Some dyno testing you guys may want to follow on YouTube

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It’s interesting just to see what each one will make, but they are not a direct comparison. And it’s definitely not an A to B test of cylinder heads.
 
Most don't have dyno's got to take what you can get.
 
I finally edited this post at the very beginning so it wasn’t as confusing. Trying to do three things at once is to much for me anymore. Lol
 
Newbomb Turk said:
Even if the information is skewed? I’m all for testing, but bad testing ends up with bad results.
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Well you got to take the results with a gain of salt, but if you keep on see X head and Y head make a certain amount of hp with similar general parts, think it’s safe to say if you build similar your gonna get similar results.
 
273 said:
Well you got to take the results with a gain of salt, but if you keep on see X head and Y head make a certain amount of hp with similar general parts, think it’s safe to say if you build similar your gonna get similar results.
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That’s assuming they are building the engines right. Most guys don’t use near enough compression. And they don’t tune well.

As you add up the errors it becomes obvious testing and doing it correctly costs a huge amount of money and takes time.

Not all testing is good testing.
 
Newbomb Turk said:
That’s assuming they are building the engines right. Most guys don’t use near enough compression. And they don’t tune well.

As you add up the errors it becomes obvious testing and doing it correctly costs a huge amount of money and takes time.

Not all testing is good testing.
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Just a quick dyno question I have for some dyno results and I wish I knew the manufacturer of the drive on dyno but I Dont. If a test was done and he came up with let’s say 580 horsepower how many horsepower would this be on an engine dyno.
 
pittsburghracer said:
Just a quick dyno question I have for some dyno results and I wish I knew the manufacturer of the drive on dyno but I Dont. If a test was done and he came up with let’s say 580 horsepower how many horsepower would this be on an engine dyno.
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It depends on friction losses in the drive train.

A power glide is generally about 18%. Most 3 speeds are 20%. Sticks are slightly less than a PG as a general rule.

So the 580 with a PG would be 690ish.

I was looking at Boosted’s numbers and his converter is so loose you can’t get a pull on it.

On my dyno I try to get the pulls 8-10 seconds long. You get more data that way, but it skews the numbers a bit higher doing that.

We built a dyno car at the last shop I worked at. We bought adapters for every engine as they came through the shop.

We had a PG and a very tight converter so we could load the engine long enough to get good, useable data.

I doubt Boosted’s engine is actually making peak torque at 5700 rpm. He is way short on cam to get peak torque that high.

The only way to know for sure is to get it on a crank dyno and see what you get.
 
Newbomb Turk said:
That’s assuming they are building the engines right. Most guys don’t use near enough compression. And they don’t tune well.

As you add up the errors it becomes obvious testing and doing it correctly costs a huge amount of money and takes time.

Not all testing is good testing.
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True, but the alternative is random voices on the internet and or your local Uncle Tony for most.
 
Newbomb Turk said:
It depends on friction losses in the drive train.

A power glide is generally about 18%. Most 3 speeds are 20%. Sticks are slightly less than a PG as a general rule.

So the 580 with a PG would be 690ish.

I was looking at Boosted’s numbers and his converter is so loose you can’t get a pull on it.

On my dyno I try to get the pulls 8-10 seconds long. You get more data that way, but it skews the numbers a bit higher doing that.

We built a dyno car at the last shop I worked at. We bought adapters for every engine as they came through the shop.

We had a PG and a very tight converter so we could load the engine long enough to get good, useable data.

I doubt Boosted’s engine is actually making peak torque at 5700 rpm. He is way short on cam to get peak torque that high.

The only way to know for sure is to get it on a crank dyno and see what you get.
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Thanks. My buddy switch from a 440 stroker to an LS 3 (LS engine). Factory LS3 heads ported will flow at least 370cfm. It’s a 440 cubic inch engine with I think cnc’d aftermarket LS3 heads. Powerglide car and lighter than me he finally hit on the right converter after my son and him tried I think six of them. He’s .10-.15 quicker than I was last year so he had the engine redone.
 
pittsburghracer said:
You know as much as I do. I only saw this posted on Facebook and know you guys enjoy this stuff. I won’t be following along.
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I'm willing to bet you'll be here when the results are in and this thread that you started is 14 pages deep. Why wouldn't you want to maybe take a little info away from it if you could? J.Rob
 
Newbomb Turk said:
You won’t learn much testing like that. Comparing cylinder heads on different short blocks makes zero sense.

The correct way to do it is put the heads on the same short block.

Anything else just tells you one engine made different power than another. You can’t compare the heads.
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Bombastic as usual YR, This isn't about settling some internet debate once and for all. I think this is interesting and look forward to it--nothing more, nothing less. I just hope the dyno shop has a solid testing methodology and well maintained equipment. J.R.
 
pittsburghracer said:
I’ve ran a lot of blocks that weren’t squared or cut for a long long time. Each and every combo was in the hole. I hear the word quench thrown around a lot but in the case of my sons 360. The pistons were flat tops well in the hole, felpro 1008 head gasket, open chamber 340 style Edelbrock heads, and it ran 10.30’s@3200 pounds. So I guess sometimes something that shouldn’t work by the book, works. Would I lose sleep over .012????? Hell no.
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.012" makes a measurable and noticeable difference-I'd say you were missing out. J.R.
 
pittsburghracer said:
I’m going to add on more thing here. I would probably have the 1-2-7-8 pistons in to see if it was worse than .012 deck height checking square. Then make a decision. Just to make sure.
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That's the long way, did it that way about 5 times in 1995 and said to myself "There has to be a better way" --Get yourself some 12" vernier calipers and this can be done in about 5 minutes. Accurate to within .001". J.Rob
 
273 said:
Well you got to take the results with a gain of salt, but if you keep on see X head and Y head make a certain amount of hp with similar general parts, think it’s safe to say if you build similar your gonna get similar results.
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Absolutely agree--Its the testing methodology and S.O.P. that could undermine the results. J.Rob
 
RAMM said:
That's the long way, did it that way about 5 times in 1995 and said to myself "There has to be a better way" --Get yourself some 12" vernier calipers and this can be done in about 5 minutes. Accurate to within .001". J.Rob
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I figured the machine shops had to have an easier way. Thanks.
 
RAMM said:
That's the long way, did it that way about 5 times in 1995 and said to myself "There has to be a better way" --Get yourself some 12" vernier calipers and this can be done in about 5 minutes. Accurate to within .001". J.Rob
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Curiosity got me and I had five minutes so I did some reading. Does this sound right??? If so I’ll save it.

Deck Height · Help Center
 
I could see if you were searching for 5-20 more hp especially for a highly competitive race class that the result won't be good enough to go one way or another, but for a general build it will show what's possible with each and if there in the same ballpark which I doubt the cnc SM are but guess we'll see.
 
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pittsburghracer said:
Curiosity got me and I had five minutes so I did some reading. Does this sound right??? If so I’ll save it.

Deck Height · Help Center
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That’s how I’ve done it, albeit I just use the upper jaws on the caliper rather than my bore gauge for the main journal measurement…just quicker. The fun part is trying to get the lower jaws on the caliper to sit flat on the deck (others who do this more often are probably more efficient). Careful when dropping the jaws down the bore, the jaws (at least on mine) are pretty long and those upper jaws look like they want to leave their mark in that nice new cross hatch.
 
RAMM said:
Bombastic as usual YR, This isn't about settling some internet debate once and for all. I think this is interesting and look forward to it--nothing more, nothing less. I just hope the dyno shop has a solid testing methodology and well maintained equipment. J.R.
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How is pointing out the facts bombastic? Do you test like that? It’s a poor test.

But you know that.
 
I agree with RAMM in that I’d be way more concerned with differences related to testing procedures and weather variables than whatever small power differences are the results of the slight change to the short block configuration.

Stroker #1 goes to Darrell Watters dyno on April 27, and stroker #2 goes May 4. This should be a fairly close comparison of the heads.
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I agree, and feel like I’d be able to extrapolate some useful info from the results.

I don’t see any claims that this test is intended to be the last word in how the heads compare.
 
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