Sorry, I was looking aroiund the site and couldn't exactly find the answer i was looking for, so could anyone tell me how much HP the si has BEFORE vtec kicks in?

I was thinking it'd be in the 150-160 range?

 

look at dyno charts. it varies by car and dyno, etc.

 

Looking at my chart it's about 112whp to 123whp between 5000rpm and 5800rpm. But that's on a Mustang Dyno with a factored 20% loss to the wheels. So at the flywheel it's about 140 - 154HP.

 

i think whp is more important to consider ... looking at a stock k20z3 i believe that 123whp is alittle low but vtec does make a difference ... good luck looking for a stock dyno chart

 

Yes I know that. I was just giving the guy the answer he requested.

And the power below Vtec is low for a reason. Believe it or not even though the Si is the performance flagship of the Civic line...it was still designed with fuel economy in mind.

 

well thats nice to know, i always considered the Si to be more then just a fuel economic vehicle ... but all k20s have I-Vtec which includes the VTC fuction so i guess its kind of obvious ...

 

this is a lil off subject but relevant to fuel economy, if im doing driving and its hilly and i better off stayin in lower gear meanin higher rpm and more power? or should i leave it in higher gear meaning lower rpm and less power but better mpg? btw im aiming for mpg.

 

Lower gear higher rpm.

You don't want to put too much load on the motor especially when going up hills. Imagine riding a mountain bike uphill in higher hear and how hard it is pedal. Now take the same scenario but in lower gear, you pedal faster but with less effort.

The little extra fuel you burn while in lower gear doesn't compare to the excess wear you'll undoubtedly put on your motor if you keep it in higher gears when climbing hills.

 

In reviewing my Dyno's (Dynojet), the WHP looks like it peaks at around 124/125 from 5,200 to Vtec (5,800), then jumps to around 168 from 5,800 to 6,700, then climbs to 189 from 6,700 to 8,200.

Course, everyones car is different.

 

^^ This my friend is very helpful and probably true for most cars as a general guidline. On the other hand for the Si as Fuel efficient...kinda laugh haha, being that the Si is the performance version...I drive it like the performance version...I can say my fuel economy is...."lower"

 

thats what i was thinking but i seem to be getting better mpg in 6th? the hills arent too steep so thats possibly why? when i drive i usually try to equate it to riding a bike, which is why i usually kept it at a higher rpm but if im gettin better mpg is it really "harder" on the engine?

 

is that stock? cant be

 

Crap, your right. The dyno I was looking at has my Greddy Evo 2 Catback and AEM Cold Air. Can't find my bone stock Dyno, hope I did not lose it.

Sorry for the mis-information, I thought this was my stock Dyno.

 

Check out where peak torque comes in and try and stay above that when going up hill. For instance my MS3 gets full torque at 3k so I keep it right above 3k so that I an not lugging my motor.

Lugging you motor = bad whether its going up hll or just going an a flat road.

 

still good to know tho

 

well if i were to have my rpms where the torque peaks, since its a honda i would hafta be in vtec which i know is unnecesary.

 

Bone stock 07 Si:

 

The torque is pretty even across the range. Peak torque is after VTEC engages, I wouldn't recommend driving at 6000+rpm to save gas.

 

Also look in your manual, it lists road speed shift points. Each speed provides a shift point right at 3k, that way you stay in the torque curve while keeping revs low.

 

i bought my car used and i didnt notice i didnt have the manual til after i left but basically keep it around 3k for cruising?

 

Make sure that after you shift you land at least above 2300. Look at the graph above. Just make sure that you're in the torque curve so you don't excessively load the motor.

 

Wow the car only lost 6 hp and 2 ft/lbs or torque to the wheels.

Really?

 

yea really.

 

doubt it. I've seen your posts....You should know better

 

hahaha i was messing with you.
usually its around mid 180's.
the car might have had an intake or something.
but i've seen a stock si pull those numbers as well.
but it was on the dyno at sea level during the winter.

and what do you mean you've seen my posts??