231 or 252 tr7?

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6PAK72
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231 or 252 tr7?

Post by 6PAK72 » Sun Dec 18, 2011 8:14 pm

Conundrum.

The 231 Buick is 35 pounds lighter than the 252, but the 252 can be built 55 hp higher at about the same cost with somewhat less aggrevation. Suspension parts to update the front end are easily available for the tr7. Drivetrain mods are identical.

Would you build for weight or horsepower?

As a note, the 252 with an Edelbrock carb, cam, intake and header kit runs about 250hp. Not bad from a push rod
6 in a 2100 lb car.
Jeff Baker
Wilton, NH
#42 95 Miata
72 TR6
79 TR7 V6 in shed

dinoracer
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Re: 231 or 252 tr7?

Post by dinoracer » Sun Dec 18, 2011 9:53 pm

More Horsepower!

When you're done putting in the bigger motor, the next project can be a carbon fiber hood. Problem solved.
Tom Cannon

Former COM Chief Steward (fka Chief of Operations, Chief of Tech, assistant BBQ cook, Club Secretary....I been around a while)
#26 - 2000 Black Miata (sold) - co-driver of the orange 318ti .. thanks Scott!

Chrispy
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Re: 231 or 252 tr7?

Post by Chrispy » Mon Dec 19, 2011 9:11 am

In terms of raw performance when the HP beats the weight it is typically a no brainer. However I would go after whichever engine build is going to be the strongest and most reliable.
Chris Parsons
#22 - 95 Miata

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Re: 231 or 252 tr7?

Post by TroyV » Mon Dec 19, 2011 10:26 am

What is this car for?
Troy Velazquez
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jlwhorf
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Re: 231 or 252 tr7?

Post by jlwhorf » Mon Dec 19, 2011 10:36 am

You just want to make sure you build an even fire engine.

paultg
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Re: 231 or 252 tr7?

Post by paultg » Mon Dec 19, 2011 1:12 pm

"No replacement for displacement" :-)

Beyond the HP numbers I'd look closely at the torque curve and RPM range, and see which motor makes the most sense for the cars purpose (see Troy's comment).
Paul G.
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CP
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Re: 231 or 252 tr7?

Post by CP » Mon Dec 19, 2011 9:37 pm

What does the current powerplant weigh in at? And does the nose plow with the current engine (autox and track)?
-Cy
99 Spec Miata (SM/STU/STL/EP)
2011, 2013, 2014 NER STU Champion

6PAK72
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Re: 231 or 252 tr7?

Post by 6PAK72 » Thu Dec 22, 2011 7:41 pm

Since the engine is about toast, and every piece of rubber is shot, we are aiming to build it into a nice handling, go kill some cones once in a while car.

The current slant-4 Rover engine (also used in the Saab) is a cast iron block, weighs about 548 pounds. The Buick 231 even-fire aluminum block weighs 437, the Buick 252 (same block) is 472 pounds.

Edelbrock offers a kit for both: carb, intake, cam, headers. Costs the same for either engine. It's a 550cfm on the 231, a 600cfm on the 252.

The current engine plows like a yoke of Oxen. That could have something to do with the factory front spring rate being 95 pounds. Yes, that's 95 pounds.

The Koni coilover replacement kit starts at 260 pounds and goes up to 380 on special order.
Jeff Baker
Wilton, NH
#42 95 Miata
72 TR6
79 TR7 V6 in shed

Tim Mahoney
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Re: 231 or 252 tr7?

Post by Tim Mahoney » Fri Dec 23, 2011 10:51 am

Jeff,

Call Woody at The Wedge Shop, he's done the Rovers & Buicks in TR7/8's for years. He knows the primary failure points (cooling) and has the fixes. Also stocks headers, urethane suspension bushings and all things Wedgy.

http://www.thewedgeshop.com/
#6-SPB

6PAK72
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Re: 231 or 252 tr7?

Post by 6PAK72 » Sun Dec 25, 2011 3:21 pm

Thanks, Tim.
Jeff Baker
Wilton, NH
#42 95 Miata
72 TR6
79 TR7 V6 in shed

6PAK72
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Re: 231 or 252 tr7?

Post by 6PAK72 » Mon Dec 26, 2011 12:02 pm

I wonder if the upgrade kit includes this exterior trim option?
White accents on Silver-  kind of subtle don't you think?
White accents on Silver- kind of subtle don't you think?
TR7.JPG (18.42 KiB) Viewed 2327 times
Jeff Baker
Wilton, NH
#42 95 Miata
72 TR6
79 TR7 V6 in shed

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