N/a Dyno 318 H/p 279 Ft/torque

[Geek SHO]

That is so sexy. That car begs to be recorded on video.

 

[Dave Kegel]

There are 10 second n/a 4 bangers pushing 300+whp. This is not impossible.

What are you referring to specifically that is "not impossible"?

Dave Kegel

 

[NJSHO]

Correct me if Im wrong, but
(input torque) x (gear ratio) = output torque?
3rd gear has a ratio of 1.38 to 1.
(input torque) x 1.38 = 279ft*lbs as read on the dyno
That means actual input torque (un-multiplied by the gearing) would be
279/1.38=202.173 ft*lbs
So if you did a 4th gear pull (gear ratio of 1.02 to 1) you should get closer to the 202.173 number. This seems more realistic.

 

[SeanMc]

What are you referring to specifically that is "not impossible"?

Dave Kegel

These dyno numbers. If the built 4cyl motor can put out 300+whp, there is no reason a built 6cyl can't do the same thing. Remember, the only thing "SHO" about this motor is how it looks on the outside. It's pretty much a custom motor.

 

[Dave Kegel]

These dyno numbers. If the built 4cyl motor can put out 300+whp, there is no reason a built 6cyl can't do the same thing. Remember, the only thing "SHO" about this motor is how it looks on the outside. It's pretty much a custom motor.

I think you're missing the point. It's the torque number that is virtually impossible given a 3.0l N/A motor. And given the "suspect" torque number, in my mind it makes the HP number suspect as well since HP is derived from torque.

Dave

 

[drivinhard]

We aren't talking about (or I'm not) hp numbers. HP numbers are basically meaningless. HP is just a math problem of torque (sheer turning force of the crank) and rpm (time).

What I'm referring to are the posted torque numbers. In other words, the force of the crankshaft turning.

IIRC from the article I read about the salt flat SHO motor, it was turning somewhere upwards of 9-10,000 rpm no? That's where the "500 hp" is coming from. Tune it to make it's torque at higher revs. You'll get a high peak hp number. But I can assure you, it's not making 330 ft/lb of torque anywhere in it's RPM range...

A n/a engine can only make so much torque for it's displacement, at any rpm, period. It only has the resonance tuning of it's intake to acheive good cylinder fill and a high VE number. Since there is no aid of extra oxygen/fuel through adding more via a turbo, supercharger or N20, an n/a engine is forced to make high hp numbers by making "hp" by using high rpm. It's that simple. It may not have a hp "limit, or an RPM limit, but it WILL have a torque limit.

I'd say if you are doing about (peak) 1.45 ft/lb of torque per cube (n/a motor only) you are doing VERY good. Anything beyond that is very, very difficult. This is going to hold true for 99.9% of any n/a internal combustion engine in the world. And to get to that number and beyond, you'd need favorable (torque biased) rod ratio, out of this world VE, VERY high cylinder pressure (very high dynamic compression ratio) and some mightly explosive jungle juice...

 

[Bluto2000GS]

That is awesome
Congrats!

 

[SeanMc]

I believe he said his CR is up around 11:1. Add some race fuel, and I'll say it again, these numbers (hp and torque) are not impossible.

 

[Dave Kegel]

I believe he said his CR is up around 11:1. Add some race fuel, and I'll say it again, these numbers (hp and torque) are not impossible.

What are you basing this statement on? The entire history of the internal combustion engine and all sorts of mathematical equations say differently.

Dave

 

[SeanMc]

I'm not an expert on the subject, but I believe these numbers.

 

[Dave Kegel]

I guess I'd like to get a "second opinion" as they say. I'd like to see the results of a Dynojet.

Dave

 

[drivinhard]

Basically we are talking about 1.85 ft/lbs per cube. Sorry, that ain't happening.

Here's a fairly short but good article

http://wahiduddin.net/calc/cf.htm

I'll copy the last section here:

"This is a great formula. Basically it says that if you can keep the same amount of torque, then the more rpm you can turn, the more horsepower you get!

That's why Formula One and CART and IRL engines all turn incredible rpm. The faster the engine turns, the more power it can make (when it's properly tuned to operate at that speed).

Consider for example: a normally aspirated internal combustion engine typically produces about 1 to 1.5 ft-lbs of torque per cubic inch when it is properly tuned to operate at any specific rpm. With a 2 litre (1 litre is about 61 cubic inches) engine, producing 1.5 ft-lbs of torque per cubic inch, you would expect to get about 180 hp at 5200 rpm... but you will get a whopping 415 hp if you can get it to run at 12,000 rpm.

The 3.5 liter IRL engine is reported to produce about 650 hp at 10,700 rpm. That would be about 1.5 ft-lbs per cubic inch.

The Ferrari 3.0 liter Formula One engine is rumored to produce about 860 hp at 18,500 rpm. That would be about 1.33 ft-lbs per cubic inch.

And at the other end of the rpm spectrum, one model of the 360 cubic inch four cylinder Lycoming IO-360 aircraft engine produces 180 hp at 2700 rpm, which is 0.97 ft-lbs per cubic inch.

In general, production automobile engines that have a broad torque band will produce about 0.9 to 1.1 ft-lbs per cubic inch. Highly tuned production engines, such as the Honda S2000 or the Ferrari F50 are in the range of 1.1 to 1.3 ft-lbs per cubic inch. Highly tuned race engines such as NASCAR, IRL and Formula One are often in the range of 1.3 to 1.5 ft-lbs per cubic inch."

 

[Dave Kegel]

Here's a formula to determine the required VE of a motor, given the HP and RPM requirements:

REQUIRED VE = ( 9411 x HP x BSFC ) / (DISPLACEMENT x RPM)

BRAKE SPECIFIC FUEL CONSUMPTION (BSFC) is generally .44 - .45. Using .45 for BSFC and plugging in the WHP numbers of 318 @ 6300 RPM gives you a required VE of 117%. And remember, this is with the wheel numbers. I'm pretty sure the formula is based on crank numbers which would push the VE requirement much higher.

As you can see, it's not going to happen. You can't get a 117% VE without a blower.

As I said earlier, I'd run it on a Dynojet and see what numbers you get.

Dave

 

[drivinhard]

And that's at the peak hp number. Since peak VE generally equates to the peak torque number, lets plug in the peak torque figures (hp at the peak torque/rpm intersect) and use the crank numbers (I'll say 325 ft/lbs, it's ballpark). So eyeing the chart, ~320 hp (crank) at ~5100 rpm

You come up with about 145%.

 

[HoustinoJillian]

not that i don't trust you all/believe you know more about this than me, but what effect does 112 race gas have vs running premium (92-94). just a general guess/percentage for a NA motor stock or modded.

i'm not claiming that these #s could be due to the race gas, merely trying to see how much that would contribute to a power increase.

 

[drivinhard]

The SHO has a good enough combustion chamber you could probably run 94 pump @ 11:1 compression ratio (which i believe is what he posted his had earlier). It might would be close. Regardless, it's not a high enough CR that it's going to take fulll benefit of running 112 octane fuel. I'd guess any power increase (I've heard up to 3-4% from pure blend race gas) is mostly due to it not having a lot of the added EPA blended junk (alchohol, etc) you get with pump gas.

I think Todd Cook and Dan B.'s n/a 3.2L SHO engines both run close to 12:1 comp. I know at least Todd's does. Dan's has +40 cams and has one of the best n/a dyno curves as far as peak torque, torque curve, and hp I've seen. Dan runs Cobra brakes so this was measured wheel hp on a dynojet with the 17" road race tires (17x8) and big Cobra brakes (neither of which help whp numbers).

 

[Shoaz]

I'm not an expert on the subject, but I believe these numbers.

I think that sums up the general problem right there.

 

[Brett]

They dont believe your numbers, honestly i dont have an opinion, but from the sounds of it everyones raising So what to do? get video/array of pictures. if you dont well, most will think/know its bs, if you do, you'll make alot of people feel like dummies.

 

[40BelowSummer]

They dont believe your numbers, honestly i dont have an opinion, but from the sounds of it everyones raising So what to do? get video/array of pictures. if you dont well, most will think/know its bs, if you do, you'll make alot of people feel like dummies.

What will video/pictures prove? Definitely not torque. If he wanted to he could run it on another dyno; like maybe a dynojet. But he doesnt have to prove shit, just kick ass on the salt flats.

 

[SuperHO]

....why doesn't he just do a dyno run in 4th gear on a dynojet? I mean, aren't dyno pulls with MTX cars usually done in 4th?