Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

HIGHWAYMAN: Bringing the Devore 928 back from the dead

 
Old 11-03-2017, 02:16 PM
  #766  
ptuomov
Super User
 
ptuomov's Avatar
 
Join Date: Jan 2009
Location: MA
Posts: 4,624
Default

Originally Posted by Carl Fausett View Post
There is a difference between building for a big show-off number on a dyno; and building for good throttle-response and drive-ability. A desire for good throttle control in the mid-range.

Yes, ptuomov, your math is all about max HP output and its not wrong.
But on race day (or for the street), you can benefit from the better throttle control a slightly smaller TB will provide. BT, DT.
Do you agree with the rules of thumb that a street car should have a throttle sized to produce a 2.5% power loss and a race car should have a throttle sized to produce a 1% power loss? Those aren't gospel, they're just what I've observed in competent high-budget efforts.

By my math, the 2.5% power loss street car throttle would be sized at 97mm for this engine, assuming that the motor would make 550hp with a very large throttle body. The equation for @28" CFM is 1.6*550/sqrt((2.5/100)*(14.7-0.7)) = 1487 and the equation for the throttle plate diameter in mm is sqrt(1.6*550/sqrt((2.5/100)*(14.7-0.7))/0.1567) = 97mm.

I believe (but of course don't know) that had Porsche built this kind of 550hp motor for the street with a single throttle blade, they would have put in something like 97mm throttle body.

Personally, I think that 90mm throttle body is too small for this engine even for a street car, let alone for a race car.
ptuomov is online now  
Old 11-03-2017, 02:51 PM
  #767  
Catorce
Basic Sponsor
Rennlist
Site Sponsor

Thread Starter
 
Catorce's Avatar
 
Join Date: Nov 2016
Location: Orange County
Posts: 1,423
Default

Originally Posted by GregBBRD View Post
Beautiful fabrication!

Looks like a short runner American Tunnel Ram, except for the 90 degree and 180 degree air flow direction changes required for the air to get to the intake valves.

What is your target power range?

Thanks Greg,

I know nothing about this manifold specifically; it was Carl's brainchild - I'll let him answer.

As to power, I believe we did 510 HP on the engine dyno with the stock manifold plus spacers. There is no set goal other than to exceed that number; i would be happy with an additional 50hp from this manifold but in the end that might be asking too much; we are all going to find out one way or the other if this thing works as good as it looks......
__________________
Current cars:
70 914-6 - 2.7L screamer
73 911T Carrera RS Clone, 3.6 power
75 911 Targa - RSR width 930 motor
78 928 - DEVORE CAR, 6.54L
83 911 Euro SC - 3.2 Short Stroke!
88 928S4 5 speed
02 911 Targa
04 911 40th Anniv
07 997 Twin Turbo 6MT - Techart beauty
09 997 Twin Turbo 6MT - Factory Aerokit
11 Camaro SS - 6MT Z28 Spec, V7Ysi 850whp
12 McLaren 12C
17 McLaren 570S
The only reproduction 3.6 flat six engine cases on the planet
www.taorminaracingdesigns.com


Catorce is offline  
Old 11-03-2017, 04:22 PM
  #768  
Carl Fausett
Developer
Rennlist Member


Rennlist
Site Sponsor

 
Carl Fausett's Avatar
 
Join Date: Dec 2001
Location: Horicon, WI
Posts: 6,590
Default

As a point of reference: the stock throttle body on the 5.0L S4 motor is 75mm. The throttle body I ran on the extrude-honed intake was 90mm throttle body.
__________________
Questions? Tech Support?
Call 920-485-0928
International 001-920-485-0928
Email: [email protected]
Website: https://928motorsports.com/
Instructions: http://www.928motorsports.com/install.php


Carl Fausett is online now  
Old 11-03-2017, 04:29 PM
  #769  
ptuomov
Super User
 
ptuomov's Avatar
 
Join Date: Jan 2009
Location: MA
Posts: 4,624
Default

Originally Posted by Catorce View Post
I know nothing about this manifold specifically; it was Carl's brainchild - I'll let him answer.

As to power, I believe we did 510 HP on the engine dyno with the stock manifold plus spacers. There is no set goal other than to exceed that number; i would be happy with an additional 50hp from this manifold but in the end that might be asking too much; we are all going to find out one way or the other if this thing works as good as it looks......
In my opinion, 560hp or 10% improvement over the ported stock manifold with 90mm throttle body should be there, as long as you spin the higher with this manifold and put a larger throttle body in it. Not that I've got much experience in this, just based on thinking about how the internal combustion engine works.
ptuomov is online now  
Old 11-03-2017, 04:52 PM
  #770  
SwayBar
Addict
Rennlist Member
 
SwayBar's Avatar
 
Join Date: Feb 2006
Location: Chicago Bears
Posts: 2,340
Default

Originally Posted by Catorce View Post
As to power, I believe we did 510 HP on the engine dyno with the stock manifold plus spacers. There is no set goal other than to exceed that number; i would be happy with an additional 50hp from this manifold
I think that will prove to be an extremely conservative number, and that this manifold's performance will surprise everyone.

Finally, a real performance intake for the 928...!
SwayBar is offline  
Old 11-05-2017, 01:53 AM
  #771  
928 GT R
Addict
Rennlist Member
 
928 GT R's Avatar
 
Join Date: Sep 2006
Location: Michigan
Posts: 1,462
Default

This thread is giving me some serious 6.57 L envy!

This show's what can happen when a dedicated owner/restorer teams up with an artful fabricator and an imaginative engineer to produce something that has never existed...

Well done!

I can't wait to see the dyne numbers and more importantly, how well it drives!
928 GT R is offline  
Old 11-05-2017, 02:01 PM
  #772  
Catorce
Basic Sponsor
Rennlist
Site Sponsor

Thread Starter
 
Catorce's Avatar
 
Join Date: Nov 2016
Location: Orange County
Posts: 1,423
Default

Originally Posted by 928 GT R View Post
This thread is giving me some serious 6.57 L envy!

This show's what can happen when a dedicated owner/restorer teams up with an artful fabricator and an imaginative engineer to produce something that has never existed...

Well done!

I can't wait to see the dyne numbers and more importantly, how well it drives!
Thanks!

I was just not willing to accept the dyno numbers we did on the extrude honed manifold as being the gospel.

There's a peculiar thing going on in the 928 community where there seems to be a blanket acceptance of certain aftermarket parts, and it there is no real development for some of these things because it costs money.

In the 928 world, there were essentially three manifolds that existed:

-Bone Stock

- A modified stock manifold either with spacers or some other sort of trickery.

- The legendary Carbon manifold, which was made by the gods themselves, could never be duplicated, and while it produced excellent results, it could not be bought by mere mortals, it's creator was lost to history, and it turned into a holy relic that was bestowed into the hands of a chosen few.

I was simply not willing to accept that, which is why I funded the development of a new manifold. If it works, you will ALL be able to buy it.

This is kind of my MO. No one was making Porsche Flat 6 engine cases either, and the community just accepted it even though you couldn't find a 3.6 case to save your life. So I decided to.

Now the only people who make Porsche motor castings on the planet are Porsche......

and ME.
__________________
Current cars:
70 914-6 - 2.7L screamer
73 911T Carrera RS Clone, 3.6 power
75 911 Targa - RSR width 930 motor
78 928 - DEVORE CAR, 6.54L
83 911 Euro SC - 3.2 Short Stroke!
88 928S4 5 speed
02 911 Targa
04 911 40th Anniv
07 997 Twin Turbo 6MT - Techart beauty
09 997 Twin Turbo 6MT - Factory Aerokit
11 Camaro SS - 6MT Z28 Spec, V7Ysi 850whp
12 McLaren 12C
17 McLaren 570S
The only reproduction 3.6 flat six engine cases on the planet
www.taorminaracingdesigns.com


Catorce is offline  
Old 11-05-2017, 03:15 PM
  #773  
SwayBar
Addict
Rennlist Member
 
SwayBar's Avatar
 
Join Date: Feb 2006
Location: Chicago Bears
Posts: 2,340
Default

Can you let us know the runner length and runner inside diameter?

The ID is the most important, and I'm just trying to gauge if there's any chance of it working on a 5.0.
SwayBar is offline  
Old 11-05-2017, 03:33 PM
  #774  
928sg
Resident 928 Modiholic
Rennlist Member
 
928sg's Avatar
 
Join Date: Mar 2013
Posts: 1,884
Default

Originally Posted by Catorce View Post
Thanks!

I was just not willing to accept the dyno numbers we did on the extrude honed manifold as being the gospel.

There's a peculiar thing going on in the 928 community where there seems to be a blanket acceptance of certain aftermarket parts, and it there is no real development for some of these things because it costs money.

In the 928 world, there were essentially three manifolds that existed:

-Bone Stock

- A modified stock manifold either with spacers or some other sort of trickery.

- The legendary Carbon manifold, which was made by the gods themselves, could never be duplicated, and while it produced excellent results, it could not be bought by mere mortals, it's creator was lost to history, and it turned into a holy relic that was bestowed into the hands of a chosen few.

I was simply not willing to accept that, which is why I funded the development of a new manifold. If it works, you will ALL be able to buy it.

This is kind of my MO. No one was making Porsche Flat 6 engine cases either, and the community just accepted it even though you couldn't find a 3.6 case to save your life. So I decided to.

Now the only people who make Porsche motor castings on the planet are Porsche......

and ME.
There are also have a dozen ITB setups running around... and several not running like mine still in the assembly stage
928sg is offline  
Old 11-05-2017, 06:44 PM
  #775  
Catorce
Basic Sponsor
Rennlist
Site Sponsor

Thread Starter
 
Catorce's Avatar
 
Join Date: Nov 2016
Location: Orange County
Posts: 1,423
Default

^true, but I was thinking purely of manifolds. ITBs are always an option.
__________________
Current cars:
70 914-6 - 2.7L screamer
73 911T Carrera RS Clone, 3.6 power
75 911 Targa - RSR width 930 motor
78 928 - DEVORE CAR, 6.54L
83 911 Euro SC - 3.2 Short Stroke!
88 928S4 5 speed
02 911 Targa
04 911 40th Anniv
07 997 Twin Turbo 6MT - Techart beauty
09 997 Twin Turbo 6MT - Factory Aerokit
11 Camaro SS - 6MT Z28 Spec, V7Ysi 850whp
12 McLaren 12C
17 McLaren 570S
The only reproduction 3.6 flat six engine cases on the planet
www.taorminaracingdesigns.com


Catorce is offline  
Old 11-05-2017, 06:45 PM
  #776  
Catorce
Basic Sponsor
Rennlist
Site Sponsor

Thread Starter
 
Catorce's Avatar
 
Join Date: Nov 2016
Location: Orange County
Posts: 1,423
Default

Originally Posted by SwayBar View Post
Can you let us know the runner length and runner inside diameter?

The ID is the most important, and I'm just trying to gauge if there's any chance of it working on a 5.0.
Sway,

At this time the numbers for this manifold are proprietary and confidential. Let's talk after we do some tests....

I don't think this manifold would benefit a 5.0. I have to believe Porsche squeezed all the power they could out of the stock manifold, but I could be wrong.
__________________
Current cars:
70 914-6 - 2.7L screamer
73 911T Carrera RS Clone, 3.6 power
75 911 Targa - RSR width 930 motor
78 928 - DEVORE CAR, 6.54L
83 911 Euro SC - 3.2 Short Stroke!
88 928S4 5 speed
02 911 Targa
04 911 40th Anniv
07 997 Twin Turbo 6MT - Techart beauty
09 997 Twin Turbo 6MT - Factory Aerokit
11 Camaro SS - 6MT Z28 Spec, V7Ysi 850whp
12 McLaren 12C
17 McLaren 570S
The only reproduction 3.6 flat six engine cases on the planet
www.taorminaracingdesigns.com


Catorce is offline  
Old 11-05-2017, 07:09 PM
  #777  
SwayBar
Addict
Rennlist Member
 
SwayBar's Avatar
 
Join Date: Feb 2006
Location: Chicago Bears
Posts: 2,340
Default

Yeah, I understand. As they say, it doesn't hurt to ask.
SwayBar is offline  
Old 11-05-2017, 07:40 PM
  #778  
ptuomov
Super User
 
ptuomov's Avatar
 
Join Date: Jan 2009
Location: MA
Posts: 4,624
Default

Originally Posted by Catorce View Post
Sway, At this time the numbers for this manifold are proprietary and confidential. Let's talk after we do some tests....

I don't think this manifold would benefit a 5.0. I have to believe Porsche squeezed all the power they could out of the stock manifold, but I could be wrong.
I don't think that they took the most power out of the 32-valve models' intake manifolds.

I think they did the S4 manifold the way they did it because they needed a certain (large) amount of torque at very low rpms to create a single engine that's nice to drive with both automatic and manual transmissions.

The first iteration of the manifold was actually on the S3. They patented the true dual plan intake runner arrangement of S3 that has 40cm pipes (50cm total induction length) and equally-space pulses in each plenum. The S3 manifold produces the two Helmholtz tuning peaks.







The second iteration S4 added the second zip tube with the resonance flappy valve. They also made the manifold more compact, which lead to unequal length runners (four 20cm and four 30cm runners). The flappy open mode adds the torque peak in the middle of the two Helmholtz peaks:



I'm convinced that a long-runner single plane manifold with runner diameters sized correctly for 5.0L engine would make more average power between the shift points than the S4 intake. In fact, Porsche made such a manifold for their S3 Group-B homologation efforts. A low quality photo of the manifold:



If you could cast a copy of this intake manifold sized for the 5.0L models such that stock MAF and airbox could be used, I think there would be a market for it. There might be enough people out there who aren't ever going to run big cams, headers, and ITBs but might want something little extra at the top end. But who knows.
ptuomov is online now  
Old 11-05-2017, 08:32 PM
  #779  
928sg
Resident 928 Modiholic
Rennlist Member
 
928sg's Avatar
 
Join Date: Mar 2013
Posts: 1,884
Default

Originally Posted by ptuomov View Post
I don't think that they took the most power out of the 32-valve models' intake manifolds.

I think they did the S4 manifold the way they did it because they needed a certain (large) amount of torque at very low rpms to create a single engine that's nice to drive with both automatic and manual transmissions.

The first iteration of the manifold was actually on the S3. They patented the true dual plan intake runner arrangement of S3 that has 40cm pipes (50cm total induction length) and equally-space pulses in each plenum. The S3 manifold produces the two Helmholtz tuning peaks.







The second iteration S4 added the second zip tube with the resonance flappy valve. They also made the manifold more compact, which lead to unequal length runners (four 20cm and four 30cm runners). The flappy open mode adds the torque peak in the middle of the two Helmholtz peaks:



I'm convinced that a long-runner single plane manifold with runner diameters sized correctly for 5.0L engine would make more average power between the shift points than the S4 intake. In fact, Porsche made such a manifold for their S3 Group-B homologation efforts. A low quality photo of the manifold:



If you could cast a copy of this intake manifold sized for the 5.0L models such that stock MAF and airbox could be used, I think there would be a market for it. There might be enough people out there who aren't ever going to run big cams, headers, and ITBs but might want something little extra at the top end. But who knows.
I think Greg Brown is making an intake manifold lik that last one but welded as it is cheaper to make them at low volume than a cast. Too bad someone doesn't make one out of plastic.
928sg is offline  
Old 11-05-2017, 08:43 PM
  #780  
Rob Edwards
Archive Gatekeeper
Rennlist Member
 
Rob Edwards's Avatar
 
Join Date: Sep 2002
Location: Irvine, CA
Posts: 13,637
Default

It was sorta like that , played very nicely on a 6.5: 50 hp and 40 torks.






And on a mildly massaged 5.0: 40 hp and 25 torks




Rob Edwards is offline  

Thread Tools
Search this Thread
Quick Reply: HIGHWAYMAN: Bringing the Devore 928 back from the dead


Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: