Interchiller install (whipple GT350) and initial report

[Angrey]

Okay, so I had a chance to do a second longer trip (than the trip home) this weekend and here's the first draft of the report/findings.

Some background. I have quite a bit of observed data with respect to IAT's on a fairly rowdy setup (I'm making around 1000 rwhp on a 2.75" pulley, full GT350 build, ported heads, 2" primary long tubes, full 3" exhaust, etc).

When cruising in South Florida, I generally observe about 12-15 over ambient when it's blistering hot, and I've seen steady state IAT's below 10 degrees in more moderate weather. Like naturally aspirated, it's a parabolic phenomenon where the faster you cruise, the lower the IAT's get until you reach the sweet spot balance between air flow and engine load. Once the engine starts to load (say 85-90 mph) the airflow is beneficial but the motor is making more heat with rpm/load to maintain speed and the blower is making more boost and adding compression temps, etc)

WIth the whipple setup, I still generally observe this to be between 80-95 mph, depending on the ambient temp.

Interestingly, in hot conditions, when doing a full WOT rip (starting around 100F IAT2) I observed IAT's climbing to over 130, 140 etc. Interestingly enough, the fans just can't cool the car while idling and the IAT2's continue to climb when sitting still so the only way to reasonably bring them back down to say 100F or lower is to cruise gingerly with the car. SItting idling won't do it.

So I contemplated adding the interchiller but installed differently than FI Interchillers generally recommends. I'm not using it for drag racing but more for general lowering of the IAT2, quick recovering of the IAT2 and sustained or back to back pulls to avoid additional risk to the motor and/or losing power with timing reductions.

The typical drag setup is to do 2 separate loops. A loop to and from the ice tank/reservoir and then a second pump that sends chilled coolant to and from the blower (with no intercooler).

I've had my A/C compressor go out (and have plenty of friends that have dealt with evaporators, compressors, you name it, Ford did us few favors on the A/C system reliability). So I wanted to keep my intercooler. The problem with an intercooler is that it works in both directions. If you send it hot coolant, it will exhange with ambient temps to bring it down. However, if you send it cold coolant, it will exchange with the hotter ambient sink to bring temps up (defeating the purpose).

To avoid using a second pump (the primary Pierberg already draws 36 amps) I elected to install a single loop, with the interchiller after the intercooler prior to the reservoir. This retains my intercooler (in the event that the A/C system should fail), keeps the entire system to one big badass pump and has a 3rd aspect of efficiency. (we'll discuss the efficiency aspect in follow on posts). Basically, you get more out of an exchange when the temperature differences are greater than you do when they're closer together. More on that later.

So, in the first long drive (90 miles each way), I observed roughly 12-15 degrees below ambient when it was 96F here (I was seeing low 80's IAT2). Later I saw high 70's IAT2 when the temp had dropped to low 90's.

What's interesting is that the IAT2's drop RAPIDLY when I go WOT. In a split second they drop several degrees and I can't really keep my eyes on the road and the gauges to have more than general observation. When cruising at steady state, and I mash in any gear, the IAT2 instantly starts dropping several degrees.

I haven't decided if that's because of a sudden onrush of cooler air or if there's something in the pump wiring/logic that's creating more coolant flow through the blower. I wanted to keep the activity logic of the FPDM (initial prime, then off until vehicle on) but we found that the variable frequency was giving the internal pump relay fits, so we used the FPDM to a relay, to the pump primary power and wired the pump relay and primary power through that. I still haven't decided if that's giving me full pump speed all the time and haven't figured a way to measure pump speed or coolant flow while I'm driving. Welcome any thoughts on the matter. I don't remember observing rapid drops in IAT2 when hammering before, but admittedly I don't remember watching them until after.

The good news is that the entire system is doing what I wanted. I never really wanted ice cold IAT's for power I just wanted them to recover faster and start below ambient (more for protection than any power enhancement).

The entire system is pretty spendy with all things. 16AN or 1" fittings are NOT cheap and I'm running everything with a full package PNR rear mounted tank and Pierberg 400 pump.

But what was lovely about the whole thing was driving 1000 rwhp whippled car for an hour ripping back and forth and never seeing the temps rise above ambient (ever) and despite all you pansies that live in dry heat areas, it's HOT AF here these days. High 90's ambient with mid 100+ teens for heat index.

I didn't have the energy or patience for the installation so I paid a local shop to do it, they created the custom interchiller bracket (that mounts BELOW my existing birthday cake in the front of the car, just behind the intercooler/radiator/condenser and below them (almost touching the bottom belly pan). They also did a custom switch wiring in the rear wall of my console compartment (out of the visibility) if I ever want to turn the main cabin A/C off (for track purposes). All the penetrations through the firewall are bulkhead sandwich unions, the whole thing is very well done. All in total, it's approaching near $5k (with the installation, various fittings, PNR setup, Interchiller, Nitrate free antifreeze, refrigerant/pag restore, etc).

I'm pretty happy now with gobs of power and no heat soak concerns on E85. I'll try to get some photos up.

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[Austin1992]

Look forward to seeing pictures!

I want to do an interchiller while retaining the heat exchanger also. Plan on using one of these

https://killerchiller.com/shop/ols/products/12v-3-way-bypass-valve-kit

 

[Angrey]

Look forward to seeing pictures!

I want to do an interchiller while retaining the heat exchanger also. Plan on using one of these

https://killerchiller.com/shop/ols/products/12v-3-way-bypass-valve-kit

FI recommended that type of setup, but I wasn't looking for storing up icy cold reservoir and using it in limited applications (like dragging). I was looking more for long term/steady state.

With a 3 way, it's nice because you can overchill a reservoir and then have momentary lower IATs but you have to switch back and forth between the loops.

I'd rather have ambient all the time than over ambient sometimes (with the intercooler loop) and under ambient for limited uses.

By the way, do your research on the differences between FI Interchillers and Killer Chiller. Saw some pretty BAD reviews of the Killer Chiller setup (not sure if you're just planning on using the bypass valve or their whole setup).

 

[Austin1992]

FI recommended that type of setup, but I wasn't looking for storing up icy cold reservoir and using it in limited applications (like dragging). I was looking more for long term/steady state.

With a 3 way, it's nice because you can overchill a reservoir and then have momentary lower IATs but you have to switch back and forth between the loops.

I'd rather have ambient all the time than over ambient sometimes (with the intercooler loop) and under ambient for limited uses.

By the way, do your research on the differences between FI Interchillers and Killer Chiller. Saw some pretty BAD reviews of the Killer Chiller setup (not sure if you're just planning on using the bypass valve or their whole setup).

I’m more into drag racing and roll racing so I’m wanting those quick bursts of max cooling. I also drive with the windows down between 60-90 degrees so I want to retain the heat exchanger when I’m not running ac/defrost. I definitely plan on going with interchiller, just looking at killer chillers valve. Anything is better than current set up though, I have a mishimoto oil cooler that the air hits before the heat exchanger that’s trying to cool the notoriously inefficient intercooler of a roush.

Surely you would have sustained below ambient temps with the pnr tank you’re running. That’s a lot of fluid to heat up lol

What simple/reliable system could we add to program/control the 3 way switch to intake and ambient temp? Say iat2 gets hotter than ambient, valve flows through heat exchanger and once cool again, bypasses it.

 

[engineermike]

@Angrey you run e85 all the time?

 

[Angrey]

@Angrey you run e85 all the time?

Yes, I have the MOTEC coming up, but right now I don't have full flex capability. Even when they integrate my flex fuel sensor with the motec, I'm not sure if we'll be able to get true flex fuel capability with the whipple, because I'm running such a small pulley. Totally neutered I don't know that you could pull enough timing or add enough fuel to keep things safe when it makes 19 lbs of boost peak (16 psi before 3k rpms). I have a smooth boost which they can integrate and probably get there, but that's probably asking for a lot of trail blazing on the tuner/MOTEC's part. We'll see. They might be able to get me something that keeps it from making steam if they integrate the smoothboost bypass into the equation.

 

[engineermike]

The oem pcm has logic that can actually limit load as a function of ethanol %. It could do something like a 1.6 load limit on gasoline and 3.0 limit on e85.

So what’s the end-goal of the interchiller on e85?

 

[Angrey]

I’m more into drag racing and roll racing so I’m wanting those quick bursts of max cooling. I also drive with the windows down between 60-90 degrees so I want to retain the heat exchanger when I’m not running ac/defrost. I definitely plan on going with interchiller, just looking at killer chillers valve. Anything is better than current set up though, I have a mishimoto oil cooler that the air hits before the heat exchanger that’s trying to cool the notoriously inefficient intercooler of a roush.

Surely you would have sustained below ambient temps with the pnr tank you’re running. That’s a lot of fluid to heat up lol

What simple/reliable system could we add to program/control the 3 way switch to intake and ambient temp? Say iat2 gets hotter than ambient, valve flows through heat exchanger and once cool again, bypasses it.

It's physically impossible to run below ambient without a chiller/cooler sink in the equation (other than ambient). The most efficient exchanger in the world can only achieve ambient as maximum theoretical.

Keep in mind, there's going to be a significant lag time when you flip over to the cooling loop for it to cool the reservoir down and for you to see a drop in IAT unless you run an actual proportioning/bypass valve in the cooling loop. Once you flip the refrigerant loop to start using the evaporator in the interchiller, it then has to fight to cool down the entire reservoir, which will take a bit before you'll notice drops in IAT. If you use the bypass on the coolant line, then the refrigerant system will have to be always running (like the interchiller setup) unless you put another bypoass on that system.

I went through all the pros and cons and tradeoffs for each setup and the accounting gets a little crazy in different scenarios/conditions (there's quite a few).

The way I have it setup, if I lose the A/C system, it functions just like it did before, pushing coolant through the intercooler, and then through a dead interchiller so basically just like the previous system but with the added capacity of the PNR tank and the increased flow of the 400 pump.

I thought about changing the default logic on the interchiller system so that I could still retain in cabin A/C on/off and then flip on the interchiller loop, but I wasn't sure if that would endanger the refrigerant system if you active or deactivate it at different times when considering high/low pressure and where the coolant is/isn't at the time of activation.

 

[Angrey]

The oem pcm has logic that can actually limit load as a function of ethanol %. It could do something like a 1.6 load limit on gasoline and 3.0 limit on e85.

So what’s the end-goal of the interchiller on e85?

Again, mostly to just protect against excessive heat soak under sustained or back to back hits. Not really to promote making more power. Just as added insurance if I do a rip and IAT's climb, I can immediately do another rip (back to back) without fear or concern of additional risk (or having the tune be ultra conservative with protections and yanking timing).

I'm not sure how using the load would physically limit the amount of boost (and heat) created by the blower unless you're saying it would use the throttle and even then, again, my car makes 16 psi at 2850 rpm, so if that's the case it wouldn't let me rev above like 2k rpms to keep it from making well over the recommended "limit" for boost on 93. I guess it could kinda function as a "limp" type mode.

 

[engineermike]

Again, mostly to just protect against excessive heat soak under sustained or back to back hits. Not really to promote making more power. Just as added insurance if I do a rip and IAT's climb, I can immediately do another rip (back to back) without fear or concern of additional risk (or having the tune be ultra conservative with protections and yanking timing).

Generally, E85 is much less sensitive to MCT than gasoline. The knock resistance is nuts.

I'm not sure how using the load would physically limit the amount of boost (and heat) created by the blower unless you're saying it would use the throttle and even then, again, my car makes 16 psi at 2850 rpm, so if that's the case it wouldn't let me rev above like 2k rpms to keep it from making well over the recommended "limit" for boost on 93. I guess it could kinda function as a "limp" type mode.

The Ford control system works entirely off of "load". Load is defined by the mass of air in the cylinder divided by the mass of air in the cylinder if at standard temperature and pressure. For instance, an NA engine with 100% VE at WOT will be right at 1.0 load, assuming ambient conditions are standard. From this, you can see that the "boost" threshold (load where boost begins) is 1.0 load or thereabouts. Cruise might be .35 load, and so on. The load is controlled by the throttle blade. Torque is generally roughly proportional to load.

A load limit doesn't limit the rpm, nor act as a limp mode. It just limits the amount of air that gets into the cylinder regardless of rpm. Do you NEED 16 psi boost just to achieve anything over 2000 rpm? I don't think so. I've played with load limits before on mine. Just adding a 1.0 load limit will make the car make about 430 ftlb torque from idle to 7500 rpm and it runs very similar to stock. The load limit modulates the throttle to achieve the target load. Setting something like a 1.5 load limit on gasoline would just limit boost to around 8 psi and it would sustain it from low to high rpm.

It's just an option that any competent tuner can implement. The interchiller would mainly benefit you if running gasoline.

 

[Angrey]

Generally, E85 is much less sensitive to MCT than gasoline. The knock resistance is nuts.



The Ford control system works entirely off of "load". Load is defined by the mass of air in the cylinder divided by the mass of air in the cylinder if at standard temperature and pressure. For instance, an NA engine with 100% VE at WOT will be right at 1.0 load, assuming ambient conditions are standard. From this, you can see that the "boost" threshold (load where boost begins) is 1.0 load or thereabouts. Cruise might be .35 load, and so on. The load is controlled by the throttle blade. Torque is generally roughly proportional to load.

A load limit doesn't limit the rpm, nor act as a limp mode. It just limits the amount of air that gets into the cylinder regardless of rpm. Do you NEED 16 psi boost just to achieve anything over 2000 rpm? I don't think so. I've played with load limits before on mine. Just adding a 1.0 load limit will make the car make about 430 ftlb torque from idle to 7500 rpm and it runs very similar to stock. The load limit modulates the throttle to achieve the target load. Setting something like a 1.5 load limit on gasoline would just limit boost to around 8 psi and it would sustain it from low to high rpm.

It's just an option that any competent tuner can implement. The interchiller would mainly benefit you if running gasoline.

I'm still unclear as to how you can manage the load on a PD blower with a belt and pulley size without involving the throttle and limiting it that way. Again, on something more pedestrian, might work, but on a 2.75 pulley, the blower combined with the low rpm sends boost RIGHT AWAY and at 2850 I make 16 lbs and it peaks at 19 psi somewhere in the mid rpms and then never catches the motor after that and holds at 19 psi through redline.

If you limit the "load" then the only way you could achieve that ("limit how much air is going into the cylinder") is through choking the throttle to keep that incoming air down and that would result in limping it (not allowing it to rev past say 2k rpms).

I do have a smooth boost bypass which could be incorporated, but we'll see, most tuners don't like taking new adventures like that. IF we can integrate the smooth boost to bleed off and bypass boost, then we can rev all we want and not exceed a desired load or output.

Without the bypass of some sort, there's no other way to limit the air coming in because the PD blower is making steam at 3k rpm, you have to do something with it, if it doesn't go into the motor, where else would it go?

At that point, a limp mode style would basically neuter a lot of the desire to be true flex fuel. It would be useful for getting home (or to a station to improve the fuel quality) but wouldn't function nearly like a true flex fuel setup. Obviously flex fuel setups are much easier to employ on a turbo system where you can know that wastegate pressure is 8 psi and then just moderate the wastegate accordingly. With a PD blower (and without something like a variable bypass) there's no other way to manage what the cylinders see because the blower output is directly and inescapably tied to rpm.

 

[engineermike]

If you limit the "load" then the only way you could achieve that ("limit how much air is going into the cylinder") is through choking the throttle to keep that incoming air down and that would result in limping it (not allowing it to rev past say 2k rpms).

I think this is where you're getting confused. Yes, it use the throttle to achieve the desired load. However, that does not create a "limp" or rpm-limited situation. You can hit 7500 rpm at .5 load, 1.0 load, or 2.0 load. The torque production at 7500 will be less or more depending on the load it's throttled to. Like I said, I put a load limiter on mine at 1.0 just for fun and it pulled just like a stock coyote would all the way to 7500 even though the blower is capable of 1.9 load (16 psi) at WOT. It does not limit the rpm at all.

I am NOT talking about a flex fuel rpm-limited "limp home" type control. The throttle can modulate load and is not just an on-off switch. Heck, most ecoboost engines use the throttle to modulate load at WOT (misnomer in this case) not the wastegate anyway.

 

[Joshinator99]

@Angrey you run e85 all the time?

Just as another data point FWIW, my Camaro makes nearly identical power to Angrey’s car (I’m at 1059 WHP @ 18 PSI). I bought an FI Interchiller to install for the exact same IAT reason…until I had a discussion with Mike Sitar (former president of Magnuson Superchargers, now runs TooHighPSI). He advised that I do NOT install the Interchiller since E85 needs a good deal more heat to vaporize and with the knock resistance of E, the IAT is just not that big of a deal anymore. Now 91/93 octane is obviously a different story! Again, I know it’s not a Mustang but thought you guys would find that interesting…very similar situation.

 

[Angrey]

I think this is where you're getting confused. Yes, it use the throttle to achieve the desired load. However, that does not create a "limp" or rpm-limited situation. You can hit 7500 rpm at .5 load, 1.0 load, or 2.0 load. The torque production at 7500 will be less or more depending on the load it's throttled to. Like I said, I put a load limiter on mine at 1.0 just for fun and it pulled just like a stock coyote would all the way to 7500 even though the blower is capable of 1.9 load (16 psi) at WOT. It does not limit the rpm at all.

I am NOT talking about a flex fuel rpm-limited "limp home" type control. The throttle can modulate load and is not just an on-off switch. Heck, most ecoboost engines use the throttle to modulate load at WOT (misnomer in this case) not the wastegate anyway.

At 7500 rpm, the blower is making 19 psi of boost. Not sure what you're doing with that or how you're keeping that out of the motor? I'm not understanding of how you're managing the air that the blower creates, regardless of tune based on the physical constraints of the pulley size and spin of the belt.

The additional air created by spinning the blower has to go SOMEWHERE?

 

[Angrey]

Just as another data point FWIW, my Camaro makes nearly identical power to Angrey’s car (I’m at 1059 WHP @ 18 PSI). I bought an FI Interchiller to install for the exact same IAT reason…until I had a discussion with Mike Sitar (former president of Magnuson Superchargers, now runs TooHighPSI). He advised that I do NOT install the Interchiller since E85 needs a good deal more heat to vaporize and with the knock resistance of E, the IAT is just not that big of a deal anymore. Now 91/93 octane is obviously a different story! Again, I know it’s not a Mustang but thought you guys would find that interesting…very similar situation.

All true, until you've just did a 60-130 in very hot conditions and instead of starting at 100F IAT2, your IAT2 is now at 135F after the pull and you want to do another one. You can wait 5 minutes and drive around moderately to get it back down, or you can mash and either the tune hits temp limitations OR puts the whole setup at more risk. Some fairly famous youtubers have videos of destroyed motors when "hot lapping" roll racing.

For a one time hit or drag racing, I agree. For sustained loads, every fuel is going to be subjected to heat soak concerns.

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