Valve Springs: does acceleration increase?
 

I was wondering if the stock springs are replaced with heavier ones Does acceleration increase ?

I'm guessing if there is a good air/fuel mix with a good spark plug then acceleration will increase.
I mean it isn't like we are turning it by hand besides to start it.

i'm asking because when i give my engine a little over half throttle no more RPM is gained. i just don't want to lose any torque that can't be fixed with more throttle if that makes sense.

Or should i just get a different ratio rocker arms?

Springs do not increase acceleration. A stock spring is made to function within a certain perimeter. A stock spring for instance will work proficiently within a certain rpm range. When increasing the power band to higher rpm's the stock springs could cause valve float, or running a cam with an excessive lift can cause valve bind. One must be careful when choosing the correct valve spring for if too weak valves will eventually float causing the piston to contact the valve whereas if too strong the valves will beat themselves into the seats.

The other half of my question would be.. Do stiffer valve springs DECREASE acceleration?

Reread my previous post. The stock valve spring is designed to work with a cam up to certain cam specs ( lift& duration). Once you move outside the stock perimeters of the cam you must upgrade the springs to match the new cam spec. It amazes me when I read on a site that the spring they were selling would help increase performance. The spring alone will not help performance unless matched with the cam. Kinda like if your shoe size is a 10. If you buy a size 12 or 9 you will have problems.

For a straight answer , i will answer my self.
Answer: The 18 pound springs don't hinder acceleration.

Lighter (not cheaper) may free up some HP in larger displacement engines. It wouldn't do anything noticeable to a 150cc. It can help a built engine perform at its maximum but the spring itself really adds negligible HP.

Back in the 1970's when I built engines (ha, Ford 390 FE big block, 427 Med riser heads dual quads, etc in my 1969 Torino GT fastback), they used to have a graph of different combinations of cams/valve springs and the rpm range they worked thru ... handy thing to have ... I'm sure those exist for todays gearheads also right?

scanned polaroid 1979 my dads garage in Warren Michigan, I was 17 and knew "everything" ....
I did everything myself, just had a basic Ford service manual, oh and 3 doors down the "Murray brothers" who raced locally.
https://lh3.googleusercontent.com/-0...al%2Bquads.JPG

Here, OP read this link to educate yourself
http://garage.grumpysperformance.com...lve-train.181/

Thanks, i really do appreciate this. I'm reading through it now.

edit: most of it i don't need to know yet but thanks for the info. and wow i bet your Torino was a monster with dual quad carbs with a 390 combo.

Why am I alive today? ...
The good lord wanted me to get past my crazy stage, get married and have kids of my own, that's the only way I can say it.
Having that much hp (true 450) in a car weighing less than 3200 lbs with a 4.11 rear end is not responsible for a 17/18 year old.

Back to cams/valve springs.... fun stuff, though for now on my basic 150cc go kart I'll keep it stock except minor stuff. My boys ages 10/12 it's enough for them now.

Good luck on your journey.