250 WHP Supernatural 3.4 Build (Page 19/47)
lou_dias DEC 21, 11:06 AM
You could go to Archie's F40 6 speed. I have. I've snapped 3 axles but 2 of them were the Fiero outer housing. One was the inner Cobalt SS. I'm running 315mm wide tires with 100 treadware and I've been doing ~50 hard launches per year since ~2011...
La fiera DEC 21, 04:09 PM

quote
Originally posted by lou_dias:

You could go to Archie's F40 6 speed. I have. I've snapped 3 axles but 2 of them were the Fiero outer housing. One was the inner Cobalt SS. I'm running 315mm wide tires with 100 treadware and I've been doing ~50 hard launches per year since ~2011...



Lou you're a BEAST!!
lou_dias DEC 22, 12:51 PM

quote
Originally posted by La fiera:
Lou you're a BEAST!!


I'm just saying that transmission was built for a 290ft*lbs 3900 motor so it holds up pretty good and Archie's kit uses modified for length (turbo) Cobalt SS axles with Fiero outers. So save your Fiero outers...that's the weak link if you go in that direction.
I love cruising in 6th gear on the way to the track...but I guess I'm different... I did switch to an aluminum flywheel but you're still bolting it to a roughly 1" aluminum spacer to work with the Fiero clutch (SPEC 3+). SPEC is inconsistent with clutch package thicknesses so Archie builds the spacer after measuring what he received from SPEC...
wftb DEC 22, 12:56 PM
I am just wondering if any of these transmisions will stand up to the stress of welded spider gears. Stock cars use welded spider gears but this is in a steel pumpkin with a lot more structural strength.
Will DEC 22, 04:20 PM
Splitting the case where it split was definitely from him driving like an idiot. That split is from axial thrust due to the helix angle of the gears... IOW, he just dropped the clutch too hard too many times.

I'd expect axle, diff carrier or side gear failures from welded spider gears, but not case failures.
La fiera DEC 22, 07:17 PM

quote
Originally posted by Will:

Splitting the case where it split was definitely from him driving like an idiot. That split is from axial thrust due to the helix angle of the gears... IOW, he just dropped the clutch too hard too many times.

I'd expect axle, diff carrier or side gear failures from welded spider gears, but not case failures.



Will, please don't call NO ONE an idiot, it shows your foolishness and immaturity. You sound like a very intelligent person but I know for experience that INTELLIGENT people can be stupid, in the contrary a WISE person will never be stupid. You get wisdom over time, it'll come to you one day.

Now, I'm a road course driver not a drag racer. In circuit racing dropping the clutch or power shifting does nothing. I personally take my time shifting to make sure I'm gentle with my equipment. I have never dropped the clutch in any of my cars, that puts a lot of stress on the driveline parts. Lou's kind of racing I understand, the clutch definitely has to be dropped for him to be fast because he can't afford wasting time. As a matter of fact I opted for the bigger camshaft to decrease torque from low to mid and move the power up in the RPM range to be gentle on the equipment.
One thing I tell you and I agree with you on, is the way the case failed. This transmission was taken apart by someone and I can guarantee you he didn't check the pre load on the bearings.
The reason why I say that is because I always thought that the axial play on the shafts was abnormal compared to the MY8. The fact that the case split is proof that my suspicion was correct.
When the trans failed I was not even past 3500 RPMs. It was just doomed to happen. I'm just glad that it didn't happened going into a corner at 130 MPH and downshifting, that would've been a disaster.
I purchased the Kent Moore tool like PMBRUNELLE adviced so when I take the diff to get welded again I can set the preload on the bearings.

But Will, keep your positive criticism which I welcome with open arms, it makes my build better. Thank you very much Will! You are the man!!
Will DEC 24, 11:09 AM

quote
Originally posted by La fiera:
Leaving my driveway sideways and trying to avoid the mailbox on my way out I went up the hill controlling a four wheel drift, the best feeling ever!!
Light turns green and I gently hit the throttle and the sticky Toyos light up and the car goes sideways, shift to second and its still sideways!! I let off and hit the throttle again to keep the car in a straight line and is all good when I noticed a wining sound, like if I had straight cut gears!




quote
Originally posted by La fiera:

I personally take my time shifting to make sure I'm gentle with my equipment. I have never dropped the clutch in any of my cars, that puts a lot of stress on the driveline parts.



Things that make you go "Hmmmm...."

Aluminum work hardens. Over time multiple loading events that push the material just a little bit into the plastic strain range add up to nucleate a fatigue crack, which then grows. The fact that you were under 3500 RPM when it failed doesn't mean anything, because the history of all previous loading events is what led the transmission to fail at that moment.

The fact that the case split at that location in that direction actually contra-indicates bearing preload. If you'd scraped all the teeth off a gear or split the case at one end around the bearing bosses, then it might be related to improper preload.
It really is a case of too many clutch drops. Maybe not all of them are yours, but the parts tell the story.

If you're going to keep driving like that, especially with a welded diff, I strongly recommend the F23, as modern FEA design techniques have resulted in a far stronger and more optimized case.

The F23 from a Saturn Vue has a 4.47 final and a fifth gear in the 0.8's. Get one of those, because racecar, and swap the V6 bellhousing onto it.

[This message has been edited by Will (edited 12-24-2017).]

mender DEC 24, 11:58 AM
Torque reversals (on-off throttle abruptly) are hard on parts and basically jack-hammer the internals. That's why brake-hop with slicks can split a Ford 9" nodular housing on a road course car when it normally would have no issues.

I vote for the F23 as well, I'm switching to that from the 282 Getrag, and I'm keeping an eye out for a Vue for the gearing.
La fiera DEC 24, 02:14 PM

quote
Originally posted by mender:

Torque reversals (on-off throttle abruptly) are hard on parts and basically jack-hammer the internals. That's why brake-hop with slicks can split a Ford 9" nodular housing on a road course car when it normally would have no issues.

I vote for the F23 as well, I'm switching to that from the 282 Getrag, and I'm keeping an eye out for a Vue for the gearing.



I totally agree with you Mender. I built my engine with 3 things in mine because of the type of racing I wanted to do:

1- Throttle Response. I wanted INSTANT response and tha'st how exactly the engine is. Mechanically and electronically I've tuned the entire package to do just that. Is like the time it takes your brain to command to blink, there is no lag.

2-Good Power. No bragging on the power, I didn't want and LS4 because is has a larger mass and its heavier and that would make the car more difficult to handle so I decided to stay with the V6 60* and set a goal of 250WHP. That would make my power to weight ratio very competitive. Also in the rulebook there is a heavier penalty if I opted for the LS4 or any other V8 powerplant.

3. Power Delivery. Like throttle response I also wanted that power to be delivered instantly. If looking at a graph and power delivery was represented as a smooth and long sine wave that was not what I was looking for. I wanted sharp and vertical line going up on power on and a sharp line going down on decel.

As you can see it is not your average build where people look for a streetable car. And taking all three main aspects of the build I can see where Mender is coming from. The on and off the throttle and the way the power is delivered were the reason that contributed to a rapid failure not the clutch drops like Will indicated because I don't do that.

The streetabiliy percentage of my car is only about 15% and thats the way I wanted it. The seat has no padding, its a bare aluminum racing seat from an midget sprint car, I want to be able to feel everything on my but, so I can drive it the best I can and enjoy the ride.

But like Will suggested on that 4.41 F23 sounds like a very good option. I'll start looking into it I wish that someone made a kit of mounts and cables to make it easier to adapt.
lou_dias DEC 26, 02:36 PM
The main reason I have gone with bigger than what is needed is so that I don't have to go back and replace things.
When I was still using 16x8 wheels with 255 wide tires, my 12" brakes were overkill. However, I had a Fiero caliper stick at lock up on me in 2001 and it made me hit the wall head on and I totaled a perfect 88GT at the track.
After going to 17x10 much heavier wheels+tire combination, 12" just do an adequate job...but at least I know they won't lock up. Same went with the decision to go to the F40 6 speed.
If there's one thing I can say is other than some time off in 2014 waiting for an engine installation, I've been at the track every time ready to race since 2011.

If you look at one of Fieroguru's threads, there's a way to change the gearing of the F40...at least you won't be breaking it...
...maybe...

NOTE: it was stock brakes and a sticky front right caliper that locked up on me and turned me into the concrete wall when I tapped the brakes at speed on a curve... Switched to the Rayne/HELD/Arraut 12" Wilwood kit after that...

[This message has been edited by lou_dias (edited 12-27-2017).]