Building for boost

MightyBoy tech questions and answers.
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XiT
Posts: 117
Joined: Wed Sep 12, 2012 6:48 pm
Location: Hervey Bay

OK so the little frog rocket is getting a complete engine rebuild in the new year with a mild cam grind to go with. Is there any special work I should ge t done during the rebuild to supercharge it not to far down the track ? (Dizzy regraph will come at time of charging) Also would I better off with an AMR 300 or 500 ? Only want to push 5 to 8 pound, nothing crazy. Also carby choice to accommodate extra air if anyone knows what to use.

Thanks in advance :D
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Brayden
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Suck or blow setup for the charger? Also, budget?
F8B EFI turbo - Three pots and a snail.
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XiT
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Most likely will be carby blower intake. So believe that's suck. Seems the easiest way to go with it really. Budget isn't bothering me as I have to save up after the rebuild anyway. Cost only determines how long I wait to do it.
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Brayden
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Assuming you can get the timing sorted then a stock motor will handle 5PSI no worries. You don't even need to upgrade the clutch.
AMR 300 is fine, but you might have trouble positioning it for a draw-through setup. Ideally the carby needs to be higher than the charger, which needs to be higher than the intake ports to prevent fuel pooling. 30DIC weber seems to be the most popular upgrade for F8Bs, and there's no reason that it wouldn't work for a draw-through turbo.

FYI: Malpassi are the only manufacturer of carby turbo fuel regulators that I have come across, and I would also recommend upgrading fuel lines. The stock return line is tiny!
F8B EFI turbo - Three pots and a snail.
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arklan
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How much hp increase would 5psi give?
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XiT
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I don't mind the carby hat poking through th lid seems it has a scoop anyway. Bonnet already has a hole in it. So hopefully that makes it a bit easier :p 5 psi is all I really want so that's awesome :D
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TurboKat
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Joined: Sat May 04, 2013 1:32 pm

'5 PSI is all I want"
:snigger:
That's what we all say! 
Trust me, you'll be bored with 5 PSI in a month, then you'll be 'I'll just swap the pulley & try it with 8'... then it'll be 10... then 15, etc.
Boost is an addictive drug.  :thumbup1: There's no such thing as too much.
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Brayden
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arklan wrote:How much hp increase would 5psi give?
Depends on the starting point (F5A or F8B) and how well it is set up. Assuming an F8B tuned really well, I'd say roughly 35kw ATW. That's ~50% increase over N/A, and double a stock F5A.
The snot rocket put out 45kw ATW on an emissions test (fuel & igniton maps wound right back) at 8PSI.
F8B EFI turbo - Three pots and a snail.
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86BOY
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Location: Bundaberg Queensland

My EFI F8B got a tune on 5psi wastegate pressure which pushed out 34kw ATW, wound the boost up to 8psi and made 41kw ATW. 5psi is great compared to an N/A setup and I felt a hell of a difference going to 8psi that I wish I went up to 10psi :snigger:.  
Boosted F8B Pocket Rocket.
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