Can a Superchagered Z28 have a lumpey CAM, and sound like a NA heads and cammed LS3
 

Can a Superchagered Z28 have a lupey CAM, and sound like a NA heads and cammed LS3?

I heard a LS3 with a lopey cam and it sounded awesome!
Can the Supercharged Z28/LSA have a lupey cam also?:readthethread: :word::paddle:

With forced induction you do not want too much overlap(which is what causes that lopey idle).

No offense, but to me, you post isn't clear?... It would seem to me that other than a possible supercharger whine, it should sound somewhat similar. You have to understand the design of the exhaust would have to be identical to the LS3 you've heard. I think under throttle the supercharged engine will sound different though.

I believe that overlap allows cylinder pressure to bleed out before the valves close.

With a supercharger too much overlap will cause the incoming fuel and air to be pushed out into the exhaust. With a turbo the high exhaust pressure will force exhaust back into the cylinder.

basic question.... can a supercharged motor sound like a N/A motor....

yes and no. it can be made to sound the same, but why would you want that. you can have a supercharged motor with a lopey cam, but making it sound the same will be an entirely different story.


as for lopey cams...

**Lobe Separation Angle**(LSA)

The LSA of the car is the difference, in degrees, between the point of maximum lift on the intake lobe and the point of maximum lift on the exhaust lobe. This number can vary greatly, and it again depends on your goals for the car. Most cams come with an LSA anywhere in the range of 104-115. If you are simply looking for a cam based on the sound it produces, this is what you want to look at. A lower LSA, such as a 108, will produce a much choppier and aggressive grind then say a 114 LSA. However, there are many other factors that the LSA will effect when it comes to engine performance. A low LSA will result in more torque in the engine, but the torque curve will be wore peaky and not as flat/ stable as a higher LSA cam. This means that you will be making more torque at a certain RPM with the lower LSA, but it will fall off quickly. A higher LSA will produce a lower peak torque number, but you will be making good torque throughout the power curve, which is why even though a low LSA may sound good in a car, it is not ideal for a street driven car.

It is also important to note that numerically lower lsa is better for n/a power, and tighter numerically higher lsa is better for forced induction like nitrous or turbos since it will have less reversion and not bleed boost.

nicely said Spike

I have a feeling I know D-Unit from somewhere... lol

Hopefully that answered the question. Very nicely done. Spike

The Eaton supercharger used on the LSA motor has a vacuum actuator which opens and closes the boost bypass valve. This valve is technically adjustable, but is usually set so the bypass is always open until manifold pressure changes.

So until you really step on it your engine will idle, drive, and sound mostly like an N/A motor (especially at the tail pipe), and depending on the CAM profile/exhaust setup you hear what is expected. Also Eaton has this very quiet new design so even when its cramming air in the motor it is supposed to have less whine than an 03/04 Cobra. Over spun Eaton's on the Cobras do make some noise, but with the bypass open and an x-pipe with Borlas you're hearing exhaust note.

On the other end one who likes the supercharged sound might be tempted to change this so that the bypass is eliminated and they are in boost all the time.
*THIS IS BAD* Intake air temps will skyrocket, unless you have gallons coolant in the intercooler reservoir and buckets of ICE in it as well. And even then the temps will still get up there (160+f) eventually (My bypass valve broke, $200+ part!!).

Kenne Bell and Whipple twin screw superchargers can be much louder of course even at idle (my 17psi KB pulley setup was pretty loud at idle, but nothing compared to the exhaust).

what about methanol injection? :thumbup:

geese spike I read post 6 and I thought to myself "geese this guy obviously has experience with a boosted vehicle" then I read about overspinning eatons and heat soak and incresed IAT II temps. and my first though was Meht injection. but you said it already. so now that you stole my thunder in 2 posts I'm going to have to send you spam mail. just playing. in all honestly I just wnated to say couldnt agree more. :)

i'm hoping to be the 1st supercharged SS/RS!!!!:headbang:

i'm pushing East Coast Supercharging to work quickly on a Camaro kit...

if that doesn't happen fast, I'm going to do a cam, headers, cai, etc by summertime..(not very patient)


if more folks e-mail then maybe they'll get things rolling quicker;)

www.eastcoastsupercharging.com

:thumbsup: