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importance of and improving power curve

General engine tech -- Drag Racing to Circle Track

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Firedome8
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Re: importance of and improving power curve

Post by Firedome8 » Sun Oct 28, 2018 12:32 pm

steve cowan wrote:
Sun Oct 28, 2018 3:45 am
Good link Bill,thanks
there is a life time of reading just there :D
http://www.impulsengine.com/how/header.shtml

Any thoughts on this.

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Re: importance of and improving power curve

Post by randy331 » Sun Oct 28, 2018 1:26 pm

Firedome8 wrote:
Sun Oct 28, 2018 12:32 pm


http://www.impulsengine.com/how/header.shtml

Any thoughts on this.
Lots of theory and no real results that I found on there.

The one thing that I don't think would work out on a pulling truck engine (and most other engines) is,.. The need to close the ex valve before TDC. It shows that on that website. Special valve timing needed. My current EVC at .050" is 29* ATDC. Later than that for seat timing.

Randy

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Re: importance of and improving power curve

Post by GARY C » Sun Oct 28, 2018 3:43 pm

Randy, have you talked to Calvin? He seems pretty willing to share size, length of each step and collector for a given engine when I had talked to him in the past.
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Re: importance of and improving power curve

Post by 77cruiser » Sun Oct 28, 2018 5:30 pm

GARY C wrote:
Sun Oct 28, 2018 3:43 pm
Randy, have you talked to Calvin? He seems pretty willing to share size, length of each step and collector for a given engine when I had talked to him in the past.
I thought so when I talked to him.
Jim

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Re: importance of and improving power curve

Post by MadBill » Sun Oct 28, 2018 7:38 pm

Yes, interesting theory but getting the cam 'right' for it in a specific engine would require a lot of testing. Also, specs seem to be specific to a couple of unnamed unique Down Under engines.

Wonder what nitro2 would make of it?
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Re: importance of and improving power curve

Post by randy331 » Sun Oct 28, 2018 9:25 pm

77cruiser wrote:
Sun Oct 28, 2018 5:30 pm
GARY C wrote:
Sun Oct 28, 2018 3:43 pm
Randy, have you talked to Calvin? He seems pretty willing to share size, length of each step and collector for a given engine when I had talked to him in the past.
I thought so when I talked to him.
I planned on contacting him, but wasn't at a point I'm ready to build a set at this point, and didn't want to waste his time being a tire kicker.

I keep thinkin I'll get some time to run it back to the dyno to test these we ran this year vs something else bigger. That data could help the sizing question. But,... I seem to keep gettin more engines in to work on. Tore another BBC pullin truck engine down today a guy bought and brought up.

I'm sure something bigger than 1 5/8 x 1 3/4 step we ran this year will give it some power, but I've been disappointed with dyno expectations before. LOL :)

Maybe 77cruiser would like to build set for me. :wink:

Randy

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Re: importance of and improving power curve

Post by Ron E » Sun Oct 28, 2018 9:48 pm

MadBill wrote:
Sun Oct 28, 2018 7:38 pm
Yes, interesting theory but getting the cam 'right' for it in a specific engine would require a lot of testing. Also, specs seem to be specific to a couple of unnamed unique Down Under engines.

Wonder what nitro2 would make of it?

I'd really like to hear his thoughts on it as well.

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Re: importance of and improving power curve

Post by cjperformance » Sun Oct 28, 2018 10:02 pm

MadBill wrote:
Sun Oct 28, 2018 7:38 pm
Yes, interesting theory but getting the cam 'right' for it in a specific engine would require a lot of testing. Also, specs seem to be specific to a couple of unnamed unique Down Under engines.

Wonder what nitro2 would make of it?
Basically they are building torque based ultra mild engines, then run the coolant cold and intake air hot and tell you that when that hit intake air hits the 'cold' chamber it condenses and allows more air to enter the chamber than otherwise would. Ultra mild cams and small tube headers, decent tq down low and a bit of advertising hype and suddenly you have -ve supercharging!
Craig.

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Re: importance of and improving power curve

Post by cjperformance » Sun Oct 28, 2018 10:03 pm

Ron E wrote:
Sun Oct 28, 2018 9:48 pm
MadBill wrote:
Sun Oct 28, 2018 7:38 pm
Yes, interesting theory but getting the cam 'right' for it in a specific engine would require a lot of testing. Also, specs seem to be specific to a couple of unnamed unique Down Under engines.

Wonder what nitro2 would make of it?

I'd really like to hear his thoughts on it as well.
Same!
Craig.

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Re: importance of and improving power curve

Post by randy331 » Sun Oct 28, 2018 10:05 pm

CGT wrote:
Fri Oct 19, 2018 11:57 am

Interesting, whats your thought behind speeding up the exhaust valve, rpm I would guess? Weren't you considering switching over to the 14 degree heads? The headers and the carb seem to be no brainers. Which 18° manifolds do you have? I would want to look at the condition of the current seats, after going through those extreme conditions before going to a steeper VJ.
Just thinkin it may benefit from a little more time/area on the ex lobe. It's currently a slow ex lobe cause it still has a steel ex valve is one reason, and I knew how it would be treated. LOL

The 14* probably won't happen for 2019.

I have a GM one and one other. I'd need to go look at it again.

I don't expect much problem with seats on tear down. The lash hasn't been changing. I changed one ex valve after the first rev limiter hit (first night out) and none the rest of the year.

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Re: importance of and improving power curve

Post by 77cruiser » Mon Oct 29, 2018 9:32 am

randy331 wrote:
Sun Oct 28, 2018 9:25 pm
77cruiser wrote:
Sun Oct 28, 2018 5:30 pm
GARY C wrote:
Sun Oct 28, 2018 3:43 pm
Randy, have you talked to Calvin? He seems pretty willing to share size, length of each step and collector for a given engine when I had talked to him in the past.
I thought so when I talked to him.
I planned on contacting him, but wasn't at a point I'm ready to build a set at this point, and didn't want to waste his time being a tire kicker.

I keep thinkin I'll get some time to run it back to the dyno to test these we ran this year vs something else bigger. That data could help the sizing question. But,... I seem to keep gettin more engines in to work on. Tore another BBC pullin truck engine down today a guy bought and brought up.

I'm sure something bigger than 1 5/8 x 1 3/4 step we ran this year will give it some power, but I've been disappointed with dyno expectations before. LOL :)

Maybe 77cruiser would like to build set for me. :wink:

Randy
Thanks for the offer. :P
Jim

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Re: importance of and improving power curve

Post by randy331 » Sat Nov 02, 2019 12:45 pm

Turn the volume up.
The 421 in a different truck than last year.



Just needed rpm for this pull. 9400 rpm mid track and only pulled it down to 7500 ish at the end.
Spun out easy cause it pulled the sled out past the track prep.



A pull where more power anywhere from 2500-8500+ rpm would have helped.
First time the 421 has been snuffed out at the end.
Best track we ever been on.

Randy

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Re: importance of and improving power curve

Post by steve cowan » Sat Nov 02, 2019 7:29 pm

hey,Randy,
any chance of the 421 going in your new car :wink:
steve c

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Re: importance of and improving power curve

Post by randy331 » Sat Nov 02, 2019 8:53 pm

steve cowan wrote:
Sat Nov 02, 2019 7:29 pm
hey,Randy,
any chance of the 421 going in your new car :wink:
There has been talk of that.
Not sure it'd be much faster than the engine in it, the power isn't too far off.

Randy

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Re: importance of and improving power curve

Post by CGT » Fri Nov 08, 2019 11:00 am

randy331 wrote:
Sat Nov 02, 2019 12:45 pm
A pull where more power anywhere from 2500-8500+ rpm would have helped.
Well since ST seems to be experiencing low traffic flow or low interest flow....I'll ask.. what changes need to be made to improve power over a 6000rpm wide range? :lol: :lol: Nitrous? :D
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