Ok so this boils down to one of those will car A be faster than car B type questions, but it puts things in perspective. First things first, these dyno's are only dramatizations and should not be taken as absolute, however I feel they are fairly accurate. And yes I created the picture myself.

The first one is what a Stroked and Bored out (95mm x 84mm) B18B (Non VTEC, basic mid RPM bolt-ons) might look like against a standard B18C5. You can see that the C5 has higher horsepower, about 25 more. However what is important is to look at the area below this. Under 6000 RPM's the ITR is getting killed. So the Question is given the spread out nature of the LS transmission, you think the B18B got a chance against the venerable C5? Also note that a engine like the B18B would be extremely fun and easy to drive around town.

For the B18B I made the TQ build up down low due the decreased Rod Ratio of the stroked motor. This coupled with the Non VTEC head would then cause the power to fall off around 5000 RPM's. All though you may think we hell, we can extend probably another 1500 RPM's with a VTEC head, this also offers as protection against over revving the motor, again a side effect to rod ratio. This is also why I would use things that help to build low end power, such as a 4-2-1 Header and long AEM?Injen style intake, and keep the stock LS intake manifold...maybe some extrudehoning would be in the works.




This next image is what I think the same engine with a small T25 or T3 turbo kit would be like. It's kinda like a VW GTI Vs a Honda, even though the Honda's got some mad VTEC skills, its just so hard to fight the TQ.




Anyways, let me know if I should change anything on the dynos that would make it interesting, or if you think something is wrong.

Just trying to spark some fascination here.



[Modified by Westrock2000, 1:06 AM 2/8/2003]

 

Multiply your two hpothetical torque curves by the respective transmissions' overall gearing to get a better picture of your hypothetical vehicle performance.

 

I don't mean to be a bitch, but the 2.2L is actually a 2.1L

Anyways, I think the 2.1L would have more power than that. Its only at 140 hp.

 

See I always wondered how that math works

A stroked B16 -> ~1.8L
A stroked B18 -> ~2.0L
A bored B16 -> ~1.8L
A bored B18 -> ~2.0L

So how come a stroked and bored B18 only = 2.1L?

 

Yes thats my next task, to see what the HP curves would look like when applied to the Transmission gearing. Maybe to see the difference of a LS transmission with a 4.929 FD would have in respects to a SI or ITR tranny. Although I do have some pics of just a speed/rpm graphs....see if I can find them....

 

Because (84 x 84 x 95 x 4 x .7854)/1000 = 2105.9 cc (2.1L)

bore x bore x stroke x # of cylinders x .7854 (a constant) = displacement

 

Plot the torque x gearing, the horsepower is useless for finding the force of acceleration.

 

Good call on the displacement!

Now for the gearing, would it be something like TQ x [gear] x [final]? ex: 132 x 3.23 x 4.40

Or how would that work exactly? Am I basically just trying to spread the torque out so as to show how much torque at a certain speed I am making? Cause I think I understand that much better.

 

Yep, that's exactly how it works. It's called effective torque to the wheels, you can just plot it over mph and the gearing. This is actually how you figure optimal shift points; wherever one gear's effective torque curve intersects the next higher gear is where you should shift. Note: on these small displacement high revving motors, often the lower gear plots never crossover. The torque multiplication factors and high RPM power output mean shifting at redline is the best shift point in terms of maximizing acceleration.

Ps- If you need any other auto math just ask

 

you need to keep in mind thou the R-spec revs to 9k vs ~7k or so in your graph, so it can be geared 22% (i thikn its 9000-7000 / 9000rpm) shorter and still max at the same speeds in each gear (vs the bored out lower reving motor), that is a near direct increase in effective torque/power at the wheels.

Also, the torque of the stroked/bored out motor drops sharply after 5252 rpm to the redline, not good for straight line racing. Torque dictates acceleration. The larger displacement example only has an advantage in 1st gear where the R-spec motor has to get the revs up.

 

Texan,

Your smart!

http://www.hondalife.com/articles/gearratios.htm

 

How the **** did you find that old thing?!?

 

Ya haha!

I saw that and was like "huh...I'll be damned....what are the chances"

That is funny though. to a helping hand!

 

All right heres one with a VTEC head...I would probably go with a full GSR head, including the dual runner setup, to help out the low end. As you can see with the torque leveled off (more so at least) the horsepower really takes off. The VTEC head may even make the Torque stay flat until 7K. Even if you only had 145 Ft-Lbs at 7K RPM that would still be 193 HP.



Man this is fun!

 

Great graphs
I also do the same ****, but I modify my graphs on cad.
People need to understand that torque & gearing is more important than peak power figures. Torque is hard to produce since is directly dependant on displacement, and the characteristics of the curve depends on bore/stroke & rod/stroke. If the setup produces a lot of torque, it has the potential to produce more power.

 

Obviously, since power = torque * rpm

 

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