Choosing a torque converter

[abecx]

I am looking at picking out a torque converter so I can run a bigger cam.

Most of my concerns are most likely basic bitch syndrome, but I am not afraid of asking for advice on shit I don't know about. I am looking for what questions I should be asking my builder to make sure I am making a proper decision. Also any brands/setups that would make the most sense is helpful.

I know the basics of a torque converter and how it works, to be specific I understand that the most important factor is the powerband of the car which is determined mainly by the cam.

I have a whipple charger going on a 405 hemi engine that should be in the 730-760 whp range on 91 octane. The 405 is a shortstroke engine ( 4.065 bore / 3.895 stroke ) and the whipple should cover any low end torque loss.

For what I am looking for, trying to maintain some semblance of drivability, however its being recommended that a 2800 stall is more than enough for me which I am being told from others I might not even notice the stall.

What features should I look for in purchasing one, should i find one that locks out? My car comes with a transmission cooler from the factory, is there any benefit in spending cash on some use specific fluid ( i have no idea what I would look for ).

I'm probably overthinking this, I just want to make sure I make at least a half assed informed decision.

[svauto-erotic855]

Upping the torque that the engine produces raises the stall speed of the factory converter; so does adding weight to the car or changing the rear gear to a numerically lower gear. I have had good luck with A1 converters over the years and would recommend that you give them a call.

https://www.a-1perf.com/

How big of a cam are you talking about using? What is the duration at .050 lift?

[fastwhite99gt]

If it's a Whippled car, the converter is gonna have to be pretty tight, otherwise the sudden torque spike will blow through the stall. If the cam is designed for a Whipple, then it's not going to be very big at .050 and the lobe separation is going to be pretty wide, should have pretty good low speed manners. We put a 10.5" Vigilante in a friends 2010 Camaro with a 418/4L80e combo, started as a 3200 stall with 15lbs of boost and worked pretty good, but as soon as he went to 19lbs, it went to like a 4000 stall and the combo starting blowing through the converter and the rpm would never really drop on shifts. Best bet is to get on the phone with any of the big name companies and get their tech guys on the phone.

[abecx]

can you clarify terminology, what is meant by a tight converter, and what is blow through.

I dont know the size of the cam, I originally had a 218/226 duration 0.566/0.556 cam shaft, but I was told I could make more power with a bigger cam, but I would need to get a torque converter to handle it. I am not sure why a torque converter would matter when getting a bigger cam other than getting to powerband quicker.

[Tremor14]

You just need to call one of the converter companies, and reread them your first post. The converter is something you want right the first time around.

[abecx]

can you clarify terminology, what is meant by a tight converter, and what is blow through.

A tighter converter is one that doesnt have as much slip, ergo a numerically smaller number.

blow through is the converter not able to handle the power that you're providing, tends to show in no rpm change between gears.

Let me know if my article summations are flawed. ^^^

Sounds like 2600-2800 is the best way to go which is what is being recommended to me.

[lilvega]

It cannot be an off the shelf converter. Nothing from a catalog. Must be a custom and they will need to know everything about your car including weight with you in it, tire size and gears.

[fastwhite99gt]

Dead on the money Abecx, a 9.5" converter will drive different than a 10.5" even at the same stall speed built in, simply because above the stall speed, the bigger converter will be more efficient. Blowing through the converter is basically you hit the gas, the car makes so much power that the converter can't handle it and goes way above where it was supposed to stall to and then on shifts, the rpms will stay super high. Converter setup is critical on a Whipple/Kenne Bell car, and is very dependant on boost as the torque curve is instantaneous.

[abecx]

I really appreciate the feedback. I am paying people to make these decisions for me, but I want to make sure that they are making the right recommendations ( not that I dont trust them but because I should know the basics ). So far they've made all the right ones, and this information will help me be educated when they do tell me which converter buy.

Money isn't that big of a concern to a degree, so we'll see what happens. Thanks again.

[Tremor14]

who's building the car?

[abecx]

Modern Muscle Performance is building the motor. 405 is pretty unique setup, I've been reading a lot about it. It should handle boost like a mother fucker.

BSP Motorsports is doing the installation and tuning.

https://www.modernmuscleperformance.com/

https://www.facebook.com/BspMotorsports

[DON SVO]

Modern Muscle Performance is building the motor. 405 is pretty unique setup, I've been reading a lot about it. It should handle boost like a mother fucker.

BSP Motorsports is doing the installation and tuning.

https://www.modernmuscleperformance.com/

https://www.facebook.com/BspMotorsports

Don't worry about how much boost the motor can handle, worry that the heads, cam and exhaust are optimal and that the guts can withstand the torque that blower will produce.

[abecx]

Don't worry about how much boost the motor can handle, worry that the heads, cam and exhaust are optimal and that the guts can withstand the torque that blower will produce.

I have the heads completely ported and polished the most they will go, i have ceramic coated kooks long tubes with kooks mid pipes and corsa extreme on the exhaust side. The cam is going to be custom, probably 230s 240s. I have a fuel system that can handle 1200+ rwhp. I'm not worried about it handling the boost, everything is forged, and the pistons are custom reverse domed mahles as well as coated with fucking adamantinum and carbanadium. I'm honestly not worried about anything except the drive train at this point. I even upgraded all my cooling, bigger radiator, added an oil cooler, etc...