Lets build a mid-engine Trans Am - need advice
Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
Well, I thought GM made the later 4L80E's with a removable bellhousing, but it turns out they don't. The units being put in C5/C6 vettes are custom built and very expensive. So I'm not going to be able to use torque tube parts for the housing. That's ok though, I have some ideas to make it work.
I'm pretty sure the torque converter needs at least one support bearing to keep it spinning true. It's postioning is crucial. From that bearing to the engine ISN'T crucial which means the trans and engine don't have to be perfectly lined up. Just as long as it's close. That's a big help since I'm going to fab up a "bellhousing extension" from steel tubing and cover it with sheetmetal. Strong and light is what I hope to make with just enough room to fit the differential in there as far as I can.
I'm pretty sure the torque converter needs at least one support bearing to keep it spinning true. It's postioning is crucial. From that bearing to the engine ISN'T crucial which means the trans and engine don't have to be perfectly lined up. Just as long as it's close. That's a big help since I'm going to fab up a "bellhousing extension" from steel tubing and cover it with sheetmetal. Strong and light is what I hope to make with just enough room to fit the differential in there as far as I can.
Last edited by JasonWW; Feb 7, 2009 at 12:34 AM.
Thread Starter
Joined: Sep 2004
Posts: 6,814
Likes: 3
From: Hou. TX.
Here is a very rough picture of my drivetrain idea with the suspension. There are a few bugs with the lower control arm mounting points near the engine, but they can be worked out. The real issue seems to be halfshaft length. When you move the diff from the center your going to get one really short shaft. The other side has to mimic it.
Keep in mind the engine and trans are probably not to correct scale.
One solution would be to offset the drivetrain. If I move it to the left 5", then it will add 5" to each halfshaft. See where I'm going? I'll need to do some more measuring to get actual dimensions.
I could also widen the back of the car.
Keep in mind the engine and trans are probably not to correct scale.
One solution would be to offset the drivetrain. If I move it to the left 5", then it will add 5" to each halfshaft. See where I'm going? I'll need to do some more measuring to get actual dimensions.
I could also widen the back of the car.
Last edited by JasonWW; Feb 9, 2009 at 09:33 PM.
Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
Swapping in an IRS is also an option on the 99. I'll have to figure out where I want the tank after the hard part is over.
If I get the white 98 going with a mid-engine setup, then everything gets turned around. The tank and sub box will be up front.
Last edited by JasonWW; Feb 9, 2009 at 11:04 PM.
Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
I've been racking my brain on this longitudinal setup and I'm going a bit crazy. So I'm going to switch gears and take a close look at a transverse setup again.
Mainly GM's heavy duty first gen transverse, the 4T80-E. This is the trans that's used in most of he big front wheel drive Caddys. They are rated at 300hp, but can be used in vehicles up to 8000lbs. I'll have more power, but will be lighter than the big Caddys so maybe it will hold up. I need to find out if it will physically fit and if our PCM can control it. They are going for around $400 used. Not bad. I'm starting to not care about the final drive ratio or if it has a LSD. I just want it to work.
Mainly GM's heavy duty first gen transverse, the 4T80-E. This is the trans that's used in most of he big front wheel drive Caddys. They are rated at 300hp, but can be used in vehicles up to 8000lbs. I'll have more power, but will be lighter than the big Caddys so maybe it will hold up. I need to find out if it will physically fit and if our PCM can control it. They are going for around $400 used. Not bad. I'm starting to not care about the final drive ratio or if it has a LSD. I just want it to work.
Last edited by JasonWW; Feb 10, 2009 at 01:56 AM.
TECH Apprentice
Joined: Jul 2007
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Does it matter?
I guess no, it doesn't matter, but what's the point of your thread?
To be an *** whenever someone asks you a question about your build?
To tell you the truth, I was interested, so I asked. Still trying to learn and all that.
Do yourself a favor and lose the attitude.
Last edited by 92builtbird; Feb 11, 2009 at 11:12 PM.
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TECH Enthusiast
Joined: Oct 2007
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From: NC
Uhhh, it was a question *****, no need to be a dick about it
I guess no, it doesn't matter, but whats the point of you're thread?
To be an *** whenever someone asks you a question about your build?
To tell you the truth, I was interested, so I asked. Still trying to learn and all that.
Do yourself a favor and lose the attitude
I guess no, it doesn't matter, but whats the point of you're thread?
To be an *** whenever someone asks you a question about your build?
To tell you the truth, I was interested, so I asked. Still trying to learn and all that.
Do yourself a favor and lose the attitude
Thread Starter
Joined: Sep 2004
Posts: 6,814
Likes: 3
From: Hou. TX.
Oh, NOW I'm pissed.
That was a simple rhetorical question. No, it does not matter to me because there is no better solution. If you know how to do this with less drivetrain loss, please speak up.
You two are the one showing your true colors. Maybe mommy beat you with a wire hanger so now your angry and you hear attitude everywhere. I don't know.
That was a simple rhetorical question. No, it does not matter to me because there is no better solution. If you know how to do this with less drivetrain loss, please speak up.
You two are the one showing your true colors. Maybe mommy beat you with a wire hanger so now your angry and you hear attitude everywhere. I don't know.
Last edited by JasonWW; Feb 12, 2009 at 05:47 AM.
TECH Apprentice
Joined: Jul 2007
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Oh, NOW I'm pissed.
That was a simple rhetorical question. No, it does not matter to me because there is no better solution. If you know how to do this with less drivetrain loss, please speak up.
You two are the one showing your true colors. Maybe mommy beat you with a wire hanger so now your angry and you hear attitude everywhere. I don't know.
That was a simple rhetorical question. No, it does not matter to me because there is no better solution. If you know how to do this with less drivetrain loss, please speak up.
You two are the one showing your true colors. Maybe mommy beat you with a wire hanger so now your angry and you hear attitude everywhere. I don't know.
No, I don't know how to do it with less drive train loss, hense the question.
And to make a remark about my mom, on an internet forum is pretty childish.
I know nothing about you, and you know nothing about me, so keep sounding like a hardass.
TECH Enthusiast
Joined: Oct 2007
Posts: 605
Likes: 0
From: NC
Oh, NOW I'm pissed.
That was a simple rhetorical question. No, it does not matter to me because there is no better solution. If you know how to do this with less drivetrain loss, please speak up.
You two are the one showing your true colors. Maybe mommy beat you with a wire hanger so now your angry and you hear attitude everywhere. I don't know.
That was a simple rhetorical question. No, it does not matter to me because there is no better solution. If you know how to do this with less drivetrain loss, please speak up.
You two are the one showing your true colors. Maybe mommy beat you with a wire hanger so now your angry and you hear attitude everywhere. I don't know.
Teching In
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They are rated at 300hp, but can be used in vehicles up to 8000lbs. I'll have more power, but will be lighter than the big Caddys so maybe it will hold up.
Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
The newest (2nd gen) transverse from GM and Ford (they teamed up to build it) is a 6sp unit and is considered medium duty. The 6T70/6T75. It's still rated at about the same 300hp. I doubt they will build a heavy duty version.
The problem is GM and Ford are not building any heavy front wheel drive vehicles like the Toronados. It's not economical. Instead they limit the transverse transmissions to light and medium duty and then focus the heavy duty trans for longitudinal mounting which is what almost all trucks are. Even the few big FWD cars we have are only going to get lighter due to government regulations.
The reason I'm looking at Ford and GM is because of the higher number of transmissions they produce. This keeps the price low. The fewer made the more they cost. Small production mid-engine manual transmissions from Mendoela and Hewland, for example, cost in the $10k-$15k range. In the middle are Audi (up to 300hp and $2k-$3k) and Porsche (500hp+ $6k+). The older ZF boxes are still in the $10k+ range.
Last edited by JasonWW; Feb 12, 2009 at 10:54 PM.
TECH Apprentice
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Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
That IS my answer. What, you don't believe me?
First, there's no rule that I have to answer any of your questions.
Second, it's already been asked and answered. See post 81.
Third, you obvioulsy haven't read this thread or else you wouldn't have asked it. As far as I'm concerned, people who haven't read the thread shouldn't be allowed to ask any questions. (Unless it's a good one)
I'm taking a break from this thread to work on the front suspension redesign. Later.
First, there's no rule that I have to answer any of your questions.
Second, it's already been asked and answered. See post 81.
Third, you obvioulsy haven't read this thread or else you wouldn't have asked it. As far as I'm concerned, people who haven't read the thread shouldn't be allowed to ask any questions. (Unless it's a good one)
I'm taking a break from this thread to work on the front suspension redesign. Later.
Last edited by JasonWW; Feb 13, 2009 at 02:03 AM.
I remember in an episode of monster garage they used a v-drive on a boat project? cant remember for sure since it was so long ago but if I remember correctly they had some power behind it, have you thought about, or would it even be possible to use a marine v-drive? they might be cheaper than those units you were talking about, but really I have no idea. im just throwing ideas out
Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
That episode of MG has been talked about. It was a wheel standing van. The units run about $2,000 new, but are really strong since they are built for top fuel type speed boats. The transfer case is a cheaper solution since it can be had for under $300.
The main difference in the 2 is that Vee drives use 2 gears which means the input and output spin opposite directions. Transfer cases use 3 gears or a chain so that the input and output turn the same direction.
What I need is a gear drive setup that would let me build a modern version of the old Turbo 325/425 transmissions except - the input and output need to turn opposite directions. The 325 and 425 used a chain which spun the transmissions backwards. So they had to have special pumps and other unique parts. If I could run 2 big gears, I could mate an LS1 to a T56 or 4L80E and have a strong, cheap and reliable setup. I wouldn't mount the diff next to the block and run the axle through the oilpan, though. I would mount the diff in front of the harmonic balancer. That way you can mount the engine nice and low.
If I could built it and patent such a gearbox, I would be rich. Seriously, demand is high for such a unit.
The main difference in the 2 is that Vee drives use 2 gears which means the input and output spin opposite directions. Transfer cases use 3 gears or a chain so that the input and output turn the same direction.
What I need is a gear drive setup that would let me build a modern version of the old Turbo 325/425 transmissions except - the input and output need to turn opposite directions. The 325 and 425 used a chain which spun the transmissions backwards. So they had to have special pumps and other unique parts. If I could run 2 big gears, I could mate an LS1 to a T56 or 4L80E and have a strong, cheap and reliable setup. I wouldn't mount the diff next to the block and run the axle through the oilpan, though. I would mount the diff in front of the harmonic balancer. That way you can mount the engine nice and low.
If I could built it and patent such a gearbox, I would be rich. Seriously, demand is high for such a unit.
Last edited by JasonWW; Feb 13, 2009 at 08:31 AM.
Thread Starter
Joined: Sep 2004
Posts: 6,814
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From: Hou. TX.
If you look on YouTube for "big block fiero" you'll see a crazy one with a huge blower on it running a Turbo 425 trans.
The struts seem to be missing. My guess is that the rear suspension is fixed into place to make wheelstands easier.
The struts seem to be missing. My guess is that the rear suspension is fixed into place to make wheelstands easier.
Last edited by JasonWW; Feb 13, 2009 at 08:48 AM.