ty_ty13

iTrader: (42)

when a cam has a "+x" after the specs what does that mean?

IE- "+2"
IE- 224/228 .590/.604 114lsa +2

what does that +2 mean?

if you install that cam dot to dot as in on 0* does that mean the cam has been retarded or advanced?

thanks,

Tyler

04gtoBMXracer

iTrader: (26)

114 lsa +2degrees advanced

EDS01SS

iTrader: (30)

from what i have read on here and i may be incorrect on this but the +2 is the amount of advance that was ground into the cam and aligning the dots is correct to recieve that advance.

ALLBOTTLE

iTrader: (13)

If you install it dot to dot that would mean the cam is 2* advanced.

ty_ty13

iTrader: (42)

does advance bring the power curve down or up?
same goes for retard- what does it do?

ALLBOTTLE

iTrader: (13)

retarding the cam gives you more peak hp, advancing will give you a broader powerband. Most cams are ground to make the most of the valve events to give you the best of both worlds.

PREDATOR-Z

Are you speaking of a certain pattern cam or in general?

Try this 230/228 .592/.588 111-1

What do you see in the valve events VS the same cam on a +4?

ALLBOTTLE

iTrader: (13)

I was speaking in general.

On this specific cam the +4 will give you 2* degree overall overlap and increases the DCR by .3, over the -1. VE stays 2-3% higher after 4000rpm. It should peak and carry much better than the -1.

ty_ty13

iTrader: (42)

tell me about this cam that i have in a blown 408 with stock heads... where should it peak?

224/236 .601/.602 114lsa

i'll tell you where it peaks after you guess im actually having problems thats why i asked cam questions...

ALLBOTTLE

iTrader: (13)

it's a bit different with a blower than a na application.

What size blower? Heads? pulley ratio? compression?

On a NA 408 with stock ls6/6.0 heads i would expect this cam to make Peak Hp @ 5800 peak tq @ 4800

ty_ty13

iTrader: (42)

holy ****... my blown motor is peaking at 5830 rpms... so what does that mean?

ALLBOTTLE

iTrader: (13)

That i'm really really good at physics and calculus

It doesn't mean anything just that you have a very linear power band. Are you looking for more peak or more under the curve?

You have to remember that Hp is 100% dependant on TQ, the key to making more Hp is to get a cam or degree it so that it will carry the TQ band longer.

ty_ty13

iTrader: (42)

im wanting to carry the HP further in the rpm range.... if it made the same power at a higher rpm and kept carrying the power until i let up i would be fine with it.... right now i have a 12bolt and 3.73's is as low numerically as i can go and still have a spool... sooner or later the car will be trapping in the 14xmph in the 1/4 and hopefully 11x in the 1/8th... and 5800rpms is not near enough power band...

ty_ty13

iTrader: (42)

another thing is i have a 7.65 crank pulley and a 3.4 BP and at 5800rpms thats 53500 impeller rpms on the d1sc... which is another 850 below max impeller rpms...

with my pulley setup 6700rpms is push the blower about max impeller rpm... i realize that pushing it to max impeller rpm is not neccessarily the best thing... since 62000rpms is the max on the d1sc i'd like to push it to around 58000rpms

this would make me shift at about 6400 rpms...

PREDATOR-Z

Now if the cam is more intake biased from TDC, IVO 1* or 2* sooner than EVC froim TDC, doesn't that mean that the cam will carry the power longer after peak? (in general)

Advancing the cam makes it more exhaust biased, more peaky if you want, I'm trying to understand what you mean by "carry" much better.
Is it like carry the power longer after Hp peak, or carry more power after trq peak?

ALLBOTTLE

iTrader: (13)

In general a cam with a more ground-in advance will carry longer after peak but it will not peak as high.

In this perticular case the 230/228 .592/.588 111+4 will carry the power longer after peak HP and make more average Tq.

PREDATOR-Z

Alex,

These are the VEs of both cams:

230/228
111 LSA/ 112 ICL (-1)

IVO>3
IVC>47
EVO>44
EVC>4
ECL>110
7* overlap

230/228
111 LSA/ 107 ICL (+4)

IVO>8
IVC>42
EVO>49
EVC>-1 (BTDC)
ECL>115
7* overlap

That doesn't jive with what you're telling me.
Clearly the +4 is very exhaust biased, making the power band lower in the range, IVC of 42 will also make it peak earlier Vs 47 IVC.
If the cam peaks later, it is also natural that it will carry further into the rpms.
The trq on the 44 EVO will also be more pronounced in midrange and will come earlier on. 49 EVO will also make that trq stretch longer instead of falling off rapidly after peak.

ALLBOTTLE

iTrader: (13)

I see what you are saying, When i say VE i don't mean Valve Event, I'm talking Volumetric Efficiency of the motor.

In this case the for what ever reason whether it be the cam's ability to eliminate residual exhaust in the combustion chamber or just sheer luck, the physics behind the +4 will make more power and carry it further with almost identical power under the graph.

PREDATOR-Z

Yeah, but VE depends on the total combo (head flow, head design, valve angle, plug position, quench, DCR, exhaust setup etc...)
In this case the Valve Events dictate the maneurism of the cam.
Combo properly matched, the -1 cam will go higher in the rpms with a flatter longer lasting Hp average after peak.
That is what It is designed to do, no luck

ALLBOTTLE

iTrader: (13)

I am Aware of How VE is calculated.....

We just have Different Points of View On Cam Theory;
On this cam We will just have to agree to disagree.