2919cc drag motor what size carby's and exhaust

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mikeatshiloh
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Joined: Mon Dec 16, 2013 12:23 am

2919cc drag motor what size carby's and exhaust

Post by mikeatshiloh » Mon Nov 23, 2015 11:11 am

Hi Guys I have been reading here for a while now. I have a few questions that I hope somebody can answer. I have collected all parts needed to build a 2919cc oxyboxer motor for our drag bug, I would like it to rev to 8000rpm so will need to know what size exhaust is required I'm thinking 2 1/8 and also carby's to feed it. I don't think my 51.5 IDA'S with48mm vents will be big enough? I don't know if it can be done, but is it possible to run 2 750 cfm square bore holly's with two throats feeding each cylinder. I can make the manifolds but I just don't know if it would work. Does anyone know if this has been tried before. 58 or 62mm carby's are way to expensive and I already have the holly's. Thanks in advance for any help Mike.

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pocketrocket
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Re: 2919cc drag motor what size carby's and exhaust

Post by pocketrocket » Fri Dec 04, 2015 6:24 pm

If you are going to build that big of a engine. Whats another $3500 for the 58mm or 62mm carbs? What cam are you using? What heads did you get?

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Chip Birks
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Location: Pleasant Grove, Utah

Re: 2919cc drag motor what size carby's and exhaust

Post by Chip Birks » Fri Dec 04, 2015 11:25 pm

I know a guy that has some 58mm throttle bodies that might be available...if you were willing to go the efi route.

mikeatshiloh
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Re: 2919cc drag motor what size carby's and exhaust

Post by mikeatshiloh » Sat Dec 05, 2015 7:54 am

I have been collecting parts for this motor for a few years now. So as I said I already have the 750 holly's, that's the reason for asking about them. I have got an fk 89 cam for it and autocraft 910 heads with 50 inl and 40 exh valves which should be big enough. We are not thinking of trying efi at the moment. Mike

5.0 Chero
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Re: 2919cc drag motor what size carby's and exhaust

Post by 5.0 Chero » Sat Dec 05, 2015 2:57 pm

Sorry but their is no way you need or could ever use 1400 cfm for that small of a motor
a 3000 cc motor running 10000 rpm at 100% VE would only need 530 cfm

mikeatshiloh
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Re: 2919cc drag motor what size carby's and exhaust

Post by mikeatshiloh » Sun Dec 06, 2015 12:12 am

As far as I know a 51.5 ida is capable of flowing 300+ cfm per throat and that is not enough flow for a 2919cc. I think it has some thing to do with individual runners and not enough continuous flow, vacuum thru a single cylinder.

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