3:45's vs 4:10's MPG

[Hammer]

For those out there that have made the switch from 3:45's to 4:10's, what kind of gas mileage change have you seen?

I'm driving to BG in May from Idaho and don't want to swap the gears right now if I will see a drastic drop in mileage. That could add substantially to the trip cost.

Thanks

[DaveK]

I have 4.10s and usually get around 25/26 on the highway. Depends on the weight of your foot though too :)

[Jagdpanzer]

Not seen much of a difference after installing 4.10s in my case.

[HAWAIIZR-1]

Just do it.................. You'll enjoy your drive and get to use 6th gear. :cheers:

[flyin ryan]

I have 4.10s and usually get around 25/26 on the highway. Depends on the weight of your foot though too :)You like/love the 4.10's Dave?

[DaveK]

You like/love the 4.10's Dave?

Mine had the 4.10s in when I got it so I don't really know the 'other side' but it sure moves with the 4.10s!

The gearing feels 'right' for the car and pulls like a demon. Not based on any direct knowledge but I suspect the standard gearing was selected from more of an emmisions/economy goal than actual perfromance.

I'm certainly more than happy with the 4.10s and have no plan to change.

[Hammer]

Well, once again, thanks for all the comments. I'm just gonna do it. Speedo gears on the way from Marc.

[GrayZ]

Don't do it JOHN, :-D it'll probably cost you at least $26.75 extra in fuel, besides making 6th gear useful, is well, way overated...:dontknow:

[Hammer]

Mopar P5007043 viper gears, from where :icon_ques
http://www.trademotion.com/auction/index.cfm?siteid=214650&catalogid=0 (http://www.trademotion.com/auction/index.cfm?siteid=214650&catalogid=0)
Call Jeromy for prices, under $300 shipped.

[Hammer]

Why are the ARP studs being used?
have there been problems with the bolts? I know they are 20 years old but there are billions of cars with bolts running around.

Does the extra clamping force offered change the setup at all?

[Dynomite]

Why are the ARP studs being used?
have there been problems with the bolts? I know they are 20 years old but there are billions of cars with bolts running around.

Does the extra clamping force offered change the setup at all?

Jagdpanzer said do it and HAWAIIZR-1 did it :mrgreen:

I am assuming you are assured full depth of the stud. Once stud is set you get full locking of the nut. One other advantage.....you are not turning the stud while applying the final torque on the nut.

These ARP studs would work great for Head Bolts to obtain more even torque. Does anyone use these ARP type studs for head bolts?

[flyin ryan]

Why are the ARP studs being used?
have there been problems with the bolts? I know they are 20 years old but there are billions of cars with bolts running around.

Does the extra clamping force offered change the setup at all?Studs are obviously the preferred method, no disputing that, right? But I didn't bother with mine, ...unless a person is going to the ¼ mile often with good (sticky) tires, factory bolts are fine. If you want to do it, just because, only really need to the one side. The one cap takes all the load, other side is more or less along for the ride. Also if a person does convert over to ARP studs, better be absolutly sure to have the 'New' correct TQ. spec. & what lube to use. Another thing...Don't 'Double-Nut' the stud in tight to the case...Finger tight only into the case....VERY important!!

[Dynomite]

Don't 'Double-Nut' the stud in tight to the case...Finger tight only into the case....VERY important!!

Why would you "Double-Nut" the stud when it has an allen head?
Just bottom tap the hole like Jagdpanzer suggests and run the stud in with an allen head wrench snug fit.Then apply ARP Moly lube to the nut and torque it down using ARP torque recommendations.

[Jagdpanzer]

I converted to studs because stock bolt holes are threaded into the aluminum housing material without the benefit of inserts and I was worried the threads were not up to taking several disassembles and re-torques for adjusting the shims several times in order to find the optimum gear contact pattern and proper backlash. In my experience in addition to being more secure the studs makes the set up process go a lot smoother and quicker as compared to using the original grade 5 bolts. Your mileage may differ.

[HAWAIIZR-1]

OK already :D

I need Ratech 'Deluxe' Install kit-3012K from http://ratech.stores.yahoo.net/coax84d44.html

Mopar P5007043 viper gears, from http://www.trademotion.com/auction/index.cfm?siteid=214650&catalogid=0 Call Jeromy for prices, under $300 shipped.

Marc Haibeck 13/43 speedometer gears from http://www.zr1specialist.com/HAT%20Web/products/Speedometer%20Correction%20Gears.htm

I convert the carrier caps from 1/2" bolts over to 1/2' ARP studs. ARP Part Numbers:
4 x Stud - AR4.060-LB
4 x Hex Nut - 200-8607
4 x Washer - 200-8514
To order I call ARP Order Desk & Technical Support: 800.826.3045
Use a 1/2"-13 bottoming tap to deepen the threads.

As long as I am there under the differential, I get a Denny's Driveshafts 1350 kit for C4 aluminum half shafts from http://www.dennysdriveshaft.com/p422...build_kit.html

Is that all correct :icon_ques
Is there anything else I will need :drunken_s
I already installed the differential drain plug from Corvette Central
http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000050f~Z5Z5Z5AAUDT~ P66.95~~~~S2U50N0HXI13113113132a~Z5Z5Z5~Z5Z5Z50000 050F

To permanently stop rust I use POR-15 Stirling Silver and Gloss Black paint
http://www.por15.com/POR-15-Rust-Preventive-Paint/products/1/

Are you going to consider rebuilding your posi unit? I only did it because I did not know the history and the mileage was only 53K but when I looked at the clutches once apart I am glad I did. If so, you will want Spicer # 707018X and here is a good source: http://www.drivetrainspecialists.com/categories/dana/dana-44/products/product-446.html Many others sell it, but this was the best price that I could find.

As for the POR-15, no rust on the aluminum but I wanted to clean it up and it did not look very good after my other attempts. POR-15 is just an excellent product that I have been using for over 20 years and it is very durable as it will seal the aluminum from corrosion or discoloration. The yokes on mine were quite rusty and why I used it on that portion. If you are a purist/NCRS type then you will want to keep it all naturalllllll...........

[flyin ryan]

Why would you "Double-Nut" the stud when it has an allen head?
Just bottom tap the hole like Jagdpanzer suggests and run the stud in with an allen head wrench snug fit.Then apply ARP Moly lube to the nut and torque it down using ARP torque recommendations.My point being don't set the stud in too tight! Double Nut/Broached top...tish-tosh :rolleyes:. Finger tight is the way. If it doesn't go in cleanly with your fingers, run a tap or thread chaser through. Applies for all/everykind of studs.

[Dynomite]

Are you going to consider rebuilding your posi unit? If so, you will want Spicer # 707018X and here is a good source: http://www.drivetrainspecialists.com/categories/dana/dana-44/products/product-446.html Many others sell it, but this was the best price that I could find.

As for the POR-15, no rust on the aluminum but I wanted to clean it up and it did not look very good after my other attempts. It will seal the aluminum from corrosion or discoloration. The yokes on mine were quite rusty and why I used it on that portion.

Thanks for suggestions on rebuilding the posi unit. I added Spicer # 707018X to my list in post #10 :thumbsup: and I understand the use of POR-15 for rust. POR-15 on the aluminum housing of the differential does look great however :cheers:

My point being don't set the stud in too tight! Double Nut/Broached top...tish-tosh . Finger tight is the way. If it doesn't go in cleanly with your fingers, run a tap or thread chaser through. Applies for all/everykind of studs. I understand on cleaning the threads and not too tight on the studs after you mentioned it :thumbsup: and I am thinking like Jagdpanzer suggests on rational for using ARP studs as well as using a 1/2-13 bottom tap :cheers:

I converted to studs because stock bolt holes are threaded into the aluminum housing material without the benefit of inserts and I was worried the threads were not up to taking several disassembles and re-torques for adjusting the shims several times in order to find the optimum gear contact pattern and proper backlash. In my experience in addition to being more secure the studs makes the set up process go a lot smoother and quicker as compared to using the original grade 5 bolts. Your mileage may differ.

As always I stole information from other great theads so all the technical information is in one subscribed thread location :thumbsup:

The sources provided by everyone (updated) for parts to install 410s are all in post #10 in this thread.

I put all the 410 information in Hammer's thread herein because gas mileage is always an issue with 410s. Not much is said for the best rational for switching to 410s (sixth gear becomes usefull at speeds under 75 mph) :D

Also, when Hammer installs his 410s I am hoping he will add pictures and suggestions here in this thread since he should now be convinced to install the 410s before BG. It will be interesting how Hammer shims and sets backlash to get that perfect contact pattern as HAWAIIZR-1 ended up with on his 410s (post #40). http://www.zr1.net/forum/showthread.php?t=7419&page=4

Rarely there are some issues related to over spinning the output shaft on the transmission with 410s which ZFdoc at billb@zfdoc.com has explained in detail on another forum. http://forums.*************.com/c4-zr-1-discussion/2522758-wow-the-zfdoc-is-a-great-find-2.html

The ************* do not mean X-rated which I just do not understand the use of ***********

[flyin ryan]

The only time any amount of torque is acceptable on stud run in/bottoming is if the stud has a 'Bullet/Ball' end on the coarse end & the receiving hole has been machined accordingly, female round bottom on blind end, even then, TQ. should be no more than 100 'Inch' Pounds max, for anything automotive size. A lot of guys I see daily run in studs tight [-X, they don't understand, a stud that is set tight will never center properly when the nut is TQ'ed & has 'Pull' applied. True story :).

[HAWAIIZR-1]

Dynomite,

Thanks for your comments and for always sharing your input. I just wanted to let you know that the gear pattern on mine has been questioned by few as not being ideal and the pictures don't accurately show it too. I went back to the installer to question it and the preload he designed into it. He swears by it and will stand by the install from a shop with a good reputation and great owner so I'm going to take a chance on it; I'll assemble mine this weekend and reinstall. The guy built a lot of diffs for race cars and 4 X 4s so I hope all will go well when I break in and run it. Break in will be with conventional gear oil then changed to synthetic after about 500 miles ensuring posi additive each time. When I rebuilt the posi clutch packs we assembled with posi additive from the General.

As for the POR-15, I am not sure of long term effects when used on aluminum yet as this is the first time I am using it on other than steel, but I have loved it in all other uses and restorations with permanent results. I did a lot of research on it with POR-15 tech and websites with info including a guy in Australia that used it on a motorcycle engine. Therefore I am using it on my LT5 block as well as many other aluminum suspension parts too for adding detail while I rebuild everything. I just could not stand to see the ugly, old finish when redoing something. Just be sure to use the prep if so as with any finishing, preparation is the key to a good bond, etc. I used foam brushes that seemed to work for the best finish and will powdercoat the driveshaft and halfshaft in brilliant silver like my top half of motor as I did not want any brush marks on the smooth surface. Although I have a compressor and spray gun, I did not want to attempt spraying POR-15 anywhere since it really is permanent if you don't clean it ASAP. The trans will be cleaned up with Eagle One aluminum wheel etching only per recommendation of the ZF Doc.

Sorry John to pollute your thread with my thoughts unrelated to your MPG question. Just trying to answer the Dynomite since he is a very detailed person. :cheers:

[Dynomite]

Sorry John to pollute your thread with my thoughts unrelated to your MPG question. Just trying to answer the Dynomite since his is a very detailed person. :cheers:

:sign10: I know why you said that Craig....I deleted details I posted in your LT5 engine pull thread related to camshaft timing after BlackWidow#2 asked about an explanation of your low compression on one bank. http://www.zr1.net/forum/showthread.php?t=9180&page=9 (http://www.zr1.net/forum/showthread.php?t=9180&page=9)

After I posted that camshaft timing details in your thread I thought.....what a smart-aleck I will appear to be...so I deleted those couple posts :sign10:

Actually if I use that logic, I will prolly delete a lot of my posts :D
I doubt John (Hammer) will mind us on a tangent here :cheers:

And yes.......I learn from the details.

Thanks for the explanations regarding 410 set up and POR-15 :thumbsup:

Cliff

[HAWAIIZR-1]

:sign10: I know why you said that Craig....I deleted details I posted in your LT5 engine pull thread related to camshaft timing after BlackWidow#2 asked about an explanation of your low compression on one bank. http://www.zr1.net/forum/showthread.php?t=9180&page=9 (http://www.zr1.net/forum/showthread.php?t=9180&page=9)

After I posted that camshaft timing details in your thread I thought.....what a smart-aleck I will appear to be...so I deleted those couple posts :sign10:

Actually if I use that logic, I will prolly delete a lot of my posts :D
I doubt John (Hammer) will mind us on a tangent here :cheers:

And yes.......I learn from the details.

Thanks for the explanations regarding 410 set up and POR-15 :thumbsup:

Cliff

Hi Cliff,

I did not take any offense to your posts and like the fact that you are very detailed and mention or bring up things not mentioned otherwise. Yeah, I don't think Hammer will mind because we are discussing related issues to his gear replacement so all is good I'm sure. I don't know a lot and learning every day, but I like to share anything I can as some feel like there are secrets out there. Thanks again for your input.

Aloha!