actually,they have a dyno on their website. 26whp gain from stock.... i got them in my car and gained 24whp, only 2hp off.

dyno sheet

Josh F wrote:

Skilz10179 wrote:

Josh F wrote: (i know you dont want much over lap because of the boost)

Misinformed.

and how am i miss informed? tell me why a big over lap is good with boost? your forcing the air into the cyl any way .. so all your going to be doing with a big over lap is forcing it in and its going to be pushed out as well... there for making it pointless you wont loose any thing from it but no much of a point to it

I must have missed this post, sorry.

Bigger over lap not good with boost or not good with turbocharged motors??? There is a big difference. Turbocharged motors might not like the lengthened duration but a supercharged motor might.

Cams for a turbocharged motor will work better with a shorter duration simply for the fact they have an extremely restrictive exhaust system. When you have extreme backpressure in the exhaust manifold like turbocharged motors have it makes it harder for the motor to inhale air when the intake valves open during the over lap before the exhaust valves have closed due to the backpressure. The main reason it isn't usually suggested to use hotter cams on a turbo motor is due to the fact that with longer duration comes more valve overlap. With more valve overlap come less exhaust energy at lower rpms where the cam is not designed to make power. With less exhaust energy at lower rpm's comes more turbo lag, and so on...

As for these negative side effects on turbocharged motor, in my understanding and expericance. They only apply at low rpms and show nothing but positive effects at high rpms just like they would in a n/a application.

Since a supercharger is not dependent on exhaust energy to make boost, it will not see the same negative side effects from hotter cams as a turbocharged motor might.

As for the original question, my cams have .410" lift and 212 degrees of duration. 212 degrees is a decent amount of duration over stock but is not really considered to be a very hot cam and is not too much for a turbocharged engine.



- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

Quote:

Race Tech Custom Grind Cams. (Specs given to me)

-Orig these puppies went for 700 to 850 $ new.
-Intake Cam: Duration @ .050 - Int. 216 - Lobe Lift .380
-Exhaust Cam: Duration @ .050 - Exh. 206 - Lobe Lift .365

Thanks for the information. I have a new set of HO cams, but I wanted to find the best cam for my SC application. Hopefulley I can use the specs to match the cam to my cylinder head.




Jason
99 Z24
157hp/171tq
wheres my boost??

Skilz10179 - ahh i see ... we were just on 2 different paths there for a bit... i get what you were trying to say... but im also asking about for my set up since yes i have the supercharger but also have the turbo back there too remember... so a bigger over lap for me would not be the best ... i think im just going to let JBP decide the specs as i am having them build the engine for me, since they know the oiling problem of the LD9 where as a local engine builder might not...



The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno

Josh F wrote:Skilz10179 - ahh i see ... we were just on 2 different paths there for a bit... i get what you were trying to say... but im also asking about for my set up since yes i have the supercharger but also have the turbo back there too remember... so a bigger over lap for me would not be the best ... i think im just going to let JBP decide the specs as i am having them build the engine for me, since they know the oiling problem of the LD9 where as a local engine builder might not...

Maybe i wasn't very clear. The longer duration will hurt lower end power by adding turbo lag but add tons of power on the top end of the power band. Since you don't have to worry about turbo lag as much because of the supercharger it shouldn't effect your low end power any more than it would on a n/a motor.

Compare any aftermarket cams vs stock cams for factory turbo motors, they all have longer duration and they are all a lot hotter than any cams out there for our motors unless they're a custom grind.


- 93 mph in the 1/8 mile
Member of J-Body Of Michigan.

My current cam setup.... w/ stock cam timing

Intake: 200* @ .050" with .375" lift
Exhaust: 212* @ .050" with .410" lift


Possible future cam setup..... w/ 2* intake advance / 2* exhaust retard cam timing

Intake: 212* @ .050" with .410" lift
Exhaust: 212* @ .050" with .410" lift

I also have a set of PowerTek cams that need to be spec'd out...... w/ +/- 4* gears


For Reference

*** Comp Cams Street/Strip N/A EcoTec Cams ***
Intake: 216* @ .050" with .440" lift
Exhaust: 218* @ .050" with .436" lift

(more over lap)

*** Comp Cams SuperCharge EcoTec Cams ***
Intake: 210* @ .050" with .423" lift
Exhaust: 218* @ .050" with .436" lift

(less over lap)

*** Comp Cams Turbo EcoTec Cams ***
Intake: 204* @ .050" with .423" lift
Exhaust: 200* @ .050" with .419" lift

(least amount of over lap)



Edited 1 time(s). Last edited Tuesday, November 28, 2006 1:46 AM

SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
W41 BOI - '78 Buick Opel Isuzu W41 Swap

WOW...with some of this information in mind...and assuming the LD9 and eco react the same way to differenct cams...which is kinda bull@!#$ but for the sake of saying I'll make that assumption. It would say that although the HO cams are a bit aggressive on the overlap for boost, but the lift is about appropriate for the goal. Maybe some degree cams to advance the intake and retard the exhaust to reduce some overlap and you'd be pretty close to ideal. Or so the assumptions made would say so.