 Building a 2.5ST, Anyone tried this? |
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| Hybrid_Teener |
 Jul 5 2006, 03:43 AM
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Member  Group: Members Posts: 98 Joined: 20-December 05 From: San Jose, CA/Saskatoon, SK Member No.: 5,301  |
"the 911 ST was made in tiny numbers. The cars were available with engines of either 2466 cc or 2492 cc, producing 270 bhp at 8000 rpm." ~Wikipedia
whaaaa??? that sounds awesome. I want one, cept that would probably be too expensive. Anyone build up their 2.4 to ST specs? Anyone _HAVE_ the 2.5ST specs at all??? I know they used lots of lightweight parts and stuff on the engine (to reduce parasidic drag etc i think..) but which parts? 280hp sounds sweet. k thanks ~Aaron |
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| Jeroen |
Jul 5 2006, 07:55 AM
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914 Guru Group: Members Posts: 7,887 Joined: 24-December 02 From: The Netherlands Member No.: 3 Region Association: Europe |
check the taildragger section of the bird-board
lots of info there... |
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| 914rat |
Jul 5 2006, 05:16 PM
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Member Group: Members Posts: 279 Joined: 3-July 06 From: Maryland Member No.: 6,362 |
QUOTE(Hybrid_Teener @ Jul 5 2006, 01:43 AM)  "the 911 ST was made in tiny numbers. The cars were available with engines of either 2466 cc or 2492 cc, producing 270 bhp at 8000 rpm." ~Wikipedia whaaaa??? that sounds awesome. I want one, cept that would probably be too expensive. Anyone build up their 2.4 to ST specs? Anyone _HAVE_ the 2.5ST specs at all??? I know they used lots of lightweight parts and stuff on the engine (to reduce parasidic drag etc i think..) but which parts? 280hp sounds sweet. k thanks ~Aaron I think I remember reading about that in Dave Andersons book on 911 performance.It would be way to costly to buy or build.I think I'll have a V8 instead. |
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| TravisNeff |
Jul 5 2006, 05:20 PM
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#4
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914 Guru Group: Members Posts: 5,082 Joined: 20-March 03 From: Mesa, AZ Member No.: 447 Region Association: Southwest Region 
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Eric Shea and Michal Richard are both building 2.5 short stroke engines for their teeners.
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| Trekkor |
Jul 5 2006, 05:46 PM
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#5
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I do things... Group: Members Posts: 7,809 Joined: 2-December 03 From: Napa, Ca Member No.: 1,413 Region Association: Northern California |
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| lapuwali |
Jul 5 2006, 05:56 PM
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#6
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Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743  |
A 2.5 short stroke wouldn't be all that expensive (relatively speaking). A 2.0 or 2.2 starter engine (66mm crank) with 90mm cylinders (stock diameter for the 2.7, so commonly available) plus 90mm pistons (NOT 2.7 CIS parts) and cams will get you there. You'd need full PEFI or carbs to get that kind of power, and it would require a lot of revs to get 250+hp. I doubt a short-stroke 2.5 would be a very good AX engine, as you'd be shifting a lot to keep it in the powerband. It would likely be a nice track engine, though.
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| TimT |
Jul 5 2006, 06:46 PM
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retired Group: Members Posts: 4,033 Joined: 18-February 03 From: Wantagh, NY Member No.: 313 |
one of the problems with using the 2.7 p/c to make a 2.5 on a short stroke crank is that the compression ratio will end up being rather low. I think in the 8:1 or less range.
You could buy just the 2.7 jugs, and then have a set of JE or Omega or Arias etc pistons made to make a compression ratio of greater than 9.5: or so. Now that would be a sweet engine. |
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| Van914 |
Jul 6 2006, 03:39 AM
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#8
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Van914 Group: Members Posts: 698 Joined: 5-January 03 From: Cincinnati, Ohio Member No.: 90 Region Association: Upper MidWest
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Here is one for sale on the Bird Board. I would like this for the track but street and auto-x I would prefer a little more torque.
van914 2.5 Short Stroke FS |
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| ChicagoPete |
Jul 6 2006, 11:47 AM
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#9
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Member Group: Members Posts: 227 Joined: 10-January 05 From: Lake Forest,IL Member No.: 3,427 |
Real parts for a true 2.5 ST motor are very rare...and expensive
86.7mm Mahle p/c(10.3:1) and 70.4mm stroke...2492cc 270hp@8000rpm 87.5mm Mahle p/c(10.3:1) and 66mm stroke...2380cc 230hp@7800rpm Very, Very rare and expensive p/c to find..not to mention the heads... Build a 2.6L short stroke...92mm p/c with 66mm, that motor is a screamer. Heads need quite a bit of work with the RSR pistons...unless you use something like JE pistons...far cheaper alternative than Mahle stuff |
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| redshift |
Jul 6 2006, 11:53 AM
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Bless the Hell out of you! Group: Members Posts: 10,926 Joined: 29-June 03 Member No.: 869 |
When mentioning Eric Shea, never forget to placcard it with "the crazy guy".
M |
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| TravisNeff |
Jul 6 2006, 12:06 PM
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#11
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914 Guru Group: Members Posts: 5,082 Joined: 20-March 03 From: Mesa, AZ Member No.: 447 Region Association: Southwest Region
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It was implied (IMG:style_emoticons/default/laugh.gif)
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| Brett W |
Jul 6 2006, 04:43 PM
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#12
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Advanced Member Group: Members Posts: 2,856 Joined: 17-September 03 From: huntsville, al Member No.: 1,169 Region Association: None
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How similar is the 993 engine to the early stuff. Could you take the crank from an early motor and combine it with the better cylinders and heads from a 993 engine? That would be a great motor. Lots of revs and much better heads than the early stuff.
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| Al Meredith |
Jul 6 2006, 08:20 PM
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#13
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Senior Member Group: Members Posts: 960 Joined: 4-November 04 From: Atlanta, ga Member No.: 3,061 |
About two yease ago I bought a 2.4L T engine that was running 10 years ago "when we put it up"said the PO. My son installed it in a 914 and it started right up (we used carbs). Pulled 160HP at the wheels ....not a "t" which is 140HP at the crank.We decided to rebuild it anywhy. It had 87.5 MM bore and stock 2.4 crank. The rods were polished and the case was "rounded". The flywheel was very light.
Two of the cylinders were broken at the very top allowing blow by under the casket. Just finished assembling (fired up nicely) Had to go to LN engineering for a custom set of nickies because we wanted to stay with the unique 87.5MM pistons. Everything was redone or replaced, including case work by CE. Been to the dyno to pull a couple of hard pulls for breakin. I think it got to 170 HP at 5000 RPM with just points and a blue coil..no spark box. Once dialed in we are lookin for 200 HP at the wheels ; maybe 223 +/- at the crank. We will keep the board advised as we progress. Al |
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