New 90MM 8.1L Intake Manifold
#21
We ran all of our manifolds on Sunday and learned a few things. The cool gap manifold, with it's longer runners made slightly more torque than the shorter runner new prototype manifold. However, the shorter runner manifold really takes off past 4500rpm, and it makes more power than the cool gap by 5400-5500 rpm.
The modified stock manifold produces great torque and midrange, but even with all the modifications we make to it starts to fall off around 5200 rpm.
The motor we used was a marine engine so it's rev limiter was (non-adjustable) set at 5400-5500 rpm, so we don't have a really good idea yet of where the short runner prototype manifold falls off, but we're guessing around 6200-6400 rpm based on what we saw. We'll be running more tests with the 540 engine soon to see what's possible with a street motor.
The modified stock manifold produces great torque and midrange, but even with all the modifications we make to it starts to fall off around 5200 rpm.
The motor we used was a marine engine so it's rev limiter was (non-adjustable) set at 5400-5500 rpm, so we don't have a really good idea yet of where the short runner prototype manifold falls off, but we're guessing around 6200-6400 rpm based on what we saw. We'll be running more tests with the 540 engine soon to see what's possible with a street motor.
#22
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I think this about solidifies my plan to swap to a 540ci 8.1. My modded TBI runs stronger than a new stock 8.1 Burb but at that, the TBI is tapped out. Also, this OBD1 computer bullshit is for the birds, it might be cheap but that's about the only advantage I see.
#23
I just did a 496 swap on a 1993 3500. And it runs mucho better then before. If you need help with swap info send me an email. Edward.coss@Gmail.com
#24
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I just did a 496 swap on a 1993 3500. And it runs mucho better then before. If you need help with swap info send me an email. Edward.coss@Gmail.com
I did finally get moved to Dallas, BTW.
#30
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The 540 suburban just got the ported manifold, made a huge difference over 3k! The power delivery doesn't end at 4k now, it pulls solid to 5500 or so. Also the exhaust note has changed at WOT. The engine sounds like its got a four barrel on it whereas before it sounded very... asthmatic / stock chevy truck. Dyno day is this week, I'll report back.
If I haven't already posted this, here's the baseline dyno video: 540 Stroker Kit Baseline Dyno