Printable View
I don't see much talk about cams here..
However, I'm somewhat new to the board (thanks jim)
I know the guy at Comp Cams that heads up the Zex dept. and they are planning on designing a cam around supercharged B series honda engines.(as well as cams for other Honda applications) Whats the low-down on cams with forced induction???? : )
just curious what any of you might have had luck with.
Daurie
------------------
Cams for Supercharged cars!?!?!? yummmmmm....... http://www.hostboard.com/ubb/biggrin.gif
------------------
95 EX Coupe w/SC'd JDM B16 @9 psi
http://community.webshots.com/user/hybridex
From what I hear the cam is mild. Makes more lift but no more duration to speak of. I haven't got any details yet. If I hear anything else I'll post..
Daurie
------------------
right now the stock gsr and civic si cams are choice for fi . some people have had minimal success with other cams , but only after an exhausting and expensive amount of tuning . hopefully some future grinds will provide reliable gains . the stock cams might just be the best , not everything can be improved .
------------------
99' GSR / JRSC @ 6psi
-JR MAP & BTC
-Walbro 342
-Comptech exhaust & intake/icebox
-Comptech/Koni coilovers
-Mugen 22mm rear sway bar
We can use the extra lift... however, this comes with a price: DURATION. The overlap that is created to safely make the transition from the base circle to the peak of the lobe causes compressed air to escape into the exhaust... and this not only disrupts the exhaust waves and chokes the motor, it also allows alot of heat inside the combustion chamber thus reducing it's combustion efficiency.
As stated above: There is nothing currently available that is BETTER than the stock cams.
Hopefully, this will change soon.
BTW, call me in the next few days... I need to talk to you.
------------------
'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph
There are a few cams out there for our applications. Crane cams have designed 3 supercharger cams for the B18A/B engines. They call them "high compression cams" but after talking one of the Crane brothers he said the 0016,0018 and 0020 cams were designed using a JRSC B18A1 in a CRX. The 16 is a street cam, the other two are race only applications that barely idle and really unusable under 3000 and 4000 rpm respectably. Here is the site. http://www.cranecams.com/import/acuracamsn.htm
I just bought the 0016 cam with the spring kit. The engine is being put in my car soon. so I will let you all know how they did.
I have researched for a SC cam for a year now. This is what I have found out:
For a SC cam, You want as much lift as possible without adding duration. This will keep your stock-like power curve right where you have it now. It creates a less restrictive entry into your combustion chamber think of it like opening a door wider. But only a few HP can be found with this set up.
There is no magic cam to make more power in your existing rev range. You can spend hundreds of dollars to find 1-3HP, but it all comes down to your useable torque range. Which is only about 3300rpm wide. (Superchargers add 500rpm on both sides making it 4300rpm wide). All duration does is shift this power band up and down the RPM range. What VTEC does, is use two cams to make this torque range another 1000rpm wider.
Example: If you were to use a large duration cam on a stock LS, equivalent to the VTEC big cam on the GSR, you would shift your usable torque range 3000-6300rpm up to 4200-7500 range. Go figure Honda has the VTEC engage at 4400 rpm. Hmmmmmmmmmmmmm? So the bad torque range common with the LS from 1000-2000rpm will now be now at 2200-3200. Which is a 15-25ft.lb drop in torque! But you will now have HP equal to a GSR. That is if all things were equal inbetween the two engines, intake manifold, comp ratio, stroke etc... These are all minor in the big picture, because of subtle diffences. This otherwise stock LS would make around 5HP less than a stock GSR.
WHY you ask?
Torque equals HP at 5252rpm. So at 2626RPM 1ft lbs=1/2HP and at 7878RPM 1ft lbs=1.5HP. Don't believe me, look at any dyno graph ever made. Once you start studying torque curves you will learn alot more. If you were to take the LS pk torque (110ft lbs)which happens to be at 5200rpm, it would equal 110 HP at 5200 rpm. So, If you put in long duration cams that shift this 110 torque peak 50% higher in the RPM band to 7878rpm, you will now have 50% more HP (165HP at the wheels). Your usable torque range would be 5500-88000, you would have to set your idle to 2000rpm to keep it running, and would make operation below 4000rpm unbearable and unusable due to a 50% drop in torque.
The cams I bought will shift my power band only 1000rpm. Which means I need to stay above 3000rpm around town and race my engine another 1000rpm at the track to make use of the extra HP.
So cam it and rev it!
------------------