Hi Patrick et al,

I'm thinking abut changing out my custom camshaft with another one.
When I modifed my engine last year I was looking for a way to make my car faster without losing any of the drivability.
Its a 2000 C5 with A4, LS1, homeported 243 w/ PAC 1518s, .040 Cometics, LS6 intake, ported TB, Vararam w/o MAF, SD Tune, 216/220 cam (.600/.606) 113 LSA actual specs, C6 Z06 exhaust manifolds, cats and H-Pipe, stock catback, built A4 w/ 2200 GM converter, 3.15 diff., 6350rpm shiftpoint

I have a underdrive pulley lying around ready for install and I was thinking if there was a cam available which would provide me almost the same low end torque but a bit more high end power that I could install at the same time.
Since its my daily driver I look specifically at fuel economy with rpms under and around 1800-2000 but would also like to have some more pull above 4500.

I specced the current cam by myself after reading alot and using some engine calculators. It was originally a 214/219 LSL/XFI cam on a 111LSA but came out of production as stated above.
I haven't been on the dyno with vehicle after the swap but my only trip to the track gave me a 12.7 @ 112mph on street tires with lots of tire spin. Not fast enough for the mods I think. Due to my current compression and the small cam I have the suspicion that I can't make full use of max timing (21-24deg gives best performance right now).

I have read in the past about your 223/227 torque cam which sounds great but I'm unsure if it will give me similar low end torque as the one I have now.
Also, based on my previous cam choice I was planning for LT headers, but due to stock appearance requirements I settled on the C6 Z06 manifolds, which are very nice but not quite like LTs.
So now I guess I would probably benefit from more exhaust duration, although the pipes are dual 3" up to the catback.

I would appreciate it if you could give some ideas and direction on where you would go.
Thanks
Alex

 

I'm no Pat G, but in this case since you going to absolutely keep the manifolds and not go headers, then all roads point directly to a CheatR cam from Thunder Racing. Great cam very easy to tune has -9.0 degrees of overlap and makes great low end power and pulls to 6400. The exhaust duration you asked for is also another reason why the CheatR cam would be good for you since it is 214/230 .629/.592 117 lsa. I think you could even keep the same stall in your car currently though a good PY3000 would work perfect. The AFR/TR CheatR cam package is on Pat G's page and makes 400rwhp with stock manifolds/y-pipe/dual dual exhaust.

 

No cam expert but with the manifolds and stock cat back I would think something closer to 10+ degrees on a traditional split would be better suited. With the "uncommon" setup you have I think you would benifit more from a custom cam than 90% of the "norm" people with LS6 intake, LT's and aftermarket cat back that get a custom cam.

 

Just for clarification regarding the exhaust manifolds.
I talk about the LS7/LS9 manifolds, cats and h-pipe. These parts support the 505hp of Z06 and the 638hp of the ZR1. There are four individual hydroformed tubes inside this manifold. From research in the C6 community, people are only 10 hp or less behind LT peak hp numbers, torque for the LTs though might be higher. But these are hands down some of the best manifolds/shorty headers available.

 

403 rwhp LS1 with stock exhaust manifolds and mild cam


If you haven't seen this thread yet, it could be a step in the right direction for you. Look at the VE's of the prescribed cam compared to your current one (apologies, as I guessed at your ICL).
Patrick is definitely the right person to comment here, but your exhaust valve opening may be too early, despite the efficiency of your manifolds. It makes sense that your other goals appear to have been reached, as the rest of your VE's look fairly close. You may not be getting all of the exhaust gases out of the cylinder at higher engine speeds.

 

Thanks for the replies and links so far.
I read about the new EPS cam lobes. What are the sizes they are available in and how would they compare to my LSL lobes on my cam?
For a new cam, I don't mind having a slight lope from the cam although I would like to retain emission compliance.
I'm also kinda unclear on the 218/230 example cam that was used in the link you posted.
What was the reason for the 115LSA +4 advance. How would a 112LSA +0 behave?
Thanks
Alex

 

The intake events would not change much, the 112* ICL retards them just one degree. On the other hand, you are advancing the exhaust timing 7 degrees from 119 to 112. That change alone pushes your overlap to 0 at .050 lift, to much for emissions compliance and the very max you would want with manifolds. I'll quote Pat here...
This is from another relevant thread - Maximum Overlap on F-Body Stock Manifolds

 

Thanks for the links to the manifolds threads.

Because the Z06 manifold are so much better than logs, you can afford to go with a little more overlap. In this case, I'd go 1 step bigger than the 218/230 and go 222/230 .597/.600" 114LSA +4 advance. This is with the EPS "endurance" lobes from Engine Power Systems. Strong power under the curve and it will rev to the moon. It will be ideal with your beehive springs.

 

Hi Patrick,
thanks for your comment. From my calculation I would end up with -2* overlap instead of -8* with my current cam. How much more lope would that mean (idle rpm 700) and would I fail emissions or would it be borderline? What exacty would fail for emission testing?
From a DCR standpoint I would only loose a very slight amount and end up at 8.4 instead of 8.5.
What I'm concerned about is the low rpm torque that I like so much. Right now I'm able to cleanly pull away from 900rpm in locked 3rd gear (~22mph). If the new cam could do that from 1000-1100 its OK, but if I need to be at 1500rpm that would not be good enough. I know these parameters are hugely affected by the tune but the cam finally dictates the drivability.
For the future I plan a ported FAST 78. Again, low rpm torque and fuel economy are important. Would the cam choice be the same?
Last question, what power difference would you expect from the 222/230 compared to my 216/220?
Thanks alot,
Alex

 

Another thought after thinking about came to my mind. If the proposed 222/230 cam is slightly too big for my application (emission/lack of low end), maybe a 220/228 LSA114 +4 (-4* overlap) or even a 218/226 LSA114+3 (-6* overlap) would be better.
How do you think about these alternatives and would they sacrifice a lot peak power?
Thanks
Alex

 

Alex,
You do not pull from 900 rpm in 3rd (looking for trq band at that level), you should downshift to 2nd.
The cam Patrick speced also has different lobes than what you have and the Ve's are spot on for your application.
Bottom line if you are looking for more, you cannot expect it to drive like the one you have, it will be slightly different.
The more agressive lobes, higher overlap of PG cam will net you more peak power and better undercurve than your 216/220.

Also -2* overlap will pass emmission sniffer with a "lean" tune. (which can be readjusted after test).

Mark

 

The 900 rpm in 3rd example was used only to show that my current cam gives very good low rpm torque, which I like. The question is how much of that torque will I sacrifice with the proposed cam by Patrick G. (222/230)?
Another option that I came up with is a LSL lobed 219/227 LSA114 +3 , -5 overlap. It will probably come out a bit larger in duration like most Comp Cams and slightly shorter in lift.
Unfortunately the EPS lobes only come as 226 and not 228.
I feel better if I err on the smaller side to retain low rpm drivability.
Would I be OK with my PAC 1518 springs?
Thanks
Alex