Considering your 'hypothetical' discussion is based on building a trully stock looking stealth package... why not go with a GM casting CNC'ed head? This way your car will look stock under the hood, even to the trained eye...

 

Stock CNC head wont give the same power as the DART head.

The Darts are only 1200 bucks complete as well.

Discussion centers around making lots of power but having great (better than stock) average torque and HP through the whole curve. Fully emissions legal etc.

The contentious issue for me is EVO and its affect on torque production and also DCR's upper limit on 91 octane Some say 8.5 is the max, others go as high as 8.8 DCR.

It's not about tricking someone it's about maximizing average hp and tq while keeping stock manifolds/exhaust, a reasonable shiftpoint (~6000-6100rpm) and better than stock drivability.

 

Sorry for the sidetrack...

What EVO would you suggest for stock mani's and maximum torque production?

I want to maintain power well after peak.

 

I had a wife like that once. Gee, I miss her.

 

I want to know the same. I'd like the same shift point with the torque output but what do headers change as far as the EVO

 

hahaha!

 

With regards to DCR, 8.5 with 91 octane and 8.7 with 93/94, that is with a good tune.

On stock cubes 44>46 EVO means great low>midrange trq
47>50 good low>midrange put power range is shifting higher in rpms
above 50 is low trq in low>midrange output. Trq comes on later in rpms.

 

Prdator-Z,

Could we get a similar "rule of thumb" for overlap? Interval and affects on curve profiles? Application is LSx with full exhaust.

Ben T.

 

I thought Patrick had spec'd a very similar cam/combo in his 20k hit cam thread.?.?

 

There is no real "rule of thumb", it is relative to duration used, VE's, size of motor etc....
You cannot say 110 lsa or 20* overlap will make power there and not here.
The VE's and durations will dictate that.

 

almost ?

 

There are alot of very strong curves with the afr 205 - 224-228 cams. Since the Darts are cast 205's should be similiar. They wont idle as good enough for you plan i dont think. That new bad *** lift cam Patricks is ground on would be cool but use less duration or widen lsa perhaps to smooth out.

 

Comp XFI lobes

268/218
274/224

41' ABDC
48' BBDC
-7 overlap
8.58 SCR

114+2

 

6100 rpm peak
good midrange trq

I prefer 218/224 113+0
42>IVC=6200 rpm peak
45>EVO= more trq in midrange

 

is the XFI lobe what Pat's cam uses?

 

Comp LSK

 

ahh ok

 

Comp also makes a lobe that specs at 269 seat to seat, 220@.50, 145@.200, and .597 lift if you'd like to run a 4 degree spread instead of 6. (It's not listed in any catalog)

 

Those combos are setup with headers though.

I am using stock manifolds. Those cams are great with headers but I need to maintain -5 to -10 degrees overlap.

 

That is a nice cam. I was also looking at 220/220 113LSA 109-110ICL as well for use with stock heads and stock manifolds/catback