Interchiller install (whipple GT350) and initial report

[MKL_DS]

At 7500 rpm, the blower is making 19 psi of boost.

Not if you limit airflow with the throttle.

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[engineermike]

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?

Like I said in post 12, it uses the throttle to achieve the desired load at 7500 rpm, just like it would at 4000 or 2000 rpm.

 

[Angrey]

Like I said in post 12, it uses the throttle to achieve the desired load at 7500 rpm, just like it would at 4000 or 2000 rpm.

And just like I replied, that PHYSICALLY doesn't make any sense. If you close the throttle blade, how does it achieve rpm? If you feed it enough throttle to achieve rpm, you now have a boost issue.

You can't spin the blower at 7500 rpms and NOT make sauce. That's the problem with a PD blower setup.

 

[engineermike]

And just like I replied, that PHYSICALLY doesn't make any sense. If you close the throttle blade, how does it achieve rpm? If you feed it enough throttle to achieve rpm, you now have a boost issue.

You can't spin the blower at 7500 rpms and NOT make sauce. That's the problem with a PD blower setup.

In order to control the load it doesn’t close the throttle all the way. It *modulates* the throttle to target the airflow needed to achieve the desired load. The throttle has many possible positions between open and closed.

 

[MKL_DS]

And just like I replied, that PHYSICALLY doesn't make any sense. If you close the throttle blade, how does it achieve rpm? If you feed it enough throttle to achieve rpm, you now have a boost issue.

You can't spin the blower at 7500 rpms and NOT make sauce. That's the problem with a PD blower setup.

Great example here is a factory Cobra Jet. The initial calibration never allows for 100% throttle. Thus it limits power. Once the driver has exhibited control of the car, Ford Racing will load the new cal that allows for WOT and full boost.

 

[Angrey]

Great example here is a factory Cobra Jet. The initial calibration never allows for 100% throttle. Thus it limits power. Once the driver has exhibited control of the car, Ford Racing will load the new cal that allows for WOT and full boost.

I'm not disagreeing with any of that, the part I'm struggling with is if you don't open the throttle fully, how can you achieve 7500 rpms. And IF you achieve 7500 rpms, the very nature of a positive displacement blower is that it's pushing positive displacement.

I realize you can choke the throttle. The issue is doing that and still being able to rev.

My car made over 600 ft-lbs of torque at 2850. So what's the solution? Choke the throttle, okay, fine, but then you never get above 2850 rpms. On a blower/turbo setup where you can bleed/waste excess, it makes sense. Without some outlet, you can't spin a 3.0 liter blower at near 8,000 rpms and not be moving SIGNIFICANT amounts of air. And if you're moving signficant amounts of air, either one of two things is happening. Either the motor is consuming it as fast as you can move it (zero pressure) OR the motor can gulp the air and use it as fast as you're sending it and voila, the magic of boost/pressure happens and the flow backs up to create charged condition.

 

[engineermike]

I'm not disagreeing with any of that, the part I'm struggling with is if you don't open the throttle fully, how can you achieve 7500 rpms.

If you go out to your car right now, can you not push in the clutch and use the throttle to slowly increase the engine speed to 7500 and hold it steady there? I know I can on mine, if I so choose.

And IF you achieve 7500 rpms, the very nature of a positive displacement blower is that it's pushing positive displacement.

You are correct that the volumetric flow doesn't change when you throttle the inlet air, for the reasons you mention. However, the mass flow does change when you throttle the inlet because the air density entering the blower is much lower. The throttle still works just as it should and modulates flow. If what you were saying were correct, you couldn't throttle an NA engine either because it is also a positive displacement device.

My car made over 600 ft-lbs of torque at 2850. So what's the solution? Choke the throttle, okay, fine, but then you never get above 2850 rpms.

So you can't drive down the road at 3500 rpm and hold a steady speed because it's either all or nothing once you surpass 2850?

Without some outlet, you can't spin a 3.0 liter blower at near 8,000 rpms and not be moving SIGNIFICANT amounts of air.

With the inlet throttled it will move less air, as explained.

 

[engineermike]

Hey Angrey, if you're running the Whipple OS, then you can prove this to yourself by unplugging the MCT sensor. The PCM will limit the load to 0.75 to manage the failure and you will see that it still drives fine and will pull to high rpm, but it will have the power and torque of a v6 Camry.

 

[Angrey]

If you go out to your car right now, can you not push in the clutch and use the throttle to slowly increase the engine speed to 7500 and hold it steady there? I know I can on mine, if I so choose.



You are correct that the volumetric flow doesn't change when you throttle the inlet air, for the reasons you mention. However, the mass flow does change when you throttle the inlet because the air density entering the blower is much lower. The throttle still works just as it should and modulates flow. If what you were saying were correct, you couldn't throttle an NA engine either because it is also a positive displacement device.



So you can't drive down the road at 3500 rpm and hold a steady speed because it's either all or nothing once you surpass 2850?



With the inlet throttled it will move less air, as explained.

Still no. You state "the mass flow does change." You'll have to demonstrate that. The blower draws in ambient air and the volume combined with the temperature and pressure yields the mass flow. You can't just magically say "well now because I changed the load tables it's drawing in less dense air." When you free spin the motor, it's free to make whatever it wants. And yes, in order to not stumble, it has to add appropriate amounts of fuel and spark to keep it going, which obviously changes depending on the load you're applying to the flywheel.

To complicate matters, using a mechanical bypass gets a vote (on what it actuates) my point is, if you spin a 3.0 blower at 7500 rpms, it's going to create MASSIVE airflow and that air flow has to go SOMEWHERE.

Are you saying that the air loads greatly affect the AFR and it just sends unnecessary air through the system (at some crazy high A/F?)

I gotta be honest Mike, normally your stuff is brilliant, but what your proposing begs the question of why NO OTHER TUNER offers a true flex fuel tune for PD blower setups.

With the MOTEC, I'm certain they can hamstring the car on 93, but the fact that the car makes 16 psi of boost very low is going to be problematic. Mark my words. If I was on 8 or 10 psi wastegate and they could simply bleed off any excess it wouldn't be an issue. The only thing (again) is I have an electronically controlled bypass that could modulate and do what you're describing, it would use the throttle angle but in the end, when that's expended and the car still needs to make rpm (without extra boost) the easiest solution is to just bleed it off or waste it or "bypass" it. With my bapass held complely open, I'd imagine the blower won't be able to make much boost at all. With a normal bypass closed (long before 7500 rpms) I just don't see what you're doing with all the extra air (oxygen) the blower is sending SOMEWHERE.

 

[MKL_DS]

Still no. You state "the mass flow does change." You'll have to demonstrate that. The blower draws in ambient air and the volume combined with the temperature and pressure yields the mass flow. You can't just magically say "well now because I changed the load tables it's drawing in less dense air." When you free spin the motor, it's free to make whatever it wants. And yes, in order to not stumble, it has to add appropriate amounts of fuel and spark to keep it going, which obviously changes depending on the load you're applying to the flywheel.

To complicate matters, using a mechanical bypass gets a vote (on what it actuates) my point is, if you spin a 3.0 blower at 7500 rpms, it's going to create MASSIVE airflow and that air flow has to go SOMEWHERE.

Are you saying that the air loads greatly affect the AFR and it just sends unnecessary air through the system (at some crazy high A/F?)

I gotta be honest Mike, normally your stuff is brilliant, but what your proposing begs the question of why NO OTHER TUNER offers a true flex fuel tune for PD blower setups.

With the MOTEC, I'm certain they can hamstring the car on 93, but the fact that the car makes 16 psi of boost very low is going to be problematic. Mark my words. If I was on 8 or 10 psi wastegate and they could simply bleed off any excess it wouldn't be an issue. The only thing (again) is I have an electronically controlled bypass that could modulate and do what you're describing, it would use the throttle angle but in the end, when that's expended and the car still needs to make rpm (without extra boost) the easiest solution is to just bleed it off or waste it or "bypass" it. With my bapass held complely open, I'd imagine the blower won't be able to make much boost at all. With a normal bypass closed (long before 7500 rpms) I just don't see what you're doing with all the extra air (oxygen) the blower is sending SOMEWHERE.

The blower can only move a ton of air at 7500 if its being fed a ton of air. Go put a stock throttle body in front of your whipple and watch power and load drop at WOT.
IMO you are overthinking this. Limit the airflow, and you can limit power and load.

FWIW, in regard to this statement:

I gotta be honest Mike, normally your stuff is brilliant, but what your proposing begs the question of why NO OTHER TUNER offers a true flex fuel tune for PD blower setups.

I'm pretty sure Mikes personal calibration is full of changes NO OTHER TUNER offers, and there are lots of reasons for that. I'm just glad he bothers sharing most of what he has learned in figuring out his combo.

 

[engineermike]

Still no. You state "the mass flow does change." You'll have to demonstrate that.

I already have and I explained it earlier. I set a load limiter in my own car at 1.0 with a whipple pullied for about 15 psi at the time. When I put my foot to the floor, the boost went to about 0 and it held that all the way to 7500. It did so using the throttle blade to modulate the airflow. Flow linearly rose up to about 40 lb/min as rpm increased. This isn't just theory I'm talking about; it works in practice as well.

The blower draws in ambient air and the volume combined with the temperature and pressure yields the mass flow.

Correct, and "pressure" is the key to understanding this. The TB, when throttled, reduces the pressure. So the density of the air entering the blower is lower than if the throttle were wide open. This is how TB throttling controls load.

You can't just magically say "well now because I changed the load tables it's drawing in less dense air."

No magic involved. The pcm calculates how much air it takes to achieve a target max load and modulates the throttle the exact amount that it needs to achieve that load.

To complicate matters, using a mechanical bypass gets a vote (on what it actuates) my point is, if you spin a 3.0 blower at 7500 rpms, it's going to create MASSIVE airflow ...

Bringing the bypass valve into it complicates things unnecessarily. What I am saying is true with or without the bypass. Superchargers didn't always have them but they were totally controllable at high rpm even with stone-age cable throttles. I disabled the bypass valve on my old Gen2 Lightning just for fun and it still drove fine, even at high rpm and part throttle.

Are you saying that the air loads greatly affect the AFR and it just sends unnecessary air through the system (at some crazy high A/F?)....With a normal bypass closed (long before 7500 rpms) I just don't see what you're doing with all the extra air (oxygen) the blower is sending SOMEWHERE.

No unnecessary air goes through the system. The fuel flow matches the modulated airflow.

I gotta be honest Mike, normally your stuff is brilliant,

Thanks?

begs the question of why NO OTHER TUNER offers a true flex fuel tune for PD blower setups.

I'm almost to the point I believe this has to do with lack of HPTuners parameters. PCMTech has shed light on all sorts of flex paramters that was missing from HPT definitions. I have a flex tune in my car that I am quite confident in, but I'm still testing it on transitions.

With the MOTEC, I'm certain they can hamstring the car on 93, but the fact that the car makes 16 psi of boost very low is going to be problematic.

I think MOTEC does load control as well, similar to stock.

 

[Cory S]

Why is there so much concern about post compressor IAT when using plenty of octane? Dropping post compressor IAT doesn’t do much at all. The air density coming into the intake is 100% of the oxygen ingested. On a crank driven blower setup, you’re not magically creating oxygen @ X RPM by lowering the intake charge temperatures. We used to run 270° post blower IAT 25 years ago. Obviously octane was plenty sufficient. We then tested a big A/A IC on the setup. You know what happens? You loose boost from the air temperature drop. We had to spin the blower faster to make up for it. When we did and got boost back to 24psi, the post compressor air charge was 130° now, and the car ran the SAME mph as previously without an IC.


Dropping post compressor air charge temperature does nothing but allow for less chance of Knock. Now…..drop AMBIENT air temp by 40°, and you’ll see your power go up from more oxygen density entering the intake BEFORE it’s compressed.

A turbo application is a little different however, because boost controllers will up the boost to make up for less DA.

My setup makes identical power whether my WOT IAT2 is 100 or 140°. Spark timing is the same, and as long as the DA is the same, it will continue to do so.

People need to stop worrying about IAT so much. Unless it’s 160+ because there’s probably a problem, then just take it with a grain of salt.

Hotter combustion is also more efficient, but will also be prone to pre-ignition much easier.

So if you’re not octane limited. Go enjoy the car.

 

[Joshinator99]

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.

Agreed, that said your timing table will be identical for the situation you just described. You’re not pulling timing at either 100 degree IAT nor are you pulling timing at 135 degree IAT. There won’t be any power difference at all at that time. On E it will take extremely high IAT to justify pulling any timing at all.

Why is there so much concern about post compressor IAT when using plenty of octane? Dropping post compressor IAT doesn’t do much at all. The air density coming into the intake is 100% of the oxygen ingested. On a crank driven blower setup, you’re not magically creating oxygen @ X RPM by lowering the intake charge temperatures. We used to run 270° post blower IAT 25 years ago. Obviously octane was plenty sufficient. We then tested a big A/A IC on the setup. You know what happens? You loose boost from the air temperature drop. We had to spin the blower faster to make up for it. When we did and got boost back to 24psi, the post compressor air charge was 130° now, and the car ran the SAME mph as previously without an IC.


Dropping post compressor air charge temperature does nothing but allow for less chance of Knock. No drop AMBIENT air temp by 40°, and you’ll see your power go up from more oxygen density entering the intake BEFORE it’s compressed.

A turbo application is a little different however, because boost controllers will up the boost to make up for less DA.

My setup makes identical power whether my WOT IAT2 is 100 or 140°. Spark timing is the same, and as long as the DA is the same, it will continue to do so.

People need to stop worrying about IAT so much. Unless it’s 160+ because there’s probably a problem, then just take it with a grain of salt.

Hotter combustion is also more efficient, but will also be prone to pre-ignition much easier.

So if you’re not octane limited. Go enjoy the car.

Very well said. I guess this is how I wished I had explained it LMAO.

 

[Cory S]

Agreed, that said your timing table will be identical for the situation you just described. You’re not pulling timing at either 100 degree IAT nor are you pulling timing at 135 degree IAT. There won’t be any power difference at all at that time. On E it will take extremely high IAT to justify pulling any timing at all.


Very well said. I guess this is how I wished I had explained it LMAO.

People forget Air density (oxygen molecules) doesn't increase after it's compressed. It allows you to stuff MORE air in yes, but unless you spin your blower faster to make up for that, you gain NOTHING.

 

[Angrey]

Why is there so much concern about post compressor IAT when using plenty of octane? Dropping post compressor IAT doesn’t do much at all. The air density coming into the intake is 100% of the oxygen ingested. On a crank driven blower setup, you’re not magically creating oxygen @ X RPM by lowering the intake charge temperatures. We used to run 270° post blower IAT 25 years ago. Obviously octane was plenty sufficient. We then tested a big A/A IC on the setup. You know what happens? You loose boost from the air temperature drop. We had to spin the blower faster to make up for it. When we did and got boost back to 24psi, the post compressor air charge was 130° now, and the car ran the SAME mph as previously without an IC.


Dropping post compressor air charge temperature does nothing but allow for less chance of Knock. No drop AMBIENT air temp by 40°, and you’ll see your power go up from more oxygen density entering the intake BEFORE it’s compressed.

A turbo application is a little different however, because boost controllers will up the boost to make up for less DA.

My setup makes identical power whether my WOT IAT2 is 100 or 140°. Spark timing is the same, and as long as the DA is the same, it will continue to do so.

People need to stop worrying about IAT so much. Unless it’s 160+ because there’s probably a problem, then just take it with a grain of salt.

Hotter combustion is also more efficient, but will also be prone to pre-ignition much easier.

So if you’re not octane limited. Go enjoy the car.

When you "hot lap" and you begin a pull immediately following a pull, you start with higher IAT2 and therefore end with higher IAT2. All of which is a threat to knock resistance and safety of the motor ultimately. The only other choice, irrespective of the fuel is to reduce timing which in turn saps power.

Even on E85 or race fuel, MOST people tend to want it tuned to borderline knock. I would agree if you leave a few degrees of flexibility on the table, but if you run it out to what the fuel will allow (at a given temp) then having cooler IAT's simply helps to ensure you don't run into scenarios where you heat soak and smoke the motor.

Go watch Stangmode's video where he smokes his high dollar L&M motor because he hot laps it.

Like most people, I dyno'd from a fairly cold condition (the intercooler system hadn't reached steady/warm state) and so my IAT's even in a very hot shop were really great for the whole rip. In reality, we should have probably heat soaked the car and tuned it to keep it safer.

Having the interchiller helps keep IAT's lower and helps it to recover for sustained or consecutive rips.

The Dodge crowd has been enjoying this setup for years. While I agree that it's more of a concern with 93, even E85 isn't infallible if you flog it hard enough, back to back to back in hot conditions. I don't like to do a rip and then have to wait to bring temps back down again, I wanna go again, immediately. At 12:1 compression with 19 psi on hot South Florida days, it's enough concern for me to want to add some more insurance to protect my investment.

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