Help design LS2 stroker combo!
02-22-2005, 09:59 AM
#21
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Good one guys! No Motec or parts made from unobtainium 
Anyway,
I'm leaning toward the 4.00" x 4.00" 402 LS2 with Callies crank and stock LS2 block, as Mikey suggested and has tested. Stock tuned computer, injection, sump, etc.
Yes, there are several gearsets available for the G50 transaxle (Carquip, Quaife, Powerhaus II, Guard aka GT, etc.), but changing gearsets doesn't address the weakest link....the ring and pinion (It might even be weaker than a Mustang IRS!)
From: http://www.rennsportsystems.com/~porsche/2d.html
Yes, Ultima GTR and Ford GT40 replicas use 'modified' G50's. Attached are pics of spray bar set-ups, billet differential side plates, billet gear forks, etc.
So that's why I was interested in the C5 T56 transaxle. But if it takes significant fabrication, I'll probably skip it. Just wondering if anyone ever inverted one.
E
Anyway,
I'm leaning toward the 4.00" x 4.00" 402 LS2 with Callies crank and stock LS2 block, as Mikey suggested and has tested. Stock tuned computer, injection, sump, etc.
Yes, there are several gearsets available for the G50 transaxle (Carquip, Quaife, Powerhaus II, Guard aka GT, etc.), but changing gearsets doesn't address the weakest link....the ring and pinion (It might even be weaker than a Mustang IRS!)
In order to fit a compact transmission with the requisite features in the 911, Porsche uses very steep hypoid angles on the ring & pinion gears. This make these parts, the most highly stressed part of Porsche transmissions. This requires a GL-5 rated lubricant to protect these components against premature failure. Ring and pinions are problematic areas of these transmissions and require careful setup for any 901, 915, 930, or G50 used for competition or high-horsepower applications.
Yes, Ultima GTR and Ford GT40 replicas use 'modified' G50's. Attached are pics of spray bar set-ups, billet differential side plates, billet gear forks, etc.
So that's why I was interested in the C5 T56 transaxle. But if it takes significant fabrication, I'll probably skip it. Just wondering if anyone ever inverted one.
E
Last edited by kaisenls1; 02-22-2005 at 10:10 AM.
02-22-2005, 10:09 AM
#22
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By the way, good used G50's run about $1500-2000 and the Turbo's G50/50 and G50/02's run about $1000 more. A fully built 'trick' G50/50 with all the mods and spray bars runs about $10000.
That may seem expensive, but how much is a tricked-out T56 and Moser 12 bolt? (Yes, I know some of those hold 1000hp)
E
That may seem expensive, but how much is a tricked-out T56 and Moser 12 bolt? (Yes, I know some of those hold 1000hp)
E
02-22-2005, 11:12 AM
#23
Not a T56 but a 4L60E out of a C5 with trans mated directtly to the motor and the diiff. attached to the trans.
The problem with the C5 T56 vs. G50 is the T56 would push the motor 12" forward. C5s do not have a transaxle but a Trans in the rear mounted directly to the Getrag diff.
The problem with the C5 T56 vs. G50 is the T56 would push the motor 12" forward. C5s do not have a transaxle but a Trans in the rear mounted directly to the Getrag diff.
02-22-2005, 02:43 PM
#25
Originally Posted by kaisenls1
Thanks Polo, you answered my question 
Won't work, gonna stick with G50
E
Won't work, gonna stick with G50
E
I would like to see more cars like the Ultimate or the new Factory Five mid engine car use the T56 as I think it would handle the power and be cheaper to find.http://www.pro-touring.com check out cars then corvairs for pics. A member over there is building a midengine Corvair.
good luck and keep us up to date.
Last edited by 93Polo; 02-22-2005 at 02:48 PM.
02-22-2005, 09:59 PM
#26
So the wb would 12" longer. Might help!
That said, my small displacement idea is, IMHO, the way to deal with a limited torque transaxle. The problem is the electronics. How do you support tuning to 8500 rpm.
The cost? The car is $20k, say $8-10k for a preped transaxle. The motor is over $10k even with stock electronics. And you still need paint, trim, and a donor car. Sounds like over $50k to me.
The extra cost to use a lightweight, short stroke rods and crank is small compared to just the stroker. Maybe $1-1.5k. Using a 4.155 or 4.2 liner adds what? Maybe $1k? Maybe less.
The Jesel is $1500. The Ti valves maybe $1200. Really only need the intake, however I would do the exhaust for reliability.
At 8500rpm, a 3.25" stroke 360 would have the equivalent displacement between a 434 and 441. The intake and heads would probably put the peak closer to 7500rpm.
And 500rwhp at 7500 is only 350lbf-ft of torque. At 6200 it is 425. Coupled with the individual tbs (about $2k more than a FAST/90mm setup) it would have one nice shriek!
Using replacement gears, the higher revs would allow you to have reasonable cruising and performance from the 5 speed.
So mikey, whats the inexpensive way to get 8500 rpm?
That said, my small displacement idea is, IMHO, the way to deal with a limited torque transaxle. The problem is the electronics. How do you support tuning to 8500 rpm.
The cost? The car is $20k, say $8-10k for a preped transaxle. The motor is over $10k even with stock electronics. And you still need paint, trim, and a donor car. Sounds like over $50k to me.
The extra cost to use a lightweight, short stroke rods and crank is small compared to just the stroker. Maybe $1-1.5k. Using a 4.155 or 4.2 liner adds what? Maybe $1k? Maybe less.
The Jesel is $1500. The Ti valves maybe $1200. Really only need the intake, however I would do the exhaust for reliability.
At 8500rpm, a 3.25" stroke 360 would have the equivalent displacement between a 434 and 441. The intake and heads would probably put the peak closer to 7500rpm.
And 500rwhp at 7500 is only 350lbf-ft of torque. At 6200 it is 425. Coupled with the individual tbs (about $2k more than a FAST/90mm setup) it would have one nice shriek!
Using replacement gears, the higher revs would allow you to have reasonable cruising and performance from the 5 speed.
So mikey, whats the inexpensive way to get 8500 rpm?
Last edited by DavidNJ; 02-22-2005 at 10:06 PM.
02-23-2005, 04:14 PM
#27
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David NJ:
The wheelbase wouldn't have to be 12" longer, but:
wheelbase for drag racing = good
wheelbase for road racing = bad
I'm pretty sure the Darton sleeves run closer to $2000 for a LS2...Mikey?
I would think Titanium intakes and sodium filled hollow exhaust (like LS7) would allow the revs.
I wouldn't do Ti exhaust valves; I've heard of heat problems.
I wouldn't need a $8-10K prepped transaxle if I reduced the torque output. Stock gearing will work okay....you only use first gear in the paddock. I'm planning on some ceramic coatings (TB and DFL) and the spray bars.
If I were going short stroke I'd leave it stock bore/stroke LS2 and build for a little more rpm.But I still think the 402 is the way to go.
If class-rules dictated how I build the motor (ala NASCAR, F1, etc.) maybe things would be different, but I'm not a by-the-rules kind of guy
E
The wheelbase wouldn't have to be 12" longer, but:
wheelbase for drag racing = good
wheelbase for road racing = bad
I'm pretty sure the Darton sleeves run closer to $2000 for a LS2...Mikey?
I would think Titanium intakes and sodium filled hollow exhaust (like LS7) would allow the revs.
I wouldn't do Ti exhaust valves; I've heard of heat problems.
I wouldn't need a $8-10K prepped transaxle if I reduced the torque output. Stock gearing will work okay....you only use first gear in the paddock. I'm planning on some ceramic coatings (TB and DFL) and the spray bars.
If I were going short stroke I'd leave it stock bore/stroke LS2 and build for a little more rpm.But I still think the 402 is the way to go.
If class-rules dictated how I build the motor (ala NASCAR, F1, etc.) maybe things would be different, but I'm not a by-the-rules kind of guy
E
02-23-2005, 08:26 PM
#28
You need the big bore for breathing. I believe I've seen the $.155 blocks for $3300. I think from mikey.
You also need to kill that stroke. 3.622 is a big stroke.
Are you going to cryo, REM, nitride and/or induction harden the gears?
David
You also need to kill that stroke. 3.622 is a big stroke.
Are you going to cryo, REM, nitride and/or induction harden the gears?
David
02-23-2005, 08:33 PM
#29
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You need the big bore for breathing. I believe I've seen the $.155 blocks for $3300. I think from mikey.
Gears: Cryo for sure, maybe DFL, that's probably it. Again, the gears themselves are pretty strong, so the SHAFTS are the weaker link (not too bad), but the R&P is the weakest. Cryo would be cost effective, and be for the entire gear/shaft assemblies. Billet shafts are also available, but not very cost effective.
Still thinking 4.00" crank. What do you think Mikey?
E
Last edited by kaisenls1; 02-27-2005 at 10:37 AM.
02-25-2005, 02:08 PM
#31
E,
I noticed you used the words "cost effect." Do you have a planned budget? A G50 is going to cost a few bucks by the time you invert it, add the LSD, change ratio's, and opt for the pump and oiling system. You might want to look at a ZF transaxle (like in the Pantera), and get the best suitable ratio's from the get-go. With that light a weight, the stock G50 ratio's will probably be a bit short, especially 1st. Also, how scarey of a ride are you looking for? At less than 2000lbs, it won't take a whole lot of motor to get your attention! You're likely to get a better balanced package with a lower torque, higher RPM setup, IMHO.
andy1
I noticed you used the words "cost effect." Do you have a planned budget? A G50 is going to cost a few bucks by the time you invert it, add the LSD, change ratio's, and opt for the pump and oiling system. You might want to look at a ZF transaxle (like in the Pantera), and get the best suitable ratio's from the get-go. With that light a weight, the stock G50 ratio's will probably be a bit short, especially 1st. Also, how scarey of a ride are you looking for? At less than 2000lbs, it won't take a whole lot of motor to get your attention! You're likely to get a better balanced package with a lower torque, higher RPM setup, IMHO.
andy1
02-25-2005, 08:11 PM
#33
4" stroke...to do what?
Andy1, I agree, hence my recommendation for a 3-3.335" stroke. However I think you need the big more to unshroud the valves, even with a 350 at those revs.
How do you handle the ECU though?
Also, I think it would end up closer to 2500+# when you add all the little pieces.
Definitely not a race car for beginners. Unless your name is Kimi Raikkonen or Fernando Alonso.
Andy1, I agree, hence my recommendation for a 3-3.335" stroke. However I think you need the big more to unshroud the valves, even with a 350 at those revs.
How do you handle the ECU though?
Also, I think it would end up closer to 2500+# when you add all the little pieces.
Definitely not a race car for beginners. Unless your name is Kimi Raikkonen or Fernando Alonso.
02-26-2005, 06:29 PM
#34
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There will be no problem keeping the weight under 2000 pounds wet without driver.
Lots of carbon fiber, NO frills, street legal (turn signals, lights, safety-glass windshield, horn, DOT tires, etc.)
E
Lots of carbon fiber, NO frills, street legal (turn signals, lights, safety-glass windshield, horn, DOT tires, etc.)
E
