[spankenstein]

http://www.focaljet.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=010070;p=1

That is the old thread that sparked this experiment for historical reference.

Earlier this year I bought and installed a set of Crower stage II cams. I have been using Street Dyno to do a pseudo dyno and see how my changes are affecting my car.

With the crowers I made [email protected] and [email protected]:

I swapped in the stock exhaust cam leaving the crower intake cam and got [email protected] and [email protected]:

Here is an overlay:

I as expecting to regain some torque with the stock exhaust cam especially considering that in stock form the Focus Zetec makes 5 more lbf than hp at the crank. I was definitely NOT expecting more hp 8O

Modifications:

</font><ul type="square">[*]<font size="2" face="Verdana, Arial">Iceman intake and K&N filter
Ported throttle body
Crower stage II cams (noted when replaced with stock)
Esslinger UDP
SHM Evo exhaust with center resonator removed (2.5")
Small breather filter on PCV valve</font>[/list]<font size="2" face="Verdana, Arial">Cam grind specs:
</font><blockquote><font size="1" face="Verdana, Arial">code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Cam | Duration | Duration at .050" | Lift
------------------------------------------------------
Stock Exhaust | 286 | 205 | .352
Crower Exhaust | 276 | 228 | .374
Crower Intake | 271 | 220 | .374 </pre><hr /></blockquote><font size="2" face="Verdana, Arial">

 

[spankenstein]

Wow, a whole day and not a single comment on making nearly 10 more whp with a stock part over an aftermarket?

 

[CharlesWA]

It is interesting. I know way back when Esslinger came out with an intake cam but said they couldn't get any gains out of an exhaust came (at least not without head work and such).

I'm completely out of the loop as to what "Street Dyno" is. I'm guessing it's software? Is it downloadable and free or comercial or what?

 

[KicknZX3]

i'm impressed but i wanna see it on a dynojet...even though i'm kinda in awe

 

[teamDFL]

I am not sure how sophisticated Street Dyno is, but there is a lot to cam that cannot be know by just reading the specs that you provide. Still, it is interesting food for thought. Perhaps the best thing to do would be to see how closely the modelled Stage II dyno is to an actual one. Since Crower II's are everywhere, this shouldn't be so hard.

 

[spankenstein]

The problem with doing it on a Dyno thus far is that it costs a lot of $$$

http://www.tweecer.com/StreetDyno is the link. Basically, you record your spark and based on weight, gearing, etc it uses the time that it takes to accelerate the engine can be calculated to horsepower. I started using it on the reccomendation of someone who ahd compared it to a dyno jet and was consistently within 1-3 hp of it. I'm not putting these up as true numbers, but the curves in relation to each other are accurate. In addition to that I have been within 1-2 hp every time I've used it with no changes to the vehicle.

I will be dyno tuning in february, I was hoping to use this to pick which cam combo I would start with when adjusting the timing, I'm still undecided.

[ 12-17-2002, 09:06 PM: Message edited by: spankenstein ]

 

[Bimmerman9]

if street dyno is anything like desktop dyno i believe it . i have seen proof when i went to uti with our 350's that we build there ver close withing 2-3 hp

 

[Shiva Chaos]

i'd partake in this experiment if only i didn't want to put my old exhaust cam back in.

 

[spankenstein]

I'm not sure about desktop dyno but this uses a tach signal from either the coil or and inductive pickup.

 

[Paparoach]

Wow this makes me rethink cams

 

[redneckZX3]

I did that a while ago but havent had time to get to a dyno. at least now i kind of know what i am going to get out of the mix. thanks for posting your results.

geoff

 

[FocusBoy]

Paparoach - If you don't want to rethink camS, then think CAM. Know what I mean......? You know where to find me.

 

[spankenstein]

FocusBoy, are you able to get ONE cam from a set, and/or a mix of the profiles that Crower has?

 

[FocusBoy]

Yes to both of those questions.....

 

[Bimmerman9]

has anyone else tried this lately

 

[Travis]

basically A larger exhaust cam gives you more topend and midrange at the expense of low end torque. in this application the exhaust cam isnt near big enough to keep up.. you will see about a 7-9 percent loss in horsepower up top and a decent increase in sub 3000 rpm torque. I dont think the trade is big enough to warrant only buying 1 cam. Go with 2 its worth it.

 

[Travis]

Reading over that information that program doesnt take into account the flow rates of teh zetec head appropriatly. It cant because that just doesnt make sense. The exh/int ratio is about 80% with both crowers and 70 percent with just the intake cam. 70 percent is not good for maximum power.. Its not even really good for torque production.

 

[spankenstein]

I don't think you guys understand that it has nothign to do with calculating what's in the engine. It works by using how fast you accelerate. It records a tach signal and based on how quickly the time between the signals shrink it uses the informatino about your car (weight, cd, frontal area, gear ratios, etc) to figure power. This isn't that desk dyno program where you input engine specs and it tells you what the engine should run.

Please, before making more comments on my method look at the resources that I have already put up. The software is available at http://www.tweecer.com/StreetDyno/

I put the stock cam in expecting a loss in horsepower in the upper RPMS in trade for more power from 3k on. My problm was that it didn't feel like it had any oomph below 4500 RPM. I really would prefer the power curve start at 3-3.5k and hold steady until about 6k. That would be the most useful for me for autocrossing. In this configuration the car really takes off about 4.5k it's actually a very dramatic change.

 

[Travis]

Well if your using time based analysis and thats what your getting there is something crazy brewing in the focus`s engine because it is completely contradictory to my calculations.

 

[spankenstein]

What is the difference in valve size and flow rates on the intake and exhaust in the zetec head. I know that the "optimal" flow of exhaust is 80% the flow of the intake side.

I really didn't think this would be much of a combo when I did it but it turned out differently than expected. The engine just completely "wakes up" at 4500 and screams to redline from there. Not only do these graphs show it but in relation to other cars it's quite and improvement on the topend.

I'm getting ready to get cam gears and tune them on a dyno and was hoping to use this to decide which cam combination to start with, now I don't really know.

It would be fun to play with and engine modeling program to see what the cams would theoretically do to power.