Hi guys, first off I want to say I dont have an LS1 car, but do
have some questions and need some help Dont worry,
I wont clutter up your board with non LS1 question. If the board moderators feel it
nessicary to close this post I understand. I have been reading, talking to people, following
this board for several weeks, and am trying to figure out whats what about converters.
I have a 89 T/A, I put a carbed 350 in it I will spare you the list of mods I have done to
it, but comp cams, probuilt automatics, B&M and Hughes Performance all have recomended
2600 stall for my setup. My question is what size of convertor? A local shop here in town
recomended a 12inch, B&M and Hughes recomended an 11inch. Dana at ProBuilt recomended
a 9.5. He says that the STR is around 2.5, will have better 60fts, and make my car faster
He also says that a 12 inch converter stalled to 2600 will run hotter and be less efficient.
Eveyone one else I have talked to says that this isnt the case, and that I wont be happy with a 9.5in
on the street. I see you guys running insane fast with free mods, and some minor bolt ons
and a good convertor. I know I dont need a 3500stall or anything like that, and my engine should
be putting out around 350-375hp at about 5800rpm at the crank(its a mild street car nothing crazy)
I am keeping lock up in my 700R4, but wont lock up till 4th gear(thats the way the shop set it up)
What are the draw backs to a 9.5in? I have heard excesive heat, bad driveabilty, wont stay
locked up right because of the smaller clutch, less tourqe multiplication after you get moving,
and high rpms to get the car moving. I also read on Yanks page about how enifeccient(sp?)
high stall 12in are, and how much better 9.5 are, again I know they want to sell converters.
Then I talk to people that say the same thing about the 9.5 Any thoughts on this? Maybe I dont need a 9.5 or 10in,
the car is 90% street car and will go to the track once a month or so. I just want to make sure
I get what I need, not what I think I need. I figure this would be the best place to ask, and get some good answers
I am sorry this was so long, but I am lost. I appreciate your time greatly. Jason
( I am planning on getting a LS1 though if I get the job I want) Does that count? lol

 

Welcome aboard my friend and I would go with the 9.5 I am sure there are drawbacks but there are drawbacks to everything.Yes it will be looser but it will perform better and if its not your daily driver then I would go more stall if your worried about looseness.But thats me.The 9.5 like I said though will net you better times.

 

The disadvantage to the 9.5" is that it is harder to lock-up. The smaller diameter and potenetially smaller clutch surface will allow for chatter if the line pressure is weak. The advantage is that it has less rotating mass that you are trying to accelerate. The smaller diameter is also easier to obtain efficent higher stall speeds, especially over 3000 rpm.

With a 2600 stall target on your motor (~300 RWHP, around the same power as a stock LS1) an 11" converter should be fine as would a 9". You could get a 12" to work, but you might as well reduce the mass some.

With that low a stall, you should be able to have a converter built that with a decent STR (2.2 - 2.7) and still achieve excellent efficency (96%). Whether the brands you are considering will actually deliver that, I don't know.

 

if i go with a 9.5, there is a local shop here in town. He ordered a converter kit a week or so ago and its supposed to be here soon. He said its a new kit, and he has read/heard alot of good things about it and is supposed to be versatile and he said he can make it however i want. Is the lockup chatter bad? The transmission has been rebuilt with a transgo reprogramming kit, vette servo, big boost valve, good clutches and so on. I will drive the car mainly on weekends, and some evenings when its nice, I wont be driving it everyday back and forth to work or anything like that, well I might at first just because its new <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I still want the car drivable, thats the whole reason I built the car, thats why I was wanting to know if the 9.5 would take away from that. What about having to give it more gas taking off to get it moving, would I have to give more gas with a 9.5 compared to a 11 or 12? Thanks again for everyones input. I'm all ears.

 

I wouldn't think driveability would be any problem with a 2600 stall. In fact, I don't think I would even notice it!

 

Its a kit? Does it come with interchangable pumps & stators and you pick what you want? I'd want to go with a converter that was proven to help both on the bottom end and has good efficency. I'd be a little concerned about buying a converter that wasn't asembled, welded, a spun balanced by the manufacturer.

Drivability will still be good. Yes you will use a few hundred rpms more before lock-up, but the performance gain will be worth it.

 

yes it comes with interchangable pumps and stators, the shop here in town makes conveters, he will be balancing it and putting it together. so you wouldnt think I will really even notice it?

 

ttt

 

ttt <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" />

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LilJaysTA:
<strong>yes it comes with interchangable pumps and stators, the shop here in town makes conveters, he will be balancing it and putting it together. so you wouldnt think I will really even notice it?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No I would go with at least a 3300 or so.

 

nah, i think 3300 would be to much for my setup. I know the higher the STR the less effecient it is? Does that mean that it doesnt pull as hard up top, and what do you mean with a higher STR you cant feel it stall, I read that someone on here, then he dropped it to 1.9STR and could feel it? Why? Thanks again Jason

 

The problem with mix & match parts is that I doubt you'll get the best combination of pump/stator/turbine for a given stall & STR, except by accident.

I'd pick the stall speed to be 100 - 400 rpm below max torque. If that's too high to handle, back down to a stall that you are comfortable with.

 

If its a pretty mild setup the higher stall might over shoot his peak torque which would be a no no.

We can get away with crazy stall's because our peak torque is so high and then flattens out.