I have so very little real insight on cams. What I'd like to have is a more genral, practical input on the whole idle quality vs power issue, and what makes good idle quality, ie: lobe separation?? That is my best guess, that relatively small amounts of lobe separation tend to improve idle quality, while getting away from that makes worse idle but is needed to take advantage of a more powerful cam design. But I'm just not sure. I am a little torn with how to improve my 455. OK, it's a 0.030" overbore with a set of smog heads, stock, no gasket matching, porting or decking of the block. 10:1 pistons, TA headers (I want to say 2 7/8" primary? I have to honestly say i have forgotten), standard stock type dual exhaust, 2", TA RV12 cam, which I realised a while ago was a mistake, I outsmarted myself, but I will say that the engine idles like a photograph and purrs, Edelbrock performer intake, Edelbrock 800 cfm AFB type carb, GS air induction, Poston street/strip HEI, R45TS plugs. I have TA roller Rockers waiting for me to stop being lazy, but right now I have the stock rockers. Bought the TA units mostly out of paranoia about the 1.6:1 ratio rockers that I could put in being weak, and a fair amount of gee-whiz, laced with the knowledge that I won't have to buy rockers again, ever. I run this engine at 13* initial. I had checked total with a timing mark I measured off, but like a genius, while touching up some engine paint I painted the mark over. I'd like to say my memory is picking up the number 34* total, but that was with my old HEI that had bad bushings and it needed to be advanced approx. 17* initial. the last time I tuned the engine it was pulling great vaccum at idle, but I fully understand that that is subjective to my locale. ANYway, I had full intentions of buying al. heads, but maybe not now, money is a bit tighter than I had hoped. A cam swap will satisfy my needs to muck about with the engine- I wish I had the extra cash to build another- and the cam swap might laso be what the doctot ordered to make some noticeable hp gains without the loss of too much idle quality. A Stage 1 cam is naturally my first choice of cam to look at...those numbers, hmmm.:laugh: Just what do they mean in a practical sense? I have heard there are much better choices readily available with small loss of idle quality. here are my goals/desires for a new cam: 1) mimimal loss of idle quality. I like my Buick engine being relatively powerful and yet tame. I like to open the hood while the engine's running and look at a steady engine in my car- it's just satisfaction that I don't need a killer cam to make some power 2) I don't need a cam that makes an incredible amount of power. I am not planning on making a street eliminator or drag strip star. I like to think that I have a realistic goal, and that is one that knowingly is sacrificing some power for idle quality 3) A cam that will present a noticeable gain in feel in regards to power, but not a jaw dropping, change my undies omigodthiscamrocks feel. A bit of extra oomph is what will tide me over till the cash is available for the heads. I think this is reasonable. In any case, reasonable or not, cam design is still a mysterious realm for me. it's one of the few things I do not have much of a working knowledge of on my car and I want to gain some, so lay it on me, Buick peoples:TU:
JW just did a bunch of talking about this on my link. Here it is: http://www.v8buick.com/showthread.php?s=&threadid=19737 Sounds like heads are the big limiting factor and anything with a lift over .500 is a waste. You will need a longer duration cam, but not so long that you start losing too much vacuum and can't run your accessories. Good luck. Phil
Thanks Phil. I read that and it was the main reason for my post. OK, I can see how .500 is the limit, and good news for me because I can't go higher:grin: but what exactly are the other numbers doing for me is what I need to know. I wnat a handle on the hows and whys. What I am curious about is: what's your engine idle like: rock-like, smooth, good, fair, poor, mexican jumping bean:laugh: ? I imagine you didn't have to give up all that much idle quality but what do I knowo No: Until I found this website I thought it was me and the half dozen or so Buick nuts who I'd talked to who knew how to make power out of anything but a Chevy. ~edit: I should have noted that I, too, installed the cam straight up in my engine. Lacking experience with cam degreeing, a cam wheel, or an adjustable keyway led me to trust the engineers who designed the stuff. Being by myself building the engine and needing the car back on the road to get to work, I stopped worrying about it and just put it in
I would call my idle good. The car idles at about 750 in park and 650 to 700 in gear. Anyone can tell that it does have a cam in it. It doesn't shake the car, much, but a little bit. I can still take my 2 and 4 year olds for a ride with the wife.
so that's 12.29 territory, eh?:TU: Hmmm, that's something to think about. I'll pop your cam into the old desktop dyno and see what's what. i don't trust the darn thing, but it's fun to mess with!
DesktopDyno and Drag2000 is exactly what I've been using. It has been accurate to within three HUNDREDTHS on all my combos and transformations. And you can share engines between the two programs. So build the exact engine you want, and then download it in the drag racing program into your car that you've setup and you should have a real good idea what she'll do. It even accounts for weather, type of tires, size of tires, tranny and torque converter, style of driving, etc. Really good stuff. Definitely worth the money, IMO. And not that I would encourage this, but once it's downloaded onto your computer, you don't need the disk any more to run it. Gee, I wonder if a friend would like to see how it works on his computer???? Now, you can't do any of the real fine tuning that I'm starting to do with my car, like jetting and playing with the timing (I don't think, anyhow), but that's what the dragstrip is for. I'm still hoping to get this oinker to crack into the 11's. Then I'll turn on the a/c and cruise home. Gotta love it.
Wow, I didn't think it was that accurate. I'll take a few minutes out after lunch and see what I'll see. It says I have 340 hp at 4000 rpm and 480 lb ft at 3000 rpm right now. With just the addition of a Stage 1 cam and the Stage 1 valves it says 403 hp at 4500 rpm and 504 lb ft at 3500. Very very close to the commonly accepted power from the combo at the flywheel. I'll have to figure out the airflow file for the al. heads and see what it does :laugh:
