BadAss SRT-Z - 2.4L / A568 - Update!!!

[c2xejk]

If the miss is happening under high load, that may be tough to duplicate on the street with street tires.

As for duplicating real world conditions, some of this depends on dyno type... The weighted wheel type, true. For one that can be electronically controlled (ie hold a load/rpm point) you should be able to zoom in on the operating point that causes the problem.

[Aries_Turbo]

just ride the brakes. you can pretty much stall the engine on a good set of brakes creating all the load you need.

[bakes]

The load type dyno is the safetest way to get it to do it and be under the hood probing ciruits and stuff

[Reaper1]

just ride the brakes. you can pretty much stall the engine on a good set of brakes creating all the load you need.

+1

[BadAssPerformance]

Update...

I feel kinda weird, first time the Z has had anything less than 100 octane in it since the 90's!

Completed:
-New programmable fuel level guage installed
-cell topped off with 93 octane
-cig lighter sockets installed

Still need to
-pull out boost controller so it only runs 15psi
-update cal for 93 (thanks for the info DJ!)
-get some street miles on it
-go make a pass or two on 93 (cost less to blow it up close to home)
-wire up trailer wiring
-determine how much crap I need to pack

[Reeves]

Update...

I feel kinda weird, first time the Z has had anything less than 100 octane in it since the 90's!

Completed:
-New programmable fuel level guage installed
-cell topped off with 93 octane
-cig lighter sockets installed

Still need to
-pull out boost controller so it only runs 15psi
-update cal for 93 (thanks for the info DJ!)
-get some street miles on it
-go make a pass or two on 93 (cost less to blow it up close to home)
-wire up trailer wiring
-determine how much crap I need to pack

Your list sounds familiar. LOL.
My fuel level sending unit decided to get stuck again a few weeks ago. I took it apart (this is the third time I believe), and the little magnet had wiggled out of the foam enough to where it was rubbing the circuit board and got stuck in one spot. JB Weld works great. Checked that off the list.
I run 93 most of the time. I only put race fuel in for the track. But I never generally get on it that much on the street (BFGoodrich Drag Radials still spin at 100+mph). I did quite a bit of tuning with 15 to 20 psi on the street this past weekend with about an extra 400 lbs in the car. At close to 20psi boost with 8* base timing, no knock. With 12* base timing, got a tad of knock. Added a single bottle of Lucas Octane Booster to the tank (probably about 5 gallons of fuel in the tank) and knock almost completely disappeared. I got on Amazon and ordered a case of 12 bottles. Also, www.newegg.com shows a case of 12 for $9.95......if anyone is brave enough to see what they get and order it. It says case of 12 Lucas Octane Booster.
I also need to wire up the car for the trailer still.
Keep me posted on your progress!

[BadAssPerformance]

Went for a drive tonight to calibrate the speedo and see how it likes the 93 octane pisswater... heard a bearing noise in any gear over 40mph... trans is apart, rear intermediate shaft bearing cracked... hope that's it... found a new 4348270 (black seal) in the trans parts pile, so hope they are as good as the blue seal ones that came in them...

will post pictures later, the 3-4 bronze pads had some wear on them (only 3rd gear side) too, not sure if that's from bearing or what...

[Ondonti]

How much pressure did you have in your tires? One thing about our oem stuff is that with a 5 speed you can't get much for traction control in 1st and 2nd gears. People competitively racing 24.5" tires to save from breaking on 26's are trying to put down every bit of power they can. You are only 0.19 off your best 26" tire pass with an engine running poorly? I think that seems pretty good and I bet a little less power in 1st and 2nd might have you caught right up, plus if your engine was running well the 24.5's should perform better in 3rd and 4th gear. I don't know what 26's feel like but even with less power 24.5's were spinning for me in 2nd but it was not an out of control spin that slows you down. It was that lovely tire tearing sound

MY theory on the matter is that with high torque input there is obviously some relatively high spreading forces which put bearing load on the sleeve. With the helical set this also brings decently high axial forces which are flexing the bearing plate at the other end. So high bearing loads with axial movement repeated a whole bunch of times starts to walk the race off.

That was a long way of saying I agree that a stiffer bearing retainer would help the issue. My gut tells me it's the aluminum part flexing more than the steel part. Probably also worth a quick FEA study when I get a chance.

My idea was to brace the other side of the aluminum with a bored out spare retainer (to fit the gears past) that has braces and nuts welded to it so you can also put a bit more torque through the stackup or maybe even a larger fastener. The one concern I have is the point between the retainer plate and the outer endcase flange. That would require something that behaves more like the Moly plate upgrade for 555's. I think it would be fun to fab that kind of stuff up.

I think that sums it up nicely.

The question is if bearing support plate flexing is all of it or is the "float" of the rear bearing held in by a snap ring allowing the shaft to "float"? A tapered roller on both ends like the input shaft would be better...

The difficult side of things to take care of is the driver side bearing right? I would think fab and finding parts would be pretty easy for the passenger side bearing. I don't know about shimming it to line the gears up though.

[BadAssPerformance]

Yeah 24.5's are the path for now until some sort of whoopass trans revision or replacement is made

Wait till you see the latest carnage pics... cracked the aluminum plate not only to the input shaft bearing hole, but also cracked through to each of the 3 surrounding back-up plate bolt holes wondered why those bolts felt loose when taking them out!

Update... worked on car to 3am, trans is back together except the shifter housing on top. Would have had that done if I didn't realize I left reverse out just before I was ready to put sealer on the end cover and had to take it back apart

[168glhs1986]

I haven't read all your trans troubles and solutions but have you tried slipping the clutch? Someone told me Don Garlitts slipped the clutch. Much less of an on and off switch which seems to be the weak link to your setup. Heavy car, lots of power all at once. Go slow to go fast theory. Not an expert but just throwing it out there

[BadAssPerformance]

Good advice Mike! and I've been working on that.. never "dumped" a clutch in my life. The 26's made the 600hp clutch slip and the twin disk has almost no give... current plan is to learn to drive with the 24.5's... if I can make them hook, that *may* be gentle enough to save parts with the 26's

Was thinking a long clutch lever like top fuel would help?

[fishcleaner]

Was thinking a long clutch lever like top fuel would help?

I was heading that rout myself, an extension on the trans lever could made adjustable in or out to get the right feel. Ultimately I was thinking of a hydraulic dampener where you could just pop the clutch and thru adjusting the dampener get it just right.

[turboshad]

http://grannys.tripod.com/hillbillyclutchslipper.html

[BadAssPerformance]

I was heading that rout myself, an extension on the trans lever could made adjustable in or out to get the right feel. Ultimately I was thinking of a hydraulic dampener where you could just pop the clutch and thru adjusting the dampener get it just right.

I extended the clutch lever when I put the ACT twin disk in to limit the travel... still a small window. A hydraulic clutch with a restrictor should do it? T850 time?

http://grannys.tripod.com/hillbillyclutchslipper.html

LOL...

- - - Updated - - -

And the carnage...

[turboshad]

Now there's something I haven't seen yet. Good job JT.

A hydraulic clutch with a restrictor should do it?

Hmmmmmm, I wonder who's suggested something like that before?

[Reaper1]

Wow...that plate is flexing like a mofo! Time for a re-enforced plate, or a custom one...probably chromoly. It also illustrates just how much side loading is being made by the gearset under those conditions. Maybe a conical bearing, or some sort of thrust bearing is in order? (I know that's been suggested before...I'm simply agreeing)

[turboshad]

No need for moly as it would most likely turn into a deflection issue and not a yielding issue as soon as you went carbon steel. Mild without the pockets would probably do just fine.

[Reaper1]

I <3 overkill!!

[BadAssPerformance]

Now there's something I haven't seen yet. Good job JT.

Thanks! always fun to share new carnage, LOL, oie

Hmmmmmm, I wonder who's suggested something like that before?

Yep, the snowman from uranium land has some great ideas


Update: Yesterday took the "fresh" bearing trans'd Z down to Tuffy's for an alignment (Thanks CobraT93 & TurboRon25!) and it ran great, but STILL has the same bearing noise and after pulling the axles this morning I am thinking it may just be the OBX diff possibly beat to sh!t from the 5-6 axles that snapped off in it? ... hmm...

[85glht]

Update: but STILL has the same bearing noise and after pulling the axles this morning I am thinking it may just be the OBX diff possibly beat to sh!t from the 5-6 axles that snapped off in it? ... hmm...

It sucks that you went through the whole tranny only to have the same noise occur. Gonna just run it as is?