dsommer Posted November 7, 2001 Share Posted November 7, 2001 My biggest concern is the camshaft. I don't want this to be a super lumpy unstreetable set up with no vacuum for the brakes (been down that road before) My planned set up is a 350ci chevy 4 bolt mains Edelbrock Performer RPM intake Edelbrock Performer RPM heads with stronger springs for roller application, roller rocker arms 1.5 ratio Hyperutectic pistons 10:1 compression 30 over. Eagle bushed rods 73 Datsun 240Z (approx weigh 2500 lbs.) and will be equipped with either a Borg Warner T-5 or T-56 transmission Rear end gear ratio 3.90 CAM SPECS: Competition Cams P/N 12-769-8 Intake Exhaust Valve Adjustment 0.016 0.018 Gross Valve Lift 0.552 0.564 Duration At 0.015 Tappet Lift 268 274 Valve Timing At 0.015 Open Close Intake 28 60 Exhaust 71 23 These Specs Are For The Cam Installed At 106 Intake CL Intake Exhaust Duration At 0.05 230 236 Lobe Lift 0.368 0.376 Lobe Separation 110 Thanks ya'll David Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 7, 2001 Share Posted November 7, 2001 That cam has less duration than the 12-677-4 flat solid that Comp Cams recommended for my 327 and they said it would be streetable and have vacuum. I think it will be fine and lots of fun! Quote Link to comment Share on other sites More sharing options...
dsommer Posted November 7, 2001 Author Share Posted November 7, 2001 So what HP/Torque am I looking at? Maybe I should go with a little bit more duration cam? What I'm looking for is at least 420 HP, the reason that is my base line is the Edelbrock power package claims those numbers and I could get out cheaper going with a std hydraulic cam as opposed to a solid roller ds Quote Link to comment Share on other sites More sharing options...
John Scott Posted November 8, 2001 Share Posted November 8, 2001 Pete, if you have the time..could you run another??? 383 242/248, 570/576, 110. 10.7:1. AFR 195, victor Jr. 750 cfm. Love to see how it compares to the dyno up here when we test it this summer. JS Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 8, 2001 Share Posted November 8, 2001 No DD2K here at work - I'll run it tonight and post. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 8, 2001 Share Posted November 8, 2001 my computer says that comp cams grind will get you about 404 hp/381 ft lbs but looking through my notes I tryied a crane hydrolic roller # 109841 and with the same parts it gives you 417 hp and 445 ft lbs (thats 64 more ft lbs of torque and 13 more hp, a big gain!!!)BTW it has 234/242 dur@.050 .539/.558 lift and a 112 LSA so the idle should be simular to the comp grind Quote Link to comment Share on other sites More sharing options...
dsommer Posted November 8, 2001 Author Share Posted November 8, 2001 Grumpy, Can you run this for me? I'm kind of stuck with a solid roller because I already have the lifters. This is Comp Cams P/N 12-770-8 Gross Valve Lift 0.564 0.57 Duration At 0.015 Tappet Lift 274 280 Valve Timing At 0.015 Open Close Intake 31 63 Exhaust 74 26 These Specs Are For The Cam Installed At 106 Intake CL Intake Exhaust Duration At 0.05 236 242 Lobe Lift 0.376 0.38 Lobe Separation 110 Thanks again for your time. David Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 8, 2001 Share Posted November 8, 2001 dsommer sure be glad too, but with that much duration a dual plane intake is going to kill the higher rpm flow so Ill run it with both a performer rpm and a super victory intake/750 holley, to show you what I mean! performer= 395 hp/375 ft lbs super victory= 440 hp/370 ft lbs as you can see all that duration and the single plane intake hurt the low end torque but give it back in high rpm flow Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 8, 2001 Share Posted November 8, 2001 Sorry, I didn't get on the computer last night. But guys, grumpyvette's numbers are as good, if not better than DD2K - he's got some kind of home grown stuff to do a better job! Plus a whole lot more experience than I do, with the computer or building and tuning SBC's etc. IOW, you've got great estimates from him! (Sorry, I just had to try that new imagae Icon ) Quote Link to comment Share on other sites More sharing options...
dsommer Posted November 8, 2001 Author Share Posted November 8, 2001 Grumpyvette, Is there a grind in your library (Crane or other brand) similar to the hydraulic roller P/N 109841 for a SOLID ROLLER that will make the 417hp/445 or close to those numbers? I’m stuck with the RPM intake and roller lifters and want low speed driveability. I’m just trying to figure out what cam will give me the best all around performance. I don’t have to go with a Comp Cam, any solid roller is fine with me. Again thanks for your help on this. David Quote Link to comment Share on other sites More sharing options...
Tim240z Posted November 8, 2001 Share Posted November 8, 2001 Grumpyvette, What software are you using to pull these figures? Just curious, Thanks, Tim Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 8, 2001 Share Posted November 8, 2001 Tim240Z my son is a computer software programer so I had him combine DD-2000 an ENGINE ANYLIZER and DRAG STRIP PLUS and a few other programs for my personal use. dsommer yes if your willing to change to a super victor (EDELBROCK # 2925) intake and a 750 carb the CRANE solid roller # 118691 (250/258 @.050 dur .561/.561 lift on a 112 lsa ) will give you about 443 hp/440 ft lbs and the CRANE #118131 242/250 @.050 dur .580/.600 lift 0n 106 lsa will give you about 453hp/439 ft lbs (call crane for advise too 1-386-258-6174) Quote Link to comment Share on other sites More sharing options...
Guest needwaymorespeed Posted November 9, 2001 Share Posted November 9, 2001 Speaking about engine simulators,why is it that when I put in custom head flow #s into dd 2000 that unless I put in extremely large valve sizes I dont get a realt o life increse in horsepower?? For example I played around with the flow #s on afr 195 gave each lift parameter an extra 100 cfm of flow horsepower only change by 10 hp-when i stuck 2.300 intakes and some outrageously huge exhaust valve in then I got some horsepoer improvements like 100 hp. I think dd 2000 is missing some key points-a smaller valve that flows the same cfm as a larger valve is better in every way-higher velcity-same amount of cfm through a smaller hole- less valve shrouding less valve weight what gives is the program inaccurate-am i inputting info wrong or am I just out to lunch?? Curtis Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 9, 2001 Share Posted November 9, 2001 needwaymorespeed I dont think you have a good grasp on what the program measures and how it relates to airflow in the ports. first the ports in a given head have a cross sectional area that can only flow a certain amount at 28" of vacuum (the standard measureing flow)that area will always be about equal to the valves max flow because to make it much larger hurts flow velocity without increaseing that flow past the valve,(the the valves have a curtain area(lift x valve circumference) that max,s on flow at about .52 lift x the valve diameter because the curtain flow area of the valve reaches the same area as the hole the valve closes at that lift.now lets look at an example, lets look at an AIRFLOW RESEARCH 195cc head(about 280cfm at max lift)heads are measured at a steady flow with an open valve at a steady 28" of vacuum but heads are used in a 720 deg cycle of the 4 stroke engine this means that only about 250 degs of that 720 degs are actually available to flow air into the cylinders on a per port basis durring that 720 deg cycle and only about 72% of that 250 degs is meaningful flow numbers.a good way to judge possiable hp potential of a high performance head is to look at the ports max flow (280cfm with the AFR head) and multiply it by .257 x the number of cylinders(8)= max hp or 583hp in that case is the max possiable non-assisted hp available from that unmodifyied cylinder head on any engine with that cylinder head.now if you put unrealistic flow numbers into the data you get unrealistic answers (garbage in garbage out) so check your answers against that formula and if they are far off your data not the program useing it is WRONG! Quote Link to comment Share on other sites More sharing options...
Guest needwaymorespeed Posted November 9, 2001 Share Posted November 9, 2001 Grumpy I dont think its the info I think the program is confused. theres alot of dispute as to just how much horsepower is available from the cfm rating of the heads ie losses through the carb size and intake manifold.I think you loose 5-7% of youre heads cfm numbers from the intake manifold. If i understood you think the computer is rejecting my cfm numbers to valve ratio numbers due to port velocity?? You make a good point about valve size in relation to the smallest cross section area of youre port runner but if the smaller port and valve will flow the same cfm as a larger valve, port does this matter?? For example a cnc ported 195 comes out at 201cc and flows 279cfm at 28 inches-in slc anyways-with a 2.02 valve. A afr 210 cnc ported comes out at 222 cc and flows 291cfm with a 2.08 valve were talking only 12 cfm difference at a .700 lift opening.-now these were flown on a older superflow 300 in salt lake . I still think theres something up with my dd2000 another example is my bbc heads they flow 360 cfm at .700-the good intake port does-well when i put these inthe program with my 2.25 valves and 1.88 exhaust I get like 560 hp if I goto dd dynos rectangport canted valves" the ones included with the software" I get 760 hp when i look at the flows listed for these heads they are less than mine and also are listed in the program with 2.02 and 1.6 valves dd 2000 is hosed!! So is there a different way to input this data what am I missing Curtis Ps-Grumpyvette I love to read youre posts have read several from chevytalk and love having you on this site Thanks Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted November 9, 2001 Share Posted November 9, 2001 Hrm, very interesting Grumpy. I've always known that peak HP numbers like peak flow numbers didn't mean nearly as much as "area under the curve". Honestly and IMHO I think one of the reasons I've always found forced induction so attractive is that the motor is no longer having to struggle quite so hard to draw air past every intake restriction. Valve flow still matters but the pressure in the intake would seem to me to make much of the restrictions less important than the valve's flow. Hard to explain what I'm trying to say but it seems to me that air blown versus drawn would certainly seem to flow more easily past restrictions ahead of the valve. Forced induction seems to make greater sense to me as opposed to having to increase RPM to gain power. Nitrous is also attractive for those reasons, sprayed into the port it bypasses all or most of the restrictions and brings along it's own oxygen Valve flow ends up being most of the choke point vs the rest of the intake path. In a liquid form it would seem to be sort of condensed - liquid HP so to speak. I've never liked nitrous as much as compressed air though - too greedy if it can't find the fuel it wants. Starts to eat things like aluminum Anyway, I've always liked a milder motor with forced induction over a motor with a wild cam, lumpy idle, and higher rev requirements to get the job done. Heh, I think I just described the Buick GN as having the perfect motor Low revs, high boost, high HP... Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 9, 2001 Share Posted November 9, 2001 needwaymorespeed lets look at your big block example first, you say the program gives you 760 hp well lets check that against the checking formula for max potential hp first, you say those heads flow 360 cfm so lets take that number times .257 times 8, that equals (740hp)the program says (760hp) but it has a built in fudge factor to compensate for headers that help cylinder scavageing, so for most cases it matches,now if I read you right the AFR sbc heads flow 291 now if we run that through the formula we get 291 x .257 x 8 =598 hp you got 560hp with that flow. but the program also knows those valves are smaller and flow less so altho the heads are capable of 598hp the valves are not up to that level of flow so the program compensates and when you increase the valve size the program looks at the flow numbers, checks against the valve size, sees its possiable and raises the hp numbers. hey its just a guide its not totally infalliable. use the formula to check your results,its a good way of finding bad info! BLKMGK your correct once you place positive pressure behind the intake valve (supercharge) almost any hp can be reached! btw did you notice the relationship of that 720 deg cycle where about 72% of the 250 degs that the cam has the valve open is meaningful flow? well 72% of 250 degs is about 180 degs and .257 x 720 degs is about 180 degs, so what that formula is doing is ruffly figureing cylinder flow!and you should recognize that 180 degs remember (720 degree repetitive cylcle)intake,compression,power,exhaust,,,720 divided by 4 =180 degs. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted November 9, 2001 Share Posted November 9, 2001 Hrm, now I want to run out and figure out what my heads flow! This is neat stuff, thanks for the education Quote Link to comment Share on other sites More sharing options...
Guest needwaymorespeed Posted November 9, 2001 Share Posted November 9, 2001 Grumpyvette Thata the problem the valves are also capable of that 291 cfm figure because that is how they were flown-with the valves in the head-see my dilemna-I get 291 cfm with the small valves-the program shouldnt care on the valve size if you have raw flow numbers inputeed-because you have real life info-I dont know why the afr's flow that well I just know that they do and it's irritating that this program wont accept my real world numbers without me tricking it with inputting the larger valve sizes! I still think that the more flow you can get with the smallest valves is the best scenario my reasons for this are 1-less valve weight too control 2-less valve shrouding in the combustion chamber and cylinder walls 3-higher velocity due to the smaller opening Oh well I just think my dd200 is confused if you reread my post above youll see that dd 2000 makes less hp with my bb chevy heads vs's the bigblock chevy canted heads that they have in cluded with the program-and yet my heads have better flow #s then there default heds-plus there default heads show a 2.02,1.6 valve sitip-oop someone wasa sleeping at motion industries that day!- I suppose that im just expecting too much from a 50.00 program-guess thats why you have youre custom program-sounds very nice! Grumpyvettte just curious what part of the country you live in? would love too meet up with you and benchrace. later Curtis Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 9, 2001 Share Posted November 9, 2001 needwaymorespeed I live in LOXAHATCHEE FLA thats a town about 20 miles west of palm beach or if you have a map it half way between the lake and the atlantic ocean and yes your correct DD-2000 has a few flaws Quote Link to comment Share on other sites More sharing options...
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