SL-C recommended engine/transaxle combos

[Ken Hahn]

As for the HP/liter argument, when I had a 3L twin-turbo motor, that was all I cared about and I was making about 130hp/liter. Somehow when I bought a Viper, I realized just how lame that metric was as it was just a way to avoid the topic of what my total HP output was.

Is it cool to make 400HP out of 3L at high RPM? - you bet. Is it better than making 700hp out of 8L at lower RPM? - ummm NO. Not to me anyway.

Naturally aspirated, the LS platform kicks the Viper's but too. I see in my passionate hasted I wasn't clear when I said "the bigger engine wins" in a race even with less "hp per liter".

How exactly did you come to this conclusion? Last time I paid attention to T1 for instance, the Viper had to run a 280lb weight penalty and 40% restrictor plate on the intake over the Z06 and that was with the older Gen 3 motor.

 

[Ricardo Montalvo]

Let's not be quite so absolutist. No measuring stick is bogus in absolute terms; each one's value is determined by the individual's perspective and goals. From an engineering challenge or expertise point of view power/displacement is an interesting measure.

As end-users we tend to be interested more directly in power/cost, power/mass, maintainence cost/operating time, along with a series of intangibles/unmeasurables such as sound quality, design esthetic, maintainability. Until we all agree on a weighted set of measurements we're never going to agree on a single metric.

1st paragraph: Fair point. Absolutes are a horrible way to defend a point and are easy to target and prove wrong. Guilty as charged. However, I still think it's a bogus measurement to determine an specific engine platform superior to another engine platform.

2nd paragraph: Agree 100%. Therefore if a user likes one engine over another due to a mix of subjective and objective measurements, more power to him. Different strokes. No argument here.

So, what we've concluded so far is:

- If it's not an LS engine it's wrong

- If it's not at least 500cid it's wrong

Okay, carry on then

Not quite, that's more subjective. Although I tend to have extremely similar opinions although my engine isn't 500ci unfortunately.

In the end, all that matters are lap times given the same platform. How many cubes, hp/liter, hp/$, east/west/european, pushrod/ohc/rotary or any other lame never ending points of debate are irrelevant. There is more than one way (i.e. engine choice) to get the fastest lap and he with the most power (bragging rights only) is not guaranteed any FTD's.

Well said. Totally agree. 4 rotor wins for cool factor too. :thumbsup:

 

[Ricardo Montalvo]

As for the HP/liter argument, when I had a 3L twin-turbo motor, that was all I cared about and I was making about 130hp/liter. Somehow when I bought a Viper, I realized just how lame that metric was as it was just a way to avoid the topic of what my total HP output was.

Is it cool to make 400HP out of 3L at high RPM? - you bet. Is it better than making 700hp out of 8L at lower RPM? - ummm NO. Not to me anyway.

I went through the same exercise when I raced a single turbo Supra. Then people started supercharging LS engines and Viper motors. They were all making the same or more HP to the wheels on 93 octane pump gas that I needed 115 octane leaded gas and 35psi to make.

I realized then at double the displacement I could make an enormous amount more power with the same octane and less rpm.

How exactly did you come to this conclusion? Last time I paid attention to T1 for instance, the Viper had to run a 280lb weight penalty and 40% restrictor plate on the intake over the Z06 and that was with the older Gen 3 motor.

In my overzealous haste to shoot down the HP per liter argument while at the same time defending the push rod engine, I blurred the 2 points. I brought up the WC series example for the HP per liter argument as much as the push rod defense.

Your point supports the HP per liter one. I won't argue your point about the Viper being more restricted than the LS engine in racing series. Stock for stock the Viper motor makes more horsepower than the stock LS. It should as it is a fairly efficient design and much larger. The governing bodies of these series change rules so often to "level" the playing field I stopped caring to keep up with them.

However once the aftermarket comes to play, I have yet seen a stock or built naturally aspirated Viper engine make more power than a built naturally aspirated push rod LS motor on 93 octane.

Doesn't mean it doesn't exist, but I have never seen it, and I did look (admittedly not super hard once I decided I wanted to go forward with the LS over the Viper platform).

Ie: Even if the Viper motor fit, I would still have stuck with my current LS based engine.

 

[Ricardo Montalvo]

Basic reasons an argument over HP per Liter is bogus:

Even using the BMW motor as an example. If you make it larger, it will:

a) make more torque (at a lower rpm)
b) most likely make more hp (at a lower rpm)

It's going to choke out the heads/intake system at a lower rpm while increasing torque and providing a much broader torque curve. ie: higher average torque and HP.

Guess which motor will accelerate a car faster? The bigger one.

But which motor will have a higher HP per Liter #? Most likely the smaller one.

The only way it won't is if the smaller motor was valve train/shortblock limited to spin high enough to max out/choke the heads and manifold, but the larger motor was able to max out/choke the heads at a lower rpm where the vavletrain/engine was happier.

Otherwise, the smaller motor would make more HP per liter (or cube), but the bigger engine makes more power, and accelerates the car faster.

No one ever got caught cheating using a smaller engine in a restricted Race series.

If you like the small peaky engines because you like to rev high, create more friction in your engine which break and wear out parts faster then more power to you. Enjoy.

I'll take my beastly low tech, low HP/liter motors and we can all be happy.

 

[Mesa]

If we are talking a Laguna Seca - light makes right, if we are talking Lemans and the Mulsanne then the bigest HP number wins. In the end the lightest engine with the lowest cg making the most HP wins if it's based on lap times only. But if we are talking anything else it quickly becomes subjective, then it's personal preference and there is no winner in that battle.

 

[Rick S.]

I think I prefer a larger more moderately tuned motor than a smaller and higher tuned one...but that's just me.

 

[Alex]

Not quite, that's more subjective. Although I tend to have extremely similar opinions although my engine isn't 500ci unfortunately.

Step 1 - Remove cheque book from pocket

Step 2 - Write larger cheque

Step 3 - Cake! Mmmm, cake. :drunk:

See, that was easy to fix

 

[Ron Earp]

The area available under the horsepower curve is where it's at, not the peak horsepower number. Somewhat subjective, but I'm not a huge fan of engines that produce their horsepower over a narrow RPM band, i.e., peaky. Low and mid range horsepower (torque produced a lower RPMs) allows you to mask those pesky mistakes on the race track.

On a slightly different note I feel the LS engine has had some detrimental affects to those enthusiasts that enjoy some diversity in their car hobby. The LS platform is a good one, but it has now become the "easy button" for anyone building a car. LS engines must install themselves as many of them as I see in various cars.

I popped in a small car show a couple of weeks ago and damn near anything custom had an LS engine in it. Vintage Dodge truck - LS7. Old Ford wrecker - LS motor. 50s Chevy Rod - LS motor. Ford three windows - LS motors. Buick Grand National clone - LS motor. RX7 - LS motor. It is sort of like the 350 Chevy was on the rod scene back in the day but far worse. When my sink disposal goes I think I'll replace that with an LS motor.

 

[Paul Osborn]

I think I prefer a larger more moderately tuned motor than a smaller and higher tuned one...but that's just me.

Yes; driving a grenade around gets old if you're the one who pays the bills.

I haven't seen reliability mentioned as a factor, and for a street car I think it counts.

As for efficiency, one measure that I consider is HP per $. An LS3 = $6500/430hp = $15.12 per hp. A BMW M5 motor =$9000 (long block)/400hp = $22 per hp.

After market parts availability (heads, cam, etc.) and cost are factors too.

Sure, a superior driver with an unlimited budget will not be satisfied.

 

[Dave]

When my sink disposal goes I think I'll replace that with an LS motor.

Now there is an original idea.

 

[Les]

I think I prefer a larger more moderately tuned motor than a smaller and higher tuned one...but that's just me.

Yes; driving a grenade around gets old if you're the one who pays the bills.

I haven't seen reliability mentioned as a factor, and for a street car I think it counts.

Thank you, rstallbaum and darteaus.

I addressed that in one of my posts in the "Re: My RCR "DPE-962X" 8500 RPM -1500HP Engine Build *lots of pics*" thread:

I have some questions about RCR "DPE-962X" 8500 RPM -1500HP engine. Now, hang on! I might sound like a curmdgeon upon first reading, but rest assured: I am not. These are questions I do not have the answers to.

I have been re-reading the November 2003 issue of "Hot Rod" magazine, in which they describe both the technical specifications and the development of the engine Ford put into their 2004 Ford GT supercar. Here is a link to that article: Ford GT - Aluminum Supercharged 5.4L V-8 - Overview - Hot Rod Magazine

Ford met their performance targets for the Ford GT engine of at least 500 horsepower and 500 pounds-feet of torque.

Ford GT Engine and Transmission Cutaway

While Ford was reaching those performance goals, they also developed the engine to be as reliable as any of their other motors. That way, they could warranty the engine, just like any other (so says the article).

To meet Ford's own standards of reliability, they tested the Ford GT engine rigorously. According to the article, to make sure that the exhaust headers would not crack, Ford put the engine on a dynamometer and ran it, under full load, and at wide open throttle (WOT), for 150 hours straight.

Ford GT Engine on Dynamometer

To prove that the entire engine was reliable, Ford mounted the engine on a dynamometer and ran it between the engine's point where it produces peak torque and the point where it produces peak horsepower, for 300 hours, straight. The 300-hour test is supposed to simulate 150,000 miles of road use. The Ford GT engines passed those tests.

Could your engine pass those tests?

Would you even want your engine to pass Ford's engine reliability tests?

What standards of engine reliability are you aiming for? What levels of reliability would you accept? Are those two standards different in any way?

Again, I do not know the answers to these questions. I read the article, thought of you, and I ask.

Thanks,

Bassanio et Portia.

So, I guess to ask the same questions here would be appropriate for each poster:

• Could your engine pass those tests?

• Would you even want your engine to pass Ford's engine reliability tests?

• What standards of engine reliability are you aiming for?

• What levels of reliability would you accept?

• Are those two standards different in any way?

Bassanio et Portia

 

[Paul Osborn]

OK. This thread has officially had a stake driven through its heart.

DEAD.

 

[Roger]

Now there is an original idea.

Pretty close:

Jeremy tries another of his V8 powered inventions (series 12, episode 3) - BBC Top Gear