TRUTH/MYTH OF LOTUS ECU

[Chris Mackey]

Seems appropo.

[ZAMMY1]

excuse the ignorance, what is the "GPS" term in the diagram?
thanks, sam

[charliex]

GPS = Grams Per Second

[dstevens]

Our observation with the MAF based Honda ECUs is that any change to the intake system, and to a lessor degree the exhaust header, will alter the output of the MAF and generally screw things up. Even a small change well upstream of the MAF can cause turbulance and an incorrect signal. Most of the aftermarket has tried to match intake tube diameter only, without measuring the MAF output vs flow. We've found that switching to the regular MAP based system is better is most cases, which is an internal ECU 'operating system' change. Charlie's diagram has it bang on - especially the bottom left graph which shows the MAF output altered by the air intake.

[GTsRasta]

Originally Posted by charliex

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

Cool stuff with the fuel tables charlie. This is why the intake argument is the only one I'll accept.

[XPcarguy]

Originally Posted by xtn

An attempt to answer your question:

Why would anybody put a splitter or winglets on the front of a rear drive car? The fact is that the rear end might not have as much mechanical grip as the front end even on a front driver. So the fact that the rear end slides around will limit the speed the car is capable of in the turns. Adding a rear wing is one way to increase the grip where desired.

xtn

Downforce allows for dynamic balance. It is often desired to have a car that oversteers at low speeds but is neutral to mild understeer at high speeds. Through suspension settings alone, it's very hard to achieve that switch. Since downforce has a greater effect at speed, it allows for this result. One can setup a car to have greater front grip when the aero has little effect and then through the use of downforce makes the rear of the car more stable at higher speeds.

Another reason is that reducing lift at speed front and rear is generally accepted as a "good thing" to do. Most street cars settle for reducing lift but the Exige actually provides downforce. Still, this is a good thing.

[TimMullen]

Originally Posted by XPcarguy

Most street cars settle for reducing lift but the Exige actually provides downforce. Still, this is a good thing.

So does the Elise...

[timdavis130]

Thanks charlie. So the problem is that the MAF provides inaccurate/inconsistent readings when the flow dynamics in the intake change, and this prevents the ECU from being able to properly adjust fuel delivery.

[charliex]

Exactly.

Another way to explain is it imagine the speedometer, the speedo is set to show say 50MPH at 1000 rotations , something external modifies it to 500 but the cars still actually at 50MPH, the driver sees the speedo reading 25MPH and adjusts to 50MPH read, the external modifier changes the number of rotations again, and so on and so forth, its a feedback system.

The error may get worse and worse dependant on whatever the external modifier is doing, or it may settle down.

Headers will do whatever they do, but i think they'd do better with a custom tune.

Anything that modifies the VE or AF mix is a potential for upsetting the ecu balance.

[lotusforsale]

Originally Posted by 06_Exige

GTS -

I applaud you for having the courage to say what you mean and mean what you say. I support your efforts in battling the midget mentality that some are stuck with. Most everyone here are enthusiats from what I gather. And those who try to diminsih your enthusiasm for the sport are questionable.

Horsepower, supercharged, turbo, header, intake, exhaust, vender, etc., etc., etc. can be debated for whatever motives. I have a Race header, Race intake, Larini SE exhaust, and K40 Radar System with Laser Jammer installed on my 2006 Lotus Exige. My goal is not to prove you right or wrong or anyone else here. Instead, I am a Lotus enthusiast who loves the sport, loves the car, and the people involved.

Myself, I take pride in driving a Lotus Exige, spanking Mustangs, Vettes, and their kind. I roll up to the red light and all eyes are on me. I rev up the Exige and others take notice. To me, that is what it is all about! Plus, the hot babes who scream out their phone numbers always gets a smile on my face!

I win car shows wherever I go. When I get there, there are 50 Mustangs, 25 Vettes and all the rest, yet there is 1 Lotus - MINE!.

We can measure performance in many, many ways. But criticizing you, or the next man for whatever reason is simply diminishing the sport. Most everyone here is an enthusiast, and for those who are not, then it is revealed in their postings!


P.S. I have owned three Vettes before moving up to the superior Lotus. I owned a 1982 Collector's Edition (telling my age), a 2001 Z06, and a 2006 Vette. I would never trade, sale, or accept anything besides a Lotus!

You're spanking Vettes and Mustangs in stop light drags with an N/A Exige? Really? Maybe if there's a bend in the road, but going straight? U sure they knew they were in a race?

[GTsRasta]

Thanks for the compliments, and VERY sexy Exige!!! I hope to own a NA 06 one day as well.

I think it's cool you have pride for your car, I'd wish for the same thing, and not just in one aspect. As for SPEED...I don't see how a car that only needs 350 whp to hit low 11's @ 130 mph is a bad platform

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Forcedfed is S0O0O0 not cool now that they went and took that Elise to the drag strip...just like those MR2-Turbo guys...curse them for wanting power in a midship... .

Anyways...I'd love to see a before and after drag strip run of stock Lotus that upgrades to a intake (and breaks it in after "X" amount of miles). That will ONCE AND FOR ALL solve the mystery of whether the intake "slows" you down, or makes your car faster. Good evidence that this test might work is the AEM CAI vs Injen CAI for Celica GTS's. I think I read once that back when the forced induction moderator for newcelica.org was NA, he noticed a drop in quarter mile trap speed after switching from his top end oriented Injen CAI to the low-midrange oriented AEM CAI. The comparison for the Lotus would be the stock intake vs an aftermarket intake instead...preferably one that has a 2.5" tube like stock that won't throw codes...like the weapon r one.

I mean...the DYNO proven answers as to whether they make power or not are thrown out the window with the stock ECU making adjustments...why not have a real world physical test?

[apk919]

Originally Posted by 06_Exige

0-60 or 1/4 mile has a LOT to do with driver skill. Anyone fool can put the pedal down, but the skill in shifting decides the winner. I get countless kids who try the Lotus; however, more often than not I show them who is the BOSS. My Vettes spanked the Mustangs - yeah, I slept well at night knowing it. My Lotus is comparing apples to oranges. I have smoked motorcycles with my Lotus Exige.

Those Ford boys are a dime a dozen (cheap), and those Vette boys are nose heavy. Sure, we can shove a 1,000 horsepower engine in a 1972 Chevette. And it would smoke anything from streetlight to streetlight. But when the smoke clears and dust settles...which would you rather have: a 1972 1,000 horsepower Chevette, or a new Lotus Exige?!?

Wow, what can I say?

BTW, that round thing coming out of the dashboard right in front of the driver's seat? It's a steering wheel. You can use it to make the car turn left and right. Most people who own a Lotus find it one of the more useful and satisfying parts of the car. Give it a try sometime... you may enjoy it!

[xtn]

I've only ever tried it once, because I was scared for my driveline components, but the Lotus, N/A or otherwise, can launch it's ass off. It would be easy to out-launch most mustangs or corvettes unless they've got super-sticky drag radials or slicks.

xtn

[GTsRasta]

Originally Posted by 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



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!

I had a talk with my Lotus Elise owning buddy today...and we had a little conversation about race headers, particularly the PPE versus the Weapon R. So I decided to look something up again...and this Weapon R race header link seems to have been deleted from the site!

WTF happened?!?!?!? How come it was deleted instead of it at least being locked for whatever reason?!?!?!?

[andykeck]

Originally Posted by GTsRasta

I had a talk with my Lotus Elise owning buddy today...and we had a little conversation about race headers, particularly the PPE versus the Weapon R. So I decided to look something up again...and this Weapon R race header link seems to have been deleted from the site!

WTF happened?!?!?!? How come it was deleted instead of it at least being locked for whatever reason?!?!?!?

Seller is not a sponsor?

[GTsRasta]

Dustylax's dyno day thread, Mahle forged piston sale thread, and his moroso oil pan sale thread are still up! So that can't be the issue...

[GTsRasta]

Hmmm...I guess the new vendor forum rules have come into effect...and that mightttt be the reason his whole thread got deleted...along with the dyno graphs, race header reviews, and race header comments...

I just got hit with a warning about showing you guys the cheapest Weapon R shorty header price you can get shipped to your door after a simple Google Product Search search. Hopefully, that thread doesn't get deleted...I really didn't have any ill intentions whatsoever..

But wat about the other threads he made, showing that he's going to sell Mahle forged pistons and the moroso oil pan? Why didn't those get taken away if he wasn't an official vendor here? And if it's necessary to be a vendor here...why did the whole thread get deleted instead of just being locked? I was going to look up something about the header in that thread!

Anybody?!?!?

[robains]

I went from 247 WHP to 255 WHP with my ForcedFed PowerPak using FF intake (includes MAF) over a period of 4,000 miles. So it would appear the stand alone EFI unit was able to learn additional HP or Casey at FF worked some magic I didn't know about.

FYI, pre my FF PowerPak kit, I had just the Arqray Twin exhaust (muffler) running from stock Cat -- it showed 4 WHP gain on stock ECU -- was it noticeable, no, not at all. I don't know much about what a Stock ECU can do, but it seemed to be able to deal with exhaust add-on.

My personal opinion is that CAI's are NOT significant because once the air reaches the chamber it is NOT gonna be significantly cooler to make any real difference - certainly NOT cold. Where CAI may adjust HP is either because of better air flow characteristics and/or different MAF readings which could affect ECU for positive or negative results.

When I did a lot of testing with CAI for my Cobra while on the dyno, it turned out that the position of the MAF made a difference -- we did many dyno runs (time consuming process becaue you have to wait between runs to get temps back to consistant start point) and turned the MAF tube 30 degrees at a time -- to our surprise there was actually a sweet spot. But again, we're talking at most 3-4 WHP (on a car that was putting out 280 wHP -- just not significant. Only reason we bothered is because I was racing the car.

Nice diagram Charlie.

[charliex]

yep the positioning of the maf sensor is where it all comes into play, you can cheat and make the car look better on a dyno by changing the pattern of the MAF output, since it'll alter the fuel and spark output, but it changes elsewhere and can upset the driveability.

Had exactly the same thing working on the last SC kit, rotating the MAF sensor made it go from bad to great, its al about where that sensor picks up the airflow and the air flow pattern.

For the most part CAI's just seem to be of the its louder, so therefore its faster variety, i am sure there are some that do help, the red mushroom one from K&N seems pretty good and i think its around $100.

[GTsRasta]

I think the only way to know if it makes a difference for sure is if we compare drag strip timeslips from somebody who did a bunch of runs stock, and after he/she got a CAI for a while to let learn and acclimate to the Lotus ECU.

Celicas turn from consistant 15.0 second flat cars stock to consistant 14.9 cars and lower with a CAI. The same physical test can be done on a Lotus as well in order to know for sure if most of the CAI's made are just noisemakers rather than power adders.