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Help me understand heat soak cure


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A lot of people refer to timing being pulled due to heat soak. Members have said that the OEM intercooler is adequate for normal street driving while other members have upgraded to larger IC's and said they work better.

 

Is heat soak solved by correcting the IC or do you need to upgrade the radiator also? We've seen some great looking radiator replacements with dual fans etc. and larger metal expansion tanks.

 

Do these replacement parts solve the heat soap issue or just reduce high temps?

 

BTW, in the summer months my area can stay in the high 90's for weeks at a time

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I live in sometimes continual 90 degree weather also, and my car has never budged above normal on the water temperature, even while once stuck in a 90 min traffic jam w/ ambient about 90, and that was with the stock supercharger, 550 rwhp, and stock intercooler. I know have 700 rwhp and a larger intercooler and I have lately installed an actual water temp guage just to be on the safe side (still have stock radiator). To answer your question, i personally do not think you need a larger radiator, but a larger intercooler can only help regarding the 'heak soak'. However.....if your car is bone stock, even though it would help, im not sure if you actually 'need' a larger intercooler, so back to everyone elses take on this?

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Dactyl has researched this issue to the 'nth degree through datalogging of stock cars up to highly modified cars. My understanding is these supercharged cars, even in stock setup, will heat soak under persistent spirited driving conditions in a relatively short time depending on conditions. My understanding is the heat exchanger alone will help delay heat soak, but the radiator/heat exchanger combination is really the only complete remedy.

 

I'm sure Dactyl will chime in and offer his wisdom.

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Even on a cool November night a Camaro raced me repeatedly until he did eventually win due to my heatsoak. I fixed that soon after with 'Dactyl's' Revan Racing dual pass dual fan heat exchanger:

 

1IMG_1379.jpg

IMG_1434.jpg

 

 

I think Secondo's example above is excellent and demonstrative of the heat soak issues with our cars. Regardless of a stock blower with a stock tune or an aftermarket tune or an aftermarket blower and tune these cars get heat soaked. Now how do you define 'Heat Soak'? Heat soak is basically when the the ECU begins to retard timing and spark due to certain parameters reached within the program of the ECU, those parameters being Engine Coolant Temperature, Cylinder Head Temperature and IAT2 or after supercharger temperatures to name a few.

 

Generally speaking IAT2 is the culprit for 'Heat Soak Symptoms'

 

On a bone stock GT500 Ford programs the ECU to reduce timing and spark at 100 degrees IAT2. It doesn't take a whole lot to get to 100 degrees. In fact, cruising down the highway with an aftermarket or stock heat exchanger you will generally average over 100 degrees IAT2.

 

Aftermarket Tuners like Jon Lund will generally raise the IAT2 to about 130 to 140 degrees and then begin spark and timing retard. The other function of raising these levels even higher is A/F ratio and timing.

 

I have data logged numerous vehicles. Bone Stock, Slightly Modified to totally modified.

 

The other function of reducing temperatures is fluid, capacity and flow.

 

Fluid- Stock the system comes with FoMoCo Gold Anti-Freeze. Some like to refer to it as coolant. It's not coolant, it's anti-freeze. You will notice in your own vehicles that changing to 10-20% coolant and the balance in Water and Water Wetter temperatures will reduce. Better yet, all water and Water Wetter.

 

Capacity-The stock intercooling system is insufficient. I strongly recommend you consider an after market supercharger reservoir. This can add upwards of 3 quarts of fluid to the system which is a big help. You achieve better heat dissipation with more fluid. Shelby will soon be releasing new engine bay reservoirs that are second to none.

 

Flow-The inlet and outlet of the stock supercharger reservoir (Degas Bottle) actually has metal reducers that restrict the flow and cause back pressure to the intercooler which further increases the temperature of the fluid in the intercooler. Better flow is achieved with a different reservoir which also gives you added capacity as well.

 

Even with all of the aforementioned improvements the Shelby Heat Exchanger changed everything with respect t reducing IAT2's. There are a couple of reasons for the improved IAT2's. Heat Exchanger Core and Puller Fans.

 

Core-The Heat Exchanger Core is a NASCAR proprietary core only available to C&R Racing, the manufacturer of the Shelby Heat Exchanger, Radiator and Engine Bay Reservoirs. There is not a core being used in the aftermarket with as much research and development. The cores being used are the same cores as used by Ford for the FR500 Series race cars and C&R makes those too.

 

Puller Fans-The fans and complete system were designed to fit and replace the factory unit without having to move anything. It fits up in front of the condenser. The puller fans work to pull the heat from the heat exchanger core very similar to when your fan turns on with the radiator. One difference. I like to run the fans at key on. This way the temperatures in the intercooling system are constantly being reduced.

 

Many people have installed the C&R product prior to the licensing agreement and arrangement with Shelby for these parts. It doesn't require a new tune however you will find as have many of the people that have installed the product how much longer the power is available because we have effectively taken higher IAT2's out of the equation.

 

As for the radiator, I like to look at it like insurance. It more than doubles the capacity of the stock radiator and more efficiently and effectively cools the cylinder heads and keeps the engine running much cooler, yes, even for the daily driver. A 160 degree or 180 degree thermostat helps as well. The sooner the TSTAT opens the sooner you begin to use the cooling properties of the radiator.

 

Let me know if you have any other questions. I'll be happy to answer them.

 

VC

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:happy feet: Thanks! It was a no-brainer!

 

You have one or two yourself, no? :happy feet:

 

Sweet rides!! :rockon:

 

Oh you bet I do. A must do mod if you ask me.

 

How's your Shelby running now that you have good weather to enjoy her?

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Thank you for such a clear explanation. To have the fans turn on at key on is that a tuning function or a hardwiring issue?

 

 

Actually, what I do is trigger the fan relays with a wire tap off of the water pump voltage wire (white with red stripe)

 

Then I by-pass the ECU control by pulling the relay control unit and placing a 20 AMP mini fuse with slightly twisted blades. Then the pump and the fans all come on at key on.

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Oh you bet I do. A must do mod if you ask me.

 

How's your Shelby running now that you have good weather to enjoy her?

A must do, I agree.

 

I love the car, the best Mustang built so far! What great feeling it is to finally take it out after a long winter.

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Actually, what I do is trigger the fan relays with a wire tap off of the water pump voltage wire (white with red stripe)

 

Then I by-pass the ECU control by pulling the relay control unit and placing a 20 AMP mini fuse with slightly twisted blades. Then the pump and the fans all come on at key on.

 

How is the fan noise?

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I think Secondo's example above is excellent and demonstrative of the heat soak issues with our cars. Regardless of a stock blower with a stock tune or an aftermarket tune or an aftermarket blower and tune these cars get heat soaked. Now how do you define 'Heat Soak'? Heat soak is basically when the the ECU begins to retard timing and spark due to certain parameters reached within the program of the ECU, those parameters being Engine Coolant Temperature, Cylinder Head Temperature and IAT2 or after supercharger temperatures to name a few.

 

Generally speaking IAT2 is the culprit for 'Heat Soak Symptoms'

 

On a bone stock GT500 Ford programs the ECU to reduce timing and spark at 100 degrees IAT2. It doesn't take a whole lot to get to 100 degrees. In fact, cruising down the highway with an aftermarket or stock heat exchanger you will generally average over 100 degrees IAT2.

 

Aftermarket Tuners like Jon Lund will generally raise the IAT2 to about 130 to 140 degrees and then begin spark and timing retard. The other function of raising these levels even higher is A/F ratio and timing.

 

I have data logged numerous vehicles. Bone Stock, Slightly Modified to totally modified.

 

The other function of reducing temperatures is fluid, capacity and flow.

 

Fluid- Stock the system comes with FoMoCo Gold Anti-Freeze. Some like to refer to it as coolant. It's not coolant, it's anti-freeze. You will notice in your own vehicles that changing to 10-20% coolant and the balance in Water and Water Wetter temperatures will reduce. Better yet, all water and Water Wetter.

 

Capacity-The stock intercooling system is insufficient. I strongly recommend you consider an after market supercharger reservoir. This can add upwards of 3 quarts of fluid to the system which is a big help. You achieve better heat dissipation with more fluid. Shelby will soon be releasing new engine bay reservoirs that are second to none.

 

Flow-The inlet and outlet of the stock supercharger reservoir (Degas Bottle) actually has metal reducers that restrict the flow and cause back pressure to the intercooler which further increases the temperature of the fluid in the intercooler. Better flow is achieved with a different reservoir which also gives you added capacity as well.

 

Even with all of the aforementioned improvements the Shelby Heat Exchanger changed everything with respect t reducing IAT2's. There are a couple of reasons for the improved IAT2's. Heat Exchanger Core and Puller Fans.

 

Core-The Heat Exchanger Core is a NASCAR proprietary core only available to C&R Racing, the manufacturer of the Shelby Heat Exchanger, Radiator and Engine Bay Reservoirs. There is not a core being used in the aftermarket with as much research and development. The cores being used are the same cores as used by Ford for the FR500 Series race cars and C&R makes those too.

 

Puller Fans-The fans and complete system were designed to fit and replace the factory unit without having to move anything. It fits up in front of the condenser. The puller fans work to pull the heat from the heat exchanger core very similar to when your fan turns on with the radiator. One difference. I like to run the fans at key on. This way the temperatures in the intercooling system are constantly being reduced.

 

Many people have installed the C&R product prior to the licensing agreement and arrangement with Shelby for these parts. It doesn't require a new tune however you will find as have many of the people that have installed the product how much longer the power is available because we have effectively taken higher IAT2's out of the equation.

 

As for the radiator, I like to look at it like insurance. It more than doubles the capacity of the stock radiator and more efficiently and effectively cools the cylinder heads and keeps the engine running much cooler, yes, even for the daily driver. A 160 degree or 180 degree thermostat helps as well. The sooner the TSTAT opens the sooner you begin to use the cooling properties of the radiator.

 

Let me know if you have any other questions. I'll be happy to answer them.

 

VC

 

Couple more questions for inquiring minds on a budget:

 

If you go with just the heat exchanger without upgrading the resvoir, is that alone sufficient to drastically reduce IAT2s given the greater fluid capacity and efficient core of the HE?

 

Will the HE indirectly reduce engine temps too; thus delaying spark and timing retard due to high coolant and cylinder head temps?

 

If you can only do one piece at a time, will you experience a notable difference with just the HE or should you wait to do the whole shebang at once? I'm thinking of going the incremental route over time with HE first, radiator second, resevoir tanks third. If I do it this way what changes can I expect at each step?

 

Thanks,

CSL

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Couple more questions for inquiring minds on a budget:

 

If you go with just the heat exchanger without upgrading the resvoir, is that alone sufficient to drastically reduce IAT2s given the greater fluid capacity and efficient core of the HE?

 

Will the HE indirectly reduce engine temps too; thus delaying spark and timing retard due to high coolant and cylinder head temps?

 

If you can only do one piece at a time, will you experience a notable difference with just the HE or should you wait to do the whole shebang at once? I'm thinking of going the incremental route over time with HE first, radiator second, resevoir tanks third. If I do it this way what changes can I expect at each step?

 

Thanks,

CSL

 

Do radiator & heat exchanger at the same time and save on labor cost.......unless you are a DIY.

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Couple more questions for inquiring minds on a budget:

 

If you go with just the heat exchanger without upgrading the resvoir, is that alone sufficient to drastically reduce IAT2s given the greater fluid capacity and efficient core of the HE?

 

Will the HE indirectly reduce engine temps too; thus delaying spark and timing retard due to high coolant and cylinder head temps?

 

If you can only do one piece at a time, will you experience a notable difference with just the HE or should you wait to do the whole shebang at once? I'm thinking of going the incremental route over time with HE first, radiator second, resevoir tanks third. If I do it this way what changes can I expect at each step?

 

Thanks,

CSL

 

Answer to the first question. Absolutely. On a GT500 with the stock reservoir at Sebring running a TVS with a 2.6 pulley the car would begin to pull timing at 140 degrees. It took roughly 20 minutes of hard driving to achieve that temperature. Mind you, the guy driving the car also had a full Griggs Suspension and was on the power a lot. But we did notice that the car was getting heat soaked due to the reservoir size and the inlets and outlets of the stock Degas Bottle.

 

The HE can reduce engine temps to a small degree. The addition of the fans at 1,400 plus CFM blowing through the condenser into the bottom of the radiator which rarely gets air does have its benefits.

 

HE first, Yes. Supercharger reservoir second, and then the radiator. The radiator is really beneficial in keeping temps down if you drive with some spirit and it gets hot quick. The other factor is fluid, 10-20% coolant and the rest water will help dissipate heat.

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How is the fan noise?

I was quite surprised that the twin SPAL fans on the C&R were that quiet. You can barely hear them at a stop light with the windows open. Not at all while driving, thats for sure.

 

I just finished my C&R HE install this morning. All went smooth with the instructions that Van sent and his assistance was first rate. Thanks Bud!

 

I did notice that my stock HE was full bug carnage, and then some. The upper rad was afflicted with the same bug guts. I purchased some large hole plastic screen from the local hardware store to cover the HE and upper rad to prevent a similar bug occurence from plugging up the fins.

 

I tested the screen with a hair dryer first to test air flow and it passed. When I tested the C&R fans a rag immediatly got sucked up to the fins. I don't think airflow is impeded at all. Plus the black screen darkened the silver HE fins (good). I like the over all look and function with this Bug Off mod.

 

A couple photos.

Picture705.jpg

HE and upper rad covered.

Picture706.jpg

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I was quite surprised that the twin SPAL fans on the C&R were that quiet. You can barely hear them at a stop light with the windows open. Not at all while driving, thats for sure.

 

I just finished my C&R HE install this morning. All went smooth with the instructions that Van sent and his assistance was first rate. Thanks Bud!

 

I did notice that my stock HE was full bug carnage, and then some. The upper rad was afflicted with the same bug guts. I purchased some large hole plastic screen from the local hardware store to cover the HE and upper rad to prevent a similar bug occurence from plugging up the fins.

 

I tested the screen with a hair dryer first to test air flow and it passed. When I tested the C&R fans a rag immediatly got sucked up to the fins. I don't think airflow is impeded at all. Plus the black screen darkened the silver HE fins (good). I like the over all look and function with this Bug Off mod.

 

A couple photos.

Picture705.jpg

HE and upper rad covered.

Picture706.jpg

 

enormous is a perfect example of a guy that wanted to upgrade his heat exchanger. Perhaps Norm would like to tell us how the car feels power wise now with just a swap of the heat exchanger. Norm?

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Before Christmas I noticed Vans post on the C&R HE sporting the Twin SPAL fans. Upgrading the HE was on my list of mods since recieving my Shelby in Spril of 08, and I was glad that I waited. Unfortunatly I was not able to get into the first group buy. So I decided to save a little bit here and there to get the best, and do it right the first time.

 

I spent a good amount of time today driving my stage II (TVS later) Shelby much harder than I did in the past. I kept on putting my right foot into it to see if I could notice any onset of heat soak like before. Nada, nothing, just full power. When hot last summer I certainly noticed the power loss on the street when timing was pulled.

 

Heat soak is now a thing of the past. Every time I put my right foot into it, I was rewarded with full power. Am I happy? you bet I am. Would I do it again? yes on that one too.

 

The install was rewarding as well. I only got to use one hour a day for the install due to scheduling . However I did spent extra time on the wiring, covering every wire with black plastic protector for a discrete routing, and a clean look. The screen covering was my idea.

 

Best of all I learned something new about my car.

 

Also, Van was a first class vender all the way. Never once did I have to wait for a reply. His communication was always quick and timely and the transaction went very smooth.

Thanks Van!

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Before Christmas I noticed Vans post on the C&R HE sporting the Twin SPAL fans. Upgrading the HE was on my list of mods since recieving my Shelby in Spril of 08, and I was glad that I waited. Unfortunatly I was not able to get into the first group buy. So I decided to save a little bit here and there to get the best, and do it right the first time.

 

I spent a good amount of time today driving my stage II (TVS later) Shelby much harder than I did in the past. I kept on putting my right foot into it to see if I could notice any onset of heat soak like before. Nada, nothing, just full power. When hot last summer I certainly noticed the power loss on the street when timing was pulled.

 

Heat soak is now a thing of the past. Every time I put my right foot into it, I was rewarded with full power. Am I happy? you bet I am. Would I do it again? yes on that one too.

 

The install was rewarding as well. I only got to use one hour a day for the install due to scheduling . However I did spent extra time on the wiring, covering every wire with black plastic protector for a discrete routing, and a clean look. The screen covering was my idea.

 

Best of all I learned something new about my car.

 

Also, Van was a first class vender all the way. Never once did I have to wait for a reply. His communication was always quick and timely and the transaction went very smooth.

Thanks Van!

 

God, I wish I had the skills and nerve to dive into a project like you guys have done. Could you estimate for me how many hours it would take a skilled mechanic to replace the radiator and H/E as you have done? BTW, thanks for such great information.

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God, I wish I had the skills and nerve to dive into a project like you guys have done. Could you estimate for me how many hours it would take a skilled mechanic to replace the radiator and H/E as you have done? BTW, thanks for such great information.

 

 

A skilled mechanic should be able to extract and install all of the products including wiring the relays for the heat exchanger in 4 to 4.5 hours. 5 Hours Max. If they take longer than that, they are screwing around.

 

VC

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God, I wish I had the skills and nerve to dive into a project like you guys have done. Could you estimate for me how many hours it would take a skilled mechanic to replace the radiator and H/E as you have done? BTW, thanks for such great information.

It's much easier than it looks. Give it a try, it's worth putting your personal touch into your Shelby.

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  • 1 year later...

Folks,

 

I know I'm about a year and a half or maybe two years late on this, but then I only just recently acquired my '08 GT 500. Stumbled upon this thread and well, guess I should be concerned, right?

 

Will be using it for daily driving once I get it registered in Pennsylvania, and the friggin' rain stops....

 

So, I guess the ultimate question, is this a big concern for me...and I'd be driving in such places as NJ, where the traffic can really be lousy. Appreciate any thoughts.

 

 

Thanks,

 

 

chris

:banghead: :

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Heat soak is unrelated to engine operating temperature in day to day driving. All that happens with heat soak is you lose power. Assuming you are not racing on the way to work, you do not need anything additional on your car. I have a full Revan Racing/Shelby cooling system upgrade on my SGT and it makes a BIG difference on the track but, other than that (I do not do or condone street racing), you are good to go as is. If you choose to upgrade, the good news is that you can do no harm and, for my money, the Revan Racing/Shelby set up is the best thing out there. It is not cheap but it is effective. Good luck and welcome.

 

Jim

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