Better to break axles than the tranny. It's a pain, but you'll save time and money in the long run.
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Better to break axles than the tranny. It's a pain, but you'll save time and money in the long run.
By the way, Axles do bend before they break.
twisted shafts.jpg
If you have any worries, you can put some lines on them so you can eye out for pending failure.
Bob
Last edited by Bob_n_Cincy; 10-09-2015 at 10:17 AM.
818S #22 Candy Blue Frame, Front Gas Tank, 2.5L Turbo, Rear radiator, Shortened Transmission, Wookiee Compatible, Console mounted MR2 Shifter, Custom ECU panel, AWIC soon
My Son Michael's Turbo ICE Build X22 http://thefactoryfiveforum.com/showt...rts-818S-Build
My Electric Supercar Build X21 (on hold until winter) http://thefactoryfiveforum.com/showt...e-Build-Thread
I *heart* Bob_n_Cincy.
Great idea! For a heavily tracked R-car this should be standard practice. Is there any rule of thumb for how much they'll twist before giving up or are we just going to have to set baseline data for it?
Best,
-j
818S #22 Candy Blue Frame, Front Gas Tank, 2.5L Turbo, Rear radiator, Shortened Transmission, Wookiee Compatible, Console mounted MR2 Shifter, Custom ECU panel, AWIC soon
My Son Michael's Turbo ICE Build X22 http://thefactoryfiveforum.com/showt...rts-818S-Build
My Electric Supercar Build X21 (on hold until winter) http://thefactoryfiveforum.com/showt...e-Build-Thread
They put HP ratings on many of the products on their site. I'm guessing that what Frank is referring to is a reluctance to give a rating on a custom job. As Bob pointed out, torque seems more relevant than HP.
Frank - are you saying that they wouldn't give you a HP or Torque rating, or did they only avoid answering the torque question?
Torque is the only relevant factor.
Wayne Presley www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos
Haha. Yes, torque is all that matters. They put horsepower because that is typically what the general public knows. What the general public doesn't know is that hp is derived from torque and rpm. Without a known torque value, you couldn't calculate hp. So to Wayne's point, torque is the only technically meaningful value.
Even better would be torque at the axle instead of wheels since every car has different gearing.
Yes, "torque at the axle" is what matters. Which is a function of crankshaft torque and gear ratio. The momentary torque the axle sees will by much higher during a hard launch than the calculated value of crank torque times gear ratio. How much higher depends on how much the clutch slips and and how much grip the tires have.
To me HP means nothing. Because HP is derived from torque, torque is the true measure. I said HP on my post (I think?) cuz many people use that figure (even DSS).
They never gave me a number they would stick hard on. I don't blame them, there must be a good reason. All I know is they (my shafts) will handle over 400wtq, probably 500+, but the way they answered to me meant that even with 400 they could break, they never said "if they break we refund you". They used words like "strong", "not very strong", "stronger", "strongest I got", "a lot stronger", etc... relative words.
Actually I re-read my emails... The guy said "I guess our axles would handle 450hp". Those are the chromoly axles, hardest one they have for the Subaru diameter. That is with the stock Subaru 24 splines, which are the weakest point. I have asked them to bore me the hubs for stronger splines and he said "this would make our axles a lot stronger". But no number... To me it means over 500hp or over 500tq, probably similar.
I will ask them again by saying in writing that even if I have 200wtq and they break, I won't sue them. Maybe they will give me some kind of number. I just want a ballpark, if he says they handle 700+ or not more 400, that's a huge difference, I'm sure they have an idea. They have a lot of customers breaking their Subaru parts (axles, CVs, splines).
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
I wouldn't expect any number to be terribly precise. Everyone should be aware that once you take them out of a lab and put them in the field, there are too many variables to trust the number with much certainty. Considering that they have ratings on a lot (or all?) of the axles on their website, they must have some way of establishing a ballpark. I doubt they've faced any lawsuits from someone that broke one of their axles. If that ever happened, you'd probably find a bunch of disclaimers on their site.
Like I promised 9 days ago. "I will keep you informed"
Michael and I had a great weekend auto crossing. Between us we had 27.001 runs.
Everything was running perfect until our very last run opportunity.
So Michael was on the edge of making a 60 second lap all day. So his launch might have been a little extra.
Here are the results.
https://youtu.be/HS9kN_Pd_78
Last edited by Bob_n_Cincy; 10-11-2015 at 08:45 PM.
818S #22 Candy Blue Frame, Front Gas Tank, 2.5L Turbo, Rear radiator, Shortened Transmission, Wookiee Compatible, Console mounted MR2 Shifter, Custom ECU panel, AWIC soon
My Son Michael's Turbo ICE Build X22 http://thefactoryfiveforum.com/showt...rts-818S-Build
My Electric Supercar Build X21 (on hold until winter) http://thefactoryfiveforum.com/showt...e-Build-Thread
Doh! Another failure.
Talked with DSS again. The custom Axles are good for 3000 foot lbs of torque which is about 450 at the flywheel. As Frank mentioned above, the weak point is the small diameter on the outer end. DSS makes larger diameter Axles that come with custom hubs which will be good for 850 foot pounds of torque at the flywheel. Waiting to hear back from them on cost but I would imagine $1900 for those. Not needed for most of us, but it's an available option.
Pretty sure they rate them at HP because that's what people know and usually torque is within 15% of peak HP so it's close enough.
Last edited by Hindsight; 10-11-2015 at 09:09 PM.
$USD1,300.
I know this isn't my thread, but it's about options for broken axles, so I guess it's relevant.
Here's my breakdown:
- DSS bigger/stronger WRX outer CVs: $500 (pair);
- DSS chromoly as-strong-as-possible-for-that-diameter bars: $400 (pair);
- Porsche G50 108mm inners: $200 (pair);
- Broaching Subaru hubs to fit the bigger outers: $200 (pair).
Now I got numbers. They have seen these bars and outers CVs on much heavier cars with 700whp+ and some work no problem, some failed. All parts can fail, there is no weak point a lot weaker than the other parts. Depends of all the variables, driving style, tires, weight, road condition, etc. They think with such light car (950-1000kg) there should be no problem to handle well enough 700+. Weight is helping here.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
I'd be in for the $500 shaft upgrades.
Zero Decibel Motorsports
Check out my new website!
www.zerodecibelmotorsports.com
www.facebook.com/zero.decibel.motorsports
Adam _____ Instagram @PopesProjects____ YouTube Channel
818 SRX - #91
Arrived 01/02/2014
First Start 10/31/2016
First Drive 05/22/2017
Registered 10/25/2019 BRAP818
You know the saying... speeds costs money, how fast do you want to go?
I don't think I've seen anyone break the transmission with a stock engine setup. I think all the failures have been with higher than stock outputs. I THINK the same is true on the axles but am not 100% sure of that.
The bottom line is that there are a lot of weak points in the system when you go much above the stock HP rating. Known weaknesses are:
- Pistons
- Clutch
- Axles
- Transmission
- Intake charge cooling
If you want to keep costs low, just stick with the factory output. If you want to go faster, it's going to cost a lot more. It's not like working on a muscle car or a Toyota that was engineered for nearly double the stock output (though don't get me wrong, I wish it were).
Another weekend, another failure.
We're looking into it but it would appear to be an alignment issue. I neglected to mention minimum track width when I had the car aligned and my guess is they're binding and snapping off from lack of plunge. The settings are all we have changed since the car was built and there's no reason they should be failing at this rate all of a sudden due to power. Going to have a pair built regardless.
EDIT: Not track width. We're 3/4" over min per side. Also this failure was a shattering of the OEM outer, I predicted this before the car was ordered, that part of the CV was never made to handle a fraction of thee power these cars can make (even stock)
Time to call DSS I suppose.
3sF39qG.jpg
Last edited by SixStar; 10-13-2015 at 02:33 PM.
Owner/builder - AEM Intakes 818R #85
Adam _____ Instagram @PopesProjects____ YouTube Channel
818 SRX - #91
Arrived 01/02/2014
First Start 10/31/2016
First Drive 05/22/2017
Registered 10/25/2019 BRAP818
I would not trust the 5 speed much over 250whp. Keep in mind that is well over stock HP which is 227 or something, at the crank. 6 speed would hold up to whatever you throw at it. 5 speed would need the PPG gears. Cheaper to go 6 speed but heavier and is a lot of gears for a light car.
Again, Limited, but lots of track time since December of last year (283HP/304TQ) to rear wheels. ~2270 weight with me. No launches, but I abuse the crap out of it otherwise with Hoosiers R7's- with crazy fast laps (for 20 min each session lol). Still on original used transmission (78k miles), and original CV's- No issues. Pick your poison I guess.
Thanks- Chad
818R-SOLD!!!- Go Karted 7/20/14/ Officially raced NASA ST2- 2/28/15
2016 Elan NP01 Prototype Racecar Chassis #20
1969 Porsche 911ST Vintage Race Car
1972 Porsche 911T (#'s matching undergoing nut & bolt resto in my garage)
higher than stock HP and TQ and shock loading is def the issue and remember in stock config the power is divided front and back vs just back. I would assume that the outer CVs might be a weak link... what is dist front to back with a stock Subaru?
We see axles, CVs and trans issues at autocross but they always grenade when those cars leap off the line due to such great grip. An 818 will always be limited by tires...
Dan
818S #17 Picked up 8/1/13 First start 11/1/13 Go Kart 3/28/14
That looks like an issue with the metal, I would magnaflux the next set regardless....in know we will be!
We have several 5MTs in the 12s with no issue. Fluids and the loose nut behind the wheel go a long long way. Saying that all 5 speeds will grenade at X power is a bit of an overgeneralization. I've broken 5MTs on stock WRXs, I destroyed an RA box with a massive 265wtq, I've destroyed an RS transmission with 105wtq. Previous life and current abuse factor in heavily. In the end they're all just parts and results may (and do) vary.
Owner/builder - AEM Intakes 818R #85
Are the 5MTs in the 12's running front wheel drive only?
I disagree. The 5 speed has a reputation for being weak but that is not what I have experienced. And there are differences between the older 5 speeds based on model of car and year. For sure old 2002 WRX 5 speeds are not as strong as newer ones. I think they made the change to thicker/stronger gears in 2008. The 2005 + Legacy trannys are stronger than old WRX trannys. I'll do some research and put together a chart with what years and models have the different gear strengths, I know I've seen it all posted on NASIOC and Legacy GT forums.
Anyway in my case my Legacy GT 5 speed survived 2 seasons of professional endurance racing on the Factory Subaru Road Race Team in the Grand Am Cup, a season of Tarzan Yamada driving it in Time Attack, then a year of my amateur shifting in the ICSCC conference racing. And that's in a 3300 lb race car. It's still fine and I will probably use it in my future 818R. Possibly one of the reasons it lasted is the SRRT installed a tranny cooler and pump after the first test session (I have the log book). I wonder when I read about LGTs breaking 5th gear if that's because they overheat the transmission for long periods (even towing).
I swapped it out for the 6 speed not because of the tranny, but because the R160 diff is very weak. As long as I was changing to the R180 diff I went ahead and did the entire swap. Since 818s don't use the rear diff it's moot here.
"Good Judgement comes from Experience. Experience comes from Bad Judgement"
Owner: Colonel Red Racing
eBAy Store: http://stores.ebay.com/colonelredracing
818R ICSCC SPM
Palatov DP4 - ICSCC Sports Racer
also depending on how heavy your wheels are and how sticky your tires are will make a huge difference. I killed many stock tires at the track just by using softer tries all around.
I found the info in a couple of places:
http://www.rallispec.com/gea_syn_rst1140_t.html
http://flatironsrally.typepad.com/fa...d-more.html#tp
The short answer is the Legacy 2005+ and the WRX 2008+ have stronger gears in the 5 speed line.
"Good Judgement comes from Experience. Experience comes from Bad Judgement"
Owner: Colonel Red Racing
eBAy Store: http://stores.ebay.com/colonelredracing
818R ICSCC SPM
Palatov DP4 - ICSCC Sports Racer
We run RA gears in the 818R. For best results they should be OEM and NOT micropolished.
Owner/builder - AEM Intakes 818R #85
I think I'd rather break something that is contained than an axle that can whip around. My donor (my former DD/AX car) already broke one trans. Third gear acceleration (not on a shift) and it popped. I still run a stock clutch to help prevent some shock loading but when I autocrossed I was able to spin all 4 on launch with Rcomps.
Zero Decibel Motorsports
Check out my new website!
www.zerodecibelmotorsports.com
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I am curious about your statement. First, I'd never heard of micropolishing till now and secondly, I looked it up and there are varying opinions of its efficacy. What about REM isotropic finishing or, as it is also called, Isotropic Super Finishining (ISF)? Combinations of processes like Microblue and REM?
One person said (http://www.eng-tips.com/) "I've had several friends swear that they have seen ~2% gains on a chassis dyno using this."
What's the problem with doing it?
"Scotty, give me all the TRACTION she's got!" Pictures of what I drive till 818R is finished
Track Car Journal on IWSTI (with build info)
looking at doing the 6 speed swap and while I'm at it upgrading the axles ( I have an 06 wrx as a donor) so I am interested in the axles. what all are they including? would you still need your own outer CV parts?
Nolan
65 coupe Gen 3 "Phoenix" build
http://thefactoryfiveforum.com/showt...032#post297032
818 s (with r windscreen ) 350 rwhp. Registered and street legal (SOLD)
Zach (Fate066) is my trans guy and he can elaborate but basically by taking metal off you're increasing lash/slop and therefore failure. I'm sure if they loosen all the wheel bearings they'll see an increase in power too.
Owner/builder - AEM Intakes 818R #85
DSS did my axle assemblies for my six-speed to STi rear hubs. I got their heavy-duty inner CV joints and custom length axles made to couple with the rear STi outer CVJ. $755. I think the axles are 500 HP rated.
From their invoice:
2 - CVJ5114 STI rear outer CV made from 4340 with 32 spline race
2 - Inner CV Inner CV joints for front STi Diff ('05-'07 STi 6-speed)
"Scotty, give me all the TRACTION she's got!" Pictures of what I drive till 818R is finished
Track Car Journal on IWSTI (with build info)
DSS can provide anything you need. If you want just the bars without CVs (as FFR), they can do that. If you want CVs with that, yes, if you want broached hubs, yes, upgraded CVs, yes, I bet they can provide a Koenigsegg inner CV (what on earth you got as a tranny?? ) but they can't go bigger than the biggest diameter possible on the hubs, whichever hubs you may use.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
Can they put a larger wheel bearing in the wrx hubs if bored out? On a side note just picked up a jdm spec C 6 speed!
Nolan
65 coupe Gen 3 "Phoenix" build
http://thefactoryfiveforum.com/showt...032#post297032
818 s (with r windscreen ) 350 rwhp. Registered and street legal (SOLD)