Turbo camshafts
 

Do you need to be running turbo cams if your going to boost? Easy question, but I dont know the answer.

Re: Turbo camshafts
 

Yes, because we all know that your Non-Turbo motor won't even start without some Turbo cams in it if you put a turbo on the car!!!











But seriously, No you don't. Having them will open up your durations allowing the excessive air to flow into the cubustion chamber better, and flow out better. Giving you a altogether better turbo motor.

Re: Turbo camshafts
 

didint u post this same exact question on honda-tech? and by golly, u got the same exact answer

cool

Re: Turbo camshafts
 

lmao....um no :S

Re: Turbo camshafts
 

"Turbo" camshafts are just low duration, high lift units. This type of profile helps prevent reversion of the exhaust back into the head due to the turbo created backpressure. This is a good idea to use on a motor that creates a lot of low end torque mated to a quick spooling turbo setup. However, with most of the motors used by many of our list memebers, they don't really get into the power until the middle to upper rpms. Reversion won't really play that huge of a role in this aspect, since the motor's VE is characteristily low in this range.

This is just a general rule. But if you feel like you need to run a "turbo" cam, then try one out. Or better yet, ask a person that has run a stock cam and a turbo cam, to see what their impressions are on both.

Re: Turbo camshafts
 

Mild NA cams work well, too. Or really really hot NA cams. LS + Crower 404 + boost = teh win!

Re: Turbo camshafts
 

oh... i coulda sworn it was u... :1

Re: Turbo camshafts
 

The Gospel according to Corky Bell:

"Make no mistake in the fact that the turbo performance cams are very different from atmospheric performance cams. The characteristics of long duration and high overlap for atmo cams are unwelcome in the turbo system. The street turbo, which is generally small, operates on exhaust manifold pressure somewhat higher than intake boost pressure. This situation, when presented with long-duration, high-overlap cams, creates a huge amount of reversion. Thus the "turbo cam" tends to become a low duration, very limited overlap camshaft.."

RULE: It is hard to find a turbo cam that works better than the stock item.

Re: Turbo camshafts
 

So in other words better just to go with some Crower's or somethign like it other than turbo cams.

Re: Turbo camshafts
 

best to just stick with the stockers and up the boost

Re: Turbo camshafts
 

have been curious about this myself. once i build a bottem end and up the boost im sure i will want a cam. how many people on here are using after market cams. sorry to thread jack, but at least its relevant. lol

Re: Turbo camshafts
 

8)

my question, say i get a B16, it would be possible to run a Civic type R intake cam, and keep the stock exhaust cam, right?

Re: Turbo camshafts
 

I wondering the same question, im building up my z6 and wondering if i should go with a NA cam or TUrbo cam or stock, i have herd that you dont NEED to but with a aftermarket cam that you will just get more hp per psi

Re: Turbo camshafts
 

It's a shame Corky is a stupid idiot.

Re: Turbo camshafts
 

you run the b16 intake cam as the exhaust cam and the type ARRRR intake cam for the intake

Re: Turbo camshafts
 

For example, in the very first paragraph of the introduction to his famous Maximum Boost To My Wallet, Corkshite Bellcrap proudly proclaims that it is heat that drives a turbine.

Well, any riceboy with a blowtorch can prove that one wrong. Flow drives the turbine, pure and simple. Cork is an idiot.

Re: Turbo camshafts
 

Preach and Testitfy, that a boy

Re: Turbo camshafts
 

too bad turbo cams are big pieces of ----

Re: Turbo camshafts
 

hmm, umm go to the garrett website and look around, you'll find that they say the same thing, that it's heat and flow that drive the turbine. Now i wonder who knows more

joseph davis vs. corky bell & garrett

Re: Turbo camshafts
 

I do.

You can't drive the turbo with a blowtorch, but you can with flow from an air compressor.

Heat is a good way to store energy, but until it's made the thermodynamic conversion to PRESSURE it means ---- all, and has nothing to do with spooling a turbo.

Wet steam @ 450 deg F > equal mass of exhaust gas at 1500 deg F, for creating pressure. By several orders of magnitude.

Re: Turbo camshafts
 

Joseph, why don't you write a book on turbocharging? What is your backround anyways? I have known Corky for many years and he is about the smartest guy around. With out heat, a turbo will not work in a car, on a bench maybe but not a car.

Randy

Re: Turbo camshafts
 

You're not the only one in the last 24 hours to ask me to write a book.

http://www.honda-tech.com/zerothread?id=1225182&page=24

Turbines work without "heat," as you percieve it. Pressure-enthalpy conversions are a bit more complex than all that.

Give Corky my love, and ask him if he could get off his slack ass and return Dave Bennett's S2000 Helms? It's been a couple years, and Dave was calling pretty steady about it there for a while.

Re: Turbo camshafts
 

Joseph,
That's funny that you got asked about the book thing before. Why in the hell should I call Corky and ask about a deal between Dave and Corky. It's not my business and will never be. With my personal business with him has always been good.
I understand what you are saying about pressures. But in a gas engine like we run in our normal cars, heat makes pressure that drives the turbine. The book that he wrote was for the common man learning about street turbos. Not a engineer's handbook by any means.

Randy
P.S. My girlfriend is like a english goddest, so if you need her to read your ruff draft, she will.

Re: Turbo camshafts
 

Let me guess, you live local to him?

Nope, it's air displaced by a pump - the engine itself.

The flow (and all related dynamics ie quality of flow based on keeping close as possible to ideal port velocity) from compressor selection, plenum, IM runners, port design, combustion chamber, camshaft(s), manifold design, and turbine itself all determine flow, which is modified by the IM pressure and TIP (Turbine Inlet Pressure) as the engine goes through the rpm and load ranges. Flow is based on volumetric efficiency of the system, with an eye to pressure. The pressure being more determined by engine displacement and VE than heat, however.

Now, you say, heat is directly related to pressure. Well, yes, but for the purpose of a pressure-enthalpy conversion across a turbine (translation: the inefficient conversion of heat into pressure as potential energy gets lost all across the system, deflected by turbine restriction), no. You get further off of air displaced than off of heat energy entering the turbine. To correctly illustrate this, observe the 4th gen F-body asshats who can't find underhood room to mount a turbo, so they stick it behind the rear axle. At that point, most of the heat in the system is gone. ASSuming 1500 degree EGT, we can safely ASSume 80% of the temp differential above ambient is gone.

As far as di-rectally manipulating temperatures for pressure at a lower temperature, this can be done by way of fuel selection or water/diluent injection. Which further explains my point.

For a given airmass, in a given engine, you *always* make more power with alcohol than you do with gasoline, when adjusted for stochiochemic. Despite having to inject nearly twice as much alky as fuel, which somewhat displaces intake charge. There is no extra oxygen in alky, btw, so this is not a monopropellant effect such as the 20 mL hydrazine per gallon of gas for 10% more power trick. Alcohol burns cooler - less heat. In fact, some drag only domestics entirely fill their block and run no coolant, as they don't overheat at idle on alky, and the run down the track is too short to heat anything appreciable. You see where I am going?

Given enough water injection, you entirely do away with an engine's cooling jacket. At 1:1 ratio of water-fuel, it is not uncommon for the area of cyl head between valves to be sub-200 deg F. Same with piston faces. At 1:1 ratio, EGTs are significantly lower than regular pump gas - yet it is flow which is driving a turbine in this situation.

Yup. I've told a lot of people to buy that book, then forget everything theory-wise and prepare to relearn it. It [i]is[/i[ and excellent primer... but translating the language of machines into layman's terms always leads to misinformation. There is a reason why engineers use jargon.

There's also a flip side to it, which Co rky's fallen prey to. A majority of information in Maximum Boost is cited works Corky skimmed the overviews of, and used to prove his views. Views he didn't take the time to question and test to make sure they were valid. Not enough of it is his own blood, sweat, and tears.

Tell her I was terribly influenced by Bukowski, and I have a mouth like a toilet. :P

Re: Turbo camshafts
 

to get more direct to the actuall question (not that i dont like the debating) what ------- motor are you talking about?


instead of asking a generic question why dont you say what your actually doing with your setup.
id like to assume that the motor you have in your SN is what your actually running however thats usually not the case when you see a question like this. i dont know ---- about d series but on b vtec, id recommend at least type-r cams but never a "turbo" cam. on LS motors turbo cams are fine (anything is better than stock) but theres nothing wrong with 404's or 403's. in reality it has to do with how much duration you need is how high you need to rev. if you have a small turbo and a low rev limmit then use a low duration cam. if you have a big turbo and a high rev limit then use a high duration cam.

Re: Turbo camshafts
 

i had to go back and re-read everything you just said one more time. i could not possibly dissagree more with every word you said. its just not possible. in fact i really dont know what the point was. you seem to say that "turbo" cams should be high lift low duration but then you say that stock cams are better than turbo cams. i dont get it... but what i do get is that generalized answers are ------- gay. and as oftem proved hondas dont fall under the same rules of physics as other cars.

Re: Turbo camshafts
 

The book that Corky wrote was many years ago. It has been many many years ago that I read it. The thing he said was something like this. Turbo cams are different, than NA motors. Stock cams are pretty good for turbo motors. He said there was improvments with a special turbo cam. In a street not looking to make max power a stock cam should be fine. If you are trying to make huge power than look and talk to the cam grinders about there special turbo cams.

Randy

Re: Turbo camshafts
 

hey jcushing, everything falls under the same rules of physics...but i think i know what you meant by that, like other engines don't behave the same way as honda's when you change certain physical properties such as lift, duration, and so on

Re: Turbo camshafts
 

its a ------- joke lol, people think mainstream run of the mill turbo setups, not stupid honda people like us that slap huge turbos on small motors and run them to 9K+, for this you NEED the duration to keep making power. "turbo" or stock cams WILL NOT make power high in the RPM range

Re: Turbo camshafts
 

It's very difficult to get high lift in a B-series application. JUN 3's illustrate this perfectly.

Re: Turbo camshafts
 

But like you were saying Joesph you can use a NA cam and it will work ok on a turbo motor?

Re: Turbo camshafts
 

http://www.nonvtec.com/board/viewtopic.php?t=2380

12.23 in the quarter in a integra (DC) running moderate boost without vtec using super overlap crower 404 NA cams , you tell me if they work. (not like anyone ever ------- listens to me anyway WTF do i know)

and to decypher JD's always informative yet never directly answering points he means jun3's and similar cams (like Rockets) run into valve to valve clearance problems. theres only so much lift you can squeze out with a b series head

Re: Turbo camshafts
 

Back to the question at hand. Yes your stock cam will work when you put boost to it. I'm sorry all that Joseph and I got into it alittle, I hope there is no offense taken. If you need big power camshafts will help. I work on v8 crap all day long and cam-head combs make the power.

Randy

Re: Turbo camshafts
 

V8's also try to maximise cylinder filling and make as much torque as possible... whereas on a 4 cyl that just runs us into our knock limit quicker, as we don't have displacement to burn. What the 4 cyl guys do is try to move the powerband up so the torque peak is extended and doesn't drop off as quickly, and let mutant rpms manufacture googly-eyed hp figures while running nothing impressive by way of airmass per engine cycle/torque/cylinder filling.

Frankly, for B-series shooting for the usual 300-ish whp, I wouldn't look at a set of cams unless you were LS (they really do help with power from low to top end, spool, and keeping tq from falling off as hard up top) or if you were dead certain you had auto trans B16 cams. And, even then, I might not look into cams... you see plenty of people hitting 300 whp on stock block LS, it can be done.

BTW, iceracercrx, I didn't take any offense. I'm a socially inept neurotic, and really happy you don't hate me.

Re: Turbo camshafts
 

It takes a lot to make me hate someone. The ass hole that rear ended me last year in turn 10, I hate. After the race I figured he would come to say sorry or something. Nope all the dick could say is "I hit you pretty good because my brakes didn't work the whole race" ------- ass hole. Take it easy Joesph.
Randy