Zach79Z

iTrader: (21)

Been doing some research on cams and found a post that states for a choppier idle to have a lower ICL (i.e 112 +2) I have been looking at Vengeance Racings VRX4 Camshaft but heard it isnt very choppy so i was curious if it would change the cams performance to grind a advance such as 112 +2 into the cam or if it would just make the cam choppier and change its street manners?

Here are the specs-
228/230 .588/.592 112 LSA

Here is what i am thinking-
228/230 .588/.592 112 +2 LSA

I dont believe there is any advance ground into the cam off the shelf but i have not got a chance to ask Vengeance about it yet.

Any help is appreciated

Thanks

Zach

'91firebirdformula

iTrader: (3)

I'm no cam guru by any means, but adding 2 degrees of advance will change the characteristics of the cam. The lower lsa will give it more chop, yes. but not by going from 114 to 112. not 112 to 112+2. someone else will give you more help though.

Zach79Z

iTrader: (21)

Well the reason i thought 112+2 would make it chop more is cause i thought (correct me if im wrong) the +2 ment the lsa was a 110 and since i thought the lower the icl the choppier itd be more choppier with the +2 in it. I had some thoughts about it changeing drivabilty but figured id ask anyways

rmtt

iTrader: (8)

Idle quality comes more from "overlap" than LSA. I posted a formula sometime back that shows how you arrive at overlap using duration and LSA that I found from a search on here.

The cam in my sig has only 9 degrees of overlap, but even on a 110 LSA, it sounds more tame than others on a 112 or 114 LSA that have 10 + degrees overlap.

Zach79Z

iTrader: (21)

ill have to look up that formula thanks

hammertime

iTrader: (1)

Apologies if this was covered in an earlier reply, I did not see it when I read through them.

In your example, 228/230 .588/.592 112+2, the Lobe Separation angle is 112 degrees. The "+2" signifies that the cam is advanced, either ground or installed, at a 110 degree Intake Centerline. This does not change the overlap between Exhaust and Intake. You can change the duration of either or both lobes, or change the LSA. Essentially, only changing the cam will change overlap.

Overlap = [(Intake Dur. + Exhaust Dur.)/2] - (2* LSA)

Since both the cams use the same durations and LSA, they will have the same overlap.
[(228+230)/2] - (2*112)
229 - 224 = 5 degrees overlap

Tighten it up to a 110 LSA, and you get more overlap
[(228+230)/2] - (2*110)
229 - 220 = 9 degrees overlap

Zach79Z

iTrader: (21)

VERY GOOD INFO! It was covered but the formula shown helps. Plus saved me time from looking it up lol. So basically i should get the cam ground on a 110 (for instance) with the specs of this cam if i wanted a choppier idle due to more overlap. What all will i have to check with the lower lsa? I.e. PTV etc. I know im suppose to check it anyways just curious if there is something more i should check or if something else changes with the lower lsa. I really appreciate everybodys help.

Zach79Z

iTrader: (21)

ALSO with the 110 LSA should i leave out and advance or retard ground in the cam?

Shawn MacAnanny

iTrader: (12)

I have a 110+4 and it barely clears. The 110lsa is going to bring your powerband down and the advance will bring it down a little further.

Zach79Z

iTrader: (21)

So im going to see more torque and a little less horsepower with a lower LSA

Shawn MacAnanny

iTrader: (12)

From everything i know lower LSA bring your power band down lower, raises dynamic compression slightly and SHORTENS the overall effective power band. IE say a 114 makes power from 3500-7500 a 110 on the same duration will make power from 2800-6500 or something like that.

Zach79Z

iTrader: (21)

Oh i see. Accorindg to Vengeances website the cam power ranges from 1900-6700 Would it be a bad idea tod rop the cam to a 110 since itd drop the power band into 5xxx?

Shawn MacAnanny

iTrader: (12)

nah maybe like 6400. Honestly i have nothing to base this on. I'm drinking, but just going of what ive learned during my cam search. With my 110+4 my cam pulls like a freight train thru 6800rpm, still havent taken to 7000rpm but im waiting until i got the AF perfect since my intake valve is something like .030" from my piston or so.

Zach79Z

iTrader: (21)

LOL always the best time to help people lol nah im just kidding. Based from the info you gave me i can look at a lower power band up top but would it also lower it down low? I.e generate torque and hp at an earlier rpm?

Shawn MacAnanny

iTrader: (12)

Yes, lowering the LSA brings power on sooner, makes max power sooner and at a slightly lower relative rpm. From what understand. I've only had a pint of vodka, probably 1700 of my posts were under atleast those circumstances hopefully someone will chime in and reassure you . I did do alot of research before building my car though.

Zach79Z

iTrader: (21)

hmm...Sounds like something id like. I really want a torque car and want it at a fairly lower rpm (2500 or so) and i dont really wana turn the car up to 7000 rpms. But i dont know if itll be good if it maxes out at 6400 (so to say)

Lol they say you think better while under a buzz lol

Shawn MacAnanny

iTrader: (12)

I remember more under a buzz. It'll make power that far. You may want to go with a slightly larger cam. Most people running a 228 are using a 112 or 114lsa if you notive. Go 230 or 232 and a 110 and you will be happy with the rpm range. I am running a victor JR so my engine wont make power until about 3500rpm anyway so i cant really compary my cam to any you select

Zach79Z

iTrader: (21)

Yeah im guna have a fast 92 on mine. Patrick G is specing me a cam this is just another cam i had in mind. Hinda sucks vengeance doesnt have a lower 23x 23x cam

Shawn MacAnanny

iTrader: (12)

Yeah there's your best cam right there. I kind of specd my own looking for them in the for sale section when i was looking for mine. I wanted the same duration. high lift and a tight lsa advanced since i was running a carb setup but that was like 2 years ago, I'd have my EFI cam specd by pat g any day.

Zach79Z

iTrader: (21)

Yeah from what i filled out hopefully itll be a mild cam that sounds nasty lol