97 Cobra LSx Build Thread

[Sam88gta1]

You should either keep the 4.10 gear or find a 5.3 motor. That 4.8 will be dead below 5k rpm no matter how much boost you put to it.

[Cobraman]

You should either keep the 4.10 gear or find a 5.3 motor. That 4.8 will be dead below 5k rpm no matter how much boost you put to it.

should be ok. Truck cam/intake, small fast spooling turbo. It isn't a Gen 3 motor

[Sam88gta1]

should be ok. Truck cam/intake, small fast spooling turbo. It isn't a Gen 3 motor

How much power do you expect to make with that combo?

[Cobraman]

How much power do you expect to make with that combo?

low 500's on 12-15 lbs.

[OreoStang]

U still plan on using the on3 kit? is it a turbo u need or the whole kit?

[dville_gt]

I just did a 4.8 liter truck (stock everything but turbo/fuel system) with a on3 76mm and like Sam said, it is a dog at anything below 4500. Would be a lot better if it was an auto with a big stall, but since it is a manual it really isn't much fun to drive. Made 210rw stock and 430rw on 12lbs.

[Cobraman]

Hmm. This motor should make 250- 280rw. I think a quick spoolin 70mm should be just fine. It can't be worse than my 4v Centri. Not to mention my car is a few thousand pounds lighter and has gears.

[Baron Von Crowder]

I just did a 4.8 liter truck (stock everything but turbo/fuel system) with a on3 76mm and like Sam said, it is a dog at anything below 4500. Would be a lot better if it was an auto with a big stall, but since it is a manual it really isn't much fun to drive. Made 210rw stock and 430rw on 12lbs.

I get calls from people looking for a 4.8, and they want them for some reason, and will pay more for them than a 5.3. Never made sense to me.

[shumpertdavid]

I get calls from people looking for a 4.8, and they want them for some reason, and will pay more for them than a 5.3. Never made sense to me.

Cobraman, sell 4.8, pocket extra change, install 5.3, or add boot and do 6.0.

[VaderTT]

Being light and having low gears (numerically high), not the best for putting load on that turbo. Does depend on gearing, stall, tire height and such though.

[Cobraman]

Cobraman, sell 4.8, pocket extra change, install 5.3, or add boot and do 6.0.

I'm not worried about it. The gen4 4.8 has a very similar dyno to the gen3 5.3. They make the exact same peak numbers, and low end is similar. it's going to be fine. It's a DD after all.

Being light and having low gears (numerically high), not the best for putting load on that turbo. Does depend on gearing, stall, tire height and such though.

It will probably get 3.73's. I'll see how it runs and start making changes.

[VaderTT]

I'm not worried about it. The gen4 4.8 has a very similar dyno to the gen3 5.3. They make the exact same peak numbers, and low end is similar. it's going to be fine. It's a DD after all.



It will probably get 3.73's. I'll see how it runs and start making changes.

How tall is the tire? I would try 3.31 or 3.27.

[Cobraman]

How tall is the tire? I would try 3.31 or 3.27.

It doesn't have tires

[CRASH]

LOL, don't listen to Sam or James.

They probably don't know what they're taking about.

They only work on & tune these engines every day.

[Cobraman]

LOL, don't listen to Sam or James.

They probably don't know what they're taking about.

They only work on & tune these engines every day.

apples to oranges. Dvilles talking about a 4800lb truck with a gen 3 4.8 that made 210rw stock. probably with 3.08 gears.

I'm talking about a 3100lb car with a gen 4 that makes 50 more horsepower stock with more gear. It is going to do better. Like I said, my centri 4v was pretty quick and it didn't make any boost until redline. I'm not looking for a drag car. If it were so bad there woudn't be hundreds of 4.8 builds.