Here's the car I use for most of my testing. The primary engine is a mild 355, stock bottom end, cast crank, stock rods and hyper 4 Valve relief flat top pistons. To get the static compression up in the high 11s I run iron topline heads with 50cc combustion chambers. I run a solid flat tappet cam with 263/268 degrees duration and .550 lift.

Running exclusively 100 octane low lead; when I first ran the engine unmodified it was detonation limited. I pulled the heads twice for modifications. I'm at a point now that I need more cylinder pressure or lower octane fuel to continuing detonation limitation testing. The heads are milled to the max; my options are pistons with two valve reliefs, dome pistons, lower octane fuel or a smaller cam. I haven't decided what route I'm taking; I'm considering a smaller cam. The engine needs to come apart for a rebuild because of the number of runs on it; I'll make the changes to get the cylinder pressure up at that time.

Opinions?

I selected all of the components for the 355 in this division four super gas car. It’s running AFR 210 heads with 58cc chambers, the only modification done to the heads are the grooves. With a small dome the compression is near 13:1, the cam specs are below.

With a glide and a 4:88 gear the car runs 9.30s at 142, 60fts in the 1.2s


Bullet Racing Cams
Grind CHS 292/298-06R
Duration @ 0.050" 262/268
Lobe lift 0.430"/0.430"
Separation 106

Attacking me get's you no where. Unless you can debate with me with respect, I choose not too.

Tellling me you can control testing with outside weather influences is ignorant.(No, I didn't call you stupid, I said you were misinformed) No one can. It's just that simple.

I'll give you a list,

Most Race gas sold at tracks has proven multiple times to be inconsistant unless a top name brand. VP or the like. Staging lane temps, track temps near the lights, engine temp, oil temp, winds, barometric pressure, Reletive humidity, sun exposure, timing if not locked, No of runs on a engine(perhaps not so much in drag racing though) Your body weight, Fuel load, Chassis flex, No. of runs on the track prior to your run(amount of rubber laid), and track condition are all things that are hard to control. Some are harder than others. Some are impossible. All will affect you result's even on a average of several thousand runs. An engine dyno is the best and most accurate way for all these variables are either eliminated or controlled.

I don't see a problem with you continuing testing. I thinks it's a valid idea as long as the edges don't become embers. You never said what your compression ratios are, I would think going to 16 or 17:1 would give more light to your testing.

I'm not attacking you, I trying to tell you that you don't appear to understand detonation or how I test engine detonations limitations. Before you can determine the accuracy of what I’m doing, you first need to fully understand it, no assumptions.

If you would like a respectful debate, I'm up for it.

Let’s go back to quench piston’s idea of testing detonation on a steep hill. To minimize variables we will test the same exact 10.2:1 compression engine/car with two different fuels.

Test 1… 92 octane premium

Running premium we set the air/fuel ratio and timing running up the hill. The car is pulling strong with 38 degrees total advance.

Test 2 …87 octane regular

Same day we drain the tank and filled it with 87 octane regular. Running up the hill the engine rattles like a tin can full of rocks. We retard the timing until the rattle goes away. The rattles gone with 30 degrees total advance, power is down but the engine runs good.

Results:
Eliminating most variables we tested detonation limits using a hill. We now know we need premium fuel for full performance with the combination at hand.

1, Oh brother switching from thongs to briefs would cure this, men should not wear thongs lol.

2, Any drag racer worth his weight tunes according to weather conditions and factors in weather conditions into the ET/MPH. I don't see where he says he does or does not do this. Find where he said this so I can check it out too.

3, Even dyno cells have variables. Where is the air temperature sensor located, is it against a wall that is getting heated by the sun in the afternoon or is it in a shadow in the afternoon? Are all the variables automatically factored in on one particular dyno or is it manually entered. Did the dyno operator hit a 5 or a 2, 4, 8, or 6 on the key pad? Is it a Eddy current or a water brake dyno? What is controlling the temperature of the water in the water brake dyno? Is it in the shade or sun during the day?

4, They, both dyno and drag strip use correction factors. What if the engine block you are using on the dyno has low nickel content and the bores are doing a snake dance? If he is adding power wouldn't the chassis flex more and not give him the true indication of his progress? Maybe he is progressing more than he knows. All I am saying is that if a drag strip is all he has to work with then thats all he has and there is no sense in telling him his reduced ET's and increased MPH are worthless. Thats like saying the winner of a NASCAR race who won by .05 seconds is really not the winner because the second place guy's engine dynoed at 10 more HP. I never seen a dyno win a race on a race track, cars with engines in them race and win on the track.

Thats how we did it here where I live since access to a hill was easier since no one had a dyno in our area for decades. Now there is one but then again, whats cheaper, $60/hour for the dyno or a stop watch and a hill. Perhaps I would baseline my car against another car, make a change and race against the same car again up the hill to see if I beat him or not. After all, its who takes the checkered flag in the end, thats what it all boils down to. Some guys can put a combo together and hit the dirk track and make guys who have 40 dyno pulls worth of testing on their engines look dumb founded. That would make a good idea for a new class of racing, grass roots non dyno tested engine racing. YeeeeeeHawwwwwwww!

I predict that in about 5 years this idea will be one of those that seemed like a good one at the time but didn't end up being near as good as was hyped.

tom

Tom,

Carve up a set and let us know what you think.

Quench Piston,

The test equipment available today is great, advancements are made daily because of the top level people and their ability to use the tools available to them to accomplish what seemed to be imposable just a few years ago.

Never the less I get a thrill when I’m able to pull a set of heads and with small improvements to VE and combustion see the same engine running way faster than ever before. That’s what makes hot rodding so great, if you can afford a car you can play. Way to often people spend more money than needed to accomplish their goals.

There is a lot of truth in that statement Tom. I can't remember all of the "trick of the month" things I have seen in my career. I'm not weighing in one way or the other on this subject until I have more personal experience and have seen more evidence from both sides.

Barry

Now here's a logical person. "Personal experience" combined with evidence from respected people. If we get to a point where the people you respect most have positive comments, and then combine that with personal involvement. Then you can give an honest opinion.

Kind of like how fuel injection is main stream now used by every auto manufacture. Kind of like the lean burn. Oh yea, lets not forget about fast burn either with the fabled vortec head. Yep, it will die someday.

Actually, Einstein, I was thinking more along the lines of water injection, the original twisted wedge SBC heads, CB radios.......

Oh, and yeah, the original Chrysler lean burn was a real success........

tom

Sure made the 2.2 a success and helped make the K car a real success. Point is even though lean burn didn't work as intended it set the automotive world on its ear for others to wake up and take notice and follow. Something the Army teaches is that you crawl, walk, and then run. Some of us expect to be born running, it don't happen. Oh shooooooooooooot now you done it, do you know the story of the old bull and the young bull? Pleas tell me you do because I tell it very poorly but still get the point across.
Nearly 1 million K cars were sold in 9 years? Must have been something good about them and lean burn.