Torque Converter Validation

[scoti]

I do understand the gear change will give me much better "off the line" pick up and that is in the plans however, What about blueprint calling for a converter in the 2,000 - 2,400 range? I gotta do one project at a time and right now it's engine swap. Gear swap can be a project coming up soon. I actually do mind the freeway gears.

The converter makes a difference for sure. Stock converter is </= 1400-1800. 4.3 Vortec converters are a little higher 1600-2000.

No, a stock unit won't be optimum but one will do & is close enough to their 'recommendation' for now since it's a street car. Tell Blueprint you'll be running 2.28 gears & a 26" tall tire & I bet they'll be telling you to change things. I would opt for the v6/4.3 converter. Us poor boys commonly did that back in the day. Heck, I told my buddy (he works for GM) to search for a 'modern' version to go w/his 5.3/Stage2 truck cam LS swap into my old '90obs Chevy & to ask his guy that built the trans what he recommended. He said the 6cyl Vortec converter was still a good low budget choice.

Race car doing race car stuff? You definitely want to get the converter as close as possible to the engines needs. You'll also have the gearing already in place to work w/the combo.

*EDIT* OD/4spd trans changes the game & needs.

 

[spidereyes455]

Another cheap hack back in the day for a non lock up th350 was to order a converter for a chevy vega since they had a 2800 stall speed.

 

[64nailhead]

You're intended use of the car is needed. I'll assume you don't intend to be at the track much with that gear ratio. If you never intend to launch this thing hard, then 2400 is fine.

What's the torque curve look like on this motor?


melloelky is spot on. It's very common for everyone to put in too small of a converter. That's a healthy cam and I have ti believe that your motor is not going to be happy on the highway 1800-2000 rpm's. Determining cruising rpm for a non lockup is pretty important.


A couple of things stand out, 1st, you know you have to change the ratio at some point. That means that if your converter works good with this gear set, then it won't with 3.__ and OD. 2nd, 2.29!!!! Fargin' yikes - do you highway drive at 85 alot? 3rd, budget converters are just that - budget, and there is not anything wrong with that. But when the time comes get a proper converter to make your combination really shine.


For the time being, grab the converter you listed and throw it in there - it will work much better than a stock converter. But when you upgrade the trans and rear, be advised that the whole combo will be good or bad based on the converter. The wrong converter can make for extreme disappointment and the right one will feel like you added 200 ponies.

 

[scoti]

You're intended use of the car is needed. I'll assume you don't intend to be at the track much with that gear ratio. If you never intend to launch this thing hard, then 2400 is fine.

What's the torque curve look like on this motor?


melloelky is spot on. It's very common for everyone to put in too small of a converter. That's a healthy cam and I have ti believe that your motor is not going to be happy on the highway 1800-2000 rpm's. Determining cruising rpm for a non lockup is pretty important.


A couple of things stand out, 1st, you know you have to change the ratio at some point. That means that if your converter works good with this gear set, then it won't with 3.__ and OD. 2nd, 2.29!!!! Fargin' yikes - do you highway drive at 85 alot? 3rd, budget converters are just that - budget, and there is not anything wrong with that. But when the time comes get a proper converter to make your combination really shine.


For the time being, grab the converter you listed and throw it in there - it will work much better than a stock converter. But when you upgrade the trans and rear, be advised that the whole combo will be good or bad based on the converter. The wrong converter can make for extreme disappointment and the right one will feel like you added 200 ponies.

So, in this situation you're saying a TH350 w/a 2400/2.29/26" combo will yield better results vs a stock stall/3.42/26" combo?

 

[64nailhead]

So, in this situation you're saying a TH350 w/a 2400/2.29/26" combo will yield better results vs a stock stall/3.42/26" combo?

No. He's saying that he's not swapping the rear for now. So I'm saying a 2400 stall will be better than a stock converter with that gear. If the rear end swap isn't in his cards for the moment, then he needs something other than stock converter stalling at 17-1800 rpm's..

I understand completely about not wasting money on a temporary setup. Get something that works and drive the car - adjust from there. Nothing is going to work well with his current gear ratio, but a converter can help crutch the issue until he has the funds to upgrade. And if he needs a converter anyway, then the budget B&M will be be better and get him by until.....


Quick story (sort of), my son drove my car after it was initially setup. I grabbed a stock reman converter from Advance Auto for $175ish just to get the car moving. He told me that it took over 3 seconds to build boost from 60mph. I explained it was because of the converter but he was shaking head at me and said something along the line of - this is a total POS and almost undriveable. I chuckled and told him I'd be ordering something once the bugs were out of it. And I'll agree that it was absolutely, 100% pathetic to drive - 4.8, SS2 cam, 3.73 gear, 26" tire, 4l80 with an S475 T6 (900 HP capable) turbo.

Just sayin' 🤔