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1985 RX7 more power? (intake?.maybe?)

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Old Dec 11, 2012 | 10:41 AM
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From: Danbury Texas
TX 1985 RX7 more power? (intake?.maybe?)

I have a 12A with a Holly carb. We are running in the Chump Car and Lemons races.
I am looking for some advise, what is the best way to get the most power out of the 12A motor?

Would a hood scoop help, maybe try to force a little more air thru the carb?
Any suggestions or help would be appreciated.

Thanks

Last edited by misterstyx69; Dec 11, 2012 at 03:06 PM.
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Old Dec 12, 2012 | 11:27 PM
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Headers and catback exhaust.

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Old Dec 13, 2012 | 06:09 AM
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Thanks for the reply!
The car has headers and the Cat has been removed. was done by the previous owner.
I need to put a new muffler on the car, our is blown out!
I was looking on the web and found a Holly Intake for the 12A, ours has the stock intake.
What your opinion on the aftermarket intakes?
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Old Dec 13, 2012 | 11:32 AM
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By 'intake' are you referring to the intake manifold below carb or the ducting that directs air into the carb?

I thought all Holley's use a custom intake manifold since it doesn't bolt in place of the stock carb. Might want to double check that. Not much to gain there.

If it's the the air ducting to the carb. Remember it's lemons. Cut a hole somewhere and connect some dryer ducting from the air cleaner to the hole. Extra points if you make it hand operated and call it a DRS system.

Overall, you'll probably get more out of a wideband and re-jetting the carb. Stuff the inspectors won't ding you points for. You will get murdered in the straights running a 12a in lemons. Not really any way around it. Just have to out-corner them and have fun out there.
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Old Dec 13, 2012 | 12:12 PM
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Thanks for the info.
yes, I was talking about the Intake Manifold. Not sure if it is stock. don't realy know what I am looking at yet!!. It doesn't look like the one I saw on the web. Looked more like the stoke ones I saw pics of. I am still learning! We do have another Carb that is supposed to be hopped up., Holly.
I will open it up and see what jets it has. What jets would you recommend?
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Old Dec 13, 2012 | 12:32 PM
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Carb jetting and venturi sizing is voodoo black magic that I do not comprehend. Here's some info about aftermarket carbs on fb's. Good luck.

Mazspeed's First Generation Rx-7 Club Page

We ran an old pro7 car in lemons on the stock carb. Seemed to do fine, but a stock 12a can't match a ford 5.0 that "fell off a truck". Pass people in corners and have fun. When you start scratching the itch for more power, that's when stuff breaks. During a race, driving a slow car is more fun than fixing a fast one.

Aftermarket carb's do have more power potential, but need to be tuned correctly. Don't assume the previous owner knew what they were doing. If you don't have anyone that can tune the carb for the rotary, I'd suggest finding a stock carb and manifold.
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Old Dec 13, 2012 | 03:05 PM
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The best way to get more power would be to do a rebuild and have the engine streetported, Bridgeported, or peripheral ported.

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Old Dec 13, 2012 | 03:29 PM
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Originally Posted by wthdidusay82
The best way to get more power would be to do a rebuild and have the engine streetported, Bridgeported, or peripheral ported.

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While that is corrrect, it is hardly economical for a chumpcar/lemons racer where your total budget is supposed to be $500. The judges are car guys and can definitely spot a brapping peripheral ported engine from a normal 12a you can get for a couple hundred bucks.
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Old Dec 13, 2012 | 05:06 PM
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Yea you're definitely right, I don't know the rules.

The only other things i can think of are you could do are an aftermarket ignition and remove accessories to lose weight on the car.

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Old Dec 14, 2012 | 11:46 AM
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Thanks for the help!
I think I will start with re-jetting the Carb
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Old Dec 14, 2012 | 11:58 AM
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Originally Posted by RXSpeed16
While that is corrrect, it is hardly economical for a chumpcar/lemons racer where your total budget is supposed to be $500. The judges are car guys and can definitely spot a brapping peripheral ported engine from a normal 12a you can get for a couple hundred bucks.
All just depends. Worst case would be bribe penalties.
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