98 k1500 stock cam?

[slowburb]

Do it right once. Replace the both of them together, cam/valvetrain & fuel system. Then get it tuned.

 

[Tinbender59]

go with a 411 ecu for better tunability

 

[silverado13]

i still dont think that the spider system will be able to keep up with it even with the 411

 

[6789olds]

lt4 hot cam, new spider , tune will get you 370-380 hp add 1.6 rr and 380-390 hp and your fuel system will keep up . its a provin set up . so is the zz4 cam and tune gets about 340-350 hp

 

[Aloicious]

alright thanks, how big of a cam can the vortec fuel system handle, ive seen people throw random numbers around but i want to know a definite answer because i want to add a cam but dont want to over welm my spider poppet system

i still dont think that the spider system will be able to keep up with it even with the 411

just swapping a cam on a stock engine won't come close to exceeding the poppets' limit. the poppets can handle up to around 400 FWHP at their absolute max (and that is not wise to run them that high, though I know at least one person who does successfully). stock L31 engines are rated at 255FWHP, there is no way only swapping a cam will overwhelm them at all.

and just to clarify, the 411 doesn't change how much power the poppets can handle, it will increase the ability to tune the vehicle, and get more control of various factors like drivability, but a tune cannot alter how much fuel an injector can flow.

lt4 hot cam, new spider , tune will get you 370-380 hp add 1.6 rr and 380-390 hp and your fuel system will keep up . its a provin set up . so is the zz4 cam and tune gets about 340-350 hp

all these numbers are erroneous if you're talking about a stock engine to start with. on a stock L31 that specs at 255hp, just changing to an LT4 Hotcam/poppets/tune will NOT give you a 115hp gain. on a 383 with head work and other mods, you MIGHT be able to reach those numbers, but absolutely not a stock engine. and if you were running an engine with close to 400hp, then your poppets would be struggling, ALOT. at that point you'd be hitting 80% duty cycle (the max recommended injector duty cycle) VERY easily and unless you hit the poppet jackpot and just happened to get ones that flow a little more than most (it does happen, the tolerance on these poppets is fairly large), even then you'd be going static, and even exceeding 100% Duty cycle, which is bad news.

typically on a stock motor, with a cam swap and proper tuning, you should expect to get anywhere from ~20-60 hp all depending on the cam selected and quality of the tune, as well as environmental factors too. you might be able to get a little bit more, but not typically, and definitely not from an LT4 or ZZ4 cam. the poppets and a tune will be able to handle that. however if you're modified to the point where you will be exceeding 325-350hp, then you need to look at other fueling options like the marine intake or something that can use higher flowing injectors. you do not want to run your injectors much over 80% duty cycle because it destroys the linear functionality and injector predictability and you can get all sorts of problems.

 

[silverado13]

that clears stuff up a little but ive heard of all these numbers about cams about whats the limit for size, like i heard anthing under .500/.500, what specs is your cam?

 

[Aloicious]

on stock vortec heads, anything over a stock cam you'll want/need to at least change out the valve springs and retainers for clearance.

here are some cam specs for popular GM cams, mine is a ZZ4

Stock L31 cam:
Intake lift- .414"
Exhaust Lift- .428"
Intake duration @.050"- 191°
Exhaust Duration @ .050" - 196°
Lobe Separation- 111°

ZZ4 cam
Duration @ 0.050" Lift: 208°/221°
Lift: .474"/.510"
Lobe Separation: 112

LT4 hotcam:
Valve Lift:
@ 1.5 ratio 0.492”/0.492”
@ 1.6 ratio 0.525"/0.525"
Duration @0.050 cam lift 210°/228°
Lobe Separation 112°

 

[Tinbender59]

its all about lifters, the flat tappet lifters and flat bottomed and just sit flat on the cam lobe, the rollers have a wheel that sits on the cam lobe and rolls as the cam turns. you want to match the what kind of lifter the cam was ground for with what you're using, otherwise you might have problems, heres a picture to illustrate why you don't want to use a flat tappet lifter on a roller cam:

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this answer is nicely done !!!!!!! keep up the good work

 

[silverado13]

whats the difference between mechined and hydraulic roller tappet?

 

[RHamill]

Does the Hydraulic roller have a different idle than the flat tappet cam? Slower? Faster? Lopey-er?