Mr_Efficiency Posted January 18, 2008 Report Share Posted January 18, 2008 I was looking around at the factory specs and found that the HO 2.8 in the fiero's used a better cam than the regular 2.8/3.1 and its also the same cam used in the 3.4 that came in the camaro/firebirds. anyone know anything about this cam? is it much better than the 2.8/3.1 cam? anyone running it? thanks Quote Link to comment Share on other sites More sharing options...
Andrew Posted January 18, 2008 Report Share Posted January 18, 2008 i have no idea the specs on that cam, but i do know that there are a few aftermarket cams available for the 2.8/3.1 http://store.summitracing.com/egnsearch.asp?N=700+4294925232+4294924497+4294887637+4294908396+115+4294908216 look at that Crane Powermax. Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 18, 2008 Report Share Posted January 18, 2008 I was looking around at the factory specs and found that the HO 2.8 in the fiero's used a better cam than the regular 2.8/3.1 and its also the same cam used in the 3.4 that came in the camaro/firebirds. anyone know anything about this cam? is it much better than the 2.8/3.1 cam? anyone running it? thanks Not sure of the specs, but IIRC, the gen 2 60*V6 uses roller lifters, but I know the gen 1 2.8 used flat tappett lifters. If that is the case, then the cam wouldn't work, as far as I know. If I'm wrong about this though, then just ignore the post Either way, I'd have to go look through my Fiero enthusiast book to find the specs... I'll post them when I get home this evening... Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 19, 2008 Report Share Posted January 19, 2008 Ok, so my Fiero book didn't list all the specs, but after a little digging this is what I've found. I'm not 100% sure on these specs, but they look right as far as I can tell... Duration at .50= Intake-196 exhaust-203 Max lobe lift at .50= intake-.263 exhaut-.273 Lobe seperation=109 Quote Link to comment Share on other sites More sharing options...
gp90se Posted January 19, 2008 Report Share Posted January 19, 2008 is thats right, that would be smaller then a 3.1's stock cam iirc Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 19, 2008 Report Share Posted January 19, 2008 I'm double checking those numbers, so we'll see... Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 21, 2008 Report Share Posted January 21, 2008 Ok, so my Fiero book didn't list all the specs, but after a little digging this is what I've found. I'm not 100% sure on these specs, but they look right as far as I can tell... Duration at .50= Intake-196 exhaust-203 Max lobe lift at .50= intake-.263 exhaut-.273 Lobe seperation=109 If that's right, then the cam is the same as the Gen II 3.1 liter(.2626 intake/.273 exhaust...the intake lift above is just rounded). Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 21, 2008 Report Share Posted January 21, 2008 Ok I got this from one of the guys over on PFF: Stock 2.8L Cam Lobe Lift: Intake = .2626" Overall lift with 1.5 ratio rocker arms = .3939" Exhaust = .2732" Overall with 1.5 ratio rocker arms = .4098" Install valve spring height = 1.575" BTDC = -14.0 ABDC = 30.0 BBDC = 27.5 ATDC = -4.5 It is a flat-tappet, You cannot use roller lifters. Quote Link to comment Share on other sites More sharing options...
Mr_Efficiency Posted January 21, 2008 Author Report Share Posted January 21, 2008 Just out of curiosity, what would the final ratio or whatever be on a stock cam with a 1.6 ratio rocker? I'm clueless on figuring that stuff out, lol thanks Quote Link to comment Share on other sites More sharing options...
spiderw31 Posted January 21, 2008 Report Share Posted January 21, 2008 Just out of curiosity, what would the final ratio or whatever be on a stock cam with a 1.6 ratio rocker? I'm clueless on figuring that stuff out, lol thanks The total lift would be .420 on the intake, and .437 on the exhaust. Just FYI, to calculate the total lift, you multiply the lobe lift by the rocker ratio. Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 22, 2008 Report Share Posted January 22, 2008 The total lift would be .420 on the intake, and .437 on the exhaust. Just FYI, to calculate the total lift, you multiply the lobe lift by the rocker ratio. ^^^What he said. I run the 94-95 1.6 ratio rockers in my TGP & SE. In my NA engine, there seems to be a little difference in highway throttle response, but I could be imagining things. Desktop dyno estimates were somewhere around 2hp when going from the stock to 1.6 ratio. Quote Link to comment Share on other sites More sharing options...
Mr_Efficiency Posted January 22, 2008 Author Report Share Posted January 22, 2008 thanks for the info guys. I have a set of 1.6 roller rockers but i'm going to find a set of 1.6 non roller so i can use my stock pushrods, I dont see it worth the hassle of custom length pushrods to run the rollers just to gain maybe 2 hp. plus its just cheaper to stick with non roller cause its all GM parts nothing aftermarket. Quote Link to comment Share on other sites More sharing options...
gp90se Posted January 22, 2008 Report Share Posted January 22, 2008 big benefit of roller rockers is less friction which improves horsepower, mpg and allows the engine to rev higher. I dont know how much of a difference you will see, but there is a difference between roller and non Quote Link to comment Share on other sites More sharing options...
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