Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 Engine Rebuilding Forum


Reply
 
LinkBack Thread Tools Rating: Thread Rating: 2 votes, 5.00 average.
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Nov 2005
Location: Los Angeles
Posts: 494
Henry, thank you for that. That's helpful.

I didn't intend to build a 2.8SS on a 2.7. As I said, the 2.8SS is a new possibility to me, and it's VERY interesting. I have a 2.7RS now, I love it, and have become a huge MFI fan.

Whether I build this new motor on a 2.7 or a 3.0 turbo case is an easy choice since I don't own a second engine yet, and I don't intend to use my existing 2.7 as the core. The idea is to find a core whenever a good opportunity arises, and slowly collect parts, and then slowly build a new high performance motor which would eventually replace the one I have now. If it takes three years to get it done, fine.

A couple more questions if you don't mind.

One thing that appeals about the 2.8S is its longevity, especially if one keeps the revs down. In other threads, Grady and Steve W. have both attested to its durability and power, suggesting a safe 275-280hp is reasonable, without having to refresh every 25-50 hours. It could function in a street car as well as a track/racing car.

How does the 2.8SS compare in that regard? How often would it require refreshing? And if one were to keep the revs limited at or below say 8,000, would that substantially increase the longevity of the motor--or would you just be defeating the point of the engine in the first place by keeping it out of the high end of its usable power band?

The bottom line for me is this: as much as it's far more economical to buy a stock(ish) 3.6, or lightly built 3.2, my ideal dream motor would be a reliable, 300 hp, twin plug MFI race or near-race engine, with super sharp throttle response, a knee-buckling sound, and something sweet to look at. I don't care about fuel economy in this case. Whatever gets me to that goal is where I'll go, be it a 2.8SS or 2.8S, or 2.8RSR or 3.0RSR.
__________________
1974 911 Carrera 2.7RS+
1968 912 -- sold
2007 S2000
2004 R32 -- for sale; inquire within!
1990 Ford Ranger prerunner
Old 10-29-2006, 09:04 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #81 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
Quote:
Originally posted by pieterk
Henry, thank you for that. That's helpful.

I didn't intend to build a 2.8SS on a 2.7. As I said, the 2.8SS is a new possibility to me, and it's VERY interesting. I have a 2.7RS now, I love it, and have become a huge MFI fan.

Whether I build this new motor on a 2.7 or a 3.0 turbo case is an easy choice since I don't own a second engine yet, and I don't intend to use my existing 2.7 as the core. The idea is to find a core whenever a good opportunity arises, and slowly collect parts, and then slowly build a new high performance motor which would eventually replace the one I have now. If it takes three years to get it done, fine.

A couple more questions if you don't mind.

One thing that appeals about the 2.8S is its longevity, especially if one keeps the revs down. In other threads, Grady and Steve W. have both attested to its durability and power, suggesting a safe 275-280hp is reasonable, without having to refresh every 25-50 hours. It could function in a street car as well as a track/racing car.

How does the 2.8SS compare in that regard? How often would it require refreshing? And if one were to keep the revs limited at or below say 8,000, would that substantially increase the longevity of the motor--or would you just be defeating the point of the engine in the first place by keeping it out of the high end of its usable power band?

The bottom line for me is this: as much as it's far more economical to buy a stock(ish) 3.6, or lightly built 3.2, my ideal dream motor would be a reliable, 300 hp, twin plug MFI race or near-race engine, with super sharp throttle response, a knee-buckling sound, and something sweet to look at. I don't care about fuel economy in this case. Whatever gets me to that goal is where I'll go, be it a 2.8SS or 2.8S, or 2.8RSR or 3.0RSR.
A 2.8 SS should by design out live other 2.8 configurations.
300 horse power is doable and longevity is strictly a function of RPM. There is no reason why a 2.8SS shouldn't last 100K miles if trips to 8000 are few and far between.
For what you are desiring I would guess that a 3.2 SS MFI would be more sensible. Good torque, 7600 red line and and the look feel and sound of the racing RSR.

__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 10-29-2006, 09:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #82 (permalink)
Registered User
 
North Coast Cab's Avatar
 
Join Date: Sep 2002
Location: Cleveland
Posts: 4,422
Garage
Henry,
Could you describe in more detail what you think a 3.2SS would be made of?

TIA, John
__________________
1985.5 944 GTS
Old 10-29-2006, 01:33 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #83 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
The engine consist of :
SC, Carrera or 3.3 case.
3.0 (70.4) crank,
3.0, 3.2 or 3.3 heads. (3.2 are the least desirable because of over sized ports and short flanges)
SC rods with ARP bolts (Carrillos if the budget allows)
98 mm pistons and cylinders
Cams to suit your expectations. ( DC 60, 62 or 80 ?)
Supertec twin plug distributor
MFI pump to suit
Throttle bodies 40 X 41.5
Stacks 41.5 x 50 mm
PMO Velocity stacks and air filters.
Quality oil pump (mod SC or larger)
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 10-29-2006, 02:41 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #84 (permalink)
Registered User
 
Join Date: Jan 2003
Location: Burlington, Wisconsin
Posts: 9,416
wow looks great henry. I can't wait to get all my parts together to start to build the 3.2 ss turbo
__________________
Ben

914-6 2.4s GT tribute.
914-6werkshop.com manufacturer of 914-6, GT, Conversion parts
Old 10-29-2006, 03:11 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #85 (permalink)
Registered User
 
911 tweaks's Avatar
 
Join Date: Apr 2006
Location: northeast
Posts: 3,941
Henry,
Based on the 3.2SS you described, what would be the hp made??

Basically, is the 3.2SS the next logical step "up" in HP vs. the 2.8SS??

Would this set up benefit with the 66mm crank??
__________________
I live for 911 tweaks...
Old 10-29-2006, 05:06 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #86 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
Cams and compression will determine ultimate performance but with 10.5 :1 and DC62 cams I would predict 320 at 6900-7100 and 280 + ft/lb.



Would this set up benefit with the 66mm crank??
If revving the engine to 8000+ is important to you.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net

Last edited by Henry Schmidt; 10-29-2006 at 05:26 PM..
Old 10-29-2006, 05:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #87 (permalink)
Registered User
 
Join Date: Jul 2003
Posts: 721
Have you ever thought about fitting 4 valve watercooled heads on these engines? Can 4 valve heads fit on SC case?
Old 10-29-2006, 05:35 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #88 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
In theory, GTR3 RSR heads should fit. 962 water cooled heads should also fit. Just guessing. You guys with later model experience will have to chime in.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 10-29-2006, 05:42 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #89 (permalink)
Gon fix it with me hammer
 
svandamme's Avatar
 
Join Date: Sep 2003
Location: In Flanders Fields where the poppies blow
Posts: 18,710
Garage
bump , does anybody know what how much work it is to mod SC heads to take MFI injectors?? according to PET, SC's have injectors in the intake runners, not in the heads??
__________________
Stijn Vandamme
EX911STARGA73EX92477EX94484EX944S88NOW987C2007
Old 03-05-2007, 04:59 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #90 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
I simple three step machine process is all that is necessary.

Most shops familiar with this process should be able to perform the service for as little as $180.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 03-05-2007, 05:25 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #91 (permalink)
Gon fix it with me hammer
 
svandamme's Avatar
 
Join Date: Sep 2003
Location: In Flanders Fields where the poppies blow
Posts: 18,710
Garage
thanks for that !
__________________
Stijn Vandamme
EX911STARGA73EX92477EX94484EX944S88NOW987C2007
Old 03-05-2007, 05:30 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #92 (permalink)
Registered User
 
Walt Fricke's Avatar
 
Join Date: May 2004
Location: Boulder, Colorado
Posts: 5,233
Porsche Crest 3.2 heads for SS

I have a set of 3.2 heads to use on my SS 2.8 project. Port sizes seem about right as they are. But I have two questions:

1) The intake ports are not round at the top, to make way for the injectors. There is an indentation. I'm going to use carbs. Should I consider having this area welded and then machined? Some other way of returning them to a cylindrical shape? Because otherwise it will leave a pocket below the carburetor intake manifold.

2) I'm most likely going to run SC cylinders, with the CE rings. But the 3.2s didn't use sealing rings - something was slightly tapered. Was it the head sealing surface, and if so do I need to do something about that or is it OK as is for use with CE rings and stock SC cylinders?

Walt Fricke
Old 03-05-2007, 02:33 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #93 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
The heads are fine. Just order the PMO manifolds that are designed for this application.

The heads are flat, the cylinders have a slight taper. The SC cylinders will work fine.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net

Last edited by Henry Schmidt; 03-05-2007 at 03:13 PM..
Old 03-05-2007, 03:06 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #94 (permalink)
Gon fix it with me hammer
 
svandamme's Avatar
 
Join Date: Sep 2003
Location: In Flanders Fields where the poppies blow
Posts: 18,710
Garage
Henri,

i have 3.2 Heads laying around from a 3.2 junker i bought
they seem perfectly good heads
you mentioned earlier , that those are to big?

what's the drawback of using bigger 3.2 heads??
can't get too much air in there no?

i'm not aiming at the full 300 hp 2.8SS, i'm not that good of a driver, and i want to keep it streetable,but more like a slightly beefed up 2.7RS, 240 maybe 250 HP

you think those 3.2 heads are good for?
__________________
Stijn Vandamme
EX911STARGA73EX92477EX94484EX944S88NOW987C2007
Old 03-05-2007, 11:17 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #95 (permalink)
Try not, Do or Do not
 
Henry Schmidt's Avatar
 
Join Date: Apr 2004
Location: Fallbrook, Ca. 92028
Posts: 6,028
Garage
I believe that the 41.5 mm intake port on the 3.2 head is too large to promote good port velocity.
High port velocity is necessary for maximum volumetric efficiency.
Port shape and size not just port size is important for engine performance.
Bigger is better only in a full throttle situation. must engines don't run full pedal all the time.
I would recommend a maximum 40 mm port for a 2.8 SS with an intake manifold of 38 mm. This lip at the transition will assist in the control of intake pulses caused by cam overlap and is exaggerated by large duration cams.

Big ports = poor low end possible good high end
small port = good low end possible reduced high end throttle response

Calculate CFM for your projected max RPM and run the smallest port to accomplish that volume.

With a 2.8 @ 7600 RPM 38 mm manifold is appropriate. Add 2 mm to the port for pulse control and you win.

8500 race on a race engine with proper gearing and bigger is better.
__________________
Henry Schmidt
SUPERTEC PERFORMANCE
Ph: 760-728-3062
Email: supertec1@earthlink.net
Old 03-06-2007, 06:02 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #96 (permalink)
Gon fix it with me hammer
 
svandamme's Avatar
 
Join Date: Sep 2003
Location: In Flanders Fields where the poppies blow
Posts: 18,710
Garage
that'll definately do for explanation

also understand now, how MFI Throttle bodies work on bigger engines , cause i always wondered how that worked , since you can't bore the TB's to big...


38 mm is exactly the size of the TB's, at least the top part ( T TB's) so all that is needed now, is to bore out the lower part below the valve, which shouldn't be a big problem ...

thx again Henri , you're a star !
__________________
Stijn Vandamme
EX911STARGA73EX92477EX94484EX944S88NOW987C2007
Old 03-06-2007, 06:07 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #97 (permalink)
Registered User
 
Jeff Alton's Avatar
 
Join Date: Jan 2003
Location: Langley,B.C.
Posts: 10,255
Walt, I ran into the same problem when putting my Jenveys onto my 3.2 heads (3.4)

I used the PMO insulator/spacer kit as it took care of the problem, so once again Henry knows of what he speaks!!

You will be fine with the PMO kit!

Cheers
__________________
Turn3 Autosport- Full Service and Race Prep
jeff@turn3autosport.com
997 S 4.0, Cayman S 3.8, Boxster 2.7, Boxster S race car, 996, 955 Cayenne TT, 958 Cayenne TT
Old 03-06-2007, 08:49 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #98 (permalink)
 
Registered User
 
Walt Fricke's Avatar
 
Join Date: May 2004
Location: Boulder, Colorado
Posts: 5,233
Porsche Crest

Jeff

Does the PMO insulator/spacer kit take care of this problem (if it is a problem)? How?

"1) The intake ports are not round at the top, to make way for the injectors. There is an indentation. I'm going to use carbs. Should I consider having this area welded and then machined? Some other way of returning them to a cylindrical shape? Because otherwise it will leave a pocket below the carburetor intake manifold."

I used their kit for my 2.7 race motor with 38mm intake port heads, but as I recall boring the ports out from 35mm or whatever they were took care of the CIS injector pocket. But the 3.2 heads are big enough as they are for my SS race motor, so unless I do anything that pocket will be there. Sitting below a 41.5mm PMO tall intake runner and the insulators and gaskets that go with it.

Maybe that is not a problem - a kind of partial anti-reversion step? I'm a bit dubious about such serendipity.

And thank you, Henry, for telling me what was beveled. When one is basically an engine assembler rather than a real builder, this is really appreciated.

Walt Fricke
Old 03-06-2007, 10:10 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #99 (permalink)
Registered User
 
Jeff Alton's Avatar
 
Join Date: Jan 2003
Location: Langley,B.C.
Posts: 10,255
Walt,

The insulator and associated gaskets cover over the cut out for the injector. I guess there there is still a small recess inside the port once you cover it up, but it is sealed at least. I can't think of another bolt on way to fix this problem.

Cheers
__________________
Turn3 Autosport- Full Service and Race Prep
jeff@turn3autosport.com
997 S 4.0, Cayman S 3.8, Boxster 2.7, Boxster S race car, 996, 955 Cayenne TT, 958 Cayenne TT
Old 03-07-2007, 07:43 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #100 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 06:54 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.