Monsterbox

iTrader: (6)

Last summer with all stock plastic under the hood my car ran great, with my fan mod switch i couldnt possibly get the car over 190F at idle..even if it sat for 30mins

i have all new hoses, koyo radiator, fan mod switch

this summer i have a large smic intercooler and a custom aluminum duct. when sitting in traffic on a day 92F or above (never happens at night)..the car starts climbing in temps very very slowly. so my first thought was battery. remounted it to the trunk. still climbs very very slowly perhaps slower all i can think left would be the SMIC Duct is blocking airflow to the fans because if i pop the hood and run for 15mins in the driveway it will maintain the same temp although if tis at 200 it will not come down until shut down?

anyone else experiencing this with a large smic and duct at idle? should i look into vented hood or are there any ideas to get more airflow to the fans..the fans are supposed to push air through the i/c?

gracer7-rx7

iTrader: (16)

What exact temps are you seeing? Climbing to what?

Got pics of the duct you are talking about?

Did you bleed/burp the cooling system after you did new hoses and rad?

Did you pressure check the cooling system to see if you might have a leak somewhere?

Assuming that the temps are actually high, You should try and figure out what might be wrong rather than blindly throwing money at "fixes" that might not work. It is highly unlikely that the battery had anything to do with it.

Monsterbox

iTrader: (6)

same issue....seems much less of a problem if the hood is up at idle in the driveway but the temps still climb with fans on...they are going the right direction

could it be the duct heatsoaking and blocking airflow?

temps climb from 180 and start rising...ive always shut the car off b4 215 so i dont know if they temp would settle out at 215+ seems to me like it would keep creeping until it overheated

GOOFYROTOR

you should disconnect the fan mod back to stock to see if the problem happens and then go from there.

DaveW

See this thread - I had a similar problem that may have been related to my large PFS SMIC duct. It may be that the KOYO needs more air flow to work properly.

https://www.rx7club.com/showthread.p...=radiatorworld

SPICcnmGT

Or you could just not flip the switch to turn the fans on until 400F like the stock ECU.

DaveW

If both fans are not working (or not working well), then even switching them on may not create enough air flow. This would logically lead to temps creeping up while standing still (where the fans are the only way to create air flow). My problem was more noticeable while driving under load, where the temps would creep up at ambients above 80F.

Mahjik

iTrader: (1)

IMO, this is more of the cause. Most people increase the size of their radiator without being able to increase the amount of air to it. A larger radiator can just become a huge heatsink which is why I recommend stock sized replacements like the Fluidyne for street driven cars.

Monsterbox

iTrader: (6)

first of all,
the fan mod allows me to turn them on early, the car will still control them as normal if i dont flip the switch

second,
if I am cruising down the street at 55mph with a/c on full blast...no problems whatsoever and it doesnt even creep above 181F AND when I pull over, the duct is cold and I/C is cold from the forced airflow

However, If I am in stop/go/stop traffic for 10min and pull into a gas station, popping the hood burns my fingers underneith, the duct is too hot to physically touch and the intercooler is on fire as well....the car blowing up from the fans is like a hairdryer

So im beginning to believe what mahjik is saying about not enough airflow to the rad.
1. duct is aluminum and retains heat more than stock plastic duct..not to mention its 3 times the size
2. you cant even see the passenger side fan (although the stock crap blocks them entirely)

Any ideas on improved fan flow? Larger fans available? Cut vents in the hood? remove weather stripping? Reverse Fans? Wrap the Downpipe??????


Note: battery has been relocated to storage bin, ground kit has been removed, AST has been moved to battery's orig. location

DaveW

That statement makes me believe that you are not getting enough air velocity from the fans (it may be that one of them is not running, etc., or that the IC duct is almost totally blocking air exit from the fans) - if the air were moving fast enough, it would NOT be that hot. At idle there is NOT very much cooling capacity needed, and if it is only getting hot then, and the air coming out is hot, it almost certainly means the fans are not flowing enough air, for whatever reason.

The fact that you get good cooling on the road while driving means, IMO, that the rest of the cooling system is in order, and there is enough room for air to flow through the radiator itself.

scotty305

iTrader: (2)

Does your car have one oil cooler or two? Remember that the oil coolers don't have any airflow when the car is sitting still, unless you've added an aftermarket fan.


-s-

Mahjik

iTrader: (1)

I don't really think it matters that much since he's comparing his temps before and after his mods (i.e. if the oil system hasn't changed, it shouldn't really be a variable for his problem).

IMO, it has to do with the stop and go traffic combined with the larger radiator. The larger radiator just becomes a big heatsink when the car isn't moving. The stock fans were designed with the stock radiator in mind so some temperature increase is bound to happen with the added thickness.

IMO, 92C is nothing to be worried about. As long as the stock fans are able to keep the car below 110C in stop and go traffic, you are fine.

Monsterbox

iTrader: (6)

im sure it would stay below 110c to make it through most traffic....but it just concerns me because if it flip the air on i can watch the needle rise on my defi gauge...and it doesnt stop rising...it seems like if i sat for 45mins with a/c on im sure the car would ruine

Monsterbox

iTrader: (6)

fans are pretty much new...replaced them when my old set screwed up

DaveW

Well, if you're sure the fans are operating properly, then the IC duct (or something else)HAS to be blocking airflow from the fans enough that you can't get the cooling you need.

And, IMO, heatsoak (or having the radiator as a heat sink) is not the issue. Eventually (you've watched it for long enough time periods) the fans would cool it off if that were the case. The issue, IMO, is that the fans are not moving enough air for your radiator setup, thus letting the temps creep up. And, that has to be due to either the fans not operating well (but you said they were new), or the airflow from them being restricted.

Mahjik

iTrader: (1)

Dave, we are actually saying the same thing. The radiator is turning into a large heatsink because the stock fans are not efficient for the larger radiator core.

Many people have observed slightly higher temps with the Koyo in street usage. The question that needs to be answered is does his temp ever even out while the car isn't moving or does it just keep rising regardless of the fan operation.

DaveW

^^^

Yup - we agree!

DigDug

I'm running a Koyo with stock fans and have no problems at all in 90+F temps we're having lately. I've been running the AC in stop-and-go traffic a lot too, and temps stay completely in check.

I'd guess that gnarly-looking duct gets pretty close to the back of the fans. Why don't you take a photo from the side down in there showing profile?

xurotaryrocket

That car used to be mine. I installed the Koyo in it. I did realize some higher temps in stop n go city driving as compared to the stock radiator. However temps always fell rapidly on the highway assuming it wasn't blazing hot outside. Of course this was in OH and he is in the south... much hotter.

Also, I never had a SMIC and duct that big in it. I used the stocker or a Blitz which is relative small. It allowed plenty of air around it and used the stock air duct.

The "fan mod" switch always kept temps in check.

I agree that the big *** IC and duct is reducing air flow efficiency. Also those intakes can't be doing anything but sucking in blazing hot air off the engine. Try to get an M2 box or a PFS box or something. It will at least provide a small buffer for intake air temps.

You could also try upgrading your stock fans to an aftermarket puller. That would solve alot of problems and you may not even have to seal off/duct the radiator.

One more thing would be to use limit your boost to stock levels. It will produce less heat/stress on the cooling system for the summer. Anyone else have input on this ?????

PS - Zach, the engine bay looks mean !!!!

-Ryan

Monsterbox

iTrader: (6)

hm, what are some aftermarket fans out there that would wire into our plugs and relays and fit on the radiator mounts?

i always run 10psi...once in a while i bump it up to 12.4 thats max

gracer7-rx7

iTrader: (16)

Might want to double check that both fans are actually coming on. I just noticed that my driver's side fan is not working.

adam c

iTrader: (2)

New fans won't work if not wired properly. Checking to see that they are both working should be your first priority.

If the radiator cools properly when in motion, then ariflow being blocked isn't the issue.

DaveW

This is the OBVIOUS 1st step. Make sure the fans are actually running properly!

One of the symptoms of slow fans is HOTTER THAN NORMAL air coming out, caused by the air moving slowly!

MADDSLOW

iTrader: (11)

Quick question off of this... if you park your car after driving to run into a store or something, and come back out in like 10-15 minutes, and temps are around 116-120C, can this damage anything in the engine? It drops to the 90s within a few seconds, just wondering if that hot coolant sitting still can cause any harm.

DaveW

The lower the peak temps the better, obviously, but stock FD's always do this as the heat stored in the metal transfers to the coolant after shutdown.

Do you have the FC thermoswitch? This will cause the fans to come on sooner and reduce coolant temps.