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S2 Exige heatsoak issues no doubt still prevalent on all non-chargecooled Lotus models. But for some reading.

http://www.lotustalk.com/forums/f160/maximum-tolerable-iat-236113/

" The stock ECU for certain pulls timing with increasing IAT's. It might also enrich the mixture during open loop (mid throttle or more), but I don't know if the stock programming does that or not. The advantage of enriching the mixture is that vaporization of the extra fuel gives a cooling effect, but it also hurts emissions and mpg, so my guess is that the stock ECU only pulls timing with increasing IAT's.

So the good news is that the engine doesn't self destruct from knock with high IAT's, but you do lose power and the exhaust gas temperatures can go quite high (retarding the timing increases EGT's at WOT). Cleaning the I/C, a larger and more efficient I/C, and most importantly adding air flow ("fettle" the roof intake, a 3 shroud intake, and/or puller fans on the I/C) will all help reduce heat soak."

As an example for the Exige S2 which no doubt is running more boost than the latest V6 Exige to extract 260hp from a tiny 1.8l 4 cylinder, post supercharger temps for a user that recorded the data rose to as high as 228F (109C) with lots of hard running. After installing a larger intercooler and 50/50 methanol/water injection for his upgraded car, he saw the following drops, which is exactly what water injection can do on its own.

Autobahn09152008NoSprayvSpray-vi.jpg

http://www.lotustalk.com/forums/f171/attempting-fix-heatsoak-re-flash-needed-70874/index2.html

Given the Exige V6 does not have any form of intercooling or charge cooling the post supercharger temps are no doubt sometimes hitting over 100 C and as a result the ECU will pull out a ton of timing and you will be left with the power of a N/A Evora since the ECU is trying to cool down the intake charge.

Water injection alone can help act like an intercooler and drop your temps down to the 30-50 C range just like the larger intercooler this guy had on his S2 Exige did before he also added water and meth to the mix.

 

6 minutes ago, NW76 said:

Yep - I know the channel is there in the Evora Protocol (which I use on my AIM) but on the Exige V6 this channel doesnt deliver any values. Most of the others do generate values. So, I always assumed, this channel is not used (doesnt have a sensor!?!?!?) on the Exige but might have on the Evora.

Neither do the Wheel pressure Channels on the Exige for example ;-)

 

 

 

Then it's probably just the firmware for the AIM unit that needs to be updated. Either way, you can guarantee there is an intake air temp sensor because otherwise the car wouldn't know how much fuel to add as it's all part of the equation by reading air flow density and temperature into the engine in order to optimize timing and fuel delivery to create the most efficient combustion.

Try one of the OBD II bluetooth dongles and the Torque app. You will likely see it then.

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40 minutes ago, NickEng said:

Sounds like a good solution to reduce the charge temps if you're tracking your car. I'm getting an odb dongle for my car, does that allow you view the ignition timing or anything else useful? I'm wondering about the easiest way to set up the water injection controller without fitting a load of extra sensors. I'm sure a small nozzle at 100% would be ok but I'd rather it was efficient and have some data to back it up.

At a very minimum to run water injection you will need to give the water injection pump power from the battery and connect another wire to a ground source anywhere on the chassis. Second, to use the water injection by boost level feature you will need to tee in a rubber line from the AEM control unit to an existing vacuum line. That's it.

An OBD II dongle using the Torque app can monitor a ton of stuff through your phone. The ECU sends all sensor information through the OBD II system because that is the diagnostic port where you would check for an error code, etc. and also how a lot of aftermarket chips flash the ECU. 

As a start, I would suggest some of you guys buy an OBD II dongle, download the app to your iPhone or Android phone, sign up for a track day soon, haul ass and enjoy yourself, monitor and log your intake air temps and see how bad the car is heatsoaking.

Then buy a water injection kit when you find out it is in fact heatsoaking :P

 

Examples of Torque app reading possibilities:

https://torque-bhp.com/wiki/Dials

80-torque_app_screem_capture_1499f590d82

508428_121209080911_torque-app-1.jpg

2014-03-01-19-41-30_zps1e26b055.png

 

Edited by cib24
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@cib24 no chance, even with an OBD dongle ... doubt our Lotus Exige ECU uses the channel / the data ... bet there is some workaround in engine management...

@Jack do you get the Intake Air Temperature via the standard ECU channel on your AIM w/o an additional sensor? Any idea?

 

 

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IAT that Roy refers to as being used by all the modern ECUs is what is read at MAF, which is normally right after the air filter. This means that it does not automatically correct for heat soak and most likely it just detects knocks at some point in time and retards ignition. This actually also means that most likely water would help against timing retard quite naturally.

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Naturally, I don't have an Exige so haven't examined the engine myself, but I would imagine the supercharged V6 engines on the Exige and Evora, and on the supercharge I4 engines in the Elise have two sensors. The MAF, which reads air density, and a temperature sensor embedded in the intake manifold below the supercharger, because it is critical for the ECU to be able to measure the correct temperature of the incoming air charge in order to compensate. Superchargers and turbochargers  compress the air and heat it up A LOT, easily 3x the ambient air temp the MAF could read (via measuring air flow rate and density) from the intake pre-supercharger. So, it makes no sense that the Lotus ECU would not have a way to measure the air before it actually goes into the motor.

Every boosted car I have come across had a intake air temp sensor embedded in the intake manifold or post the forced induction power adder as that is the most accurate place to measure the air and be able to determine the right fuel mixture, even if it also had a MAF to measure the air flow rate and density of the air pre-forced induction.

NW76, as for water injection pre- or post-supercharger it doesn't really matter. Because the Lotus cars have roots-style blowers on them the only way you could inject water post supercharger is if you drilled a hole in the intake manifold right below it which is invasive and more difficult than you need it to be. Inject it where I showed in the photos earlier today in the rubber intake hose and it will do its job, i.e. cool the air charge, cool the supercharger, cool the air going into the motor and thus reduce any chance of the ECU retarding timing and thus reducing horsepower by significant amounts.

 

Edited by cib24
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4G63T being one of the most successful boosted engines ever have no IAT other than what is incorporated in MAF in absolute majority of the versions. It is not critically needed in the MAF operated engines (totally different story for MAP) and timing is retarded based on the knock detection, which covers much broader scope of potential causes.

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42 minutes ago, cib24 said:

Naturally, I don't have an Exige so haven't examined the engine myself, but I would imagine the supercharged V6 engines on the Exige and Evora, and on the supercharge I4 engines in the Elise have two sensors. The MAF, which reads air density, and a temperature sensor embedded in the intake manifold below the supercharger, because it is critical for the ECU to be able to measure the correct temperature of the incoming air charge in order to compensate. Superchargers and turbochargers  compress the air and heat it up A LOT, easily 3x the ambient air temp the MAF could read (via measuring air flow rate and density) from the intake pre-supercharger. So, it makes no sense that the Lotus ECU would not have a way to measure the air before it actually goes into the motor.

Every boosted car I have come across had a intake air temp sensor embedded in the intake manifold or post the forced induction power adder as that is the most accurate place to measure the air and be able to determine the right fuel mixture, even if it also had a MAF to measure the air flow rate and density of the air pre-forced induction.

NW76, as for water injection pre- or post-supercharger it doesn't really matter. Because the Lotus cars have roots-style blowers on them the only way you could inject water post supercharger is if you drilled a hole in the intake manifold right below it which is invasive and more difficult than you need it to be. Inject it where I showed in the photos earlier today in the rubber intake hose and it will do its job, i.e. cool the air charge, cool the supercharger, cool the air going into the motor and thus reduce any chance of the ECU retarding timing and thus reducing horsepower by significant amounts.

 

4 cyliinder Lotus cars with an MP62 SC have a map sensor with a temp sensor included (In the boosted side) They also have the IAT in the inlet side (before the supercharger)

The V6 Exige does not measure temps/pressures in the manifold after the supercharger only IAT before the SC

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Fair enough and thank you for the clarifications. Then the ECU is calculating temps before combustion with the MAF, monitoring knock, monitoring O2 sensor readings in the exhaust and EGTs to determine optimal fuel delivery and timing advance/retard on the fly. But heatsoak will affect these readings and the ECU will compensate as hot air increases the chance of knock/detonation which will result in retarded ignition timing, and to avoid that on a supercharged car without an intercooler or charge cooler to cool the air before it enters the motor, water injection is the simplest, least invasive and most cost effective solution.

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Thanks for clarification. Knock detection is what I thought would drive power reduction in the V6 during heat soak...

So anyway this makes the water injection still a interesting solution to try ... if anybody goes that route please keep us posted...

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There is a nice writeup on the komo-tec blog regarding the charge coller impact: http://komo-tec.com/Blog/ex460-effizienztestung-ladeluftkuehler/ Basically reducing air temp from 85° before the cooler to 48° behind, resulting in 15% more air mass flow.

6 hours ago, Jack said:

I don't know how the factory compensates for IATs on the non-intercooled V6….perhaps they have some sort of algorithm that  estimates the temps the intake might actually see post-blower off of what temps the air box sees??  Perhaps, as someone else mentioned, the factory tune/ECU relies on "octane scaling" data (knock detection), as well as some other parameters, like water temp, to determine the amount of timing to pull.  I happen to be able to log that data off of my ECU in the CupR and so far have not seen any "octane scaling" (detonation detection), which would result in timing adjustments.  I do run 100 octane unleaded fuel in my track cars for added protection.

It isn't necessary to do much on the ECU side for IAT. The higher temperature means your have a naturally reduced air flow as you read above and the MAF is simply reading that lower volume.

If you have the choice between a Stairway to Heaven and a Highway to Hell don't forget the Nomex®!

Captain,  Lotus Airways. We fly lower! 

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Well given all what's been written...it's about time Lotus FIXES this issue for good..and for all......nobody wants to have to become a mechanical engineering PHD to find out a proper solution :):):):) even though it's very interesting.....

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6 minutes ago, Swiss360Cup said:

Well given all what's been written...it's about time Lotus FIXES this issue for good..and for all......nobody wants to have to become a mechanical engineering PHD to find out a proper solution :):):):) even though it's very interesting.....

Yes you ought to mention that to them when you're at Hethel and see what their response is.

Black n gold

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8 minutes ago, Stubox said:

Yes you ought to mention that to them when you're at Hethel and see what their response is.

That's the Nr 1 question I have in mind for them tomorrow when I arrive..... I'm very curious about the answer and explanations... which will probably not be an easy fix to do it properly in the constraints of regulation, warranty, etc. Weight control, etc. Etc. Etc.......

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Well didn't get much of an answer..... the problem was acknowledged but only recognized as a temporary problem in certain circumstances, not impairing the overall performance of the car, at least out of the track......... I know....... regarding a charge cooled Exige, as the car is a shoe box it would need further development..... Regarding the Exige itself they'll continue developing and improving it, but couldn't tell me obviously what they were doing, but they are doing........ the solutions discussed on TLF are interesting according to them, incl. the water spraying...... Voilà... not much of an answer, but that's as much as I could get... .so we'll keep hoping, speculating and looking for fixes....

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On 16/05/2017 at 21:36, cib24 said:

At a very minimum to run water injection you will need to give the water injection pump power from the battery and connect another wire to a ground source anywhere on the chassis. Second, to use the water injection by boost level feature you will need to tee in a rubber line from the AEM control unit to an existing vacuum line. That's it.

An OBD II dongle using the Torque app can monitor a ton of stuff through your phone. The ECU sends all sensor information through the OBD II system because that is the diagnostic port where you would check for an error code, etc. and also how a lot of aftermarket chips flash the ECU. 

As a start, I would suggest some of you guys buy an OBD II dongle, download the app to your iPhone or Android phone, sign up for a track day soon, haul ass and enjoy yourself, monitor and log your intake air temps and see how bad the car is heatsoaking.

Then buy a water injection kit when you find out it is in fact heatsoaking :P

In an Exige V6, most probably everything can be installed in the trunk behind the engine, like we see it on pictures of the Elise from the USA, even a one gallon tank of liquid......really looks like a great solution... and than, add the TVS 1900.... and off we go..... this water injection must be less than € 1'000.- including professional installation by a trained mechanics........ I will talk to mine starting tomorrow.......  For us it's really a problem since most of our track days are done in the south (Italy, France), the further north we go is Spa, Bugatti and Nurburgring and it's really far away... I'm only 2H30 from Monza.... and in the South, temperatures are well above 30 C during the summer months. Even where I live it's easily between 30 and 35 for several weeks in a row...we already had almost 30 a couple of days ago....... and with the global warming things won't get any better.......

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Some interesting reading on the AEM system installation.

But does the ECU need to be recalibrated to compensate for the injection fo methanol/water ???? Looks to me as a yes from the reading but I'm not sure. Does the Lotus ECU compensate automatically as is also suggested from the article in a number of modern cars ????

Wouldn't it be nice to have a specific separate topic for that ?????

And happy bday to @Bibs since apparently it is today.....

http://www.dragzine.com/tech-stories/fuel-cooling-ignition-tech/installing-and-testing-aems-v2-watermethanol-injection-system/

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