Header primary pipe sequence into collector for 4/7 swap

General engine tech -- Drag Racing to Circle Track

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redliner
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by redliner » Fri Oct 06, 2017 5:44 pm

strokersix wrote:
Fri Oct 06, 2017 5:33 pm
Little know speed secret: Collector pulse timing clockwise on the left side, counterclockwise on the right. This to create vortices on each side of the car reduce aero drag but you have to run tailpipes to properly place to vortex. Vette sidepipes even better.
Smokey took advantage of exhaust placement to use the slipstream of the car to suck the exhaust from the motor and suck the fresh intake charge in....

mk e
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by mk e » Fri Oct 06, 2017 5:46 pm

redliner wrote:
Fri Oct 06, 2017 5:42 pm
..... can you tell what I am thinking now????
I'll bet I can ;)

The answer is still 7k.

Then adjust the number you use for VE until the hp is 630-650 and the headers piprmax suggests will be realky good.
Mark
Mechanical Engineer

redliner
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by redliner » Fri Oct 06, 2017 6:04 pm

mk e wrote:
Fri Oct 06, 2017 5:46 pm
redliner wrote:
Fri Oct 06, 2017 5:42 pm
..... can you tell what I am thinking now????
I'll bet I can ;)

The answer is still 7k.

Then adjust the number you use for VE until the hp is 630-650 and the headers piprmax suggests will be realky good.
I am going with the numbers entered for the 7 grand. The difference in pipe sizing is minimal I am sure....

cjperformance
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by cjperformance » Fri Oct 06, 2017 6:29 pm

redliner wrote:
Fri Oct 06, 2017 6:04 pm
mk e wrote:
Fri Oct 06, 2017 5:46 pm
redliner wrote:
Fri Oct 06, 2017 5:42 pm
..... can you tell what I am thinking now????
I'll bet I can ;)

The answer is still 7k.

Then adjust the number you use for VE until the hp is 630-650 and the headers piprmax suggests will be realky good.
I am going with the numbers entered for the 7 grand. The difference in pipe sizing is minimal I am sure....
At the end of the day pipes a little small wont really hurt too much but pipes a little big will. If Mike indicates 630-650 @7 then personally i would adjust pipemax to 630 then 650 and look at what closest available matching pipe sizes are that you can get, if you cant decide try 640@7 aswell. If you have a couple of matching pipe sizes Id go for the closest matching smallest pipe.
Craig.

redliner
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by redliner » Fri Oct 06, 2017 6:40 pm

cjperformance wrote:
Fri Oct 06, 2017 6:29 pm
redliner wrote:
Fri Oct 06, 2017 6:04 pm
mk e wrote:
Fri Oct 06, 2017 5:46 pm


I'll bet I can ;)

The answer is still 7k.

Then adjust the number you use for VE until the hp is 630-650 and the headers piprmax suggests will be realky good.
I am going with the numbers entered for the 7 grand. The difference in pipe sizing is minimal I am sure....
At the end of the day pipes a little small wont really hurt too much but pipes a little big will. If Mike indicates 630-650 @7 then personally i would adjust pipemax to 630 then 650 and look at what closest available matching pipe sizes are that you can get, if you cant decide try 640@7 aswell. If you have a couple of matching pipe sizes Id go for the closest matching smallest pipe.
The point you all are missing is, I was NEVER told the maximum rpm the cam is making power at... I was told 630 @ 6800 and 650 @ 7000 ( 7000 was the requested redline when I ordered cam). So yes I tend to ASSUME..... that max power is at 7000... but we allll know what happens when we ASSUME!!!!

RevTheory
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by RevTheory » Fri Oct 06, 2017 7:49 pm

Where are you planning on upshifting this engine?

redliner
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by redliner » Fri Oct 06, 2017 7:53 pm

RevTheory wrote:
Fri Oct 06, 2017 7:49 pm
Where are you planning on upshifting this engine?
Thats another reason I would like to know max rpm/ hp. I will call Mike sometime and get the particulars. I think I want to shift my 4-speed 500 rpm past max hp dont I? Thentrap 500 past max hp rpm? Prolly 7000 or 7500 rpm shift?

mk e
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Re: Header primary pipe sequence into collector for 4/7 swap

Post by mk e » Fri Oct 06, 2017 8:57 pm

redliner wrote:
Fri Oct 06, 2017 7:53 pm
RevTheory wrote:
Fri Oct 06, 2017 7:49 pm
Where are you planning on upshifting this engine?
Thats another reason I would like to know max rpm/ hp. I will call Mike sometime and get the particulars. I think I want to shift my 4-speed 500 rpm past max hp dont I? Thentrap 500 past max hp rpm? Prolly 7000 or 7500 rpm shift?
Shift point is about getting the most toque to the ground. There are times of thumb to estimate like shift at the hp peak but also high enough to stay above tq peak....but

Those are guesses. If you have the dyno sheet you can calculate the optimum shift point. Makes or find a spread sheet that has your drive ratio (gear ratio times rear ratio) for each gear, times the engine tq which gives you the power to the wheels.....and you want the biggest number you can have do graph it vs rpm and the highest line is the winner. Usually it will work out that in low gears you want to shift at redline and higher gears you shift around the hp peak, but the graph will make it obvious.

The exception is reaction in lower gears...sometimes you are traction limited and need to keep wheel torque below the wheel spin number...more a road race or spec tire class thing, I fix it with traction control when that's the case.
Mark
Mechanical Engineer

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