Do you have a pic of the engine/oil pan side of the AWD system? Maybe you could run a shaft out through the "front" side via a shaft from the opposite direction (forward rather than rearward)? From the pinion? Use the stock case and push the output shaft through the front from the pinion. A custom pinion might be easier and cheaper than a custom housing that would essentially do the same thing. But then, You may have something in mind that is similar or better.
[This message has been edited by Rickady88GT (edited 03-07-2018).]
1. A custom pinion is likely about $5K. The custom case is probably $500 in materials and 40 hrs of machine work for me. 2. The output shaft would end up passing through the support shaft for the AWD ring gear (See first picture below). 3. The oil pan side is curved with no good/strong way to add the pinion housing to it, especially given the loads that the pinion housing will see.
[This message has been edited by fieroguru (edited 03-07-2018).]
1. A custom pinion is likely about $5K. The custom case is probably $500 in materials and 40 hrs of machine work for me. 2. The output shaft would end up passing through the support shaft for the AWD ring gear (See first picture below). 3. The oil pan side is curved with no good/strong way to add the pinion housing to it, especially given the loads that the pinion housing will see.
I wish I had one in my hands to help, but..... Sorry, I can't tell from the pics, but I am sure you have a good point.
Ok, so let's see if I get this right. The red cap is a splined female output shaft for the rear wheels. That output shaft is the acual pinion gear. IF you were to be able to push the male drive shaft all the way through the pinion, would it come out the other side, or would it interfere with the ring gear shaft? I can't tell from just the pics, but typically the pinion is not on the center line of the ring gear, they are usually just over center or under center.
[This message has been edited by Rickady88GT (edited 03-08-2018).]
Originally posted by Rickady88GT: The red cap is a splined female output shaft for the rear wheels. That output shaft is the acual pinion gear. IF you were to be able to push the male drive shaft all the way through the pinion, would it come out the other side, or would it interfere with the ring gear shaft? I can't tell from just the pics, but typically the pinion is not on the center line of the ring gear, they are usually just over center or under center.
Correct, the red cap is the output shaft connection point and the pinion gear.
It would run right into the support shaft for the ring gear. Here is another picture where I circled the bearing support for the ring gear is in the side case and put another line where the support shaft goes. If you correct for the angle of the picture the pinion and support shaft will intersect and interfere with each other.
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Originally posted by RacerX11: Is the same transfer case used for the manual and the automatics? Marty
I "think" the cases are very similar if not the same, but the passenger side jackshaft that passes through the AWD unit has 2 different part numbers between the Auto and Manual and I suspect the difference is in how far it protrudes past the mounting flange for the AWD unit to the transaxle.
"auto or manual"? I must have missed something somewhere, but that sounds like there is an automatic AWD transmission out there that is transverse? If you figure out how to make that work (auto-AWD in the Fiero).... you know I'll gladly be inline for that.
"auto or manual"? I must have missed something somewhere, but that sounds like there is an automatic AWD transmission out there that is transverse? If you figure out how to make that work (auto-AWD in the Fiero).... you know I'll gladly be inline for that.
There are lots of transverse/auto/AWD setups... just about every crossover SUV on the road has this setup.
Here is the Saab version witth the auto... the issue is everyone of these points the output shaft to the rear.
I have thought about 4wd but it always boils down to is it worth all the work? I don't really know. There is the problem of where to put the driveshaft. Moving the fiero tank will hurt the balance of the car, it is in the perfect spot now. A custom gas tank with a tube in the middle to route the drive shaft through?
As far as it being done before yes there are a lot of hybrid drive trains out there but no one has done one without a battery pack.
There is an exoskeleton rear mid engine/all wheel drive car on the locost forums using I believe Mitsu Evo drive train. I will see if I can find a link, the info is kind of skimpy but maybe you might see something that will give you some more ideas.
You will also need to flip the front differential.
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Originally posted by fieroguru:
Correct.
Depending on the shaft rotation direction, you may just run the front diff from an AWD Porsche 996. That has the viscous coupling built into the front axle unit.
I "think" the cases are very similar if not the same, but the passenger side jackshaft that passes through the AWD unit has 2 different part numbers between the Auto and Manual and I suspect the difference is in how far it protrudes past the mounting flange for the AWD unit to the transaxle.
Spur gear to offset downward, then spiral bevel to transfer to rear driveshaft?
Originally posted by Will: Soooo.... Is the bevel set a spiral bevel or hypoid bevel? If hypoid and you turn it around, the shaft will end up higher, which may interfere with your crankshaft...
I haven't had any free time to mess with it, but I assume it is a hypoid with a small offset from the the ring gear center line. So when I flip it 180, its vertical placement won't change much.
just a thought that might help with packaging, how about a drive cable instead of a shaft, probably not super efficient, but I would imagine it's possible.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
The center-line of the pinion gear is about 7/16" lower than the center-line of the ring gear, so flipping it 180 will raise the output shaft about 7/8". That will place it about 3 5/16" below the F40 axle center-line. The F40 axle center-line is about 2 13/16" below the crankshaft center-line, so centerline to centerline between the AWD output shaft and the engine crankshaft should be close to 6 1/8"... which means the output shaft should have room to clear the crankshaft.
Some other important info: Splines on passenger side intermediate shaft: 27 Splines on AWD power takeoff from differential: 38 Gear teeth on hollow drive tube: 35 Gear teeth on ring gear shaft: 26 Gear teeth on actual ring gear: 31 Gear teeth on pinion gear: 15
Overall ratio has the pinion output shaft spinning 2.781 times faster than the F40 differential RPM.
I still need to collect a F40 AWD differential with the female spline shaft to drive the AWD unit as well as the front differential.
The center-line of the pinion gear is about 7/16" lower than the center-line of the ring gear, so flipping it 180 will raise the output shaft about 7/8". That will place it about 3 5/16" below the F40 axle center-line. The F40 axle center-line is about 2 13/16" below the crankshaft center-line, so centerline to centerline between the AWD output shaft and the engine crankshaft should be close to 6 1/8"... which means the output shaft should have room to clear the crankshaft.
Some other important info: Splines on passenger side intermediate shaft: 27 Splines on AWD power takeoff from differential: 38 Gear teeth on hollow drive tube: 35 Gear teeth on ring gear shaft: 26 Gear teeth on actual ring gear: 31 Gear teeth on pinion gear: 15
Overall ratio has the pinion output shaft spinning 2.781 times faster than the F40 differential RPM.
I still need to collect a F40 AWD differential with the female spline shaft to drive the AWD unit as well as the front differential.
Is there any reason for the hollow shaft of the ring gear? Does anything run through it? I understand that the larger diameter of the bearing shaft is better, but is that hollow used for anything?
What are the differences between the Saab and F40? Are there differences between the auto and manual?
Saab was the original application for the F40 (so there are Saab F40s, just like Pontiac G6 F40s and Buick Regal F40s). Saab's 6 speed auto is called AF40 and the AWD units between the Auto and Manual versions are very, very similar. In stock configuration they might not be interchangeable, but since I am making a new case for mine, everything should be able to be "made to work". The Saab AF40 AWD units are much more plentiful and cost less. The one I am tearing apart was $250 shipped.
Yes, there are differences between auto and manual. The intermediate axle shaft is one for sure (different GM part numbers), but it has the proper splines to engage the F40, so it might just be a length issue, but I am redesigning the case and make adjustments for any length issues. There may be other differences that I haven't figured out, but with my intent of making a custom case, I don't think they are significant.
The bolt pattern between the AF40 AWD unit is the same as the European unit, but there are 2 interference areas. The center boss on the AWD unit is larger than the axle seal hole in the F40, so the F40 case will need to be bored. While doing that, I will need to clearance the bellhousing case about 1/8" as well:
It looks like the bolt hole that is centered inside the hollow ring gear shaft is the same between the AF40 an the G6 F40 case, but that is the only common bolt hole. There is a raised boss on the G6 F40 that is in the way, also right now the LS4 oil pan flange and the AWD case interfere by about 1/4". All should be able to be addressed with a new AWD case half. The AWD unit also sticks below the LS4 oil by by about 3/4".
The AF40 passenger side intermediate shaft is 1 1/8" longer than the cobalt SS intermediate shaft. This is very good. When I first did my LS4/F40 swap, I lengthed the Saab intermediate shaft (same as the cobalt one) by 1 3/8" so I could use the stock G6 axle shaft on the PS. This means this intermediate shaft will work with my current axle setup.
I took them apart to repack the bearings with mobile 1 synthetic grease, so I took a picture of the flange shaft of the new bearing vs. an OEM 88 one.
The bearings are all back together now and I am waiting for the paint to dry... I might even get around to installing them on Sunday.
I also installed some 2014+ 18" Silverado wheels on my Colorardo. I had to bored the centers to fit the enlarged Colordado hub. Now I need some lower profile tires and drop the truck about 3" (yes, lowered 4x4...)
It looks like the bolt hole that is centered inside the hollow ring gear shaft is the same between the AF40 an the G6 F40 case, but that is the only common bolt hole. There is a raised boss on the G6 F40 that is in the way, also right now the LS4 oil pan flange and the AWD case interfere by about 1/4". All should be able to be addressed with a new AWD case half. The AWD unit also sticks below the LS4 oil by by about 3/4".
Took the passenger side axle shaft out of the AWD unit. It is interesting as one end is male and one end is female. The really nice thing is it is just the right lengths to be used with a stock G6 driver side axle (with the CV end swapped to the Fiero CV).
I also took the pinion gear out of the bearing housing cap. The pinion housing is hollow with female splines for the drive shaft to attach to.
I started to test fit the gear shafts to the engine and transmission and quickly found another interference issue. The excess flange on the oil pan interferes with the gear. Interesting that the pan has a notched area show and that is what I need to remove for the gear to clear.
Once the oil pan was clearanced, I made some crude bushings so the gear shafts would center on the passenger axle as well as a long bolt that is threaded into the common hole at the gear shaft center.
I need to remove the oil pan on the mockup engine to test fit the pinion in the forward facing position.
As I read this AWD section for the second or third time I see a separate gear case to move the output farther towards the passenger side. Sort of a transfer case. It would keep it simple I think.
You could use 2, 3, or 4 gears depending on how far, and the direction of rotation you need to clear the AWD unit and the engine sump. Angle it up or down a little if needed. Bolt it on over the pinion support, using the 7 AWD pinion support bolts. And with a bracket on the output end.
This way you could adjust the ratios to work with whatever you find for a front diff.. 50:49 will give 2% over drive I think. This gives you more options. More easily replaced if damaged.
Best of all separate cases could be put in your store for hill chimers, rally, off road, kit-cars, and so on.
Originally posted by fierogt4e: As I read this AWD section for the second or third time I see a separate gear case to move the output farther towards the passenger side. Sort of a transfer case. It would keep it simple I think.
You could use 2, 3, or 4 gears depending on how far, and the direction of rotation you need to clear the AWD unit and the engine sump. Angle it up or down a little if needed. Bolt it on over the pinion support, using the 7 AWD pinion support bolts. And with a bracket on the output end.
This way you could adjust the ratios to work with whatever you find for a front diff.. 50:49 will give 2% over drive I think. This gives you more options. More easily replaced if damaged.
Best of all separate cases could be put in your store for hill chimers, rally, off road, kit-cars, and so on.
AWD Fiero! That's just cool.
P.S. Slam that 4X4!
Simple is a matter of perspective. My plan is to use an off-the-shelf AWD unit, then make a new case where I can reuse the off-the-shelf gear set in the custom case. That way I only have to make 1 part (albeit with a significant amount of machining required), but the bearings, gears, shafts, and output housing will all remain stock. In the event I frag a gear, then I just need to pick up another $250 awd unit to get a replacement part.
I doubt this would ever be a product I "could" sell... just not that many people running F40 transmissions in Fieros, even fewer who would want the weight or complexity of AWD, and few still would want to pay for the upgrade that would require an AWD differential, AWD unit, custom case, custom fuel tank to allow room for the driveshaft to the front, front differential, front axles, and custom fab to convert to driven front wheels... With me doing all the work, the first one will likely be in the 3-4K range for the conversion.
It will probably be similar to the 3.09 final drive upgrade. It has been available for 8-9 months with very little interest... But I absolutely love it, so all the effort to do it was well worth it!
Guru, what is the dia of the bolt circle on the LS4 crank?
Joe
3.127". Same as all other LS based engines except the LS7/LS9. The center pilot bore is the same as the 1 piece rear main seal SBCs (2.071"), but the crank pattern isn't the same (but the holes only need some slight slotting - my first prototype used a mid 90's LT1 flywheel).
Spec offers a LS4/F40 flywheel now, so I stopped making them.
If you want to stick with the F23, get a billet steel LS1/LS2 flywheel (they are about 0.81" thick) and turn the OD down to accept the 142 tooth ring gear and drill the Fiero pressure plate pattern.
3.127". Same as all other LS based engines except the LS7/LS9. The center pilot bore is the same as the 1 piece rear main seal SBCs (2.071"), but the crank pattern isn't the same (but the holes only need some slight slotting - my first prototype used a mid 90's LT1 flywheel).
Spec offers a LS4/F40 flywheel now, so I stopped making them.
If you want to stick with the F23, get a billet steel LS1/LS2 flywheel (they are about 0.81" thick) and turn the OD down to accept the 142 tooth ring gear and drill the Fiero pressure plate pattern.
Thanks, This thread is hands down the best source for LS4 info... I am going to take a look at using the flywheel I got from CHRF for my Nstar. Are you aware of any LS4/F23 swaps, my search has only turned up 4t65 auto's and F40's?
I made the decision last night to pull the plug on the Nstar. (Been wrestling with this for a long time, the fact that I can pick up several LS4's locally for less than $500 each helped, that's less than I'll spend to fix the Nstar headbolt issue...) I honestly think I'll get the car up and running sooner and with less hassle going LS4. Am I correct in assuming the LS4 has a 58x reluctor?
Joe
[This message has been edited by motoracer838 (edited 05-27-2018).]
There are a couple of LS4/F23 in the works. There have also been a couple of LS4/200R4s done in longitudinal format.
The 05 and 06 are 24x and the 07+ are 58x.
It was a hard decision to move on from the SBC, but now that I have, I would not do anything else besides an LS swap going forward... they are AWESOME!
" I'm too deep in parts to back up now"... Over the years, I've let this mindset to lead me down the rabbit hole only to wind up dissatisfied in the end or into a dead end that I had to back out of at even more expense, time to change that... And how many Nstar threads end happily??? Not trying to rag on the Nstars, just acknowledging some issues with them... My project started almost by accident, but I've never really got excited about it. (might have a had role in how long the car has sat, easier to let it set than deal with it... )
How much room do you have between the top of intake and bottom of deck lid, I have a Trailblazer ss intake, I'd like to use, but just don't know until I can mock it up. (i know they're ugly but are the best of the oe cathedral port intakes...)
Don't get overly hung up on ideal LS based parts, there are very, very few truly bad parts (stock LS4 intake would be one). The LS1, LS2, LS6 intakes have all been used on 500hp NA builds... so while a dyno will show the TBSS being about 30 lb-ft and 30 hp better than the LS1 on a 6.0L engine spinning to 7K, the difference will be less with the 5.3.
With fieros and available manual transmissions, having some slight reduction in low RPM torque isn't a bad thing.
Focus on what fits, looks good, and is less expensive (which is why I run the LS2 intake).
I could swap to a non-dod camshaft and port the LS2 intake and be over 400 whp...
Just happened to have it on hand for my Silverado, if I ever get to it... My plans are as follows, tell me if you see a problem with any of it. The engines I'm looking at tomorrow are all '06, that gives me the 24x reluctor Dod delete Mild cam, possibly a used LS3 or 6 cam LS2 or 6 intake with a drive by cable tb 0411 pcm, probably start with a stick shift LS1 tune for a starting point, this "should" work for Colorado smog laws, I'll know more tomorrow!!! and a decent exhaust, probably take a page from your book with the LS7 manifolds, I to have had issues with "shorty's" And I don't feel like building headers for this... I'll spend the money where I have to and be cheap when I can...
With nearly 300 ft lbs of torque at just over 2000 rpm's yours must be an insane amount of fun to drive... Joe
[This message has been edited by motoracer838 (edited 05-28-2018).]
I am going to take a look at using the flywheel I got from CHRF for my Nstar. Are you aware of any LS4/F23 swaps, my search has only turned up 4t65 auto's and F40's?
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