Purchase of a 968
07-04-2012, 09:17 PM
#16
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addicted to V8's....
realistically, the moment you step away from the oem 3.0 platform you're in a world of hurt. i like Corvettes, but i like the looks of your 968s better..... i'm gonna confess, i also like that there's no (middle aged fat guy) stigma attached to the 968....
in terms of performance, the differenence isn't all that much. it's more of a question of philosophy; all-Porsche vs frankencar Porsche.... and for a lot of people that's a hard one.... but the difference between a 3.0 968 running a turbine and a Corvette isn't earthshattering.... (as they're both, quick, 3,100 pound transaxle cars). they corner very similar.... but, an LSx 968 or Corvette offers way more torque and power (at the moment you shift up into the next gear). with the parts we have available, the best equipped 968 transmission drops from about *(6,200 rpm down to 4,300).... this isn't ideal for the Turbo S. it would do better with a 7-speed transmission or an original Turbo S box.... but running the V8, with either car, the 1,900~2,000 rpm drop still leaves you in the junior-hypercar club, as the Chevy is making peak torque in the low 4,000s....
the other issue with the turbo, is the cost to daily drive one for 100 k miles. you're in seriously huge money keeping that Turbo replica tuned. not sure most of the new-to-the-4-cylinder guys really get the full brunt of what i'm talking about here.... regardless of whatever you're running, there are parts of the 968 that require updates, but you're a lot better off doing simple oil changes, and valvespring replacements with the V8 than you would be turbocharging a 3.0, and tuning one..... in the time one guy is replacing 2 pairs of valvesprings, and a timing chain, a guy running a 3.0 turbo could easily top $100 K (running completely through a pair of engines and be getting started on his third).... wait. did i hear you correctly ? 2 engines to go 100 k miles ? absolutely. so i'll pay my $30 k plus the cost of the transmission, and expect to go 200 k miles before tearing down the engine.
* the 3.4 R&P (unobtanium) in the stock Turbo S transmission produces a less severe drop.
07-06-2012, 01:51 PM
#17
Burning Brakes
Why would a turbocharged 968 engine (assuming the proper precations were taken) have such a short life? I had a very experienced machine shop measure the bore diameters of my block when I had it torn down (115K miles, lots of track day use), and they concluded there was virtually zero wear. In fact, the machinist (the owner of the shop) commented that the block should go a million miles. With an o-ringed head, racing-grade head and crank cradle studs, a pinned cradle, upgraded connecting rods, etc., I would think a turbocharged version of this engine could have a long and trouble-free life, although I have zero personal experience with this. But the fact that turbo 944 engines have been around so long, many of them in race cars, makes me think there should be plenty of experience with making these engines last under boost. Is there some component that's unique to the 3.0 liter engine that makes them prone to self-destruction when a turbo is slapped on?
07-06-2012, 03:26 PM
#18
Rennlist Member
As you might know Allan owns a 968 turbo and that is why he knows so much about the cost of ownership :P
He also happens to be on someone's payroll to promote V8 conversions j/k
He also happens to be on someone's payroll to promote V8 conversions j/k
07-06-2012, 03:38 PM
#19
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i know it's utter blasphemy to say it in these circles.....
Why would a turbocharged 968 engine (assuming the proper precations were taken) have such a short life? I had a very experienced machine shop measure the bore diameters of my block when I had it torn down (115K miles, lots of track day use), and they concluded there was virtually zero wear. In fact, the machinist (the owner of the shop) commented that the block should go a million miles. With an o-ringed head, racing-grade head and crank cradle studs, a pinned cradle, upgraded connecting rods, etc., I would think a turbocharged version of this engine could have a long and trouble-free life, although I have zero personal experience with this. But the fact that turbo 944 engines have been around so long, many of them in race cars, makes me think there should be plenty of experience with making these engines last under boost. Is there some component that's unique to the 3.0 liter engine that makes them prone to self-destruction when a turbo is slapped on?
i'm not going to make a lot of friends saying it, and this in no-way, is a reflection of how little or much i admire what people do to live the P-car turbo experience... and i haven't had the pleasure of owning one of these, but after reading two hundred dead-turbo, personal-bankrupcy threads on RL dating back about 5 years, i'm in the LESS-THAN-50,000-mile believer club (reflexive; dozens of examples of better and worse) i'm not the more than club. can the 968 Turbo be driven daily ? sure.... in much the same fashion that you can dedicate yourself to dating strippers and **** stars. you can do it, but you better be prepared to pay. driving a Turbo S replica in no way/shape/or form resembles the driving experience associated with a muscle-car engine. the 968 Turbo engine is a life-on-the-edge, low-level exotic, requiring the scale of care and expectation of consequences that you would normally associate with other exotics.... replacing timing belts (and associated parts), H20 pumps, rod-bearings, turbine related items, head gaskets, seals, oil cooler lines etc, and tuning are just part of what goes along with a 100,000 mile 968 Turbo driving experience. you can do it, but if you're not doing it yourself, you'll be paying someone else a significant quantity of cash to get to 100,000 miles and beyond of spirited driving with a proper running car.
.
Last edited by odurandina; 07-06-2012 at 04:47 PM.
07-06-2012, 04:03 PM
#20
Rennlist Member
i'm not going to make a lot of friends saying it, and this in no-way, is a reflection of how much or less i admire what people do to live the P-car turbo experience... and i haven't had the pleasure of owning one of these, but after reading two hundred dead-turbo, personal-bankrupcy threads on RL dating back about 5 years, i'm in the LESS-THAN-50,000-milebeliever club; not the MORE THAN club. can the 968 Turbo be driven daily ? sure.... in much the same fashion that you can dedicate yourself to dating strippers and **** stars. you can do it, but you better be prepared to pay. driving a Turbo S replica in no way/shape/or form resembles the driving experience associated with a muscle-car engine. the 968 Turbo engine is a life-on-the-edge, low-level exotic, requiring the scale of care and expectation of consequences that you would normally associate with other exotics.... replacing timing belts and associated parts, H20 pumps, turbing related items, rod-bearings, head gaskets, seals, oil cooler lines etc (to keep a semi-exotic engine out of trouble), and tuning are just part of what goes along with a 100,000 mile 968 Turbo driving program. you can do it, but if you're not doing it yourself, you'll be paying someone else a significant quantity of cash to get to 100,000 miles and beyond with a proper running car.
.
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My $.02 worth..
07-06-2012, 04:17 PM
#21
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deep pockets Raj, 2.5, 2.7, 3.0, 3.2.... the dna is about the same.
never said you can't do it. but people tend to tune-em like they stole-em.
if they do, they better bring a suitcase full of money.
never said you can't do it. but people tend to tune-em like they stole-em.
if they do, they better bring a suitcase full of money.
07-06-2012, 04:30 PM
#22
Rennlist Member
BTW, I am not on any payroll
07-06-2012, 08:12 PM
#26
Burning Brakes
This all seems fairly straightforward to me. There is a certain limit to how much power/torque this car can reliably handle - probably somewhere in the 350-375 hp range. If you go above that, either via a high-boost turbo, or by dropping in a small block, reliability and longevity will be compromised.
And I completely agree with Raj that the complexity of swapping in a Chevy V8, when you take into account all the issues associated with the compatibility of the electricals, dealing with the harmonics, making the necessary chassis modifications to handle the vastly different torque characteristics, modifying the gearing for the same reason, and on and on and on, you've got yourself a project every bit as complex and expensive as any turbo mod.
And I completely agree with Raj that the complexity of swapping in a Chevy V8, when you take into account all the issues associated with the compatibility of the electricals, dealing with the harmonics, making the necessary chassis modifications to handle the vastly different torque characteristics, modifying the gearing for the same reason, and on and on and on, you've got yourself a project every bit as complex and expensive as any turbo mod.
07-06-2012, 09:25 PM
#27
Re: V8 swap. I understand that there are a few competent, honest shops who are able to successfully pull this off, so no disrespect toward them. But here's the problem I have with this approach: After going through considerable effort and expense (especially if you pay one of said qualified shops to do the job), what do you have? A car with a V8 up front, a transaxle in the back, that's slightly over 170 enches long, and weighs in the low 3000 pound range. In other words, you basically have a Corvette. While a Corvette is a pefrectly fine car, this leaves me scratching me head over why you wouldn't save yourself all the headaches, and just buy a used Corvette, other than the "uniqueness factor," of course. Also, while I'm the farthest thing from a purist, imho, a V8 burble emanating from the tailpipe of a Porshce is just.... wrong.
07-07-2012, 12:05 AM
#28
Burning Brakes
OK, you've got me there - that does sound pretty nice 
. Have you ever listened to yours next to a Chevy V8? To me, yours somehow sounds more "European", but I could be imagining that. Very nice car, at any rate.
But you also make my point - if you want a nice car with a V8 up front putting the power through a torque tube to a rear transaxle, why not buy a Corvette or a 928? Seems like putting one in a 968, while certainly possible, would be a nightmare that would take years to get sorted.
. Have you ever listened to yours next to a Chevy V8? To me, yours somehow sounds more "European", but I could be imagining that. Very nice car, at any rate.But you also make my point - if you want a nice car with a V8 up front putting the power through a torque tube to a rear transaxle, why not buy a Corvette or a 928? Seems like putting one in a 968, while certainly possible, would be a nightmare that would take years to get sorted.
07-07-2012, 12:18 AM
#29
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one of the biggest problems turbo guys face now, is that good engine builders are few and far between—even to the point of disappearing altogether... the machine work and parts alone, are a small fortune. but, i will concede that success is fully attainable. but you're getting into a lot of $$$ with a turbo project ($25~30 k), and semi-exotic engine program (and tuning) thereafter...
by contrast, the V8 swaps are cake.... first, because there are plenty of decent and inexpensive gen III engines, costs can be controlled... but as you mention, the swap itself requires a fairly long list of parts—and the $$$$ does add up fast... but virtually all the parts are straight bolt-ins—with only moderate amounts of fabbing—like Mustang hydroboost brakes, nascar oil cooler... (i'm running my Porsche ps pump/hoses with the help of a custom serpentine bracket)... heat, AC and intake plumbing are just a matter of matching up fittings and cutting the right lenghth of hose.... before getting to these, you begin with a modified cross member, bumpsteer kit, motor mounts, bellhousing adaptor (the crucial part w/ very close tolerances), oil pan, transmission brace and modified headers.... and a few other minor installations, but overall, very little fabbing to do... and, as far as spending endless time getting things sorted - that was five~ten years ago.... all will be well-within spec for proper driveline geometry/long-term functionality.
parts kit; https://rennlist.com/forums/for-sale...-swap-kit.html
this is absolutely not true... it has been demonstrated over and over that the 968 driveline can handle upwards of 500~550 hp without failures..... in the transaxle Porsche era, there have been some problems with some of the early 944 transmissions when taking on full power.... also, the 928-25mm and 28mm driveshafts both have a common problem with shearing (under extreme torque) at the necked down areas where the shaft contains less mass.... but in the case of the 968... we're in the clear. the driveshafts and input shafts can take a lot of power... the stock cv joints are an issue, but not so much if you're running a transmission brace and distributing power via LSD, ... but if you're running 500 hp++ on the track, or you plan on doing burnouts all over creation, XSChop has these rather bulletproof chrome moly units available.
https://rennlist.com/forums/for-sale...944-951-a.html
with the swap fully, completed, you've now added about 20 pounds to the front wheels... but this weight can be eliminated later with the help of a couple of mods... the Porsche 3.0 is the engine that has the most issues with vibrations of nearly any engine ever produced for a production car... after you've run through a set of motor mounts, you run the risk of cracking your oil pick up tube... then, other engine accessories can experience excessive wear or premature failure, including water pumps, ac pumps and timing belts - all being shaken abnormaly. by contrast, when was the last time you had to change the motor mounts on your 1973 Chevelle SS ? by comparison, (short of a V12), V8s are very smooth running engines.
http://www.thetruthaboutcars.com/2006/07/v8s-rule/
what you need are big brakes (something most of the Rennlisters have completed long before they get involved with engine swaps), and simply keep either your regular suspension (or M030) bushings, strut mounts, caster blocks (etc), fresh and then, run a strut brace, and you're home... at this point, your suspension and brakes are fully ready for V8 power.
new 5th and 6th gears installed into the transmission ($2,500).
optional; new 3rd, 4th, 5th, and 6th gears + LSD ($5,000 or more).
if you run a Turbo, you'd do well run a taller R&P and .729 6th gear. (about $6,000).
finally there's the wiring....
the 968 is an engine with very straightforward electrical components, and the Chevrolet harness and engine management system is, itself, a good deal more complex than your standard variocam wires... but, the CAR's overall electrical system will bear no prejudice to any other engine being in there, and connecting to it's associated wiring harness... the only issue here is the matter of sorting the Chevy's wires, and packaging it all into a neat workable space, before connecting it to the 968. but, you just let these guys do that for you and then simply connect everything (labeled) to the injectors, coil harness, sensors, and 968.
http://psiconversion.com/
finally, you've got your oil pressure sender, H20 temperature sender, and tach. connecting requires 2 $30 parts from Autozone.... the Chevy engine already sends a 4 cylinder signal to the tach, so nothing to do there.
.
by contrast, the V8 swaps are cake.... first, because there are plenty of decent and inexpensive gen III engines, costs can be controlled... but as you mention, the swap itself requires a fairly long list of parts—and the $$$$ does add up fast... but virtually all the parts are straight bolt-ins—with only moderate amounts of fabbing—like Mustang hydroboost brakes, nascar oil cooler... (i'm running my Porsche ps pump/hoses with the help of a custom serpentine bracket)... heat, AC and intake plumbing are just a matter of matching up fittings and cutting the right lenghth of hose.... before getting to these, you begin with a modified cross member, bumpsteer kit, motor mounts, bellhousing adaptor (the crucial part w/ very close tolerances), oil pan, transmission brace and modified headers.... and a few other minor installations, but overall, very little fabbing to do... and, as far as spending endless time getting things sorted - that was five~ten years ago.... all will be well-within spec for proper driveline geometry/long-term functionality.
parts kit; https://rennlist.com/forums/for-sale...-swap-kit.html
this is absolutely not true... it has been demonstrated over and over that the 968 driveline can handle upwards of 500~550 hp without failures..... in the transaxle Porsche era, there have been some problems with some of the early 944 transmissions when taking on full power.... also, the 928-25mm and 28mm driveshafts both have a common problem with shearing (under extreme torque) at the necked down areas where the shaft contains less mass.... but in the case of the 968... we're in the clear. the driveshafts and input shafts can take a lot of power... the stock cv joints are an issue, but not so much if you're running a transmission brace and distributing power via LSD, ... but if you're running 500 hp++ on the track, or you plan on doing burnouts all over creation, XSChop has these rather bulletproof chrome moly units available.
https://rennlist.com/forums/for-sale...944-951-a.html
with the swap fully, completed, you've now added about 20 pounds to the front wheels... but this weight can be eliminated later with the help of a couple of mods... the Porsche 3.0 is the engine that has the most issues with vibrations of nearly any engine ever produced for a production car... after you've run through a set of motor mounts, you run the risk of cracking your oil pick up tube... then, other engine accessories can experience excessive wear or premature failure, including water pumps, ac pumps and timing belts - all being shaken abnormaly. by contrast, when was the last time you had to change the motor mounts on your 1973 Chevelle SS ? by comparison, (short of a V12), V8s are very smooth running engines.
http://www.thetruthaboutcars.com/2006/07/v8s-rule/
what you need are big brakes (something most of the Rennlisters have completed long before they get involved with engine swaps), and simply keep either your regular suspension (or M030) bushings, strut mounts, caster blocks (etc), fresh and then, run a strut brace, and you're home... at this point, your suspension and brakes are fully ready for V8 power.
new 5th and 6th gears installed into the transmission ($2,500).
optional; new 3rd, 4th, 5th, and 6th gears + LSD ($5,000 or more).
if you run a Turbo, you'd do well run a taller R&P and .729 6th gear. (about $6,000).
finally there's the wiring....
the 968 is an engine with very straightforward electrical components, and the Chevrolet harness and engine management system is, itself, a good deal more complex than your standard variocam wires... but, the CAR's overall electrical system will bear no prejudice to any other engine being in there, and connecting to it's associated wiring harness... the only issue here is the matter of sorting the Chevy's wires, and packaging it all into a neat workable space, before connecting it to the 968. but, you just let these guys do that for you and then simply connect everything (labeled) to the injectors, coil harness, sensors, and 968.
http://psiconversion.com/
finally, you've got your oil pressure sender, H20 temperature sender, and tach. connecting requires 2 $30 parts from Autozone.... the Chevy engine already sends a 4 cylinder signal to the tach, so nothing to do there.
.
Last edited by odurandina; 07-07-2012 at 09:15 PM.
07-07-2012, 11:44 AM
#30
OK, you've got me there - that does sound pretty nice . Have you ever listened to yours next to a Chevy V8? To me, yours somehow sounds more "European", but I could be imagining that. Very nice car, at any rate.
But you also make my point - if you want a nice car with a V8 up front putting the power through a torque tube to a rear transaxle, why not buy a Corvette or a 928? Seems like putting one in a 968, while certainly possible, would be a nightmare that would take years to get sorted.
. Have you ever listened to yours next to a Chevy V8? To me, yours somehow sounds more "European", but I could be imagining that. Very nice car, at any rate.But you also make my point - if you want a nice car with a V8 up front putting the power through a torque tube to a rear transaxle, why not buy a Corvette or a 928? Seems like putting one in a 968, while certainly possible, would be a nightmare that would take years to get sorted.