5.8 Swap in the works, questions.

[hemihotrod402]

Update: Got my lightning EGR..just need to trade the mine with the 70mm that Scott Has That will be one thing off my list.

[hemihotrod402]

Bringing this back lol.

Granted I haven't been able to measure the TFS intake (this build has been put on hold for a while. but I am getting a few parts), but if for some reason it doesn't fit under the stock hood, would there be enough clearance between the cross member and the oil pan to fab up some motor mounts that would drop the engine, say an inch?

[sly]

if you used solid mounts. Not sure that rubber mounts would be able to keep the engine from tapping the cross member. I think there's only just over an inch of clearance at the oil pan to begin with.

[jayh]

I havent read this in a while.

a tfs351 intake and a gt40/lightning are alot different. you might want to consider edelbrock or proproducts if the tfs doesnt work out

xe258 is gonna be dinky in a 351; with that combo, if want a comp cam, you probably want an xe270 on a 114

[packman]

I've been interested in Lunati 55123LUN. I'm still curious about the TFS stage 1 cam as well. There was a Comp Cams grind in one of my catalogs that I was looking at, but I can't find the issue. It might be the one that JayH suggested.


Packman

[Mercracer]

8 psi is for kids. With a good bottom end, you'll be good for twice that.

You do realize that boost is merely resistence to flow....right? Boost alone is not a valid measure of power increase. You can make stupid power with 8psi of boost. 8psi can give you a 40% or higher gain in horsepower with a properly tuned system.
A 302 with P heads is capable of pushing a CV into the 12s with 8psi of boost. Not exactly just for kids...

[packman]

I found the cam I was looking at in the Mustangs Unlimited catalog. It's Comp Cams XR270RF-HR like jayh said. I do like the specs for this cam.


Packman

[hemihotrod402]

What's the part number on the XR270?

EDIT: Nevermind found it on camquest

EDIT AGAIN: I found it on Comp's Website:

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=895&sb=2

It says not for motors that came with a hydraulic roller, and not for EFI. If I do a 95 F150 Block running EFI, wouldn't that eliminate that? Or am I missing somthing?

[jayh]

that is a retrofit/reduced base circle cam, not the one you want

its this cam-

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1060&sb=2

but there is or at least was 2 versions, a 112 and a 114, the 114 might suit you better

I would look for this used, new price, you can go custom for another $22

[hemihotrod402]

that is a retrofit/reduced base circle cam, not the one you want

its this cam-

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1060&sb=2

but there is or at least was 2 versions, a 112 and a 114, the 114 might suit you better

I would look for this used, new price, you can go custom for another $22

ahh thank you sir

[P72Ford]

You do realize that boost is merely resistence to flow....right? Boost alone is not a valid measure of power increase. You can make stupid power with 8psi of boost.

Right. And I will get to that in a second. But by using "child's play" I did not intend it to mean that 8 psi is trivial. My intent was to convey that 8 psi is not a tall order for a built bottom end, especially when certain stock factory shortblocks can see 15 psi.

Measured boost pressure is actually quite worthless in determining the improved power output without supporting information. Pressure gradient means very little in regards to how much air you are actually moving if you don't also know things like the volumetric flow rate (and/ or mass flow rate and fluid density), the geometry of the cross section you are flowing through, state of the fluid you are moving, and a possible host of other attributes. While these are text book terms, they apply to the conversation in the respect that if you know about the engine's capabilities regarding camshaft, cylinder head, intake, etc selection, you will have a better idea of what 8 psi will do for you.

On a stock engine, 8 psi may net you a 25% increase in power. With better heads, proper cam selection, etc, you may see a 35%+ gain simply due to the fact that the engine is capable of "using" alot more volume of air at 8 psi than a stock engine.

There many, many variables to consider to make a totally accurate conjecture regarding the power you will make at a given boost.

I think alot of times, though, tossing out a boost value gives folks a general idea of whats going on, if they know some other basic details of your set-up. Its kind of like using horespower as a way to estimate a car's performance. The number's really aren't that useful without supporting information regarding the vehicle.

Depending on who you talk to, I may or may not have a decent understanding of fluid mechanics.

8psi can give you a 40% or higher gain in horsepower with a properly tuned system.
A 302 with P heads is capable of pushing a CV into the 12s with 8psi of boost. Not exactly just for kids...

If 12-13 non-intercooled psi can put my truck in the 13s, then 8 psi can put a panther in the 12s. My truck weighs 5000 pounds with me in it, has an otherwise stock 287, 4x4, 3.55s on 32" tires, and has a 5 speed manual transmission (making it a little harder to stay in the boost).

[jayh]

no generally 8#'s will give you a 40% gain. it is a generic formula, but its ball park
a pulley configuration that makes 8psi on a 225hp HO might only make 6psi on a 350hp combo
but ballpark 8#'s on a 225hp motor will make 315hp; 8psi on a 350hp motor(h/c/i) will make approximately 490hp

but boost is just back pressure; efficiency of the compressor, heat of the charge, and the ability of the motor to move air on its own, are all factors

[P72Ford]

no generally 8#'s will give you a 40% gain. it is a generic formula, but its ball park
a pulley configuration that makes 8psi on a 225hp HO might only make 6psi on a 350hp combo
but ballpark 8#'s on a 225hp motor will make 315hp; 8psi on a 350hp motor(h/c/i) will make approximately 490hp

You can use whatever numbers you want. 25 and 35 were chosen for the sake of discussion. 40% might be the case for engines that you are familiar.

And I believe I mentioned the fact that with better components, the engine will "use" more air, which means the blower will not be able to compress the air to the same pressure, thus a lower boost value.

[gadget73]

And I believe I mentioned the fact that with better components, the engine will "use" more air, which means the blower will not be able to compress the air to the same pressure, thus a lower boost value.

if I understand this correctly, its basically moving X volume of air through a pipe of Y size. Decrease the size of the pipe (more restrictive engine), and the pressure goes up assuming the same volume. Conversely, increase the size of the pipe (improve the engine's airflow characteristics) and the pressure goes down for the same volume of air, yes?

[1980c10]

You got it.

Ninja edit : Speaking of psi lol. One of my buddies has a cummins pulling truck. Its a first gen body with a 12 valve from a second gen. With compound turbo's. Completely built top to bottom. He revs it to 6,000 rpm when he is pulling. Anyway we had it on the dyno about a month ago, only made the runs to 5,000rpm instead of 6K, It mad 595rwhp and 1,000+ ftlbs IDK how much over the dyno only went to 1,000. The reason for the story he was making 95 lbs of boost on the dyno. He has a 100 lb gauge and he said he maxes it out when he is pulling lol.

Sorry for the OT but I figured I would share lol.