Cams...

[matwood]

Ok, so I'm at the stage of my build to choose a cam and jets for my Mikuni 40's.

 

I've got my eyes on a Nissan Motorsports L9 cam for my L20B. (290 Duration and .490" lift.)

 

The block is bored to 86mm and fresh back from the machine shop.

 

The A87 peanut and intake manifold will have a pretty hefty port job on them and I'm looking to build a daily driver that will have some BALLS.

 

Is the cam I mentioned gonna be enough? I don't mind running premium gas at all.

 

Also, what jets would you all recommend for the Mikuni's...?

 

Oh, and will this cam warrant stiffer springs and such, or just refurbished ones?

 

 

Thanks guys...

 

-Madison

[datzenmike]

The longer the duration the cam, the less drivable it is at lower RPMs. Power and torque tend to clump in the above 5K zone and intake vacuum drops so low the carbs barely work at idle. 290 is at the upper end for a DD. If you want easy cold weather starts and good idle with comefortable stop and go driving around town 290 is on the edge. Try it, performance won't dissapoint but living with it might. The good thing is a cam change isn't that hard to do if you decide to change it.

 

As for premium gas, it's use is solely on the need to reduce pre ignition detonation. This is usually a function of compression ratio.

[banzai510(hainz)]

webcamshafts.com make a 488 252 duration I think that would be a better street cam myself.

 

I would set cam on #2 sprocket hole

 

Just mY opinion. I have 2 of these cams but havent run them yet.

 

4.11 Gear ration would wake a motor up

 

I have a 475/275 cam and it takes awhile to pull power out of my L16 but I do have a 3.70 subi diff. whaich might be why it take awhile to pull. and set on #1 sprocket. I do have 40mm Mikunis also

[RoadRace]

the cam chioce is also relative to the size of the engine. 290 in an L20 is easier to live with than in an L16. Auto trans vs Std is a consideration.

[imtb]

I have an ISKY stage II I am running right now and it is very decent cam, Idles good, good peformance.

 

I think isky cam a good profile nice pointy lobes.

 

I wouldnt mind trying the stage III, but it would be all uppper end above 6000rpms. I like some low torque.

 

My HO is ISKY cams are the best going, You are going to get what you order and Package and cam info. and Ron will help you decide if you want his help.

[hang_510]

I do have 40mm Mikunis also

do you have your list of installed jets ?

i lost my notes in the move :angry: :angry: :angry:

[banzai510(hainz)]

these carbs I just bolted on and it works fine. Smooth idle. cant tell it has a cam 475/275 if its correct but never measured it. It was Delta regrind. Other Delta Cams I bought were not as spec

 

My jets are 135 main, 160 air (40mm)

 

I think (44mm base) is 160main, 240 air