Building a new 8.8 end to end

[blacksheep-1]

I personally think you are going the wrong way on gearing, I would recommend at the minimum a 3.90 to 4.10 (NOT 4.11, but 4.10) when you say you have small tires that work with the 3.15, I have to point out something the dragster guys figured out in the mid 70s. Tire traction is not only measured in tire width, but also in tire diameter, the tire deforms as it compresses under vehicle weight, the diameter comes into play, a taller tire will yield a much bigger footprint than a smaller one, even though they are the same width. To run a 3.14 and a short tire, is a false economy, IMO.

 

[twistedneck]

I personally think you are going the wrong way on gearing, I would recommend at the minimum a 3.90 to 4.10 (NOT 4.11, but 4.10) when you say you have small tires that work with the 3.15, I have to point out something the dragster guys figured out in the mid 70s. Tire traction is not only measured in tire width, but also in tire diameter, the tire deforms as it compresses under vehicle weight, the diameter comes into play, a taller tire will yield a much bigger footprint than a smaller one, even though they are the same width. To run a 3.14 and a short tire, is a false economy, IMO.

I agree w everything you said.. keep in mind i'm sticking with the the Getrag not the Tremec. Liberty is getting good at building them and they are right down the street.. I realize at some point i'll need to take the bigger step to the Tremec but I like this little MT82, I already have a wicked cf drive shaft setup for it, and I have a very light single plate clutch.

As you know, gearing on the Getrag is made for a euro hauler van as such a 3.15 is needed for me to support the standing mile w a 26-27" tire @ 180-185 mph in 5th (1:1).

That's why I use a 25" drag tire, to enable me to fish the 1/4 mile with this gear setup about 6800-7000 rpm @ 122mph. hoping for 125 next year.

in previous postings seca954 explained that if you want to keep the ABS - we need to stick with 31 spline axles - he recommended Moser and that sounds fine.

Regarding Ford 9" ends vs stock 8.8, LikeABauce302 confirmed those are needed as 'C clip eliminators' and required by NHRA for 10.99 and quicker. I'm not going to swap over because I don't drag race enough to have that issue come up and with my NA combo if I do hit 10.99 it will be on a test n tune day not some type of drag competition.

So would you agree that a set of Moser 31 spline axles, Detroit True Trac, Ford racing gears and all new bearings would be a good combo? If so, i'll have to get the long ARP studs. Based on your response on the lug thread, there aint no way I can come up with $1000 just in lugs and a socket!! So best I can hope for is a factory long stud kinda like Vorshlag's kit. I'll respond in the other thread about more detail on that.

Thoughts? Thanks!!!

 

[2013dibgt]

Is there any reason to believe that the Moser 31 Spline Axles are any stronger than the Factory 31 Splines you have already? I haven't heard of many folks snapping the factory axles these days. The Diff seems to let go way before the axles do. Since you;ve already taken care of welding the Tubes to the housing and also already plan to swap in an Eaton Diff I would imagine that would be a pretty stout setup with any slick you intend to run.

 

[302 Hi Pro]

Hi TwistedNeck:

I find your above post pretty interesting, and wonder if you can elaborate on a couple of points/concerns you made.

Can you tell me more about your standing mile runs?

"As you know, gearing on the Getrag is made for a euro hauler van as such a 3.15 is needed for me to support the standing mile w a 26-27" tire @ 180-185 mph in 5th (1:1)."

What do you anticipate your engine RPM's running at 180-185 MPH in 5Th gear with the 3.15:1 rear ratio?

Next is the quarter mile, for some reason I had the impression you are running an All Motor setup and I was wondering what were you running before the rear diff tear down? You stated running 7,000 RPM at 122MPH, (must be 4th gear?), but what were your ET's and 60' times?

"That's why I use a 25" drag tire, to enable me to fish the 1/4 mile with this gear setup about 6800-7000 rpm @ 122mph. hoping for 125 next year."

Sorry if I missed this before, but what are your new goals for ET and 60' times with the new rear diff setup at 125 MPH?

Thank you,
Dave
302 HP

 

[twistedneck]

Hi TwistedNeck:

I find your above post pretty interesting, and wonder if you can elaborate on a couple of points/concerns you made.

Can you tell me more about your standing mile runs?

"As you know, gearing on the Getrag is made for a euro hauler van as such a 3.15 is needed for me to support the standing mile w a 26-27" tire @ 180-185 mph in 5th (1:1)."

What do you anticipate your engine RPM's running at 180-185 MPH in 5Th gear with the 3.15:1 rear ratio?

Next is the quarter mile, for some reason I had the impression you are running an All Motor setup and I was wondering what were you running before the rear diff tear down? You stated running 7,000 RPM at 122MPH, (must be 4th gear?), but what were your ET's and 60' times?

"That's why I use a 25" drag tire, to enable me to fish the 1/4 mile with this gear setup about 6800-7000 rpm @ 122mph. hoping for 125 next year."

Sorry if I missed this before, but what are your new goals for ET and 60' times with the new rear diff setup at 125 MPH?

Thank you,
Dave
302 HP

Dave, thanks for asking.

W a 26" tire, 3.15 gear, 7500/rpm in 5th (1:1) = 184mph. I have yet to make a mile run!! But its in my future.

For the 1/4 25" tire, 1.8/60' , 11.6@122 depending on weather and traction. These NA engines are very sensitive to DA and I'm also no light weight.

After I put on the cortex setup and lithium battery and 3.55 gear it ran 1.72 60' 11.5@120 but I had to let off 100 feet or more from the line I was at 7500rpm redline cause of that new 3.55 gear.

The car is a lot of fun w e85 it moves.. Yes it's NA.

 

[blacksheep-1]

I would go with the Moser axles and leave the stock c' clips in place, let me justify that by saying that I've never seen a Moser break.




if you are going to the trouble of placing 9inch ends on your axles, you might check out Performance Products (distributed by Cortex) that not only allows you to remove the c clips but also to add camber..or not.. depending on your preference. It's an expensive setup but when you start modding the rear you sort of need to go all the way with it. The Moser axles are a reasonable compromise that is not too expensive.
Also you may find smaller diameter studs that work the same as the 5/8 ARP studs that we use.

 

[twistedneck]

I would go with the Moser axles and leave the stock c' clips in place, let me justify that by saying that I've never seen a Moser break.




if you are going to the trouble of placing 9inch ends on your axles, you might check out Performance Products (distributed by Cortex) that not only allows you to remove the c clips but also to add camber..or not.. depending on your preference. It's an expensive setup but when you start modding the rear you sort of need to go all the way with it. The Moser axles are a reasonable compromise that is not too expensive.
Also you may find smaller diameter studs that work the same as the 5/8 ARP studs that we use.

With your 9" ends from cortex do you maintain the abs? 31 or 33 spline? Camber on a solid axle?? That's NASCAR stuff. :'( let the credit card melt!

 

[Swiss Boss]

Here's the product Blacksheep is talking about
http://www.raceproducts.net/900-series-spline-drive-camber-kit/

I've talked to them last year at PRI. Very cool guys. And since then I keep drooling on that setup.
You basically have to cut the end of your axle housing then insert and weld an adapter piece and everything else bolt to that piece.

 

[twistedneck]

Here's the product Blacksheep is talking about
http://www.raceproducts.net/900-series-spline-drive-camber-kit/

I've talked to them last year at PRI. Very cool guys. And since then I keep drooling on that setup.
You basically have to cut the end of your axle housing then insert and weld an adapter piece and everything else bolt to that piece.

$2900 US just for most of the parts.. up to 3 degrees negative camber and you get up to 2 degrees tow in. rear tow in great for coming off corners, and it gets the rear moving going into corners if you have too much understeer. is this allowed in GTS?

 

[blacksheep-1]

It's far superior to just barrel grinding the axle splines and bending the diff in a press NASCAR style, but that is another option. Keep in mind some folks don't run cambered rears, I know of a stock car guy that run positive camber on the left rear on a bump steer car, on ovals

 

[steveespo]

NASCAR guys used to run custom floaters with cambered drive plates until NASCAR banned cambered axles in 2009. They recently allowed rear camber back but using the old heat and bend/beveled spline method that Rob refers too. Saw the setup on Dean Martin's PWC car this May along with the fixed rear brembo calipers. Pretty trick.
Steve

 

[twistedneck]

Moving forward a little more - Looks like you cannot get 31 spline hollow axles - so I'll just use the Moser ones.

Steeda bearing to replace upper control arm rubber bushing.

Light weighted gear with REM polishing (JPC - 3.15 gear).

Here is the new kicker.. CERAMIC BEARING!! yes, its $780 but I've heard from some race engineers that its the cats meow. On top of the reduced friction and heat, you get more wear and less noise. I also going to break the bank and put in the ceramic pilot bearing and all ceramic main bearings in the MT82 (yes, that's an entire tax refund $$). but hell.. i'm out of things to do on my Mustang to save weight and reduce friction / increase speed.

I can't justify a new motor until mine calls it quits, and that could be a few years. Gotta have AC and two really nice speakers and front air bags - so weight has to come off! Damn those rattly k-members. can't go there.

Sorry to get off topic blacksheep-1 .. what are your thoughts on ceramic bearings?? I already have a freakin $800 battery! ah!!

 

[blacksheep-1]

I'm not sure that we used them in our diffs, but when we raced Brand X we used them with good results in the turbos...