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Single turbo carb jet size

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Old 09-10-13, 12:25 AM
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Single turbo carb jet size

My current project is installing a single turbo setup on a 85 rx7, which is carbureted. Being that this will be my first blow through carb installation, I am unsure about which jet size to use. I will be using a t40 turbo and pushing 8-10 psi of boost. I will be using a webber 255 fuel pump. Any direction on which size carb jets to buy for this application will be much appreciated.
Old 09-10-13, 12:35 PM
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welcome to the board.

which carburetor? the Nikki or something else?

you're probably better served waiting until tuning time, when you have AFR data. short of that, RotaryShack is good resource for blowthrough 12A information, but i honestly don't know how much Robert is around these days, so you may have to find his number or email. i think he still has a vendor forum/section.

also, there are a few guys in the Gen I section that would be able to share some experiences with you. i think coldy13 has/had one that is/was pretty well sorted.
Old 09-10-13, 12:42 PM
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Originally Posted by diabolical1
RotaryShack is good resource for blowthrough 12A information, but i honestly don't know how much Robert is around these days, so you may have to find his number or email. i think he still has a vendor forum/section.
He's banned.

https://www.rx7club.com/bad-fugly-bu...-ebay-1033344/
Old 09-10-13, 12:56 PM
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again??? wow ...

okay, disregard the stuff about Robert/RotaryShack. i stand corrected, so sorry about that. he may know his stuff, but that will obviously be of no use to you on THIS board.

i'll wait on your responses to my questions, but the rest of what i said still stands.
Old 09-10-13, 01:20 PM
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To be honest I'm really not experienced with carbureted turbo cars at all, so while I do have the stock Nikki I'm not opposed to changing it and am open to suggestions. I did some searching through here to find this out, but didn't have any luck. Ill seek out the one you spoke about on the gen 1 side as well.
Old 09-10-13, 03:19 PM
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no offense, but i sort assumed you had no experience because i'm assuming "Webber 255" was supposed to read Walbro 255 ... and that's too much pump for a carbie. it's also why i asked about the carburetor because i wasn't if it was some sort of Freudian slip.

how long have you had the car itself? i would advise against going Turbo until you have had some time to become familiar with the car and engine in stock form because turbocharging turns it into a completely different species.

that said, if you insist on turbocharging right now, then keep it simple. keep the Nikki. boost prep it and follow the blueprints put out there by those that have done it and shared on the board. as i said, you will NEED to have some sort of running AFR data to know what jets you will need. you will also need to disclose your location because elevation plays a part in the tuning process.

start your homework! search and read as much as you can in the Gen I section.
Old 09-10-13, 04:46 PM
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I have had a first gen for a few years awhile back, but have decided to come back to rotory recently. I have no shame admitted I have no idea about carbs haha. I am taking this as a learning experience. I have yet to being purchasing parts, as you have pointed out I am unaware about many things. I have begun looking at the first gen forums, so thanks for that! Anyways being that I am in Oklahoma I have to deal with high heat and humidity, so I can only imagine tuning will be a hassle. I kinda figured that would be the only way to find out what I need.
Old 09-12-13, 09:16 PM
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I have decided to just do a 13BTT swap, so i will not have to worry about carb issues. It ended up being easier to do than the complete rebuild that was needed for my 12A. Thanks for your help though!
Old 09-13-13, 06:21 PM
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Originally Posted by taylor177
It ended up being easier to do than the complete rebuild that was needed for my 12A. Thanks for your help though!
if you've made up your mind on the REW, that's fine. i will not try to dissuade you. however, with you posting that it'll end up being "easier", i do think you NEED to research it much more.
Old 09-14-13, 11:10 AM
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Sorry I should have elaborated more. I have no experience with tuning carbs, while an engine swap is within my capabilities. I understand ill have to do some modifications, but for me it's cheaper as well
Old 09-14-13, 11:42 AM
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Originally Posted by taylor177
Sorry I should have elaborated more. I have no experience with tuning carbs, while an engine swap is within my capabilities. I understand ill have to do some modifications, but for me it's cheaper as well
What he is getting at is that the 13B-REW swap is a major pain, and unless you have some method of obtaining free parts it will be much more expensive than your original idea. It would be easier to swap to an 87-92 13BT. Most of the swap links in the 1Gen FAQ are dead, but there are still enough left to help you plan your swap.
Old 09-14-13, 12:58 PM
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Yeah that is always an option as well. The main reason I said it was cheaper is that I picked up this rx7 for $300 and it's missing several parts to the engine and others need badly replaced. However the body was straight and the interior was great. As this is just a project car I don't care if it takes work. I'm still in the planning/ research phase however so I'm open to options.
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