New Product: High-Performance Intake Runners for the 32v 928
07-09-2010, 11:56 AM
#1
Developer
Thread Starter
New Product: High-Performance Intake Runners for the 32v 928
High Performance Intake Runners commercially available for the 928, so making your own intake manifold/system just got easier than its ever been.
Price and Ordering Information here:
http://www.928motorsports.com/parts/intake_runners.php
Design Objectives:
Our design goal was to make an intake
runner that would:
1) out-perform the stock intake runners, and
2) be of a modular design useful for multiple head and plenum configurations
(single plenum, dual plenums, and individual throttle bodies), and
3) be robust enough to also handle both boosted and naturally aspirated
applications.
Doing the Math
Before the design of a complete intake manifold system can be begin, there are some measurements and calculations that should be done to make sure it performs as intended. The engine specs, plus the intake runner length and diameter effect the volume and velocity of the air charge, and locate the power band within the desired RPM range.
Careful engineering also allows the pressure waves known as the “Helmholtz effect” to increase flow at the back of the intake valve just as it opens, thereby increasing volumetric efficiency by as much as 10%. To take advantage of this, proper intake bells must be used to create the pressure wave reversal to send the pulse back to the valve from where it came.
As this article is about the development of the intake runners only, and our customers may want to finish their system with individual throttle bodies (ITB’s) or single or dual plenum manifolds; the discussion and calculations for finished total runner length and plenum size have been omitted.
Price and Ordering Information here:
http://www.928motorsports.com/parts/intake_runners.php
Design Objectives:
Our design goal was to make an intake
runner that would:
1) out-perform the stock intake runners, and
2) be of a modular design useful for multiple head and plenum configurations
(single plenum, dual plenums, and individual throttle bodies), and
3) be robust enough to also handle both boosted and naturally aspirated
applications.
Doing the Math
Before the design of a complete intake manifold system can be begin, there are some measurements and calculations that should be done to make sure it performs as intended. The engine specs, plus the intake runner length and diameter effect the volume and velocity of the air charge, and locate the power band within the desired RPM range.
Careful engineering also allows the pressure waves known as the “Helmholtz effect” to increase flow at the back of the intake valve just as it opens, thereby increasing volumetric efficiency by as much as 10%. To take advantage of this, proper intake bells must be used to create the pressure wave reversal to send the pulse back to the valve from where it came.
As this article is about the development of the intake runners only, and our customers may want to finish their system with individual throttle bodies (ITB’s) or single or dual plenum manifolds; the discussion and calculations for finished total runner length and plenum size have been omitted.
07-09-2010, 12:01 PM
#2
Developer
Thread Starter
Injector placement
Owing to the size and type of injectors available to Porsche when the original manifold was designed, a fairly large intrusion into the intake runner exists
to make room for the Generation 2 injectors.
The advent of the modern Generation 3 injector allows us to reduce this intrusion into the runner, and permits more air to travel though.
In addition, we canted the runner away from the injector slightly, which had several benefits.
Owing to the size and type of injectors available to Porsche when the original manifold was designed, a fairly large intrusion into the intake runner exists
to make room for the Generation 2 injectors.
The advent of the modern Generation 3 injector allows us to reduce this intrusion into the runner, and permits more air to travel though.
In addition, we canted the runner away from the injector slightly, which had several benefits.
07-09-2010, 12:05 PM
#3
Developer
Thread Starter
Taper
There are two methods of “natural supercharging”, that is, increasing the velocity of the air at the back of the intake valve.
The first is the Helmholtz Effect, using proper inlet bells to reverse the pressure
wave in combination with intake runner length to time the pulse so it arrives at
the back of the valve just as the valve opens; and the second is runner taper.
A tapered intake runner increases air velocity at the back of the valve, and is an
inexpensive way to gain HP from your intake system.
Taper and intake runner length are often overlooked in ITB setups, where the ITB’s are mounted directly to the heads or very close thereto. In our design, the ITB’s can be mounted atop our runners, and benefit from the midrange torque that the runner length provides and the velocity increase from the tapered runner.
All systems, boosted or NA, whether using single or dual plenums or ITBs benefit from the increase in velocity that a good tapered runner provides.
The dimensions at the base of the runner were set after the head was fully ported using a special 5-axis CNC process that 928 Motorsports developed.
Working up from the finished ported head, we established the diameter and taper desired in the intake runner, the length of the runner, the injector angle and fitment, and the mounting surface for the plenum.
There are two methods of “natural supercharging”, that is, increasing the velocity of the air at the back of the intake valve.
The first is the Helmholtz Effect, using proper inlet bells to reverse the pressure
wave in combination with intake runner length to time the pulse so it arrives at
the back of the valve just as the valve opens; and the second is runner taper.
A tapered intake runner increases air velocity at the back of the valve, and is an
inexpensive way to gain HP from your intake system.
Taper and intake runner length are often overlooked in ITB setups, where the ITB’s are mounted directly to the heads or very close thereto. In our design, the ITB’s can be mounted atop our runners, and benefit from the midrange torque that the runner length provides and the velocity increase from the tapered runner.
All systems, boosted or NA, whether using single or dual plenums or ITBs benefit from the increase in velocity that a good tapered runner provides.
The dimensions at the base of the runner were set after the head was fully ported using a special 5-axis CNC process that 928 Motorsports developed.
Working up from the finished ported head, we established the diameter and taper desired in the intake runner, the length of the runner, the injector angle and fitment, and the mounting surface for the plenum.
07-09-2010, 12:06 PM
#4
Developer
Thread Starter
Design Drawings
Computer-Aided Design of this part was a must. It afforded us the opportunity to model many different iterations, and make changes to transitions and radiuses rapidly.
Ryan Silva operated the Solid Works software, and co-designed the finished part with Carl Fausett from 928 Motorsports LLC.
Changes and adjustments to fitment were made via Rapid Prototyping and fed back into the computer model.
Computer-Aided Design of this part was a must. It afforded us the opportunity to model many different iterations, and make changes to transitions and radiuses rapidly.
Ryan Silva operated the Solid Works software, and co-designed the finished part with Carl Fausett from 928 Motorsports LLC.
Changes and adjustments to fitment were made via Rapid Prototyping and fed back into the computer model.
07-09-2010, 12:07 PM
#5
Developer
Thread Starter
Material Choice and Material Specs
Glass-reinforced Nylon (Nylon 12 GF) and later, Micro-Carbon Fiber* were selected for their strength to weight ratios and relatively low cost of production when compared to an aluminum or similar casting.
Their insulative properties to help keep the plenums and injectors cool was also a plus.
Weight
In Nylon GF (as tested) a pair of our intake runners weigh exactly 4lbs. Optionally, we can also manufacture them in Nylon MCF (Micro-Carbon Fiber) where the runners would now be 3.096 lbs. In comparison, if made in aluminum, the same part would weigh 8.0 pounds.
REFERENCE DATA
Cast Aluminum (2000 series) weighs 0.0997lb/in^3
Aluminum billet (6061) weighs 0.0975 lb/in^3
Nylon GF is 0.050 lb/in^3
Nylon MCF is 0.0387 lb/in3
*Micro-Carbon Fiber uses very short strands of carbon fiber, instead of traditional carbon-fiber mat. It lends itself to radiuses better than fiber mat, and has omni-directional strength and stability.
Glass-reinforced Nylon (Nylon 12 GF) and later, Micro-Carbon Fiber* were selected for their strength to weight ratios and relatively low cost of production when compared to an aluminum or similar casting.
Their insulative properties to help keep the plenums and injectors cool was also a plus.
Weight
In Nylon GF (as tested) a pair of our intake runners weigh exactly 4lbs. Optionally, we can also manufacture them in Nylon MCF (Micro-Carbon Fiber) where the runners would now be 3.096 lbs. In comparison, if made in aluminum, the same part would weigh 8.0 pounds.
REFERENCE DATA
Cast Aluminum (2000 series) weighs 0.0997lb/in^3
Aluminum billet (6061) weighs 0.0975 lb/in^3
Nylon GF is 0.050 lb/in^3
Nylon MCF is 0.0387 lb/in3
*Micro-Carbon Fiber uses very short strands of carbon fiber, instead of traditional carbon-fiber mat. It lends itself to radiuses better than fiber mat, and has omni-directional strength and stability.
Last edited by Carl Fausett; 07-09-2010 at 12:23 PM.
07-09-2010, 12:08 PM
#6
Developer
Thread Starter
Pressure and Thermal Testing
Our choice of materials needed to be tested for burst strength on boosted engines and thermal stability on hot race engines.
Our data shows the cylinder head of the 928 engine to be at about 185 deg F surface temp at full load, so we applied 200 degrees to the glass-filled nylon intake runner and 20 to 40 pounds of pressure to test it.
The question we needed to answer is how much of the nylons burst strength we would lose at 200 deg F.
Using a timing solenoid and pneumatic switch mechanism, the pressure in the runner would go to 20 psi and hold for 9 seconds, then release to zero for one second, then repeat. This cycle repeated 6 times per minute, allowing us very high cycling numbers far in excess of what the engine would see in a given race.
After we had logged 4,680 cycles (9 seconds on, 1 second off) on the manifold at 200 degrees at 10 psi without
any failure, we raised the pressure to 20 psi while still holding the GF nylon the at 200 degrees. We ran another
8,640 cycles like that also without any failure. We measured elongation of the part to be less than .002 per cycle, well within limits and far away from the materials rated tensile strength.
Next, we raised the manifold pressure from 20 psi to 40 psi, and the RTV silicone gasket sealant blew out.
To continue high-pressure testing of the runner, we moved the runner to an actual cylinder head of the engine,
using the stock intake manifold gasket and no RTV. Now we could run at 40 psi and did so for 8,640 cycles without any measureable changes or failure.
These tests proved to us our intake runner could withstand both the under-hood temperatures and the pressures it would need to survive in our application.
Our choice of materials needed to be tested for burst strength on boosted engines and thermal stability on hot race engines.
Our data shows the cylinder head of the 928 engine to be at about 185 deg F surface temp at full load, so we applied 200 degrees to the glass-filled nylon intake runner and 20 to 40 pounds of pressure to test it.
The question we needed to answer is how much of the nylons burst strength we would lose at 200 deg F.
Using a timing solenoid and pneumatic switch mechanism, the pressure in the runner would go to 20 psi and hold for 9 seconds, then release to zero for one second, then repeat. This cycle repeated 6 times per minute, allowing us very high cycling numbers far in excess of what the engine would see in a given race.
After we had logged 4,680 cycles (9 seconds on, 1 second off) on the manifold at 200 degrees at 10 psi without
any failure, we raised the pressure to 20 psi while still holding the GF nylon the at 200 degrees. We ran another
8,640 cycles like that also without any failure. We measured elongation of the part to be less than .002 per cycle, well within limits and far away from the materials rated tensile strength.
Next, we raised the manifold pressure from 20 psi to 40 psi, and the RTV silicone gasket sealant blew out.
To continue high-pressure testing of the runner, we moved the runner to an actual cylinder head of the engine,
using the stock intake manifold gasket and no RTV. Now we could run at 40 psi and did so for 8,640 cycles without any measureable changes or failure.
These tests proved to us our intake runner could withstand both the under-hood temperatures and the pressures it would need to survive in our application.
Last edited by Carl Fausett; 07-09-2010 at 12:28 PM.
07-09-2010, 12:09 PM
#7
Developer
Thread Starter
Colorization
We didn't think many customers would warm to the natural-nylon look, and its tendency to hold greasy fingerprints and dirt.
Early experimentation with dyes showed us how to color the casting in a manner that was pleasing to the customer, and we have already developed a flat black, red, and an “aluminum gray” colorization to the GF nylon.
Another benefit of our colorization process is that the dyes penetrate the nylon
to a depth of about .003”, making all but the deepest scratches invisible, and far more durable than paint.
We didn't think many customers would warm to the natural-nylon look, and its tendency to hold greasy fingerprints and dirt.
Early experimentation with dyes showed us how to color the casting in a manner that was pleasing to the customer, and we have already developed a flat black, red, and an “aluminum gray” colorization to the GF nylon.
Another benefit of our colorization process is that the dyes penetrate the nylon
to a depth of about .003”, making all but the deepest scratches invisible, and far more durable than paint.
Last edited by Carl Fausett; 07-09-2010 at 12:30 PM.
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07-09-2010, 12:10 PM
#8
Developer
Thread Starter
Flow Bench Testing
The finished intake runners were flow-bench tested as were the original Porsche 32v intake manifold runners.
We checked all the runners in the OEM intake manifold and found cylinder #7 to be the most typical, and based our measurements there.
Measurements were conducted in such a way as to isolate the runner design only, and remove the plenums from consideration.
The stock intake runners flowed 244.75 CFM.
The 928MS intake runners flowed 356.89 CFM.
All tests were performed on the same day on the same machine, and at 28.5 Hg.
The finished intake runners were flow-bench tested as were the original Porsche 32v intake manifold runners.
We checked all the runners in the OEM intake manifold and found cylinder #7 to be the most typical, and based our measurements there.
Measurements were conducted in such a way as to isolate the runner design only, and remove the plenums from consideration.
The stock intake runners flowed 244.75 CFM.
The 928MS intake runners flowed 356.89 CFM.
All tests were performed on the same day on the same machine, and at 28.5 Hg.
Last edited by Carl Fausett; 07-09-2010 at 12:32 PM.
07-09-2010, 12:11 PM
#9
Developer
Thread Starter
Adaptability
The finished product lends itself nicely to Individual Throttle Bodies, Single Plenum and Dual Plenum manifolds, boosted or naturally aspirated.
Where single-plenum manifolds are concerned, the strength of the material in tension needs to be checked as the heads move away from each other because of thermal expansion of the aluminum block.
Our tests show that the Porsche 928 engine expansion from cold to hot engine, measured across the heads, is .034” ± .005” This is well below the material strength of Nylon GF and Nylon MCF, showing that single-plenum manifolds would be no problem with these runners.
Fuel Rail Mounts Built In
In keeping with our concept of modular design, the fuel rail mounts were designed-in to the intake runners in such a way that easy access to the mounting bolts is still maintained. This permits removal of the intake as a unit with injectors attached, as shown.
The finished product lends itself nicely to Individual Throttle Bodies, Single Plenum and Dual Plenum manifolds, boosted or naturally aspirated.
Where single-plenum manifolds are concerned, the strength of the material in tension needs to be checked as the heads move away from each other because of thermal expansion of the aluminum block.
Our tests show that the Porsche 928 engine expansion from cold to hot engine, measured across the heads, is .034” ± .005” This is well below the material strength of Nylon GF and Nylon MCF, showing that single-plenum manifolds would be no problem with these runners.
Fuel Rail Mounts Built In
In keeping with our concept of modular design, the fuel rail mounts were designed-in to the intake runners in such a way that easy access to the mounting bolts is still maintained. This permits removal of the intake as a unit with injectors attached, as shown.
Last edited by Carl Fausett; 07-09-2010 at 12:35 PM.
07-09-2010, 12:12 PM
#11
Developer
Thread Starter
Final Assembly:
These pictures show one possible conclusion to the intake manifold design using our hi-flow runners.
The application for this engine is a high-torque road racing motor, and taking a shot at the Land Speed record for Porsche 928’s.
This Intake Runner was the last step to a total improvement of air flow throughout the 32v 928 engine.
First, the new intake runners are mounted to the heads…
Then the plenum floor is put in place. We can provide a CNC-cut plenum floor for these intake runners upon request. It makes fabricating your own plenum easy!
The bells that make up the top of the intake runners were set at the proper height off the plenum floor...
These pictures show one possible conclusion to the intake manifold design using our hi-flow runners.
The application for this engine is a high-torque road racing motor, and taking a shot at the Land Speed record for Porsche 928’s.
This Intake Runner was the last step to a total improvement of air flow throughout the 32v 928 engine.
First, the new intake runners are mounted to the heads…
Then the plenum floor is put in place. We can provide a CNC-cut plenum floor for these intake runners upon request. It makes fabricating your own plenum easy!
The bells that make up the top of the intake runners were set at the proper height off the plenum floor...
Last edited by Carl Fausett; 07-09-2010 at 12:40 PM.
07-09-2010, 12:13 PM
#12
Developer
Thread Starter
We experimented with mock-ups of both round-roof plenums and flat-roof plenums.
For this application, the flat-roof was preferred as it placed our plenum volume closest to the ideal size we had calculated.
The sides, floor and roof of our plenum is made from 0.25” 6061 aluminum. That’s thicker than most would use, but we are designing for up to 30 psi of
boost, and that’s the reason for the wall thickness.
Now the plenum sides are added, as well as the inlet tubes at the rear of each plenum.
A “balance tube” is often only 3/4” in diameter, just enough to balance out plenum pressures. This one is a full 3.0” in diameter, and does more than that...
Owing to the unique firing order of the 928, this balance tube will actually feed and equilibrate the forward-most cylinders (cyls 1 and 5) with air from the opposite plenum on every cycle.
For this application, the flat-roof was preferred as it placed our plenum volume closest to the ideal size we had calculated.
The sides, floor and roof of our plenum is made from 0.25” 6061 aluminum. That’s thicker than most would use, but we are designing for up to 30 psi of
boost, and that’s the reason for the wall thickness.
Now the plenum sides are added, as well as the inlet tubes at the rear of each plenum.
A “balance tube” is often only 3/4” in diameter, just enough to balance out plenum pressures. This one is a full 3.0” in diameter, and does more than that...
Owing to the unique firing order of the 928, this balance tube will actually feed and equilibrate the forward-most cylinders (cyls 1 and 5) with air from the opposite plenum on every cycle.
Last edited by Carl Fausett; 07-09-2010 at 12:43 PM.
07-09-2010, 12:14 PM
#13
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DANG Carl!!! That is VERY IMPRESSIVE and I KNOW it wasn't cheap to do either!
KUDOS!!!
KUDOS!!!
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07-09-2010, 12:14 PM
#14
Developer
Thread Starter
The finished plenums are placed atop the intake runners, and are waiting for
the intake tubing and throttle body to be attached.
They will handle 30 psi of boost, move enough air to support 800+ HP, and still fit under the hood of the 928!
the intake tubing and throttle body to be attached.
They will handle 30 psi of boost, move enough air to support 800+ HP, and still fit under the hood of the 928!
Last edited by Carl Fausett; 07-09-2010 at 12:45 PM.
07-09-2010, 12:16 PM
#15
Developer
Thread Starter
Rounding It Out
Of course a big intake manifold alone doesn't make HP. You need the rest of the engine to match!
We have done the research to develop maximum-flow from the 928 32v heads, and have them flowing as much as 324 CFM at .450” of intake valve lift. This was a 56.6% improvement over stock 928 heads.
A complete description with flow charts about our CNC head porting program is available at our website here:
http://www.928motorsports.com/servic...alve_heads.php
With the big valves to match:
http://www.928motorsports.com/parts/32v_valves.php
In addition, the high performance camshafts needed to produce these lift and flow numbers have also been developed and tested. More information about our highperformance Camshafts is available at our website here:
http://www.928motorsports.com/parts/camshafts.php
And you need the right exhaust headers; designed to properly port-match these monster heads, and we have them too. More information about these headers is available at our website here:
http://www.928motorsports.com/parts/big_port_header.php
Finally, you may want a modern stand-alone Engine Management System to dial it all in and control those big injectors you will use to feed the beast. We have that for you too, here:
http://www.928motorsports.com/parts/...management.php
Of course a big intake manifold alone doesn't make HP. You need the rest of the engine to match!
We have done the research to develop maximum-flow from the 928 32v heads, and have them flowing as much as 324 CFM at .450” of intake valve lift. This was a 56.6% improvement over stock 928 heads.
A complete description with flow charts about our CNC head porting program is available at our website here:
http://www.928motorsports.com/servic...alve_heads.php
With the big valves to match:
http://www.928motorsports.com/parts/32v_valves.php
In addition, the high performance camshafts needed to produce these lift and flow numbers have also been developed and tested. More information about our highperformance Camshafts is available at our website here:
http://www.928motorsports.com/parts/camshafts.php
And you need the right exhaust headers; designed to properly port-match these monster heads, and we have them too. More information about these headers is available at our website here:
http://www.928motorsports.com/parts/big_port_header.php
Finally, you may want a modern stand-alone Engine Management System to dial it all in and control those big injectors you will use to feed the beast. We have that for you too, here:
http://www.928motorsports.com/parts/...management.php
Last edited by Carl Fausett; 07-09-2010 at 12:48 PM.