Vt stage II cams + blower=?

Sash · #1 10-13-2006, 01:02 PM

Hey guys,at best of my knowledge and long time research I come to the answer that this cams are not gonna work whit the blower, 108 LSA cam is not good for the blower because overlap to the valves,apparently all of the boost gonna go true the exhaust valve,and I was cool whit that until I come across to this video,
read the mods on the mustang.....
<link removed for content>

GreenMonster'96 · #2 10-13-2006, 01:24 PM

Before the video link gets pulled - street racing video isn't allowed to be linked or posted, IIRC.

Just because someone did it doesn't mean anything... you don't know where they got their information or who recommended what or why.

It's your car so you can obviously do as you please. However, the overlap on the Stage II N/A cams is too great for a FI application. Ask VT, they spec'd the N/A cams and FI cams the way they did for a reason.

Less over lap helps to build cylinder pressure at the cost of reducing the inertial input of the exhaust gases at higher rpm. This works in a FI car because the inertial input is not as critical because the incoming intake charge is pressurized. Cylinder pressure is power, period. Anything you can do to increase cylinder pressure is good. Large overlap cams on an NA application use exhaust gases to "prime" the intake charge - provide the additional force on the intake charge and increasing the overall charge velocity. This affect increases with rpm because under load with increasing rpm the exhaust gases gain velocity (which corresponds to increased inertia).

Sorry for the long post, but basically, just because someone did it, doesn't mean it is right. And he should've pulled much harder on that Supra with 10psi on a cam'd motor.

Mustang03 · #3 10-13-2006, 01:25 PM

he would make more power with stock cams though because of the overlap, you can get away with stage 1's, but stage 2's can burn up a valve

Sash · #4 10-13-2006, 01:54 PM

I am sorry for the street race video,The reason I post it was to show that that guy is running the stage two N/A cams,I know is not right to run this cams whit the blower but this guy did and hi made good power to, 430+ rwhp,once again I am sorry for the street race video,this video have a different purpose.

ThatOrangeGT · #5 10-13-2006, 03:44 PM

even if you did leave the cam in the car, they would eat up ALOT of boost. You would wind up pullying the car up to like 12 lbs just to get to 8.

Triisomy21 · #6 10-13-2006, 04:46 PM

He knows about his cam situation. He's fully aware that he's not making as much as he could but I think he put them in before he got the blower.

But yea, not really an ideal set up.

#7 10-19-2006, 09:01 AM

I had a friend send me a PM on another forum and thought I would post on here, as there are a few common misconceptions stated, and the video/the car are mine.

The stage 2 cams run very well on a FI car, just not as well as FI cams. They certianly make more power than the stockers, and you do NOT have to pulley up the blower to make the same boost levels. They really make a big difference up top, as even before the vortech the car pulled right to redline, instead of falling off at about 5500 RPM.

I got the cams about a year before I got the blower, and VT engines, along with MPH, assured me that so long as I was not trying to make big numbers (aka staying within the limits of the stock shortblock) I would be fine.

For reference here, the car currently has a 3.60 pulley on it (stock from vortech, supposed to be 8~ PSI) and the autometer boost gauge JUST barely touches 10 PSI (might be more like 9.75) at the fuel cutoff at 6200 RPM.

The car made 383.7 (corrected) WHP and 375.5 RWTQ (corrected) on a mustang dyno, and from both the dyno shop and MPH I have been told this is the equivilent to about 420 to 425 WHP on a dynojet 248c. (about 10 percent difference). This is on a VERY conservative tune (light timing, 11.8~ a/f ratio). I thought of pushing it harder, but on a non intercooled car with the factory shortblock I was scared. Another thing to consider is that this is thru the TKO 500, which I assume is gonna dyno slightly lower due to heavyer rotating mass (maybe?)

one last thing, the car still has the STOCK VORTECH intake, aka no powerpipe. I dunno where the myth came about that stage 2 cams would eat up boost, but it simply is not happening in my case.

CompOrngGT · #8 10-19-2006, 09:40 AM

Quote:

Originally Posted by 2000gt4.6

The stage 2 cams run very well on a FI car, just not as well as FI cams. They certianly make more power than the stockers, and you do NOT have to pulley up the blower to make the same boost levels. They really make a big difference up top, as even before the vortech the car pulled right to redline, instead of falling off at about 5500 RPM.

For reference here, the car currently has a 3.60 pulley on it (stock from vortech, supposed to be 8~ PSI) and the autometer boost gauge JUST barely touches 10 PSI (might be more like 9.75) at the fuel cutoff at 6200 RPM.

one last thing, the car still has the STOCK VORTECH intake, aka no powerpipe. I dunno where the myth came about that stage 2 cams would eat up boost, but it simply is not happening in my case.

I think your car is a freak to be making 10#'s of boost with NA cams, 3.60 pulley and no p/p. Or your boost gauge is wrong... There's no myth about NA cams eating boost, it's simple physics.

PhatDoggy · #9 10-19-2006, 10:17 AM

Quote:

Originally Posted by 2000gt4.6

I dunno where the myth came about that stage 2 cams would eat up boost, but it simply is not happening in my case.

Not a myth. Here's how it works...

those cams have a fair amount of overlap in them, which is when the intake valve opens and the exhaust valve is still closing. During that time, you've got a pressurized charge coming into the cylinder, and blowing right out the exhaust (remember, it's still open). The point of forced induction is to put MORE pressure in the cylinder, and you're doing that, but you're losing whatever volume is introduced while the valves are both open. A stock grind or blower grind would not have as much overlap.

Boost pressure is manifold pressure,which is apparently not dramatically affected. If you were to measure cylinder pressure, I'm sure it's less than it would be with a "proper" cam.

The fact that you're making decent power says it's not as bad as it theoretically should be, or the dyno was set to read high (it happens) to satisfy the dyno racers.

Congrats on making it work.

GreenMonster'96 · #10 10-19-2006, 11:31 AM

Quote:

Originally Posted by 2000gt4.6

I had a friend send me a PM on another forum and thought I would post on here, as there are a few common misconceptions stated, and the video/the car are mine.

The stage 2 cams run very well on a FI car, just not as well as FI cams. They certianly make more power than the stockers, and you do NOT have to pulley up the blower to make the same boost levels. They really make a big difference up top, as even before the vortech the car pulled right to redline, instead of falling off at about 5500 RPM.

I got the cams about a year before I got the blower, and VT engines, along with MPH, assured me that so long as I was not trying to make big numbers (aka staying within the limits of the stock shortblock) I would be fine.

For reference here, the car currently has a 3.60 pulley on it (stock from vortech, supposed to be 8~ PSI) and the autometer boost gauge JUST barely touches 10 PSI (might be more like 9.75) at the fuel cutoff at 6200 RPM.

The car made 383.7 (corrected) WHP and 375.5 RWTQ (corrected) on a mustang dyno, and from both the dyno shop and MPH I have been told this is the equivilent to about 420 to 425 WHP on a dynojet 248c. (about 10 percent difference). This is on a VERY conservative tune (light timing, 11.8~ a/f ratio). I thought of pushing it harder, but on a non intercooled car with the factory shortblock I was scared. Another thing to consider is that this is thru the TKO 500, which I assume is gonna dyno slightly lower due to heavyer rotating mass (maybe?)

one last thing, the car still has the STOCK VORTECH intake, aka no powerpipe. I dunno where the myth came about that stage 2 cams would eat up boost, but it simply is not happening in my case.

Ok, I edited this because there was a lot of ranting. I will say this, and I'm sure Scott from VT will agree because I've seen him say it more than once on these forums. You have the wrong cams for your set up, period.
Do not come here and try to dispell "myth" without presenting some factual data. Dyno numbers adjusted for another type of dyno won't work... you can't just add 10% to Mustang numbers and call them Dynojet numbers.

As I stated in my original post, just because someone did it doesn't make it right. Myth about eating boost? No myth... its been explained by me and Keith. How your stuff is working the way it is... I can't explain because I can't take your word that it's really working that way. The stars must have aligned. Maybe two wrongs really does make a right...

#11 10-19-2006, 11:52 AM

You can supply all the "information" you want, but I am only telling you the real world results. Apparently I am the first person to do this on this forum (and the one I frequent) so I think I am at least a little qualified to tell you what to expect. Both VT and MPH via phone have said that the cams will make more power than the stockers, and I think from the RWHP number that is evident.

The boost gauge is an autometer, and with the power I am making, I cannot see how it could possibly be off. There isn't much of a chance a exhaust/intake car making only 8~ PSI with no intercooler could make 400+ to the tire on a set of cams that make less/the same as the stockers (as you claim)....

The dyno is a mustang dyno, so if anything it is reading low. If the dyno is "set high" then every dyno in st louis must be, because there are people that have dynoed on all three (that I know of) and the 2 dynojets read the same, while the mustang dyno was about 10 percent low. In addition, most of the "friendly" dynos are set this way because they want people to come back. The dyno shop didn't do any of the install/tuning, so they had absolutly no reason to fudge the results, regardless of the fact that its a mustang dyno. You don't install a mustang dyno in your shop if your looking to impress customers with high dyno numbers...

For reference, the car (mine) made 280 WHP on one of the dynojets in st louis, with full exhaust/cams/intake boltons and u/d pulleys. If anything, that number is low for a car setup this way, as I have seen claims of 290+

In other words, it isn't loosing the boost like it is "supposed to" and it's making more power than the stock cams should. Either the cams don't eat boost like you say, or they make much more power than the stockers, or a combonation of both.

BTW, by "conservative tune" what I mean is I have timing pulled to keep the WHP number where it is, and I could have gone leaner on the a/f ratio. I am unsure how much is left in the car, but both the dyno shop and MPH said there was more there, however the best I have seen reliably out of a stock shortblock 2v was about 450 WHP, and I defiantly do not want the shortblock spraying all over the ground. I feel that I am "doing myself some favors" by keeping the whp number around 25 WHP below the limit. A little insurance never hurts.

Edit: I am not trying to come on here and start shit, but your basic statement is:

You will have crap results running stage 2 N/a cams and FI. You will loose boost (or have to pulley up) and you will not make more power than the stock cams....

However, real world results have proven both wrong... And your answer is "the stars aligned". I dunno anything about stars effecting RWHP results, but I have only stated the facts as they happen. You tell me not to come on here without "factual data". What do I need to do, post the videos of the boost gauge and dyno sheets?

Edit #2: It is universally accepted that mustang dynos read signficantly lower than dynojet dynos. The mustang dyno in St louis has proven to dyno right around 10 percent lower than the 2 dynojets in st louis, at least fairly closely (10~ WHP). I dunno what else to say...

#12 10-19-2006, 12:05 PM

One last thing...

I am not saying that I would install a set of N/A cams with the specific intention of putting a blower on it. However, if you already have stage 2 n/a cams, they WILL work well with FI, so long as you do not try to make big numbers (what was ment by this was 500~+)

At this point and time, I cannot honestly say that a set of blower cams would make more power than the n/a cams that I have. The car is already close enough to the limit, espcially with no intercooler. I am in the process of installing a DIY intercooler (or will be soon) and I expect to make around 430-440 WHP (dynojet).

The next step after this is to replace the shortblock fuel system, and at the same time the cams (for a set of MPH custom blower cams). I have no doubt that at that point the blower cams will make signifcantly more power.

Your last sentence comes farily close to calling all out bs. Would you like the links to the streetfire vids?

Edit: here they are

Dyno vid, (no streetracing):

http://videos.streetfire.net/video/2...2d00aade84.htm

Boost gauge (shitty angle of the gauge, but I can always make another vid if you really need one):

http://videos.streetfire.net/video/C...1A9FB4A9A8.htm

UveLost · #13 10-19-2006, 12:09 PM

I dont mean to hijack the thread but does Nitrous fall into this same catagory? Would you use n/a cams or "blower" cams for a N20 application?

and by no means am i well versed in the physics of head air flow but what Kieth and green monster said about the overlap makes sence.. BUT on the other hand there are things that i have heard of that i wouldnt think would have worked but did.. maybe not the full potential that they could have.. but it still worked..

#14 10-19-2006, 12:14 PM

I had originally thought I was going with a H/C/I and nitrous setup, until I started to price out all the parts needed.

I believe people do have custom grinds availble for nitrous, and honestly I would not go with any "stage X" cam knowing that you can usually get a custom grind for basically the same price.

greenbird · #15 10-19-2006, 12:50 PM

Quote:

Originally Posted by UveLost

I dont mean to hijack the thread but does Nitrous fall into this same catagory? Would you use n/a cams or "blower" cams for a N20 application?

n2o likes a large split duration, and early exhaust events. If you had a race only vehicle, you would want an n2o specific cam. Since you probably don't, a custom NA/n2o cam would be a good compromise. You can have top NA performance and very good n2o performance out of one cam.

Sash · #16 10-19-2006, 01:10 PM

When I pick up my car from the shop I ask my tunner-motor builder about my N/A cams if they was going to work whit the blower or I have to change to blower cams,his respond was: This cams going to be just fine.

Sash · #17 10-19-2006, 01:13 PM

By the way 2000GT4.6 thanks for come here to answer the question........

CompOrngGT · #18 10-19-2006, 01:53 PM

Quote:

Originally Posted by Sash

When I pick up my car from the shop I ask my tunner-motor builder about my N/A cams if they was going to work whit the blower or I have to change to blower cams,his respond was: This cams going to be just fine.

Some "NA" cams, such as the Comp line, will work well NA or FI. Due to the higher l/s, there's less overlap. Someone correct me if that's wrong, but I believe it's true.

#19 10-19-2006, 01:59 PM

Simply put, the stage 2 n/a cams run JUST FINE. I do not have anything special done to the car, its not black magic.

Nobody is going to say that a stage 2 n/a is better than a FI spec cam, but its still better than the stocker, it hasn't killed any boost, and in my case I am literally leaving power on the table for the shortblocks sake.

If the shortblock could take it, I bet a powerpipe would make 1-2 PSI and 450~ with NO intercooler.

You don't have the perfect cam, but the perfect one isn't going to gain all that much on a FI cam. You can take the car to the limit of the shortblock with the N/A cam... Whats the difference?

99_Bluestanggt · #20 10-19-2006, 02:11 PM

So N/A cam on a blower car. Lose boost through the exhaust valve.

How about blower cam on a N/A car? Would he have been better off going with the blower cam over the N/A cam before he put the supercharger on? That way, you don't have to buy another set of cams for the blower.