Standard injectors and manifold

[ab56452001]

Hi again, as i previously stated in another thread im really happy atm with my latest buy, Vr Stato 5.0l with auto, alot of work done by previous owner to make it run and sound that little bit sweeter !. Here go's, heads bowl job and decked,crane 276 cam with lifters and springs , rods resized and Arp bolts,block chemicaly cleaned tested and 30th hone/bore,Pacie's in to twin system, uprated harmonic ballencer and oil pump, upgraded leads and plugs , all put together then chiped and dynoed to match cam and stallie (rebuilt box with 2200rpm stall and chev servo piston), plus a bit more i forgot !. my question is , for how much flywheel horsepower are the standard intake manifold and injectors good for ?, as for as i know these are stock.

 

[Munz]

The banana's manifold can be swapped out when the car is stock and horsepower can be made as its that restrictive. Also if you plan on swapping it to something better I would be using either Group A injectors or blue tops although the blues could be slightly over the top for the power.

How much power is the car making?

 

[Aussie V8]

The standard manifold flows something like 500 cfm. It is quite restrictive but good for torque production. There is a mathematical formula for figuring HP potential but you need to be able to "guess" accurately the Volumetric efficiency of the engine. When push comes to shove you can have the bells and whistles in the old EFI V8 but without some work the manifold will restrict overall output even with an engine running over 100% Volumetric Efficiency.

 

[ab56452001]

Thanks for replies, i havent checked compression yet, i suppose decking would have added a bit, and im not sure about the bannana, could have been worked on ,hard to tell,same with injectors id be guessing. I believe Awesome dynotune in Adelaide did the tune and chip at the time and it put out 198kw ( must be fwkw ) before they put on uprated leads +plugs. Was wondering how many extra cubes would a 30th bore bring 2 or 3 ?,and do resized rods bring along any extra stroke ?, as ive said im really happy with it atm ,down the track may put in blue injectors and do some work on intake manny if not already done, but i suppose then id have to get the tune redone eh, cheers.

 

[Darren_L]

not sure about flywheel hp
but mine nosed over at about 250rwhp with the stock injectors and manifold
I picked up an additional 25rwhp with an aftermarket manifold and larger injectors

 

[ab56452001]

If it's rwkw id be more than happy and ill leave it alone, i gotta say i just sold my VT 5.0 5man with genie's and chip and i thought that was o'k',which it was !,but this thing,even being an auto (2200$spent on the box in 2010) is a real buzz taking off at the lights even without thrashing it. Ive driven a few 5.0 Vs/Vt and early 5.7 commy's and i really like this one the best, the sound is terrific !, got mates with latter 6.0l models with upgraded exhaust and they dont sound as nice !, they would most certainly kill me in a 1/4 mile , but gotta say there's something about the old Aussie v8,cheers.

 

[ab56452001]

Hi again. a bit more info, the TB has a dia of 80mm, is that stock ? , ta.

 

[Aussie V8]

Hi again. a bit more info, the TB has a dia of 80mm, is that stock ? , ta.

nope. 67mm (internal) I think from memory. MACE bores them out to 70mm to increase flow to as much as the stock manifold can handle. Any bigger and the potential extra airflow is pretty much wasted.

 

[Immortality]

Standard TB is 65mm. 80mm TB is total over kill because the neck/bend where the TB is mounted is about 69mm and the biggest restriction unless the manifold has been modified. It sounds like it has an LS1 TB fitted which would have required some cutting and welding if indeed it is 80mm I.D.

Stock bananas manifold can make good power, it's just crap for an engine that likes to rev, anything over about 5500rpm and the manifold starts to choke the engine. With your cam it shouldn't be a huge issue, also no need to change the injectors unless the standard ones run out of capacity which they won't with your list of mods

 

[ab56452001]

Thanks for reply , Immortality i just quickly put the tape measure over it without the tube off, outer diameter was around 80mm or more,as i said im happy atm and really im not worried about so called bs kw/hp figures cos ive seen guys claiming 200kw at the flywheel beat blokes bragging about supposedly 600hp cars !,i reckon we all have , im just curious about the mods made on my car,some i know of some i dont. The car is very streetable, it has to be , cos my wife and daughter both wanna drive it, thats why i bought it and thats why the VT manual had to go, but when ya push it it really moves, i love it !, and that sound !,cheers.