrapping, as long as I can maneuver my way in there to get it wrapped.

And I'll keep saving up for a vented hood and/or jetcoating, after the radiator.

PROPER DUCTING!!! I would get a Koyo ...it's more effecient and will not burst like the stocker. But without proper ducting on any radiator... you're not gonna get effecient cooling.

I guess I assumed you already had a downpipe already. But as soon as you can afford it, I'd get that pre-cat off. That alone will reduce underhood temps...alot and they've been known to fail which can do some damage. The bonus is better performance/more power. It's also a convenient time to have it jet-hot coated before it goes in. On a budget though, wrapping is cheap and effective.

dont get a hood, the only problem i had with my koyo was that i had to grind down the stock brackets for it to sit low enough to get the intercooler and such back in.

I'd like to do a downpipe as well as a radiator, but since my mechanical ability is limited to replacing the license plate (rfreeman can verify that, I helped him replace my hoses with silicone a while back), I'd need to find someone in the area with a spare weekend.



I mean, that's not a mod I could have a shop do, is it? I think that's a part they're not allowed to remove, but if I'm wrong about Florida emissions laws, someone let me know.

Don't know about the Florida emmsions laws, but this is some info about downpipes that might be helpful....



http://www.clubrx.org/default.asp?id=5&ACT...ontent=30&mnu=5



Jim

it not that bad i dont consider myself really mechanically savy and a friend an i did mine. ill be back from college in a little less that month for spring break and we could do it then i live in st. Petersburg.

Wow, nifty--I've heard fitting them in can be tricky. Probably depends on the kind--which did you get?

I should order it pretty soon if you're back in under a month--and thanks for offering to give up hours of hot sand and hot chicks to help me out https://www.nopistons.com/forums/pub...#>/biggrin.png

If I was local, I'd come help, but both mods are minor. One or the other Rad is an easier "Drop in" that fits pretty easily.



The DP shouldn't be too bad, depending on how long your stock DP has been there, and the bolts condition (if the car has seen a lot of rain/salt it can make the bolts rust and get harder to loosen, etc).



I am probably going to replace my Radiator and perhaps do the fan switch before March (Dang I better get moving!)

116,000 miles, mostly un-garaged, daily driven in all kinds of weather by all owners--Do they make super-duper-extra-strength liquid wrench?

Maybe I'll get the Fluidyne, just to be extra-certain that the radiator part is nothing but an unscrew, lift, drop, re-tighten type thing. Downpipe, I'm still not going to attempt without help or at least some on-call backup.

i would do a radiator first. lol i know thats what everyone else said too. but when i added my fluidyne it helped alot. after driving around normally without the new rad my hood would be extremely hot to the touch. after the fluidyne install it was so much more noticably cooler. its really not all that hard of a job to do either. just remove the airbox/intercooler/fan/ battery assembly. lol basically everything in the way of you seeing the radiator clearly. and then remove the underbelly tray and drain the coolant. remove radiator and then install new rad. reassemble everything and then make sure to get all the air out of the coolant lines and radiator.