To much torque
06-12-2012, 11:46 AM
#1
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To much torque I am building (rebuilding) a Fiberfab Valkyrie kit car. Car was originally assembled in 1971, driven for 7k miles before they ditched it, breaking the passenger side fiberglass under and around the seat, and breaking a bolt hole where the rear trailing arm attaches to the differential, they took it apart to fix it, and there it sat for 30 years until l I picked it up for a grand.
I've replaced the dif housing and picked up a 120k mile l33 for $975
Of course I've started looking and I am finding that the l33 probably has 330 torque stock. and the Corvair transaxle/diff combo is only good to 300
My first and most pressing question is, without spending a ton of money is their any way to lower the torque?
Not a common problem I realize, I know its pretty easy to move the torque up the power band, and reduce low end torque, witch may suffice, as then it wouldn't be hitting it all at once from a stop.
I am looking into upgrading the diff, but there don't seem to be many options.
Car only weighs about 1800. maybe a bit less with the aluminum block and some other upgrades I plan, so it should be one wild ride, I wanted to throw a turbo on it, and hoped to get 550 hp but I don't think i can do that without over torquing the trans/diff and blowing pieces of it all over the drag strip.
Any help is appreciated, also will be looking for ideas on connecting the trans to the crank and motor mounting ideas.
Also I was wondering, on a trans it seems like the shock would be the killer of parts, so wouldn't a given transmision in a much lower weight car be able to handle a bit more torque?
I've replaced the dif housing and picked up a 120k mile l33 for $975
Of course I've started looking and I am finding that the l33 probably has 330 torque stock. and the Corvair transaxle/diff combo is only good to 300
My first and most pressing question is, without spending a ton of money is their any way to lower the torque?
Not a common problem I realize, I know its pretty easy to move the torque up the power band, and reduce low end torque, witch may suffice, as then it wouldn't be hitting it all at once from a stop.
I am looking into upgrading the diff, but there don't seem to be many options.
Car only weighs about 1800. maybe a bit less with the aluminum block and some other upgrades I plan, so it should be one wild ride, I wanted to throw a turbo on it, and hoped to get 550 hp but I don't think i can do that without over torquing the trans/diff and blowing pieces of it all over the drag strip.
Any help is appreciated, also will be looking for ideas on connecting the trans to the crank and motor mounting ideas.
Also I was wondering, on a trans it seems like the shock would be the killer of parts, so wouldn't a given transmision in a much lower weight car be able to handle a bit more torque?
06-12-2012, 12:29 PM
#3
There is at least one post on here from a guy in I think Australia that had to limit the power to make his engine swap legal. It does happen.
All sorts of ways to lower torque output. Just read through old posts of guys who fixed a problem to go faster then do the opposite of what they did.
The quickest and cheapest way I can think of is to just remove a couple of plug wires. Detuning the motor by retarding the timing will work also. Might eat some gas that way.
Another option would be to put some type restriction in the intake plumbing. Just like NASCAR has done at times.
If you really want to get fancy you could get an ECU with traction control and reprogram that.
Of course you could also just modulate the throttle. That way you still have full power when you can use it. Or skinny tires. Not being able to hook has saved many a drivetrain.
All sorts of ways to lower torque output. Just read through old posts of guys who fixed a problem to go faster then do the opposite of what they did.
The quickest and cheapest way I can think of is to just remove a couple of plug wires. Detuning the motor by retarding the timing will work also. Might eat some gas that way.
Another option would be to put some type restriction in the intake plumbing. Just like NASCAR has done at times.
If you really want to get fancy you could get an ECU with traction control and reprogram that.
Of course you could also just modulate the throttle. That way you still have full power when you can use it. Or skinny tires. Not being able to hook has saved many a drivetrain.
06-12-2012, 12:57 PM
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When it comes time to rebuild I will be destroking it for sure, but I don't want to do that for a long time.
I am pretty sure switching to a LS1 intake will add a couple RPMs and move the torque up in the power-band, but in my opinion they want stupid amounts of cash for the intakes considering the cost of brand new aftermarket intakes, plus then id have to get new injectors and a car harness, though i am considering it.
I am only into this for $2200 so far (plus 700+ in shipping) and I was hopeing to get it all done for 4-5k without paint, only leaves me 1300-2300 and there are a lot of little parts and pieces I need.
I had the motor in my 90 vette rebuilt, and beefed up, cost me 5 grand, might be jsut over 350 hp, so I guess what I am saying is, LS motors are MONSTERS!
I am pretty sure switching to a LS1 intake will add a couple RPMs and move the torque up in the power-band, but in my opinion they want stupid amounts of cash for the intakes considering the cost of brand new aftermarket intakes, plus then id have to get new injectors and a car harness, though i am considering it.
I am only into this for $2200 so far (plus 700+ in shipping) and I was hopeing to get it all done for 4-5k without paint, only leaves me 1300-2300 and there are a lot of little parts and pieces I need.
I had the motor in my 90 vette rebuilt, and beefed up, cost me 5 grand, might be jsut over 350 hp, so I guess what I am saying is, LS motors are MONSTERS!
06-12-2012, 01:02 PM
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depending on what you do with intake and exhaust, it could be a non-issue If you go with a LS1 intake off of a Camaro/Firebird that will reduce torque some.
2nd - if you put exhaust that is restrictive on it (which seems likely based on the amount of room you have to mount everything) that would restrict it as well.
3rd - get it tuned once it is in, and tell the tuner what you want. They can tune torque out if needed (not optimal, and you may have to look around to find a tuner to do this).
Last - if you can sell the LM33 and buy a 4.8l LR4 instead - problem is automatically solved.
Good luck!
2nd - if you put exhaust that is restrictive on it (which seems likely based on the amount of room you have to mount everything) that would restrict it as well.
3rd - get it tuned once it is in, and tell the tuner what you want. They can tune torque out if needed (not optimal, and you may have to look around to find a tuner to do this).
Last - if you can sell the LM33 and buy a 4.8l LR4 instead - problem is automatically solved.
Good luck!
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06-12-2012, 01:32 PM
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My target weight is 1500 pounds, stated at just under 1800, switching to an l33 from a SBC drops me about 141 pounds to roughly 1650,
Plans include aluminum radiator, plastic gas tank, newer style and lighter brake and clutch components lexan for the huge back glass window, removing the carpet and painting the interior (will use mats for daily driving and remove them at the track)
I am hoping that will get me down to the 1500, but then later I want to add a cage and cut out the existing cast into the fiberglass seats and droping the floor pan, so that I can put Vette seats in so that it isnt quite so uncomfortable.
so switching to the iron 4.8 really isnt an option at this point, though id consider a crank swap if I didnt figure it was going to cost me an arm and a leg. But I guess i should look into it further
Plans include aluminum radiator, plastic gas tank, newer style and lighter brake and clutch components lexan for the huge back glass window, removing the carpet and painting the interior (will use mats for daily driving and remove them at the track)
I am hoping that will get me down to the 1500, but then later I want to add a cage and cut out the existing cast into the fiberglass seats and droping the floor pan, so that I can put Vette seats in so that it isnt quite so uncomfortable.
so switching to the iron 4.8 really isnt an option at this point, though id consider a crank swap if I didnt figure it was going to cost me an arm and a leg. But I guess i should look into it further
06-12-2012, 01:54 PM
#9
Detuning the engine isn't really a problem honestly. Also if that transaxle is good to 300ftlbs then what is the weight of the original vehicle it came in. From what I've seen the lighter the vehicle the more power a transmission can take even dead hooking.
06-12-2012, 02:33 PM
#11
I think you will be fine at least for a while. The car will be very light and as long as you drive reasonably I think the weak link will be traction. If the car doesnt hook up it is less likely to break the trans. Put it together drive it for a while and save your money for a stronger transmission. I have an old VW GT40 kit car i want to do the same thing with but mine was not as near complete as yours is.
06-12-2012, 03:44 PM
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Didn't Corvair motors spin the wrong way? I'm guessing that this trans is turned around to make it mid engine... if this is the case the trans will be even weaker as you are running on the back side of the ring gear teeth. might be better off finding a different trans to use maybe Porsche Boxster or Audi a4 fwd trans just an idea... good luck on your project
06-12-2012, 04:34 PM
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They are flipped, but the kit came with its own input shaft to alleviate the rotational problem, and was recommended for a 327 SBC of up to 350 HP, the 450+ hp model required the pantera transaxle.
the trans itself is the same saginaw 4 speed they put in the vette (on 66 and later corvairs) Its the differential that's the problem.
Getting part of your top end power from a turbo pushes the limits a little higher cus the power comes on late after the launch (unless your dumping the clutch at 4k RPMS)
Upgrading the differential to a 4 spider gear posi unit gets you into a 400 hp rating for about 6-$800, that is somethign I plan to do, but not till next year or later.
the trans itself is the same saginaw 4 speed they put in the vette (on 66 and later corvairs) Its the differential that's the problem.
Getting part of your top end power from a turbo pushes the limits a little higher cus the power comes on late after the launch (unless your dumping the clutch at 4k RPMS)
Upgrading the differential to a 4 spider gear posi unit gets you into a 400 hp rating for about 6-$800, that is somethign I plan to do, but not till next year or later.
06-12-2012, 08:36 PM
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UHG, been looking al lday for how to get the 4 spyder geared Diff kit and cant find it. spyder gear is suposed to be the weakest link and significantly increase handeling up to as much as 580 hp.
if i HAVE to spend money to reolve the problem, it will be to upgrade the Dif, not downgrade the intake, though a less efficient tune may be the way to go for basivcally free becouse I need to get it retuned to stand alone anyhow
if i HAVE to spend money to reolve the problem, it will be to upgrade the Dif, not downgrade the intake, though a less efficient tune may be the way to go for basivcally free becouse I need to get it retuned to stand alone anyhow
06-14-2012, 11:01 AM
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When in doubt, go to the source. With a little more searching i found the original manual from the manufacturer.
http://www.fiberfab.us/manuals/earlyvalkyrie.pdf
Says the special shaft ups the rating to 375 torque and 375 HP, after that it has to be upgraded to the four spider gear differential... or if you are anticipating hard starts such as drag racing....
I also found out that they made a production model of this car, with the 450 hp big block and the Pantera transaxle they claimed a top speed of 180 MPH, and that it was the fastest production car in the world, even came with a parachute.
I am still looking to the 4 spider gear upgrade, as id still like to throw a turbo on here and pass the 500 hp mark. For the moment, I am jsut going to build it as is though,
Took the body off last night, wire brushing all the rust off, and repainting the frame, repainted the trans asembly as well, I supose I should start a build thread and post pictures.
http://www.fiberfab.us/manuals/earlyvalkyrie.pdf
Says the special shaft ups the rating to 375 torque and 375 HP, after that it has to be upgraded to the four spider gear differential... or if you are anticipating hard starts such as drag racing....
I also found out that they made a production model of this car, with the 450 hp big block and the Pantera transaxle they claimed a top speed of 180 MPH, and that it was the fastest production car in the world, even came with a parachute.
I am still looking to the 4 spider gear upgrade, as id still like to throw a turbo on here and pass the 500 hp mark. For the moment, I am jsut going to build it as is though,
Took the body off last night, wire brushing all the rust off, and repainting the frame, repainted the trans asembly as well, I supose I should start a build thread and post pictures.
Last edited by Crazier; 06-14-2012 at 11:06 AM.
06-14-2012, 05:48 PM
#17
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When in doubt, go to the source. With a little more searching i found the original manual from the manufacturer.
http://www.fiberfab.us/manuals/earlyvalkyrie.pdf
Says the special shaft ups the rating to 375 torque and 375 HP, after that it has to be upgraded to the four spider gear differential... or if you are anticipating hard starts such as drag racing....
I also found out that they made a production model of this car, with the 450 hp big block and the Pantera transaxle they claimed a top speed of 180 MPH, and that it was the fastest production car in the world, even came with a parachute.
I am still looking to the 4 spider gear upgrade, as id still like to throw a turbo on here and pass the 500 hp mark. For the moment, I am jsut going to build it as is though,
Took the body off last night, wire brushing all the rust off, and repainting the frame, repainted the trans asembly as well, I supose I should start a build thread and post pictures.
http://www.fiberfab.us/manuals/earlyvalkyrie.pdf
Says the special shaft ups the rating to 375 torque and 375 HP, after that it has to be upgraded to the four spider gear differential... or if you are anticipating hard starts such as drag racing....
I also found out that they made a production model of this car, with the 450 hp big block and the Pantera transaxle they claimed a top speed of 180 MPH, and that it was the fastest production car in the world, even came with a parachute.
I am still looking to the 4 spider gear upgrade, as id still like to throw a turbo on here and pass the 500 hp mark. For the moment, I am jsut going to build it as is though,
Took the body off last night, wire brushing all the rust off, and repainting the frame, repainted the trans asembly as well, I supose I should start a build thread and post pictures.
06-14-2012, 07:22 PM
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I didn't read all the posts. This may have been said already. Your car being lighter will help the diff and drive line live longer. Also you have to get the torque to stick to the group.d to hurt it. Look around on some corvair forums. There has to be some aftermarket parts to beef everything up. A friend of mine had a northstar with twin turbos in a GT40 kit car. He mated the engine to a Getrag(sp) 5spd transaxle. Out of a 94 cutlas supreme. The car was crazy fast and would break the clutch or trans all the time. He had to adapt a multi disc clutch and have a bunch of billet parts machined for the transaxle. Another kit that uses ls1 family engines is the Ultima GTR. It uses Porsche driveline. This could be a future upgrade.
06-14-2012, 07:50 PM
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Not sure how strong of a frame you have, if you're shooting for 1500 lb.
My opel was ~1800 lbs stock. The problem is, that there's a reason why it's so light - the frame is light - and light usually = weak. I had to add a 12pt cage and tie it in to the entire body to keep the frame from twisting & breaking/popping windshields with 300+ hp. I'm guessing your car is in the same boat, so to speak.
And, with targets of 550hp and 1500lb, you'll be booted off just about any track after one pass without a full cage. Hell, even with only 300whp, you'll be in the 10's, which requires at least a 6-pt. Plus, you'll need some c-clip eliminators, among lots of other things.
I suggest you read this, if you really plan on racing the car:
http://www.hotrod.com/techarticles/n...time_brackets/
300+ hp in a light (<2000 lb) car is ridiculously overpowered for street use. Assuming you keep the skinny wheels/tires that are on there - which, given your budget, seems to be the only feasible option - you'll can break the rear end loose at just about any speed on a WOT blast. The safety measures are there for if (when) you run into a wall.
I'm not trying to flame, I just wanted to let you know what you're getting yourself into. Especially if the most powerful car you've driven is a 350hp 3000+ lb C4 corvette, which is a slug compared to a 300hp 1800lb car (or a 550hp 1500 lb car, as you intend).
You've got lots of work ahead of you. Most likely, take your budget and triple it if you want something safe, track-legal, and able to utilize the power.
My .02
My opel was ~1800 lbs stock. The problem is, that there's a reason why it's so light - the frame is light - and light usually = weak. I had to add a 12pt cage and tie it in to the entire body to keep the frame from twisting & breaking/popping windshields with 300+ hp. I'm guessing your car is in the same boat, so to speak.
And, with targets of 550hp and 1500lb, you'll be booted off just about any track after one pass without a full cage. Hell, even with only 300whp, you'll be in the 10's, which requires at least a 6-pt. Plus, you'll need some c-clip eliminators, among lots of other things.
I suggest you read this, if you really plan on racing the car:
http://www.hotrod.com/techarticles/n...time_brackets/
300+ hp in a light (<2000 lb) car is ridiculously overpowered for street use. Assuming you keep the skinny wheels/tires that are on there - which, given your budget, seems to be the only feasible option - you'll can break the rear end loose at just about any speed on a WOT blast. The safety measures are there for if (when) you run into a wall.
I'm not trying to flame, I just wanted to let you know what you're getting yourself into. Especially if the most powerful car you've driven is a 350hp 3000+ lb C4 corvette, which is a slug compared to a 300hp 1800lb car (or a 550hp 1500 lb car, as you intend).
You've got lots of work ahead of you. Most likely, take your budget and triple it if you want something safe, track-legal, and able to utilize the power.
My .02
