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Weight Reduction to improve power to weight ratio!?

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Weight Reduction to improve power to weight ratio!?

Postby gryffinwings » Fri Nov 11, 2016 6:26 pm

So I've been thinking to myself about how to reduce weight of my 1st gen CRX Si to be lighter weight, however my aspirations to do that might be a bit difficult do to the fact that the 86-87 Si is the heaviest variant of my generation at a weight of 1,978 lbs. I was thinking to myself about trying to improve the power to weight ratio to something like the C5 Corvette, however that is a very lofty goal. Getting some math down:

1987 Honda CRX Si:
Engine: D15A3
HP: 91
Weight: 1978 lbs
Power-to-weight ratio: 0.046006066734075

2004 Chevrolet Corvette
3,214 lbs
HP: 350
Engine: LS1
Power-to-weight ratio: 0.10889856876167

Now, there is no way any amount of weight reduction is going to produce that kind of power to weight ratio that the vette has with the stock D15A3 engine, even if you could drop the weight to 1000 pounds, you are at 0.091, so... not quite there yet, so a balance of weight reduction and increase in power output is needed.

Now, say if a stock B16A engine is installed, that's around 160 HP. Weight would need to be reduced by approximately to 1500 lbs.

1987 Honda CRX Si
HP: 160
Engine: B16A
Power-to-weight ratio: 0.10666666666667

Now that's basically in my mind, close enough, however, I'm wondering if you can even reduce weight that much. However there is another engine that could be installed, not sure if there are any off the shelf mounts for it, and that is the F20B, makes 200 HP, you could use an H2B conversion kit to possibly make it work.


What do you guys think? Is 1500 lbs doable? Or is there a more feasible solution?
1987 Honda CRX Si
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Re: Weight Reduction to improve power to weight ratio!?

Postby Myriad » Sat Nov 12, 2016 1:24 am

To get the same power to weight ratio as the Corvette in the 1900 lbs crx, you'd need 208 HP.

Which is easier: 1.) Cut 400 lbs off of the body and slap a stock engine in it, or
2.) hook up a turbo to a stock engine?

Even if you want to stay NA, it's still ridiculously easier to build a motor to 200 HP than taking more than a couple hundred pounds off the body.

I don't like to shut down thoughts, so I'll contribute. A carbon Fiber hood, fiberglass fenders, lexan windows instead of glass, and removing the plastic interior and carpet will make gains. Mind you, there might need to be some fabrication.
I got a new shell, just need to stop driving the DX so I can work on it.

I've got a filter for my mouth, it just isn't a good one.
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Re: Weight Reduction to improve power to weight ratio!?

Postby Mista Bone » Sat Nov 12, 2016 3:26 am

89 CRX HF under 1800 lbs before rear disk conversion.

OP has crappy info....and this mindset is worthless.
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Re: Weight Reduction to improve power to weight ratio!?

Postby jlicrx » Sat Nov 12, 2016 11:26 am

Mista Bone wrote:this mindset is worthless.

consider the torque:
LS1 - 365 lbf
B16A - 112 lbf
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