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

[Ondonti]

do you know the material needed and a place to get it?

seems like someone with a press/rivets could one off this stuff on a standard disc thats available.

Brian

One thing that I have noticed about carbon discs is a lot of material failures. That means you have to accept clutch rebuilds as a normal thing it seems. I don't know if vendors like that idea since we have some real complainers out there about "race parts," (like people wanting "soft" solid motor mounts). I am saying that based on the heavy use of RPS twin disc carbon clutches in 3000gt's.
I would think simply putting on new pucks should not cost too much as long as we avoid markup.
Maybe TU or FWD would be willing to try sourcing something. I would probably like to own 2 discs, one for use and one as backup in that situation. I honestly love my solid hub for driving but I think it kills parts. Carbonetic still seems to use sprung hubs which are not our friend at high rpms.

Hmmmmmm, all this axle breakage, should stay auto,

That power on pump gas from Brent, impressive.

Well 7.0:1 compression and more methanol then gasoline doesn't really count as pump gas haha. I still question the reliance on that much methanol because I don't truest the systems. Evos make 600 sometimes on 2/3 the displacement on true pump gas with smaller turbos!
I do think that JT on pure pump gas would save axles cause he would slow down. I also wonder how scared guys are to bog a little and save those axles. 2500 rpm launch control, etc. I am willing to bog a bit. I don't think its HP thats breaking anything for me, it was shockloading from a heavy rotating assembly at high rpms.
I have not made a pass on slicks in 3 years but I would like to start low and see how little RPM I could get away with and not completely destroy the 60' The problem with that is that as far as repeatability goes, you would need to use the same clutch technique each time etc. Heck, maybe low rpm launches with a lot of clutch slip could get near the same 60'. As long as your turbo is not too slow to come on.

I'm not sure what you are wanting me to do. You want me to FEA a splined shaft with similar dimensions to the stock pieces?:

Well if it was worth researching the stock size, why not the larger size. I don't know how much stronger that shaft would be but with how easy JT is breaking axles and my assumption that he is not actually going all out, a small increase in strength might just last a little longer, or still break on the first bad launch.

[Vigo]

I also wonder how scared guys are to bog a little and save those axles. 2500 rpm launch control, etc. I am willing to bog a bit. I don't think its HP thats breaking anything for me, it was shockloading from a heavy rotating assembly at high rpms.

Well i remember when ohiorob made a thread about 4t60s and i was trying to make the point that on the video of Stephane's old 8 sec Charger that it looked like he was leaving on ~5psi and clearly making up for it, that we wouldnt need to think about going to other trannies if people would just accept that they needed to launch a little softer. In that case it was more about brake-boosting autos causing a crazy spreading load between the ring and pinion in the autos, and in this case it is more about breaking axles with 5spds, but either way a softer launch is the answer. Seems like there are many ways to get a 'controlled' parts-saving launch that are not being explored in this community. There are people in this community who are making stock parts live through crazy stuff, purely with human finesse of working the clutch and shifter well, but anyone can have a bad day and break a lot of expensive stuff. I think once you get to a certain level you don't want to break stuff, and it would be nice to have a system in place to save your ---, and make your car more consistent so you can 'see around' some of the driving inconsistencies and find out what the variables you INTENTIONALLY change are actually doing.

[BadAssPerformance]

OK, took a little time to update the findings.... I re-measured and calculated the true axle angles (had not yet done this with coil overs and 26" tires) Measurement pictures attached,

calculations as follows:
Driv Side Pass Side
YZ (deg) 11 2.5
XY (deg) 5.23 3.83

YZ hypot L (in) 10.187 10.010
YZ - Z ht (in) 1.944 0.437

XY hypot L (in) 10.042 10.022
True Ang (deg) 10.96 2.49

The true angle is a little high on the driver side, but under the ~14° I had in my notes from a couple years ago. Also the axle angle reduces when the car launches.

I also looked at the tailshaft housing to see if it was supporting the passenger side axle sufficiently. I measured the current trans at 1.3995” and the old trans at 1.4005”. I measured the SET-1 passenger side axle at 1.3940” and the SET-2 passenger side axle at 1.3930” so on average about 0.0065” (diameter) or .00325” (radius) clearance. This sounds OK to me, thoughts? Measurement pics attached.


I then started thinking back to when the car started breaking axles. I just went from 24.5” to 26” tires and on top of that, I went to a twin disk clutch. I also was using a 2-step to launch with. I think this combination is what’s putting the extra stress on the driveline.

For SDAC, I decided to air up the 26” slicks and launched without the 2-step and slipped the clutch. On SET-1, (Muncie Dragway), I made 5 passes between Q8 qualifying and was the Q8 runner up. Was very excited that they were holding up well! SET-1 was one of the sets that was tempered at a lower hardness to try to improve the “spring” and be less brittle. On to Monster Mopar Indy (Lucas) I made two good time runs on Friday. After all of these clean launches, I was thinking the 2-step was the main problem? We were rained out Saturday and on Sunday morning for the time run, the axle broke right at the line, BUT this was a new failure, the outer CV joint on the driver’s side instead of the splined inner end. I have not taken it apart, so not sure if it is the joint or the shaft? It does look like the splines on the inner end of the driver side shaft are starting to twist. I attached pictures and uploaded a video: Driver Side Axle (Set 1)
http://www.youtube.com/watch?v=m1mJK1wZ8-c


I swapped in the SET-2 before round 1. I really appreciate DSS shipping these to the hotel during the events and was very glad to have them. I forgot to confirm if these were the “standard” heat treat, or if they also had the better temper? I’m guessing these were standard because even slipping the clutch, launching in round 1 the inner end on the passenger side axle broke like the others. It also appears that there is some play in the inner CV joint. Could this be a potential cause of fracture? Upon further inspection it also appears that the driver side inner splines started to twist as well. I attached pictures and uploaded a video: Passenger Side Axle (Set 2)
http://www.youtube.com/watch?v=rWTpDscUJ9A


I think that the new temper helped. I also think that a softer launch without using the 2-step also helped.

I sent a very similar e-mail to DSS and the axles will be back on the way to them tomorrow. I am also looking to get the axle stub ends hardness' measured.

I really want to figure this out, but am currently thinking about going back to 24.5” tires or a lighter single disk clutch or both just to try to improve longevity...

[turboshad]

When I get a chance I'll try to do a more thorough analysis with splines and also see how much the 6-7 thou play contributes. I took a look at the axles I pulled from the Shadow last fall and there are no signs of twist. I've had this set in since I broke my only axle while I was in the 11s. After that break I changed my launch technique to be a bit softer and haven't broken one since. That being said you have waaaaay more passes under your belt and on your axles then I do. I'll be curious to see what happens when I go 26s with a twin like yourself, though I do plan on incorporating some launch slip control with the hydro setup. I think I've got it figured out to be able to program in a time or speed based slip curve so I can completely tune the whole clutch release. I'm excited though it will still be at least a year before I have things back together.

[Aries_Turbo]

...... though I do plan on incorporating some launch slip control with the hydro setup. I think I've got it figured out to be able to program in a time or speed based slip curve so I can completely tune the whole clutch release. I'm excited though it will still be at least a year before I have things back together.

MCU controlling a hydraulic solenoid with PWM? a setup like that with feedback to increase or decrease the slip time as needed would be killer.

Brian

[Ondonti]

MCU controlling a hydraulic solenoid with PWM? a setup like that with feedback to increase or decrease the slip time as needed would be killer.

Brian

Well it might also be a money maker.

26 vs 24.5 was a huge deal with FWD import racing was still big. The 26's were basically banned from the non outlaw SFWD races (and even some of the outlaw races) because the use of 26's meant people with small budgets couldn't really participate. Most people here probably did not follow much of their struggles. I also don't think those people were very open about some of their problems. A large number of people who were unable to participate in events were those who broke axles at the last event and were waiting for replacements, or were borrowing the other guys axles when another car was down, etc. Bigger money teams had multiple sets of axles. They had multiple companies competing for business at the time and still had little success. The faster cars that are more consistent are guys who are being very very careful even if they have high dollar parts. Nobody wants to have to fix their car between rounds (or get knocked out) instead of spend time dialing it in.
I will also say to those looking for invincible parts without regard to using safeguards, even the high dollar teams took apart their Liberty dog boxes every race and regularly found parts failing, especially on 26's

JT, did you do any measuresments FWD to AFT for those axles? I know we can reclock the transmission up and down with the bobble but that changes the FWD/AFT angles.

[BadAssPerformance]

When I get a chance I'll try to do a more thorough analysis with splines and also see how much the 6-7 thou play contributes. I took a look at the axles I pulled from the Shadow last fall and there are no signs of twist. I've had this set in since I broke my only axle while I was in the 11s. After that break I changed my launch technique to be a bit softer and haven't broken one since. That being said you have waaaaay more passes under your belt and on your axles then I do. I'll be curious to see what happens when I go 26s with a twin like yourself, though I do plan on incorporating some launch slip control with the hydro setup. I think I've got it figured out to be able to program in a time or speed based slip curve so I can completely tune the whole clutch release. I'm excited though it will still be at least a year before I have things back together.

An analysis if the play hurts would be great!

For passes on DSS axles...

24.5" slicks, ~200 passes, no axle break
26" slicks, most I have gotten on a set is ~10

Well it might also be a money maker.

26 vs 24.5 was a huge deal with FWD import racing was still big. The 26's were basically banned from the non outlaw SFWD races (and even some of the outlaw races) because the use of 26's meant people with small budgets couldn't really participate. Most people here probably did not follow much of their struggles. I also don't think those people were very open about some of their problems. A large number of people who were unable to participate in events were those who broke axles at the last event and were waiting for replacements, or were borrowing the other guys axles when another car was down, etc. Bigger money teams had multiple sets of axles. They had multiple companies competing for business at the time and still had little success. The faster cars that are more consistent are guys who are being very very careful even if they have high dollar parts. Nobody wants to have to fix their car between rounds (or get knocked out) instead of spend time dialing it in.
I will also say to those looking for invincible parts without regard to using safeguards, even the high dollar teams took apart their Liberty dog boxes every race and regularly found parts failing, especially on 26's

JT, did you do any measuresments FWD to AFT for those axles? I know we can reclock the transmission up and down with the bobble but that changes the FWD/AFT angles.

Yeah, the 26's seem to be a major culprit here...

I originally mounted the 2.4L with the axle centerline within 3/16" of stock, but I have custom solid mounts on all sides so can move the axle centerline a bit, at the cost of having to re-route intercooler plumbing

[turboshad]

Did you ever find out if they are through hardening or case hardening? If case, will they tell you the hardness and case depth?

[fishcleaner]

Yeah, the 26's seem to be a major culprit here...

You would think the more sidewall on the 26 would offer more stress relief or was the 24.5 spinning and the 26 hooking up?

[Reaper1]

It looks like the axles are case hardened.

Axle alignment is very important.

I wonder if you can leave the 26's, 2-step, ect, but use the engine tune to do torque management while launching?

[Vigo]

You would think the more sidewall on the 26 would offer more stress relief or was the 24.5 spinning and the 26 hooking up?

Well, i think the main thing is preventing load 'spikes', and to my thinking, if the 26s are easier to wrinkle and harder to spin, they are probably worse about that spike than a smaller slick. Imagine it like running a bumper car into a spring mounted to a wall. A stiffer spring attached to a wall that will move, is a lot better than running into a soft spring attached to a wall that will NOT move.

[contraption22]

I know many consider it cheating, but if you add a small shot of nitrous, you won't have to launch as violently and you will be able to save some axles.

[turbo2point2]

Eric sent me these pics to share. I have a few more I can load later on...

[Reaper1]

So he cut off the stock end and welded on....????

[bakes]

but the majority of the brakes are at the splines

[BadAssPerformance]

Did you ever find out if they are through hardening or case hardening? If case, will they tell you the hardness and case depth?

Will try to find out, or measure the pile of snapped off ends... you got a rockwell or knoop tester there?

You would think the more sidewall on the 26 would offer more stress relief or was the 24.5 spinning and the 26 hooking up?

Yes stress relief until it grabs which is only 30° or les sfo tire rotation? I think the combination of hook (instead of spin) and the 13" moment arm (vs. 12.25") combine for a harder hit

I wonder if you can leave the 26's, 2-step, ect, but use the engine tune to do torque management while launching?

Yeah, I could stage boost or bog it with fuel or timing... hard part is tuning to different tracks this way

I know many consider it cheating, but if you add a small shot of nitrous, you won't have to launch as violently and you will be able to save some axles.

I've thought about it, but really i havn't even turned up the boostor even adjusted teh cams or anything to make more power yet. Just been trying to 60' the car better to get the ET more in line with the MPH

Eric sent me these pics to share. I have a few more I can load later on...

Thanks Brian adn Eric! Possibly got any zoomed out to show the whole axles? or one of the inner end of the long axle where I've been breaking?

[Ondonti]

BTW, even Red Sled was been running 24.5's at almost everything he has been doing.

BTW, if you have the ability to retard timing per MPH (or time based retard) then you can run tons of boost but make very little power. This way you can keep the turbo spooled up but your hit will have less power behind it (and ramp up as quickly as you want to bring timing back since the turbo is already spooled up).

I think setting the car up to bog and then fighting that with clutch slip would be the simplest way. Either you have bog pass or you slip the car through to a great pass ......instead of your "bad" pass being a breakage because you were too harsh with the clutch.
I think that is what I will try as long as I am with my current drivetrain. Low 2 step and try to clutch slip out of it. I don't believe in the blip throttle thing as long as you are trying to be consistent. Consistent launches are something you can slowly improve as you tweak things and that should prevent you from breaking things...and if you are consistent you should be able to tell what mistake lead to shockloads and breakage.

T-850 requires a bunch of upgrade parts and I don't know what happened to the high dollar Ragetek dogbox. They did sell a billet input shaft since the OEM one is garbage. The website has all that stuff removed now, and the cost was 1500 bucks for just the input shaft, 5200 for the dogbox builder kit with untested parts.
Interesting thread here where Red Sled thought about but never ran the dogbox but mentions billet straight cut transfer gears for the 31te that Frenchy Ran and he was trying to make some.
http://www.srtforums.com/forums/f56/...06/index3.html

[contraption22]

I've thought about it, but really i havn't even turned up the boostor even adjusted teh cams or anything to make more power yet. Just been trying to 60' the car better to get the ET more in line with the MPH

Sounds like you are arguing a pretty good case to spray!

[BadAssPerformance]

$1500 input shaft? .... oie.

Ordered a set of 24.5" M&H's... Thinking to be safe I might go back to a single disc clutch too? Hmm....

[Reaper1]

$1500 for a custom input shaft isn't bad, if it's made correctly. It's a low volume part made of a material that is a serious pain to machine, and requires some machining methods that take the correct tooling to make happen in the tolerances required. Plus, you guys are already spending that much on axle sets. At the point in the game that you guys are at, I don't think it should surprise you at all that this kind of investment is what is "normal" to get some semblance of reliability out of 25+ year old technology that is being pushed to 400%+ of its nominal load rating.

Yeah, we love our TM's. We love how "inexpensive" it is to get to a certain level of performance. However, I think it's quite acceptable to expect this kind of investment to get the best of both performance and reliability at this stage in the game. Look at what the diesel guys spend on transmissions. They don't blink at spending $3k on a torque converter, $800 on an output shaft...ect. Looking at the performance gains on a percentage level, and we aren't that much different.