Engine and Transmission Tech

> For the record, are we discussing ID. or OD. on tubing sizes?

The data is for ID. Headers vary in their wall thickness with street headers
typically having thicker walls compared to race headers.

> Any solid data on merge collectors?

I've not personally tested them yet but will likely in the future on
mid-length Pantera 351C headers. However, a SBF racer I know has installed
them on both his car and his son's (both record holders) and gone faster.

> Stepped primary headers, properly built, function similar to anti reversion
> cones?

Stepped headers approximate a constant taper angle. I'm not sure if the
abrupt area changes have an effect on reversion or not. If so, the mechanism
would be different (via finite amplitude waves).

> Good info Dan, about the hp/rpm losses and the area under the curve. I have
> long been a believer in chasing that volume vs. absolute hp peak so to me
> this is very revealing (and to be honest, 5-10 hp loss sounded like
> pie-in-the-sky).

Agreed. Peak numbers are irrelevant. The area under the curve in your
desired operating range (between shift points) is what really matters.

> About the anti-reversion cones, I looked at some test results (Harley) and
> the graphs I saw showed no gain and an upper end loss due to restriction.
> These were slip-in cones that are simply inserted into the end of the header
> pipe. Starting to sound like snake oil, and I'm suspecting that any advantage
> is going to be in a very specific application under ideal conditions (racing
> perhaps).

On a two plane crank V8 with bank separated 4-into-1 headers, Vizard's
testing indicated the AR effect required a cross-over to work. That
testing used cones in the header flange.

> All of this leads me to suspect that a properly designed set of headers is
> not going to have much of an issue with reversion and therefore the cones
> will be of little benefit.

Reversion is more of an effect of the cam overlap, particularly the component
provided by narrow lobe separation angles. Reversion occurs at lower RPM,
so don't expect to see any benefit at higher RPM. Vizard's testing showed
the largest effect occurred at low RPM and trailed off as RPM increased.
He presents before and after testing in both "Performance with Economy" and
"How to Build Horsepower, Volume 1". BTW, Vizard has a new version of "How
to Build Horsepower" coming out. The second edition appears to replace
Volume 1 (an overview that covers everything). Volume 2 covers induction
(carbs and intake manifolds).

Dan Jones

>Jim, have you read The High Speed Internal Combustion Engine by Sir Harry R. Ricardo?
>Funded to develop piston engines for the war effort, Ricardo did so without any
>regard to class rules. His work is at the base of everything hot rodders do, whether
>they realize it or not.

>Dan Jones

I'm not sure if you realize it Dan, but this book costs ~$350.00, not the sort of thing the average guy just goes out and buys. My local library is trying for an intra-library loan but I'm not holding my breath.

But I did run across a Vizard book in my personal library and will look it over again during thanksgiving.
Happy Turkey Day all. Let's not forget how we got here.

JB

"Happy Turkey Day all. Let's not forget how we got here. "

The Pilgrims could have got here faster if they had stuck a V8 in the Mayflower!

>I 'm not sure if you realize it Dan, but this book costs ~$350.00, not the sort of thing the average
>guy just goes out and buys. My local library is trying for an intra-library loan but I'm not holding my breath.

Oh come on. There's a bunch of used ones on Amazon for as little as $250. !! :)

Martin

Reportedly, the Pilgrims had a"Ford" in their fleet,(Pinto). Is that why it tookem soo long ? Perhaps "Sir Harry" charges soo much, posthostumously, is because his brother,"Ricky", got all the Press ? lol. and Happy Pilgrim Day.roverman.



Edited 1 time(s). Last edit at 11/25/2010 03:05PM by roverman.

Dan,

Did I read somewhere above that your expecting 350 BHP from your 4.2, I built a stroked 3.9 with 4.2 crank, 5.85" Chevy rods and flat top with cut outs 305 Hypereutectic KB pistons to give 4350cc.

I have modded alloy 300 heads with 1.63" In and 1.4" Ex. with the seats taken out to actual seat size and the throats and bowls all blended to match, port runners are left as standard with a minor clean up as specifically for road use.
Static comp ratio a bit lower than I would have liked at approx 9.4/1

Induction system is currently Edelbrock 500 and manifold and exhaust is a RV8 through the inner wings system with single pipe.

Cam is Crower 50232

Ignition is a recurved lucas 35DLM8

Haven't had it dynoed as the result from rolling roads seem to vary wildly, what would you think it should produce, I was aiming for 260+ BHP.

Regards,

Kevin Jackson.

Hey Jim,

Ricardo's book is available to read on line.
It's been a while and I was never able to print it but I'll try and find the address again for you.

Cheers
Fred

Thanks Fred, I'd like to see that. It turns out my library was able to get it for me and I've had a few days now to read it. A wealth of information there. I particularly liked this passage:

“…the finest achievement ever reached in any sphere of mechanical engineering, for it constitutes the best example of what can be accomplished by the co-operation of the scientist and the practical engineer working together in harmony. In every successful example it will be found that the actual designer of such an engine is neither a great scientist nor an expert mechanic, but an artist with an artist’s temperament and intuitive genius, though none the less ready to appreciate and accept all the aid that the scientist and the practical mechanic can give him, and competent to blend his and their conflicting demands into a perfect picture. Such men are rare and in any one country can be counted on the fingers of one hand. Without doubt the greatest of them was Sir Henry Royce.”
Sir Harry R. Ricardo: The High Speed Internal Combustion Engine pp. 280-282 (5th edition reprinted 1972)

To that I'd like to add a quote of my own:
"Aim high. You may fail miserably, but you will also know moments of true greatness. For this there is no substitute."

JB

> Did I read somewhere above that your expecting 350 BHP from your 4.2

Using the flow numbers from my GM race heads, Dynomation predicts between
323 and 359 HP, depending upon how efficient the single plane intake is.
The GM race heads were designed for Mickey Thompson's Indy car effort and
Lance Reventlow's mid engine Scarab. Compared to my ported Buick 300 heads,
they GM race heads are better on the exhaust but worse on the intake due
to the smaller intake valve size. On the flow bench, the exhaust flows
173 CFM at peak compared to an unported Rover flow of 92 CFM. Because of
the strong exhaust port, a custom cam was required to match the flow
characteristics to maximize the horsepower.

> I built a stroked 3.9 with 4.2 crank, 5.85" Chevy rods and flat top with
> cut outs 305 Hypereutectic KB pistons to give 4350cc. I have modded alloy
> 300 heads with 1.63" In and 1.4" Ex. with the seats taken out to actual
> seat size and the throats and bowls all blended to match, port runners
> are left as standard with a minor clean up as specifically for road use.
> Static comp ratio a bit lower than I would have liked at approx 9.4/1
> Induction system is currently Edelbrock 500 and manifold and exhaust is
> a RV8 through the inner wings system with single pipe.
> Cam is Crower 50232
> Ignition is a recurved lucas 35DLM8

Entered into Dynomation.

> Haven't had it dynoed as the result from rolling roads seem to vary wildly,
> what would you think it should produce, I was aiming for 260+ BHP.

With my ported Buick 300 heads with Stage 1 Buick V6 valves, the prediction
is 279 HP. With unported Buick 300 heads and standard valves, the prediction
is 232 HP. Unported Buick 300 flow numbers but your valve size, the prediction
is 238 HP. Adjusting the throat sizes gets 242 HP. Your flow numbers would
be somewhere between these two, figure something between 240 and 280 HP,
so your 260 HP guess is in the ballpark. These use the dimensions of the
Performer Rover dual plane intake and an assumption that is "standard flow".
If the intake assumption is "high flow", expect 15 additional HP. If you have
space for a plenum spacer, that would help the intake rating and increase the
peak power. I'd need your actual cylinder flow numbers and min/max port sizes
to be more accurate.

Dan Jones

Hey Jim,

So here you go.
www.scribd.com/doc/40610101/The-High-Speed-Internal-Combustion-Engine-by-Sir-Harry-Ricardo

It just boggles my mind that one man could have such a firm understanding of all these principles so long ago.
90 years on, with countless hours spent by countless people, and no one person understands these principles any more completely than he did.

Cheers
Fred

Thanks Fred. He was impressive no doubt. Since that is the 2nd edition it will be interesting to see what he changed between that and the 5th edition. Some 40 odd years was bound to have made a difference.

JB

Thanks Dan.

Yes forgot you were using those specially cast heads.

Kevin

Ok, Most will accept that 4 into 1 merge collectors, add power. What about a "gullet" in center of the 4 pipes,inside the collector ? Old skool therom of up to 10 hp gain for conventional 4 into 1 collectors,(2). roverman.

To Dan Jones:

I sent you a PM in regard to this thread last night... Hope you are still watching and can reply.

In the meantime, thank you again for all your valuable guidance!

Cheers,

Mark Griffin