Super Stock Dyno Pull

[vortecpro]

I can tell you testing on my dyno SF 901 a 30 pound flywheel shows about 6 corrected HP less than a flex plate @ 600 RPM per sec, on a typical BBC. I have tested @ less than 200 RPM per sec many years ago, and if I remember right it showed more HP than 600 per sec, but not 1 percent more in my testing.

[SpeierRacingHeads]

Yea, I have way more things to worry about and dyno power isn't on the list right now. This car has 10 runs on it since built new. So if I want a challenge, I found it!

As far as this dyno. It doesn't use a flywheel and they go 1-12 on rates. We tried 3, 6, 9, 12, just to see. Honestly maybe 3 hp. I think the difference in the dynos comes in the software. However, I know it's lower than the new SF in town because they/we have had customers do that.

And like Mark, I told myself before I went if it made X power I was happy. It came within 5 of that. Then I get home and hear all these huge numbers and me being me, think I did a poor job. lol.

[RW TECH]

I don't blame you. All someone has to do is make 600 RPM/SEC or faster sweep rate pulls & let SF software add their calculated inertia and you will wind up with an engine that looks about 3.5%-5% better than it actually is. Slow the sweep rate down to 300 RPM/SEC or slower and all of a sudden the inertia added vs no inertia numbers line up closer to each other by a bunch.

This is how people get sucked into advertised HP numbers on engines for sale (i.e.-crate specials).

I've never seen a 1 percent difference between 300 RPM per sec to 600 RPM per sec on my SF 901 with wyn dyn, much less a 3-5 percent swing. I did test recently on a PowerMark dyno, with no inertia factor a 645 HP engine made around 600 with no inertia factor, and this was with a 30 pound flywheel turning a driveshaft that was not inline with the brake.

I've tested on different dyno's, and generally the operator will ask me what kind of power I expect to make, I always say it will be over a certain number, I'am then told "this dyno" is stingy in so many words, my comment to that is: yea I never seen a dyno owner not say that. Infact the last independently owned dyno I tested on the owner is frequently on this forum, feel free to comment-

Chad

Were going to know what kind of power it makes when you get to the track. I have raced for years in the same area you have near you, those horrible conditions will be taken into account.

I find this interesting. If I may Id like to frame this differently.

Let’s say we pick an arbitrary RPM/sec of 300, and make some tests with a 30 pound flywheel attached. Then test at 600 RPM/sec. Then do it again with an 11 pound flywheel. Shouldn’t the faster acceleration rate show less power with the heavy flywheel?

Now take that same engine and test it on a true inertia dyno, like the dyno Mike Laws developed. It’s now called the Revolution dyno. On that type of dyno the engine accelerates a know load at whatever RPM/sec the engine is capable of. I would think that the addition of flywheel weight, crank weight or any other rotating weight would and should affect the ability of an engine to accelerate.

Am I thinking wrong here?

You're not thinking wrong. If you want to see the highest possible number that is "real" you can hold the engine at an RPM point and you will see more than you will at the same RPM point in a sweep.

[RW TECH]

The dyno I use is low vs some of the others. Last time I posted a sheet from it from another one of my personal engines I was told it was bad, so I'm not posting a sheet. I'm going to put it in the car and test the wheels off it. Then freshen it and change a few things. Like the cam, IMO it's all wrong and I knew/know better so I'm putting in what I want.

I don't blame you. All someone has to do is make 600 RPM/SEC or faster sweep rate pulls & let SF software add their calculated inertia and you will wind up with an engine that looks about 3.5%-5% better than it actually is. Slow the sweep rate down to 300 RPM/SEC or slower and all of a sudden the inertia added vs no inertia numbers line up closer to each other by a bunch.

This is how people get sucked into advertised HP numbers on engines for sale (i.e.-crate specials).

I've never seen a 1 percent difference between 300 RPM per sec to 600 RPM per sec on my SF 901 with wyn dyn, much less a 3-5 percent swing. I did test recently on a PowerMark dyno, with no inertia factor a 645 HP engine made around 600 with no inertia factor, and this was with a 30 pound flywheel turning a driveshaft that was not inline with the brake.

I've tested on different dyno's, and generally the operator will ask me what kind of power I expect to make, I always say it will be over a certain number, I'am then told "this dyno" is stingy in so many words, my comment to that is: yea I never seen a dyno owner not say that. Infact the last independently owned dyno I tested on the owner is frequently on this forum, feel free to comment-

Chad

Were going to know what kind of power it makes when you get to the track. I have raced for years in the same area you have near you, those horrible conditions will be taken into account.

Is this with inertia added in both cases, or without? Without inertia I also have never seen a 3.5%-5% difference but I have seen the 3.5%-5% difference more times than I can count with the added inertia.

I usually disregard any added inertia in the water brakes unless low to peak then peak to low sweeps were made and adjustments made to make those two show same values, or if on an electric brake (AVL) a non-firing motoring test to determine actual inertia & frictional loss on a given engine. Mostly I just ignore the added fluff & work with obs HP * CF, and typically run 200 RPM/SEC or 300 RPM/SEC sweeps.

[Stan Weiss]

Higher HP / Lower HP those tests are not what the engine sees on the drag strip. It is more of a fixed load variable acceleration rate deal much like what Mike Laws dyno did.

Stan

[skinny z]

The type of dyno used and the measuring methods notwithstanding, would the HP and TQ peak RPMs be the same?

A chassis dyno is all I have experience with and I take the results as basically a point of conversation. But the RPM peaks I feel have some real value.

[vortecpro]

Yea, I have way more things to worry about and dyno power isn't on the list right now. This car has 10 runs on it since built new. So if I want a challenge, I found it!

As far as this dyno. It doesn't use a flywheel and they go 1-12 on rates. We tried 3, 6, 9, 12, just to see. Honestly maybe 3 hp. I think the difference in the dynos comes in the software. However, I know it's lower than the new SF in town because they/we have had customers do that.

And like Mark, I told myself before I went if it made X power I was happy. It came within 5 of that. Then I get home and hear all these huge numbers and me being me, think I did a poor job. lol.

That LT1 has to be a different animal than a 295/350 combination, more compression, bigger valves, different carb. All you have to do is take the observed HP average and do the math it will at least run that at Great Bend.

[hoffman900]

Higher HP / Lower HP those tests are not what the engine sees on the drag strip. It is more of a fixed load variable acceleration rate deal much like what Mike Laws dyno did.

Stan

The AVL dynos are the best. Honda has a good paper on what they did with their Indy Car engine converted to IMSA / LeMans use. Did some sweeps at 3000rpm/s, and then evaluated port shapes by holding the engine steady at full throttle and “dumping” the clutch to record sweep time

[nhrastocker]

Some of the fastest and most powerful SBC Super Stock engines in the country are built by John Gulius.
You pay a premium for his engines, but they are very fast and competitive.
However, he never gives out a dyno sheet or numbers no matter what you are paying and it is part of the deal.
John will assist the customer in determining the right converter stall and lockup and engine RPM ranges.
He is the epitome of "You do not race dynos".
Now that John has joined forces with Gale Powley, they are really cooking some power...still, you don't get a dyno sheet...

[SpeierRacingHeads]

Some of the fastest and most powerful SBC Super Stock engines in the country are built by John Gulius.
You pay a premium for his engines, but they are very fast and competitive.
However, he never gives out a dyno sheet or numbers no matter what you are paying and it is part of the deal.
John will assist the customer in determining the right converter stall and lockup and engine RPM ranges.
He is the epitome of "You do not race dynos".
Now that John has joined forces with Gale Powley, they are really cooking some power...still, you don't get a dyno sheet...

Nor should they. Dynos sheets are over rated. Engine peaks at 5400 and 7400 on power and they leave the starting line at 6500 and traps at 8800...lol

You can only imagine the ration of SHYT I have received for no sheet. From it must be junk to who cares. When a man works as hard as most do on this stuff, it's their choice. I have already showed 75% more than anyone else would. HA!

[RW TECH]

Some of the fastest and most powerful SBC Super Stock engines in the country are built by John Gulius.
You pay a premium for his engines, but they are very fast and competitive.
However, he never gives out a dyno sheet or numbers no matter what you are paying and it is part of the deal.
John will assist the customer in determining the right converter stall and lockup and engine RPM ranges.
He is the epitome of "You do not race dynos".
Now that John has joined forces with Gale Powley, they are really cooking some power...still, you don't get a dyno sheet...

Gale is very, very sharp and he taught a lot of standout people along the way too.

[ClassAct]

Higher HP / Lower HP those tests are not what the engine sees on the drag strip. It is more of a fixed load variable acceleration rate deal much like what Mike Laws dyno did.

Stan

The AVL dynos are the best. Honda has a good paper on what they did with their Indy Car engine converted to IMSA / LeMans use. Did some sweeps at 3000rpm/s, and then evaluated port shapes by holding the engine steady at full throttle and “dumping” the clutch to record sweep time

Ok, most of it will go over my head but do you have a link to that paper. I’d like to read it.

[bob460]

Some of the fastest and most powerful SBC Super Stock engines in the country are built by John Gulius.
You pay a premium for his engines, but they are very fast and competitive.
However, he never gives out a dyno sheet or numbers no matter what you are paying and it is part of the deal.
John will assist the customer in determining the right converter stall and lockup and engine RPM ranges.
He is the epitome of "You do not race dynos".
Now that John has joined forces with Gale Powley, they are really cooking some power...still, you don't get a dyno sheet...

Gale is very, very sharp and he taught a lot of standout people along the way too.

Also had a hand in the design of the Aussie Higgins cleveland & Sb2 heads and intakes......sharp dude for sure!

[RW TECH]

Gale is very, very sharp and he taught a lot of standout people along the way too.

Also had a hand in the design of the Aussie Higgins cleveland & Sb2 heads and intakes......sharp dude for sure!

Gale has had a hand in a lot of things that are exceptional. One of the best kept secrets in the developmental side of racing engines, especially heads & manifolds.

[nhrastocker]

Also had a hand in the design of the Aussie Higgins cleveland & Sb2 heads and intakes......sharp dude for sure!

Gale has had a hand in a lot of things that are exceptional. One of the best kept secrets in the developmental side of racing engines, especially heads & manifolds.

You are correct Rob. He developed a new Super Stock SBC TPI EFI intake manifold that is a game-changer.