Exh. biased cams..

[Turbo6Smackdown]

Ok, just got done talking to a recognized expert in racing head building, and he had a couple questions about my cam. I told him what it was 206/210, and he was like "What??? Why is your exhaust bigger than your intake?" I told him the philosophy of why people go that route and it was like I was speaking swahili to him. He said no, that's absolutely not right at all. It's the exact opposite actually. You want to keep the combustion charge in the chamber longer, for more power.
This did make sense to me, but then, why do some known experts around here promote exhaust biased cams? In fact, he didn't even know what that term meant. I mean, when I said "exhaust biased" his face went blank. He's never heard of it in his life. Then he asked me why would you do something like that? I replied, that the idea behind it was, to prevent boost stacking, and he didn't even know what that was either. His reply was, that if your exhaust ports and runners were doing their job, you would never need a cam with more lift or duration on the exhaust side of the house. And this stumped me, because I didn't want to dismiss his logic, as he has quite a resume in the racing head department. He said, that there's not too much you could do, to a stock head casting from the 80's, and that he could "go over it" but it may not help much. So I asked him what he could do to a set of TA Performance heads, and he said he's never heard of that company.

So what do you guys think? Should I bring my heads to him? The only reason I considered him, was that he was close, and that he's done heads for really famous racers before.

 

[TurboDave]

You left out some details. You went on and on about how he's an expert in racing head technology, but..... How much expertise does he have in "turbo charged" head technology?? Since you didn't tell us who it was we're left with no info as to his expertise.

 

[jasjamz]

Why are you hiding his name and info? You have been on this board long enough to know that stock heads can make awesome power but you let him tell you different? Never heard of T/A, never did any Real Modded V8 Buicks then either. Pass on that guy. Send them to a well known TR Head Porter.

As far as the cam question, I used the search and found many threads on it. Over and hour of different opinions. I still boils down to the builder and driver.

 

[mikestertwo]

How much expertise does he have in "turbo charged" head technology??

+1

 

[bison]

He said no, that's absolutely not right at all. It's the exact opposite actually. You want to keep the combustion charge in the chamber longer, for more power.
This did make sense to me, but then, why do some

Tell him to just drop the compression ratio and run a large intake lobe and see how much more power he harnesses. You want to get as much of the inert gas out of the cylinder as possible without increasing reversion or you cant fill the cylinder with a fresh intake charge. What a dope. Fwiw i run a 218/224 (and its advanced a couple degrees so that must be really bad for it) in my hyd stock block engine. How much power has he made with his engines? Maybe he has the secret everyone is dying to find out. There is plenty you can do to chitty emissions heads that these engines came with stock. At least you werent fooled and came to the correct place to ask questions.

 

[Turbo6Smackdown]

I'm not "hiding" him per se, because I was never one of those guys to start drama, or even get involved. I never talk about anyone, and I feel guilty even saying certain things lol.
This was the person that started total flow heads in troy. You can read his resume online. He does indeed have quite a lot of experience, and then, I was doubting as to whether or not he was versed in forced induction cars, which I do know Turbo Dave, has MANY different dynamics than natural aspiration. But it was said he does, so I kept his advice in my head. Though, I knew some of you experts would chime in, which is exactly what I was hoping for
I knew you guys would confirm or deny, but I had a slight inkling you guys would deny, rather than confirm.
And yes, I have been around this scene enough to watch you guys make 9 second passes on ported 8445's before. You know that, and I know that, but apparently some others do not lol.
You guys know me well enough to know, that most of the questions I pose on here, I already know the answers to. I just want to see how many other angles there are on my knowledge, before I go ahead and implement it. Maybe I may have missed something. My old unit taught me to check, recheck, and check it again. Measure 3 times, cut once is my saying. I don't have the $ to experiment with mistakes. I wish I did lol. When I do something, it has to be done one time, or I'm out the whole season. So I come to you guys, to see the real deal holyfield. Thanks again Mike, Jaz, Dave & Bison.

 

[Nick Micale]

There is not a simple one answer to the debate of more or less intake on any engine, especially a turbo one. There are LOTS of variables to consider when choosing a cam for ultimate HP in a given build.

For most street engines, really does not matter much way to go. both work well. But when max HP is needed from a build that is constrained by class rules and other requirements, then it is very important to find the right cam.

So many times I see post of a person that just loves his specific cam that has more intake duration, and then another person will say the same thing about his cam with more exhaust duration? What would you expect someone to say about the cam he when he just spent $$$ for it? And they are both right, cams work for them as expected.

Any GOOD race engine builder does more than just turbo Buick engines, and has accumulated information and experience from all configurations, conditions and power levels over the years.

My personal interest has been turbo Buicks for over 20 years, so I have picked out cam choices and designs that evolved with our experience, testing and feedback.

We have tried as many as 5 or 6 different cams in a given engine to find the most HP in its operating range. Another similar engine with different heads did not like this "ultimate" cam.

We do know Stage, stock, TA and Champion alum heads have different flow characteristics and ratios between intake and exhaust. This is where we would spec different cams, but there are still many other factors to consider.

Another observation is that in recent years, lots of owners put together parts that may or may not work together very well. In the performance arena, the proper combination is crucial for power as well as reliability. Cam design and selection is one of these important factors.

 

[thadeal4real]

i did not speak on this matter lol jk but i do have a question what are your goals or tryn to do?

 

[Turbo6Smackdown]

Definitely. There are indeed many variables in turbo cars. Though, you're right; any good builder should have a rola-dex of results he has had in the past, or as in Bison, the biggest mental rola-dex on tap I've seen in a long time. This guy knew next to nothing. I was quite suprised, given his reputation. In a mild street build up, a standard, or biased cam will probably not make much of a difference. But like you said, if it's a car that absolutely has to be optimised, because of either the customer preference, or the class limitations, then sure, a ton of things have to be measured first, before a cam is chosen. I've already picked my cam, a revolution 206/210. It's already in. Bone stock heads. Will be fine for now I'm sure, but it's a cam that I chose, because I'm going to grow into it. I'll throw a set of ported stockers on next year probably.
But I went in this place, looking to check their prices, as I was very interested in utilizing them, and a little expert advice as well. What I got was a very overconfident, VERY disinterested person, that was wayyyy too busy to hear what I had to say, & answer my questions. Not the friendliest person I've ever met lol. Even if this guy was not friendly, I'd still use him, if he impressed me with his technical expertise and background. Now, I'm not soo sure. Ahh well. Just had to ask. Thanks guys.

 

[jasjamz]

You did the right thing. No harm in trying to find new people to help in your goal of world domination. My PM box stays in the 90% range because I'm always asking questions. LOL! Wait till you put those heads on and crank it up to 25psi...thats when the fun starts.

 

[Turbo6Smackdown]

World domination lol. You got it. This year, I'm going for porsches. Next year, ZR1's.. (with heads & a slightly bigger turbo)

 

[Mike Licht]

He said no, that's absolutely not right at all. It's the exact opposite actually. You want to keep the combustion charge in the chamber longer, for more power.

This statement bothers me a bit. I believe your guy is a good head porter but is shows me that he has no idea of why short lobes were used in the first place on turbo cams. Why would you not want to get the exhaust out of the motor? What he is implying is that having the exhaust lobe bigger opens the valve too soon? This tells me he has not bothered to check the event timing to see when things happen or keep up on current turbo technology.
Mike

 

[bison]

this tells me he has not bothered to check the event timing to see when things happen or keep up on current turbo technology.
Mike

+1

 

[novaderrik]

you don't just run a cam with a "bigger" exhaust lobe on turbocharged engines.
look at most of the best off the shelf cams for a small block chevy- or even any stock cam for a small block Chevy- and they will have more lift and duration on the exhaust side. people have been putting higher lift rocker arms on the exhast side of engines to help clear out the exhaust better since people started modifying engines for more power.

 

[Turbo6Smackdown]

This statement bothers me a bit. I believe your guy is a good head porter but is shows me that he has no idea of why short lobes were used in the first place on turbo cams. Why would you not want to get the exhaust out of the motor? What he is implying is that having the exhaust lobe bigger opens the valve too soon? This tells me he has not bothered to check the event timing to see when things happen or keep up on current turbo technology.
Mike

That's what I thought. But then, this guy has 20 times my experience too, which is why I took his knowledge in and retained it. But, your store Mike, is one of the reasons that made me double check, as I'm not too you would sell something in your store, that you didn't endorse, or thought to be too gimmicky. (it's one of your revolution cams I'm running) I remember talking on the phone with you, about cams, and you said "about 4 degrees more on the exhaust, is what should run the best." so that's what I went with. And I'm pretty sure Full Throttle knows a little more about turbo buicks than the head guy.
(though... I was a bit taken aback, on how a person of his caliber never even HEARD of exhaust biased cams. in fact, he questioned me on it, as if I was **** in' stupid for using a phrase I must have just "made up". the phrase illicited a look on his face like "what the bloody HELL are you talking about you stupid moron???")

 

[Mike Licht]

My experience with some of the best cylinder head guys is that most of them only have in depth knowledge of cams for the application they specialize in and very few of those really understand turbos. Even some "tech guys" at cam companies just regurgatate the old stuff they have been doing for 30+ years as gospel. If they have no personal interest in this type of thing very few try to learn it. Just my experience
ML

 

[BlownV6]

Sorry guys!! I get a good laugh every time I check this type of thread!! I really enjoy all this logic:biggrin: Mike

 

[Turbo6Smackdown]

That sounds about right Mike. Noone has the pride, and personal discipline, to sit down, and get good at their jobs. Noone cares about advancement, or wanting to be the best. I guess that's just a lost art these days lol. I say, if you're going to do something, be the best you can be at it. If you're going to do it half assed, then just don't do it at all.

 

[TTipe]

Camshfts

This thread is scarey.I have not seen back to back (identical & controlled conditions) test data from the same engine.The "OE"'s use software such as CFD ("Computational Fluid Dynamics"),ADAMS and some "cam specific" CAE applications to optimize a cam and valvetrain for best efficiency and driveability.Power is "VE" (volumetric efficiency) based on a cell map providing "MBT/LBT",spark,back pressure,ambient air temp,load factor (eddy current,waterbrake,mustang,etc).All factors must be identical except for the cam.There are tradeoffs across the rpm band which may affect the torque area "under the curve" and may even provide an optimal condition someplace in the torque curve.Lets get serious! Just measure CHAMBER PRESSURE across the torque curve and leave it that.Thats what GM does.

 

[Turbo6Smackdown]

I have not seen back to back (identical & controlled conditions) test data from the same engine.

Like Nick Micale did in post #7?