will the steath ram flow enough air?

[grumpyvette]

I was asked?"will the steath ram flow enough air to make max power"

well lets do the math,

the steath ram is designed for the sbc engine, the largest normally built sbc displacement is the 434cid engine. the 434 engine spinning 7000rpm (thats well over the normall rpm for that engine even in race form) can use about 880cfm at 100% efficiency. the steath ram is cut to fit a 58-60mm twin throttle body bore size. that bore size flows about 1000cfm, well above the level thats necessary to feed even that larger than normal displacement.

now holley says that the ports in the steath ram flow about 300cfm

and several people have flowed the intake and thats true, but keep in mind that flow benches measure steady state flow, also keep in mind that the 4 cycle engine has a total of 720 degs in the total repetitive cycle and only about 250 (THE CAMS INTAKE DURRATION) of those 720 degrees are used to flow air into the cylinders on the intake stroke and if you carefully take the time to measure youll find that about 85% of that 250 degrees is flowing a usefull amount of airflow for a total of about 259cfm at a time per cycle trying to move into a single cylinder. now since the cylinder on a 434 spinning 7000rpm only needs 110 cfm even at a steady state flow into the cylinder and the cylinder can only hold that aproximate 110cfm the intake (steath ram) flows more than enough air to make max power , and more than enough air to to feed the largest flowing heads that normally fit the steathrams intake ports (like the 195cc AFR cnc heads)I was asked?"will the steath ram flow enough air to make max power"

well lets do the math,

the steath ram is designed for the sbc engine, the largest normally built sbc displacement is the 434cid engine. the 434 engine spinning 7000rpm (thats well over the normall rpm for that engine even in race form) can use about 880cfm at 100% efficiency. the steath ram is cut to fit a 58-60mm twin throttle body bore size. that bore size flows about 1000cfm, well above the level thats necessary to feed even that larger than normal displacement.

now holley says that the ports in the steath ram flow about 300cfm

and several people have flowed the intake and thats true, but keep in mind that flow benches measure steady state flow, also keep in mind that the 4 cycle engine has a total of 720 degs in the total repetitive cycle and only about 250 (THE CAMS INTAKE DURRATION) of those 720 degrees are used to flow air into the cylinders on the intake stroke and if you carefully take the time to measure youll find that about 85% of that 250 degrees is flowing a usefull amount of airflow for a total of about 259cfm at a time per cycle trying to move into a single cylinder. now since the cylinder on a 434 spinning 7000rpm only needs 110 cfm even at a steady state flow into the cylinder and the cylinder can only hold that approximate 110cfm the intake (steath ram) flows more than enough air to make max power , and more than enough air to to feed the largest flowing heads that normally fit the steathrams intake ports (like the 195cc AFR cnc heads)now as Ive said before an engines power depends a great deal on how much air/fuel mix you can stuff into, burn effectively and get out of the cylinders per second, now without power adders like nitrous or a supercharger your going to be limited to about 1.25-1.35 hp per cubic inch of displacement and the small block engine is phyisically limited in size to about 440 cid without very expensive parts. since the potential power potential can be approximately be figured with the formula (.257 x cylinderhead flow x 8=hp potential) and the best heads and intakes combined flow about 310cfm or about 625hp max potentially, the steath rams airflow falls right in at the max flow/horse power potential. most other intake systems like the TPI,super ram, performer RPM, etc. now available lack this high level of air flow when matched and flowed with the heads now available thus limiting the rate at which fuel/air mix can be drawn in, burned and expelled fron the sbc cylinders. short answer, the steath ram ,matched to a great set of cylinder heads, good roller cam and headers, makes a great combo that can come near to the max potential hp. most other intakes lower the total airflow into the engine, the steath ram being a modifyed tunnel ram intake does not and as such has the potential to make max hp in the 575-625hp range for a non-assisted sbc useing the older style 23 degree cylinderheads

[Dp351zcar]

Ok, with that said why does edelbrock make the Vic Jr? Does a single plane have better tuning for higher RPM and the tuning does not include flow volume? Should I feel stupid for getting the VicJr and not the stealth I was looking at?

358ci

10:1

Canfield 192cc

2.02/1.60

I E

.585 .550

254 262 @.050

110LC

 

Don

[grumpyvette]

the steath ram is a tunnel ram intake converted to EFI fed from a horizontal feed throttle body, because it flows ONLY air and fuel injectors add the fuel to the cylinders as a pressureized spray as the air enters the cylinder head it is designed totally differant than the vic jr which was designed as a wet flow intake with several clearance issues and a vertical flow carb. as a fuel source. your compareing apples and oranges as they say. personally I have had much better luck with the super victor intake with both carbs and when converted to EFI with injectors and a throttle body air flow control when a lower hood clearance is the goal. both the victor style and tunnel ram style intakes have thier place and make similar power but the tunnel ram intakes longer port length and slightly larger port flow #s allow a tunnel ram to make slightly higher rpm power and in some cases a wider torque band range

[Dp351zcar]

Thanks Grumpyvette for explaining that and making me realize that there is a diffrenct in wet and dry flow.

Now I really feel stupid as I did not pick up on the stealth "ram" and was thinking it was a Weiand stealth you were talking about.

 

Don

[A. G. Olphart]

Grumpyvette- Your HP calculations, links, and posts are appreciated by all of us on the board... but this one I can't follow. If each cylinder of your hypothetical SBC needs a steady state 110CFM, but is fed during only 212.5 degrees (85% of 250) of its full 720 degree cycle, would not the cfm requirement during that 212.5 degrees be found thus:(720/212.5)X110CFM=372.70CFM? Even this would seem to be an averaged figure, ignoring the reality of valve lift curves.

 

Where am I missing the boat?

[grumpyvette]

your close, but its closer to say,

the manifold is almost exactly the correct size! remember that each runner is a column of air and that air has volume, weight and energy. now its true that the cylinder can only take 110cfm BUT remember that during of all the time the engine is running is in a 720 degree repetitive cycle? and the air can only flow into the cylinder durring the 250 degrees or so that the valve is held open by the cam? well that means that the air flow needed is 720 degs/250 degrees x 110=316cfm or just about what the intake port on the stealth ram can flow at max volume. or put another way youll need to push 316cfm down the port because its only open durring 34.7% of the time available to fill that cylinder (your forgetting that at the correct tuned rpm range there is a slight possitive pressure buildup behind the intake valve due to inertia in the column of air that pressure normally reaches about 1-1.5psi durring the most effective rpm brand (lets say 1.25 psi average) so 316cfm really equals 14.7/1.25=11.76% or 316 x 111.7%= 353cfm true flow in the ram tune rpm range (thats dependent on the displacement, cam timeing, port size and rpm but nornmally falls in the 5000-7000rpm range. so yes your correct in your assesment and im impressed that you caught that!

[A. G. Olphart]

Grumpyvette- Thanks for the clarification. One assumes (love that word) that a precise answer may be found empirically with an extrude hone .

[Guest the_dj]

I don't doubt the stealth ram. I'm convinced.

 

Unfortunately I need not only the $500 intake package, but a $150 hood cowl and installation to go with it. I can't afford it or it'd already be on

 

Sam