Engine Buyers Heads Up!!!

[CSX 4027]

In helping one of my freinds power up his CSX car he recently purchased, I have been helping him with the chore of finding a legit 427 engine builder who can supply him with an HONEST product making Honest Horsepower at an Honest price. What have I found so far? A lot of nonsense. I have seen Dyno sheets to vomit from with distorted numbers. If you are not an engine maven and you are going to plunk down big dollars from the guy with the highest number claims then, do your homework and learn to read a Dyno sheet and ask a lot of questions. Remember a Dynomometer is a calibrated machine that can be toyed with in order to lure unsuspecting prey.

[Turk]

Steve,
Thanks. I have been wondering about that myself.
Admittedly my engine knowledge is limited and I am not very good with mechanical things.

I often wondered, how does one builder take a block and put in similarly ported heads and a a crank. With given pistons and cams from a limited number of suppliers builds an engine that puts out 715 HP, and builder B takes the same components , all he can claim is 500 HP from the same combination of parts?


This is assuming similar compression and similar parts.
Is one not telling the truth, or is there that much of a variation in the skills of the builder. What magic dust is being sprinkled?
Can it be the gas?

TURK

[CSX 4027]

Now you understand vomit.

Look at it this way. My last motor was a powerhouse and killed most it was near and at 12.1:1 with all the tricks made 581 HP on a real dyno sheet.

The rest, I'll let you decide. I just saw a street compression sheet well into the mid sixes. The most amazing thing was that the fuel efficiency put it in the most efficient motor on the planet.
Better than any Winston Cup Motor Ever in History.
And if you believe that, I have some swampland I wanna sell you or rather an engine builder wants to sell you!!!

[Turk]

Can I just buy enough for a ranch? Three to four acres is all I need.

How much?

TURK

[ToyCollector]

Steve and TURK, this discourse has been one I have wanted for a long time. For those that have followed my signatures, I think dynos are a bunch of crap as they can be made to read whatever you want them to. I know. That said, if you compare motor runs all in a bogus environment, the readings will all still be relevant to each other. Anyway, I think consumers need to take the bunk #s some vendors are recently displaying and treat them with extreme caution. Do you want a motor that will last, or the one for a few dyno pulls?

[CSX 4027]

Wasn't it the old Abbott & Costello routine where Lou proved the 13 X 7 = 28?
It's the same thing

[Turk]

When I wanted to build my last motor locally, Pat Buckley took me to a very reputable builder (very slow, but reputable).

We talked about this and that, and as soon as I mentioned Dyno, the man told me, he will build me the best engine with the tricks of the trade he knows to work for many years he has been doing this, but couldn't promise HP numbers and wouldn't mess with Dynos.
He said pretty much, if I wanted to put it on a Dyno to find what she'll do, I could go do that after wards on my own.He wasn't interested.

Somehow he sounded believable and convincing.

The other two engines were built by George, and the HP and Dyno figures never came to play.
I am beginning to see a pattern here.
however if you are fine tuning the carbonation etc, wouldn't a dyno come in handy providing you used the same one and the first set of numbers were to establish a base line?

Most Dyno figures I see are not chassis dyno #s, but an engine dyno #s. How useful are those numbers?

TURK

[CSX 4027]

First, I have seen engine builders with real conservative dyno's and no bull.

Second, A dyno is a must!!!! Yes.. It is the cheapest insurance(no sales pitch leenie) for both you and the engine builder that the motor works well.

Also, It is a great tuning tool to get optimum if that's what you want but.......
Ask a builder what was the most he ever got as an increase from the first few baseline pulls to the super tuned tweaked pulls. It ain't 100hp I can assure you. Most times would be hard pressed at 20 to 25.

[CSX 4027]

Another CC member has a thread..
Rate my new dyno sheet!

See if any of the rest of you picked up the problem here......

[Edley Rondinone]

Turk: A couple of posts above, you mentioned "carbonation". What are you making, a "fizzie"? !!! lol !!! (Sorry, I had to comment, I'm still laughing, but with you, of course!)

[RobMcQuarie]

Interesting post Steve. For a lot of guys, the numbers are all important-whether it's dyno numbers or flow numbers. For them, it's always the size that matters, not necessarily the actual performance. (They are the ones that dream of dipping into water when using the urinal).
We dyno most of our engine builds, primarily to performa a proper break-in, determine optimum total timing, tune carburation, set & check valve train, etc. We look at the dyno numbers in relation to what we expected to see, and what we have gotten from other similar combinations.

Our dyno numbers -as well as flow bench numbers- have typically been lower than many of the ones I see passed around. As an engine builder, it sometimes puts me on a bit of the defensive when talking to a customer. I tell them what sort of HP numbers we will expect to see in a certain combination, and they then see advertised numbers that are significantly higher, for similar and often cheaper quoted prices. Sometimes I even question myself as to if we are doing somthing wrong when I see big results from some other well known engine builders. But, then I talk to a few shops around the country that I highly respect, and they are getting similar results, and I feel better again.

True, two builders can take two very similar engine builds with very similar parts and come up with different results, but if the machine work and assembly are both of high caliber, both are decently tuned, the differences will not be that significant. That is not to say you can't find an easy 40-60hp on the dyno. I've seen that when a customer's carb was ill matched to the engine, or when they didn't set up their ignition properly. I always have a say in final carb selection and we set up the distributors on our engines in order to try and avoid those inconsistancies.

Yes, there are a lot of small details and little tricks that can be performed on one specific engine build that will set it apart from another engine using the same parts. Many are for durability and quality. But, the ones done to increase HP, typically only result in small, incrimental power improvements-which is all important in competative racing classes where the racers all fall into a specific power level. But the importance is significantly less for the average street engine.

I tell my customers that the dyno numbers are for general reference, and are not a measure of the "success or failure" of the engine. The proof is in the product as they say. There is SO MUCH MORE to an engine than dyno numbers. The quality, parts combination, and attention to detail are the most important things in my book.

[Turk]

Edley,
Just a clever attempt to pretend I do all my posts without the use of a spellchecker. If I deliberately include an error here and an error there, then people get impressed thinking I write so free of spelling errors, don't even use a spellchecker.

Now if you believe that, I can sell you some of the acerage I just bought from Steve. We won't be using it after all.

TURK

[Jamo]

My engine builder, who's been at it for nearly 40 years and has built everything from Indy winners to AA/Fuelers says the same thing as the engine builders Turk refers to. Tom Kirkham got downright angry with me when I pulled a chassis dyno run. It's as if the REAL ones know better. Yes, a dyno is great for initial startups and tuning--but comparing measurements between motors using different dynos seems to be nearly impossible from reading everyone's opinions over the past few years.

It's like all the horepower gains advertised from different products...add this air filter for a 20% hp increase, this carb for 50%, etc. I added up all the extra length I could gain from the spams--44 feet long and still counting!

[750hp]

Steve, was it only the hp/tq @ 5252 that you were talking about in the other post? The figures are correct in the chart, but it's the first dyno sheet I've ever seen that has the power scale on the left, and torque on the right (with different values...) While it does make it harder to read, at least the values are still matched at 5252rpm.

Other than the weird dyno chart layout, I don't see that the actual power and torque figures shown couldn't be achieved with a well matched 351W combination.

FE figures - to which you're obviously referring to in your initial post - are out of my league entirely. Surely there must be some dyno figure / engine combination / drag racing terminal speeds available. If you know the weight of a car, and it's terminal speed in the 1/4 mile, you're going to have a very good indication of the power being produced. Elapsed times will vary wildly due to traction and other chassis tuning variables, but the mph will always tell a story. So.... any of these "advertised HP" motors been fitted to a Mustang or Fairlane drag car?

Craig

[CSX 4027]

The 351 was very believable in power, just the chart.

[DonC]

In my humble opinion a dyno should be used only for break in and tuning for an engine and/or engine/drive train setup. Comparing dyno numbers from one engine to another is a waste of time if the numbers are from different dynos. As a RELATIVE indicator of engine health and setup, fine, but it shouldn't go any farther than that. The key word here is relative.
Just simple variables in setup of both the engine and the dyno when the numbers are generated can make significant differences in the results. Were the numbers taken when running with the engine's own water pump, alternator and other belt driven accessories or not? Exhaust through headers? Air filter on? etc., etc.
I'm more apt to believe someone who says they have about X hp than the person who gives a specific value.
Changing components for better performance, driveability, fuel efficiency, etc. when compared to a baseline before the changes, sure, but again, it's all relative and I have some relatives that I wouldn't touch with a ten foot pole.
DonC

[Rick Parker]

Horsepower sells engines and parts and is a function of torque. It is the mystic ingredient that we all empty our pockets for. Torque is what you feel when you put your foot down, that's what wins races and accelerates your car.

Rick

[scottj]

I would like a really strong FE for my replica. One that I would expect to, based on flow numbers, make the power Craft claims. This would be the best of both worlds for me: a big FE that runs as good on the track as a decent small block AND social acceptance in the Cobra community.

But, my hopes have been dashed by some of you. Those in the know seem to be insisting that an FE can’t make any power and that it can’t run with a mediocre small block. Oh well, I guess social acceptance will have to wait.

Seriously, I never look at a peak numbers for race engines. I would be more interested in the shape of the torque curve and the average power over a given rpm range than in peak numbers. Drivable torque is more important than peak HP… to me anyway.

An engine builder wouldn’t have to read this board very long though to realize why guys want an FE.

Scott

[wilf leek]

I only put my car onto a chassis dyno to tweak air-fuel mixture, and I was glad that I did, as the original settings were far too close to lean-detonation for comfort.

The dyno operator was extremely open - he said his rig wasn't calibrated worth a damm, could not be compared with any other dyno, and no, he would not "warrant" any output figures. What he did say he would do, and did, was extract around 40bhp more from the engine than it had when it went in. Shows how far out the air/fuel mixture was, plus we recalibrated the advance curve and timing ( I can't believe my engine starts without kickback, with around 20 degrees of static timing advance, but it does, and runs well, with 36 degrees total all in at 3000).
The fact that we had such trouble with wheelspin on the rollers (finally had to do the top end run in 5th - running over 190mph) showed that we had some serious ponies around.
All the dyno operator would say was "well, I run a lot of Ferraris on this dyno, and none of them ever got near the figures we saw today").

This was enough for me. I still do not have any BHP/Torque figures I could bandy about in the bar, but I do have an engine running as efficiently as it can.

From an engineer's viewpoint, (sorry, I am one of those troublesome kind) I can easily see how unscrupulous operators could frig their dyno to flatter to deceive. And I also fully understand why you should not compare figures from one machine to another. These things are not calibrated to "absolute" standards - only comparitive.

The only dyno cells I ever saw that made a reasonable attempt to produce "absolute" figures to rigorous standards belonged to Lotus cars. And they wouldn't take my engine in!

[Turk]

Even if the dynos were calibrated to an absolute reference.

Same maker, same level of resistance, same level of maintenance, adjusted for altitude, temperature and humidity, wouldn't the exhasut system installed give erroneous results to compare one run on one dyno to another elsewhere?

TURK