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Hi guys these are the results from the intake swap. the pic is hard to see but the thick lines are the fast 92 and the thin lines are the msd. the msd is a mid length runner ported by tony mamo. i posted the cam card as well. if you cant see the car made 525/442 peak power at 6250 on the fast. and 541/434 peak power at 6550 on the msd. engine is a 416 12.1 compression with trickflow 235s from TEA with the big exhaust ports for nitrous. cam specs are 243/251 at .050 on a 114.0 lsa. kooks 1 7/8ths headers. all through a t56 in a c5 corvette. Was hoping to see a little more power at a way higher rpm. just wondering what everyone thinks. seems like the cam may be holding it back at this point.
Seems like the peak HP RPM should be higher than 6500. With that 52 degree IVC at 050. Typically, I'd expect a 416 to hit peak power at 6500 on a 47-ish degree IVC.
Would also be worth revving it to 7200 to see how well the power carries. Power advantage on the MSD is past peak. It hangs on longer and drops slower, allowing you to stretch shift points.
we found it odd that it peaked so low on a mid runner intake as well. we were expecting the tq loss but going from a 92 to a 102 as well as being ported mid length runner would have picked up more than 20hp peak. we were expecting a much different power curve going mid runner.
ya we are invested pretty deep into the ported msd right now. kind of hoping to get some insight. i would definitely agree on the overall better curve on the fast 92. kind of an underwhelming result for sure
I agree. It was strongest thru 80% of the curve. Only at the VERY TOP did the MSD come out. NOT enough....
Originally Posted by Funskippymidget
ya we are invested pretty deep into the ported msd right now. kind of hoping to get some insight. i would definitely agree on the overall better curve on the fast 92. kind of an underwhelming result for sure
Yours did almost exactly what mine did, but the curves crossed at different RPM. On mine, the fast was better up to 6400 rpm. Above that, msd was better. And the further it revved the bigger the gap grew. Looking back at the two curves your torque curve is wider and flatter on the msd. That was also like mine.
I actually opted to stick with the msd for a few reasons:
1. I found the wider, flatter, smoother torque curve more predictable.
2. Since I shift at 7500, I found the MSD made higher average power from 5000 to 7500 rpm, which is how my splits look.
Having said that, I think if you revved both pulls out to 7300, you'd see a tremendous gain in power past peak. And don't listen to people who think you shift at peak power. There's a LOT more power from 6500-7300 rpm than there is from 4000-5000 the next gear up.
Yours did almost exactly what mine did, but the curves crossed at different RPM. On mine, the fast was better up to 6400 rpm. Above that, msd was better. And the further it revved the bigger the gap grew. Looking back at the two curves your torque curve is wider and flatter on the msd. That was also like mine.
I actually opted to stick with the msd for a few reasons:
1. I found the wider, flatter, smoother torque curve more predictable.
2. Since I shift at 7500, I found the MSD made higher average power from 5000 to 7500 rpm, which is how my splits look.
Having said that, I think if you revved both pulls out to 7300, you'd see a tremendous gain in power past peak. And don't listen to people who think you shift at peak power. There's a LOT more power from 6500-7300 rpm than there is from 4000-5000 the next gear up.
Mine peaks at 6750 with the port fast 90. I shift around 7200 i see this to often in real world where people want to shift at peak power then wonder why they are not running what they should. Good post
My ls7 block based 427 with off the shelf TFS 235s, 12:1 compression and a vengence ported fast 92 peaked between 6100 and 6200 as well. My cam is 24x/25x 624/624 on 112. It would have been interesting to see how it would have looked through 7,200.
ya we are invested pretty deep into the ported msd right now. kind of hoping to get some insight. i would definitely agree on the overall better curve on the fast 92. kind of an underwhelming result for sure
i would assume there is tons of tq on tap for driving with the msd. Turn that thing 7200 and msd will win at the track
well atleast im on par with everyone else. We're going to run it out to 7200ish and see what it does. It does have a really smooth feel with this new manifold which is nice
well atleast im on par with everyone else. We're going to run it out to 7200ish and see what it does. It does have a really smooth feel with this new manifold which is nice
well atleast im on par with everyone else. We're going to run it out to 7200ish and see what it does. It does have a really smooth feel with this new manifold which is nice
Yeah. I felt like on mine, I went from a triple-hump torque curve to a smooth broad curve. I mean you'd think looking at the curves I'd have liked the fast better, because it was higher through peak torque, but I actually preferred the msd for the smoother curve and less rpm areas where the motor sort of broke up a bit. I attributed it to harmonics with the intake runner and IVC but its a guess honestly.
12-13-2017, 08:21 PM
"mamofied"msd vs non-ported fast 92 
