Threw a rod.... Time for 383?
07-30-2011, 11:54 AM
#1
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Threw a rod.... Time for 383? I've got a 95 m6 Z28. 3.73 gears, short throw, cold air intake and exhaust. I just recently threw a rod so I know it's finally time for a rebuild. I've wanted to bore it out .30 and stroke it to a 383. Because I think im going to procharge or twin turbo it in a few years I know I need fully forged internals. The problem that I'm having is what compression ratio I should aim for. I had a friend tell me go 8:1 and just spray it until I get my power adder. What do you think?
07-30-2011, 12:11 PM
#2
You can build an 8:1 motor and spray it, but it will still be down on power compared to a 12:1 motor with the juice. I say start with big compression and spray....its a lot easier to get big numbers quickly. And if nothing else you have a really fun street car. Driving around everyday on an 8:1 will feel like a v6 without boost.
07-30-2011, 02:46 PM
#4
8:1 is ridiculously low even for a boosted LT1. For boost on an LT1 you want more like 9.0-9.5:1. To put it in perspective that is still 2 plus full points lower than an NA built LT1 would be.
Generally trying to build dual purpose is going to leave both compromised, you might consider going slightly low on compression with milled stock ported heads now and then when you add the boost you could do a Trickflow 64cc chamber head to lower compression.
If you started with a -16cc piston and ported stock heads cut to 53cc and a .039 gasket you could have it up around 11.1 for NA use and then a 64cc head later would drop it to like 9.9
Going to spend a lot of extra coin doing it in stages like that though.
IMO, throw a junkyard engine at it while you build what you want, maybe go ahead and buy the heads you want and use them on the junkyard engine.
Generally trying to build dual purpose is going to leave both compromised, you might consider going slightly low on compression with milled stock ported heads now and then when you add the boost you could do a Trickflow 64cc chamber head to lower compression.
If you started with a -16cc piston and ported stock heads cut to 53cc and a .039 gasket you could have it up around 11.1 for NA use and then a 64cc head later would drop it to like 9.9
Going to spend a lot of extra coin doing it in stages like that though.
IMO, throw a junkyard engine at it while you build what you want, maybe go ahead and buy the heads you want and use them on the junkyard engine.
08-02-2011, 04:28 PM
#5
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How many pounds of boost could i run on 9-9.5:1? I guess my main problem is that all my friends have turbo cars running on like 20lbs... Didn't want to waste my time boosting if i could only run like 4-6lbs...
08-02-2011, 06:16 PM
#7
TECH Apprentice
IMO building a motor with future plans for boost usually produces a disaster as far as performance goes. Focus on one and only one, also from what i've seen the high compression AI and LE 355's run much better than the backyard home ported 383's and or cars with blowers just bolted on em. Just my opinion.
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08-03-2011, 07:10 AM
#8
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@RamAir95TA yea, you're right... srt4's and integras...
@pro94lt I'm going to get it professionally built, I just wasn't sure about what i wanted them to build... And you've got a z28 m6 procharged... That's what I was going for, just not sure about how to do it. I've been in a mustang with 500 to the wheels and that's what i want, but i don't think i could do that off of straight motor.
@pro94lt I'm going to get it professionally built, I just wasn't sure about what i wanted them to build... And you've got a z28 m6 procharged... That's what I was going for, just not sure about how to do it. I've been in a mustang with 500 to the wheels and that's what i want, but i don't think i could do that off of straight motor.
08-03-2011, 08:55 AM
#9
8:1 is ridiculously low even for a boosted LT1. For boost on an LT1 you want more like 9.0-9.5:1. To put it in perspective that is still 2 plus full points lower than an NA built LT1 would be.
Generally trying to build dual purpose is going to leave both compromised, you might consider going slightly low on compression with milled stock ported heads now and then when you add the boost you could do a Trickflow 64cc chamber head to lower compression.
If you started with a -16cc piston and ported stock heads cut to 53cc and a .039 gasket you could have it up around 11.1 for NA use and then a 64cc head later would drop it to like 9.9
Going to spend a lot of extra coin doing it in stages like that though.
IMO, throw a junkyard engine at it while you build what you want, maybe go ahead and buy the heads you want and use them on the junkyard engine.
Generally trying to build dual purpose is going to leave both compromised, you might consider going slightly low on compression with milled stock ported heads now and then when you add the boost you could do a Trickflow 64cc chamber head to lower compression.
If you started with a -16cc piston and ported stock heads cut to 53cc and a .039 gasket you could have it up around 11.1 for NA use and then a 64cc head later would drop it to like 9.9
Going to spend a lot of extra coin doing it in stages like that though.
IMO, throw a junkyard engine at it while you build what you want, maybe go ahead and buy the heads you want and use them on the junkyard engine.
08-03-2011, 11:27 AM
#10
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@96capricemgr I guess that does make sense... And then I can save money bc i won't have to keep changing stuff... I already knew about the trickflow heads (thought they were 62cc though)... What size cam should i go with?
