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| LS4 / F40 swap - fieroguru (Page 10/216) |
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diabloroadster
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JAN 27, 10:09 PM
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Super build! Love it- love it- love it.....
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mwhite
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JAN 28, 11:48 AM
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KissMySSFiero
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JAN 31, 02:18 AM
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fieroguru
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JAN 31, 06:40 AM
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| quote | Originally posted by KissMySSFiero:
weekend updates??
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Nothing LS4 related has happened... still collecting cash for my next round of purchases (plug wires, clutch, wide band O2 controller, etc). A friend brought over an 88 formula with a 3800SC/Getrag for me to do some work on, so I will need to finish that up before I can get back to the LS4.
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stickpony
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JAN 31, 03:02 PM
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| quote | Originally posted by Will:
GM built a version with 3.94 final drive in the 03-04 Saab 9-3's.
The 1st and 2nd input gears are integral to the input shaft. |
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REHEHEEALLY...
will, do you think the entire gear assembly could be swapped into the g6 speed casing?
this would make an ideal tranny gearing for high TQ v8 manual tranny swap, such as the LS4, assuming a 2nd gear launch, effectively turning it into 5 speed if you ignore 1st gear. the 3.55:1 final in the f40 is too tall to make 2nd gear launches practical, but a 3.94:1 final would work just fine for that application
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KissMySSFiero
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FEB 15, 06:50 AM
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| quote | Originally posted by fieroguru:
I also spent a couple of days turning down a Spec LS1 168 tooth billet flywheel to accept the 142 tooth ring gear. I am thinking about making one LS4/Getrag (92-94 HTOB) flywheel and starter mount and put it on ebay to help fund the LS4/F40 swap...
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You still thinking about selling the flywheel and starter mount?
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SSFiero@Aol.com 87 Gt-5spd-62k miles.
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fieroguru
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FEB 15, 08:59 AM
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| quote | Originally posted by KissMySSFiero:
You still thinking about selling the flywheel and starter mount?
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Yes, it is still a possibility. The flywheel has been turned down, but still needs the ring gear landing and pressure plate pattern added. Then I need to mock up my 92-94 HTOB getrag transmission with the LS4 for the starter pad.
Been bogged down with lots of other stuff the past month or two, but hopefully I will get back to updating this thread in a week or two.
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fieroguru
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FEB 19, 07:25 PM
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Back to working on this swap... finally.
Made the 4 mount tabs for the front side mounts:
For the rear transmission mount, the tabs are slightly modified off the shelf items:
I am planning to have all the engine/transmission mount tabs completed this weekend.
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fieroguru
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FEB 20, 01:38 PM
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It is nap time, so no cutting/grinding in the basement... but a good time to update. 3 of the 4 mounts are done and the 4th one the templates are made.
Here are the two templates for the rear engine mount:
Once the girls wake up from nap, I should be able to make the last two tabs and get them tacked to the cradle.
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fieroguru
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FEB 20, 06:48 PM
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Mounts are done and fully welded. These should hold up to whatever amount of HP I want to throw at them (might run NOS or go turbo at a later date), but are still rubber mounted to reduce shock loading:
While I had the transmission off, I verified a few other items.
For those of you wanting to run a 92-94 Getrag or the F23 transmission behind an LS4, a stock LS1 168 tooth flywheel is just about perfect from a thickness standpoint, then it is just a matter of turning it down to accept the 142 tooth flywheel and drilling the pressure plate pattern. The one I am modifying for R&D purposes protrudes .818" and has been resurfaced 1 time. This is slightly less protrusion than the stock fiero (.830" was the last one I measured). The LS4 ring gear protrudes .826" from the bellhousing and would probably need to be flush with the face of the flywheel.
There has been lots of discussions lately about the proper measurement of the range of travel for the F40 HTOB. So here are the following measurements - all measurements are distance from the Bellhousing Flange:
End of Input shaft: 1.121"
End of Splines: 1.502"
HTOB fully extended: 2.675"
HTOB fully compressed as delivered: 3.218"
HTOB fully compressed with the bleeder screw opened: 3.582
The F40 HTOB has a check valve inside it. So the amount of fluid in the HTOB from the factory is trapped and will not allow the HTOB to fully collapse until the bleeder assembly is installed and the bleeder screw opened. Once you bleed off the factory fill, you get an extra .364" of travel to the back side and the overall range of travel increases to .907" (from .543").
Here is the setup I used to get these measurements with my digital calipers:
A while back I found a 9 7/8" clutch that "should" fit the F40 application. I wanted to use the largest diameter clutch that will fit to improve overall drivablity while still having a clutch that will hold the power. This particular carbon kevlar clutch is rated (for what it is worth) at 461hp/450lb-ft. The pressure plate pattern is not the same as a stock fiero, but I needed to drill the pattern anyway... The good news is the pressure plate clears the inside of the transmission... I still need to bolt it to the flywheel with the clutch installed to check the stack height.
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