Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Max HP & TQ in a Cab
#1

Hypothetically speaking, how much power can a stock Cabriolet handle before...? What is a safe amount? Is 400hp + 400tq too much at the wheels?
Partial Post: Please Login or Register to read the full post.

Rustech                       
Reply
#2

i don't think the hp is the problem - that develops at a high point and doesn't subject the chassis to anything unusual, and 400 is probably within reason



torque is another matter - as with any car you put that kind of torque into, the mounts are questionable, as is the first gear shaft and the axle joints - this is why V8 conversions are so hard - the torque comes on so strong and so low that it rips stuff apart - you may need to do some beffing up in those areas



i assume you ask because of the idea of the LS1 going into this car - interesting idea, but here's another thing to think about:



gearing - the V8 is designed to rev a lot lower and develop its power a lot lower than the 968 engine and the gearing that was assigned to it - you may find that the gear spacing and ratios are not compatible for performance driving, and need to be changed
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#3

I'll agree (for once <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> ) with flash on that. Additionally, the style of driving plays an enormous part on equipment longevity. Clutch dump launches are out or you will eventually be picking up drivetrain parts off the ground and stuffing them in the trunk while you wait for a tow truck (been there, done that in my V8 Datsun).



If you can transplant an entire corvette transaxle into the car, that would be the cat's banana. <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.
Reply
#4

Forgive my ignorance, but somwhere some synapsis are firing about something I read in one of the WaterCooled Series books. IIRC, when 968 production went in-house at Porsche from the Audi/VW parts bin sourced 924/944s, the transaxle was sourced from an endurance racer in order to handle the increased torque of the Variocam motor? (I'm thinking 908/910)

Am I High? Then again, that may only be sufficient to cope with ~300# of torque.
Partial Post: Please Login or Register to read the full post.
Reply
#5

probably does - the problem won't likely be the transaxle, but rather the joints and mounts - the torque coming on so low is the problem - it's the change in load ratio that breaks things - 0-250lb/ft at the blip of a throttle is a lot worse than 150-400lb/ft over 1000rpm - V8s generally produce their max torque very low compared to our motors, which means that you will be loading everything at max every time you take off - some real work will have to be done to keep that thing in there - additionally, the gearing will probably have to change to accommodate the different power curve, unless you want to be running the V8 at high revs - this is one of the reasons that dave was talking about transplanting the whole thing - the problem there is the torque tube - that is one of the reasons this car works so well - does the corvette have a torque tube? if not, then that opens up a whole new can of worms



interesting idea, and certainly do-able, but not a simple thing for sure
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#6

[quote name='flash' date='Mar 25 2005, 09:01 AM']... - does the corvette have a torque tube? 

[right][post="2345"]<{POST_SNAPBACK}>[/post][/right][/quote]



Yep.

[Image: 2005%20Chevrolet%20Corvette%20Driveline.jpg]
Partial Post: Please Login or Register to read the full post.
Reply
#7

cool- then it's just the mounts, joints and gearing that are the questionable areas of breakage or complication



still an interesting idea, but i'm getting too old and lazy to do any more V8 conversions



go eric go
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#8

Let's get Rides or one of those shows to pick up this challenge.
Partial Post: Please Login or Register to read the full post.
Reply
#9

I bought a boat in the early winter for this summers vacation trip, and might just sell it after to fund my conversion/hobby. I've been leisurely reading up on the different options of getting more power in this snail of a car (did I just say that) with out interrupting the great balance. My options are a low boost turbocharger (944 heads to lower compression, 951 pipe work..., increases weight biase the most), SFR SC kit (increase weight biase some), or a good old LS1 (can use cams and heads to create a lower torque, higher reving motor without changing the weight biase more than half a percent).



I'm just drooling over the idea of having more power. I could implant a slightly modified LS1 with 400hp 350tq N/A, with a nitrous setup for occasional use. (am I wearing my age on my sleeve)
Partial Post: Please Login or Register to read the full post.

Rustech                       
Reply
#10

Maybe I should just figure out how to put the 968 shell on this:



http://cgi.ebay.com/ebaymotors/ws/eBayISAP...5&category=6783



<img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.

Rustech                       
Reply
#11

The only option in your list that you can currently certify for use in CA is an engine swap. Other devices like super and tubo chargers are not certified, unless a company wants to step up and offer a package with an EO number.
Partial Post: Please Login or Register to read the full post.
Reply
#12

something to think about before considering the V8 - while the motor itself may only be a few pounds heavier, some of the ancillary components won't be - for example, you'll need a bigger radiator for sure - probably bigger oil cooler too



the extra power sounds great - wondering about the driveablity though- running a V8 at 3-4k all the time, doesn't sound like a lot of fun for the motor - i think dave is right about swapping out the whole drivetrain - that seems to be the only way to get the gearing right for the engine, unless somebody has taller gears for our box - i've seen lower ones, but not taller ones - having done this in other cars, this was a constant issue with those too - we had to select diffs and trannies that gave us the gearing so as not ot overrev the V8



good luck - love to see it work out - very interesting project
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#13

Take lots of pictures! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.
Reply
#14

Dave, you'll be able to take the pictures since you'll be helping me. <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />

I know, all the beer in CA wouldn't be enough.



Bob, others have done the conversions with perfect drivability. The TOTAL shift in weight on Renegades conversion was about half a percent. I've done more by removing the ballast weight.



I'm not leaning towards the LS1 anymore than the others really. The idea of being able to hook up the SC in a long weekend is appealing.
Partial Post: Please Login or Register to read the full post.

Rustech                       
Reply
#15

Quote:If you can transplant an entire corvette transaxle into the car, that would be the cat's banana.



Those extra 10 inches of Corvette wheelbase would take some work to deal with! Maybe a custom corvette torque tube would do it. <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />



Eric
Partial Post: Please Login or Register to read the full post.
Reply
#16

eric - i'm not talking abou weight for a change - that one is fairly equal in a normal car - of course, you are light in the rear, which will present additional traction issues with the added torque



as i said, the main thing to wory about is gearing and mounting - the gearing is going to really mess with driveability - running a V8 at 3.5k and up all the time is not my idea of driveable - those engines are designed to lop along on the freeway at 2.5 k or lower - taller final gearing is needed to make it work right in the 968 - not sure where the individual ratios are in the V8 torque curve either - need to look into that too



still, an intersting idea - just a little more research to do to see how it would all come together - it's a lot more than "will it fit?"



i should have some info on the weekend supercharger package in a few more weeks - looks promising so far
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#17

Time = Money. I think you'd be WAAY ahead if you just sold the 968 and bought a 360 Modena

<img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" />

(sorry, I couldn't help it.)
Partial Post: Please Login or Register to read the full post.
Reply
#18

lol - i've had that thought a few times myself on some wild projects - when i was doing the blown 302 944, when i was doing the 289 fiat 124 spyder, when i was doing the 302 mgb, when i was doing the blown 350 vega, when i was doing the twin turbo 240Z, when i was doing the 350 240Z.................



now i'm contemplating somthing nutty for the 968



oh well - ya can't take it with you
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#19

[quote name='flash' date='Mar 25 2005, 07:35 PM']now i'm contemplating somthing nutty for the 968

[right][post="2379"]<{POST_SNAPBACK}>[/post][/right][/quote]

Nutty ........ isn't the word..... <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

[Image: ratfink.jpg]
Partial Post: Please Login or Register to read the full post.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)