964 C2 3.8 Build Thread
03-15-2017, 09:12 PM
#46
Hi Bill -
- At the time I was collecting bits and pieces for this C4 project, and I had thought that the RS DME would be a shortcut to a faster tune. After the dyno work I think the mapping was customized anyway from that base.
- The data is flywheel. The car was over there, and the engine over here.
- At the time I was collecting bits and pieces for this C4 project, and I had thought that the RS DME would be a shortcut to a faster tune. After the dyno work I think the mapping was customized anyway from that base.
- The data is flywheel. The car was over there, and the engine over here.
The dyno shows pretty much what we've seen on typical 3.8 rebuilds, the most noticeable thing over stock is the increased torque across the board, makes for a much more pleasant driving experience.
03-16-2017, 01:18 AM
#47
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
03-16-2017, 07:23 PM
#48
what Juha was asking about was the cylinder base
There are 2 sizes of base spiggot
stock is 107mm
slip fit 102mm bore cylinders use this same size hole.
The more robust 102mm bore cylinders used in RSR have 109mm spiggots.
The bigger bores provide a more stable distortion free platform also are a great place to store empty soda bottles
This is a 109mm RSR cylinder note the large groove in the spiggot, there is a matching groove in the block for a more robust gasket than that used on a stock 3.6
Other differences are the coated piston skirts and tapered wrist pin, neither are used in a 3.6 or the 107mm base p/c sets I've seen.
There are 2 sizes of base spiggot
stock is 107mm
slip fit 102mm bore cylinders use this same size hole.
The more robust 102mm bore cylinders used in RSR have 109mm spiggots.
The bigger bores provide a more stable distortion free platform also are a great place to store empty soda bottles
This is a 109mm RSR cylinder note the large groove in the spiggot, there is a matching groove in the block for a more robust gasket than that used on a stock 3.6
Other differences are the coated piston skirts and tapered wrist pin, neither are used in a 3.6 or the 107mm base p/c sets I've seen.
03-16-2017, 10:17 PM
#50
Rennlist Member
Thread Starter
Making headway ... Tim Olsen is making sure sunroof delete and paint are done right. Have to decide color by next week. Hardest part of process for me. Wish I knew the actual code of the gray 911 that I saw last summer in Geneva. That car had a gun metal exterior with a linen interior and I believe it was an 87 or 88.
03-17-2017, 11:08 AM
#51
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Hi Ed
I had a similar bit of work done by George at Eurosport Racing in 2010 (time flies!) on my '91 964.
3.8 Mahle p/c, ARP bolts, ported head, 993 RS valves, Ti retainers, custom cam ... trans rebuild w a few new synchros, LWFW, RS clutch, JRZ ... I'm sure I'm forgetting some things.
I put on the Fabspeed exhaust w/heat. Great sound, and a modest drone that went away with time. I don't get enough heat from those small sized heat exchangers to drive in the winter in Chicago.
I also sourced a 964 Euro RS ECU. I recall George did some extra dyno work and replacing the pressure regulator to maximize that benefit.
The car is at Autobahn in Joliet if you'd like to see it or give it a listen/drive when next you're down there.
Can't say enough good things about George and his team, as I'm sure you know. You're in good hands.
Dyno results attached ... YhpMV ... I'm sure you'll love it
Best,
Ez
I had a similar bit of work done by George at Eurosport Racing in 2010 (time flies!) on my '91 964.
3.8 Mahle p/c, ARP bolts, ported head, 993 RS valves, Ti retainers, custom cam ... trans rebuild w a few new synchros, LWFW, RS clutch, JRZ ... I'm sure I'm forgetting some things.
I put on the Fabspeed exhaust w/heat. Great sound, and a modest drone that went away with time. I don't get enough heat from those small sized heat exchangers to drive in the winter in Chicago.
I also sourced a 964 Euro RS ECU. I recall George did some extra dyno work and replacing the pressure regulator to maximize that benefit.
The car is at Autobahn in Joliet if you'd like to see it or give it a listen/drive when next you're down there.
Can't say enough good things about George and his team, as I'm sure you know. You're in good hands.
Dyno results attached ... YhpMV ... I'm sure you'll love it
Best,
Ez
__________________
Porsche Performance Specialist
John@Fabspeed.com
215-618-9796
Fabspeed Motorsport USA
155 Commerce Drive Fort Washington, PA 19034
www.Fabspeed.com
Porsche Performance Specialist
John@Fabspeed.com
215-618-9796
Fabspeed Motorsport USA
155 Commerce Drive Fort Washington, PA 19034
www.Fabspeed.com
03-17-2017, 03:52 PM
#52
I wonder how much of the "increased strength" of a bore in cylinder, is actually verified by testing vs hypothetical. Also, the clamping loads are between the top of the cylinder and the base that mounts to the outside surface of the crankcase aren't they? Does the spigot carry a clamping load? Is the spigot in a bore in cylinder a tighter fit in the crankcase?
03-17-2017, 07:27 PM
#53
Interesting, does this mean the larger spigot that requires the crankcase be bored out, has a groove that negates some of the increased size? And also requires a weakening groove in the crankcase?
I wonder how much of the "increased strength" of a bore in cylinder, is actually verified by testing vs hypothetical. Also, the clamping loads are between the top of the cylinder and the base that mounts to the outside surface of the crankcase aren't they? Does the spigot carry a clamping load? Is the spigot in a bore in cylinder a tighter fit in the crankcase?
I wonder how much of the "increased strength" of a bore in cylinder, is actually verified by testing vs hypothetical. Also, the clamping loads are between the top of the cylinder and the base that mounts to the outside surface of the crankcase aren't they? Does the spigot carry a clamping load? Is the spigot in a bore in cylinder a tighter fit in the crankcase?
The 102mm x 109mm bore cylinders are more stable than the 102mm x 107mm versions
the profile groove in the case does not weaken the case in any way either.
the 107mm base cylinders use a 102 x 2mm o-ring
the 109mm base cylinders use a 110.72 x 3.53mm o-ring
the larger gasket better seals the cc, thesis is desirable due to the larger volumes of air moved around by the 102mm pistons compared to 100mm stock pistons. A further addition is to use a cc vacuum vent valve that lowers cc operating pressure. This additionally involves using modified crankshaft seals and was standard on the later GT3 models.
03-18-2017, 12:57 AM
#54
The part of the cylinder that is loaded, i.e. the part outside the case, is not any smaller in the slip fit versions. So how much more "stable" is the bore in version, and what exactly is the measurement of "stable". I want real facts, not opinions, I want a quantifiable number. It's not a hard question. Without a number, it is impossible to determine if one version is "better", especially when trying to determine if it is worth the cost. Are the companies selling slip fit cylinders peddling 100% junk, or are they selling an alternative that is 1% weaker. Is it weaker in a portion of the cylinder where the loads are lowest? Does it matter?
03-18-2017, 09:36 AM
#55
The part of the cylinder that is loaded, i.e. the part outside the case, is not any smaller in the slip fit versions. So how much more "stable" is the bore in version, and what exactly is the measurement of "stable". I want real facts, not opinions, I want a quantifiable number. It's not a hard question. Without a number, it is impossible to determine if one version is "better", especially when trying to determine if it is worth the cost. Are the companies selling slip fit cylinders peddling 100% junk, or are they selling an alternative that is 1% weaker. Is it weaker in a portion of the cylinder where the loads are lowest? Does it matter?
All mechanical components distort when in use the degree varies the metrics are proprietary and will not be published any where. Take a lesson from the factory builds and 20yrs of experience w/ subsequent rebuilds.
tenths of mm matter as do tenths of g.
03-18-2017, 09:56 AM
#56
For street use it won't matter, for racing it does, for typical modern DE use it does.
All mechanical components distort when in use the degree varies the metrics are proprietary and will not be published any where. Take a lesson from the factory builds and 20yrs of experience w/ subsequent rebuilds.
tenths of mm matter as do tenths of g.
All mechanical components distort when in use the degree varies the metrics are proprietary and will not be published any where. Take a lesson from the factory builds and 20yrs of experience w/ subsequent rebuilds.
tenths of mm matter as do tenths of g.
Someday I'm going to be in the market for a new P&C set, and I would love to see real data from one of the manufacturers of big bore cylinders. A real instability would show itself on the dyno, or with miles. As it is, we have notable engine builders comment about failures with no info as to the usage, certainly not any controlled usage. Was it overheated, extremely high rpm, etc, we don't know.
03-18-2017, 05:56 PM
#57
Rennlist Member
Sorry if I sounded like a smart ***, but I am used to a racing and engineering world where the plural of anecdote isn't data. Even the hot rod world has reams of dyno data on every combo immaginary. In porscheland, everyone relies on what the mothership did 25+ years ago when they were almost broke.
Someday I'm going to be in the market for a new P&C set, and I would love to see real data from one of the manufacturers of big bore cylinders. A real instability would show itself on the dyno, or with miles. As it is, we have notable engine builders comment about failures with no info as to the usage, certainly not any controlled usage. Was it overheated, extremely high rpm, etc, we don't know.
Someday I'm going to be in the market for a new P&C set, and I would love to see real data from one of the manufacturers of big bore cylinders. A real instability would show itself on the dyno, or with miles. As it is, we have notable engine builders comment about failures with no info as to the usage, certainly not any controlled usage. Was it overheated, extremely high rpm, etc, we don't know.
The bolded part represents everything that Porsche has always been to me. Take any stock air cooled Porsche that is taken care off, fill up the tank and hit the autobahn until you run out of gas. No matter wether it is a 265hp Carrera or a 430hp GT2, it will do anything you ask from it and then some.
Porsche doesn't make engines like that anymore...they do make profit. I suppose it's difficult (if not impossible) to do both.
As for the slip-in vs. bore in; for me the difference in cost was just too insignificant in a 25k eur rebuild to even consider the slip in version. In for a penny, in for a pound...
04-11-2017, 06:27 PM
#58
Rennlist Member
Thread Starter
Bare metal in progress ... single stage fashion gray (H61) going on the underside.
Rendition of car with HRE wheels.
Sunroof delete completed with Fenn Lane panel and Upol filler as recommended by Chris. Body shop couldn't believe how solid Upol was when dried. They had not used that product before.
I got lucky with a rust free car from California. Had two spots on the lower windshield under the gasket in the usual spots.
Rendition of car with HRE wheels.
Sunroof delete completed with Fenn Lane panel and Upol filler as recommended by Chris. Body shop couldn't believe how solid Upol was when dried. They had not used that product before.
I got lucky with a rust free car from California. Had two spots on the lower windshield under the gasket in the usual spots.
