Stock lm7 turbo build

[Drunkcanuk]

Would a say 4.11 be that much of a difference for say a 0-60 time?

Absolutely.....the lower the gear, the quicker you get going.

 

[RDF1]

Would a say 4.11 be that much of a difference for say a 0-60 time?

It depends on the setup really. Ive never done 0-60 times but for drag racing and looking at 60' times along with 330' times ive had best luck with 3.42s and 28-29" tire with turbo trucks. But the torque converter has to be spot on.
I use Circle D for turbo trucks with 4L80s.
Ive got a couple customers with regular cab 2wd trucks that have gone 9.7s in the 1/4 mile with just a cam only 6.0, 82mm turbo, 4L80, Circle D 258mm Pro series converter, 3.42s and 29" drag radials.
I wouldn't run a 4.11 in a turbo truck unless it was a crew cab 4wd or something heavy.

 

[618 Syndicate]

Absolutely.....the lower the gear, the quicker you get going.

Higher numerical gears are an equalizer (or bandaid depending on how you're looking at it) for less power.
This is especially true on a street vehicle.

 

[Drunkcanuk]

Higher numerical gears are an equalizer (or bandaid depending on how you're looking at it) for less power.
This is especially true on a street vehicle.

This is very true. With a low HP vehicle, it will make it seem faster.

But since the OP is talking turbos, he should have more than enough HP to get going fast enough with higher gears as suggested by @RDF1 and enjoy lower rpms at cruising/highway speed.

 

[RDF1]

I agree @Drunkcanuk. Since the turbo setup will make more torque, use the higher gears to stay in the torque range longer and acceleration is improved.

I tuned a kids 04 RCSB truck with a chineseium 80mm 6.0, 4l80, converter, 4.56s, and 30" slicks. At 130mph he was at 7000 rpms. It felt really quick cause it was shifting gears really soon. But he got out run by some my other customers turbo trucks

Talked him into letting me put some 3.42s in and retune it.
Now he is the faster one haha. Converter is a tad more loose now from the higher gear and now he can run 130mph and still be in the peak torque so it never stops pulling.
Unfortunately i didnt have my Draggy for a back to back comparison but the data log shows almost a 1 second difference on the 0-130mph pulls. Also the 3.42 gears allowed it to build boost a little earlier from the extra load. And he picked up 3mpg.

Building him a 370ci now and going with a 83mm turbo, also swapping it over to to a Holley ECU.

 

[Romanheystek]

okay and how do torque converters work and is a expensive one really needed.

 

[Sean Buick 76]

When making lots of power the. Yes a high end converter is a really good idea. They multiply the torque and can help launch the vehicle off the line. A low cost converter can really slow down a combo and lead to a trans failure. A low high high stall converter will cause excessive heat and loss of power from wasted slip. I’ve paid $700-$1400 for good converters.

 

[Romanheystek]

When making lots of power the. Yes a high end converter is a really good idea. They multiply the torque and can help launch the vehicle off the line. A low cost converter can really slow down a combo and lead to a trans failure. A low high high stall converter will cause excessive heat and loss of power from wasted slip. I’ve paid $700-$1400 for good converters.

Okay makes sense thank you

 

[Romanheystek]

Looking at a lm7 tomorrow with 100,000 miles and it’s $400. Comes with everything including all of the accessory drive.

Is it a good idea or should I stick to the lq’s?

 

[Sean Buick 76]

Looking at a lm7 tomorrow with 100,000 miles and it’s $400. Comes with everything including all of the accessory drive.

Is it a good idea or should I stick to the lq’s?

Nothing wrong with a 5.3 for boost. It’s pretty easy to meet most people’s goals with one. I prefer the 6.0 simply because it allows better torque before the turbo hits. That being said if you use the right turbo for the combo there are no issues with lag.