Rocket Port Work

Here are some pics of Bob-DC2's head I G'd up for him.

I would like to thank MAX_CFM and Omniman their helpful guidance.

Scrubbed Intakes


Intake Bowl Blending (I didn't smooth out the chamber because the head already has a valve job(VJ) and I didn't have cut down valves to protect the VJ.


Reworked Exhaust with a Carbide Cutter Only

 

Looks pretty clean there Rocket. Any flowbenching happening any time soon??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MaxBoost &raquo;</TD></TR><TR><TD CLASS="quote">Any flowbenching happening any time soon??</TD></TR></TABLE>

No we are just gonna throw Bob-DC2's car on the dyno with low lift m23 cams and see what the torque curve looks like. This will effectively tell me how the head flows.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rocket &raquo;</TD></TR><TR><TD CLASS="quote">

No we are just gonna throw Bob-DC2's car on the dyno with low lift m23 cams and see what the torque curve looks like. This will effectively tell me how the head flows.</TD></TR></TABLE>

how would the dyno tell you how much the head flows?

how are you going to determine the percentage of flow and the rate fo the flow by using a chasis dyno?
i dont understand....

 

I think he's just going to compare before and after dyno numbers to see how much power it gained from the works.

I think flow bench number doesn't mean much anymore. You can have a really big *** port and huge flow number, but it doesn't mean anything if your head is not making any power. Just my $.02.

 

Here's a dyno curve from a CRV-VTEC. It has the very characteristic 5.5-5.8k rpm torque hump and it's down hill after that.

What I would be looking for is to see if the whole combo breathed better is if the torque curve has less of a down hill or even flat curve after 5.5k rpms. This will tell me if the hole entire engine (Intake, IM, Head, Header, Exhaust) is flowing well and can support the air flow required to make power longer in each gear.

 

Please post the dyno charts after the install.

 

great job

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fox297 &raquo;</TD></TR><TR><TD CLASS="quote">
I think flow bench number doesn't mean much anymore. You can have a really big *** port and huge flow number, but it doesn't mean anything if your head is not making any power. Just my $.02.</TD></TR></TABLE>

a flowbench not meaning much?

a flow bench checks the intake and exhaust flows at different rates (lift) and tells you the percentage of the ports efficiency at those rates. (how much air is going through)

so if a flowbench tells you when and where the best air flow or increase in cfm is how can it "not mean much anymore"?

what a flow bench does do, is tell you where it needs or where it doesnt need to be ported.


what a flowbench does is help you find where exactly you need to work on the head in able to increase the flow wherever you are trying to focus the power.

then of course one would as welll flow the intake manifold and exhaust if it is that critical.

some people can even determine what work needs to be done to the exhaust and manifold just by the flow numbers fropm the head.

so flow numbers are very important, and flow benching is very important to make power out of the head.

you need to know what you are doing and not just go into a head and automatically think big port is better.

so if you dont know what air is flowing through where, how can you know where to port and where not to?

how would you know if you made it better or made it worse?

how are flow numbers not important?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rocket &raquo;</TD></TR><TR><TD CLASS="quote">
What I would be looking for is to see if the whole combo breathed better is if the torque curve has less of a down hill or even flat curve after 5.5k rpms. This will tell me if the hole entire engine (Intake, IM, Head, Header, Exhaust) is flowing well and can support the air flow required to make power longer in each gear.
</TD></TR></TABLE>

i can understand that, though there are to many factors that can cause you to believe it is not flowing well. and if it doesnt flow as expected, what would you do then?
would you take the head back off and work the ports some more?

where would you know what to do or not to do next time?

 

I know that a flow bench is a vital tool to any head porters. You can't really know what you're doing unless there are some flow number to guide you.

What I meant was: there are people out there who go around bragging that this head have better flow number than that head and such while higher numbers do not neccessary mean more horsepower.

Nowaday, people are looking into high-velocity port for power and such port does not neccessary have the highest cfm.

 

The thing I don't understand is if you are using a flow bench as guidance then how do you know were the limit is until you go past it and have a negative affect.

This is not an argument, just want to learn something.

 

this is turning into a good thread. but hell, im just excited to get my head back this week and get my car running after a long 2 month, actually almost a 3 months wait