Hey Adam, how do ya like this dyno chart?

[srivendel]

This one seems more believable:


The Si is still putting very respectable power to the wheels. A loss of 21 hp (197 to 176) is only around 11%. I wonder if that electric power steering has anything to do with it?

S.

[MadMerv]

What is the deal with that drop at 5600, then the surge of power at 5900-6300? Is that normal with a VTEC? It's like it starts falling on it's face, then gets a shot of NOX! Very broad torque curve, though.

[srivendel]

Yes, that's the VTEC effect. It feels very much like a turbocharged engine in that regard. That big power hit, coupled with an 8,000 rpm redline, gets fairly addictive in short order.

The flat torque curve is a new thing for Honda, and it really improves around town driveability. You don't have to beat the crap out of the engine to make rapid progress, but that glorious VTEC song is available when you need it.

It's certainly not a perfect way to distribute power from a pure performance standpoint, but it helps balance fuel economy and power in a useful way for a real world car.

S.

[altiain]

It's certainly not a perfect way to distribute power from a pure performance standpoint, but it helps balance fuel economy and power in a useful way for a real world car.

S.

Let me know how your fuel economy turns out in real world numbers. I used to average about 18mpg in mixed city/highway with my H22a (2.2L, 200hp, 156 lb-ft of torque) VTEC Prelude.

[srivendel]

I will. Most of the car rags have been getting around 24mpg during their tests, so that bodes well, I think.

Merv, this is how C&D described the switch-over:
Honda worked to intensify the cam switchover at 6000 rpm, and it now feels as if someone had flipped a switch and turned on some hidden power source, and there's nothing subtle about it. Adding to the change in character is a tuned air intake that tunnels out of the engine compartment, into the fender area, and back to the intake manifold. By routing the intake through the fender, the sound of the engine switching to high-revving cams is amplified because the fender acts as a resonator. With the driver's window down, the switch*over sounds like a karaoke version of a Ferrari V-8 aria.

S.

[Adam Payrot]

Very nice, and much more believable :)

Iain, I get 24mpg and I hit vtec quite a bit... lol

The window sticker for the Type-S says 23/31... I averaged 31mpg for the entire drive to and from Florida, and back down to 23-25 in the city. I'm glad that I get the advertised numbers, under 20 would suck

[Adam Payrot]

I'm wondering what the difference between the Si and Type-S VTEC system is (based on that description). I was impressed on the test drive of my car, the crossover felt nothing like my friend's GSR-swapped hatch, even before he added electronics. It's very smooth (supposedly it is w/ all iVTEC's) and doesn't really feel like the turbo effect of the earlier VTEC engines.

[srivendel]

The window sticker for the Type-S says 23/31

Those are exactly the numbers listed on my window sticker.

S.

[Adam Payrot]

Compare that chart to mine, and you see that the RSX doesn't fall off at VTEC crossover. Looks like the Si has the more typical VTEC feel to it .

[srivendel]

Compare that chart to mine, and you see that the RSX doesn't fall off at VTEC crossover. Looks like the Si has the more typical VTEC feel to it .

Yes, and the hit is also much bigger. You're jumping from 130 to 145 between 5800 and 6200, whereas I'm jumping from 125 to 160. Interesting. I'll look forward to getting my Si on the same dyno you used.

S.

[MadMerv]

Yes, and the hit is also much bigger. You're jumping from 130 to 145 between 5800 and 6200, whereas I'm jumping from 125 to 160. Interesting. I'll look forward to getting my Si on the same dyno you used.

S.

I would gladly give up that little drop just before VTEC for that early torque build up. Can't wait to see how your dyo run compares to Adam's.

[RX7-2nr]

Compare that chart to mine, and you see that the RSX doesn't fall off at VTEC crossover. Looks like the Si has the more typical VTEC feel to it .

honda worked purposly smoothed out the surge on the K20A in the last gen Si and the RSX. people missed the typical VTEC feel, so Honda brought it back in the K20Z.

[Adam Payrot]

honda worked purposly smoothed out the surge on the K20A in the last gen Si and the RSX. people missed the typical VTEC feel, so Honda brought it back in the K20Z.

I have a K20Z K20Z1, fwiw. The new Si is a K20Z3

[Sharpie]

Shoulda just boosted your miatas, I got 27+ on this last tank. 22 mile commute, about 10 in town, and 12 hwy.

[Nexus Flux]

I average about 26.5 mpg. That's about 75% city and 25% highway, and the VTEC does get a workout.

[Adam Payrot]

Shoulda just boosted your miatas, I got 27+ on this last tank. 22 mile commute, about 10 in town, and 12 hwy.

Can't finance boost

[RX7-2nr]

I have a K20Z K20Z1, fwiw. The new Si is a K20Z3

hmmm. i wasnt aware of the change from the k20A2. did they do that when they upped it to 210hp?

[Adam Payrot]

hmmm. i wasnt aware of the change from the k20A2. did they do that when they upped it to 210hp?

Yeah, the major differences between the A and Z were the cams, the Z has the Type-R cams and is a little closer to being the Type-R motor, K20A (the K20A US engines all have a number behind them). It still doesn't have the higher red-line or the extra 20hp or so of the Type-R.

[srivendel]

And the Si mill gets a balance shaft but loses the power steering pump for electric power steeting. It also gets the Type R's LSD.

S.