[slacy]

Check this out -- a paper published by the SAE (Society of Automotive Engineers) written by the developers at Toyota (and Yamaha!) of the 2ZZ-GE:

http://www.c7performance.com/resources/2zz_ge_article.pdf

As well as this magazine article about VTEC vs. VVTL-i (circa 2000)

http://www.c7performance.com/resources/vtecvsvvtli.pdf

Steve

 

[Knute]

Great paper on the 2ZZ-GE! Thanks for posting the link.

Reading through it, I noted on page 7 of the pdf the following comment:

"The oil pan itself is without a baffle. This quickens the return of oil into the oil pan, increasing performance. Air suction was minimized by optimally positioning the suction pipe inlet. The 2ZZ-GE can withstand 1.0G without sucking air"

Uh oh!

I have seen reports, and also heard it mentioned at the show by Lotus staff that the standard suspension Elise can sustain 1.0G, and with the LSS, even higher. I hope they added a baffle...

Did I hear a rumor that Lotus changed the oil pan as part of making the engine fit the Elise?

-Knute

 

[Randy Chase]

I had read that Toyota redesigned it for that reason in...umm... 2002?

 

[Hartmut]

Hi Slacy

Thank you for these links, too.

Did you see the torque curve (figure 10 )?

Please red this :

http://www.pistonheads.com/doc.asp?c=108&i=7964LOTUS 111R

In short :
Performance could almost be described as not enough and then too much!

But perhaps tuners will succeed in filling up that valley at 6000 RPM.
(Possibly some supercharger will do the job)

Hartmut

 

[Evl]

I wonder if they chose the cam changeover point for marketing reasons. To give people the feeling of a kick in the butt when they change over. It seems to me that from the pure performance point of view, you want to maximise the integral of your torque curve, and you should change over at the point where the two cams produce the same power.

I can think of only two reasons not to do this: 1) The operation would be so smooth as to be un-noticeable, and 2) you would increase wear on the high speed cams.

Does anyone know the actual reason?

 

[vvtlikick]

...
Did you see the torque curve (figure 10 )?...

In short :
Performance could almost be described as not enough and then too much!
...

The graph's scale exaggerates the variance in torque output over the rpm range.

There's this myth that the 2ZZ-GE is ridiculously weak below 6000rpm, which isn't true.

I made a spreadsheet comparing torque per liter at the wheels for a stock Celica GT-S dyno to a stock Maxima 3.5L (supposedly a torque-monster).

Below 4000rpm, the GT-S is around 10% weaker for its displacement. About 4000rpm, the GT-S climbs to equal the Nissan, then drops off about 5%. Past 5000rpm, the Nissan output drops like a rock.

And compared to a RSX-S, the GT-S is almost equal. The RSX-S torque advantage comes from larger displacement, not superior tuning.

 

[vvtlikick]

I wonder if they chose the cam changeover point for marketing reasons
...
Does anyone know the actual reason?

So far, the tuners that have experimented with moving the VVT-L engagment point on mildly modified 2ZZ-GE's haven't found any increases in power. So, it would appear that you'll need more mods (like new cams) and/or more dyno tuning to make moving it worthwhile.

Here's Monkey Wrench Racing's take on the issue:

Article
Dyno chart

 

[Hartmut]

Hi vvtlikick, Joe McCarthy and the rest of interested experts out ther in the WWW

After all I have been informed so far about the Honda K 20 and the Toyota 2ZZ-GE I got the impression that their mechanical and electronical valve steering systems seem to be very similar.
(Please correct me in case I am wrong and explain the differences).

Nevertheless I got the impression that a Honda engine seems to be the better choice in case somebody like me wants to get enough horses into his Elise to reach at least 270 km/h or 170 mph on an German Autobahn (I guess: approx, 320 of them at the top will be sufficient for this top speed)
The other differences in between these 2 engines certainly are bore and all those engineering margins provided by Honda and Toyota engine designers in their mechanical lay out and also how much they felt confident about these margins when mapping their different ECU.

These margins or say “bottlenecks “ in the engine lay out are decisive for the top power output in other words the max. combustion air pressure / temperature values still allowable for a certain lifetime of the tuned 300 + hp engine.

But besides the reliable top power of more than 300HP I also would like to have a torque curve, which does not show such bumps, valleys or potholes, as I saw in the different torque curves of both engines so far.
The curve I would like to have should look very similar to that one drafted in Joe`s homepage. In other words -I feel sorry for my English- :

I do not want to have an engine which behaves as if it had some old fashioned exhaust gas turbocharger becoming active only when RPM has reached already the 6000 value.

Which tuner will be the first to help me out in this dilemma ?

Joe if it is you please also let me know what `s the chance that your supercharged Honda engine will be street legal one day over there in CA., where you have these stringent emission limits.
I guess this still will be a very difficult task for you. too.

Cheers

Hartmut

 

[vvtlikick]

Hi vvtlikick, Joe McCarthy and the rest of interested experts out ther in the WWW.
...
Nevertheless I got the impression that a Honda engine seems to be the better choice
...

Hello.

Right now, the Honda engine would be a better choice for big power numbers (like 300hp+). For one simple reason ... superior aftermarket support.

Although Honda's K-series is even newer than Toyota's ZZ-series engines, the Honda's are inheriting the popularity of Honda's discontinued B-series.

The expanding applications of the 2ZZ-GE should improve its aftermarket, but we'll have to wait and see.

I'll add check out http://clubrsx.com or http://newcelica.org/ for info on the two engines' potentials.

 

[Joe McCarthy]

It's good to see someone is taking the time to tune the 2ZZ-GE.
I'm working in close conjunction with Hondata, who are able to actually tune any of the over 60,000 lines of code in the K20A ECU, which is a far superior method to adding piggy-backs.
We've been able to bring VTEC into play as low as 3,000 RPM with excellent torque increases, and have a variable VTEC engagement mapping that isn't just RPM dependent, but also takes into account the MAP sensor signal. This way if you want VTEC at a lower RPM you only need to put your foot into it a bit farther, while at a light load cruise you don't have to engage it to improve fuel economy. The VTEC window in my exclusive K20A Elise mapping extends from 3,800 to 5,600 RPM and everyone who has it simply loves it.
We've been investigating supercharged and turbocharged options lately with the addition of Nitrous Oxide. Take a look at www.hondata.com if you'd like to see some impressive torque curves.
Joe