Project Thread Project SC400TT

[JustenGT8]

Good luck mate, the culmination of some major effort

 

[SC400TT]

Good luck mate, the culmination of some major effort

Thanks Justen...

Ryan

 

[SC400TT]

Overheating challenges

Mates,

I have been driving my car, and it is fun...On low boost, and she has awakened once again, only better than Stage 1, except in 1 area...

Overheating!

This has been so much of an issue that I contemplated starting a new thread on it.

The AAP Fan set up, which is highly touted by MVP is what I bought, and I assumed that they not only properly designed it, but that they thoroughly tested it. While it is more than adequate for idling, it is practically useless for street driving, highway driving, more tha a few hard pulls, would never provide sufficient cooling for one lap in a road race. It is amazing how many products are "Great ideas" that are literally thrown together, instead of engineered and tested thoroughly, and sold off as the greatest thing since sliced bread!

When I started having overheating issues, I went through a myriad of different checks to see what I overlooked. Keep in mind, that I double ceramic coated all the hot side plumbing, then I wrapped it all in DEI Titanium wrap, and even double wrapped the downpipes. Everything checked out...So why was I overheating??? Plus, I was overheating on the Interstate, not on short runs around the house...In fact, as soon as I got off the interstate, and slowed down, I could literally watch the stock OEM temp needle start dropping...So I started looking at ducting, air flow, etc.

When I addressed that and I was still overheating, I noticed one fan motor had died...I replaced it, got better, but still overheating, just not as bad...

So, I looked at what I was beginning to think the culprit was...The Fan set up itself...Now keep in mind, I knew I would have to address cooling with me shoe horning (2) good sized snails and all of that turbo plumbing into the front of the engine bay...One of the reasons why I bought the AAP Fans...Supposed to be the best...the key word there is supposed...So, I decided to remove the set up this weekend after researching them quite extensively on SupraForums...I found that some people had no issues with them, although some of them had also added additional pusher fans too. In fact, when I called MVP to ask about these fans and shared my suspicions, the representative simply stated that Even Dusty uses them on his daily driven Supra, and has no issues...But, he failed to mention that Dusty also uses a Spal pusher fan in front of the condensor, which I learned from some of my research on SupraForums. So, it seemed to me that I would have to consider adding a pusher fan as well...Of course the extra draw would probably start taxing my electrical charging system, so yet another issue to consider...





First, I took out my radiator again, and looked closely at the components that made up the AAP Fan set up:

1. It has a pretty, polished aluminum shroud that is custom made to cover the complete face of the radiator so that it aids the fans in capturing all of the air coming off the radiator
2. It has (2) high speed, low profile Zirgo fans producing a combined total of approximatley 3500 cfm.
3. It has a basic wiring harness.

Looks good so far...So what is the issue? when I looked closely, it was obvious. COnsider that the OEM fans, whether electric or hydraulic, utilize a shroud to capture all the air coming off the radiator, and this routes it to the fans by simple air flow so that all of the hor air can be quickly moved aout and away fromthe radiator. If the AAP fans followed this principle, I believe they would be much more efficient. They do not.

They are essentially (2) smaller fan shrouds within a fan shroud. Each fan is approximately 11.5" in diameter, and they are a complete assembly within themselves: a fan motor, a fan blade, a wire harness, and a shroud housing each piece into a complete fan assembly. They are also approximate 1 and 3/8th of an inch deep. The actual depth of the much larger Aluminum shroud is 1.5" deep. this means the space between the (2) smaller shrouds and the face of the radiator is only approximately 1/8th"...It varies a little, and is around 2/8th" on the 9 o'clock and 3 o'clock sides if the fans. Those fan blades cannot get enough of that air removed at much of any road speed of the vehicle...So, the aluminum shroud is actually trapping the extra air it is designed to catch, and that very hot air is heat soaking the radiator.

I am trying two different sets of modifications and I will test them and let you know what I find out...





The first trial will be completed in a little while today...

1. I am installing (2) 14" low profile Flex-A-Lite fans tha pull virtually the same amperage of the 11.5" Zirgos...Only this will be a total of 4400 cfm vs 3500 cfm. These fans will not have an additional shroud, only the ones they came with in their original assembly.
2. If this works, I will custom make a shroud that will house them and work in my set up and test that because "pretty" is still very important...Just not more so that function.

Wish me luch today...I have attached somepics for you to see what I mean...Note the passenger side fan motor is chromed...That is the one I had to replace, and the chromed one is the only one I could find...ANYWHERE!!



Ryan

 

[stevieg]

Yeah that shroud is not nearly deep enough for good airflow, the new fans will work great. Make sure to check fan direction before installation as sometimes it can be tricky when they're installed

 

[cribbj]

Ryan, as you know I'm not a fan of the Zirgo's. I think their ratings are overly optimistic, and you've already experienced their poor QC. FWIW, my 550 Ferrari came with SPAL's as the OEM setup, and they're 11 years old now and still working fine.....

I hope the Flex-a-Lites will help sort the problem, but be sure to build them a proper shroud. A good shroud is the only way to assure you're pulling air through the entire radiator core. I would also include the rubber blow out flaps as we talked about, and program your ECU to turn the fans off above 50mph.

FWIW, you may not have gotten the whole story on Dusty's pusher fan. All TT Supras came stock with an aux fan in front of the condenser so that it (the condenser) would get sufficient air passing through it all the time. It's especially critical when running electric fans that cycle on/off, as without enough air, the condenser will overheat, and the pressure in the A/C system will spike and cause the high pressure switch to open and cut out the compressor. It'll start acting like it's low on freon, when in reality, it's just the condenser overheating. Then some moron may decide to top up the freon in the system, overcharging it, and you can wind up with much bigger problems (AMHIK).

I'll have a close look at the Ferrari fan/shroud setup when I get home and see how they handled the air management.

 

[stevechumo]

Ryan,
I'd suspected that you'd have overheating with your setup. How would I know? It's because I had overheating with mine. It took me too many trials and errors and finally sorted it out.

No 12" fans out there will be sufficient enough, the probem will still be around.

Fans: Gotta be at least dual puller 14" fans with the most powerful fans that you can have. Anything less than 2000 CFM for each fan won't work. Add on 1 pusher fan in front of the A/C condensor if you use the A/C. If there's no A/C, then put it directly on the radiator. Have 2 puller fans running at full speed, and the front pusher fan to kick in at around 180 F.

Fan thickness: At least 2.5". 3" or 3.5" will be alot better.
Fan shoud: It's needed.
Hood: gotta be vented hood with big hole. If the hole is to vent the hot air out, then it should be right above the turbo. I like the scoop to take in the cooler air. It cools the engine a lot better. I had tried 2 methods, and the scoop was better.
Coolant: put in 2 Water Wetter bottles and mix at least 50/50. I mixed 70 water/30 coolant.
Thermostat: Get the coolest one as you can get. I used 170 F thermostat.
The turbos are blocking the air movement in front of the engine and block the hot air from the radiator, so powerful fans really need to move them.

 

[SC400TT]

Thanks Steve. Yes, I suspected I would have to work on cooling...But I did not expect the AAP Fans to be such a loser here. They seem to work fine for N/A and Supercharged applications, but for turboed cars, they seem to not work well at all...too much extra heat to deal with.

These things I need to do before I come up with a final determination.

• Connect up the climate control unit, jack up the car again, idle the engine and run the heaterto make sure the air is burped out of the complete system, including the heater core.
• Make the modifications necessary to install the under panels...The lower louvered one as well as the under panel...I know these are critical for directing air flow through the engine bay.

My FMIC is big enough that it sits a little low for the louvered under panel, so I have to make a spacer to fit it, and reangle it so that the louvers will direct air upwards as Toyota originally designed. Then I can connect the other panel...the one that blocks the oil filter...These should help to duct the air properly...

I have connected the new 14" electric fans, and I have tested them...I was ok on the Interstate, but it was getting dark, and I have not connected the lights, so I could only make4 a few mile run...But a significant improvement over the AAP Fans.

I am holding off from installing a 160 degree TRD thermostat, but I am considering ordering one and installing it as well.

I have read about Water Wetter, Royal Purple, etc...But I am concerned about the potential for them to interact with some coolants and create a greasy sludge that coats the complete cooling system. So, I want to hold off for now.

I will update as I progress.

Ryan

 

[SC400TT]

Thanks John.

I do not believe the Zirgos flow anymore air than any other equivalent electric fan. They are more than likely all made by a few companies...especially the components that make them up, especially the electric motors.

Although I may build a shroud, I am not sure I can build them the way I would like to...I simply do not have the room for a thick shroud. I will have to get creative on how to integrate and fabricate the flaps...again, due to lack of room.

I will make sure they are programmed to turn of at higher speed.

Ryan

Ryan, as you know I'm not a fan of the Zirgo's. I think their ratings are overly optimistic, and you've already experienced their poor QC. FWIW, my 550 Ferrari came with SPAL's as the OEM setup, and they're 11 years old now and still working fine.....

I hope the Flex-a-Lites will help sort the problem, but be sure to build them a proper shroud. A good shroud is the only way to assure you're pulling air through the entire radiator core. I would also include the rubber blow out flaps as we talked about, and program your ECU to turn the fans off above 50mph.

FWIW, you may not have gotten the whole story on Dusty's pusher fan. All TT Supras came stock with an aux fan in front of the condenser so that it (the condenser) would get sufficient air passing through it all the time. It's especially critical when running electric fans that cycle on/off, as without enough air, the condenser will overheat, and the pressure in the A/C system will spike and cause the high pressure switch to open and cut out the compressor. It'll start acting like it's low on freon, when in reality, it's just the condenser overheating. Then some moron may decide to top up the freon in the system, overcharging it, and you can wind up with much bigger problems (AMHIK).

I'll have a close look at the Ferrari fan/shroud setup when I get home and see how they handled the air management.

 

[JBrady]

Ok, first of all the original "shroud" was no such thing. The fans protruded to the core and the "shroud" surrounded them and was actually a air BLOCKER. The only flow you had was through the fan holes so you only had two 12" round holes for flow. The new setup without a shroud is much better as air can now flow through the entire radiator.

The new 14" fans should work better especially without the previous blockage. They also have back curved blades which should be quieter even though they are bigger.

A shroud will only help if you can create a plenum space for the fans to create a vacuum in. With the fans directly attached to the core a shroud will just block flow. Flaps on a shroud allow air to push through the core and not be restricted to the area left by a shroud. If you have no room for a shroud you have no need for shroud flaps.

As we discussed the DUCTING from the front of the car to the core is NEEDED to ram the air through the core as the vehicle speed increases. At low speeds and low to no load on the engine the fans work to keep things reasonable. At higher speed and load the engine creates more heat to deal with. This is where the ram air effect will flow more air than fans can IF you have proper ducting. This is why Mr. Cribb suggests turning off the fans above 50mph.

Proper ducting takes the air that enters the front of the car and SEALS it into a focused flow through the rad core. With a intercooler and air con condenser rad to deal with you need to SEAL the air flow from escaping around the radiator. So, from the car front build WALLS around the cores creating a tunnel for the air to be forced through. If your intercooler blocks and or heats the air too much you may need auxillary radiator capacity. Your initial highway runs are promising but this is an engineering exercise... some trial and error should be expected.

If you decide to get real fancy you can engineer some under car aero aids that could pull air out of the engine compartment reducing underhood heat and improving the air flow through the rad cores. Fancy and tricky are good words here.

 

[JBrady]

Some ducting pictures for ideas:

 

[JBrady]

A pic for the "fancy" and "tricky" part.

 

[XR8tt]

Hmm ?? I think going to larger radiator would be far easier...
Larger header / expansion tank maybe ??
An I.C out the front loses air under the car..
Which doesn't help cooling radiator..
I have found a J guard on it's side prevents air escaping from I.C to under car..
An engine guard under car helps draw air through whilst driving also...
Have found if it requires fans to cool at speed ???
Then there's something not right or officiant in cooling system...

 

[BlackUZZ31]

I had an interesting issue with my Cressida wagon when I first got it running...

I tend to get a bit fussy when i work on cars, planing all the wiring out, had a massive custom 3inch thick core radiator made, two 12 inch fans, Toyota red coolent...

no matter what I did... thermostats, ducting, flushing the radiator... the car would run hot, even with the heater on it would still start to cook...

after weeks of stuffing around I pulled the radiator out...

... and found the wiring diagrams i had lost.. slid down between the radiator and the A/C heat exchanger..

 

[SC400TT]

John,

I appreciate you commenting and offering some excellent suggestions....

After our conversation, I decided to start working up ideas for ducting air...I believe I want to be sure not to overdo it, as I believe at higher speeds this can add lift to the front end and if correct, that would not suffice. Please share your thoughts on that.

First, I looked at the stock OEM under panels, which I have yet to re-install. Last night I fitted them up to their original positions and I saw clearly that this is at least part of the problem. The front under panels consist of (2) separate pieces. The front one is connected to the front of the bottom of the bumper and then connects to the bottom of the radiator/condenser housing. It is also angled and louvered so that it will direct air up and into the radiator/condenser. That should help with the issue on the highway. But, I have a problem...my big FMIC sits about 3/4" lower than the bottom of the stock bumper cover. So, the panel cannot mate up to it as is. If you all recall, I molded a FRP lip onto the front bumper...that happens to sit approximately 3/4" lower than the stock bumper, or parallel to the bottom of the FMIC. This is good. I am having a custom piece of 3/4" plastic fabricated to fill that space and act as a mounting surface plus a spacer so that the OEM panel will fit properly and direct air up into the engine bay. I am also having a similar piece made for the back of it as well so that I can adjust for the correct angle.

Second, the main underside panel mates form the edge of the first panel and continues to cover the whole engine compartment form the bottom. This would force air rushing in to flow through the whole engine bay, and out the back. I figure this is playing a large role in overheating because the air is currently not flowing in the correct direction. In fact, the air is probably not flowing into the engine bay other than what the fans blow. I will see how this helps next.

Keep in mind that I have vented my hood...I will just remove the machine guns form the Aston vents, as they are probably blocking the air flowing out...LOL...

Agreed John...not a shroud at all...the AAP Fan set up.

I like the "fancy" with the Ferrari...I have thought of that, but the second pic looks better as that Carl shows a vent out area from the engine bay.

We will see what happens with this, and I will keep you all updated...

Ryan

Ok, first of all the original "shroud" was no such thing. The fans protruded to the core and the "shroud" surrounded them and was actually a air BLOCKER. The only flow you had was through the fan holes so you only had two 12" round holes for flow. The new setup without a shroud is much better as air can now flow through the entire radiator.

The new 14" fans should work better especially without the previous blockage. They also have back curved blades which should be quieter even though they are bigger.

A shroud will only help if you can create a plenum space for the fans to create a vacuum in. With the fans directly attached to the core a shroud will just block flow. Flaps on a shroud allow air to push through the core and not be restricted to the area left by a shroud. If you have no room for a shroud you have no need for shroud flaps.

As we discussed the DUCTING from the front of the car to the core is NEEDED to ram the air through the core as the vehicle speed increases. At low speeds and low to no load on the engine the fans work to keep things reasonable. At higher speed and load the engine creates more heat to deal with. This is where the ram air effect will flow more air than fans can IF you have proper ducting. This is why Mr. Cribb suggests turning off the fans above 50mph.

Proper ducting takes the air that enters the front of the car and SEALS it into a focused flow through the rad core. With a intercooler and air con condenser rad to deal with you need to SEAL the air flow from escaping around the radiator. So, from the car front build WALLS around the cores creating a tunnel for the air to be forced through. If your intercooler blocks and or heats the air too much you may need auxillary radiator capacity. Your initial highway runs are promising but this is an engineering exercise... some trial and error should be expected.

If you decide to get real fancy you can engineer some under car aero aids that could pull air out of the engine compartment reducing underhood heat and improving the air flow through the rad cores. Fancy and tricky are good words here.

 

[spf_lexus]

Interesting discussion on shrouds. I have been running dual 14" pullers w/o any kind of shroud and on 100 degree days sitting in traffic, I never see the needl rise above the half way mark.

SC400TT, im sure your DB hood vents will help facilitate flow through the rad, acting like a drop vent hood.

 

[XR8tt]

Believe it or not this was covered in Corky Bells book...
Yep some seem to get away with cooling issues ..

Like I preach to my Mrs & kids...
Overheating is far far worse than running out of petrol !!!

 

[stevechumo]

.....
Second, the main underside panel mates form the edge of the first panel and continues to cover the whole engine compartment form the bottom. This would force air rushing in to flow through the whole engine bay, and out the back. I figure this is playing a large role in overheating because the air is currently not flowing in the correct direction. In fact, the air is probably not flowing into the engine bay other than what the fans blow. I will see how this helps next.

Keep in mind that I have vented my hood...I will just remove the machine guns form the Aston vents, as they are probably blocking the air flowing out...LOL...

Ryan

The hot air is blocked within the engine and causing heat soak. Venting it out isn't enough. If you can push it out, it'll help big time. On my setup, I had thought about install a small e-fan at the bottom and between the radiator and the engine. This fan will suck in the air from the ground and blow the air up. It'll work similar like panel ducting.

 

[SC400TT]

Interesting discussion on shrouds. I have been running dual 14" pullers w/o any kind of shroud and on 100 degree days sitting in traffic, I never see the needl rise above the half way mark.

SC400TT, im sure your DB hood vents will help facilitate flow through the rad, acting like a drop vent hood.

My overheating is while driving down the interstate at 50+ mph...Air should escape through those vents pretty well...

Believe it or not this was covered in Corky Bells book...
Yep some seem to get away with cooling issues ..

Like I preach to my Mrs & kids...
Overheating is far far worse than running out of petrol !!!

Yep, I am reviewing that book as well...It has stopped collecting dust in the library...

The hot air is blocked within the engine and causing heat soak. Venting it out isn't enough. If you can push it out, it'll help big time. On my setup, I had thought about install a small e-fan at the bottom and between the radiator and the engine. This fan will suck in the air from the ground and blow the air up. It'll work similar like panel ducting.

Steve, The air is not totally blocked, in fact, quite a bit gets around the plumbing...The turbos aren't actually blocking the air flow to the engine, it is some of the plumbing, mainly on the passenger side. On the driver's side, it is pretty much a straight shot from the fan to the engine. I may have to dcut the air further than that, and I am looking itno it. But, I am basically trial and erroring it 1 step at a time until I get it conquered.

 

[spf_lexus]

what kind of radiaor are you using and how old? When i bought my 92 sc, it idled cool but at freeway speeds, it would overheat. Turns out the stock rad was plugged up with scale.

 

[SC400TT]

what kind of radiaor are you using and how old? When i bought my 92 sc, it idled cool but at freeway speeds, it would overheat. Turns out the stock rad was plugged up with scale.

I have a new Koyo All aluminum radiator...It is one of the best out there...

Ryan