[85mclaren]

This question might have already been asked somewhere, but need your D series expertise on this....

I know I keep referring to the 5.0 on most of my posts and am sorry if that bores people, but it is what I have to compare my knowledge against these motors - as I do know they are different animals....

Question and comment is this ?

For the speed density car mustangs/capris (86-88) - we use to choose a cam that had a mild LSA (114) and a smaller duration with higher lift and/or use the old trick of replacing the 1.6 rockers with 1.7 rockers which gave us appox .030 more lift.This is turn gave the car less drivability and idle problems. Now I know what you all are probably thinking. We didn't have tuners for our speed density cars back then. Yes - that is correct, but we did find we did make pretty decent choices in doing this. We kept our low/mid range torque up while also extending upper rpm hp. Of course if any of you have ever been behind a pretty stout 5.0 - you know torque is not necessarily a major problem....;-) Since I have a feeling my rocker arm 'trick' is out of the question with my Z6 motor, I was looking at the crower turbo cam.

The turbo cams profile is as follows: Which it gave the LSA on these cams vs the stock as this IS an important factor in idling, etc, but OH WELL).

Advertised Duration Duration @ .050" Gross Lift w/ 1.6 int /1.8 ext
312 / 318 234 / 217 430 / 427

while the NA stage 2 cam is as follows:
319 / 310 235 / 223 432 / 436

Doesn't seem like a huge difference here. I don't pay much attention to advertised duration as much as the starting point of .050 duration is what matters to me and they seem pretty close. Seems to maybe favor the exhaust side a LITTLE more probably because the thought of the turbo. Lift also seems to favor the exhaust side also because of the same reason.

Was thinking this cam might actually perform better than the NA cam. Any one actually try this or have any dynos on this cam vs the other....?

Any comments are appreciated....
Jason

 

[BigTuna]

Buy the NA Stage 2 you wont be disapointed.

 

[88cr-rex]

They both can support enough to mess up some stuff . . . I don't see that it matters since they are on the same lsa.

looks like a case of marketing hype IMO . . .

 

[Orion]

Well paper is only paper, the lobe slope profiles cannot be read from duration / lift specs (unfortunately), they only give a rough guideline. That being said, there's only one way to find out...

Take Catcams cams for instance. They seem really, really mild on paper. But they have lobes that are flattened at the end, almost squared off even. In reality, a seemingly mild cam from them can give some of the sharper profiles out there a decent run for their money. To illustrate this, their Stage 1 cam for the A6 is in fact milder than the stock cam on paper, but I've seen a member on this board put down 155hp at the flywheel and more torque than a 2.0 VW Jetta with that cam.

So you really can't completely judge a cam by duration and lift specs. I think the turbo cam is probably better at making power on stock compression motors while the NA cam will benefit more from higher compression.

Also note that the specs are only for the Vtec lobes : the turbo cam might have completely different low-cam lobes to help spooling the turbo at lower rpm.

 

[EG5[KRT]]

i thought that turbo cams have less overlap because it doesnt need to scavenge the ports.. coz of the forced induction.. so therefore it can make more power.? ?

 

[BigTuna]

i thought that turbo cams have less overlap because it doesnt need to scavenge the ports.. coz of the forced induction.. so therefore it can make more power.? ?

That was the old method of thinking, now adays turbo guys love NA cams. It gives them the lift and duration for high RPM power.