Short Stroke 2.8 - Page 3

camgrinder · 09-30-2005, 09:24 AM

About this time last year there was a post with a lot of good rod/stroke info..
http://forums.pelicanparts.com/showthread.php?threadid=184752

kenikh · 09-30-2005, 09:27 AM

Quote:

Originally posted by camgrinder
About this time last year there was a post with a lot of good rod/stroke info..
http://forums.pelicanparts.com/showthread.php?threadid=184752

Whoa...no kidding! Killer info.

blue72s · 10-01-2005, 09:24 AM

Quote:

Originally posted by Henry Schmidt
At 8500 this gets fuel yardage not mileage.
Joking aside, this engine like all other MFI engines is very thirsty.
I don't have any real fuel consumption numbers but I would guess 8-12 depending on right foot flexibility.

Henry, Why don't you test a Motronic fuel injection system (from 3.2 carrera) on your 2.8SS to see how it performs, and measure fuel mileage? (Can Motronic handle 8500rpm?)

Henry Schmidt · Henry Schmidt's Garage

I like MFI, always have, always will.
I'll leave the EFI engine development to those people who like it.
Fuel milaege does not interest me much.

" the fastest way to go broke in business is to get an ever growing percentage of an ever shrinking market"

Money must not be the primary motivation.

YTNUKLR · YTNUKLR's Garage

Henry, what did you set the deck height @ on the 2.8SS ?

Thanks, Scott

nabilious · 10-17-2005, 08:07 PM

Henry - howz about posting a link with some video and soundtrack to one of your creations!! I'm sure more than a few of us would like to meditate to that!
Nabil

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally posted by nabilious
Henry - howz about posting a link with some video and soundtrack to one of your creations!! I'm sure more than a few of us would like to meditate to that!
Nabil

Meditate? It sounds to me like pornography.

nabilious · 10-18-2005, 07:37 AM

We all have our weakness!!

speedingbullitt · 10-18-2005, 07:17 PM

Henry,

How would one differentiate between a 2.2 S crank and one from an E or T??

Thanks!

YTNUKLR · YTNUKLR's Garage

2.2S and E are the same.
pic:
http://forums.pelicanparts.com/showthread.php?threadid=240541

The 2.2T crank does not have counterweights, the flanges of dark metal that hang off opposite each journal. BTW, that one is still available.

Best regards, Scott

jluetjen · jluetjen's Garage

Wow! Cool thread. There's not much that I feel that I can add at this point.

Although I wonder if some of the difference in performance between short stroke and the long stroke 911ST motors might be due to the increase rod angularity that Henry describes above. On the other hand, one of the benefits of "longer" stroked motors that Porsche's designers have always appeared to have been sensitive to is that with a "longer" stroke motor it's possible to have a more compact combustion chamber (specifically, by this I mean that the surface area to volume ratio is smaller) which results in improved combustion, reduced emissions and reduced ignition timing for a given level of performance.

Just some unquantified thoughts.

blue72s · 10-19-2005, 12:58 PM

Quote:

Originally posted by YTNUKLR
Henry, what did you set the deck height @ on the 2.8SS ?

Thanks, Scott

Well?

Henry Schmidt · Henry Schmidt's Garage

.040 DECK HEIGHT
AND .070 VALVE TO PISTON CLEARANCE.
THIS IS THE SAME FOR ALL OUR HIGH PERFORMANCE ENGINE.
MOST ENGINE BUILDERS HAVE A SERIES OF NUMBERS THAT THEY ARE COMFORTABLE AND IN MY CASE THESE ARE THEM? THEY? IT? MINE

blue72s · 10-21-2005, 09:21 AM

Henry, I understand that you've used JE pistons for this application but is Mahle P&C's 95mm available for such a application? If so, what's the part #?

Henry Schmidt · Henry Schmidt's Garage

Mahle does not make a piston specifically designed for this engine configuration.
They do make a 10.5 to 1 compression, 3.0 RSR piston that you can order in a cylinder with SC bolt spacing that will work for a 2.8 SS engine. Part # from Andial is AND 10398495
Keep in mind that a 10.5 to 1, 3.0 piston was designed for a 70.4mm crank so when you install it on a 66mm crank you will loose static compression.
I have measured a loss from .5 to .58 reduction in comp. ratio when doing this conversion.
10.5 to 1 will now be as high as 10.0 to 1 and as low as 9.9 to 1.

With this engine as with all other engines of custom configuration, if compression ratio is important to you, you must measure it.

speedingbullitt · 10-21-2005, 10:45 AM

Henry Thanks for all the information!!

In your opinion is the mahle 3.0 RSR in which you listed the andial p/n for superior to the JE piston for longevity? Would you recommend the mahle over the JE? I am sure there is a big cost difference, but might there be any other reasons to use/ not use the mahle 3.0 RSR set?

Thanks again!

kenikh · 10-21-2005, 10:54 AM

What about Cosworth pistons in terms of longevity when compared to Mahle? Aren't Cosworth's about the same price?

blue72s · 10-21-2005, 10:54 AM

Quote:

Originally posted by Henry Schmidt
They do make a 10.5 to 1 compression, 3.0 RSR piston that you can order in a cylinder with SC bolt spacing that will work for a 2.8 SS engine. Part # from Andial is AND 10398495.

What its cylinder wall thickness?
Is it CE ring groove delete?

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally posted by blue72s
What its cylinder wall thickness?
Is it CE ring groove delete?

Cylinder wall thickness is stock for 95 mm SC or Carrera.
CE ring is optional. Either way.

Walt Fricke · 10-21-2005, 04:25 PM

[QUOTE]Originally posted by Henry Schmidt
[B] AFTER OVER A YEAR IT'S DONE

2.8 SHORT STROKE 66 MM STROKE 95 MM BORE

THIS BAD BOY SHOULD MAKE 300+ HORSE POWER AND TURN 8500 RPM

Henry - has this bad boy been on a dyno of some sort by now? Any numbers you can share?

Walt Fricke

(slowly building a similar engine with 3.2 heads and wondering particularly what cam to use, though my pistons are cut for more like 12/1 which might change things)