So I've been dealing with some heat issues for a bit.

93 DB2 GSR B17A1
​​​​​
Originally my thermostat got stuck (cold lower hose) and the pressure took out my rad (started leaking) because the cap didn't relieve pressure. I was about to install my turbo at the time and would have needed to switch to a half rad anyway.

Swapped in the aluminum aftermarket half rad from my EG and put in a new thermostat. Seemed better but still sometimes seemed like the lower hose was cold. Took thermostat out and tested it looks. Seemed to open fine. Took thermostat from EG out (also has a B17A1) and tested both side by side. Seemed to open about the same time for both. Noticed a small hole in the metal surrounding the valve on the cold side, where it was shouldn't really have affected anything but I put the EG one in anyway. Rated for 180 F.

Since then I haven't noticed a time when the lower hose has been any colder once warmed up. Most days I haven't really overheated, only when it's hot out and not moving much. I do have an aftermarket electric fan that comes on by ecu at under 50kmh and above 85c.

Running water with maybe 10-20% antifreeze at the moment.

Turbo is now installed with a water to air intercooler and I haven't had the greatest luck with IATs either.

I just installed a 2nd heat exchanger in the intercooler loop and a 2nd pump for good measure as well as wanting to have less heat directly in front of the radiator by splitting it across both sides of the car (originally the single exchanger was on the rad side)

I am using a FrozenBoost type 20 with 2 inverter water pumps from a Prius V. One pump can easily do over 360gph without any head although when testing putting thumb over the hose decreased flow a far bit but two should help and my system shouldnt really have any restrictoons. Reservoir feeds pump 1 which feeds the two daisy chained exhangers mounted in front of the AC condenser and behind the PS cooler lines. Then into pump 2, through a fill neck, the intercooler and back to the res.

Even before adding the 2nd exchanger and 2nd pump I didn't ever see the temp rise much during heavy boost maybe 5c after a couple good pulls, so I don't think my intercooler is struggling with boost at all.

I did shave down an IAT sensor but I haven't installed it yet. I have skunk2 pro manifold with IAT sensor on the manifold. Also have a hondata intake manifold gasket and coolant lines to throttle body are looped.
​​​​​​
Today it is 20°C outside. After letting the car warm up I went for a quick drive. IATs were around 42°C, didn't really rise at all.with boost, if anything went down with boost.

On the highway at 100km/h and just barely touching the gas to keep going the IATs did not drop under like 41°c today. I have seen them drop a bit lower, down to maybe 34°c (before 2nd exhanger and 2nd pump) but it wasn't as warm out that day, maybe 10-14°c.

ECT today got as high as 97°C and I wasn't boosting much, in fact about half way through my test run I stopped boosting just trying to baby it at 100kmh to see how low I could get the temps. I couldn't get much lower than 95°c ECT and 40°c IAT. I feel like it wouldn't take much boosting to get overy 100°C.
​​​​​
On a 20c day (before 2nd exchanger and 2nd pump) after parking the car for 15min I came back and IAT was like 63°c. Car didn't like that. It came down to 40ish pretty quick though once moving again.

I used some DEI reflect a gold and it helped a fair bit with the pipes getting heat soaked. My piping crosses over my hot side and behind the turbo.

This is a WIP so please don't judge my bay


​​​​​
Seems like IATs/intake manifold are getting heat soaked easily. I'm wondering if eliminating the reservoir and/or changing the position of the pumps/modifying the plumbing would help at all. But maybe my sensor is more reading my IM''s temps instead of actual IAT? I will install my modified sensor soon but wondering if I should just move it elsewhere

The IC itself and heat exchangers stay relatively cool to the touch when the pumps are running. If left idling with the pumps off and rad fan on blowing heat towards the IC and left to get warm to the touch, once turning on the pumps it takes like 30sec or less to get cold again.

I feel like my engine itself is running a bit warmer than it should and if it is, fixing that should lower underhood temps including at the intake manifold.

I haven't noticed any loss of coolant. Haven't smelled any unless it was venting. No white smoke or smell in the exhaust. No bubbles in rad but you can tell it is flowing (so waterpump isn't completely failed..doesn't mean it's good though)

Another odd thing is an almost hissing sound from the drivers side of the engine that is only there when warm but it also vaguely sounds like it could be a warn bearing. The sound does not persist when there engine is stopped, so while the sound first made me think maybe coolant pressure was venting out the sides of my water pump, you would think it would continue for a few sec after the engine stopped due to there still being pressure in the system. Also no evidence of missing coolant or mixing.

my next steps would be to check my waterpump and then head gasket but i thought I would ask here for any ideas. With my luck there's probably a pin hole leak in the HG and/or waterpump corroded. I never had issues in my EG with the same engine (both have b17a1) and same same rad and turbo setup (swapped from the EG) but I guess it's time to pull the valve cover

i also wonder if anything else could affect it a lot like maybe a cam off a tooth. I have always felt like maybe its always been a bit warmer to the touch than it should be when working on it. Often Icant touch the VC without saying ow. Haven't hooked up my egt yet. Dizzy and ecu are syncd at 16°. AFR is like 14.7-15 at idle/low load and 11.5-13 in boost depending on how much boost..anything above 2psi or so is 12.5 or richer. Timing is stock for NA part of map and otherwise it's approximately 1.25° per psi retarded at max boost.

​​​

 

uhhm...WOW. That's all I can say for now. LOL

 

should I have just posted "my carr overheat plzhelp"?

 

Nah, just gotta ask the right question is all!

Your ECT isn't the MAJOR issue here, it's your IAT you need be concerned about. As you say your setup is work in progress, good, add a few things to the mix! I would start with insulating all your cold pipes; exhaust wrap those for sure. Wrapping exhaust can help but be careful, over time this can cause some accelerated rusting of manifold and downpipe, etc. Check and double check your timing. This can contribute to high temps if it is EITHER too high or too low. Even timing that is excessively retarded will heat up your exhaust too much; in turn, heating up your turbo and causing lots of heat soak. If the turbo is really close to your radiator, you're heating that with heat from the turbo and so on. Better fan also? I didn't happen to notice what fan you were running; stock or? Doesnt hurt a bit to also have it come on at higher speeds. 50KMH (around 32ish MPH ? ) is low. Change that to come on below higher speeds. I have mine set below 90. I see IAT around 110 cruising- with the new setup on 90F degree days. After a few hard pulls, the IAT actually drops a bit; stock fan and shroud, no thermal wrapped ANYTHING, and ECT usually hovers around 175-180 with 60/40 water/coolant (haven't flushed from winter yet. Lol!)

Look Into addressing those IATs!

 

If the water is flowing to fast it is possible that the heat exchanger isn’t doing it’s job, kinda like if you took out your car’s thermostat your car would overheat during summer. If you was using a ice box I would want a faster water flow to keep the core ice cold, but a heat exchanger needs time to pull out the heat as the water passes through it.......just a thought

 

Eh..I more think now that person just has a negative opinion of me..wasn't asking any specific question, just for suggestions and figured the more info the better.

I think that actually it's the reverse. That ECT is my issue. I was totally in line with your thinking until reviewing data from the last few days since adding 2nd exhanger and pump, I mean, that's exactly why I added them. I've been doing what I can to work on IATs.

I can boost hard for a while (longer than I ever normally would on the street, holding the brakes) and the IAT only goes up maybe 2-3°C. In fact, when I go into boost normally the IATs drop by 2-3°C. That same brake boost event brought my ECT from 92°C to over 101°C. It seems like it has no issues keeping the adiabatic heat in check.

IAT slowly climbs as the engine warms up and under the hood gets heat soaked. My pipes do cross the turbo and taping did help there a bit but I feel like my IAT sensor is measuring more my intake manifold itself rather than the air because any time I give it throttle (even without boost) so that.air is passing over the sensor the readings go down!

Looking at the log..before the mentioned boost event.. I was at 92°C ECT and 45°C IAT. Opened the throttle a bit (6% tps) and IAT went down to 40°C in under 30sec..cruised a bit more until I went full throttle at which point the IAT was 41°C. By the time i let off, it was back at 41°C dipping to 39°C mid boost event. Boost event was a full 20sec. ECT started at 92°C and ramped to 101°C within 15sec of finishing boost. Speed was approx 100kmh so airflow should have been fine.

The fan is aftermarket from local speed shop. First one I got there was great..figured the 2nd one would be the same but it seems weak. Gonna probably fix the first one I got and swap them. Going to add some smaller fans behind the condenser under these turbo.

I don't think the turbo is too close to the rad but it does heat my charge pipes a bit. I want to maybe see if I can run them under the turbo instead of above.

Started wrapping the exhaust pipes. The cold pipes are mostly wrapped with dei tape which helped.

I took some video today and there is definitely a hissing-ish sound when the car is up to temp. As I said to me it sounds like what I would imagine pressure escaping from the sides of the water pump would sound like but also kind of sounds like a worn bearing. Except I haven't noticed coolant loss that I haven't attributed to overflow, it doesn't continue when then engine is shut off even for a second and I would think that I would see some dripping or something out the timing cover.

I let the car cool off today bit by bit and checked every 10°C or so for the sound and recorded it. It definitely got quiter as it was cooler.

I think my best bet now is to inspect/replace the water pump, remove my IC reservoir or adjust the layout (still getting some air build up). A new headgasket with ARP studs wouldn't hurt either.

I was already planning on doing the timing belt soon anyway which would include the water pump. I would've pulled the valve cover today but it started raining.

Thanks for your input!

 

Engine spun a bearing. Would explain a lot I guess....glad it happened a day or two before I was about to do hg/wp/tb

 

Oooww that sucks they do sell IAT block off plates for the manifold and re location bungs! I had issues with my IAT's reading funky, moved it before my TB and I get a steady reading now I also used a OEM sensor. Im on 13 psi but on a Cent. SC not a turbo.

 

what did you do to refinish your intake?? Looks nice

 

.99 can of flat black from Walmart haha

 

had a feeling that might be the case but turned out nice.

 

Thanks I also hit the oil cap and strut bar !

 

So.. swapped engine..new head gasket with ARP studs..new high flow 170f (~77c) thermostat..same everything else..

Idling even with some revving max temp was ~85c fans kicked in and went down to like 81c. Not bad start.

First real drive, it got up to 105c with not much boosting. Topped up the coolant a bit as it had a chance to work through, added some oil because it was filled with the car at an angle and a bit low, removed exhaust silencer and 2nd drive didn't get over 95c but that's still a bit hot. I even pulled some timing in mid-full load areas, even though my timing is already pretty conservative.

Transmission case seemed warmer than expected too but it is right behind the fan/rad.. I'm almost wondering if my turbo is fucked and heat from the journals is causing the oil to get really hot or something.. but it doesn't seem as if the turbo is way hotter than anything else, and I was barely boosting.

IAT on 2nd drive topped at like ~50c but as soon as I gave it any throttle the intercooler cooled the incoming air and dropped it by 5c in about 5 seconds which tells me the intercooler is working at least somewhat. It's like the IATs are high because the engine and head are hot making the IM hot and I even have a Honda IM gasket.. Previously after installing this gasket my IM was always cool to the touch. By previously I guess I would mean when I was driving my EG with this same motor that I just swapped in from the EG.

My downpipe is wrapped from turbo exit to oil pan. My wastegate pipe is mostly wrapped. My main intake (stainless steel) pipes have gold thermal tape at least where they go over the turbo and rad. The intercooler core also has some gold tape on it.

I had gotten a slim fan from my local speed shop a few years ago and originally installed it but it got too close to the downpipe and the wires melted.. I went back and bought another one which I didn't realize wasn't exactly the same and had a thinner motor profile. After installing it, it really seemed like a weaker fan. During the swap, I pulled apart the original and put new wires in and put it back together (reinstalling the stator into the brushes was a BITCH). I tested both fans and the old one did seem a bit more powerful when restricted and always sounded more powerful on the car, so using that fan.

I have an EGT that's already in the car, just not in the exhaust as I need an adapter to go from m18x1.5 to 1/8npt or something and I'll have to order it.

I have the throttle and IACV coolant lines bypassed and comparing a few service manuals makes things confusing but I'm going to try a different routing for that and see if it helps. Originally the hose from the water pipe went to IACV then to TB then back to small nipple on t/stat. So that's looped like that, with the small nipple on IM going to small nipple on head outlet, checked service manual for my 'teg and it only shows the oil cooler as any difference for b17, checked the b16a2 manual (99-00SiR) and it shows from water pipe to IACV to TB to nipple on IM with the other line going from small nipple on head to small nipple on t-stat - which makes more sense especially when that hose is called the bypass hose, so I'm going to make sure my routing is like that if it isn't and see if it makes any difference. Both hoses are tiny so I don't see it making a huge difference either way especially when different service manuals show different things but hey it's worth a shot.

 

The aluminum intake manifold is highly conductive and will eventually heat soak, even with thermal gaskets. I personally don't like my ECT getting much over 192F (about 89C) and it rarely does. It usually hangs out around 185-188F (85-87C). The things that worked for me to get my temps under control were:

• Using a genuine SPAL 30102029 puller fan with a shroud
• Wiring in the fan with a relay and 12 AWG power and ground wires
• Setting Hondata to turn the fan on at 185F and keep it on until I exceed 91 mph

My car is an EG coupe, so aerodynamic differences between our cars may be playing a role. I also am using a water cooled BB turbo, I have all my small coolant lines deleted, and I am running water wetter in my coolant.

 

Ya same setup in my EG didn't have issues.

 

Some service manual fun. The B17/B18A manual has two hoses I can't seem to follow (denoted by the red arrows)

The B16A2 manual calls one of the SMALLER hoses a "water bypass hose" (the one highlighted with RED) whereas generally most people refer to the bypass hose as the LARGER one highlighted in GREEN.

B18C5

B18A1 / B17A1

B16A2