How much rpm

[kbuskill]

You wouldn't consider the LS style, more specifically your stock truck intake manifold to be a tuned port design? I think the runners are similar in length, if not longer than those of the old school TPI. They're just routed differently for a tighter, sleeker package.

It most definitely is BUT the truck intakes runner length is 11" VS the TPI runner length of 17"... the TPI 350 was not a real high HP or high reving engine but it was very torquey.

I would be happy to exchange a couple thousand RPM up top for more power down low.

 

[kbuskill]

That's cause you're a trucker! I know, my second Buick made 200 horsepower and 300 foot pounds of torque. My intercooled ones started out with 230-245 HP and 330-345 torque. My brain has a hard time liking to see horsepower numbers exceeding torque numbers, like the LS7.

If I ever get to build a custom engine, I'll keep the 243 heads for more torque over the 823s as I increase cubic inches to at least 372.33 cid.

I know I've posted this before but I still love it...

 

[iamdub]

It most definitely is BUT the truck intakes runner length is 11" VS the TPI runner length of 17"... the TPI 350 was not a real high HP or high reving engine but it was very torquey.

Well, damn. I didn't know it was that long. I stand erected.

I suppose a fabricated long runner IM wouldn't be much work and would be a good compliment to a stroker with a proper cam.

 

[kbuskill]

Well, damn. I didn't know it was that long. I stand erected.

I suppose a fabricated long runner IM wouldn't be much work and would be a good compliment to a stroker with a proper cam.

Yeah if you count the runner length all the way into the head at the back of the intake valve you are looking at 24".

You have to remember that the intake runners on the drivers side of the manifold actually fed air to the passenger side head, and vice versa.

Plus they just looked cool... kind of like headers for your intake... lol

 

[swathdiver]

I know I've posted this before but I still love it...
View attachment 249261

YEAH!!! Love it! If we didn't brace the bodies of our Buicks, they would develop cracks near the roofline from the hard launches.

 

[iamdub]

...kind of like headers for your intake... lol

I was thinking of this last night after my last post. Buy one of those cheap DIY V8 header kits that come with a bunch of U-bends and straights, cut and squash them accordingly (to match the cathedral port), weld to some flat stock for the flanges and the other end into a plenum made from a large pipe squashed to an elliptical or oval shape, add a flange for the TB, some bungs for the injectors, vacuum ports, etc. and you'd have a relatively easy and cheap one-off long runner homemade TPI clone. I know there are more engineering factors to it other than just runner length and I'd do it more for the 'wow' factor with a design that may require a cowl induction hood. Maybe have each runner in an "S" shape- coming out of the top of the plenum, curving to the opposite side, then a 180° curve back to it's respective port. Basically, the stock design but with about twice the length. I'd coat it in a satin black heat-reflective paint to blend in and look like the stock car manifold on steroids.


Anyway, didn't mean to hijack your thread, Eric

 

[kbuskill]

I was thinking of this last night after my last post. Buy one of those cheap DIY V8 header kits that come with a bunch of U-bends and straights, cut and squash them accordingly (to match the cathedral port), weld to some flat stock for the flanges and the other end into a plenum made from a large pipe squashed to an elliptical or oval shape, add a flange for the TB, some bungs for the injectors, vacuum ports, etc. and you'd have a relatively easy and cheap one-off long runner homemade TPI clone. I know there are more engineering factors to it other than just runner length and I'd do it more for the 'wow' factor with a design that may require a cowl induction hood. Maybe have each runner in an "S" shape- coming out of the top of the plenum, curving to the opposite side, then a 180° curve back to it's respective port. Basically, the stock design but with about twice the length. I'd coat it in a satin black heat-reflective paint to blend in and look like the stock car manifold on steroids.


Anyway, didn't mean to hijack your thread, Eric

Sounds easy enough.... so when are you building me one???

 

[iamdub]

Sounds easy enough.... so when are you building me one???

As soon as I finish working on my Tahoe.

 

[STORMIN08]

i highly recommend you YOUTUBE richard holdener and start watching and documenting.

like stated, the cam with have more POWER closer to 6-6.5K rpm...but the intake with restrict it. The TORQUE will be greater as is, probably upto about 4.5K rpm.

 

[Chert_Detective]

Hey guys and gals ! I have an 09 tahoe with a stage 2 tsp custom truck cam and have gotten a custom dyno tune . I have ls7 lifters , ls6 springs , DOD delete , ls2 timing sprocket and guides . Hardened push rods and the cam is a high lift 212/218,.600/.600 ,112 LSA, 110ICL . My shift points after getting the tune are 5500 rpm . I don’t have intake or exhaust . Would I get much more power after 5500 and would it be safe ? Thank you guys . I included a picture of my dyno sheet

View attachment 249146

Looks like torque peaks about 4,500 but hp is climbing until the end. Would you get more power with an intake and exhaust? Yes. Where? That's to be determined. You need to decide where you want it.

Primary diameter and Primary length.

Large diameter = higher rpm peak torque
Smaller diameter = lower rpm peak torque
Longer length = more area under the graph before peak
Shorter length = trade your low end torque to have it not drop off as sharply after peak

As far as intake manifolds go, if you want to spend the money then yeah you have options. There are gains out there but they are not much more than the factory truck intake so spend your money wisely. I'm running a FAST lsxhr along with other stuff. But it's almost 14" from the start of the velocity stack to the back of the valve. Being a cathedral head on the 5.3 you won't be able to use that one but you could still run a Holley Hi-Ram or other long runner manifold. As mentioned though, the gains over the stock manifold may not be much since most of the increase will be from the larger plenum volume over the stock intake, not so much the change in runners.