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Discussion Starter #1
What is the most you have made with on pump gas and being naturally aspirated with a SBC. Please give some details as to heads and what did the car run. Im looking for about 800 hp on pump and will be using rfd 15* heads, just looking to see what people have done. Thanks
 

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well there is a guy on here making well up in the 700 on pump gas and naturally aspirated with a 402 sbc with 23 * heads so 800 with 15* can be done !
 

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Chris U did one with a set of 15* heads a year or so ago....turned out real nice...cant remember the power ##'s... but i know it was impressive.
 

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well there is a guy on here making well up in the 700 on pump gas and naturally aspirated with a 402 sbc with 23 * heads so 800 with 15* can be done !
He is talking about mine..............vid is in the sig. 4.130x3.750 23 degree Dart Pro 1. Cam is 272/286 .866/.847. Cast Manifold, single 1050. Averages 723 from 6600-8300.

Going in a 3600lb 67 Chevelle...........Ill have track times as soon as the snow melts :D My crabby engine builder is holding out on me as far as pictures goes, but here are some videos............

Our thoughts are run this for a couple years, and start working on a Little Chief Pump gas deal for Drag Week.

http://www.youtube.com/watch?v=BMIUJtvdePU
http://www.youtube.com/user/Tom3VPerformance#p/a/u/2/jsHuHrI66K8
http://www.youtube.com/user/Tom3VPerformance#p/a/u/0/EE6weXGMQds
http://www.youtube.com/user/Tom3VPerformance#p/a/u/1/70WIZYlIPTw

Any questions let me know..............No doubt in my mind you can make 800 with a 15 degree head and some cubes........but I would be looking more at the average power. Thats where its at. :D
 

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Unfortunately it hasn't made it into a car yet...:( My goal is for the engine to run bottom 9's at approx 3000 pounds. If I was allowed at the time to put more camshaft in the engine and a larger carb I am confident it would be an 8 second engine.
 

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Discussion Starter #7
Well my motor made some pretty good power for nothing special car is 3300 #s and went 10.16 @ 132 1.45 sixty foot this is off the trailer with no carb jetting and 30 degress of timing and no adjustment to my suspension which is in need of some serious help. Leaving off the foot brake also.

434 11.1 compression AFR 235 heads
264 272 678 654 109
2925 super victor ported by cfm and 1000 hp done by prosystems
1 7/8 headers
4.56
turbo 400 4500 nitrousnconverter from ptc
caltacs and spit monos. 28 x 10

I think im making in the 600 plus range so looking for a nice 800 hp pumpgas motor.
 

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I would say, Flyin Ryan has got to be right up there.




Quote me if I'm wrong, but I'm fairly sure I was the only guy in Hot Street in Vegas running a 4150. I'm fairly positive I was the only one running pump gas, but that wasn't the question, just sayin'.
 

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How many times does it have to make it? I think I could run Pump gas at the track If I tuned for it. I run it on the highway and loads with a trailer behind with no signs of anything on the pistons or plugs. I just tune to race fuel so it stays the same Tank after tank from state to state on Drag Week
 

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keep in mind that offset lifters do not get anywhere near the life of a standard lifter due to uneven bearing loads

thats why building a pump gas motor that will actually be driven needs parts that will handle the miles as well

that is where 18 and 15 degree pump gas exotic motors on the street wont last too long
 

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That is true. In an offset lifter bearing and lifter loads are uneven but, your data is based on drag race profile, aggressive camshafts with aggressive spring pressures.

With relatively light spring pressure and a cam lobe that is continuous duty friendly there is no reason to assume that there will be lifter issues because the pushrod is moved .180".

There are many, many examples out there on the street with lifter offsets successfully. Even many 23 degree heads require or will benefit from a lifter offset due to the pushrod geometry.

Lifter loads are not even, with a center pushrod and not having the pushrod straight...... FOOD FOR THOUGHT.

Keep in mind, that the more efficient the combustion chamber, and the more efficient and capable the induction system.... the less camshaft is required to achieve the desired output.

My engine above has a 255 @ .050 intake lobe... and with a very friendly profile, and not a lot of spring pressure.... and will run to 8000+ if need be. But there is no reason with the above engine to operate above 7500 to achieve it's goals.... further lending to reduce spring mass/pressure and ultimately lifter loading.

Based on all that said, it should be the goal of anyone looking for the ultimate pump gas engine, to work with the best induction they can get their hands on.... allowing IT to do the work.... with less rpm and valvetrain to achieve goals.

Your original premise has merit... why would I want a 9000 rpm pump gas street engine?
 

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Big Arm, Great induction, Small Cam, minimum rpm to achieve reasonable and respectable hp goals, = long life for pump gas street engine.
 

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Discussion Starter #15
Chris, what do think of my pumpgas combo, and what do you feel i would gain with 15* rfd heads and the right cam, intake, and headers as in et and hp. thanks
 

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That is true. In an offset lifter bearing and lifter loads are uneven but, your data is based on drag race profile, aggressive camshafts with aggressive spring pressures.

With relatively light spring pressure and a cam lobe that is continuous duty friendly there is no reason to assume that there will be lifter issues because the pushrod is moved .180".

There are many, many examples out there on the street with lifter offsets successfully. Even many 23 degree heads require or will benefit from a lifter offset due to the pushrod geometry.

Lifter loads are not even, with a center pushrod and not having the pushrod straight...... FOOD FOR THOUGHT.

Keep in mind, that the more efficient the combustion chamber, and the more efficient and capable the induction system.... the less camshaft is required to achieve the desired output.

My engine above has a 255 @ .050 intake lobe... and with a very friendly profile, and not a lot of spring pressure.... and will run to 8000+ if need be. But there is no reason with the above engine to operate above 7500 to achieve it's goals.... further lending to reduce spring mass/pressure and ultimately lifter loading.

Based on all that said, it should be the goal of anyone looking for the ultimate pump gas engine, to work with the best induction they can get their hands on.... allowing IT to do the work.... with less rpm and valvetrain to achieve goals.

Your original premise has merit... why would I want a 9000 rpm pump gas street engine?
What is going to go down the track quicker........800Hp at 5000rpm, or 800Hp at 8500?

To me what I was after was a program that gets with it quickly, and hangs on. We are above 615Hp at 5800, and the entire sweep from 4600-8300 averages over 620.

I like that you brought up spring pressures and cam profiles.......that was a major focus during my build. Chris on your 15 degree deal, it says that it made 770Hp, what is the average over its intended rpm?
 

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hp

500 at 4500
590 at 5000
706 at 6000
750 at 6500
770 at 7000
peaks at 772 at 7200
770 at 7500

Torque

550 at 4500
616 at 5000
626 at 5500
626 at 6000
610 at 6500
577 at 7000
536 at 7500

Thats an efficient combustion chamber and a killer intake port.

That kind of torque, and resultant hp can't be achieved with a 23 degree chamber and port.

There have been modifications to the manifold to help with the intended rpm range also....

Jake if you take all your cam and valvetrain development and couple it with a killer set of heads and intake.... you would be very surprised at how your average starts to look, and how much torque and hp you would gain.

I'm building a 456 CID version of this engine right now with a raised cam deal/tall deck, and I'm going to push the limits of compression and camshaft with it... I'm pretty excited. ;)

When we build a max effort 420-ish n/a engine with the same 15-ish degree head and mopar intake... we make over 900 hp at 7000, with high 900's peak at 9200+... consider that average.
 

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Interesting numbers there. The question has been the limits on static compression and lobe configuration lift, ramp, etc. with a given head and intake (for me in and EFI set up single four barrel configuration) with a single tune for 91 pump gas as thats what we get here in Cali. I've made one bad tuning mistake at the track and fire slotted the head on one 1/8th mile pass so I'm a little nervous about how far to push on the pump gas.

Setting it up around a race gas tune for the track and then a separate tune for the usual driving around makes for an interesting alternative on the 'pump gas' numbers.
 
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