Buick 455 cam question

[SuperBuickGuy]

Would you put a cam in for a future upgrade, or put the best cam in now for the application and swap cams when (if?) the upgrade happens?

Someday, I'll turbo the 455. Of course, there's not been a manufacturer that I've found that isn't a) trying to square peg/round hole with their cams; or b) suggesting a custom grind based on a 454 or 460 turbo race car. Both those idea have some problems, and I'm fortunate enough to have a great cam grinder in my neck of the woods... so

are NA and turbo cams close enough in specs to be interchangeable for street duty?
if not... what should I look for?

[Stich496]

I'd get a cam for what you are building NOW, tomorrow may never come, the turbo might never get bolted on.. you might sell it before you get that far,
but I would get a roller now, if the moneys there.. the cams arnt that much but the lifters are

[Beagle]

Richard Holdener has done a lot of builds with "non-turbo-friendly" cams and made some serious oats with boost. That's on Westech's dyno though, I think Petersen pubs paid for that building. He did manage to get an LX fox to run over 190 with a belt driven turbo (paxton I think) in Nevada about a million years ago, though, so I kind of like his work. Regardless, it leads me to question the whole "turbo cam" philosophy.

I'd probably look at something like the roller that Randal put in but maybe a little smaller. Maybe he'll chime in with how it idles. One thing a "turbo" cam should be pretty good at is kitten smooth idle. They'll never see it coming.

[A/Fuel]

Whats your ETA on "someday"?

[Bamfster]

You need to look at the whole package as well as end game too ....

I can comment on Randal's idle .... for that cam, it is pretty smooth .... daily driver smooth IMO.

[TheSilverBuick]

I'd get a cam for what you are building NOW, tomorrow may never come, the turbo might never get bolted on.. you might sell it before you get that far,
but I would get a roller now, if the moneys there.. the cams arnt that much but the lifters are

Wrong. The roller cam is almost twice as much as the roller lifters for the Buick, the lifters are actually priced on par with big block chevy lifters. I'm already considering a cam swap because as Bamfster says, the idle is pretty smooth, but the cam cost is (harden core then grinding) is doesn't make it a simple choice. BTW, you'll need the TA dual groove cam bearings to run a roller cam because they do not have the oil groove cut into the cam.

For a BBB, I'd get the the turbo cam from the start, I hear they are pretty torquey cams off the turbo, and that should really make the car a kick in the pants (literally) to drive.

My cam is tiny, thinking of going up in lift and stuff accordingly, but want most the power gain below 6,000rpm.

Hydraulic Roller with a 4-7 swap -Probably the smallest roller cam TA has made
VALVE LIFT
STOCK 1.55 RATIO:
IN: .512”
EXH: .512”
DURATION
AT .050
IN: 232
EXH: 232
ADVERTISED
IN: 298
EXH: 298
LOBE CENTER: 110

**Also, if I go to more lift and such, I may have to upgrade to the aftermarket roller rockers. I think TA said mine is the only roller cam they've sold that they know is using the stock stamp steel rockers, and they figured it'd be okay due to the low lift and such. SuperBuickGuy I think is looking at the Edelbrock heads, so he'll have a chevy selection.

[SuperBuickGuy]

Whats your ETA on "someday"?

a hair past later

And Randal



I have them

Hydraulic Roller with a 4-7 swap -Probably the smallest roller cam TA has made
VALVE LIFT
STOCK 1.55 RATIO:
IN: .512”
EXH: .512”
DURATION
AT .050
IN: 232
EXH: 232
ADVERTISED
IN: 298
EXH: 298
LOBE CENTER: 110

You have a strange definition of tiny. Most don't realize that stock is somewhere around .438 lift, 116 LSA, and 216 duration @ .050 (IIRC).....

RPM range - I'm not going above 5500 rpm.


why did you do the 4-7 swap? you're port efi right?

[TheSilverBuick]

Even my Centurion has .454" lift, and that was the isky medium cam. The 118 cam I think has around .465" and the 212 around .480".

I think most their roller cam's are ground around .600" lift for non-lifter braced applications and then higher than that for the full race applications. I'm thinking of going up to something with similar lift as Squirrel's, which is in the .550 range. I think the EFI takes some of the lope out of the cams. The 118 Cam loped a little with the Q-jet then not at all with the EFI, same with the 212, 800 rpm idle for either of them was no problem. This current cam gets a bit lopey at 800rpm, but is good at 900, but I haven't played with the fueling/ignition much at 800rpm either.

Ah, yes you do! Your pictures don't make it through the firewall at work, but I took a quick peak on my phone at your Skylark's project car thread.

[BBR]

RPM range - I'm not going above 5500 rpm.

Yeah, right. They all say that at first.

Small?

Mine is medium sized for a BBF.
LIFT..685/.685
DUR @.050: 260/270
DUR: 290/305
LOBE CENTER: 108

I'd play around with some dynamic CR calculators to see what the cranking pressure would be with the different cams.

[TheSilverBuick]

I started Drag Week shifting at 5,000rpm, ended shifting at 6,000rpm (with a KABOOM!)

[TC]

According to guys like Duttweiller and Urban, there is NO MAGICAL TURBO CAM..........They say build the motor like you would do NA and then put the turbo(s) on it...... Even the idea that you have to run a LSA around 114 is thrown out the window......

So what you should be doing is finding a cam for the operating range you want to run in.........Personally I'm going to go with a cam with somewhere around a 280-290 advertised duration with a .575-.600ish lift.......Though I will probably go with a LSA somewhere around 112, since wider LSA's do tend to have broader power ranges and flatter torque curves.......

[dieselgeek]

According to guys like Duttweiller and Urban, there is NO MAGICAL TURBO CAM..........They say build the motor like you would do NA and then put the turbo(s) on it...... Even the idea that you have to run a LSA around 114 is thrown out the window......

So what you should be doing is finding a cam for the operating range you want to run in.........Personally I'm going to go with a cam with somewhere around a 280-290 advertised duration with a .575-.600ish lift.......Though I will probably go with a LSA somewhere around 112, since wider LSA's do tend to have broader power ranges and flatter torque curves.......

I take Duttweiler seriously.

I've been arguing lately with my turbo supplier, he thinks any overlap is bad even if there is a 1:1 pressure ratio (theoretically impossbile, and YES I have measured drive pressure on more than one turbo installation, it's the measurement accuracy that's nearly impossible to achieve).

Meanwhile, last weekend I attended the ADRL World Finals in Texas. I noticed that the turbo cars there definitely ran cams with less lobe sep (it's easy to "hear" the difference, at least to me). I could tell by the lazy spooling that these were also likely 1.5 or 1.2:1 pressure ratio combos... it takes ignition tricks (or other secrets) at the starting line to spool a low pressure ratio combo... this I also know.

I still think there's room for improvement as most of the ADRL turbo cars in 10.5 extreme and Extreme Pro Mod were getting their asses handed to them by the blower and nitrous guys.

Just an observation.

[A/Fuel]

According to guys like Duttweiller and Urban, there is NO MAGICAL TURBO CAM..........They say build the motor like you would do NA and then put the turbo(s) on it...... Even the idea that you have to run a LSA around 114 is thrown out the window......

So what you should be doing is finding a cam for the operating range you want to run in.........Personally I'm going to go with a cam with somewhere around a 280-290 advertised duration with a .575-.600ish lift.......Though I will probably go with a LSA somewhere around 112, since wider LSA's do tend to have broader power ranges and flatter torque curves.......

Interesting....
But then you also said this:

Fully aware of the specs that they run, which is why I wonder why he isn't running similar ones.......If his cam specs where close to what they run in ProStock he'd have to run a wide LSA because the durations are so big, but he's not running a cam with 290-300 duration at .050 or 1.000"+ lift, is he??...... So tightening up the LSA may bring him more power........especially if he's running something like 114 or 116........Put it this way the cam for my weepy old small block has 270/278 duration at .050 and has a 103 LSA.......

The reason I went with the 103 LSA is because it will create a shit load of cylinder pressure and cylinder pressure equates to horsepower........It also tightens up the powerband and increases mid-range torque at a small sacrifice to peak horsepower, but face it our motors spend more time down the curve than at peak Hp, so the added power you get down the curve with a tighter LSA should equate to better ET's(acceleration).........And another benefit will be that the engine will RPM faster(quicker) and have a way snappier throttle...........

http://www.bangshift.com/forum/showthread.php/30579-Bench-racing-bore-and-stroke/page8

Would you be so kind to clear this decrepancy up?
Thanks.

[TC]

Interesting....
But then you also said this:

Fully aware of the specs that they run, which is why I wonder why he isn't running similar ones.......If his cam specs where close to what they run in ProStock he'd have to run a wide LSA because the durations are so big, but he's not running a cam with 290-300 duration at .050 or 1.000"+ lift, is he??...... So tightening up the LSA may bring him more power........especially if he's running something like 114 or 116........Put it this way the cam for my weepy old small block has 270/278 duration at .050 and has a 103 LSA.......

The reason I went with the 103 LSA is because it will create a shit load of cylinder pressure and cylinder pressure equates to horsepower........It also tightens up the powerband and increases mid-range torque at a small sacrifice to peak horsepower, but face it our motors spend more time down the curve than at peak Hp, so the added power you get down the curve with a tighter LSA should equate to better ET's(acceleration).........And another benefit will be that the engine will RPM faster(quicker) and have a way snappier throttle...........

http://www.bangshift.com/forum/showthread.php/30579-Bench-racing-bore-and-stroke/page8

Would you be so kind to clear this decrepancy up?
Thanks.

It all depends on your setup and what your trying to do and how the car is setup, going with a tight LSA is fine as long as the rest of the car is setup to accommodate its narrow peaky power band......So basically you can't take what works for one motor and apply it to all motors, you just have to see what works for your application........

[TC]

I take Duttweiler seriously.

I've been arguing lately with my turbo supplier, he thinks any overlap is bad even if there is a 1:1 pressure ratio (theoretically impossbile, and YES I have measured drive pressure on more than one turbo installation, it's the measurement accuracy that's nearly impossible to achieve).

Meanwhile, last weekend I attended the ADRL World Finals in Texas. I noticed that the turbo cars there definitely ran cams with less lobe sep (it's easy to "hear" the difference, at least to me). I could tell by the lazy spooling that these were also likely 1.5 or 1.2:1 pressure ratio combos... it takes ignition tricks (or other secrets) at the starting line to spool a low pressure ratio combo... this I also know.

I still think there's room for improvement as most of the ADRL turbo cars in 10.5 extreme and Extreme Pro Mod were getting their asses handed to them by the blower and nitrous guys.

Just an observation.

I think some of the problems with Turbo cars is people don't know how to size the turbos properly.......There is much information about sizing the Compressor side of the turbo, but there is very little info on sizing the exhaust(turbine) side of the turbo.......I think the biggest factor is the exhaust A/R, if it's to small you spool up instantly, but the turbo runs out of poop on the top end, go with to big of an A/R and the turbo lags in the lower rpm's.......So it becomes a fine line of balancing the spool time on the turbo with the power range of the motor.......

Now saying that and after months of researching Turbo sizing, I've come up with what will work good with my twin turbo build.....I had already figured out that a pair of 61mm turbos would be good for my application, but it was the exhaust A/R that I wasn't sure of, I had finally broke it down to running somewhere around a .82 A/R on the exhaust.......Which brings up my old engine builder buddy Rick that I just got back in touch with, he confirmed that twin 61's work good in twin turbo applications and he also said an exhaust A/R of .82 would be just about right for my application......So I guess I now know what kind of turbos I'll be running.......Funny thing is I'll probably be taking my block and stuff to him in Colorado to have the machine work done, since his shop has all the latest CNC machines for doing the machine work and he's been doing this stuff for well over 20 years on a daily basis and he's a guy that I trust!!!.........