Yes, you do have a speed limiter on your 07 si. I can't remember exactly what speed it's limited to, but I think the 06's were around 150 whereas the 07+ is around 135.

If you would like to get rid of the limiter (and don't care about your warranty) then you can get the hondata reflash, but it's only recommended after i/h/e are installed. The reflash will remove your speed limiter, smooth out the power band, lower vtec engagement to around 4k rpms (instead of the stock 5800), and bump up your rev limiter to 8600 rpms (I do believe).

For more info on the reflash hit up www.hondata.comand check it out. Sorry I don't have specific information, I don't own the car so exact numbers aren't that important to me. If you'd like to know anything else about it feel free to ask.

 

Thanks. That was very helpful. 135 is plenty fast enough for me. Bottom line is that I do care about the warranty, but it's nice to know that 1) there is a limiter and 2) that there is a way around it if I ever lose my mind and want to give up the warranty so I can go 150+.

 

No problem man.

 

i dont think the car can go 150. i saw a test where they reached 150 but they did but they didnt consider the air resistance.

 

True Cyberex. Just because the engine and gearing are theoretically capable of 150 doesn't mean the car is going to make it. Wind resistance/aerodynamic flow is the ultimate top-end limiter. As I recall, the reason for the development of the Cobra Daytona Coupe was because the Cobra with the AC Ace body had topped out due to its aerodynamics. The engine was capable of more, but it couldn't push the body any faster. Hence, the more aerodynamic Daytona.

The other end of aerodynamics is that the engine can push the car, but pushes it fast enough to turn the whole thing into a wing and take it airborne. Some famous flips of LMP cars at Atlanta because they turned into virtual wings. What was to be the next step in the development of the Ford GT in the late 60s was abandoned after it showed a tendency to fly and killed one test driver.

 

I wouldn't be suprised if one that was highly modified surpassed that, but in stock form you are 100% correct. I think in the test I saw they got it up to 144 or something, which (as ruhdwulfstated) the k20z3 doesn't have enough power to push it pass that because of aerodynamic restrictions.
With that being said I've been in quite a few cars that weren't aerodynamic in the least bit above 140 mph.. Srt's, sti's, evo's, etc.

 

Cross posted from the 1/4 mile time thread... but it may shed some light on the top end and electronic speed limiting. Good information in any event.

Here are the results of some Road & Track tests.

2006 Civic Si
http://www.roadandtrack.com/article.asp?section_id=3&article_id=2942

2007 Civic Si "Pocket Rocket" Comparison
http://www.roadandtrack.com/article.asp?section_id=36&article_id=5247

Data Panel
http://www.roadandtrack.com/assets/download/0607_pockets_dp.pdf

The data panel is for the "Pocket Rocket" Comparison test and includes the 2007 Civic Si in addition to the Mini-Cooper, Mazda Speed, Toyota Sentra, and VW GTI.