http://cgi.ebay.com/ebaymotors/Porsche-944-Porsche-944-Callaway-Turbo-951-C-300-HP-st
10-24-2005, 03:49 PM
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http://cgi.ebay.com/ebaymotors/Porsche-944-Porsche-944-Callaway-Turbo-951-C-300-HP-st
Pretty cool. Was not aware of this.
So the car was sent to Calloway or they worked in conjuction with Porsche??
So the car was sent to Calloway or they worked in conjuction with Porsche??
10-24-2005, 03:50 PM
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10-24-2005, 04:19 PM
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Reeves Callaway did the conversions in the early 1980s prior to the release of the 944T in the U.S. in 1986. Since this particular specimen has the sleeved block it appears to be original (Callaway put steel sleeves in to accommodate custom 8.0:1 pistons - bear in mind there were no 951 pistons available when they did this). I've chatted with the guy on IM - he seems pretty forthright although his asking price was a tad high when I did (maybe 2 months ago). Maybe he's become more reasonable (or desperate) since. . . I told him that as cool as the Callaway conversion cars are, they just don't command the market value one might think - I'd expect $6,000 to be about the market price for one in very good condition both cosmetically and mechanically.
That car's in reasonable shape (I'd have bought it if he wasn't so rigid on his price), but needs some TLC - the usual B.S. like cracked dash, seats, a/c doesn't work, paint is a little imperfect in areas, etc. etc. etc. I'd love to see someone on Rennlist get it; I've already PM-ed a couple people around here about it. . .
That car's in reasonable shape (I'd have bought it if he wasn't so rigid on his price), but needs some TLC - the usual B.S. like cracked dash, seats, a/c doesn't work, paint is a little imperfect in areas, etc. etc. etc. I'd love to see someone on Rennlist get it; I've already PM-ed a couple people around here about it. . .
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10-25-2005, 11:31 AM
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todd, yes the conversions Reeves Callaway did were (to my knowledge anyway) all to the early cars. The one I'm building right now is an early '85 and I suspect (although I have yet to confirm this) that it's one of the last 944 conversions he did based on a few things I've noticed (the manifold is a more advanced "split" design than the others I've seen to accommodate thermal expansion & contraction better, the manifold is slightly different, etc.) Anyway I've got a ton of information on these if you really want.
FWIW the sleeving was only to facilitate the use of 8.0:1 c/r pistons, which were only compatible with the steel cylinder walls, not alusil. I'm not 100% sure why this was done - possibly for cost (ever price out custom alusil-compatible pistons? That probably would have doubled the cost of the conversions!) There are steel-sleeved blocks that come available all the time and also I'm not certain that it was stamped in Callaway's own shop (remember, he was a start-up company in that era) - it might have been farmed out to a local machine shop or something. Either way, my understanding is that the sleeving on the engines he did is quite good.
It actually raises kind of an interesting question regarding authenticity versus availing onesself of new technology - I'm at a bit of an impasse regarding this decision on my own project. On the one hand, I'd like to use only what was available in the U.S. in 1985 for purposes of authenticity; on the other, I can either simply swap in 951 pistons to get the 8.0:1 c/r, or run standard n/a pistons (and their higher compression) with newer, more modern electronic controls and knock detection to prevent bad things from happening, although this wasn't an option in 1985. . . The block and pistons associated with whatever car originally had my Callaway components bolted to it have long since disappeared. Down the road I may well opt for a sleeved block with steel-compatible pistons which would make the conversion more authentic, but for now I'm fine with using a Porsche/Mahle solution - just not sure which one yet (higher or lower c/r).
Then there's the problem of the transmissions. . . The conversions Callaway did didn't do anything to the transmission - or the suspension - or the brakes. As such, an off-the-shelf 951 is going to be superior overall, but the power and simplicity of layout/design of the Callaway system make it superior, IMO. There's no stupid crossover pipe to contend with or cause oil pan gasket failures, the turbo spools VERY fast (IIRC full boost is made by 2,500 RPM), and it's matched very well to the 2.5L engine, making a healthy amount of power at only 12-15 psi. As with most things, it's a compromise. Currently I'm leaning towards incorporating what I consider the best points of Porsche's turbo solution and Callaway's to make something unique - e.g. use some form of water jacketing like Porsche did (Callaway's choice of the IHI-6B did not), use a stronger transmission / CVs and springs, retain the pass.-side placement of the turbo from the Callaway setup, run larger-capacity injectors from the 951 design with associated chip/fuel maps (also has the nice effect of freeing up the Callaway fifth & sixth injector ports for. . . well. . . "other" things. . .
, etc.)
If you want info. on the Callaway cars, I'd be happy to send you stuff as soon as I get my file server repaired (waiting on a new motherboard - BIOS died). I have literally dozens of pages of stuff, pics, etc.
FWIW the sleeving was only to facilitate the use of 8.0:1 c/r pistons, which were only compatible with the steel cylinder walls, not alusil. I'm not 100% sure why this was done - possibly for cost (ever price out custom alusil-compatible pistons? That probably would have doubled the cost of the conversions!) There are steel-sleeved blocks that come available all the time and also I'm not certain that it was stamped in Callaway's own shop (remember, he was a start-up company in that era) - it might have been farmed out to a local machine shop or something. Either way, my understanding is that the sleeving on the engines he did is quite good.
It actually raises kind of an interesting question regarding authenticity versus availing onesself of new technology - I'm at a bit of an impasse regarding this decision on my own project. On the one hand, I'd like to use only what was available in the U.S. in 1985 for purposes of authenticity; on the other, I can either simply swap in 951 pistons to get the 8.0:1 c/r, or run standard n/a pistons (and their higher compression) with newer, more modern electronic controls and knock detection to prevent bad things from happening, although this wasn't an option in 1985. . . The block and pistons associated with whatever car originally had my Callaway components bolted to it have long since disappeared. Down the road I may well opt for a sleeved block with steel-compatible pistons which would make the conversion more authentic, but for now I'm fine with using a Porsche/Mahle solution - just not sure which one yet (higher or lower c/r).
Then there's the problem of the transmissions. . . The conversions Callaway did didn't do anything to the transmission - or the suspension - or the brakes. As such, an off-the-shelf 951 is going to be superior overall, but the power and simplicity of layout/design of the Callaway system make it superior, IMO. There's no stupid crossover pipe to contend with or cause oil pan gasket failures, the turbo spools VERY fast (IIRC full boost is made by 2,500 RPM), and it's matched very well to the 2.5L engine, making a healthy amount of power at only 12-15 psi. As with most things, it's a compromise. Currently I'm leaning towards incorporating what I consider the best points of Porsche's turbo solution and Callaway's to make something unique - e.g. use some form of water jacketing like Porsche did (Callaway's choice of the IHI-6B did not), use a stronger transmission / CVs and springs, retain the pass.-side placement of the turbo from the Callaway setup, run larger-capacity injectors from the 951 design with associated chip/fuel maps (also has the nice effect of freeing up the Callaway fifth & sixth injector ports for. . . well. . . "other" things. . .
, etc.)If you want info. on the Callaway cars, I'd be happy to send you stuff as soon as I get my file server repaired (waiting on a new motherboard - BIOS died). I have literally dozens of pages of stuff, pics, etc.
10-26-2005, 11:41 AM
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Jeff,
Do you have any better photos of the exhuast manifolds on the Callaway? I've always been curious how they fitted up a hotside turbo and have never seen one up close. Thanks.
Do you have any better photos of the exhuast manifolds on the Callaway? I've always been curious how they fitted up a hotside turbo and have never seen one up close. Thanks.
10-26-2005, 01:56 PM
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I do have pics of mine but naturally they're on my currently inop. file server like all my other stuff. Hopefully my replacement motherboard will be here in a day or two and I can then get it up and going for you - I'll certainly post pics when I do (I love discussing this setup - can't you tell?)
For starters, check this:
http://members.rennlist.com/tholyoak...ion_parts.html
This guy has been on Rennlist (and Pelican), you can dig around his other pics to see the sleeving that Callaway did, as well as the pistons for lowered compression.
The only thing I don't like about the design is the 90-degree turns the exhaust gasses must make immediately after exiting the head - this probably limits flow at the upper end somewhat. As a "down the road" kind of modification, I've considered having the manifold custom modified (or simply getting another one fabricated) that uses a wedge-shaped chamber to make the path for the exhaust gasses more gradual, and to increase the volume immediately after the head to decrease pressure. FWIW the Callaway manifold addresses this somewhat, but I'd like to make it a bit more radical and get more of a back-facing angle to it.
This won't happen for some time though (I need to find a good welder that isn't going to charge me an arm & a leg for it). Something like this:
Basically cut away the rear 1/2 of the tubes coming off the head (the half that faces rearward) and weld in an angled tube that will make a wedge-shaped expansion chamber to reduce pressure (helps with flow) and make the turn a bit less radical.
First I gotta' get the car done with what I have though. . .
For starters, check this:
http://members.rennlist.com/tholyoak...ion_parts.html
This guy has been on Rennlist (and Pelican), you can dig around his other pics to see the sleeving that Callaway did, as well as the pistons for lowered compression.
The only thing I don't like about the design is the 90-degree turns the exhaust gasses must make immediately after exiting the head - this probably limits flow at the upper end somewhat. As a "down the road" kind of modification, I've considered having the manifold custom modified (or simply getting another one fabricated) that uses a wedge-shaped chamber to make the path for the exhaust gasses more gradual, and to increase the volume immediately after the head to decrease pressure. FWIW the Callaway manifold addresses this somewhat, but I'd like to make it a bit more radical and get more of a back-facing angle to it.
This won't happen for some time though (I need to find a good welder that isn't going to charge me an arm & a leg for it). Something like this:
Basically cut away the rear 1/2 of the tubes coming off the head (the half that faces rearward) and weld in an angled tube that will make a wedge-shaped expansion chamber to reduce pressure (helps with flow) and make the turn a bit less radical.
First I gotta' get the car done with what I have though. . .
10-26-2005, 08:54 PM
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what prevents the exhaust gases leaving one cylinder from going into another cylinder (or creating excess backpressure for exhaust gases leaving a cylinder) on the callaway manifold? i.e when cylinder one fires, then cylinder three, with such short runners wouldn't the exhaust gases from cyl. 3 have to fight the gases exiting from cyl. 1.....