Yeah, the STR really isn't a set in stone thing. If you do mostly street racing i'd get like a 3600-3800 with a 2.0-2.1 STR. Now if it's track racing i'd get something in the 3800-4200 range with a 2.4-2.6 STR. The lower STR will be a little looser, but you will gain some effiency for roll racing on the street.

 

How much more efficiency will i get with a 2.1 vs a 2.4 and what exactly is "efficiency". Right now, i think iwould want to order the 4k 2.4 str. Im full bolt ons ONLY with BFG drags around town and need the fastest verter i can get and keep it reasonable.

 

Efficiency is basically how much energy (or horsepower in our case) the converter "wastes" to heat/slippage/friction, etc. It's the same concept why an M6 car traps high and is (generally) faster from a roll. M6 doesn't have a big torque converter slipping and giving off in the form of heat/slippage. So you're basically looking at a sliding scale.... Here's a good way to view it:

A converter that's a perfect match for slicks (higher STR, higher stall) will be the fastest on the track, but you will trap lower, and thus lose a little bit of oomph from a roll on the street.

A converter that's perfect for drag radials (not as much STR) will not be quite as fast on the track, but you will retain a little more trap speed in general (but the car on slicks will murder you on the 60ft and thus beat you in the quarter).

So the result is, when you take the "slicks" car (high stall/high STR) on to the street and slap on drag radials, you CAN feather the pedal and launch just as well you could on drag radials, but the lower STR car will still probably win 2 out of 3 on the street, because it will launch more consistently, and lay down a few more ponies to the ground. Obviously this is assuming all other factors are equal (driver, mods, etc, etc). I'm talking strictly the result of swapping converters with everything else constant.

Is it going to be a noticeable loss of hp to the wheels? No, not really, but it may be just enough to pull 1 car on the M6 guy next to you that has an LS6 intake when you dont. Anyway, they key points are: You will have an easier time launching on drag radials on the street with the lower STR and you will be retain more power from a roll. You will be faster on slicks with a high STR. With too much STR on drag radials, you will have fun, but your car won't be as quick (until you put on slicks).

3.23's aren't overly aggressive, so you can probably get away with a moderate STR, especially on the BFG's. It's a different story when you go to 3.73's and have a high stall/high STR. Even on drag radials, the car will be a handful with that type of setup (again you can always just feather it, but you're giving up some top end power for STR that you can't make use of, due to tire limitations).

 

great info there thanx

 

Yea im keeping stock rear gears, wont be swapping those out. Car wont see track much so i basically want the fastest set up for my on the street with BFG's and 3.23's. Your write up was very helpful, bTW, thanks a lot!

 

Yep, for your purposes, it sounds like you don't want to go too high with it then. Like I said, you can always feather the throttle back, but then you're just giving up some efficiency for no reason, and you'll just waste all the STR with tirespin, and make your car less consistent. The 2.73 cars usually see GREAT times with the enormous converters, because they make up for the milder gearing w/ the really aggressive converters. 3.23 or 3.42 is a great gear for the street though, so I think you'll be happy with the 3.23 gearing once you get the verter in there. People like XTrooper I believe, have actually gone *down* in STR/stall and improved their times, too, so don't freak out too much about regretting the decision later. There's a wide range of converters that will have no problem netting you .5 in ET. It's kind of like choosing a cam, gotta take all the factors into consideration and pick something that suits your needs. Sounds like you're on the right track though!

 

Yea, maybe a 3600 2.2 str would be best for me? i dunno, keep the opinions flowing

 

3600 is pretty good for a daily. Do you ever plan on a cam swap?

Also, have you called Fuddle racing and talked to them?

 

3600 2.2 sounds like a very good decision for your needs. Some people will change that up based on how they like the car to "feel", some people like the converter to feel looser and lazier (sitting still at a stoplight with no feet on the pedals, while in gear, etc, kind of a torquey *slingshot* feeling under acceleration), some people prefer it "tighter" (snappier throttle response, closer to how a stick feels, less throttle required to move the car). This of course would be determined by stall speed. Higher is looser, lower feels "tighter".

 

ive got a 3600 now, sometimes i wish it was lower, more like stock

Fuddle said with my plans i should go with a 3800, so i feel i got a nice compromise

 

I am also keeping the stock 3.23 gears. My car is a driver and i'd like to get the most out of it that I can, which means to make it faster and more fun to drive without going crazy and killing my mileage. With N20 you can make a 10 second LS1 and still retain factory mileage...

So 3.23 + Yank SS3800 2.5 + Drag Radials is the combo i'll have.

 

3800-4000 2.1 should be perfect

 

Ok, so maybe a higher stall speed but lower STR? That way i get the torquey feeling and the RPMs will jump higher from a hit correct? But with the lower STR like 2.1 i will save some traction and be more efficient. I have talked to Fuddle but it has been about other needs/wants, etc. I am not going to bug him again until i ready to order, which will be when i get $500 more. haha

 

Yep, you got it!

In fact, at the moment you leave the line, a higher stall will have your engine producing more torque. So if you had a 2500 stall/2.5str, versus a 3800stall/2.1str, it's likely that the 3800 will actually lay down MORE torque as you leave the line, while still being MORE efficient on top end! The only downside (if you view it as a downside) is the looser feel which some people don't like. So if you really want to be 100% positive, just ride in, or drive, a car with a fairly high stall and see if it bugs you. To some it feels like the engine and the car are "disconnected" more than they'd like, which is why you hear complaints about feeling "too loose", but anything below 4000, I don't think you'd really be too bothered by it.

 

Yea, i doubt looseness will bother me, i dont mind. Im definately thinking a higher stall with lower STR. thanks for your help. any more input to screw with my head and make me change my mind again?

 

i voted for a 4000, i have a 4000 with a 2.5 str, and its a beast on the street, but very drivable, its all in how you tune it. I have mine tuned to lockup at 40 mph which lets me get great gas milage, but when i need the extra push i hit it and it flashes to about 4250 rpm and pnding traction the cars runs like a raped ape. I used to have a 3500 stall but im glad i ditched it for the 4000

 

What tires do you run and how do you usually go about to find traction on the street? Like do you have to feather into it or like lets say you hit it from a 40 roll, do you get traction?

 

I got a 4400 on a 2.9 STR
Don't go so big on an STR for a reguarly driven car, unless you have a couple hundred sets of extra street tires

 

Here is an idea for you Superman: Get a big stall/str that you can lock at WOT. Best of both worlds. You get the benefit of the big verter to get you up to speed, then lock it for the efficiency of a manual.
Since you have to save up anyway, maybe wait and see what Fuddle's Ultimate Street converter is all about.

 

Alright, ill check that out. Im thinking maybe a higher stall like 3800 but a lower STR to keep traction a little easier and a little moreefficient but ill still have the 3800 stall to jump the RPMs up and get me going. Whats the scoop so far on their new verters?