How much boost and hp can a 98 3100 handle

[joshua52mcclain]

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[Guest]

Do yourself a favour and grab a 3.4 bottom end (from an F-body) and use the entire 3500 top end. This gets you the best flowing conventional pushrod top end, along with OEM provisions for the crank trigger that will be needed for the DIS system.

The 2.8 block can be used, but it's more work, due to needing an external crank trigger, and you're limiting the over displacement and narrows down your head choices. I used a 2.8 block for one of my hybrids years ago, simply because I couldn't find an affordable 3.4 block at the time. We're talking back in 2002 or 2003, so they were still relatively new at the time.

[fasteddi]

Do yourself a favour and grab a 3.4 bottom end (from an F-body) and use the entire 3500 top end. This gets you the best flowing conventional pushrod top end, along with OEM provisions for the crank trigger that will be needed for the DIS system.

The 2.8 block can be used, but it's more work, due to needing an external crank trigger, and you're limiting the over displacement and narrows down your head choices. I used a 2.8 block for one of my hybrids years ago, simply because I couldn't find an affordable 3.4 block at the time. We're talking back in 2002 or 2003, so they were still relatively new at the time.

Definilty what he said. If i wouldnt of had 2 3.1L engines already at the time i would have used a 3.4L and did a 3500 top end on my build.

[joshua52mcclain]

Ok I got you I was told the 2.8s stoke is 3" and the 3.1/4/5 are like 3.3" or something like that and for a turbo build the shorter stoke would be more reliable (for stock cranks) and handle more boost is this true? And would I be able to run 3.5 crank and rods in a 3.4 block because my understanding is the 3.5s are stronger

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[fasteddi]

Well a 3.1L is a stroked 2.8L. A 3.4L is a bored out 3.1L. So the stroke on a 3.1L and 3.4L should be the same. As for the 3500 im not sure as i never really messed with them. I have a 3.1L and last weekend I ran 4 passes all in the 11.60s at 119Mph on a stock crank and rods. Now it may be a freak car but if the tune is dead on you can obvously handle a ton of HP and Tq. For some reason i think that the 3900s had forged rods or a forged crank? On the non vvt ones? But the raven will know best over me.

[Guest]

The 85.5+ cranks are not as weak as people would have you believe. I think I've seen a total of 2 broken allegedly from too much power, but I think it was mor abuse than power because other people have made more power than the two broken crank owners claimed to have made.

Also 660s have forged rods.

The 3500 (LX9) has a steel crank, I want to say forged, but I think it was more likely cast steel. Earlier cranks were cast iron. I'm not entirely sure what the LZ engines (3500 and 3900 with VVT) have but I believe they are a similar material to the LX9.

[robertisaar]

GM says gen4 cranks are forged steel.
GM says the gen3.5 3500 cranks are cast iron or forged steel.

[fasteddi]

Im assuming that 2.8 3.1L 3.4L rwd gen 1 cranks are all cast?

[joshua52mcclain]

Ok well literally just got her in the driveway now ill truly know what im working with cuz I might be wrong on the year

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[joshua52mcclain]

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[Guest]

Ok well literally just got her in the driveway now ill truly know what im working with cuz I might be wrong on the year

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Yes.

[joshua52mcclain]

Ok it is a 92 firebird witch has a 3.1 ill be doin a good amount of homework before I decide what route im going to take Im take a sc off a gtp and make a custom plenum and notch the fire wall for the rear facing intake or turbo set up but I know alittle more about sc I've only ever had one turbo car factory turbo never got into that motor 96gsx awd

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[Guest]

You would have to cut a hole in the hood for the super to sit onto of a (custom) plenum. There's just not enough space to lower the SC low enough AND get the injectors in a good location to fire into each runner due to the narrow bank angle of the 60 degree V6.

[joshua52mcclain]

I figured that so I planned on doing a large cowl hood if I did go sc its all comes down to cost I was even thinking there are alot of videos on diy sc out of a turbo and some gears out of a 50cc dirtbike trans idk it a thought right now im just looking for a 3.4 to build then swap later on thats when I figure out sc/turbo

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[Guest]

Why go through the trouble of making the turbo less efficient?

Just go turbo and be done with it. It will under the stock good, users otherwise wasted energy to increase the overall power output and they are really quite simple to install.