one of the cams i tried in my 436 had 40deg of overlap,car wouldn't fall out of a tree for the first 300ft,after that i made good power.But the cam with 18 deg made just as much power up top and 3 times as much down low.I tried everything under the sun to make that cam work-just wouldn't
__________________ www.virginiaspeed.comcustom engines for street or race,tuning,installs,fabrication. check our our online store-i'm adding new products every day http://shop.virginiaspeed.com/main.sc757-468-5101 1979 Z28 Outlaw 10.5-670bbc twin promod 94's Crew Chief,engine builder,tuner of Phil Thomas's
LSX powered Mustang"The Renegade" 7.29, 198mph-best 1/8 et.4.70 @ 164mph 315 radials at 3275lbs
one of the cams i tried in my 436 had 40deg of overlap,car wouldn't fall out of a tree for the first 300ft,after that i made good power.But the cam with 18 deg made just as much power up top and 3 times as much down low.I tried everything under the sun to make that cam work-just wouldn't
That big of a difference from 22 degrees difference in overlap? Have you seen any difference going from a negative overlap cam to one with overlap? Is there a sweet spot?
one of the cams i tried in my 436 had 40deg of overlap,car wouldn't fall out of a tree for the first 300ft,after that i made good power.But the cam with 18 deg made just as much power up top and 3 times as much down low.I tried everything under the sun to make that cam work-just wouldn't
lol, that is how mine was. Its like the motor is running on 4 cylinders. I knocked 24* out and its a whole new motor.
I think there is power to be had with overlap, but it takes a really good setup/tuner. Some of the stuff Spetter did amazes me. The guy is a genious.
one of the cams i tried in my 436 had 40deg of overlap,car wouldn't fall out of a tree for the first 300ft,after that i made good power.But the cam with 18 deg made just as much power up top and 3 times as much down low.I tried everything under the sun to make that cam work-just wouldn't
Just went thru a similiar experience, the smaller cam I just put in kicks the shit out of the other. Had to leave on 13 PSI on the larger cam and it still wouldn't 60'. Thing sounded like a 757 on the line then left like a golf cart, lol. I'm squared up now at 8-9psi off the line with the new cam.
More food for thought that ties into Brian's comments. My 447 CU/106mm with 60mm WG takes the same amount of C02 to run the same boost he does, almost exactly.
Mark
__________________ 2009 combo Kurt Urban Performance 447 CU IN LSX-106 mm Turbo-Best 1/4 7.63@189.5mph----Best 1/8th 5.05@152 (3455lbs)
Just went thru a similiar experience, the smaller cam I just put in kicks the shit out of the other. Had to leave on 13 PSI on the larger cam and it still wouldn't 60'. Thing sounded like a 757 on the line then left like a golf cart, lol. I'm squared up now at 8-9psi of the line with the new cam.
care to clue us in on the specs or is this just more secret squirrel cloak and dagger?
I wish there was more data out there on turbo cams and the combo's they were used on. A sticky with everybody listing there setup would be nice. Even if they don't give away cam specs tell us what other parts are used and what shop spec'd the cam. Then track times and dyno numbers. Myself personally I am going to use Shawn at Va Speed.
More food for thought that ties into Brian's comments. My 447 CU/106mm with 60mm WG takes the same amount of C02 to run the same boost he does, almost exactly.
Mark
interesting...thanks for sharing
__________________ 1999 Pewter T/A | Just another slow drag radial car (see here) Virginia Speed 366ci LS2 + big turbo (the little block that could) | 7.99 @ 177.8 (1.36)
Virginia Speed 388ci LS2 + bigger turbo | In Progress
Special Thanks to TheOutlaw1, Phil99vette, Shawn @ Va Speed and MADMAN for all their help
care to clue us in on the specs or is this just more secret squirrel cloak and dagger?
Not going to give specifics because I don't know if my engine builder wants that out there,lol but I can tell you its a fairly traditional hydraulic roller turbo grind.
__________________ 2009 combo Kurt Urban Performance 447 CU IN LSX-106 mm Turbo-Best 1/4 7.63@189.5mph----Best 1/8th 5.05@152 (3455lbs)
care to clue us in on the specs or is this just more secret squirrel cloak and dagger?
It's not about being secret squirrel.It costs alot of money to figure this stuff out,i can tell you that i have tryed 6 cams in one engine-that isn't cheap.Guys like me and Kurt Urban(who built Mark's engine)do this for a living,this is how we make our money-us giving away the info we worked so hard for is foolish.Be happy that guys like us chime in on any topic and please be grateful for me or anybody else trying to steer people in the right direction.I could easily not say anything and just watch people go in the wrong direction.
__________________ www.virginiaspeed.comcustom engines for street or race,tuning,installs,fabrication. check our our online store-i'm adding new products every day http://shop.virginiaspeed.com/main.sc757-468-5101 1979 Z28 Outlaw 10.5-670bbc twin promod 94's Crew Chief,engine builder,tuner of Phil Thomas's
LSX powered Mustang"The Renegade" 7.29, 198mph-best 1/8 et.4.70 @ 164mph 315 radials at 3275lbs
...Be happy that guys like us chime in on any topic and please be grateful for me or anybody else trying to steer people in the right direction.I could easily not say anything and just watch people go in the wrong direction.
Shawn, I went back through your posts here and found basically 2 things. One was that the cam depends on the combo, which I think we pretty much all knew. The other was that 18 deg of overlap made more low-end than 40 deg overlap, which is kinda intuitive. Was there anything that I missed?
__________________ 1995 Z28
388 LT4, AFR 210's, Home built T-76GTS turbo system
TH-350, Vigilante 10.5", Ford 9"
Not going to give specifics because I don't know if my engine builder wants that out there,lol but I can tell you its a fairly traditional hydraulic roller turbo grind.
Oh NO, Your not getting off that easy, whats the specs man. You came in the topic now spill it, lol
__________________ 96 firebird
370ci ls1
Dart 250's CNC pro 1 heads
vic jr intake
custom single turbo kit
PT 91.5 turbo
dendibear powerglide
Be happy that guys like us chime in on any topic and please be grateful for me or anybody else trying to steer people in the right direction.I could easily not say anything and just watch people go in the wrong direction.
I don't know if you meant for that to come off condescending or not, but it sure did in a very big way.
I started this thread as a discussion on theory. I don't care about numbers. I do care about understanding the basic theory when it comes to dealing with the different pressure differentials seen by turbo vehicles. It is good to see people posting some information who have tried different setups but they lack any explanation of the theory. Saying you have done X and gotten Y result is useful to an extent but I'm trying to get an understanding of why.
Myself and my friend and fabricator 1320 have done a lot of testing at our own expense and time with rear mounts and shared the results, but it's just a hobby for us. Even with the free information provided and an explination of why, very few people actually follow it the first time around.
You could probably post exact cam specs that work the best for every combo on the planet if you had them and only one out of twenty people might copy them so you'd just be wasting your time typing any ways LOL. If you understand the theory or even if you don't but have formulated your own through testing, it would be informative to hear. Everyone's combination is different and even with knowledge of the theory getting the best setup will still need to be done through trial and error. Unless people are willing to take the cost of trial and error testing upon themselves they will need someone who has been there done that and knows what little tweaks work in which scenarios. That experience is not attainable from just theory and in my oppinion that is the real secret and money making knowledge. If you don't want to share any more than you have already because this is your main business and what puts food on the table, I understand.
Ironically I'm not even looking to change out my cam, just trying to get an understanding.
People guard their cam specs...period. I was lied to for years about one guys combo. It wasn't until I got to know him and bought the cam out of his motor did I find this out. I laugh about it now when I hear him talk to people...its all BS.
Not unless you want to experiment, get a cookie-cutter grind. Something that someone else has tried and worked. I opted to experiment. I'm on my third cam and countless months of zero return....it sucks! I did learn some stuff though.
People guard their cam specs...period. I was lied to for years about one guys combo. It wasn't until I got to know him and bought the cam out of his motor did I find this out. I laugh about it now when I hear him talk to people...its all BS.
Not unless you want to experiment, get a cookie-cutter grind. Something that someone else has tried and worked. I opted to experiment. I'm on my third cam and countless months of zero return....it sucks! I did learn some stuff though.
and if people can't understand why Shawn, Kurt, etc. don't want to share their cam specs...
Chad
I don't have a problem when people keep their cam spec's a secret. However, it bothers me when people come in to a thread and tout how much they know but offer no real theory or specifications. If you don't want to share your knowledge, then there's really no point in posting to begin with.
__________________ 1995 Z28
388 LT4, AFR 210's, Home built T-76GTS turbo system
TH-350, Vigilante 10.5", Ford 9"
I don't have a problem when people keep their cam spec's a secret. However, it bothers me when people come in to a thread and tout how much they know but offer no real theory or specifications. If you don't want to share your knowledge, then there's really no point in posting to begin with.
I see your point...but Shawn DOES help here quite a bit...and I at least appreciate it.
back on topic...anyone have any opinions on the Speed inc style cams?
Chad
__________________
Engine: heads/cam dart/torquerV2 stock bottom end HS rockers, ls6 intake Drivetrain: M6(soon to be A3) Moser 9 inch, strange pro case 4.11's Suspension: UMI LCA's/SFC's/PHB QA1's, midwest Chassis torque arm !front swaybar
Oh NO, Your not getting off that easy, whats the specs man. You came in the topic now spill it, lol
