Am I asking for trouble?
Am I asking for trouble?
Am I asking for trouble by building this engine to these specs? Pleas don't be shy I'm looking for as much info and opinions as I can get. I'm currently building a 383 to these specs, the calculated static comp is 10.75:1 and the dynaic comp is 7.9:1. The rotating assy is an eagle rotating assy, professionaly ported gm 186 double hump heads, and stealthram efi intake run my a converted 93 gm tbi computer. Any body running anything like this? Is this too much static comp? Is this too much or not enough Dynaic comp? Any advice? Anything i should be weary about?
Member
Joined: Feb 2010
Posts: 162
Likes: 1
From: savannah, ga
Car: 91 chevy camaro
Engine: 383
Transmission: 700r4 built with corvette servo
Axle/Gears: posi 3:73
Re: Am I asking for trouble?
Am I asking for trouble by building this engine to these specs? Pleas don't be shy I'm looking for as much info and opinions as I can get. I'm currently building a 383 to these specs, the calculated static comp is 10.75:1 and the dynaic comp is 7.9:1. The rotating assy is an eagle rotating assy, professionaly ported gm 186 double hump heads, and stealthram efi intake run my a converted 93 gm tbi computer. Any body running anything like this? Is this too much static comp? Is this too much or not enough Dynaic comp? Any advice? Anything i should be weary about?
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: Am I asking for trouble?
Some DCR calculators are pessimistic. What is the spec on your cam card for the intake closing?
Re: Am I asking for trouble?
Sorry it took me so long to reply, but I've been extremely busy with porting my heads, building a tranny for a friend, work among other things, but here's my specs for my engine and my dc was wrong before. Using the calculator on silvolite-kb website, it gave me 10.75:1 static and 8.53:1 Dyn. My engine specs are 4.030" bore, 3.75" stroke, 5.7" rod, 4.10" bore .015" head gasket, .020" deck clearance, and 68cc heads (after deshrouding). The cam grind is a CompCams 12-671-4, it's 276/283 adv dur, .468"/.462" lift, 112deg lca, IVO 30, IVC 66, EVO 78, EVC 26
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: Am I asking for trouble?
Wow, you're really pushing your luck with that one. Your intake closing at 0.050" is 42.5* abdc. It'll have plenty of dynamic compression. I suggest you swap in some ROL 0.025" head gaskets, retard the cam 4 degrees, and use premium and octane booster until you get the tuning dialed in, and then carry more in case it doesn't like premium the first time you try it without the octane booster.
For the rpm that combo should pull, 0.045" quench would be far safer than 0.035", plus it'll drop your static to about 10.52:1.
For the rpm that combo should pull, 0.045" quench would be far safer than 0.035", plus it'll drop your static to about 10.52:1.
Re: Am I asking for trouble?
How bout the same specs as before with this cam grind? It's 306/306 adv 113lca IVO 40, IVC 86, EVO 88, EVC 38 .447"/.447" Would this be better for my combo? I'm new to this dynamic comp stuff so please help me to understand it. thanks,
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: Am I asking for trouble?
Why do you keep choosing lame old cams? Something modern could offer you another 50 horses.
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