I need help about camshafts

[1blkstang]

This is not a "pick a cam for me" thread...I need some more help on the relatsionship between duration and spreading
out the lobe centers...To get the best idle....And to get the best duration at .020.... .050 for peak performance

I found this on wikipedia "increasing a camshaft's duration typically increases the overlap event, unless one spreads lobe centers
between intake and exhaust valve lobe profiles.".....How much is to much duration before it will dramaticly effect overlap..

Im trying to read up on the functions of cams so in the end I can build myself a cam to my style of driving and a STOCK idle on the street

Thanks for the help!

 

[MadStang]

I need help about camshafts

Valve overlap determines how much lope a cam / set of cams has. Stock cams are into negative overlap on modulars.

You take the intake/exhaust duration at .050 and add them together. Divide by 4. Subtract by LSA. then multiply by 2. That's how many degrees of overlap you will have.

 

[1blkstang]

Okay i'll do some math then and check it out...Thanks

 

[1blkstang]

"You take the intake/exhaust duration at .050 and add them together. Divide by 4. Subtract by LSA. then multiply by 2"

Im having a little trouble here...Trying to get the math down with the stock camshaft as an example..
Found this info on the stock cams

91-95:
Lift: .278 intake, .278 exhaust
Duration: 276 intake, 266 exhaust
Overlap: 39 degrees, 19.51 factor
Lobe Center: 116 intake, 115 exhaust

Overlap is 39...and im adding duration at say 210 or 204 on both I/E side and doing the following with a LSA of 115?

I get a negative of 26?

Am I missing something here? Thanks for the help!

 

[MadStang]

I need help about camshafts

"You take the intake/exhaust duration at .050 and add them together. Divide by 4. Subtract by LSA. then multiply by 2"

Im having a little trouble here...Trying to get the math down with the stock camshaft as an example..
Found this info on the stock cams

91-95:
Lift: .278 intake, .278 exhaust
Duration: 276 intake, 266 exhaust
Overlap: 39 degrees, 19.51 factor
Lobe Center: 116 intake, 115 exhaust

Overlap is 39...and im adding duration at say 210 or 204 on both I/E side and doing the following with a LSA of 115?

I get a negative of 26?

Am I missing something here? Thanks for the help!

Is that duration at .050" or advertised duration (.006") That doesn't seem right for OEM and I believe you're getting advertised duration specs when you need .050".

From what I read 95 5.0's are spec'd at 210/210 115LSA

210+210= 420

420 divided by 4 = 105

105-115 = -10

-10 x 2 = -20

Stock 95's have -20 degrees of overlap.. Which means that the cam lobes are separated 20 degrees reverse of what is determined as 0 valve overlap. I'm not sure of the specifics of it but the further into the negative, the less the valves overlap each other making the idle smooth versus choppy.

 

[1blkstang]

Yeah you mentioned that on your 1st post about the negative overlap and the other night i was finding out the overlaps on my the two cams that I have E cam both at 220.. .050..110 lsa and xe276 224 intake 230 exhaust .050 112 lsa...and I believe they both were in the 50s... Yeah with the stock cam its a little hard bcuz ford changed them so many times that theres some saying 204 at .050 or 210...Eh but anyways im having fun messin with these numbers to either call for a custom cam or find the right one...

 

[MadStang]

best way to make the most power is get a custom cam grind IMO. it may be a bit more but it's definitely worth it. I have off the shelf cams in my roush currently and I'll never do it again because it isn't EXACTLY what I wanted.

 

[1blkstang]

Yeah I agree man..To build something right is going to take time ( money and prep )....But yeah last night I think i was to tried cuz rn im getting different ovrlap answeres to both those cams bcuz 50 ovrlap seems to high now haha....Got yourself a roush huh? how do you like that thing?

 

[MadStang]

Yeah I agree man..To build something right is going to take time ( money and prep )....But yeah last night I think i was to tried cuz rn im getting different ovrlap answeres to both those cams bcuz 50 ovrlap seems to high now haha....Got yourself a roush huh? how do you like that thing?

haha I hear ya dude. the cams I'm going for have 28.5 degrees of overlap. that's huge for a modular. This is similar to what they will sound like but mine will be slightly more aggressive...

http://www.youtube.com/watch?v=9Yr7_VA0X30

well if it ran I'd like it more hahah. i'm tearing it apart again for a new motor. but I do absolutely love the car, Roush was meticulous with the suspension and I've never driven a car that felt this planted before honestly.

 

[1blkstang]

You say yours will be more agressive? That car sounds anrgy but music to the ears Lol..I love how those mod motors rumble
Yeah a buddy of mine got a 427r last year..Took me for a spin and WOW! My 302 cant be compared....Yeah Roush makes just great cars..Honestly thats kind of what im shooting for..a roush stang build...

Are the sn95 roushes superchargerd?

 

[MadStang]

You say yours will be more agressive? That car sounds anrgy but music to the ears Lol..I love how those mod motors rumble
Yeah a buddy of mine got a 427r last year..Took me for a spin and WOW! My 302 cant be compared....Yeah Roush makes just great cars..Honestly thats kind of what im shooting for..a roush stang build...

Are the sn95 roushes superchargerd?

yup, popping off like a popcorn maker hahah. Nice man, as far as the SN95's they did not come with a blower, 95 Stage 3's made about 330rwhp n/a with upgraded heads and such but that's about it. Still the suspension is second to none IMO.

 

[1blkstang]

We went snowboarding a week ago and he told me on the drive up that he isnt really happy with his car and I was about to slap him..Hes kinda scared I think of the car..haha shit let me drive it you know...Those cars really have no limits which is awesome..
Like you say suspension and thats what Im about..A great handling to power ratio car to me is the best sports car you can have.. So your 99 is n/a?

 

[MadStang]

haha yeah, I drove my brothers 427R, they're definitely a blast but only when traction control is off haha.

Yup my 99 is N/A, I'm in works with MMR and MHS currently for my car. I'm going with similar guidelines for whats called the "2v Recession Buster" Build (type it in google, there's a nice thread on the Corral about the build). I'm planning on getting this car onto the Road course by 2012 for NASA's TT series.

 

[1blkstang]

Dude I like that dyno graph! Great TQ threw the whole rpm.. Kind of jealous Lol..I want similar numbers as that.. Nasa bound huh..sounds fun..Im in the same field as you man..And I got laguna seca 30mins away from me...F**K do I wish I can throw money at this car right now!

 

[MadStang]

Dude I like that dyno graph! Great TQ threw the whole rpm.. Kind of jealous Lol..I want similar numbers as that.. Nasa bound huh..sounds fun..Im in the same field as you man..And I got laguna seca 30mins away from me...F**K do I wish I can throw money at this car right now!

I hate you. LOL I wish the Seca was that close. After I get a feel for the car at local tracks (mainly autoclub's ROVAL; my home track ) I'll be trailering the car up there, I've driven the Nurburgring in a POS Alfa Romeo Rental Racecar now I gotta hit up the track I've been dreaming about since a kid!

 

[1blkstang]

The 99 will only be a track car? HA yeah and not to rub it in bcuz it kills me too..I work 10mins from the track and when they run it I can hear all the cars out there and duude! makes me want to run out there..

 

[MadStang]

The 99 will only be a track car? HA yeah and not to rub it in bcuz it kills me too..I work 10mins from the track and when they run it I can hear all the cars out there and duude! makes me want to run out there..

nah not just a track day, it'll do some weekend driving but it's gonna be the furthest thing from a DD with those cams lol

 

[1blkstang]

Yeah since you live in cali too..whats your SMOG situation?..The whole thing that is holding me back is this damn smog! ( cant do this or that ) Yeah same here weekend car fun and some track days

 

[MadStang]

I need help about camshafts

Yeah since you live in cali too..whats your SMOG situation?..The whole thing that is holding me back is this damn smog! ( cant do this or that ) Yeah same here weekend car fun and some track days

I have people... Lol

 

[1blkstang]

Ahhh damn you Lol...Places around here are a hit and miss. Some dont want to deal with it...UNless you take it to the eastside and those guys dont care..They'll just use a different car Lol