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Torque Converter Install and Question
First look below at my signature to see what I have in my Mustang.
I had a 3000rpm stall converter put into my Mustang the other day. This converter is a non-lockup converter. I also have a Transgo shift kit in my AOD tranny. Well, the car used to be pretty jumpy around 30-35mph I could stomp on it and it would throw you back in the seat and now it pretty weak. I also had to have the tranny filter and fluid replaced because the fluid in the converter was pretty dirty. I guess I don't know enough about how the whole torque converter thing works exactcally. I guess with a higher rpm stall I was expecting alot more than what I have. When ther tranny was dropped to get the converter in is there something that needs to be adjusted? I need your help with this. Thank you all John |
First of all, something must have been done wrong. I swapped out my stock TC for a 3000 stall TCI street fighter and it turned the car into a beast! I am also running the transgo kit on my AOD and I switched to 4.56's from my 3.73's.
The only thing I can think of is that your torque curve starts lower than the converter stall and that will negatively affect performance. Otherwise you should be whipped into the seats as much as before. My transgo kit seems to favor higher gears and is less prone to downshift. This might be your problem, running in a higher gear. How are the shift points and gear selection? Maybe a tightening of the TV cable is in order to leave you in a lower gear. |
I have 3.73 gears in my Mustang and I guess I'm not sure as to what the issue is. Is your StreetFighter a lock up or a non-lockup. I was told that I should use a non-lockup with my setup. I was really expecting a huge difference. It seemed so much better with the old converter in it with the exception of the off the line start. I can really break the tires free easy and the shift points seem a little high now. Before the install I could really feel the shifting and it was hard, now not much. Do you think it needs something adjusted.
Thanks all. |
Actually, I'm running a lockup, which is why I went with such steep gearing. I have acceleration in OD!
Nonlockup should give you torque multiplication through all your gears unless you're driving around above 3000 rpms and then the converter would be stalled and you wouldnt see any difference. I dont think there is anything to adjust other than shift points. Maybe tighten the TV cable and achieve better shifting and see if operatring in lower gear or staying in lower gear longer produces the umph you are looking for. If the verdict is that the 3k stall is worse than the stock converter, then I believe that you might have gotten a bum converter. I got ripped off once by buying a 2k stall on ebay which was nothing but a stocker painted purple. Was your TC from a reliable source? |
I bought the TC from a guy on eBay that builds them. I read the replys that he had and they were all positive replys and the guys hasn't had a negative reply. He recommended a non-lockup because of the shift kit and the gearing. I'll try starting in low 1 and working my way though the shifts. I could start in 1st gear (Low 1) and shift to second (low 2) and squack the tires. And even leaving it in drive it would shift hard from first to second. Now it wants to run in the higher rpm range and I can't really feel the shift like before.
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Sounds like?
It sounds like the convertor never really stalls or "couples" as they say. It may be slipping all the time even at and over 3000 rpm. I'm only guessing of course, but that's what it sounds like.
Rev |
I dont know about you guys...but I have yet to run across anyone on ebay that doesnt have phenomenal ratings =) . I think the system is skewed. The guy who sold me the stock TC had phenomenal ratings. Bottom line is TC's are such a quality dependant item that it only makes sense to buy from a reputable company that can guarantee the quality. I was out $200 bucks on my ebay'ed converter. Had I bit the bullet and spent $300 I could have the TCI that is riding under my car right now.
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This is what the guy I bought the converter from replyed to my question that I posted here. What do you think. Can someone tell me what I would need if this is correct?
3000 should not be too much for a healthy engine but it will take the firmness out of the shifts i suggest increasing throttle pressure to 35 lbs and setting the transgo with the hardest shift pattern available for firm shifts also you will notice this converter is not direct drive so you will not feel the bangs in 3rd and 4th gears but you will have more power there what stall rating did you get with your gears the car it was tested in went to 3100 before the tires would spin i would guess you should have gotten about 3000 with your gear ratio what servo are you using i highly recommend the A overdrive servo it is possible that the added torque going through the input shaft could be causing your clutches in the trans to shift on apply also what rpm are your wide open throttle shifts coming in at alot of these trannies had really early shifts and the fix was to use either the high rev governor kit that is included in the transgo aod-hp shift kit or use a supercoupe governor do you have any extra clutches in your transmission? from my experience the only means of making firm shifts in these transmissions with a high stall torque converter is by adding extra clutches and a wide band but if you are going to do all that go for the wide gear ratio too and you will love the results.Bold |
I went from the B servo (stock) to the "A+" servo and noticed only a slight increase in "bang" going into 4rth. I would reccomend it but I dont think it will solve your problem. The TV pressure should be 35 psi already. I installed the transgo AOD-HP kit with the most agressive settings and the high rev governor. It shifts nice and firm.
How old is the transmission? The bands _could_ be worn ,as the man said, but... if it was a screamer before, then it should be a screamer now and you cant scream much on worn clutches. A quick fix would be to keep tightening the tv cable a notch until it shifts as late as you want it to. Dont go too crazy or you will overpressure the system. Did the guy implicate that he tested it? Was there oil inside the converter? That is the only way to test it is to drive around on it. If it was squeeky clean inside then I doubt it was tested. Maybe there is something I dont know, but I'm pretty sure you need to fill it up to test a converter. Quote:
I say install the highrev governor if you havent already done so (you can do it with the AOD in the car, just pull the tailshaft housing). Then tighten the TV cable to get your desired rpm range. If still no luck, get upset, put your old TC back in and ebay off your current TC as a "kick@ss 3100 stall converter!" and charge $100 more than what you paid for it. =P |
When I bought the car the work on the tranny was done a year prior to me buying the car. I'm not 100% sure the shift kit is a Transgo, but I know there is a shift kit in it. When it would shift from 1st to second it would shift hard and squawk the tires. Now it revs high and the shifts when I'm in drive are very hard to notice. I believe that is the point of a high rpm TC is to be able to run higher rpm's and stay in the power band. If I'm understanding this correctly. I can bust the tires free without any problems when it was a bit harder before without having to power brake. The converter was installed because I have to have my tranny flushed because the fluid was burned up. I hope the converter isn't burned up. I'm not saying that I don't feel a change, I do, but I was expecting alot more throw back into my seat feeling and it was better with the other converter.
Thank you, John |
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The purpose of a torque converter is to allow the engine to spin up more before engaging the drivetrain. Your rpms are controlled by your shift kit and the tv cable...shift points. A low stall converter will start the car moving at lets say 1200 rpms and a high stall will wait till 2000. This is what the official line is. I, personally, have never seen that advertised behaviour. I'm not sure what the 2000 and 3000 stall number engineeringly implies but it is not the speed at which the car starts moving. My car will move at 600 pms when I take my foot off the brake and it will move at 2000 rpms which is my cruising rpm. This is why I'm like "huh" when the guy said to you it starts spiining tires at 3100. Actually, since it is no-lockup, maybe you get converter slippage when you gun it now since you are not near the converter's stall speed and this robs you of tirebarking snap that you used to have in 3rd when the direct drive shaft locked up. |
No No My Mustang is moving at idel speed and it just seems the rpms are moving up faster than I am and I'm not moving as fast. Kinda like some said it's almost like it's slipping some. I'm not sure when the tires break loose maybe around 2600 rpm's. I guess that I was moving faster with the old TC is because it was a lockup type stock TC. I can feel like I'm accelerating faster at higher speeds, but I don't get the throw back that I was looking for. Maybe that is just getting the TV cable adjusted so the shift points are harder. What I hear I will lose some of that because the tranny is operating at a higher torque curve. If I'm wrong please someone correct me.
Thanks for everybodys help and advice |
I just wanted to state something....
But please understand this is not a flame or anything like that. All the info so far seams to be accurate (because, I claim not to be a converter or transmission specialist.) but the statement made by Crazypete: "gearing of the car has nothing to do with the stall speed" ....is completly incorrect. Besides the torque curve of the engine you must account for: vehicle weight... gearing... any power adder.. cam shaft profile... (how big and how much duration... cylinder heads.. etc, etc, etc... A good torque converter company will take all of that info, plus about 20 additional questions into consideration before designing a converter for you or matching you with a proper one. Due to the FACT that any of those things can alter and change your final stall speed! I have spent well over $2,000 on VARIOUS converters and finally bought one from Lenny at TCT converters and now I am completly satisfied! You get what you pay for! My .02's |
Another common mistake is, asking for a certain size converter or stall speed. WAY to many variables! Leave that to the pro's to tell you what you need! Explain what you have, and the intent purpose of the car. Then you will get what you need. It's almost like asking for a 3/4 race cam.
Don't get me wrong...there are alot of us here that have a very good foundation of approx what size and what stall speed we would need for a combo, but leave it to the pro's and question their response if you don't agree. |
I guess the gearing affects how the TC sees the weight of the car, so you are right!
Though with his combo, he should have seen similar results to mine since the cars should be in a similar class (I had 3.73's with that converter before my gearswap). So what is the consensus about the "standardized" TC's like the B&M's and tci's. I love my tci and they told me between 2800 and 3200 stall for my application. I vote that the car in question is having massive converter slippage. Do converters ever have bad/weak.....clutches(?) in them? |
quality
This is also not intended to offend anyone, but here is my opinion. I have also had a few different T.C's in my stang, and was unhappy with all of them. My first "performance tranny was a B&M....and I could tell no difference with it over a stock.
This is one of those places I really would advise.....save ur money...and get a quality piece. You really will get what you pay for concerning T.C.'s. They will ask u lots of questions about your car....they know what they r doing if u talk to the right places. It sucked dropping the cash for the T.C. I bought, but I will say it was the best performance decision I made (except for gears). Ryan |
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Like rwhite65 has mentioned...same your $$$ and get a good converter. For the power range he is in I believe the Precesion Industries would be fine. Get it NEW! Comes with a 2 year warranty and if you need a stall change for what ever reason, they will change it for free, the first 2 years to the orginal owner. I honestly broke 4 of them! People swear by them, but once yoy start going into the 10's using a trans-brake....they aint worth shit! IMO. Everyone I have delt with claims the same thing. You need to dtep up to a $1,200 converter on up. Like TCT, Neil, ATI,Cone,etc. |
I am no where near the 10's, but I think it did come with a warranty. I would have to look at the paper work.
Ryan |
Yea some people have great luck with them...even in the 10's but I didn't. :(
At this point, I would have to say it would be foolish to spend the money for a TCT, Neil, ATI, etc units due to the amount of $$ involved. But a PI converter is what I believe he should be looking at, with the level of his current mods. |
What is a PI converter or what is the mfg. name? I guess I would have needed someone to drive the car before installation and after to see what I'm talking about. It will roll the tires with no problem when I stomp on it but the throw back effect isn't what I expected. I've been told that I will lose some of that because the car is running in a taller rpm range.
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ok time to stop the confusion i personally built this converter using a 10 inch c4 core so it's stall should be the same as those found in a 10 inch c4 converter
it is not a reworked stocker obviously as it is a 10 inch converter there really aren't any components in that converter that can fail it has the largest sprag ever built by ford good for about 700hp all the fins have been reinforced and it is completely rollerized i have decided to no longer build these aod torque converters there is too much confusion and everyone thinks they have gotten a faulty unit even when it works exactly as it is supposed to i question if the clutches in your transmission can handle the blow of the extra torque multiplication which could cause sloppy shifts and i also wonder if your band is working properly if the band slips 2nd gear would not pull hard causing the feel you are getting around 30mph that converter is built to be efficientand should be near a 1-1 ratio by 3800rpm however it does not pull hard below 1800rpm as i told you in the first place if the stall is too much send it back i'll swap in a low stall stator but you'll have to pay shipping both directions because i didn't make profit from this converter anyway all the parts in it are new from sonnax and i put at least 10 hours of labor in this thing believe it or not building that precision front cover was alot of work for future reference the only converters i will build for aod transmissions are those identical to pi or edge converters using a complete kit from sonnax and the cost would be about 650 dollars if you want to go with one of those send me that converters back and i'll refund the 150 you paid for that converter from the cost |
Confused?
Is this convertor supposed to stall around 3000 or is it 3800 (nominally)?
Rev |
it stalls to 3000 it is at maximum effieciency at 3800 max meaning at 3800 rpm it should deliver a 1-1 ratio
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Flash stall?
I thought that if the flash stall occured at 3000, then the convertor was "coupled" and delivered about 90-95% efficiency from there on out to red line.
From your description, I'm wondering what happens beteen 3000 and 3800. Rev |
it becomes more efficient the closer it gets to 3800 and 3800 could be a high figure on that it could be most efficient by 3400
the true stall of this converter after flash has occured is about 2700 like i said before this converter shares all of the stall controlling components with a 10 inch c-4 converter i have not modified any of those components except to make it work with an aod transmission which with 2 input shafts is a tough job |
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As goes for a converter with 90-95% effieciency...wouldn't that be a real effiecient converter? I generally thought when you got a loose converter (3,000++) your level of effieciency would be at best 10% after stall speed unless you spent the big $$? |
i didn't build this converter for his application i built it for a friends car and they decided it was too much for their daily driver so i built them a 12inch converter instead .
i could spend hours explaining torque converters to you and still most would not understand what i am saying without seeing it so i'll start and finish it up later. the parts of the converter. pump or impeller pictured here on the right. and the stator is on the left on top of the turbine. these components control stall and efficiency this particular model is built for the 4r70w and aode transmissions. the pump has a few factors controlling stall and efficiency the angle of it's blades (this is a very high stall unit) control stall alot . if the blades are straight stall will be less and if they are pitched the opposite direction they will be even lower. also it's diameter and depth control stall this is a deep converter which will become very efficient (90%)at high rpm but is not very efficient at low rpm. the stator is the aluminum piece you see it has a sprag inside of it that turns freely one way and not at all the other. when the sprag is locked the converter is on high stall. when it is unlocked the converter is as efficient as it can be. the fin angle of the stator greatly increases stall as well as the distance the stator is from the turbine and impeller further away from the impeller will decrease stall and further away from the turbine will increase stall. the turbine is the other set of fins you see it drives the input shaft of the transmission. the depth of the turbine also helps control stall and efficiency as well as brazing of the components as you see here improves efficiency. the distance the turbine and impeller are away from each other greatly controls stall and efficiency normal clearance is .100thousandths or 1/10th of an inch converters can be built as close as about .060 thousandths but they have to be very precision parts and usually the brazing process time and use and even factory standards don't much allow for these clearances the easy way to make a converter stall is to add clearance between the halfs at 3/10ths of an inch a 1500 stall 90% efficient converter will become a 2500 stall 75% efficient converter compared to the 1/10th of an inch normal clearance however making stall this way has the most dramatic influence on efficiency so is not desirable the best ways to increase stall and to machine the stator to allow more flows but redirect it away from the turbine or just use a stator that is already the way you want it and changing the angle of the pump or impeller fins is a good way to increase or decrease stall that is the most common thing to do to get a mild change the stator generally makes a major change |
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i thought i added the picture last time but here goes again
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here is a better picture of the turbine and the opposite side of the stator
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to answer your question, P.I. stands for Precision Industries www.converter.com
Ryan |
I was told that you could tell the stall speed of a TC by power braking slowly up until the tire break free and that is about 2300-2500 RPM. Is this correct for a 3000 RPM TC?
Thank you |
No thats incorrect way of checking....to many variables....road surface, tires, traction, rear brakes, suspension, etc.
One way is to use a trans-brake, another would be to drive the car and see how high the rpms flash right before the car takes off. The only problem with that is people will start to blow the tires off before getting a good reading on the tach. So most people check thier stall while on the chassis dyno if they don't have a trans-brake. From an idle they will just stand on it and see how high the rpms will climb intionally before it will "REALLY" start to excellarate the wheels on the dyno. |
I guess that would be true, too many variables. I know that when I get on it, it breaks the tire free relatively easy. Before they would barely break free and now I can be running at around 40 mph and punch it in drive and I see 2 black marks as long as I stand on it.
It's getting much better. John |
try to flash the converter to get the stall figure you are looking for
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How do you flash the TC?
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do the stall test but do it fast so the converter doesn't have time to build pressure
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Are you talking about power braking?
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yes
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What are "black marks"? Oooooh, you mean rubber.
Isnt torque braking really bad for the converter and the brakes? |
power braking just generates heat so it's not good to do alot but it is how you test the stall
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DynoJet
To me the most definitive way of checking the stall speed of a convertor is to run the car on a DynoJet. I disconnect the dentent linkage from the tranny so as to prevent down shifts. Then at 1500-2000 rpm on the rollers in 3rd gear I nail the throttle to red line.
Since the beginning rpm is below the stall speed one sees torque multiplication on the torque curve untill stall. There is a distinct point on the graph at the point of stall or coupling of the convertor. I'm going to try to attatch a dyno torque curve that illustrates what I mean. They won't let me attatch it since I did attatch it it in an earlier post. Look in the thread "REV! What did you do?" to see that DynoJet torque curve attatchment. Rev |
the fact that the tires are spinning kind of eliminates converter slippage
it seems the driver and the converter just needed a little time to get used to each other a high stall converter will definately change your driving habits i have a tighter (2800 stall) converter of the same design for sale http://forums.mustangworks.com/showt...threadid=43495 |
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