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Old 09-28-2002, 09:57 PM   #1
Andrew
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Default 4EAT Horsepower/Torque Limits, and how to improve them.

I want to begin discussing this. Espeically since, either tomorrow, or next weekend, I will be in the 300+hp/torque club on my RS. I personally have a ProTorque TC and tranny cooler in. But we all know thats not enough when we want to go to the next level.

We know heat is a major gremlin in our trannies. If you can't keep it cool, boom. Would a valvebody, aside from the better shifting, help improve the transmission life under hard uses (lowering temps)? What exactly gives in our trannies and what is our next step to improve it? The planetary gearset is strong, so I do not believe that is what we have to worry about. If I'm not mistaken its the clutches that give...but who offers an upgrade for us?


What does DBRONX or Rally Knight do to bulletproof their transmissions?
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Old 09-29-2002, 12:37 AM   #2
Big Joe
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When I hear bulletproof transmissions, I recall reading that from levelten. It would be nice to have a kit like this from levelten for our trannys:


Stronger clutch plates, I think that would be the next step in building a stronger tranny.

joe

Last edited by Big Joe; 09-29-2002 at 12:48 AM.
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Old 09-29-2002, 12:45 AM   #3
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well when looking at their site, there is basically 3 things you can do... torque converter, valvebody, and the kit you posted. im assuming if we could get a kit made for us such as in the picture which included beefed up clutch packs we could be set. but im not sure, im hardly an expert on 4EATs.

i wonder what the labor cost would be like on something like this.
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Old 09-29-2002, 12:48 AM   #4
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All I gotta say is...hats off to you. I am using the trans as a limit to how insane I am going to make my car, you on the other hand won't be using that as a limit. My hat goes off to you. goodluck in this search.
-Neal
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Old 09-29-2002, 12:50 AM   #5
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I'm glad someone started this thread. Maybe we can start by having everyone that had a failure list what broke and during what event (launching, shifting, just cruising, etc...). It would be also helpful to list what WHP & Torque they had. Like Andrew, I'm very interested because I soon will be over 250 WHP and that seems to be the prerequisite to the "Broke My Tranny at the Track Club"

Russell
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Old 09-29-2002, 12:52 AM   #6
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Well I will be entering the 300+hp/torque club either tomorrow or next weekend. I don't want to blow the tranny with only 300 ft/lb. This is from a 2.5 btw.

I don't think I'm going to go to the track or launch the car till we go a little deeper into this thread. I know Kevin Thomas put his tranny through hell several times before it went 6 feet under. Kevin, did you have a cooler before this happened?

Last edited by Andrew; 09-29-2002 at 12:59 AM.
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Old 09-29-2002, 12:59 AM   #7
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I think if there was enough interest, we could ask levelten to produce such a kit for us. I just finished reading an article on their site regarding the build of the Supra autotranny, nice reading.

I've learned from those that have already blown their trannys, heat and high torque launches reduce the life of our trannys.

What we can do right now:

1. Increase the frequency of changing the trans oil.
2. Use quality oil.
3. And the hardest part, we have got to know the limitations of how much horsepower and torque we can lay down safely when launching.

pondering what my next mods are,

joe
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Old 09-29-2002, 01:04 AM   #8
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Ok, well. I was looking up some stuff on rally Knight...because I wanted to read about there auto trans...

I took this clip from something I was reading from a set of posts about somthing else.

Quote:
Originally posted by Digital_Boy

Give Jon Ryther, aka Rally Knight a PM. He's tested the 4EAT full manual conversion last weekend at the Ramada Express Rally. It performed flawlessly, unlike the two turbos that broke on him. It's been reworked to handle the prodigious torque the car produces (500+ lb/ft from an EJ25), and has flipped the torque bias from 90/10 f/r to 10/90. Cost for the full on conversion is in the mid $3-4K region. But, you'll have a nukeproof auto trans that shifts like a manual.
I am going to look into this, I suggest you might wanna also.

-Neal
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Old 09-29-2002, 10:34 AM   #9
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Don't forget the differentials. Rifts blew his center and rear when the tires hooked up at max torque. I've read a little about Quaife. What other options are available for the 4EAT?

And I'd love to hear more about what Rally Knight did.

Padre
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Old 09-29-2002, 03:13 PM   #10
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Quote:
Originally posted by Andrew

I don't think I'm going to go to the track or launch the car till we go a little deeper into this thread. I know Kevin Thomas put his tranny through hell several times before it went 6 feet under. Kevin, did you have a cooler before this happened?
When my tranny was going bad, the only thing I had done prior to it starting to go was synthetic fluid added and a tranny cooler. One month before it finally went, I had a hydrosystem (valve body) from Level 10 installed.......by Level 10. I actually drove to their shop (3 hrs away) one morning to have it done and had a nice time talking to Pat Barret (the owner).

When the transmission finally went, the clutchpacks/plates or whatever you call them gave way. The friction surface was frictionless.......worn. I went to Benchmark Transmission to have my clutchpacks/plates that are made of a paper-like surface/filament replaced with metallic ones. I never had a problem since.

The reason why my tranmission 'went' was because of heat build up between the shifting. Running big horsepower between shifts while still flooring the car causes problems (at least it did for me). It got to the point where big fireballs would shoot out of my exhaust because the clutches weren't engaging quick enough between shifting. Looks cool but the tranny was pissed off. The shifts got longer and longer (especially between 2nd-3rd gear) until it wouldn't shift any longer in that gear. This is what I mean by saying my tranny 'went'. It no longer shifted.

I never got the pictures Pat Barret said he was going to send me of the tranny pieces and shredding that was picked up on the tranny filter magnet. He was supposed to send it to me via email. The pieces are normal but not the size that I had. Could've made a nice bracelet or necklace out of it.

So......tranny cooler, synthetic fluid and quicker shifting (valve body) is what I'd recommend....alongside with the TC mod. It would be pretty strong then. Only thing left would be the clutchpacks/plates being upgraded to a different surface, like the pic above. All of these help in reducing heat.

I still don't have a Pro Torque TC on either of my cars because I'm a fool. However, the shop that rebuilt both of my trannys (Benchmark Transmission) have upgraded the clutchpacks to metallic surface, synthetic fluid and tranny coolers as well as 'supposedly' upgraded the torque converters. I never really noticed a difference in the torque converter but being N/A (at least the OBS when I was testing the TC) is a different beast than a turbo.

I'm saying this to let you know that Pro Torque or Level 10 isn't the only game in town. You may be able to get a valve body job done by a local tranny shop. I'd go with ProTorque on the torque converter though based on the great experience people have been having with their product here. I do enjoy the shifting of my XT6 now but the OBS's shifting is sharper and harder but both firm. Level 10 knows their stuff. I believe they (Level 10) can vary the sharpness and firmness of your shift to your liking. I told them to go the max that would be suitable for the street. The mechanic had an evil laugh as him and Pat looked at each other and he said, "Don't worry, I'll take care of you". Now I know why.

Hope this helps!

Last edited by Kevin Thomas; 09-29-2002 at 03:25 PM.
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Old 09-29-2002, 08:06 PM   #11
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@300 HP you are right on the edge of the 4EAT. Unless you do some TCU mods the tranny will start to slip. If you just continue to increase the line pressure to keep the clutches from slipping you will incounter down shift problems as I did with a fully built Level 10 4EAT.

My guess is 250 hp is about the street max for the 4EAT. If you want to talk to Knight Rally, they have put over 500 through a highly modded 4eat. Not a street tranny, this is a manual shift slam banging mother to drive.

Been there done that ... and it ain't cheap
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Old 09-29-2002, 08:47 PM   #12
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How can someone get in contact With Rally knight about the trans? Will they do work on private cars?
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Old 09-30-2002, 12:18 AM   #13
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Iyou guys are serious about building or buying a tranny that will hold up, I have some info for you.

The type of 4eat you are seeking is being made right now and has been for some time. We are having the new version auto built for our 750hp drag wrx and was promised the best. But the people doing the work are known for bulletproof trannys, so we are not worried.

Here's the kicker: they cost almost $7000. They will need to be rebuilt often(every 12-18months) depending on mileage. But the rebuild is only a fraction of what the tranny costs. The clutch packs wear faster, but are very, very strong. Several vulnerable parts are replaced with new, machined parts. It comes with a torque converter, but you will need to accurately know when your turbo comes on boost so certain adjustments can be made. They are built differently depending on max hp and torque levels, but it has been said that 800hp is about the max the tranny can handle.
There is a core on these, so you would have to send yours back. If you have a core to send and have built, the price is much less. The ideal core would be from a new wrx auto of course, but any 4aet after 99 is good. It's the old (better metal in the case) thing. Time frame is about 2 months, maybe slightly longer because of the baja coming up.

Sorry I can't share the builder's info, we have too much money invested in development. If you are worried about quality and ruggedness, as I said we are going to be using this tranny in our 750hp drag car and by late summer of next year should be running high 8s. This may seem like a low number to state without the car ever turning a wheel, but if you could see the the car and the level of build.....We plan on taking the car to almost all of the Import drags and some NHRA rounds next year. First time out should run a low 10 or high 9. And this is before we actually start dialing the car in. We specifically stated we needed a tranny that would withstand this and the answer was "No problem".

I have been tuning on cars, of different makes not just subarus, for some time now and the builders are known as one of the best auto transmissions builders in the world. Failures are very few and quality is increadibly high. These are going to be the bulletproof subaru trannys everyone is requesting.
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Old 09-30-2002, 01:26 AM   #14
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First, thanks guys for getting the ball rolling very well on this thread.

I think 7k is a little too much for most of us. Myself, I'm not looking for somethign that can withstand 750hp, i just want somethign that can take 300-400, and it sounds like the valvebody should be my next step and maybe turning down the boost until i can build the tranny to hold the power.



having beefier clutches, is that something a normal tranny shop can do or do we need a company like level10 to build them for us?
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Old 09-30-2002, 02:48 AM   #15
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$7,000? Good lord I'd just buy a dog box M/T and go back to doing the shifting myself if it came down to that.
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Old 09-30-2002, 03:18 AM   #16
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i encourage this and beleive 7000 is a great price for 750 torque rated tranny(i hope since you stated it was HP). but this is an all out race tranny you can't really compare to other options... such as dog boxes mind you dog boxes need to be rebuilt often too...
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Old 09-30-2002, 11:24 AM   #17
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The biggest thing for reliability that the common person with a 4EAT can do is to reduce torque on the shift. That's done 2 ways.

Drop timing

Drop boost.

In the last 250-500 RPM before a shift, I'll cut boost significantly, and add in a bit more fuel, this will cut torque quickly, allowing for a smoother shift.

So you loose a little bit of high RPM horsepower.... oh no.. the pain..

Jorge (RiftsWRX)
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Old 09-30-2002, 11:56 AM   #18
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Actually, this is not just an all out race transmission. It does have to be manually shifted, but will still behave much like a stock unit. The shifts are a little harder and the stall is raised(depending on your specification), but it is still very streetable. The biggest advantage is the reliability it offers. We plan on doing about 75-100 hard launches each month with this unit.
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Old 09-30-2002, 01:20 PM   #19
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well one of my requirements for a streetable transmission is that it last longer then 12 months... anything that has to be built with the frequency of your proposed transmission is (for me) an all out race tranny or a headache... but the transmission is said to hold a huge amount of torque (can it?). Btw how much torque can it handle... trannys aren't broken with hp but with the torque
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Old 09-30-2002, 10:21 PM   #20
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Well, we figure our engine will have over 650ft lbs of torque, so it is being built to handle that. I doubt you would need more than that. As for the rebuild, that's the nature of the beast. Everyone wants something they can't get, and an indestuctable tranny without proper service is unheard of. Those clutch packs will need to be replaced every so often so the rest of the components don't get trashed. It's not as much of an inconvienence as you would think.
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Old 10-01-2002, 12:16 AM   #21
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I'm just looking for the 4EAT to handle 300 lbs of torque. I know I want a streetable transmission and am willing to service her more often but to have to keep rebuilding it is way too much than I would want. What do I need ?
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Old 10-02-2002, 11:30 PM   #22
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I dont normally post but this is something I know a great deal about. Knight Motorsports has alot of experience in all transmissions offered for the Subaru. From our experience, the automatic based transmission can handle greater amounts of torque, are more reliable than any currently availble manual transmission for the Subaru.
Lets look at the at the costs of each type of transmission offered. A good dog box manual transmission will, for the gearset set you back roughly 5,000 american, this does not include the case. I will never recommend that you install the gearset yourself, so figure on at least 750 for install. I will give the actual removing and installation of the transmission to the enthusaist if you want to save money. If you want a LSD in the front differential, figure about minimum 750. The center differential will set you back a further 750 to 1200. So now are up to 7250 if you do all the removing and installing yourself. If you want a Sti six-speed then start at 14,000 and get 450 for new front axleshafts and 525 for a new center driveshaft and crossmembers......Do you really want the total?
Pro's we have all driven manuals I don't have to dicuss this.
Con's.1 For some cars turbo lag is increased by improper gearsets and ratios, that is why rally cars have anti-lag systems. 2 Its a dog box and really is a pain for the street and noisy. 3 Drive a high powered clutch in traffic and let me know.
Reliability is decent for a street car that ONLY sees OCCASIONAL hard use. If you rally fiqure 3-4 Rallys tops. The top teams recondition the manual EVERY rally. Drag...maybe 2-3 EVENTS. Thats pretty good right. Oh and if it fails then you get to do the above price again.
The automatic based gearbox 4EAT will in full race trim cost about 7,500. This also includes the shifter,trans cooler,torque converter to your specs, flex plate and all fluid lines installed at our shop. Yes that is a complete price. Includes Front LSD and a adjustable center clutch pack 90/10 front/rear to 50/50 front/rear(there is no diff in the center on 98 and newer autos). The WRX auto transmission has a center Torsion style center diff and can be adjusted to 90/10 front/rear to 45/55 front to rear. The 98 gearbox shifts manually only but the newer models 99 and up will have both auto and manual modes. Cost is decent. It will survive up to 800 ft lbs of torque.
Reliability. The torque applied and the duration will dictate how long it will last. Our rally cars put out 550 ft lbs of torque and are driven for 500 miles minimum before each race at normal street and highway speeds. Last year we had a transmission go 9 races before failure. That totaled 6,000 street miles and 920 miles of stages. The failure was due to the oil pickup being squashed. Also when and if it fails completely the cost for a complete rebuild is 3500. A standard preventive timed overhaul is 1200. I do PTO to save the investment. For rally use about once a year usually in the middle of the season.
Lets look at Pro's and Con's.
Pro's 1 The action of the torque converter lets you build boost and maintain it without affecting vehicle control (ie I can give throttle and stab the brake at the same time without it jarring the car) 2 You do not have to lift off the throttle for shifting, heck you can shift to any gear at any time regardless of RPM. Although I highly discouage this, motors find this rather unfriendly. 3 You can leave your foot on the brake at all times for left foot braking (no clutch pedal) 4 The center clutch pack enables disengagement of the rear axle for handbrake turns 5 You can drive your 750 hp firebreathing monster in traffic in LA
Cons 1. There are only four gears (we are working on that, but lock-up helps) 2.You will have to change the fluid often and synthetic isn't cheap because you will need about 10 quarts 3 it is just a little heavier than the manual about 75lbs 4 Your right leg might get stronger than your left leg because you don't have to press on the clutch now requiring you to get a gym membership
As a final note we can build autos to a lesser degree if you want. A manual shift 98 box with TC lock-up, center on/off control, upgraded torque converter and flex plate, front LSD, trans cooler and shifter will set you back about 2700 installed at our shop. It is good for 300 to 400 ft lbs.
Thats about all I have thanks
Jon Ryther Knight Motorsports E-mail me for more info as the web hoster is taking forever to set-up
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Old 10-02-2002, 11:39 PM   #23
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See, $7000 is not too much for a tranny that will handle what you want it to. Thanks to RallyKnight for getting on here and telling it like it is.
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Old 10-02-2002, 11:51 PM   #24
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we never said 7k for a RACE tranny was bad! Thats a normal price, but 7k for a STREET tranny is absurd. most people on here are only looking for something that will handle 300-400 ft/lb.


rallyknight, how much would it cost for just an upgraded clutch pack? or how much for your tranny upgrade if we already put in a torque converter ourselves?
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Old 10-03-2002, 12:08 AM   #25
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Great information! I know where to go if and when my tranny goes south.

Quote:
From our experience, the automatic based transmission can handle greater amounts of torque, are more reliable than any currently availble manual transmission for the Subaru.
I love this post!

joe
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