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PostPosted: November 17, 2017, 11:40 pm 
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Not much to report really, but I've started stripping the Impala. Trying to decide just how much of the "goodies" I want to try and keep. Anyone else added a lot of the creature comforts? Regretted it? Regretted NOT adding them?


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PostPosted: November 18, 2017, 2:41 am 
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People see "big giant V8" and get really scared, I think most people don't realize how compact a pushrod V8 is. I modeled up a Midlana frame way back when, here's an LS engine (off of GrabCAD) put in the book engine compartment. It totally fits, better than an overhead cam V6 would for sure, and with less piping, cooling, oil lines, coolant lines, and general ***ery than a turbo setup.

Image

Image

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The only downside to your setup is the automatic transmission. In a car like this, banging through the gears and ripping up tires is most of the fun! I'd be looking long and hard at the G6's F40 6-speed manual, it bolts right up.


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PostPosted: November 21, 2017, 12:48 pm 
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Laminar wrote:
People see "big giant V8" and get really scared, I think most people don't realize how compact a pushrod V8 is. I modeled up a Midlana frame way back when, here's an LS engine (off of GrabCAD) put in the book engine compartment. It totally fits, better than an overhead cam V6 would for sure, and with less piping, cooling, oil lines, coolant lines, and general ***ery than a turbo setup.

The only downside to your setup is the automatic transmission. In a car like this, banging through the gears and ripping up tires is most of the fun! I'd be looking long and hard at the G6's F40 6-speed manual, it bolts right up.

I've gone back and forth on that. I do indeed miss my 6-speeds (years and years of F-bodies and vettes). However, maybe it's just the getting older, but I'm not violently opposed to it being an auto like I used to be. I will probably use the drivetrain as is and then work towards the 6-speed conversion. I understand there are lots of Fiero LS4 6-speed conversions that I can look to for advice. Having done an auto-manual swap on other vehicles before I know how much work that will be, but that's part of the fun I think.

Also it has been interesting to strip the Impala. I thought it would be tedious work that I had to force myself to do, but instead I have really enjoyed it. It basically has to be gutted completely to get all the wiring harness. Maybe that's just me though - I like butchering my own meats as well. Now to start the basic measurements and planning for metal. The engine cradle itself took maybe 1.5 hours to remove - as in if I JUST had to pull that I think it would have only taken me that long. The rest of the body stripping probably more like 12+ hours.


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PostPosted: November 21, 2017, 1:29 pm 
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The 4T80 and its descendants are rather heavy. On the other hand, it's "free", already mated to the engine and computer, the axles fit, all it needs is a single simple shift cable (or have they gone electronic now?) and you can always change to a manual after you get the car rolling.

I drove a friend's 6-speed Corvette for a while. I wound up shifting it as a three speed; 1-3-5. For normal traffic there was no reason to row it through all the gears. For that matter, I did a number of V8 swaps into small foreign sedans back in the day; a small block and four speed in, say, a German Capri, and you only needed second and fourth gear in most situations. First if starting on a hill, third almost never. The torque spread made more than two gears redundant.

There never really was any question of *needing* to row the gears; with the street tires available then, I didn't even have to downshift to smoke the tires at 40mph. Though I admit tires are *much* improved now, and I suspect a sporty modern street tire is better than the race rubber we had in the 1980s.

My first-gen RX had a small block and an automatic; track days at Memphis Motorsports Park, it shifted up to high and stayed there, the track being fast enough there was never any need for a lower gear.

Not trying to persuade you that an auto would be "better", for whatever values of "better" you consider, but that your time and money might be more usefully invested in other parts of the build.


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PostPosted: November 21, 2017, 1:44 pm 
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TRX wrote:
The 4T80 and its descendants are rather heavy. On the other hand, it's "free", already mated to the engine and computer, the axles fit, all it needs is a single simple shift cable (or have they gone electronic now?) and you can always change to a manual after you get the car rolling.

I drove a friend's 6-speed Corvette for a while. I wound up shifting it as a three speed; 1-3-5. For normal traffic there was no reason to row it through all the gears. For that matter, I did a number of V8 swaps into small foreign sedans back in the day; a small block and four speed in, say, a German Capri, and you only needed second and fourth gear in most situations. First if starting on a hill, third almost never. The torque spread made more than two gears redundant.

There never really was any question of *needing* to row the gears; with the street tires available then, I didn't even have to downshift to smoke the tires at 40mph. Though I admit tires are *much* improved now, and I suspect a sporty modern street tire is better than the race rubber we had in the 1980s.

My first-gen RX had a small block and an automatic; track days at Memphis Motorsports Park, it shifted up to high and stayed there, the track being fast enough there was never any need for a lower gear.

Not trying to persuade you that an auto would be "better", for whatever values of "better" you consider, but that your time and money might be more usefully invested in other parts of the build.

I agree with most everything here, and that's why I plan on the first iteration using the combo as is. However, the other concern with the 4T80 is a relative lack of durability, so when (not if) it grenades, I will look to a 6-speed upgrade.

And yes, it is still cable shifted.


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PostPosted: November 21, 2017, 3:56 pm 
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Modern day automatics are quite robust and the automatic does eliminate a bit of operator error.

For an autocross track you don't use many gears and the torque converter actually is a big help.

A track car does use the gears. If you can retain the throttle blip feature then you don't have the big, back end loosening, engagement that you had with the older autos and since the automatic is so common and easy to find I say go for it.

It should make things easier and cheaper.

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PostPosted: November 24, 2017, 1:46 am 
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On the subject of strut rear suspension - there's plenty that can be done to get good outcomes with struts. The Lancia Stratos rally car used a Ferrari Dino drivetrain (i.e. transverse V6 etc) but with strut rear and was quite a successful car. Here's a pic of the chassis with the rear bodywork off:
Image

I'm building a midi with a strut rear - Corolla front struts, shortened and with Koni adjustable inserts. My build diary is at http://locostusa.com/forums/viewtopic.php?f=36&t=3241

I say just go for it - should be heaps of fun.

Dominic


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PostPosted: November 24, 2017, 11:32 pm 
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It seems to me that camber gain on the rear isn't nearly as important as on the front so a strut rear end, while not the bees knees, should be adequate. Everything is a compromise as we've all learned.

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PostPosted: November 26, 2017, 11:23 am 
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jonota wrote:
the other concern with the 4T80 is a relative lack of durability


Well, kindasorta. The usual problem is the soft shift. That puts a lot of heat into the clutches, which get glazed and then start chunking.

You can do some tweakery with the ECM programming to firm up the shifts, and if/when the transmission needs service, it will respond to the usual heavy duty modifications - reducing the clutch pack clearance, some oiling improvements, clutch materials, etc.

I've done several T350s, including the one in my daily driver and the one in a friend's big block Impala drag car, with over 400 passes on it now. I'm not a Real Transmission Expert, but it's not rocket surgery.

A while back I had plans for a build using a 4T60, bought the service manuals, and got familiar with their innards. The T series boxes have a chain and the differential, but otherwise parts is parts.

*If* the transmission fails somehow *and* you don't just replace it with a junkyard box, the transmissions are modular and come apart in easily-serviced chunks. You need to make a few compressors and pullers, a few minutes' welding for a Locost builder. Most of the bits only go together one way, and nowadays a digital camera will let you document each bit and where it goes.

I might be going on a bit, but I avoided transmission work for years, blinded by the FUD of looking at complicated hydraulic diagrams and pictures of what looked like thousands of gnarly bits. It's nowhere near as complex as it looks. Trust me, if you can weld up a Locost chassis, you can rebuild an automatic transmission if you ever need to.


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PostPosted: November 26, 2017, 4:41 pm 
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I will make it work with the struts in the back for the first iteration. I plan on eventually going to all C5 vette suspension.

The 4T65E that is in the LS4 cars is widely known to be quite weak, even pitted against the stock LS4. I know that it can be built stronger, and that will be evaluated when it does fail. Of course, it will be against the cost of the 6-speed swap.


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PostPosted: December 1, 2017, 9:30 am 
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Slight change in plan. Obtained C5 front and rear suspension, steering, brakes, and subframes for a song....now for more research....


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PostPosted: December 1, 2017, 10:27 am 
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Back to the drawing board.....

You will discover now that the reason struts were used with the sideways motor is that packaging becomes a problem, the motor and trans takes up the space needed for upper control arms.

Now you need a corvette or porsche trans axle and you can put the motor back in front and balance out the car.

Or a standard rear center section and put the trans on the back of the motor.

But isnt the Corvette stuff kind of heavy for a Locost?

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PostPosted: December 1, 2017, 1:54 pm 
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Bent Wrench wrote:
Back to the drawing board.....

You will discover now that the reason struts were used with the sideways motor is that packaging becomes a problem, the motor and trans takes up the space needed for upper control arms.

Now you need a corvette or porsche trans axle and you can put the motor back in front and balance out the car.

Or a standard rear center section and put the trans on the back of the motor.

But isnt the Corvette stuff kind of heavy for a Locost?


Corvette pieces are big and heavy. They are way overkill for a Locost style car. The up side to that, is that they don't wear out at the rate they do in a Corvette. Corvettes are known to eat wheel bearings when used on a track, as well as rotors and calipers. The rotors crack and the calipers flex and eventually spread. My car uses all C5 control arms and brakes. Weight without me is around 2100 pounds, so about 1000 pounds lighter than a stock Vette. The bearings and brakes last something like 5-10 times longer than an a Corvette. That's important from a cost stand point because the Vette stuff is also expensive (pads, rotors, and bearings). The top end SKF wheel bearing is about $380 each. On my car I can use the Timken $150 bearing and it still lasts longer than a SKF bearing in a Corvette.

Laminar
Would you mind sharing the link to the LS model? I've looked over GrabCAD and found a block, but not the complete engine.

Thanks
Ken


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PostPosted: December 1, 2017, 4:31 pm 
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I'm going to be heavier anyway, so I think that being a bit beefier will help. I still think I should be able to use the auto. Seemed to work for this guy:
https://www.youtube.com/watch?v=m_aVLRuOg_o&t=2s

I'm basically going the "easy" route for the time being and using sub-assemblies to speed up the initial build process. I plan on "redoing" the car several times if I have my way.

Jon


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PostPosted: December 12, 2017, 5:47 pm 
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BB69 wrote:
Laminar
Would you mind sharing the link to the LS model? I've looked over GrabCAD and found a block, but not the complete engine.


See if this works for you:

https://grabcad.com/library/gm-ls1-ls2-ls3-engine-1


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