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Torque Converter Question?


Guest zfan

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I recently installed a 700r4 in my 240Z. It is a vette tranny with the stock converter. Im currently running the Edlebrock rpm package. The cam is decent, duration is at .006, 308 int, 318 exh. cam lift is325/340. valve lift is 488/510. My problem is at idle in neutral is 1100 rpm's, in gear it drops to 500 to 550 rpm's.

 

The shops I've talked to say I need a 2400 to 3000 rpm stall converter such as street fighter, saturday night special, etc..

 

Has anyone gone this route or had the same problem? They say my performance will increase greatly with this mod. I do not want to waste money when I can put it to good use somewhere else.

 

One shop that has done work on my Z and is not a tranny shop but has a very good rep as an engine builder etc. and has nothing to gain also says go for it you will not regret it.

 

Ok guys what do you think? Fire away please.

zfan..Mike icon_rolleyes.gif

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Guest Anonymous

With that 'RPM' setup power probably starts real strongly at 2500 rpms. The Z is light, the rear end gears are usually 3.54 or higher numerically which means it'll RPM really quickly. I would probably get a looser converter, but I personally wouldn't go with a super high stall speed. I'd probably use the Holeshot 2000 maybe the Holeshot 2400. My reasoning would be to go with the tighest stall you can that will still allow decent idle yet slip enough to get into the Horsepower of the motor.

The bad things about to much stall is it takes alot more throttle to get moving which is a PITA on just cruising and definately gas mileage will be lost The extra slipperage will definately heat things up, so you may want to consider a trans cooler as well if you havn't already.

 

My .02,

 

Lone

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Guest Night_rider_383

I would have to go along with lonehdrider

on this. I can tell you for a fact unless its a race only car you so don't need nor want even a 2800 stall much less a 3000 stall in a car that light. The higher stall speeds lets the converter slip more down low to build rpm faster. This also will cause a loss of movement per rpm when your just cruzin around or go up any kinda hill. It will kill some mpg. We lost 2.4 mpg when we put a 2800 stall converter on our chevy c/10 p/u. went from 12.4 to 10 mpg, and when your going up a hill it kinda feels like the trans is slipping. This is the loss of movement i was talking about. If your rpm drops that low when you hit gear then yeah you do need a higher stall speed but look into something around 1800-2200 rpm. You be happier with the lowest stall you can get in there that keeps your rpm from dropping if its a streeter.

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Well broke down and purchased a B&M 2300 stall converter, called holeshot I believe. They are 50% more expensive for the 700r4's than normal turbo 350 converters...yikes.

 

Decided to have shop install as they will also get tranny set right included in price.

 

180. for install and tune and 335. for converter. Dang cars aint cheap! icon_eek.gificon_mad.gif Mike

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Guest kc6wfs

Hi Mike,

Congrats on the converter.

Will you still be able to use the lockup?

I also run a 700R4, have not yet hooked up the lockup wiring yet, but going to go a higher stall converter soon.

 

Ya the prices are steep. Someone said you could use a nonlockup converter it's cheeper but you would loose the lockup. Probably not a good idea unless it's never on the freeway.

 

Let me know how it is after you install it.

 

Dave

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Guest Anonymous

I think you'll be pretty pleased with that setup. They are definitely expensive, I remember when I researched the automatic I was shocked at the price diff between the T350/400 and the 700/r-4 converters. I'm sure they're more involved than the earlier converters but damn... icon_smile.gif

 

Regards,

 

Lone

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Mike,

I probably should have replied earlier, but I haven't been keeping up on the forum lately (bad me!!!)

 

Anyway,

I've got a 3000 stall B&M converter in my 700R4. I love it! It completely changed the way the car feels. One myth about torque converters is that the car wont budge until stall speed is reached. This is not true. Even at my 1000 rpm idle, the car will still eventually creep forward. However, the more load I put on the motor, the more the converter will stall. Taking off from a stoplight under modest footing, the converter will stall at about 1800 rpm. In fact, it's very difficult to get the full stall out of these converters in a Z car. Only when I run my slicks will I ever see 3000 rpm stall. Even then, it only last's for about 1 millisecond icon_biggrin.gif

 

One thing I highly recommend is making the lockup work. Not sure if the "Holeshot" has lock up ability or not... it seems B&M only does it on about 1/2 of their 700R4 converters. If it does have it, try to get that hooked up. It's very easy to wire up(plenty of discussions hidden deep in the archives) and it will redeem all gas milage loss due to the higher stall.

 

$180 sounds pretty good for a trans install. $335, on the other hand, sounds about right for 700 converters. Kind of maddening when the exact same converter for the TH350 is less than a hundred bucks! Oh well, it's the price we all have to pay... well if we want automatic overdrive at least icon_rolleyes.gif

 

I think you will be very happy with your choice.

 

-Andy

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Andrew,

 

What about additional heat; remember-you're in Michigan & ZFan is in Dallas; our Summers last a little longer than yours.

 

Have you ran your car during the hotter days of your Summers; what was the heat build up-was it noticeable? I would definately want a Trans Cooler!

 

Kevin,

(Yea,Still an Inliner)

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Kevin,

It can just as hot up here. In fact, It's something like 92 degrees right now. Since the Z is primarily a summer-only vehicle, it's seen it's fair share of +90 degree days in rush hour traffic. I've never had any problems at on the street, or at the track on these hot days. I've installed a trans-cooler as a safety means, but even beofre the cooler I never had any trans overheating problems. The biggest thing that is heating up my trans right now is actually the exhaust. I get a lot of heat built up in the trans tunnel from the exhaust. I'm wondering how much of that is getting transferred into the actual transmission. Who knows...

 

-Andy

 

P.S. Kevin, when are you coming up here to make good on that "water ski with a 150' rope" promise I made? icon_biggrin.gif Summer only lasts a few weeks up here.

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