Awesome. A new noise!

XR4Ti / Sierra / Sierra Cosworth Discussions - Questions, problem resolution, general talk, technical tips and modifications.
my8950
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Re: Awesome. A new noise!

Post by my8950 » Fri Nov 29, 2019 1:42 pm

I haven't heard many positive things about the Autozone or other cheapie rebuild axles based on research I've done here. You can rebuild the CV's yourself if you have much skill, sounds like you'd be fine based on the other things you've said that you've done to the car. Can get the boots from rock or other vendors pretty cheap, a VW part fits on ours nicely.

Is this the Ford Motorsport aluminum driveshaft you have?

thesameguy
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Re: Awesome. A new noise!

Post by thesameguy » Fri Nov 29, 2019 2:51 pm

100% agree in Surtrack... I've read mixed reviews but nothing overwhelmingly positive. I can replace the bearings - they're already torn down - but at least one cup is probably not reusable so that's a roadblock.

I will keep the old hardware in case of emergency (or I find some cores!) , but right this second I don't see a way to get the car going again with only a rebuild.

The driveshaft is the FMS aluminum. It should be able to put up with a lot of punishment so I'm confused as to its issue. I may have overlooked something, but I will yank it and have a pro check it... it's a good use of $50.

I'm not sure how to make up the 11/16" of the layer transmission. Is a Haulsee adapter still useful if it's only 5/16" thick? ;)

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Re: Awesome. A new noise!

Post by thesameguy » Mon Dec 02, 2019 11:44 pm

Got the first of two drive shafts in... it's... interesting.

I'm not sure what this finish is, but it's fun!

Image

The bearing looks fine, and it's certainly less clunky than what's on the car, which is a plus.

Image

They have found some fun ways to cut cost, including eliminating clamps for the boot... it appears they are just glued in place! Also, the cup itself is demonstrably less substantial than the factory cup.

Image

I've seen worse in terms of aftermarket drivetrain parts. I think I am going to put some ear clamps on the boot just in case, but otherwise I don't see a reason not to install this one.

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Re: Awesome. A new noise!

Post by thesameguy » Tue Dec 03, 2019 6:16 pm

While preparing to remove the DS I did some more poking around, and I think the reason I am getting wobble in the DS is because the rear flange is not quite centered on the Haulsee adapter. Whether it's always been that way or it just shifted I don't know, but I'm pretty sure that's where the wobble is from.That cannot be good for the diff, so now I'm worried it's the source of the racket.

Bah... I feel like this is becoming a whole reinvention thing! Really wish I had a spare auto diff on hand, too. I guess I need to fire up a gear ratio calculator and compare 4cyl T5 + auto diff with late 6cyl T5 + manual diff. Maybe the net result isn't that bad. I do have a spare manual diff.

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Re: Awesome. A new noise!

Post by thesameguy » Tue Dec 03, 2019 8:02 pm

Just aggregating stuff here for when I get frustrated and just start spending money.

This thread:

http://forums.merkurclub.net/forum/view ... hp?t=32552

talks about this part:

https://www.powertrainindustries.com/st ... ange_yokes

with a ~13/16" spacer means the FMS DS can bolt directly to the diff without the Haulsee adapter. I don't know whether the FMS DS uses 1310 joints or 1330, but I'm pretty sure there are 1310 to 1330 joints to solve that issue. Then the MD-401-2110 takes up the remaining 11/16" lost.

my8950
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Re: Awesome. A new noise!

Post by my8950 » Tue Dec 03, 2019 9:28 pm

Doesn't look cheap...Id say if you already have the D/S and adapter, throw it back together and then measure the runout on the spacer to see if its off. If so, try and center it up.

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Re: Awesome. A new noise!

Post by thesameguy » Tue Dec 03, 2019 11:00 pm

Yeah, not cheap but honestly I'm less concerned with relatively small money and more concerned with it working exactly right the first time. A longer front slip yoke and that PTI flange with a V6 transmission (relocate the shifter) would be an exactly right solution for not huge dollars. That's very attractive to me.

I pulled the DS out tonight and I don't have a good explanation as to the problem. There is a lip on the adapter so the DS has to be centered. The runout on the side of the adapter is fine, so both it and the diff flange are good. That leaves either damage on the driveshaft-side yoke or the face of the adapter isn't square and both of those seem unlikely. IDK... this has nothing to do with the problem I am actually trying to solve, but now I gotta solve it too. DS and adapter are going to a shop.... we will see what they say.

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Re: Awesome. A new noise!

Post by john keefe » Fri Dec 06, 2019 4:35 am

Just a thought (might have mentioned this earlier in the thread): one-piece DS works fine with floating rear axles, as you can tip the diff to equal the angle of the DS coming off the transmission. Cancels out a lot of NVH on smooth surfaces, and the u-joints wear mostly the same. I don't know all the reasons FMS dropped the one-piece DS from their rally cars, but IIRC one was because they couldn't legally (FIA) change the engine/trans mounting heights enough from stock to deal with all that brutal hi-RPM boost/torque on the front u-joints and NVH.

I don't know about slotting mounting holes to pivot the fixed diff, but if your DS et al check out OK, maybe try playing around with the T5 tail height so that the "smooth road" angle of the DS off the tail housing is as close as possible to the DS angle coming off the diff. I don't know if that means raising of lowering the tail angle. But, you could shim the trans mount up, or the trans cross-member down from the chassis, then do the laser pen runout check until you get a near perfect circle. The downside would be you'd probably want to go to PU or at least slightly harder durometer engine and transmission mount bushings to maintain alignment. More NVH from transfers through the mounting points, but better than annoying vibrations aft.

Speaking of NVH and mounts, since the turbo downpipe is essentially bolted solid to the turbo, maybe that's a contributing factor to the noise? If it is really is a solid connection at the turbo housing, then its relying on flexing in the couplings/clamps and solid exhaust piping and hangers after the downpipe. Not very clever.

How close is the exhaust to the DS? All the hangers in great shape? If the motor mounts are weak, torquing under load (and releasing from load) moves the exhaust around a lot, and that might be one of the culprits. On the XR's 2.3's I've had, I basically did the old drag racer's trick of strapping one side down at the mount to prevent movement, and went with either TBird SC bushings, or PU bushings. If I ever had another, I'd also seriously consider sectioning the downpipe, and welding/clamping on a SS flex pipe, as Volvo and a few others typically do/did for their turbo engines back then, and I assume most everybody does these days. Or putting it in the exhaust pipe immediately aft of the downpipe clamp, then strengthening the hanger mounts aft.

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Re: Awesome. A new noise!

Post by thesameguy » Fri Dec 06, 2019 12:46 pm

I don't have much in the way of NVH from the driveshaft - at least nothing I would attribute to an angle mismatch. The car isn't BMW smooth, but it's very tough to divorce the NVH from a big four cylinder coupled with race springs and high-PSI Z-rated tires. LOL I don't feel anything I would describe as problematic at the shifter, for example. I'm 100% certain I could fix some NVH with a two-piece driveshaft, but it wouldn't turn the car into BMW so I haven't really pursued it. :) I DEFINITELY need to do a laser runout check, though... I've been running on "it feels about right" for a decade. :)

The exhaust has pretty good clearance. It's a stock downpipe but a 3" cat and 3" Stinger system modified to exit out the wrong side in back. It's been there longer than the transmission, and I don't have a reason to suspect it. I am planning on doing a 3" downpipe with a flex section before the cat as I think it's good practice, although I'm not sure how truly important on a longitudinal engine. But, it wouldn't make things worse! Unfortunately things like "crazy noise" always pop up and my budget for exhaust mods go elsewhere!

It's been pouring rain and I haven't gotten the DS out to take to the shop, but hopefully that can happen over the weekend. I may go ahead and remove the transmission as well. I've been wondering if the TOB is wearing the bearing retainer and that's why the noise is affected by clutch position. Since I can only hear it at very low speed, all my testing is in 1st gear so I cannot account for any differences that might be present in other gears.

john keefe
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Re: Awesome. A new noise!

Post by john keefe » Fri Dec 06, 2019 2:07 pm

Yeah... all the hi-po suspension upgrades make for a go-kart ride, but a little harsh for normal driving. Lot of mysterious noises and mini-jolts of which you're never sure are an issue, or just feedback from the lack of NVH isolator. I'm thinking of getting rid of the compression strut front and rose-joints to go back to a Cossie front sway bar setup w/ PU bushings. The C-strut setup is precise, and lively, and no doubt it would be perfect on a smooth track, but after a while its just too much to enjoy the car elsewhere.

Seems like you're missing the same essential troubleshooting tool as me: another good driver so I can sit in all the other seats for as long as it takes to ID exactly where noises seem to be coming from.

If you're going to swap out the TOB, install a steel-sleeved bearing retainer if you don't already have one. I don't recall if there's a version specific to the 2.3L/T5 combo needed, or if you'd have to machine a 5.0L steel one shorter. Should be just a simple swap.

thesameguy
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Re: Awesome. A new noise!

Post by thesameguy » Fri Dec 06, 2019 2:32 pm

I think there is no steel option for four cylinder T5s. The input bearing is physically larger on the 4cyl transmission, so the "regular" steel retainers don't fit and nobody makes a "4cyl only" version.

I think this is one of the things I can solve by switching to a '94-'98 V6 transmission - a steel bearing retainer should be bolt-on. IIRC V6/V8 transmissions are more or less the same, minus torque handling. I wish there was a quick way to get the long input shaft of that V6 transmission on the "Z-spec" V8 gearbox. Blech.

I wish there was a W154 to 2.3 bell housing. I would consider that option!

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Re: Awesome. A new noise!

Post by john keefe » Fri Dec 06, 2019 6:53 pm

Worth spending the money to have a machine shop turn the 2.3L AL shaft down to allow a steel tube w/ the correct outside diameter for the 2.3L TOB?

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Re: Awesome. A new noise!

Post by thesameguy » Fri Dec 06, 2019 7:23 pm

Maybe, but in general I like the idea of just switching to the later V6 transmission - it's more available than 2.3l T5s are, moves the shifter to a better place, and gives me access to the steel retainer. That's all win. The only problem is creates is that I either need to shorten a 1.5" Haulsee adapter by 11/16" - which I think isn't possible - or I need to come up with an alternative to the Haulsee adapter. My thought is to use that PTI yoke so I can bolt the FMS driveshaft directly to the diff, and then use an aftermarket, longer T5 slip yoke to make up that 13/16". That's $$$ in hardware ($150 Modern Driveline MD-401-2110, $150 PTI 3102-1409, $x slip yoke) BUT none of those are wear points, so it's a reasonable long term investment in my mind.

Really the thing holding me back is gear ratios. The standard 2.3 T5 has a short 1st and an ugly 2-3 shift, but I like 3/4/5 with my auto diff and that's where I spend most of my time.

Pretty sure my transmission is from an '86 TurboCoupe:

Ratio = speed@6000rpm w/ 215/45-17 tires:

3.36 diff & '85/'86 trans:
4.03 = 32.45
2.37 = 55.18
1.49 = 87.77
1 = 130.78
.81 = 161.46

3.36 diff & '94+ V6 trans:
3.35 = 39.04
1.93 = 67.76
1.29 = 101.38
1 = 130.78
.73 = 179.16

3.64 diff & '94+ V6 trans
3.35 = 36.04
1.93 = 62.55
1.29 = 93.58
1 = 120.72
.73 = 165.37

Seems like the tall auto diff with that V6 trans might be too tall... I think the car could turn them ok, but it'd probably feel slow. Switching to a manual rear end reels that back in quite a bit. I have a spare manual diff in the garage I can use, but of course if it's going in to fix this issue, it's obviously gotta get an Eaton LSD in there, right? MISSION CREEP.

john keefe
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Re: Awesome. A new noise!

Post by john keefe » Sat Dec 07, 2019 3:23 pm

I think it all depends on where you're making your best torque.

Been so long, I forget if my T5 has the V8 3.15 or the 2.76 1st gearing (probably the former). I have the 3.64 diff, and I don't wind it out in 1st. Like driving a semi-truck. Seems like I'm always shifting out way early to get to the much more pleasant (and practical acceleration when you need it) 2nd gear. You can hit 25mph damn quick, but why risk blowing up the rear end? If I let other people drive it, I always have to remind them, "It ain't for drag racing, so be very gentle in 1st." Still, you get a lot of wannabe's launching next to you, and you just have to putter along until you shift to 2, then reel them in pretty easily. :D

I don't know how your 2.3L is built, but if I was building it all over again, I'd consider "comfort" in 1st a lot more.

Here's a great site for reference on car specs and comparing combos: https://www.automobile-catalog.com/

For mine, its more a problem of an overall too-short combo. Just for "stock" comparisons, the XR weighs about 240lbs. less than the same year Mustang 5.0L, and the stock 5.0L has 300 ft-lbs of torque before 3200rpm, vs. 2.3L @ 200 ft-lbs around 3000rpm. Diff drive ratio for the 5.0L was 2.73 stock, "optional" hi-po ratio @ 3.08. So, 3.64 is way too short for my XR combo with any of the WC V8 T5's, unless you find one of the rare 2.70 1st aftermarket ones. A LOT of GM T5's in that period came with 2.70 1st's. Around here ANY T5 is tough to find because all the kids kept blowing them up in the 90's.

I have a good auto 3.36 sitting around, and I sometimes think about swapping out the ring and pinion, but my diff is an FMS LSD, and I don't want to temp fate trying to put it back together with all the correct tolerances. If I had the time and $$$, maybe do an Eaton on the 3.36, but then I've got to find the larger stub shafts.

For reference on combos... The Mustang SVO, surprisingly weighed only about 20lbs less than the 5.0L (5.0L = 3159lbs, or 220lbs more than an XR), but had a 3.39 1st, and a "special" final drive ratio of 3.73. I'm guessing that was what they found to be the best all around driving ratio for the weight and torque curve of the intercooled 2.3L. You'd think that that diff ratio would have improved the SVO's acceleration on road course compared to the 5.0Ls, but one of the track criticisms was that it didn't have the low-end grunt of the 5.0Ls, so was always at a disadvantage coming out of turns. Then when you did hit the turbo's power band, that 3.73 pulled you past it too quick (area under power band curve too narrow).

Curiously, the TBird Turbo Coupe weighed the same as the 5.0L (3161lbs), but had a ratio of 4.03/3.45. Which puts you roughly the same if you combined it with a 3.36. But, I don't know why they went with the 4.03 if you weren't moving significantly more mass than a GT, or SVO???

Granted, the Mustangs and TBird had solid rear axles, so you didn't have to worry about blowing anything up in the rear.

The 3-Door RS Cosworths weighed 2727 lbs. (425lbs. less than a 5.0L, 205lbs. less than an XR), had the 3.64 rear, and a 2.95 1st.

Don't know if that all helps, but its a little more prep info...

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Re: Awesome. A new noise!

Post by thesameguy » Sun Dec 08, 2019 12:01 am

I've got a pretty well built engine... running a stock LA3 computer, but more or less everything that should be done has been done - engine, suspension, brakes, all of it. I've replaced heavy bits with light bits where I can (eg, light wheels, light driveshaft, light brakes) and eliminated things I don't need (like spare tire, air conditioning). With more power and less weight (although the big RS500 intercooler added some back...) the thing is quite fast. Turbo is a ball bearing hybrid T3/T4 and very responsive - 2600rpm on the freeway in 5th does not require a downshift to get moving. But, 1st and 2nd are much too short (although I do get good boost in 2nd) and very annoying, so they could stand to be taller. Switching to the manual diff and the V6 transmission would be a slight increase in overall ratios... keeping the auto diff I *think* would be too tall. The other upside of switch to the manual diff is it's already off the car, so I have the opportunity to stick in an Eaton LSD.... :)

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