286 Dyno Results

[frnkeore]

First this isn't my engine. I stumbled across it yesterday.

Since there are very few dyno results for these engines, I thought I would post this to show what even a high end build might produce.

[Ronnieroadster]

It would be nice to see the engine pulled to 6500 but considering the Chinese crank and rods it may not hold together.
Ronnieroadster

[rockfla]

Ronnieroadster


Question from a complete Flathead High Performance dunce......Given the build specifications and the numbers of the above listed pull......Wouldn't a 6500 pull continue to show a drop in both HP and torque numbers????? OR torque at least????


I can understand maybe building more HP to a point but even at some point wouldn't that start to fall as well torque?

[Ronnieroadster]

Originally Posted by rockfla

Ronnieroadster


Question from a complete Flathead High Performance dunce......Given the build specifications and the numbers of the above listed pull......Wouldn't a 6500 pull continue to show a drop in both HP and torque numbers????? OR torque at least????


I can understand maybe building more HP to a point but even at some point wouldn't that start to fall as well torque?

The torque will continue to fall that's to be expected. But looking at the results the Horsepower is still climbing where it begins to fall off at this point is unknown. I would guess in the area of 5200 but we may never know. Seeing the results at 199 HP tells me there would be the potential for over 200 HP which would be extremely good for the builds combination. Torque helps get the mass underway but the horsepower as well as RPM is what gives the speed.
Ronnieroadster

[Ol' Ron]

This is an excellent power output for a flathead. would be nice to know what modifications were made to it. Hard to get that much air into a normally asperated flathead.
Gramps

[Bored&Stroked]

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And then there is the classic question of "On whose dyno?". There are quite a few engine dyno results that are a bit "optimistic" as far as the numbers output. This is particularly true when the dyno belongs to the shop that built the engine.

Some of this is due to the fact that a customer never complains that the "HP is TOO darn high!" - bigger numbers make customers happy. LOL

[frnkeore]

This was a high end build, with bigger valves and nice port work. It was also relieved but, I don't think that does much but, reduce compression and compression is very hard to get!!

I've only seen one flow bench result for port work, on these engines and that gave a intake flow of 150 cfm. Not much but, should be good for up to 225 hp. 150 cfm can get you 300 hp on a OHV engine.

I didn't care for the LSA & ICL on the cam. I think 111-110 would have been better with the ICL at 108-107 or so.

I would have really like to have seen it with a 400 Jr cam, with 244° @ .050.

The other thing is, that I think it was over carbed, with those three, 200 cfm carbs. Has anyone used those 98 Demon carbs? They are a very modern carb, they look like a side hung Holley bowl on a very modern 2 bbl body. I'd never seen them before.

[frnkeore]

Speaking of cams and compression, how many are aware of the Dynamic Compression Ratio (DCR)?

It is the actual compression that the engine sees, when the intake valve closes, on the compression stroke. The intake valve center line (ICL) plays a key roll in that.

To give you a idea of what that can do for compression, I did some calculations.

Cam in the above engine, has a intake valve closing of 67° after BDC and if it had a CR of 8.52, it would have a DCR of 6.69

If we swapped out that cam, for the 400 JR and it's 60° intake valve close ABDC and with the same CR, it would have a DCR of 7.05, set straight up and if it was advanced 3° to 57° ABDC, it would increase to 7.19, gaining .5 DCR over the dyno cam.

That is one of the ways that you can pick up HP, with a low reving engine.

[JWL]

I agree the LSA is much too wide for maximum, unblown, power but would probably work well with a blower. The wot vacuum is not listed which would help determine carb sizing issues but I do not believe that is a problem. There is an over rich condition throughout that pull which likely aided the lower speed torque but hindered at higher revs especially above 3500. Still, those power numbers are very good. And, as has already been explained, it sorta depends on which dyno and which correction factors.

A intake port flow of 150 CFM@28" and at .400 lift is a very well done port.

[Frank Miller]

I have never seen dynamic compression discussed here but it does play a big part in being able to run cams with a lot of overlap by upping the compression. As you said compression is hard to come by in a flathead but it is a big factor in an overhead.

Originally Posted by frnkeore

Speaking of cams and compression, how many are aware of the Dynamic Compression Ratio (DCR)?

It is the actual compression that the engine sees, when the intake valve closes, on the compression stroke. The intake valve center line (ICL) plays a key roll in that.

To give you a idea of what that can do for compression, I did some calculations.

Cam in the above engine, has a intake valve closing of 67° after BDC and if it had a CR of 8.52, it would have a DCR of 6.69

If we swapped out that cam, for the 400 JR and it's 60° intake valve close ABDC and with the same CR, it would have a DCR of 7.05, set straight up and if it was advanced 3° to 57° ABDC, it would increase to 7.19, gaining .5 DCR over the dyno cam.

That is one of the ways that you can pick up HP, with a low reving engine.