opinions on loosing a couple tenths

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opinions on loosing a couple tenths

Postby steelhead » Sun May 03, 2009 11:23 am

I'm asking all who seem informed so I thought I'd post here as well.
Last year the car ran right around 9.00s all year in the 1/8th, but if I manually shifted I would get into the 8's barely. Over the winter I put on some bigger tires and the first 2 times out I couldn't break into the 8's let alone hit 9.00's consistantly.So the 3rd time out I put the smaller tires back on and played with the timing alittle and was running 8.5's to 8.6's. Not being low enough to run in group 3 as it goes 8.00 to 8.99, I tried in group 2 where I had been and second round ran an 8.5 to break out. So my choices are loose a couple more tenths for group 3 or readjust to run in group 2. Group 3 usually has more cars than 2 so I'd like to be alittle lower in the 8's to try.
the cars a 76 Monza 350 0.30 over, first cam up from stock, stock 4bbl manifold with 600 carb, sanderson headers, stock ignition, 350 trans and 2.93 rear. Run 215/60/14 for mid 8's put on 245/60/14 for low 9's.
Any thoughts on what could help to shave a few more tenths so I could compete in group 3.
Lanse
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Re: opinions on loosing a couple tenths

Postby res0o7eb » Sun May 03, 2009 12:07 pm

Lanse,
I am no expert, but it appears that your Monza likes the lower(higher numerically) effective rear gear ratio with the smaller diameter tires.
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Re: opinions on loosing a couple tenths

Postby cjbiagi » Sun May 03, 2009 4:44 pm

Assuming you are hooking up with both tire sizes then I would agree that it is changing your overall gear ratio. What size tires are you using? While the actual gear ratio doesn't change the effective ratio does when you change tire diameter. I'm curious if you know what the quarter mile time would be?
Clyde.........75 Monza 2+2
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Re: opinions on loosing a couple tenths

Postby steelhead » Fri May 08, 2009 2:33 pm

I understand the smaller tires are like a higher gear ratio, and no I'm not sure what my quarter mile times would be. I like the ratio for cruising the highways, so I really didn't want to change it. What I want opinions on is shaving a couple more tenths off to get closer to 8 sec. passes.
Maybe a different intake or a smaller tire yet,some cut outs in the exhaust. I'm not knowledged in what gains can come from a certain upgrades so I was asking for opinions on what I could do to gain alittle.
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Re: opinions on loosing a couple tenths

Postby 73Sedan » Fri May 08, 2009 6:03 pm

Lose from 200 to 225lbs of weight - alum, fiberglass, lexan, removing dead weight....??
You won't be messing with the gearing that way.

Also don't underestimate what a good dyno tune will do to the car! 8)
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Re: opinions on loosing a couple tenths

Postby bill1978v8 » Fri May 08, 2009 6:59 pm

If your running a stock trans and convertor, you could bump up the stall spped a little and go smaller on the diameter of the convertor to help with rotational weight. I also second the good dyno tune if you can.

Bill
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Re: opinions on loosing a couple tenths

Postby 73Sedan » Fri May 08, 2009 9:15 pm

Good point Bill. A great converter is beyond monetary measure. A buddy of mine knows some folks who custom fin a converter based on cam specs/gearing/etc. I've put a message in to him to get the details. I can't believe I overlooked that.

Also there's a custom HEI shop: http://www.performancedistributors.com/index.html. It's the "DUI" distributor. AWSOME bang-for-buck when replacing stock ignition. These WILL give you a butt-dyno noticeable increase in performance.

Lanse, high 8's are VERY respectable for a streeter. When I ran my '76 (8.2x's) I was about the ONLY regular bracket runner who could drive my car to the track, beat the crap out of it (win a few/lose a few) and drive it home. Not being a trailer queen running in the 8's is something to brag about.

Hope we've helped, and I'll get that converter info hopefully by late Sunday.

UPDATE: The torque converter place is http://www.ptcrace.com/index.php
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Re: opinions on loosing a couple tenths

Postby 2lucke4u » Wed May 13, 2009 12:58 am

73Sedan
great point on the dyno tune,I picked up 40+hp and 35lbft,great points are being made,try this also,drop your lca's about 1 1/2 inches,thats where I settled and my car leaves very hard,I'll be hitting the 1.3's this year in the shorts,also air bag the passenger rear at 15lbs of air,use camaro bags if you need to buy them,these two things will not hinder your drivability but pay big in gains,lastly inner supports out of the bumpers and metal reinforcement out of the doors,were talking about 150lbs,,good luck,,keep in touch,,
Charles
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Re: opinions on loosing a couple tenths

Postby Stivan » Wed May 13, 2009 3:12 pm

The convertor will definately help, and maybe not cost you too much on the street. However, weight lose will be the cheapest way to go. To drop 2 tenths in the eighth, means you'd have to take off around 400 lbs, because for every 100 lbs, you'll get a tenth in the 1/4. But a combination of weight lose, and convertor, you shouldn't have any trouble finding that mystical .2's . . .. .

Also, you might check out the "Weight Hunt" article in this forum. Good Luck !!! With your endeavors.

Stivan
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