Low Boost 416 Single Turbo Selection
 

Hey guys I’m building a 77 C10 and I’ve got a 416 short block with LS3 heads that I was originally planning on slapping a TVS2300 onto but my brother is enjoying the blower so I want to do another turbo build. I only plan to make 650-700whp on E85 so it won't take much on a 416. I’d like to use a KB or Trick T4 manifold and I’d actually also like to use my blower cam as well with the following specs. Any thoughts? Not going for forum winning dyno numbers just a tire spinning street truck. Most will think my numbers are sorry for a 416 but I’m fine with that.

227/243, .612/595, 117 LSA

S484/96 1.25 T4 would probably do you fine. The 84 billet wheel works as it has a very broad compressor map at higher airflow rates at lower pressure ratios (where larger 4" stroke based engines will operate in a street driven application).

The cam is eh.. assuming it's a 117+5, the 63.5 exhaust valve opening is close to what I'd aim for a 416 street driven vehicle... probably around 61-62 degrees. Intake close will be a little earlier than I'd like with the 4" stroke, but it could work. Add 10 degrees of duration on the intake and it'd be a pretty good cam for that motor/turbo.

Thanks Jake. Based on that theory of adding duration on the intake, it should mean that the motor will make peak power at x rpm lower than it "should" correct? So with a 237/243 it would make peak at say 6200rpm, but with the existing cam it might peak at 3-500rpm lower?

Here's the cam card:
https://cimg0.ibsrv.net/gimg/ls1tech...95975d9c57.jpg

I would still be using a T6 turbo and manifolds on 416 cubes even at low boost.

S480 T6 1.10 would be smallest I would go. on 416 cubes it will make your desired power at around 10PSI with no back pressure and nothing working hard. also leaves plenty of room to turn it up

Richard Holdener tested an S480 T6 1.10 and T4 1.25 and they were the same on a 370 in terms of backpressure. So.

do you have a link to the data? i'd be curious to see....

I wonder at what boost it was tested?

without personally having done it I assume cubes will have a massive influence in terms of packpressure

The numbers on your cam card don't add up exactly right, unless the cam duration is actually a few degrees different than you say, however, I think your cam will be fine. Be sure to degree it as best you can. It will for sure peak early, but its going into a truck. So it will be just fine.
for turbo selection, I think the Bog Warner S475/96, or S480/96 will work very well, and those are the best bang for the buck quality turbos available, but you will have to spend money on a T4 turbine housing to make it fit nice on that KB manifold you want to use( 1.1a/r, or 1.25a/r would be good)

Don't over turbo it for such lowly goals. Any reasonably sized turbo will make that power at low boost. If you're honest with yourself that 650 doesn't become 850, go smaller on the turbo and increase your area under the curve power. I also didn't see a max rpm which will also play into the turbo choice.

I agree

Finally somebody gets it. You could hit his power goals N/A. The only reason for a turbo is to make the same power with a much more streetable combo. A smaller turbo is also easier to package. A 416 could do 650 while being smooth as glass at idle and very quiet overall. The only issue would be managing all that low rpm torque.

I usually get hated on for "undersizing" the turbo or cam on here.....then the OP goes with my suggestion and comes back to thank me and it's crickets on here. :jest:

I agree about not going wild with stuff,
And the OP can most definitely make use of his existing cam, and an S475/96 or s480/96.
416 ci will be very happy with those parts, even at a low boost to make 650whp. Which will likely be about 8psi, maybe less

Lots of good info here guys! Will likely be going with a S480/96 T6 and keeping the cam I already have.

A 416 could do 1000 and have a smooth as glass idle and be very quiet.


The joys of boost.

Since I started DDing an electric Leaf, my concept of smooth and quiet has been a bit skewed. My Mercedes E seems loud by comparison. When I finish redoing the GTO I may need earmuffs just to look at it, LOL.

Aint no 1000 anything in a Leaf though !! Not even 100...miles !! lol

Call me a pussy, but I'm only building the GTO for about 700. The drivetrain upgrades become too compromised above that. One of the compromises being able to still afford food, lol.

I hear ya !. But I still couldnt drop to a Leaf myself lol.

But electric really does have some appeal for a daily, even more so if charge points are free which would mean almost free motoring.