The 2.0 liter had a 86mm bore and 86mm stroke. The 2.4 liter has a 87mm bore and 99mm stroke. The longer stroke is the reason the the red line is lower. Red line is directly proportional to stroke length.
New Civic Si
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Yeah, piston speeds on the longer stroke engines would be insane at the 8,000 rpm redline of the K20. An 8,000 rpm redline with a 99mm stroke is a piston speed of well over 5,000 ft/sec. As it sits with the 7,000 rpm redline, the piston speed is 4,547 ft/sec.
Even the S2000, with its 9,000 rpm redline, has a maximum piston speed of 4,960 ft/sec because of its shorter stroke (84mm). When the S2000's engine was upsized to a 2.2L (with a 91mm stroke), the redline was reduced to 8,200 rpm. Piston speeds were still 4,896 ft/sec.
Handy piston speed calculator link
Even the S2000, with its 9,000 rpm redline, has a maximum piston speed of 4,960 ft/sec because of its shorter stroke (84mm). When the S2000's engine was upsized to a 2.2L (with a 91mm stroke), the redline was reduced to 8,200 rpm. Piston speeds were still 4,896 ft/sec.
Handy piston speed calculator link
Yes, I did the piston speed calculations too. That's pretty insane for a stock engine. If you consider that fuel cut is actually 7200 rpm, peak piston speed goes up to 4650fpm. Hondata has a reflash that brings fuel cut to 7600fpm which is 4920fpm. I don't think longevity is going to be a problem though as material science has evolved enough to handle this.
One thing I am interested in is that Honda stated that in order to get the fuel mileage figures this thing is getting that they were able to reduce friction in a lot of areas. I am interested in exactly what they did. The ring back is usually where the most friction is so I'm specifically interested in this. I'm sure the information will come out as time goes by.
One thing I am interested in is that Honda stated that in order to get the fuel mileage figures this thing is getting that they were able to reduce friction in a lot of areas. I am interested in exactly what they did. The ring back is usually where the most friction is so I'm specifically interested in this. I'm sure the information will come out as time goes by.
Yep, same with the CR-V. It took a large fuel economy jump, from 21/24/28 in 2011 to 23/26/31 in 2012. They also cited lots of friction-reducing technology in the engine. That's a 9.5%/8.3%/10.7% improvement in the fuel economy numbers.
Interesting to look at modern stuff compared with old technology. My first car was an Olds Cutlass with a 307 V-8 engine. It would upshift, floored, at about 4,800 rpm. And it had a rather short 3.385" stroke (86mm). That's only 2,708 ft/min!
And sorry...all of the ft/sec units in my previous post should be ft/min.
Interesting to look at modern stuff compared with old technology. My first car was an Olds Cutlass with a 307 V-8 engine. It would upshift, floored, at about 4,800 rpm. And it had a rather short 3.385" stroke (86mm). That's only 2,708 ft/min!
And sorry...all of the ft/sec units in my previous post should be ft/min.
Originally Posted By: Hokiefyd
Yeah, piston speeds on the longer stroke engines would be insane at the 8,000 rpm redline of the K20. An 8,000 rpm redline with a 99mm stroke is a piston speed of well over 5,000 ft/sec. As it sits with the 7,000 rpm redline, the piston speed is 4,547 ft/sec.
Just how many miles are on this car's pistons, sir?
Yeah, piston speeds on the longer stroke engines would be insane at the 8,000 rpm redline of the K20. An 8,000 rpm redline with a 99mm stroke is a piston speed of well over 5,000 ft/sec. As it sits with the 7,000 rpm redline, the piston speed is 4,547 ft/sec.
Just how many miles are on this car's pistons, sir?
Dyno blue was a choice I was considering with mine too, but Taffeta white won me over as usual. I just love white cars. The 2012 I was considering was a Taffeta white SI sedan.
Originally Posted By: Hokiefyd
Yep, same with the CR-V. It took a large fuel economy jump, from 21/24/28 in 2011 to 23/26/31 in 2012. They also cited lots of friction-reducing technology in the engine. That's a 9.5%/8.3%/10.7% improvement in the fuel economy numbers.
Interesting to look at modern stuff compared with old technology. My first car was an Olds Cutlass with a 307 V-8 engine. It would upshift, floored, at about 4,800 rpm. And it had a rather short 3.385" stroke (86mm). That's only 2,708 ft/min!
And sorry...all of the ft/sec units in my previous post should be ft/min.
Well, you were dealing with an engine that had a small cam, small head ports, leading to a torque an HP peak that happened at such a low RPM, that going past 4,800 RPM was pointless.
Also, there are two other things determining the maximum piston speed, weight and strength of the individual components.
Yep, same with the CR-V. It took a large fuel economy jump, from 21/24/28 in 2011 to 23/26/31 in 2012. They also cited lots of friction-reducing technology in the engine. That's a 9.5%/8.3%/10.7% improvement in the fuel economy numbers.
Interesting to look at modern stuff compared with old technology. My first car was an Olds Cutlass with a 307 V-8 engine. It would upshift, floored, at about 4,800 rpm. And it had a rather short 3.385" stroke (86mm). That's only 2,708 ft/min!
And sorry...all of the ft/sec units in my previous post should be ft/min.
Well, you were dealing with an engine that had a small cam, small head ports, leading to a torque an HP peak that happened at such a low RPM, that going past 4,800 RPM was pointless.
Also, there are two other things determining the maximum piston speed, weight and strength of the individual components.
Those 307's were so horribly slow!
Originally Posted By: SLCraig
Dyno blue was a choice I was considering with mine too, but Taffeta white won me over as usual. I just love white cars. The 2012 I was considering was a Taffeta white SI sedan.
I was set on the gray until the last literal second. We got financing all set, etc. I said I wanted to go out and look at it one last time. They had a blue one parked next to it and something in me just said, "get the blue". I've never regretted that decision it's such a nice color.
Dyno blue was a choice I was considering with mine too, but Taffeta white won me over as usual. I just love white cars. The 2012 I was considering was a Taffeta white SI sedan.
I was set on the gray until the last literal second. We got financing all set, etc. I said I wanted to go out and look at it one last time. They had a blue one parked next to it and something in me just said, "get the blue". I've never regretted that decision it's such a nice color.
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Originally Posted By: Scott_Tucker
Those 307's were so horribly slow!
Yes, yes they were.
Those 307's were so horribly slow!
Yes, yes they were.
Nice car.
I think many car testers are not accurate because they spend too little time in the car to familiarize themselves with the controls and systems.
A lot of cars are better than their rag reviewers would say. I think yours is a great choice as an economical but still rewarding to drive car.
I think many car testers are not accurate because they spend too little time in the car to familiarize themselves with the controls and systems.
A lot of cars are better than their rag reviewers would say. I think yours is a great choice as an economical but still rewarding to drive car.
Its a flop, just like the 02-05 Civic Si was. The 06-11 Si was a much more fun car to drive and handled better. The new one does not have that nice revving engine and the suspension is too soft.
Hopefully Honda kills it with fire soon and brings back a car worthy of the Si badge.
Hopefully Honda kills it with fire soon and brings back a car worthy of the Si badge.
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That SI is boss! I've always had SI envy. I got to test drive an 07 and it was tough to drive slow...the car just wanted to run!
I bought a Corolla XRS in 04 (still have it). I wish I knew Honda was planning a 4 door SI back then...
I bought a Corolla XRS in 04 (still have it). I wish I knew Honda was planning a 4 door SI back then...
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