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Stock Mount Intercooler Options....and why is Petit so $$$?

Old 01-31-19, 01:46 PM
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IMO, I can' see the XSPower IC you have as being very efficient in heat transfer and looks like a large heat soak sink. The metal is way to thick on the end caps to transfer off absorbed heat after heat soak. The bar design also looks like very thick metal (poor for heat transfer), are very thick in height, and the transfer metal fins rows are small(less surface area). The air flow through this can't be very good given the height of the bars, their flat face( I know many IC's are this way), the number of rows, and the small metal fin transfer slots(not a lot of air going through). With less air flow through it, the efficiency will suffer a lot. The heat transfer of any radiator/IC design is mainly based on the metal thickness of the interface(thinner the better, within reason), the overall surface area for heat transfer(overall length, depth, and number of rows for heat exchange), and the amount (volume and velocity of air) of the transfer agents on each side(in this case air to air). Little air flow through any IC no matter how big or how many rows means poor relative efficiency. In this case, a small IC + suboptimal design=maybe you should reconsider. Sorry if this offends you, but I am just trying to help.
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Old 01-31-19, 08:13 PM
  #27  
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For more understanding of how a vmount works, I found this article to be helpful:

https://motoiq.com/project-rotary-fd...d-intercooler/

I've actually gone to the track with a modified large SR Motorsports SMIC. The first time, it heat soaked so badly it wouldn't boost anymore, IAT was 65 Celsius and UP! The second time, I had a vented hood and wrapped the IC and piping with DEI heat reflective tape. This time, as long as I started the car up from somewhat cool and kept moving, IAT would stay below 45C (still hot!). But I had to keep moving and accelerating, pulling hot air out of the hood and fresh air from the front. As soon as I slowed down or drove on the street, 55C and up, which is quite dangerous.

Am definitely going vmount soon.
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Old 01-31-19, 11:39 PM
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For my setup with the modified IC, the ducting, end tanks and charge piping will be insulated to help avoid bad heat soak. The climate where I am at is much cooler than a lot of other places, the car will rarely see outside temps over 25C. Is the set up ideal - no. Is any SMIC ideal, having to draw air through a restrictive duct into a hot section of the engine bay - no. When the time comes and I move towards a single turbo, I'll be going to a vmount. While working with my IC, I found out the end tanks are cast and not sheet, giving it the weight that it has.
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Old 02-01-19, 09:44 AM
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I have the Petit CC3 and most often times its great. Except when its not. When I go to areas 100 degree plus it heat soaks pretty quick and takes forever to cool down even just cruising. I think the duct needs an extension which would help draw in more air, also I am not using the fan to help pull air in which would also help so that's my fault. Overall it works well and I do like it. But I still am considering a V mount soon so I can hopefully not have to worry about the heat soak issue as much. We'll see
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Old 02-01-19, 09:48 AM
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Originally Posted by silverTRD View Post
I have the Petit CC3 and most often times its great. Except when its not. When I go to areas 100 degree plus it heat soaks pretty quick and takes forever to cool down even just cruising. I think the duct needs an extension which would help draw in more air, also I am not using the fan to help pull air in which would also help so that's my fault. Overall it works well and I do like it. But I still am considering a V mount soon so I can hopefully not have to worry about the heat soak issue as much. We'll see
hi neighbor
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Old 02-01-19, 01:11 PM
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Originally Posted by mkiv98 View Post
...and wrapped the IC and piping with DEI heat reflective tape...
Ineffective use of reflective foil...Some sort of thermal barrier coating to prevent convection would be more appropriate.

https://www.greenteg.com/heat-flux-s...heat-transfer/
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Old 02-01-19, 01:35 PM
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Pre-IC WI/AI...it’s not a silver bullet either, just throwing that out as one option to those worried about heat-soak but not wanting to V-mount.
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Old 02-01-19, 05:48 PM
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Originally Posted by silverTRD View Post
I have the Petit CC3 and most often times its great. Except when its not. When I go to areas 100 degree plus it heat soaks pretty quick and takes forever to cool down even just cruising. I think the duct needs an extension which would help draw in more air, also I am not using the fan to help pull air in which would also help so that's my fault. Overall it works well and I do like it. But I still am considering a V mount soon so I can hopefully not have to worry about the heat soak issue as much. We'll see
Yeah I think that's a fairly big opportunity for improvement.

Thinking about the geometry for the area, the duct opening at the front is somewhat small. Although it's plenty large to handle the flow volume, the opening being small at the front and expanding to a LARGE opening where it interfaces with the IC is terrible if you're going to rely on vehicle movement as a way to push air through the IC. It's basically acting as a reverse velocity stack. Now, if you have the fan PULLING air through the IC then I would think the geometry of the duct matters very little as long as the opening at the front is sufficiently large to allow the volume of air through.
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Old 02-01-19, 10:43 PM
  #34  
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Also, another option is an FMIC. And when I say option, I mean a properly ducted one.

A properly ducted FMIC can work great, assuming ducting is proper and the radiator is getting air too. It seems like FMICs got a bad name because people don't know how to do ductwork. An FMIC frees up a ton of space in the engine bay which has other benefits as well.
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Old 02-02-19, 04:31 AM
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Originally Posted by mkiv98 View Post
For more understanding of how a vmount works, I found this article to be helpful:

https://motoiq.com/project-rotary-fd...d-intercooler/

I've actually gone to the track with a modified large SR Motorsports SMIC. The first time, it heat soaked so badly it wouldn't boost anymore, IAT was 65 Celsius and UP! The second time, I had a vented hood and wrapped the IC and piping with DEI heat reflective tape. This time, as long as I started the car up from somewhat cool and kept moving, IAT would stay below 45C (still hot!). But I had to keep moving and accelerating, pulling hot air out of the hood and fresh air from the front. As soon as I slowed down or drove on the street, 55C and up, which is quite dangerous.

Am definitely going vmount soon.
what vented hood did you conduct the test with?
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Old 02-02-19, 10:02 AM
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Originally Posted by mkiv98 View Post
hi neighbor
hey buddy
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Old 02-04-19, 02:12 AM
  #37  
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Originally Posted by kensin View Post
what vented hood did you conduct the test with?
I used the feed hood. I would imagine the more aggressive hoods like scoot would be better, but I also like it kind of subtle. Also, you know what kind of hood I have dude lol
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Old 02-05-19, 04:04 AM
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Originally Posted by mkiv98 View Post
I used the feed hood. I would imagine the more aggressive hoods like scoot would be better, but I also like it kind of subtle. Also, you know what kind of hood I have dude lol
totally slipped my mind lol
the temp reading/difference could differ from say a... RE-A AD9 hood since the vents are much larger and more direct above the front heat transfer area
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Old 02-05-19, 11:37 AM
  #39  
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Originally Posted by silverTRD View Post
I have the Petit CC3 and most often times its great. Except when its not. When I go to areas 100 degree plus it heat soaks pretty quick and takes forever to cool down even just cruising. I think the duct needs an extension which would help draw in more air, also I am not using the fan to help pull air in which would also help so that's my fault. Overall it works well and I do like it. But I still am considering a V mount soon so I can hopefully not have to worry about the heat soak issue as much. We'll see
Originally Posted by ItalynStylion View Post
Yeah I think that's a fairly big opportunity for improvement.

Thinking about the geometry for the area, the duct opening at the front is somewhat small. Although it's plenty large to handle the flow volume, the opening being small at the front and expanding to a LARGE opening where it interfaces with the IC is terrible if you're going to rely on vehicle movement as a way to push air through the IC. It's basically acting as a reverse velocity stack. Now, if you have the fan PULLING air through the IC then I would think the geometry of the duct matters very little as long as the opening at the front is sufficiently large to allow the volume of air through.
I believe the thinking is totally correct here, but a puller fan is terribly inefficient and would be overcome even at moderate vehicle speeds if you can pressurize the duct with a proper duct inlet like silver TRD suggests.

I've done some testing on a stock setup and found dramatic improvement by extending the duct inlet into the front bumper opening. Doing this claims some of the flow that is normally reserved for the radiator alone, similar to a VMIC setup. If you look at most SMIC's duct entrance and placement it is hard to imagine it getting any air volume or pressure from the bumper opening.

The SMIC is not the ultimate solution to reducing intake temps. However, depending on your racing class, budget, and time it is a workable solution that can be made to act like a poor man's VMIC with proper ducting techniques.

Something else to consider is auxiliary injection.

Here are my duct mod test results: https://www.rx7club.com/3rd-generati...temps-1070765/
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Old 02-05-19, 02:47 PM
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Alex, I think you're right on point. Your statement about the fan only working up to a certain speed actually is accurate for the radiator fans too. But when sitting still with the car idling, the rad fans can keep the air flow moving through the radiator but the intercooler doesn't typically have that same luxury. Having a fan to keep the air temps down and prevent SMIC from heat soaking while sitting still could solve a lot of problems. For as cheap and easy as it is to add a small fan I think I'll end up doing it regardless of which SMIC I go with.
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