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Going to a 6 speed
I blew up my Subaru 5 speed for the third time yesterday at Sonoma Raceway. I haven't opened it up yet, so I'm not sure what is rattling around. It wasn't under much load when it popped - at least relative to other locations on the track. Video of it going at the end of my Factory Five 818S vs Lotus 2 Eleven video (just before I turn on the hazard lights and windshield wiper). It was running at 270 degrees, so perhaps that has something to do with it.
99% going to order a 6 speed from ZF Design on Monday.
Any last minute words of advice?
Looking for inspirational photos of cooler mounting locations.
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Originally Posted by
Hobby Racer
Did you install a cooler? A picture or two would be appreciated.
I'm also looking for pictures of VCP K-Tuned shifter transmission brackets.
My understanding it the 6 speed is 80 pounds heavier than the 5 speed. Is that right? I'm imagining a new 80 pounds at the rear end is going to change the handling. Any feedback on that front?
Last edited by Dave 53; 05-14-2023 at 12:13 PM.
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Senior Member
Originally Posted by
Dave 53
Did you install a cooler? A picture or two would be appreciated.
I'm also looking for pictures of VCP K-Tuned shifter transmission brackets.
My understanding it the 6 speed is 80 pounds heavier than the 5 speed. Is that right? I'm imagining a new 80 pounds at the rear end is going to change the handling. Any feedback on that front?
My 6 speed setup was only 40lbs. heavier than the 5 speed it replaced. Lot's of 6 speed pics and details in my first build thread starting here. Frame mods for the 6 speed install
K-Tuned shifter, ZDB bell cranks, coolers, it's all in there.
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Thanks Hobby Racer! Very helpful! I certainly will be asking questions as I go along...
First question) I'd like to do the chassis modification before the 6 speed arrives. Before I blindly copy your method, do you think the same pattern will work with an H4? I ask because I assume your tranny sat a bit further aft connected to an H6.
6 speed chassis modification.jpg
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My frame mod
Just as another data point...
I have a 2006 STi engine and 6spd trans. Here is a pic from below of my frame mod. After a little analysis, I kept it a bit simpler than others; just cut out the fwd part of the X and added the two lateral bars. Though I agree it's hard to argue with a little more steel.
I measured around the trans oil pan, which you can see hanging down between the lateral bars.
rear on rack.jpg
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Originally Posted by
Dave 53
Thanks Hobby Racer! Very helpful! I certainly will be asking questions as I go along...
First question) I'd like to do the chassis modification before the 6 speed arrives. Before I blindly copy your method, do you think the same pattern will work with an H4? I ask because I assume your tranny sat a bit further aft connected to an H6.
6 speed chassis modification.jpg
In hindsight I would have done the same as driveslikejehu and done a simpler modification, plenty strong.
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I have also done the 6spd frame mods used by Hobby and have the VCP K-tuned shifter brackets. I plan to install an oil cooler in the near future for track use. I have pictures of it all in my build thread too.
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Here is a link to my latest and best transmission cooler. I would suggest this design over the first generation cooler setup in my build.
New transmission cooler setup
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Your cooler design looks awesome! Unfortunately, I have a small fraction of the tools you do. Near zero fiberglass skills. Fortunately, I can fabricate with steel. I'm very proud of my oil cooler project and I'm sure I'll come up with something for the tranny cooler heat exchanger. oil cooler.jpg
I got the broken transmission out and open up. Another pinion gear failure. 6 speed ordered from ZF Design.
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Update.... Got the 6 speed installation done about 9:00 Saturday night. After a short test drive, I signed up for a track day starting 11 hours later on Sunday. Thought I'd share a couple of pictures of the cable brackets I fabricated since I reinvented the wheel. trans bracket 2.jpgtrans bracket 1.jpg
The 6 speed is a ZF Design. We had extensive talk about what gear ratios to use and settled on a close ratio setup. I knew all my shift points on track would be different and boy were they. During the second session, my engine blew up.
There are a couple of theories as to what happened and several lessons learned. The quick answer is after a review of the GoPro, it seems that while learning the new shift points with the close ratio gears, I was revving the **** out of the engine and it over heated.
Last edited by Dave 53; 06-13-2023 at 01:50 AM.
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SO sorry to hear about the engine. I've been there a few times myself, not pleasant but you soldier on and make it better next time!
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Dave, was your engine rebuilt before your build or did you do as many do and drop in the donor motor with only a minor refresh?
Kit #361, arrived 10/2015, still in progress
818C highly modified, corvette suspension
Estimated completion summer 2023!
1989 turbo Supra 5 sp
2017 Tundra
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Full long block rebuild with forged pistons and rods. 1050 injectors and bigger turbo (not sure of size off hand). 18.5 psi max boost. 265 whp. 23 track days and 14,000 miles with no previous issues. Motul oil change every 8-9 track hours with Blackstone analysis.
Hope to have the engine out and to my builder by mid next week for an autopsy and game plan for moving forward.
A few lessons learned...
* The close ratios gears will take a bit longer to get use to than I anticipated. I need to use some analytics vs seat of the drive suit butt dyno.
* I should have overlayed the rpm range for each gear on top of the dyno graph. Shifting at redline might not even be the fasted strategy for maximum area under the curve.
* Reviewing the GoPro at home was telling. I should do it after every session. I would have noticed I was over revving and over heating the car in the first session. And useful for immediate driving feedback.
* A shift light bar would be helpful. On my go kart, I had one programmed to tell me when to up and down shift - mistakes I was making after reviewing the video.
* I had always prioritized oil temp over water temp because oil temp always seemed to be the weaker link. Not in this case. Water temp hit 241 (not good) and oil temp never hit 265 (warning light trigger). Oil temp alarm before water temp alarm is not a hard and fast rule. Very curious how water temp got so out of control without driving oil temp into the red too. Cooling system issue?
* I never looked at the water temp gauge. It's hard to check gauges and especially on Thunderhill West because the longest straight is very short. But that's not a good excuse. I put blue (sometimes red) painter's tape notes all over my dash. I need to put a gauge check reminder across the windshield.
* Since timely reading of gauges is hard, I have bright conspicuous warning lights for low oil pressure and high oil temp. I need to install the high water temp I had made.water temp light.jpg
* I have a Mishimoto radiator, but no ducting. Need to fabricate ducting.
* As soon as I started hearing concerning noises, I should have pulled off the track and instead, I limped it back to the pits. Luckily, I had no leaks, but I could have contaminated the track and less damage.
* I had a 2 hour tow truck ride with a wonderful gentleman from Afghanistan. He was telling me about conditions there after the Taliban took over his city and what he lost. Perspective.
Last edited by Dave 53; 06-13-2023 at 06:52 PM.
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Sorry to hear you lost your engine. I've lost plenty of them. I'm a firm believer in a datalogging now. Even better is a datalogger connected to a dash display that you can setup alarms on everything important. Being able to go thru your logs between sessions or at least daily will save you all kinds of grief. It's really hard to watch your gauges while going around a corner but that's where you need to know you are losing oil pressure. Or knock, or many other critical values.
"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
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Yes, I will start reviewing data log after every session.
Reviewing the video of my driving the next day is always informative to see areas I could improve. Why wait until the next day? I'm going to start reviewing after every session.
I have a bright peripheral vision warning light that will illuminate if oil pressure drops below 10 psi even for a spit second. But the light will flash for just a split second, so not much help while driving if it dips in a turn because I won't be concentrating on it in a turn or really ever on track. I think I just figured out a way to make the light stay on for X seconds after it triggers even for a split second with a programable timer I just found on Amazon. And flash. So even after oil pressure recovers, the light will still be on and flashing for X seconds in which case I will see it. (Amazon: Mini timer time delay relay)
Turns out I spun a main rod bearing and somehow, bent the crank shaft. The build sheet I had for the motor was vague, so I've never been sure what was in it. Turns out the previous builder, Speedy Roo Motorsports in Auora CO, skimped out in a few areas. Also, compression ratios were exactly at 10% variance between cylinders. And with a hybrid 2.0/2.5, you need to lower the compression ratio which Speedy Roo failed to do and my tuner had to "tune around it". At least now I'll know exactly what I've got in the motor which will be parts appropriate for how I'm using it. Going with ACL bearings, Wiseco pistons, STI crank, GSC guides and valves, 11mm oil pump and few other upgrade bits. Chamber matching the heads for proper hybrid compression ratio. Between the 6 speed and now this motor build, my retirement plans just got pushed back a bit. The good news, in addition to knowing I'll have a proper motor, the long block should be done tomorrow. Still have to wait on many parts including getting the turbo back from a rebuild which might be the biggest hang up. Shouldn't be a problem making Aug 6 Laguna Seca.
Last edited by Dave 53; 06-22-2023 at 03:31 PM.
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