TRUTH/MYTH OF LOTUS ECU

[GTsRasta]

As of today, you got yourselves a new dyno to see, and a new race header to purchase!

New race header development thread

Originally Posted by Bane

Flame ON



Stock vs. PPE (ignore the blip at the end)



Stock vs. PPE + Von Hep

What's interesting is the low-end power gains from about 2500-3500 rpm... Overall I'm happy with the gains across the entire powerband. Area under the curve is pretty good IMHO.

I have high-res versions in PDF form if anyone wants them. I also have pricing ready for the group buy but I'm waiting to return to the dyno after I put ~1000 miles on the car to see if it kept the gains.

*edit* One more thing. This dyno was done at a completely un-biased shop with the Mynes operators running it. PPE isn't large enough to have an in-house dyno nor do they have the experience to run it themselves. I usually am slightly skeptical when I see a large company release dyno charts with their own employees running it in house...

These Lotus results look similar to our 4-1 PPE race header results...eerie, huh? Same thing with the Lotus 4-2-1 race header to the Celica 4-2-1 race header...

For the purposes of this thread...I'll be looking forward to his 1000+ mile dyno...

[GTsRasta]

Until Bane posts up his 1000+ mile dyno, I think this should suffice to add on to the thread, even though I'm a bit late to adding it on here. Remember that Weapon R 4-2-1 design race header (like forcedfed's) that a bunch of people though would flop and not produce power just because it was a "ricer company's" product? Well check out the latest dyno & gains (Post #111):

http://www.lotustalk.com/forums/showthread.php?t=50526

Originally Posted by HJZ

Well, 200+ miles and almost 10 days later, the new dyno results are in. Here is the new dyno vs. baseline.


For those that do no remember, peak whp during baseline was 173.6hp.

Compared to the dyno runs that were done directly after, which resulted in peak hp of 173.9, this is a much healthier gain. There are gains everywhere throughout the graph as you can see. Maybe Dustin can post all three graphs (baseline, right after, and 9 days later) so you guys can see the changes.

Sound level wise, it has gotten a little louder. I actually said to myself as Dustin is backing up my car, "wow, that's how it sounds like huh". And that was said in a good way. At idle, the change is almost nonexistent. You cannot tell almost. Under load, it is much more pronounced of a sound, a mixture of howling at cam change and growl at lower cam. Overall a welcomed change. Cabin noise remains level with what I remember since right after the install, maybe just a tad louder.

Car feels strong. Throttle response is so much better. I think if I take out the play in the cable it'll probably be even better . Anyway, I'm way happy with the results since I wasn't really expecting much. You should've seen my face with each dyno pull.

I'm sure Dustin will fill in on the rest of the details and post up some vids and graphs for all to see.

Like OMG...it MADE MORE POWER after the ECU got used to the mod...and it resembles the Forcedfed 4-2-1 race header results and the Celica GTS Weapon R 4-2-1 race header results that has a low-midrange bias, and a tapering loss of power in the top end towards redline. Based on the "losing power after raising VE" methodology here...I think some Gremlins must have tampered with this dyno for it to have gained power everywhere...

Now lets see a PPE Race header dyno versus a Weapon R one!

[timdavis130]

My apologies for dredging up an old thread, especially one with such intense arguments going on, but I really wanted to comment on a couple of issues.

Concerning low and midrange torque:

I definitely agree that this can be an important aspect of engine performance for acceleration, especially when outside of the highest RPM range of the engine. On the other hand, this was clearly not a concern of Lotus engineers when selecting an engine for this vehicle, because if you want low range torque 2ZZ is not the right engine to be working with. The entire idea of this engine is sacrificing low and midrange torque for high range HP. If low and midrange torque is the desired outcome there are other engines that would be more desirable selections (Ecotec?). Same thing if you want an engine that can take a ridiculous amount of boost and make crazy forced induction power, I don't think 2ZZ is the answer.

Concerning the ECU "unlearning" modifications:

I know the accepted answer is that this ECU unlearns modifications over time. After reading many threads and comments here I still do not fully understand how or why though.

From my understanding ECUs make adjustments to meet certain conditions. These adjustments are likely geared to achieve a number of goals, power output, emissions and engine longevity. The primary inputs for these adjustments are the intake sensors (MAF or MAP depending on the engine), the oxygen sensor and the knock sensor. Based on the knock sensor the ECU may retard ignition timing to prevent detonation, this is a longevity issue. Based on the oxygen sensor and the intake sensors the ECU will adjust fuel delivery. Too lean is bad for longevity, too rich is bad for emissions so the ECU makes adjustments to maintain the appropriate AFR.

Since the MAF sensor measures the mass of air that is flowing past it, one would assume that more airflow would result in increased fuel delivery. My understanding is that MAF based ECUs are much better at making these types of adjustments in response to bolt on intake mods than speed/density systems are because the MAF measures the actual amount of air instead of estimating the amount of airflow based on manifold pressure. So, if more air is being delivered I do not understand why the ECU would learn to deliver less fuel overtime as this is not ideal for emissions, longevity or power production. I do understand that at some point you will move outside the ECU's ability to adjust for these changes but for simple low impact intake mods I really don't understand how or why the ECU would "unlearn" the ability to produce more power; it's simply not in its best interest to do so as long as you are within the ECU's range of available adjustments.

Either way, I think I agree with GTsRasta that the ECU should not be unlearning power increases from simple intake mods, and I agree that the spirit of the engine is high end power, not low range torque.

If improved low range torque is the goal, maybe a different cam is the answer. Idle to 6200 rpms is a pretty broad range for a cam, so I would suspect that even the "first" cam has significant overlap (don't know the cam specs), which is good for high RPM power but bad for low/mid RPM torque. So maybe the ultimate mod is a new cam with a more midrange grind for the lowrange lobes and then a lower cam switch over point to go to the highrange cam?

[GTsRasta]

Originally Posted by timdavis130

My apologies for dredging up an old thread, especially one with such intense arguments going on, but I really wanted to comment on a couple of issues.

Concerning low and midrange torque:

If low and midrange torque is the desired outcome there are other engines that would be more desirable selections (Ecotec?). Same thing if you want an engine that can take a ridiculous amount of boost and make crazy forced induction power, I don't think 2ZZ is the answer.

Finally somebody gets it. There's an option to get an ECOTEC motor swapped into your car now in the aftermarket vendor section...but why? BMW decided to use their 8,400 rpm high revving V8 instead of a torquier one with more displacement in their new M3 for a reason. I think the same reason is for the 2zz in the Lotus as well, which is why sleepless's build is waiting for a new custom intake manifold that will RAISE peak hp/tq by 1,000 rpm or so. And I don't think the other Toyota 1.6 liter 10,000 rpm was meant to be a midrange torque monster as well...I wonder how many of those builds have low-midrange oriented headers...

Originally Posted by timdavis130

I do understand that at some point you will move outside the ECU's ability to adjust for these changes but for simple low impact intake mods I really don't understand how or why the ECU would "unlearn" the ability to produce more power; it's simply not in its best interest to do so as long as you are within the ECU's range of available adjustments.

I dug up most of the posts and threads relating to the issue here. The answers are there, and there have been reports of power loss. But based on this thread...I have yet to see a dyno that had 100% power loss in all RPM ranges...

Originally Posted by timdavis130

If improved low range torque is the goal, maybe a different cam is the answer. Idle to 6200 rpms is a pretty broad range for a cam, so I would suspect that even the "first" cam has significant overlap (don't know the cam specs), which is good for high RPM power but bad for low/mid RPM torque. So maybe the ultimate mod is a new cam with a more midrange grind for the lowrange lobes and then a lower cam switch over point to go to the highrange cam?

You sir, are correct:

http://www.newcelica.org/forums/showthread.php?t=273079

Originally Posted by Redliner9k

In my own personal experience, yes. I've tuned 2 cars with them and there great in the midrange but lack HEAVILY after 7500rpm.

He's talking about the Piper Stage 2 cams by the way. When you have a built head to properly house the piper stage 3 cams, that's when the increased duration in the big lobe can see more top end power. But then again, everybody and their moms here are running to reflashes that they won't be able to enjoy custom tunes with all these nice parts Celica people are grabbing up...

And on that note...look at the NEW Lotus PPE race header dyno update:

New race header development thread

Originally Posted by Bane

What you're looking at is a comparison between the following:

- Lighter color = PPE header + high flow cat + Larini 0 miles and 10 minutes after install

- Darker color = PPE header + high flow cat + Larini 1700 miles and 2 months after install.

Just to say it again, the car really doesn't have 210 RWHP. It was a Mustang dyno and I think the Elise's weight was throwing it off. What's important is the relative difference.

Like ZOMG...a properly engineered breather mod makes power without ANY loss of power in the powerband...and with the top end being the focus instead of LOSING power in LIFT like the forcedfed 4-2-1 race header design...

[Rugbyduck]

Holy $hit! This thread is an absolute bitch to read and follow. I'm going back to playing Dungeons and Dragons. Oh...wait...I don't play Dungeons and Dragons...

[TimMullen]

Originally Posted by timdavis130

the ECU should not be unlearning power increases from simple intake mods,

It's not so much that the ECU "unlearns" - it's actually more like it "learns".

When you change the intake filter, you change the mixture - at least for a while. The tendency is to lean out the mixture a bit and this in turn makes more power. But the ECU "learns" its new conditions and makes long term adjustments to the mixture - this negates the temporary leaning (and power improvements) by returning things to "normal". The ECU is attempting to keep things in compliance with the emission regulations, not necessarily in making small improvements in power.

[probax]

Just for curiosity:
why LotusSport would sell an intake with higher air flow if they risk a decrease in torque and hp. Anybody out there who checked this one from LotusSport:

[Randy Chase]

It gets a bit frustrating saying the same things over and over.

I ran that intake on my car for over a year and it is still on my ex-car. It does not and did not lose hp or torque. It gained. Dyno tested. We also tested many different intakes and they DID lose torque or hp. Some up to 9hp. Some gains were seemingly caused by the engine running lean because the intake fooled the MAF temporarily, but eventually the ECU recalibrated the fuel maps and gains would go away.

[masheen]

thank you timdavis130. yours below is the only kind of philosophical assessment of this topic that makes sense to me (also acceptable to me is the pragmatic approach of testing what works and what doesn't and not worrying too much about why). and it's also put simply and clearly. i meant to write up something like this too but never go to it. i program ECUs for a living.

Originally Posted by timdavis130

Concerning the ECU "unlearning" modifications:

I know the accepted answer is that this ECU unlearns modifications over time. After reading many threads and comments here I still do not fully understand how or why though.

From my understanding ECUs make adjustments to meet certain conditions. These adjustments are likely geared to achieve a number of goals, power output, emissions and engine longevity. The primary inputs for these adjustments are the intake sensors (MAF or MAP depending on the engine), the oxygen sensor and the knock sensor. Based on the knock sensor the ECU may retard ignition timing to prevent detonation, this is a longevity issue. Based on the oxygen sensor and the intake sensors the ECU will adjust fuel delivery. Too lean is bad for longevity, too rich is bad for emissions so the ECU makes adjustments to maintain the appropriate AFR.

Since the MAF sensor measures the mass of air that is flowing past it, one would assume that more airflow would result in increased fuel delivery. My understanding is that MAF based ECUs are much better at making these types of adjustments in response to bolt on intake mods than speed/density systems are because the MAF measures the actual amount of air instead of estimating the amount of airflow based on manifold pressure. So, if more air is being delivered I do not understand why the ECU would learn to deliver less fuel overtime as this is not ideal for emissions, longevity or power production. I do understand that at some point you will move outside the ECU's ability to adjust for these changes but for simple low impact intake mods I really don't understand how or why the ECU would "unlearn" the ability to produce more power; it's simply not in its best interest to do so as long as you are within the ECU's range of available adjustments.

Either way, I think I agree with GTsRasta that the ECU should not be unlearning power increases from simple intake mods, and I agree that the spirit of the engine is high end power, not low range torque.

If improved low range torque is the goal, maybe a different cam is the answer. Idle to 6200 rpms is a pretty broad range for a cam, so I would suspect that even the "first" cam has significant overlap (don't know the cam specs), which is good for high RPM power but bad for low/mid RPM torque. So maybe the ultimate mod is a new cam with a more midrange grind for the lowrange lobes and then a lower cam switch over point to go to the highrange cam?

[Cali]

Originally Posted by Randy Chase

It gets a bit frustrating saying the same things over and over.

I ran that intake on my car for over a year and it is still on my ex-car. It does not and did not lose hp or torque. It gained. Dyno tested. We also tested many different intakes and they DID lose torque or hp. Some up to 9hp. Some gains were seemingly caused by the engine running lean because the intake fooled the MAF temporarily, but eventually the ECU recalibrated the fuel maps and gains would go away.

So the TRD airbox (by itself) DOES increase power? And if so, is it noticeable?

[Randy Chase]

Yes and not a lot.

[MaineLotus]

Originally Posted by Randy Chase

Yes and not a lot.

Randy, were you running MAF or MAP? EFI?

[Randy Chase]

When we first used the "stage 3" intake above, it was with a Lotus supplied ECU. This was with the stock MAF. Most of our testing back in summer of 2006 was using a stock ECU and MAF. I think it was fall of 2006 we switched over to the EFI. I know some people get confused trying to follow the sequence of my ECUs. Stock. Reflashed from Ragnorak for a month. Reflashed from Lotus. New Lotus stage 3 ECU. EFI.

Once we had the EFI, we still did some more testing. We tested cams, headers, exhausts, intakes.... and found that the de-cat was good, headers not bad, and still the best result among the things we tested was the above intake. Not huge by any means, but better.

[Cali]

Originally Posted by Randy Chase

Yes and not a lot.

Thanks, Randy...

[Murix]

Originally Posted by GTsRasta

Finally somebody gets it. BLah blah blah

Seriously, why do you still care? Why so passionate about something you don't have? You need to find new hobbies.

[MaineLotus]

Originally Posted by Randy Chase

Once we had the EFI, we still did some more testing. We tested cams, headers, exhausts, intakes.... and found that the de-cat was good, headers not bad, and still the best result among the things we tested was the above intake. Not huge by any means, but better.

Musical ECUs

One more question, if you don't mind - Supercharged or NA? The reason for my question is - I think Supercharged with EFI/MAF (I don't think MAF can be used with EFI) will have different results with regards to intakes. Of course no one knows without testing...

[GTsRasta]

Originally Posted by Murix

Seriously, why do you still care? Why so passionate about something you don't have? You need to find new hobbies.

??? Go tell that to the Lotus-less Randy Chase while you're at it.

I troll through here because I hope to own a Lotus one day, just as I trolled through newcelica.org in the hopes that I'd get a Celica GTS one day. Now that I have my GTS, I hope to use that as a test bed for when I get a Lotus. That's all. What's the problem with me surging interest in things? Was the PPE race header that I brought back the interest to here that bad of an idea? Whatever.

Why do I care? I answered that in the beginning of the thread. It's because I thought it was just absolutely STUPID for certain vendors to be praised with magical bolt on mods that will undoubtedly give power while others get flamed with the "lotus ECU will unlearn the gains" BS. The intake argument is up in the air without any supporting mods to go along with it, but I'm pretty sure I fleshed out the header part in this thread for good.

Woes me for not finding that magical dyno graph where a breather mod showed 100% power loss in all RPM ranges...I did this site suchhh a diservice...

[Randy Chase]

Originally Posted by MaineLotus

Musical ECUs

One more question, if you don't mind - Supercharged or NA? The reason for my question is - I think Supercharged with EFI/MAF (I don't think MAF can be used with EFI) will have different results with regards to intakes. Of course no one knows without testing...

All of this was before I was SC. To add to the timeline, we installed the SC in August of 2007. At this time we still had the above intake on and did change headers to a 2bular made for the SC. We considered then testing a cold air intake and also a throttle body for the SC but then I sold the car.

There were other things to test post-SC, but I never got around to them.

[MaineLotus]

Thanks!

[charliex]

Heres a diagram on why a CAI might lose power. The spark advance tables are also the same.