15 replies to this topic

[Redslur]

Hi all

 

Has anyone here ever used, or know of someone who has, the Star Performance Manifolds for the Holden 304 V8's? They adapt a larger 92mm throtle body to the original manifold and state that is provides up to 22% more power than the standard version.

 

I am looking to get any advice prior to purchasing one and fitting it to an injected engine I want to fit into my Torry. I really want to keep the original look and I know there are better manifolds out there.

 

Cheers,

Gerry

[Redslur]

I will actually be looking at putting the manifold on another engine I have to install.  It is a 355 stroker.  The stocka was never part of the plan :-)

Edited by Redslur, 01 January 2014 - 05:12 PM.

[Redslur]

Yep it does but don't have a clue how it works.  Got all the goodies I need for my project. Already have tidied up several things.  Car will come up real nice when I am finished with it.

[Litre8]

I am always wary of claims like 'provides up to 22% more power' since 'up to' includes zero.Or the 'up to' requires multiple other component changes to exploit the potential.

[Redslur]

Yep agree.  Hence me asking for advice here. Always to good to get people's oppinions that have actually tried the product.

[76lxhatch]

I recall reading another thread on these recently somewhere, and apparently the only change was adapting the larger throttle body? That's not going to improve overall performance

[Redslur]

A larger throttle body will increase performance.  One of the first things people do to their LS engines. The 304's are only about 65-70mm standard. Goin up to a 92mm increases flow but whether or not a gain of 22% is achievable is what I am interested to hear?

Edited by Redslur, 02 January 2014 - 08:08 AM.

[76lxhatch]

Increasing the throttle body size will not increase performance if it is not the bottleneck. A 22% increase in the flow of the throttle body means squat if no other part of the intake system will handle this flow.

Larger throttle bodies will give the feeling that the engine is more responsive, this is because in comparison to the smaller one you require less throttle percentage to achieve the same air flow. So, the pedal supplies air faster at small percentage openings. At higher percentage openings it does next to nothing because the throttle body is too big and the engine can't use the additional air; effectively you lose fine control. There isn't really any point in having a throttle body that supplies all the air the engine can handle when half open.

Standard is 65mm. I can see a small increase in size being beneficial, particularly if its a stroker. However with the standard manifold 92mm is a waste of time and money. Of course, all this assumes that what I read previously is correct about it being only a throttle body change. If the manifold has been opened up as well that changes things.

[xu1kid]

they actually cut the neck off and put a bigger neck on it also has a air divider in the neck to help the air turning and the throttle body is 90 mm , i have one on my cammed 355 vs senstor , my motor is real torqy im happy with its perfomance on the street , maybe a bit big for standard 5 litre ,

they claim standard manifold flow around 550 cfm and starr manifold 1200 cfm

[TerrA LX]

A larger throttle body will increase performance.  One of the first things people do to their LS engines. The 304's are only about 65-70mm standard. Goin up to a 92mm increases flow but whether or not a gain of 22% is achievable is what I am interested to hear?

Just exactly HOW does a larger throttle body increase power? (without other mods, such as re mapping, raised rev limiter/cam etc).
In reality, all it is doing to "increase performance" is decreasing the amount you have to crack the throttle open for the same air flow, or if you open the throttle the same amount then it will feel like you are getting more performance via the placebo effect the increased airflow provides.

[xu1kid]

they way i think of it suck through a straw then suck through a 8 mm hose big difference in restriction . i think theyr less restrictive than a stock manifold and good for a torquey street motor not a high end screemer

[Redslur]

Thanks XU1kid.  You have provided me with the information I require.

 

Cheers, Gerry.