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Stock Eliminator secrets?

General engine tech -- Drag Racing to Circle Track

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S10LS2
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Re: Stock Eliminator secrets?

Post by S10LS2 »

maxracesoftware wrote: Wed Sep 09, 2020 5:41 pm very nice Artice + great Engine Parts Pics .... about NHRA L/SA Stocker 283cid Chevy
with Engine by Tony Bischoff of BES Racing

Wade Owens 1966 Chevelle

11.571 ET @ 113 MPH

Peak TQ = 342.0 at 5000 RPM
Peak HP = 373.0 at 6500 RPM

As of this writing, the car has garnered eight class wins and six No. 1
qualifying positions and has run as fast as 11.571 in L/Stock Automatic.

https://www.hotrod.com/articles/1209em- ... 283-chevy/
But but only 375 hp at 6500 ? Good thing bes does not post here he would be ridiculed.. The "legends" here say they have built or seen 283/293 cid WELL in excess of 500-550hp at 8500 rpm.. With the exact same heads and valve sizes 2hp per ci is the norm here it seems from what I have read. (look at the 283 500hp thread here). Stand up builders like bes show where the BS starts and stops.. Further more no secrets, engine recipe is in the article
wwmtlineman
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Re: Stock Eliminator secrets?

Post by wwmtlineman »

Maybe an Super Stock 283/220 engine could make that, but I doubt a a stocker would
Chris_Hamilton
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Re: Stock Eliminator secrets?

Post by Chris_Hamilton »

Stock Eliminator and Super Stock are two fairly different classes. :oops: Apples and oranges.
What's with the attitude btw?
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Re: Stock Eliminator secrets?

Post by rustbucket79 »

tenxal wrote: Wed Sep 09, 2020 8:11 am
rustbucket79 wrote: Tue Sep 08, 2020 11:44 pmThe true essence of stock died with roller rockers, intake runner CC volumes, (we know you’re porting heads) and lack of tear downs and tech officials that know what a proper bowl looks like on a 70 400 Pontiac and a 66 426 Hemi.
The after market rocker rule is one that made sense and should have been in place even before the valve spring rule was lifted.

When the valve spring rule was lifted, the 'stock rocker arm' rule was kept in place. The rockers became the weak link in the chain..no telling how many engines were lost or damaged from rocker failure. In the case of the big block Chevy stuff, some savvy racers developed a 9/16" stud/rocker/ball assembly that while heavy, helped with breakage. The problem was, this 'stock' setup was close to $1,000 while a quality roller rocker set was about half that. There's generally little or no gain with a roller rocker (just the opposite is possible for those who actually test this stuff :wink: ).

The intake/exhaust runner volumes are also a way to try to control the creative head work. In general, it works well. However, as NHRA reduced funding of the Technical Services personel at both the Divisional and National level, racers and engine shops continued down the path of covering up the work....to the point that a set of really good Stocker heads now requires significant money to be spent just to cover up the work that's been done.

As a racer, you can either accept that and allocate the resources or be conservative and not be as quick as the fast guys.

There is a lot of E.T. in the drive train and other places that you can 'find' for a fraction of the money spent on head and intake work.

I race with and respect people that take both approaches.

Image
Stock ain’t stock, and there was far more honour 20/30 years ago than the bastardized super stock cars these “stockers” are today.
tenxal
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Re: Stock Eliminator secrets?

Post by tenxal »

RDY4WAR wrote: Wed Sep 09, 2020 4:12 pmI've been trying to study this part pretty extensively. I know stockers run some rather steep gearing. Are they aiming for 200-400 rpm above peak HP at the top end or are they letting it ring out 1000+ rpm. Are they gearing for it to pull all the way through or do they have their tongue out on yhe top end just waiting for the finish line?
It depends on the power/torque curve of the particular engine. Convertor slippage also plays a big part in how you set the car up.
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Re: Stock Eliminator secrets?

Post by vortecpro »

A Super Stock 283 makes around 530 HP I believe. BUT the BES 283 stocker is a perfect example of what I've said about stockers, sure it made 373 HP in stocker trim, but what nobody is talking about is how this engine carried HP past peak which allowed this combination to utilize a 7 inch converter and did run 11.40s in M/SA with if I'am not mistaken a 1.44 60 foot, think about that 60 @ 11.40s. Perfect example of power utilization.
Racing a NA NHRA stocker should be mandatory before any posting.
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Re: Stock Eliminator secrets?

Post by engineguyBill »

Basically, Stock Eliminator engine builders strive to reduce the internal friction within the engine. Reducing the rotating assembly weights is not possible under the rules, therefore camshaft design becomes a very important aspect of these engines. The whole engine design, then the chassis/running gear is given equal attention. Many racers do things that are not necessarily illegal, but may involve "stretching" the ruled slightly. I know a very successful Stock/Super Stock racer who puts every sentence in the rule book into a spread sheet, then he makes notes as to why that rule is in place, followed by several notes about how the subject of this sentence may be "tweaked" to make more power. Building these engines has become a science to say the least. BTW, the majority of NHRA tech inspectors that I have known over the years are very knowledgeable and competent individuals . . . . . . . .
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Geoff2
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Re: Stock Eliminator secrets?

Post by Geoff2 »

Yes, 'stretching' the rules. Smokey Yunick did the opposite & 'shortened' the rules when be built a car that was shorter than the stock model. There was nothing in the rules about shortening....
tenxal
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Re: Stock Eliminator secrets?

Post by tenxal »

S10LS2 wrote: Wed Sep 09, 2020 6:46 pmBut but only 375 hp at 6500 ? Good thing bes does not post here he would be ridiculed. The "legends" here say they have built or seen 283/293 cid WELL in excess of 500-550hp at 8500 rpm.. With the exact same heads and valve sizes 2hp per ci is the norm here it seems from what I have read. (look at the 283 500hp thread here).
The engines I referenced in that thread are Super Stock class engines, not Stock class engines.

Super Stock class, while requiring the O.E. valve sizes and chamber/port cc's, allow the heads to be welded, epoxied, etc. Additionally, you can use any camshaft, cam drive mechanism, intake manifold and any oil pan. Jesel and T&D shaft rockers are commonly used as well as front drive ignition systems and belt driven cams.

Stock Eliminator engines must have the factory valve lift for the engine horsepower claimed (.390/.410 for a 350/255 horse SBC, for example), factory intake, factory carb, factory config on the piston tops, factory ring widths, stock or NHRA accepted replacement oil pan, factory rocker arm mounting config (no shafts if it came with a stud) factory cam drive config and the heads cannot be welded/epoxied.

There's more but that a good overall view of the engine differences.
6.50camaro
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Re: Stock Eliminator secrets?

Post by 6.50camaro »

The article Mr Meaux linked was originally in Engine Masters Magizine I do believe . I have the mag packed away in a box with my other tech manuals and catalogs. In the middle of a move at the moment so I can't put my hands on it for awhile. But the original article had more photos and more text describing the testing of different oil pans, scrapers , that went into the final product . Also there was a pic of the empty bottom end a if you had a keen eye you could see Windows milled in the main bearing bulkhead to allow for less pumping loss on the piston down stroke . The cam tunnel was in closed with what looked to be beer cans so no oil dripped on the rotating crank . There were a few other thing but the memory is a little rusty because I haven't looked at that article in a couple years . But my hat is off to all those who push the limits in a rules restricted classes be it newer looser rules or the old strict stock rules. I agree it's attention to detail . Sometime you can tell a good prepped car just watching them push it in the staging lanes. Dan
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Re: Stock Eliminator secrets?

Post by classracer »

I had an old Stock / Super Stock racer tell me in my early days to read the NHRA rule book (stock section), and it will tell you how to go fast. What ever you are prohibited from doing will make your car fast. The trick is to make the engine and chassis think you are doing those things, but stay with in the rules. Sounds simple, not really as I'm still working on it. Do racers push things? You bet they do, some more than others.
There have been many enhancements in our class. What I will tell you is that every time changes are allowed, it cost me more money. Do I take advantage of these changes? Yes I do, but at my pace and what I can afford at that time. Would I like the rules to go back to a previous time? Yes I would, but I know it will never happen and honestly it is not piratical.
When people start talking about acid ported heads, I can tell how much they do not know. Things are a little different now. I know some racers that have modified heads and I know some that do not, and how fast they are is not an indication of what has been modified or how much they are modified. I have flowed many heads and found some really good flowing stock ports. The problem is the core shift that make that port flow good also causes other ports to flow poorly. Trying to find a head with 4 ports that flow well or average is the task. Working with in the rules, is at times a pain, but I love it.
A short story: I was at the track testing the car (time runs and a few rounds if I'm still in (no buy backs)). I was in the lanes next to a real nice 70-71 Chevelle street / strip car. While waiting we got into a good general conversation about both cars. He said his engine was dynoed at a little over 630 hp and seeing as how fast I was running my engine had to be 650 to 700 hp. I told him that I have not had the engine dynoed, but I would be tickled if made 550 to 570 hp. The staging lane were moving up, him and his two buddies were all but grunting to push his car up. I had one hand on the side back of my car and pushed it forward (it rolls rather easily). He just shook his head and said that's unbelievable. With a stocker horse power is important, but there are many other things that make them run well.

Jim
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Re: Stock Eliminator secrets?

Post by dannobee »

Any engine related advice I could give would be dated, but I can offer some advice on "freeing" up the car.

"Adjust" the bump steer so that the toe stays within 0.005" per inch of travel. And when I say "adjusting," you might need to heat and bend the steering arms on the spindles. And back off the front wheel bearings at least a flat or two so that the caliper pistons get pushed back into the bores and keep the brake pads from dragging the rotors.

One seldom mentioned factoid is that the rear end housing toes in on acceleration. Some housings are inherently weaker than others. If you get out the porta power and set the rear toe out a bit, when the car is launching the rear toe will be closer to zero.

When you're fighting over thousandths of a second with limited power, every little bit helps.
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Re: Stock Eliminator secrets?

Post by engineguyBill »

The elimination of bump steer will make a significant difference in the vehicle's dragstrip performance. Bump steer can be very efficiently controlled by relocating steering box and idler arm on the frame (up or down) and by contolling the arc of the tie rod ends to the same arc as the lower control arm. Lots of work to get it all set up and functioning, but better than heating the steering arms. Many other tricks available for reducing or eliminating drag throughout the chassis.
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KnightEngines
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Re: Stock Eliminator secrets?

Post by KnightEngines »

I build for a few heavily restricted road race classes.
One of the guys spent days on a chassis dyno just testing gearbox & diff oils to find which produced the least drag. He found something like 3hp at the tyres & was dead happy about that.
He also spent time testing pinion angles etc for least power loss.
Wheel bearing grease is another place to find reductions in rolling resistance, even ceramic bearings with oil instead of grease.
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Re: Stock Eliminator secrets?

Post by dannobee »

Sometimes heating up the steering arms is all you can do after exhausting all other options. Which brings up another point. What flies in Div 7 might be a hard DQ in another division, depending on the tech official. The closer you "appear" to be "stock," the less attention it'll attract.

I knew one stocker guy, a "chronic cheater," who would always make something illegal plainly obvious, to distract the tech from the real cheating in other areas.

With respect to bump steer, we'd check the circle track cars every week for alignment, bump steer and scaling. The stocker guys across the street (literally, their shop was across the street) saw me checking bump steer and came over, asking if they should do it on a drag car. Yup, you should. I showed them what to do on one of their stockers (bump steer and a "real" alignment) and they claimed it ran almost a tenth quicker and went straight as an arrow all the way down the track. Don't just casually dismiss not having to saw the wheel to keep the car going straight. If you're turning the steering wheel, you're scrubbing off speed.

A big plus on the synthetic fluids/greases. We had a Lucas Oil sponsorship and they gave us a bunch of free product. At first I thought, whatever, what difference does wheel bearing grease make. Now I'm convinced and will only run synthetic grease. The green Xtra Heavy Duty grease works great on wheel bearings.
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