Drop some Cam Knowledge on me
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Drop some Cam Knowledge on me
So, I cant keep my wife from vacationing away our spare income so I haven't had anything to really do on my car since I finished my H/C/I set up. That being said, I thought I would spend some of my spare time learning more about cams and have started working my way through the stickys on the subject.
When I started this car I consulted Martin Smallwood about my goals, etc. and he recommended the Tick SNS Stage 3 cam and TFS as cast 220 heads. After hearing some other options in my budget and speaking to Martin some more, that is what I went with. I am tremendously happy with those choices and really enjoy the car when I choose to drive it. I paired all that up with the basics.... 92/92 set up, AR long tubes, Magnaflow cat back, appropriate fueling, and a S60 w/ 4.10 gears, etc...
I got it all put together and brought it to Pat G in Victoria for tuning. Again...really happy with the outcome.
Where I get a little lost is that I read a lot of posts where people are recommending folks run a "smaller" cam for low end torque and I get a little lost with that recommendation as I feel like my car has plenty of low end grunt. My cam experience is limited to this cam (235/243 .630/.610 111+2), a 224/224 in a different car, and a blower cam from Thunder Racing on a PC car wayyyyyy back in the day that I cant remember the specs on. I have even had folks comment that they thought the SNS Stage 3 was a little large. Just looking to learn, not change my set up. Like I said, I really like it. Is there a cam that you think would preform better as just a Sunday driver/street car/ rare trips to the track? I feel like the one in there is a pretty good balance between some low end torque and pulling pretty hard up to 6800. The car screams under WOT. I attached my Dyno sheet from the tuning with Pat in Victoria to reference (Mustang Dyno). I thought it may be relevant and may help you educate me. Drop some science on me if you have a few spare minutes...
Thanks Fellas
When I started this car I consulted Martin Smallwood about my goals, etc. and he recommended the Tick SNS Stage 3 cam and TFS as cast 220 heads. After hearing some other options in my budget and speaking to Martin some more, that is what I went with. I am tremendously happy with those choices and really enjoy the car when I choose to drive it. I paired all that up with the basics.... 92/92 set up, AR long tubes, Magnaflow cat back, appropriate fueling, and a S60 w/ 4.10 gears, etc...
I got it all put together and brought it to Pat G in Victoria for tuning. Again...really happy with the outcome.
Where I get a little lost is that I read a lot of posts where people are recommending folks run a "smaller" cam for low end torque and I get a little lost with that recommendation as I feel like my car has plenty of low end grunt. My cam experience is limited to this cam (235/243 .630/.610 111+2), a 224/224 in a different car, and a blower cam from Thunder Racing on a PC car wayyyyyy back in the day that I cant remember the specs on. I have even had folks comment that they thought the SNS Stage 3 was a little large. Just looking to learn, not change my set up. Like I said, I really like it. Is there a cam that you think would preform better as just a Sunday driver/street car/ rare trips to the track? I feel like the one in there is a pretty good balance between some low end torque and pulling pretty hard up to 6800. The car screams under WOT. I attached my Dyno sheet from the tuning with Pat in Victoria to reference (Mustang Dyno). I thought it may be relevant and may help you educate me. Drop some science on me if you have a few spare minutes...
Thanks Fellas
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Being that you have 4.10 gears and a manual I think that cam is a fantastic fit with those heads. The 4.10's help to compensate for the big cam down low and then you have awesome mid range and top end. Your setup is really good IMO.
I have 4.10's and a 6-speed with a cam very similar to the SNS 3 but with PRC 5 3 heads. I love it
I have 4.10's and a 6-speed with a cam very similar to the SNS 3 but with PRC 5 3 heads. I love it
#3
Thats with my 222/228 on a 113+4 .567 .567
Longtubes, magnaflow catback, ls6 intake and stock 799 heads with a 278mm CircleD budget converter. Clearly you have more top end while my mid range is much better. (In regards to the power curve itself, not the actual numbers produced) You make more horsepower.
With similar heads my torque output would outperform yours. Although I would still make less horsepower.
Your combo is much peakier. Mine is flat. So one would assume mine would be fun for a circuit track or canyon runs. Yours will be fun in a straight line.
Last edited by Bspeck82; 06-14-2017 at 09:26 PM.
#4
To be basic. Its not that one cam is better then another. They all have a specific purpose. The valve events, which are what dictate the duration we see when browsing cam catalogues, will give you an idea of when the engine will make power, stop making power and how much valve overlap it will produce. Keeping the intake valve open longer (biggerintake duration number) will make more top end power because more time is allowed for the cylinder to be filled with air moving at what we hope is a high velocity. Provided your lift specs for heads and cam are matched right. You loose bottom end power because of poor cylinder filling and what is known as EGR. The exhaust gasses go right back into the intake, causing poor air fuel mixture quality for a terrible burn and everything is also much hotter. More overlap is not suitable for low rpm because of the same directly related reasons. But this effect is good at high rpm because volumetric efficieny at high rpm is better because exhaust gasses pull intake mixture into the cylinder faster allowing for a cleaner better burn. And the intake centerline also change up where engines make power. Typically you will see cams with 112-114 LSA grounded with a 3 or 4 degree advance for an intake bias for more low end power. So my cam has an LSA of 113 with a 109icl and a 117ecl. LSA is determined by adding the centerline and dividing by 2. Advancing a cam opens the intake valve sooner, hence why it builds more bottom end torque and chips away at the top. Retarding it does the opposite. Something else to understand is lobe intensity. Ideally you want a valve to open and close instantly. We cant do this yet but the faster you can do it, the better for power. Although its also harder on the valvetrain so there is a balance of power to be had but its ultimately your choice. Thats just a few basic things to know. There are many good reads of you google it. Isky cams has some insight as well on their site about their research.
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Being that you have 4.10 gears and a manual I think that cam is a fantastic fit with those heads. The 4.10's help to compensate for the big cam down low and then you have awesome mid range and top end. Your setup is really good IMO.
I have 4.10's and a 6-speed with a cam very similar to the SNS 3 but with PRC 5 3 heads. I love it
I have 4.10's and a 6-speed with a cam very similar to the SNS 3 but with PRC 5 3 heads. I love it
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Thats with my 222/228 on a 113+4 .567 .567
Longtubes, magnaflow catback, ls6 intake and stock 799 heads with a 278mm CircleD budget converter. Clearly you have more top end while my mid range is much better. (In regards to the power curve itself, not the actual numbers produced) You make more horsepower.
With similar heads my torque output would outperform yours. Although I would still make less horsepower.
Your combo is much peakier. Mine is flat. So one would assume mine would be fun for a circuit track or canyon runs. Yours will be fun in a straight line.
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To be basic. Its not that one cam is better then another. They all have a specific purpose. The valve events, which are what dictate the duration we see when browsing cam catalogues, will give you an idea of when the engine will make power, stop making power and how much valve overlap it will produce. Keeping the intake valve open longer (biggerintake duration number) will make more top end power because more time is allowed for the cylinder to be filled with air moving at what we hope is a high velocity. Provided your lift specs for heads and cam are matched right. You loose bottom end power because of poor cylinder filling and what is known as EGR. The exhaust gasses go right back into the intake, causing poor air fuel mixture quality for a terrible burn and everything is also much hotter. More overlap is not suitable for low rpm because of the same directly related reasons. But this effect is good at high rpm because volumetric efficieny at high rpm is better because exhaust gasses pull intake mixture into the cylinder faster allowing for a cleaner better burn. And the intake centerline also change up where engines make power. Typically you will see cams with 112-114 LSA grounded with a 3 or 4 degree advance for an intake bias for more low end power. So my cam has an LSA of 113 with a 109icl and a 117ecl. LSA is determined by adding the centerline and dividing by 2. Advancing a cam opens the intake valve sooner, hence why it builds more bottom end torque and chips away at the top. Retarding it does the opposite. Something else to understand is lobe intensity. Ideally you want a valve to open and close instantly. We cant do this yet but the faster you can do it, the better for power. Although its also harder on the valvetrain so there is a balance of power to be had but its ultimately your choice. Thats just a few basic things to know. There are many good reads of you google it. Isky cams has some insight as well on their site about their research.
Last edited by Mike TA; 06-15-2017 at 12:58 AM.
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Nope. Everytime I have tried to get down to Baytown with this car, the nearest track, it's something....kids got sports, or a cub scouts deal, of there is some family thing, etc. It got so frustrating to be honest I just hung up the idea for a while. Got the itch again though....
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i highly recommend reading the "why LSA doesn't matter" sticky
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Nope. Everytime I have tried to get down to Baytown with this car, the nearest track, it's something....kids got sports, or a cub scouts deal, of there is some family thing, etc. It got so frustrating to be honest I just hung up the idea for a while. Got the itch again though....
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Yep. Same thing. I tried to be involved...coach, be a cub scout leader, etc and I don't mind it, I like hanging with my little dudes. I finished that car over a year ago and think I put 1500-2000 miles on it since then. I'll make it out there at some point. Gotta keep them priorities straight. Need them kids to put me in one of the nice nut houses of I make it that long. Lol.
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Yep. Same thing. I tried to be involved...coach, be a cub scout leader, etc and I don't mind it, I like hanging with my little dudes. I finished that car over a year ago and think I put 1500-2000 miles on it since then. I'll make it out there at some point. Gotta keep them priorities straight. Need them kids to put me in one of the nice nut houses of I make it that long. Lol.
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Hi Mike, Im not trying to change the focus of your thread, i want to comment seems like you have a nice choice of hardware on that car, but being a M6 combined with those specific H/C/I, I would of guessed made more power on the dyno..like 460ish, those numbers to me seem more like 243 heads and that cam numbers..YES I know its a mustang dyno and they can be stingy.
EDIT: and numbers arent every thing ..sounds like fun ride!
EDIT: and numbers arent every thing ..sounds like fun ride!
Last edited by z28241; 06-15-2017 at 10:19 AM.
#15
I get what your saying here.... I think. So another question just to get your opinion. This cam is specifically advertised to be matched with at least 3.73 gears, I think 4.10 ideally. Is that why they suggest the lower gearing....to compensate for the loss of lower end power due to the longer durations and overlap? And the way I understand it is that this cam has a built in advance of 2 (hence the +2) to give it more intake biased. I am assuming, again, that is is to help offset the the loss of low end power due to the longer intake duration and resulting over lap as per your explanation above.. Am I even on the right track here? Sorry if this is elementary....just trying to visualize this in my head.
Yes your cam is advanced to give you a little more low end grunt. It makes power a little bit sooner and fall off a little bit sooner. (Again do you see everything is a trade off?) No advancing a cam doesnt help compensate overlap. If you were to add 6 degrees of retard into it the overlap will remain the exact same. It will just move your powerband to the right and decrease felt throttle response. Advancing will build more bottom end, take a bit off the top and increase throttle response. Altering when the intake opens and exhaust closes will determine overlap. More overlap will result in poor idle quality and vacuum. Things like AC and power brakes (which as we know are usually vacuum operated) will begin to not work as well. At a certain point, you will need to figure out ways to compensate so that your brakes work...
This stuff becomes extremely complex and you could easily write a 1200 page book on it, perhaps mutiple books with different theories and results. I dont think their is a single person here that could give you all the details, some of it is even kept secret. ESPECIALLY lobe design. But the basics are out there. They are very long reads, I think there is a pdf on google from a university about all this. It gives all the insight to how the 4 stroke engine works and what changing cam profile does to it. Still tough to get any info on lobe design. And of course everyone will tell you theirs is better then the next guys...dont get too hung up on it.
#16
Its not like their is a trick to cam selection. Just be honest with yourself. Just ask yourself, what am I using this car for? Do I want a hot street strip cam in a daily? Am I going for more Rpm? Do I want it to be well mannered? What kind of heads am I running? Do I want to change valve springs every 20000 or 80000? Will my heads and intake make power above xxxx rpm anyways? Can my bottom end take that much rpm?
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Hi Mike, Im not trying to change the focus of your thread, i want to comment seems like you have a nice choice of hardware on that car, but being a M6 combined with those specific H/C/I, I would of guessed made more power on the dyno..like 460ish, those numbers to me seem more like 243 heads and that cam numbers..YES I know its a mustang dyno and they can be stingy.
EDIT: and numbers arent every thing ..sounds like fun ride!
EDIT: and numbers arent every thing ..sounds like fun ride!
Last edited by Mike TA; 06-15-2017 at 02:37 PM.
#18
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BSpec, thanks a ton for the insight. I have been reading and to are right, the data can make your head spin. Honestly, I read some of it and when I'm done I feel more confused. To did a great way of explaining that in a way that was easy to understand.
I also get your point about getting a can based on what you honestly want. That what was great about working with Martin. We discussed things I wanted, what I was willing to live with, cost, etc. This is where we ended up. I know I will have to swap springs more often with this cam but I am completely comfortable with that.
If anyone else had anything to add I am all ears....
I also get your point about getting a can based on what you honestly want. That what was great about working with Martin. We discussed things I wanted, what I was willing to live with, cost, etc. This is where we ended up. I know I will have to swap springs more often with this cam but I am completely comfortable with that.
If anyone else had anything to add I am all ears....