labrat Posted June 11, 2002 Share Posted June 11, 2002 Hey guys, just ran my el-cheapo combo on Dyno2000 and here's what it says... RPM HP (fly) Torque (fly) 2000 152 400 2500 195 410 3000 240 420 3500 289 434 4000 335 439 4500 374 436 5000 396 416 5500 402 385 6000 385 337 I picked this combo because 1.) cheap parts. This is with unmodified vortec heads and flat top pistons. 2.)flat torque curve up to 5000rpm. drops off a little by 5500, and then dies around 6000. My question is, can i run this combo reliably at low to mid rpms with stock internals, or will i need forged pistons, rods, and crank to keep this thing from going grenade on me? I won't be twisting it over 5500, but i don't want to be stupid cheap, either. How long would stock flat tops, rods and crank last in this combo? Just fishing for opinions... thanks Bill Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 11, 2002 Share Posted June 11, 2002 I'd think a stock cast crank, stock forged or PM rods, and cast or better yet hypereutectic cast pistons would be fine. Keep it out of detonation and below 6500 and I'd think those parts (if magnafluxed, prepped and assembled correctly) would live fine at those power levels. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted June 11, 2002 Share Posted June 11, 2002 heres a fairly simple test (1) is the piston speed over 4000fpm (48000/stroke x 2 = 4000fpm piston speed RPM MAX LIMIT which should only be reached for an instant before shifting) (2) is the compression ratio 11:1 or greater (3)are you going to use over a 100hp nitrous shot? (4)are you going to run the crap out of the car every chance you get and/or not use a ignition rpm limiter? (5) will you exceed 6300rpm where valve float, especially hydrolic lifter valve float is likely? (6) do you enjoy long smokey burn outs and catching rubber in each gear change answer yes to one and you probably could use forged parts answer yes to two or more and you NEED forged parts labrat keep the rpms at 5500rpm or less and you should get years of use out of that combo. Quote Link to comment Share on other sites More sharing options...
labrat Posted June 11, 2002 Author Share Posted June 11, 2002 Well, the car is going to be a daily driver, so it's not going to see THAT hard of use. I might get on it a little, but i won't be draggin to hard. Just hurting some ricer feelings here in Austin on the highway... Thanks for the advice, i'm trying to keep fairly cheep on this combo, but I didn't wanna get stupid with it. I thought the low revs would be key in helping out the longevity of the internals, but I wanted to be sure. I'll just be sure to set the rev limiter low (around 5800) just to be on the safe side. Thanks a million, fellows! I love to take advantage of the tremendous amount of experience on this board... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 11, 2002 Share Posted June 11, 2002 Might I inquire what cam your using, those are nice numbers, 439 ft/lbs at 4000, I like that alot. Thanks. Oh yeah, as usual Grump, you waste no words, thats a great test for forged parts. Regards, Lone Quote Link to comment Share on other sites More sharing options...
labrat Posted June 12, 2002 Author Share Posted June 12, 2002 That was an comp cams Xtreme Roller 270 (270/276 advertised with .496/502 lift) , just figured out it would be a little too much lift for the heads though, now looking at XE 262 which shows about 405ft/lbs@4000. Mebbe just cut the valve guides, though... Quote Link to comment Share on other sites More sharing options...
labrat Posted June 12, 2002 Author Share Posted June 12, 2002 That was an comp cams Xtreme Roller 270 (270/276 advertised with .496/502 lift) , just figured out it would be a little too much lift for the heads though, now looking at XE 262 which shows about 405ft/lbs@4000. Mebbe just cut the valve guides, though... Quote Link to comment Share on other sites More sharing options...
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