[Z06] FAST Introduces NEW Runner Combos/Stacks for 102mm
12-17-2014, 11:13 PM
#21
Pro
Thread Starter
The different runner lengths will "shift" the power in the band. We took a seminar presented by Kinsler at PRI, and they basically said:
-A well-designed manifold that is properly matched to the engine’s requirements will make more torque and horsepower than a manifold which is mismatched to the engine.
-A longer intake runner tends to keep the air moving in the right direction in spite of the reversionary pressure pulse that is trying to push it backwards.
-Shorter runners, on the other hand, usually flow better at higher engine rpm. Reducing the length of the runners may allow the engine to make more power at the top end, but the trade-off may be a loss of power and torque at lower speeds.
If you are building a low rpm torque motor, you want an intake manifold with longer high velocity runners. On the other hand, if you are building a high revving motor, you will probably want a manifold with shorter runners or runners with a larger cross-sectional area to flow more air.
-A well-designed manifold that is properly matched to the engine’s requirements will make more torque and horsepower than a manifold which is mismatched to the engine.
-A longer intake runner tends to keep the air moving in the right direction in spite of the reversionary pressure pulse that is trying to push it backwards.
-Shorter runners, on the other hand, usually flow better at higher engine rpm. Reducing the length of the runners may allow the engine to make more power at the top end, but the trade-off may be a loss of power and torque at lower speeds.
If you are building a low rpm torque motor, you want an intake manifold with longer high velocity runners. On the other hand, if you are building a high revving motor, you will probably want a manifold with shorter runners or runners with a larger cross-sectional area to flow more air.
12-18-2014, 07:11 AM
#22
Burning Brakes
The different runner lengths will "shift" the power in the band. We took a seminar presented by Kinsler at PRI, and they basically said:
-A well-designed manifold that is properly matched to the engine’s requirements will make more torque and horsepower than a manifold which is mismatched to the engine.
-A longer intake runner tends to keep the air moving in the right direction in spite of the reversionary pressure pulse that is trying to push it backwards.
-Shorter runners, on the other hand, usually flow better at higher engine rpm. Reducing the length of the runners may allow the engine to make more power at the top end, but the trade-off may be a loss of power and torque at lower speeds.
If you are building a low rpm torque motor, you want an intake manifold with longer high velocity runners. On the other hand, if you are building a high revving motor, you will probably want a manifold with shorter runners or runners with a larger cross-sectional area to flow more air.
-A well-designed manifold that is properly matched to the engine’s requirements will make more torque and horsepower than a manifold which is mismatched to the engine.
-A longer intake runner tends to keep the air moving in the right direction in spite of the reversionary pressure pulse that is trying to push it backwards.
-Shorter runners, on the other hand, usually flow better at higher engine rpm. Reducing the length of the runners may allow the engine to make more power at the top end, but the trade-off may be a loss of power and torque at lower speeds.
If you are building a low rpm torque motor, you want an intake manifold with longer high velocity runners. On the other hand, if you are building a high revving motor, you will probably want a manifold with shorter runners or runners with a larger cross-sectional area to flow more air.
12-18-2014, 08:01 AM
#23
Melting Slicks
MSD Manifold
It will be interesting to see how the MSD manifold will perform. It looks like the runners are a little longer than the new Fast runners (not the really short ones) but shorter than the existing ones that flute downward. The question will be the total new design and plenums on either side thus the squareish shape will that still give you the low speed response but the longer straight runner still giving high rpm power? I presume the squarish design allows a slightly longer runner than the half moon top. If I look at the graph (which goes from 3,000-7,000 rpm) on the lingenfelter 575 hp motor it looks fairly close until about 4,800 rpm with the real delta coming on at about 5,800 rpm. This 427 motor is very similar too many of the C6 guys here who are putting out 550-600 rwhp now. Also it will be interesting to see on how easy or not these are to tune.
12-18-2014, 03:18 PM
#24
I’d caution folks to not make decisions based on dyno results, unless peak power is your only consideration. Drivability issues occur at engine speeds that are very rarely represented on a dyno pull, specifically – under 2000 rpm.
Air flow through an intake manifold and cylinder head port is bi-directional. Whenever you have an open plenum, reverse flow from one cylinder effects another cylinder due to pressure wave interaction. The runner design greatly influences this relationship. When the runner is shorter and/or its total area is reduced, this sharing relationship is increased in the idle, off idle and mid-range engine speeds. A longer runner helps to reduce the sharing relationship. ITB are the only way to completely divorce cylinders from one another, but they are very difficult to retro-fit when hood clearance is low, and they are expensive and difficult to tune. I am obviously speaking to N/A engines. Boosted engines behave differently.
Air movement to/from the cylinder is probably the most complex aspect of IC engine design and theory. Just search the internet for the terms “IC engine finite-amplitude waves and Helmholtz resonation ” and you’ll get a taste of it.
Air flow through an intake manifold and cylinder head port is bi-directional. Whenever you have an open plenum, reverse flow from one cylinder effects another cylinder due to pressure wave interaction. The runner design greatly influences this relationship. When the runner is shorter and/or its total area is reduced, this sharing relationship is increased in the idle, off idle and mid-range engine speeds. A longer runner helps to reduce the sharing relationship. ITB are the only way to completely divorce cylinders from one another, but they are very difficult to retro-fit when hood clearance is low, and they are expensive and difficult to tune. I am obviously speaking to N/A engines. Boosted engines behave differently.
Air movement to/from the cylinder is probably the most complex aspect of IC engine design and theory. Just search the internet for the terms “IC engine finite-amplitude waves and Helmholtz resonation ” and you’ll get a taste of it.
12-18-2014, 05:48 PM
#25
So can you custom match the runners with the heads or applications to get best results and drivability with smooth powerband all across. Peak numbers dont mean anything you need total gain thru power band.. I hope the tuning will give the car nice drivability. In hoping someone with a goods n/a package will try one soon for some results.
Last edited by RamAir972003; 12-19-2014 at 09:28 AM.
12-19-2014, 08:19 AM
#26
Melting Slicks
Drivability
I agree with the above, the idle and the pooping-around-town features will be very important as if it is not done right the car becomes a chore to drive and that is no fun.
11-22-2015, 08:11 AM
#31
i talked to them a month ago it took so long cause after pri they scraped the the design and started over they did not like how they tested out but he assured my first of the year all tested tooling and parts numbers are there but its only for ls3 port since there is 10-1 compared to a ls7 he had no answer when we can expect these for ls7 so it will be another year
11-25-2015, 07:56 AM
#32
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04-10-2016, 11:14 PM
#36