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| LS4 / F40 swap - fieroguru (Page 129/216) |
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fieroguru
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JAN 27, 05:15 PM
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It has been 50 degrees the past 2 days and most of the salt was washed away with rain last week, so it was a great opportunity to get the LS4/F40 Fiero out and put about 50 miles on it running around time.
I really like driving this car! Just a few months months and it will take over the daily driving duties from my truck.
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Rickady88GT
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JAN 27, 08:41 PM
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And more updates,...YESSS
I have a blast in mine too, I know the feeling. I just have more "good days" for driving than you do 
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Will
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FEB 01, 09:02 PM
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| quote | Originally posted by fieroguru:
Most dynos are ran in whatever gear gets it closest to 1:1 ratio. So your LS4/4T65 should have been dyno'd in 3rd gear. I dyno'd my LS4/F40 in 4th gear (151 mph @ 7000 rpm).
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That's a holdover from longitudinal RWD domestic cars, as 4th gear isn't just 1:1, it's "direct", in that the power flow is straight from the input shaft to the output shaft with essentially no friction from gear meshes. In a transmission without a "direct" gear, the gear that results in the highest number would be the one that strikes the best balance between the parasitic loss of accelerating the flywheel and the parasitic loss of accelerating the wheels & tires. In fact, a transmission WITH a direct gear may not necessarily make the highest numbers in direct.
| quote | Originally posted by fieroguru:
If you wanted to make 3rd - 5th less long, you can swap in the short gear ratios for each and end up with this combo:
code:
Tire Dia RPM 1st 2nd 3rd 4th 5th 6th
24.9 6000 38 70 105 137 170 232
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That's what I'm going to do, in addition to a custom 1-2 set.
Have you come across a part list for the F40? I'd like to find the part numbers for the 0.62 sixth gear pair. I'd be annoyed to have to buy an entire transmission to snag the second set of that ratio that I'm going to need.
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Rickady88GT
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FEB 07, 12:35 AM
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| quote | Originally posted by Will:
That's what I'm going to do, in addition to a custom 1-2 set.
Have you come across a part list for the F40? I'd like to find the part numbers for the 0.62 sixth gear pair. I'd be annoyed to have to buy an entire transmission to snag the second set of that ratio that I'm going to need. |
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Yes, more transmission mods
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Will
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FEB 07, 09:32 PM
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I want to build a custom box for the Northstar car, but I have the MU9 unit with 3.55 gears from an '06 Saab 9-3 with high feature V6. An LLT, LFX or LGX will bolt right up to it. However, being an MU9, it has the 0.71 sixth... which is not nearly as good at what it should be doing as the 0.62 sixth. It would be super sweeeeeet if I could find the part numbers and buy those gears to swap them into that box... without having to buy an entire MT2 box to get the gear pair.
BUT... if they're more expensive than buying a transmission, I'll have to think about that.
I guess I need to find the nearest Saab dealer for a field trip.
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FieroWannaBe
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FEB 08, 04:15 PM
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| quote | Originally posted by Will:
I guess I need to find the nearest Saab dealer for a field trip. |
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Do such places still exist?
Maybe a Fiat dealer?
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wftb
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FEB 08, 05:51 PM
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There are no dealers of new Saab automobiles anywhere on the planet. GM closed Saab for good.
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fieroguru
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FEB 08, 06:55 PM
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The parts numbers are iffy on most of the documents. For example a MYJ with the 3.55 I know the 6th gear part # on the input shaft, but the same document didn't show the corresponding part number for the 6th gear on the lower main shaft. It also shows the ring gear part #, but not the part numbers for either main shaft.
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Will
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FEB 08, 08:41 PM
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fieroguru
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FEB 08, 10:55 PM
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AC Delco 12787428 for the input shaft 6th gear, but I am not certain this is for the 0.62 ratio. CariD does list the specs for this gear, so with some work the ratio could be confirmed.
Nemiga.com used to list a couple of F40 component diagrams for the Opel and Vuxhall with the part call out descriptions as well as some part numbers, but now it looks like their catalog section isn't working (good thing I copied the info to excel and saved it).[This message has been edited by fieroguru (edited 02-08-2018).]
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