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Discussion Starter · #1 ·
There are plenty of engines with good cams in the zx's at the wrecking yard, but they are all non-turbo z's. Are these cams the same as on the turbo models? Will using a cam out of a non turbo engine hurt the performance? Also, can the cam be removed without pulling the engine?

My cam is badly worn from having clogged oil passages. They are cleared up now after using compressed air and flushing the engine many times. Plenty of oil gets up there. I even drove it from UT to CA and back 1500mi. no problem. It is running good now, and consumes very little oil, but I'm sure I'm not getting as much power with the worn cam.
 

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> There are plenty of engines with good cams
> in the zx's at the wrecking yard, but they
> are all non-turbo z's. Are these cams the
> same as on the turbo models? Will using a
> cam out of a non turbo engine hurt the
> performance? Also, can the cam be removed
> without pulling the engine?

> My cam is badly worn from having clogged oil
> passages. They are cleared up now after
> using compressed air and flushing the engine
> many times. Plenty of oil gets up there. I
> even drove it from UT to CA and back 1500mi.
> no problem. It is running good now, and
> consumes very little oil, but I'm sure I'm
> not getting as much power with the worn cam.

Leslie, i was told in no uncertain terms that a turbo has a very different cam profile than a NA engine. i even bought a spare motor just for the rallye cam in it, so my turbo could have better low end response. talk about false logic!! so now i have a great paperweight.
 

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> Leslie, i was told in no uncertain terms
> that a turbo has a very different cam
> profile than a NA engine. i even bought a
> spare motor just for the rallye cam in it,
> so my turbo could have better low end
> response. talk about false logic!! so now i
> have a great paperweight.

Don't hold me to this. But from what I have been told and from my basic knowledge the two motors are night and day. That Includes the camshaft. The turbo motor is 7 to 1 compression with a different acceptance of fuel and flow of gases. The reason that the cams are different falls back on the fact that with a turbo motor you must fire the ignition slightly retarded so detonation does not occur. The night and day differrence between the two is why experts do not recommend using the N/A version to add a turbo. Good luck in the hunt for a used turbo cam---------buy a new one if you have the extra to spend. Check Motorsport Auto in CA (714) 639-2620------they have 2 different turbo cams and both cost about $160 plus you will need a set of new springs for $100----another $160+ for new rockers and another $50 for lash pads.........remember when changing to a new cam you have to replace it all if you want it to last------good luck
 

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Discussion Starter · #4 ·
> Don't hold me to this. But from what I have
> been told and from my basic knowledge the
> two motors are night and day. That Includes
> the camshaft. The turbo motor is 7 to 1
> compression with a different acceptance of
> fuel and flow of gases. The reason that the
> cams are different falls back on the fact
> that with a turbo motor you must fire the
> ignition slightly retarded so detonation
> does not occur. The night and day
> differrence between the two is why experts
> do not recommend using the N/A version to
> add a turbo. Good luck in the hunt for a
> used turbo cam---------buy a new one if you
> have the extra to spend. Check Motorsport
> Auto in CA (714) 639-2620------they have 2
> different turbo cams and both cost about
> $160 plus you will need a set of new springs
> for $100----another $160+ for new rockers
> and another $50 for lash
> pads.........remember when changing to a new
> cam you have to replace it all if you want
> it to last------good luck

Does a cam really make a difference
on a turbo motor. I can see how it
would make a difference on a N/A
motor. As differing durations and
lifts would change air flow. But since
a turbo engine is pressurized isn't
it basically just waiting for the
valve to open?(the air that is) Any
enlightenment would help. This also
brings me to the subject of porting
things in a turbo motor. Same
principle, how can the air flow
smooth out in a turbo engine if its
basically static until the valve opens? Any help is appreciated.

Thanks

Carlos L.
 

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> Does a cam really make a difference
> on a turbo motor. I can see how it
> would make a difference on a N/A
> motor. As differing durations and
> lifts would change air flow. But since
> a turbo engine is pressurized isn't
> it basically just waiting for the
> valve to open?(the air that is) Any
> enlightenment would help. This also
> brings me to the subject of porting
> things in a turbo motor. Same
> principle, how can the air flow
> smooth out in a turbo engine if its
> basically static until the valve opens? Any
> help is appreciated.

> Thanks

> Carlos L.

Carlos, My vast knowledge is really in normally aspirated engines. I caught onto the Turbo concept fairly fast though. Yes, lift and duration are key in non-turbo engines for making horsepower. The entire concept of the turbo is increasing the amount of air and gas into the cylinder before it fires. The problem with turbo cams is that the lift and duration have to be precisely calculated to help eliminate detonation. Most of the turbo cams that I have seen usually have identical or close to the same lift configurations. The major difference between the different cams come in the duration. The Turbo cams are open a slight bit longer on the intake side than the exhaust, wheras the non-turbo cams are open longer on the exhaust side. An analogy for you between the two different engine configuration, firecracker in an open hand and one in a closed. One way you lose the hand and the other just a burn. The turbo being the closed hand seems to create the most destruction, both for HP and for engine meltdowns. If I had a choice of putting either cam in my turbo I would go with the cam that a respected turbo Z company recommended or the original Nissan gods put in it. As for the porting question. Porting and polishing only help to eliminate small distractions within the airflow-----adding to small increases in air flow rates. Porting is just the matching of to different surfaces( kind like a square peg in a round hole.) Polishing is the art of removing casting blemishes within the intake and chambers to free air flow. As I stated an art. If you polish to much the air and gas will not atomize for optimal firing. Atomization is partly why the turbo creates all those horsies. Or maybe I am wrong!!!!!
 

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The Turbo cams are open a slight bit longer on the intake side than the exhaust, wheras the non-turbo cams are open longer on the exhaust side.
As for the porting question. Porting
> and polishing only help to eliminate small
> distractions within the airflow-----adding
> to small increases in air flow rates.
> Porting is just the matching of to different
> surfaces( kind like a square peg in a round
> hole.) Polishing is the art of removing
> casting blemishes within the intake and
> chambers to free air flow. As I stated an
> art. If you polish to much the air and gas
> will not atomize for optimal firing.
> Atomization is partly why the turbo creates
> all those horsies. Or maybe I am wrong!!!!!

Mmmm, mostly right. You are right about the cam, the longer intake duration does help fill the cylinder more, since you are supplying pressurized air. Since you are not relying on just the piston to fill the cylinder, which creates the most vacuum at the end of the stroke. Whereas with forced induction, you are cramming the cylinder with air/fuel from the moment the valve opens. With forced induction and fuel injection, a fully polished manifold would not hurt, it only helps this process. Many people try extrude honing (a process in which an abrasive putty is pushed through the head/manifold) to provide a blemish free surface and to open up the chambers. With direct port fuel injection, the injector supplies all the atomization you need, and the velocity of air ensures a good mix.
This is different from n/a engines where fuel atomization is helped by slight imperfections in the manifold/head, to 'stir up' the air a little, and prevent fuel droplets from forming. This is because you are relying on engine vacuum to provide all the air velocity, which increases and decreases according to piston position. This is not the case with forced induction.
 

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Discussion Starter · #7 ·
Will this Crane Cam work in my Turbo App?

Crane Cam# 168-0012
7. Good idle, daily performance usage, good low and mid-range HP, autocross, rallying, 10.0 to 11.5 compression ratio advised. Basic RPM 2200-5600

Degrees_____Degree____Degree_______Open/Close ____Gross
[email protected]___Advertised [email protected] Cam Lift _Lift
050_________Duration____Separation____Int./Exh________Int./Exh.
Int./Exh._____Int./Exh.
226 a _______272 _______110__________ 8 38__________ .450
236 a _______282_____________________53 3 __________.450

This is the Cam I have. I have not put it in yet, the motor isn't done yet... But you seem to know a good deal about cams, please tell me if you think this will work. I was told it is for Turbos.
 

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What is your engine??

> Crane Cam# 168-0012
> 7. Good idle, daily performance usage, good
> low and mid-range HP, autocross, rallying,
> 10.0 to 11.5 compression ratio advised.
> Basic RPM 2200-5600

>
> Degrees_____Degree____Degree_______Open/Close
> ____Gross
> [email protected]___Advertised
> [email protected] Cam Lift _Lift
>
> 050_________Duration____Separation____Int./Exh________Int./Exh.
> Int./Exh._____Int./Exh.
> 226 a _______272 _______110__________ 8
> 38__________ .450
> 236 a _______282_____________________53 3
> __________.450

> This is the Cam I have. I have not put it in
> yet, the motor isn't done yet... But you
> seem to know a good deal about cams, please
> tell me if you think this will work. I was
> told it is for Turbos.

This depends on what type of engine you are running. Give us some specs on your engine, such as compression ratio, valve size type of exhaust etc...
 

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Discussion Starter · #9 ·
Re: What is your engine??

> This depends on what type of engine you are
> running. Give us some specs on your engine,
> such as compression ratio, valve size type
> of exhaust etc...

Sorry, I got ahead of myself...
Turbo Block/Pistons, Internaly ballance (from ballancer to Flywheel)
P90 Head, with above cam. Honed and Blueprinted
N42 Intake manifold (No EGR stuff!!)
Stock Turbo at about 12lbs boost
3inch from downpipe back no cat no muffler
Stock ECU
Adjustable Fuel Pressure Regulator (+10-20lbs)
Saab Turbo APC system (monitors knock and adjust for maximum boost)
Bosch BOV
Starion Intercooler
Electronic Overboost Pressure fule cut off switch @ 18lbs
Possible boost tiggered Water induction system.

I think that is all the stuff I have. If I remember anything I will add it. But what do you think so far? Oh most of this stuff is in boxes in my garage waiting for the block to be finished. But as soon as I get it back, I will start getting photos for my web page.

Bean Bandit
 

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I don't think it's a good idea

> Sorry, I got ahead of myself...
> Turbo Block/Pistons, Internaly ballance
> (from ballancer to Flywheel)
> P90 Head, with above cam. Honed and
> Blueprinted
> N42 Intake manifold (No EGR stuff!!)
> Stock Turbo at about 12lbs boost
> 3inch from downpipe back no cat no muffler
> Stock ECU
> Adjustable Fuel Pressure Regulator
> (+10-20lbs)
> Saab Turbo APC system (monitors knock and
> adjust for maximum boost)
> Bosch BOV
> Starion Intercooler
> Electronic Overboost Pressure fule cut off
> switch @ 18lbs
> Possible boost tiggered Water induction
> system.

This cam #168-0012 is for Non-Turbo, high compression engines. If we look at the specs, we can see why.

.450lift/272 Intake duration, 282 Exhaust duration.

This is referred to as a split-duration cam, because the intake and exhaust operate on different durations. The exhaust is open for 10 more degrees than the intake. This means the exhaust is allowed to 'scavenge' the cylinder which means it pulls more air out of the cylinder while the intake is opening, creating a higher airflow. Instead of the cylinder filling relying on just the piston movement to create vacuum, the open exhaust valve aideds the incoming charge, in a sense this is like having a turbo that sucks the exhaust gas out. This creates a denser charge which = more hp. Of course these are usually not 'street legal' because some unburnt fuel is sucked out the exhaust because both intake and exhaust are open at the same time for a longer period of time. Not good for environmental reasons. You also need the high compression, because this is what creates the air velocity needed for the cam to work properly.

In regards to a turbo, this cam is not ideal IMO. For a turbo, you don't need a high lift (.450 is ok) or long EXHAUST duration cam. You WANT a cam with a longer INTAKE duration. This is because the 'boost' is doing all the work. You no longer rely on the piston to create a vacuum, and exhaust scavenging is not as important. The boost pressure is greater than what the piston/exhaust could create on it's own naturally, and this is why a longer intake duration is beneficial. It allows you to cram more air and create a denser charge which = more hp. A turbo exhaust BEFORE THE TURBO isn't as free-flowing as it would be in a n/a engine. This negates some of the effect of scavenging that I mentioned above. The turbo is actually causing the restriction. But, the turbo more than makes up for this in providing 'positive displacement' or boost.

My advice to you is to install your engine, and get it running first. Get used to the power, and add more goodies later on. I would strongly urge you to avoid the water injection, as this has been known to cause hardening and pitting of the heads. (The aluminum alloy has a high copper content which reacts with the steam and creates pitting.)
There are alot of products out there that can control boost electronically, and automatically retard the timing such as MSD-6BTM. This coupled with the intercooler should be more than safe to run @12psi and higher. A bigger intercooler and larger turbo would allow even higher pressures. Of course then you need to make sure enough fuel is being supplied.

Get some other opinions also, I'm not the be all end all of cams.

You want to sell that cam???
 

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Re: What is your engine??

Well Bean Bandit, sounds like you have a lot of trick stuff for the hop-up. Your stats on the cam became messed up and I am having trouble reading what duration was for the intake and the exhaust. Crane is a good cam manufacturer, however a 10:1 recommeded compression is ridiculous for a Turbo Z. Top End Performance does not even modify past 8:1 even with their engine mods. A stock non-turbo car with flat top pistons came as 8:1, but most Turbo and non-turbo engines had the dished piston which had a 7.5:1 ratio. The thing you want to remember with the Turbo cams is the Duration or open time on the intake side need to be longer than on the exhaust side. Lift can be disputed by many, but I recommend the lift being very close on each valve or a little larger on the intake side. Can you repost the cam specs not is a table form please.
 
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