Thread: Larger Cam With Larger Rocker Ratio's?

About to order my Yella Terra's. Spent the last while working on finishing up some unfinished work the machineshop left for me to do...

Anyways the heads, valves and everything is setup for a .6 lift to run the XPZ and a bit more. Pedistal cut and everything. Any reason I should consider running a 1.7 Yella Terra over a 1.6? I have heard of guys with the smaller cams like the VS cam doing it but, recent;y heard of another member running a higher lift rocker with a custom cam grind similar to the XPZ I'm using.

Thoughts?

I'm sure that I've seen where people have run 1.7's on the IS3 cam, now is it worth the money vs the gains? I doubt it, but then again, if you're going for every little bit of power you can get.....it might be worth it to you.

I stayed 1.6 on mine just to not to have to worry about it.

Originally Posted by Bio248

brian, have you changed cams yet? from what ive read and understand, an XP with 1.7s will rival (if not beat) and XPZ setup because of how the cams themselves are designed.

i have an xp cam with stock rockers, what would i have to do to run 1.7s?

Originally Posted by Bio248

brian, have you changed cams yet? from what ive read and understand, an XP with 1.7s will rival (if not beat) and XPZ setup because of how the cams themselves are designed.

I haven't...Got a new motor ready to put in, but time and weather got ahead of me. 5 degrees outside isn't really a big motivator for me to have the garage door open to pull the engine out. I'll have to wait for the weather to clear up before I'm gonna get the motivation to do that.

Originally Posted by Bio248

buy them and put them on. also youd need to make sure your heads would have enough clearance for the extra lift.

thats what i meant. cuz i heard that u cant run 1.7s with an xp because of the clearance. i dont know how to check that. valve clearance? is that what i have to check?

Originally Posted by Bio248

machine the valve guides to be .100" shorter and youll be able to run high lift stuff, but having no porting wont help you when you would like to run a big cam.

the whole top end of my motor is ported.

Originally Posted by Bio248

top end is including heads? ported how? by whom?

yes. the heads arent really ported all that they could be. since i did them myslef. i basically just took off all the rough edges inside the ports and smoothed it all out. i think im gonna go back into them tho and port it out more. i bought this porting kit at an auto parts store near my house.(not an autozone). more of a high performance store. van senus. its local. it came with a whole bunch of different bits. i used a die grinder(spellcheck). i ported he outer edge of my throttle body, like where that lip is. ported out the sc around the inlet a lil and made the outlet bigger(triangle shaped opening). i also have ported manifolds, but i dont think they do much. they were free basically so whatever. it was my first time porting so i didnt want to do much. my cousin did his heads on his LS1 so he helped me too.

Originally Posted by JJ91284

Porting the inlet is fine on the supercharger as long as you tried to smooth out the rough casting. Touching the supercharger outlet triangle is bad and you probably hurt the efficiency of it some. The only thing you really want to do is take the sharp edge away from the outlet "V" on the inside and outside so its a smoother transition and port closer to the snout end of the supercharger as this is where the most volume of air comes out of the charger.

hmmm. can you get a picture of a ported m90 and a stock m90 to show the difference?

Originally Posted by JJ91284

This is a good outlet pic from our vendors

https://www.zzperformance.com/products_img/162_1.jpg

alright. well i have my whole engine apart so im gonna start doin some more porting.