Maddawg

Hey peeps i used to own a 2005 civic ex sedan. I just sold a lot of my toys including my 2008 tundra crewmax and bought me a 2007 civic si sedan. I keep looking up videos to choose a exhaust. People keep saying you can run the car in VTEC all day. is this a button that i need to push or are they saying just running in in the 6-8k rpm range? I noticed that when i hit high rpm the car kinda takes the hell off again going with a SRI and a skunk2 i think. I really just want a deeper sound since i had 40 series flowmasters on my truck

Maddawg

I just read through the forums and people say they are putting premium fuel in the SI. I just filled the tank with 87 did i mess it up or will it just run a little slower with the low grade?

hath33

iTrader: (1)

No putting 87 wont do anything serious. but if ur owners manual says to put premium i would sugest to follow wat it says but putting regular in one time wont hurt it. there is no button for vtec either im not sure how vtec works but i know there is not a button lol

MelJ

SIs need premium because of its higher compression ratio. Newer cars have knock sensors to adjust for lower octane fuel usage. I don't think you did any harm though. I just wouldn't make a habit of it. Stick with what the manual tells you to use.

sdaidoji

iTrader: (1)

i believe in the fule door should be a recommendation of which fuel to use.
V-TEC is coded on the car, under cetain conditions it will engage. Not sure, but guess the 8th gen have different conditions than the 7th gen to engage.

gearbox

iTrader: (95)

yeah your ecu will correct the timing to compensate for lower grade gas, but you will also lose power. i would use premium if the owners manual recommends it for best performance. regular will not kill the engine but i wouldnt use it all the time.

MelJ

It's probably the same for the most part except for RPM range for engagement.

ajr12388

Vtec for 07 SI engages at around 6000 RPM. You should hear it open up and really pull you at that point.