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Car is 1972 Manta 4 spd. Basically stock. I actually bought it about 15+ years ago. I drove it for a bit, then it came of the road. The other projects got my attention and the little Opel sat. Now the Opel is back in the driveway and it's time to start doing something with it. I'm going for a mostly stock refresh.
I don't need to go fast, just need to go at an acceptable acceleration, if my memories of driving it are correct, it was a blast to drive, but acceleration was pitiful. Given the weight of the car and reading posts it does not seem to take much horsepower to get going.

I'd like the get it in the 7.5-8.5 second 0-60, 15.5-16.5 1/4 mile range or thereabouts. What horsepower do you think I'd need to get there?

Thanks!
Nick
 

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Car is 1972 Manta 4 spd. Basically stock. I actually bought it about 15+ years ago. I drove it for a bit, then it came of the road. The other projects got my attention and the little Opel sat. Now the Opel is back in the driveway and it's time to start doing something with it. I'm going for a mostly stock refresh.
I don't need to go fast, just need to go at an acceptable acceleration, if my memories of driving it are correct, it was a blast to drive, but acceleration was pitiful. Given the weight of the car and reading posts it does not seem to take much horsepower to get going.

I'd like the get it in the 7.5-8.5 second 0-60, 15.5-16.5 1/4 mile range or thereabouts. What horsepower do you think I'd need to get there?

Thanks!
Nick
From my own experience, 140 ‘honest’ Hp netted these results.

0-60 in 6.71seconds
0-100 in 17.86 seconds
1/4 mile in 15.0 @ 93 mph
Top speed 137 mph

With stock 3.44 rear axle, but with close ratio ZF 5-speed. 1:1 5th gear. Ultimately, traction was the limiting factor.
 

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Just Some Dude in Jersey
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14,389 Posts
I don't normally get into this engine hp stuff and so my quoted numbers may be way off and generate dispute. I'm just going to state the general overview of our engine's hp ratings, just to keep the conversation moving for you.

The early '68-'70 1.9 liter engines were high compression and generated about 90hp. That's a good hp for our light cars. From '70 onwards they had to dumb down our engines for emissions to a low compression variety that generated 60-75 hp. So, you probably have a low compression engine. Around 1975, Opel came out with big valve 2.0 engines, I presume they were high compression, and those had hp around 100-110, plus they breathed much better. Most people who have upgraded their engines have gone the big valve 2.0 route. A stock engine can be machined to that spec without too much trouble. It's a very satisfying amount of hp for our cars. Add a cam upgrade and things get even better in regards to hp and high speed. Much later Opel came out with 2.2 and 2.4 engines. These are hard to get and more expense are required to set them up. You might get lucky and find someone who has a used 2.0 to sell you and you could try that out for not too much money.
 

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Opel Rallier since 1977
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From my own experience, 140 ‘honest’ Hp netted these results.

0-60 in 6.71seconds
0-100 in 17.86 seconds
1/4 mile in 15.0 @ 93 mph
Top speed 137 mph

With stock 3.44 rear axle, but with close ratio ZF 5-speed. 1:1 5th gear. Ultimately, traction was the limiting factor.
Pretty close to what this popular drag racer's calculator shows...put in the power and weight that you chose... ET-MPH-HP Calculator
 

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Can Opeler
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You will get what you are looking for with about 90-100HP at the wheels. AKA a bone stock 2.0L with stock cam and a single DCOE.
My car does 0-60mph in about 8.5mph with slicks and that set up. When I had 78 rear wheel HP with a 38 DGAS 0-60 was about 9ish and trap speed was 78mph I think I was high 17s at the strip.

I would imagine I’d be high 16s now. My Opel is tuned for high rpms instead of torque now.
 

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As Knorm65 said. An honest 90 - 100 rear wheel hp is an excellent goal and really boosts the fun factor in these cars.
 

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Detritus Maximus
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Bob, are you numbers for a Manta or GT? And was it lightened much?
Isn't the Manta a couple hundred pounds heavier than a GT and a bit less efficient with respect to the drag coefficient?
 

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Bob, are you numbers for a Manta or GT? And was it lightened much?
Isn't the Manta a couple hundred pounds heavier than a GT and a bit less efficient with respect to the drag coefficient?
1973 Ascona. The car weighed 2170 lbs without me in it. As aerodynamic as an outhouse. Acceleration really fell off after 125 mph.
 
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