The Lotus Cars Community banner
1 - 9 of 9 Posts

· Premium Member
2006 Exige
Joined
·
1,313 Posts
Discussion Starter · #1 ·
I searched through old posts and I couldn’t find much factual info on the Reverie intake.
A lot of negative stuff about aftermarket intakes but no Dyno or real world testing.
As long as the maf sensor housing is the same diameter as stock I don’t see why a tune would be needed.
The stock air box is fine as it’s already a cold air intake and has a filter with a lot of surface area hence good air flow.It has a vacuum operated flap that sucks air from the hot engine bay at
WOT. I have no idea why they would do such a
odd thing. The second problem I have with it is the bulky snorkel block’s flow air to the engine bay.
The third strike is it ways over 5# and that weight is on the wrong side of the car if your left hand drive.
 

· Registered
Joined
·
830 Posts
A previous owner of my car installed the reverie (daytona, i think) cf intake. I have not put my car on a Dyno, as I'm not interested in power. I have, on the otherhand, played around with airflow measurements and a bit of rough cfd.



Overall, i didn't see much evidence that it increased airflow, but at the same time don't think it's too much of a detriment. When i played around with the flow adapter between the bell of the intake and the maf tube, i saw the maf reading change so i thought that a tune adjustment was necessary. At the time, i didn't have a stock intake to make a comparison. Instead, i assumed that the oe calibration was correct for the oe intake. Then, any deviation caused by the reverie intake would be noticable in the uego for measurement. I also had the benefit of comparison with steelypip's stock intake measurements, even if that was on a different car in a different part of the country.

If you were local, i would let you put it in your car to see what you thought, or to run a dyno pull.

If you've got any questions about it, I'd be happy to answer.
 

· Administrator
Joined
·
14,953 Posts

· Premium Member
2006 Exige
Joined
·
1,313 Posts
Discussion Starter · #4 ·
A previous owner of my car installed the reverie (daytona, i think) cf intake. I have not put my car on a Dyno, as I'm not interested in power. I have, on the otherhand, played around with airflow measurements and a bit of rough cfd.



Overall, i didn't see much evidence that it increased airflow, but at the same time don't think it's too much of a detriment. When i played around with the flow adapter between the bell of the intake and the maf tube, i saw the maf reading change so i thought that a tune adjustment was necessary. At the time, i didn't have a stock intake to make a comparison. Instead, i assumed that the oe calibration was correct for the oe intake. Then, any deviation caused by the reverie intake would be noticable in the uego for measurement. I also had the benefit of comparison with steelypip's stock intake measurements, even if that was on a different car in a different part of the country.

If you were local, i would let you put it in your car to see what you thought, or to run a dyno pull.

If you've got any questions about it, I'd be happy to answer.
Thanks for your response, I had no idea how little I knew about this subject.From your diagram I see Reverie doesn’t have a radius or flow adapter. I won’t be doing that for sure. Did you find the filter in the tube reduced flow below what the engine needed at wot?
I had thought at low throttle opening the system was in closed loop and simply adj afr by what the O2 sensor was telling it.Then at wot it was in open loop and did what the ecu was programmed to do.
I guess it’s not that simple.
The link catsailer provided basically said a straight tube with the air filter on the end worked best. I can do that!! I can machine a maf housing out of aluminum easily enough. I can machine the flow adapter into it if it’s or to be that close I could put it upstream a bit.What do you think would be best?
 

· Registered
Joined
·
830 Posts
The reverie daytona originally intended to re-use the stock inlet flow adapter at the MAF tube.
see here: https://www.reverie.ltd.uk/Downloads/Elise_S2_exige_s2_111r_Daytona_Fitting_Guide.pdf
That's the installation guide that shows the white ~10mm radius with vane (and some dyno plots at the end). I used this flow adapter for a while, but removed it after it gave me trouble.

The trouble came because the inlet adapter is not firmly held in place, just friction; mine fell off and tumbled around in front of the MAF due to vibration. That was an exciting event - full-throttle acceleration, cross onto the second cam airflow increase, then the flow adapter starts tumbling in front of the sensor, then the engine bucks and stalls at clutch-in. oops.

As a gauge of load, I think the engine controls use either MAF or alpha-n on the low cam, depending on throttle rate, but on high cam, the MAF sensor is used absolutely: Notes about 2005 Elise fueling and timing control
I think there is not a sufficient sanity check on the MAF reading, either, and the car even dynamically learns the alpha-n load table based on the MAF. So an error in MAF reading is a catastrophe. I unplugged the MAF sensor and nursed the car home on slow roads after the flow adapter fell off.

As I understand, the load measurement is part of what drives fueling, and as you expect the AFR is modulated in response to O2 sensor readings under closed loop fueling. Even if fueling is open-loop with respect to the oxygen sensor instantaneous reading, the airflow load is still being actively measured and fueling is being trimmed by what was learned during closed loop operation. The airflow learning and fuel trim learning can act to oppose each other, depending on the quality of the calibration. I wonder if that was really the best way to design an engine control system.

Regarding intake/filter flow restriction: since the reverie intake does not use the vacuum intake valve, i placed a pressure sensor on the intake plenum vacuum port, and compared it to the pressure sensor that is onboard the ECU measuring ambient pressure. At wide open throttle, the values were the same (within the tolerance of the sensor), so I thought that the intake and filter did not present a noticeable flow restriction. That being said, the sensor was not meant to measure small differences in pressure - it has a 0-3bar range over 10 bits (i.e. ~3 mbar = 1.2 in H2O resolution). In contrast, reverie published some airflow measurements:
Air Filter Data | Reverie lTD / https://www.reverie.ltd.uk/Downloads/Reverie Ltd Bare Cotton Gauze Air Filter Flow Rate Data_Issue 3_24042020.pdf

I'm not too sure about the engine protection that the K&N filter provides.. fairly large particles can come through that mesh without a dust cover: Cone Conical Air Filter - 152mm (6

Despite playing around with my intake and my other thoughts about this topic, I don't have any practical experience with optimizing airflow. Your plan for a straight intake with machined MAF mount housing sounds reasonable to me. I think that some of off-the-shelf air filters have a built-in radius/velocity stack too, in case you don't want to machine that. I would guess that the best behavior would be achieved with a nice, wall-attached laminar flow across the MAF sensor.
 

· Premium Member
2006 Exige
Joined
·
1,313 Posts
Discussion Starter · #6 ·
The reverie daytona originally intended to re-use the stock inlet flow adapter at the MAF tube.
see here: https://www.reverie.ltd.uk/Downloads/Elise_S2_exige_s2_111r_Daytona_Fitting_Guide.pdf
That's the installation guide that shows the white ~10mm radius with vane (and some dyno plots at the end). I used this flow adapter for a while, but removed it after it gave me trouble.

The trouble came because the inlet adapter is not firmly held in place, just friction; mine fell off and tumbled around in front of the MAF due to vibration. That was an exciting event - full-throttle acceleration, cross onto the second cam airflow increase, then the flow adapter starts tumbling in front of the sensor, then the engine bucks and stalls at clutch-in. oops.

As a gauge of load, I think the engine controls use either MAF or alpha-n on the low cam, depending on throttle rate, but on high cam, the MAF sensor is used absolutely: Notes about 2005 Elise fueling and timing control
I think there is not a sufficient sanity check on the MAF reading, either, and the car even dynamically learns the alpha-n load table based on the MAF. So an error in MAF reading is a catastrophe. I unplugged the MAF sensor and nursed the car home on slow roads after the flow adapter fell off.

As I understand, the load measurement is part of what drives fueling, and as you expect the AFR is modulated in response to O2 sensor readings under closed loop fueling. Even if fueling is open-loop with respect to the oxygen sensor instantaneous reading, the airflow load is still being actively measured and fueling is being trimmed by what was learned during closed loop operation. The airflow learning and fuel trim learning can act to oppose each other, depending on the quality of the calibration. I wonder if that was really the best way to design an engine control system.

Regarding intake/filter flow restriction: since the reverie intake does not use the vacuum intake valve, i placed a pressure sensor on the intake plenum vacuum port, and compared it to the pressure sensor that is onboard the ECU measuring ambient pressure. At wide open throttle, the values were the same (within the tolerance of the sensor), so I thought that the intake and filter did not present a noticeable flow restriction. That being said, the sensor was not meant to measure small differences in pressure - it has a 0-3bar range over 10 bits (i.e. ~3 mbar = 1.2 in H2O resolution). In contrast, reverie published some airflow measurements:
Air Filter Data | Reverie lTD / https://www.reverie.ltd.uk/Downloads/Reverie Ltd Bare Cotton Gauze Air Filter Flow Rate Data_Issue 3_24042020.pdf

I'm not too sure about the engine protection that the K&N filter provides.. fairly large particles can come through that mesh without a dust cover: Cone Conical Air Filter - 152mm (6

Despite playing around with my intake and my other thoughts about this topic, I don't have any practical experience with optimizing airflow. Your plan for a straight intake with machined MAF mount housing sounds reasonable to me. I think that some of off-the-shelf air filters have a built-in radius/velocity stack too, in case you don't want to machine that. I would guess that the best behavior would be achieved with a nice, wall-attached laminar flow across the MAF sensor.
Thanks for the info. I have a lot of trouble believing the 5-7 hp Dyno results that have been reported. If I got a couple hp. and saved 3# I would be happy.
I will buy the Reverie and hope for the best.My son has convinced me not to take on another project.
Thanks for taking the time to explain everything you did.At least I learned some new information.
 

· Premium Member
2006 Exige
Joined
·
1,313 Posts
Discussion Starter · #7 ·
Thanks for the info. I have a lot of trouble believing the 5-7 hp Dyno results that have been reported. If I got a couple hp. and saved 3# I would be happy.
I will buy the Reverie and hope for the best.My son has convinced me not to take on another project.
Thanks for taking the time to explain everything you did.At least I learned some new information.
Update.The shipped price of the Reverie intake came out to over $700.All the shipping and fees really added up.Since the maf housing is a casting which to me is a big minus we have decided to make the whole thing.Will post updates.
 

· Administrator
Joined
·
14,953 Posts
Here's two of many videos on making CF tubes, The second one is funny as well. Looking forward to seeing yours since all of your projects turn out so well!


 
1 - 9 of 9 Posts
Top