Intake modification

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Makaveli_600
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Intake modification

Post by Makaveli_600 »

hey, im planning on putting a new intake system into my fto. My goal is to make a custom air intake, adapt the largest TB as possible and modify the stock manifold.
My question is what is the best way to modify the stock manifold for more performance, port and polishing, boring? Could anyone give me any advice weather this is worth doing, places that will do it, cost, etc.
any information will be great help. Thanks.
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Bennoz
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Post by Bennoz »

So I take it you've done up the exhaust with a high flow cat & upgraded the collector pipe, now looking for more power? Cause there's no point doing all the work on the engines breathing if it cant be exhausted.

If you have, then great go for it. The intake manifold comes in 2 parts, a lower section (bolts direct to the heads) and the upper section (has the TB bolted to one end of it.) You have to port both sections & try to match port the join between them. There is a fair bit of meat that can come out. Years ago we actually had some figures come back from one of the shops that did a port job. Figures are per runner, also used was a 63mm throttle body:

BEFORE POWER PORTING WITH STD THROTTLE BODY
1. 197 cfm
2. 200 cfm
3. 196 cfm
4. 192 cfm
5. 197 cfm
6. 200 cfm

TOTAL: 1182CFM

AFTER POWER PORTING WITH LARGER THROTTLE BODY UPGRADE
1. 220 cfm UP 23 cfm
2. 224 cfm UP 24 cfm
3. 220 cfm UP 24 cfm
4. 218 cfm UP 26 cfm
5. 219 cfm UP 22 cfm
6. 220 cfm UP 20 cfm

TOTAL: 1321 CFM

AVERAGE INCREASE PER RUNNER 23.6 CFM.
TOTAL INCREASE 139CFM.
TOTAL INCREASE 11.76%.

Keep in mind, the TB upgrade alone gives almost more than half of that increase. It was a standard TB ported out to 63mm. If you go any bigger than that, there are other complications you'll come across with the rear lip of the assembly.

For all your machining needs, you'll need to find an engineering shop. I had my TB done by a bloke in Brookvale. He only charged me $80 for the bore job & $25 for the new 63mm brass butterfly. The port work on the intake will cost you more thou, I'd estimate somewhere in the vicinity of 3-500 bucks.

From the TB outwards, its a matter of making up a nice free flowing pipe. Have a search on here, there are a million different incarnations that people have come up with over the years. I used 2 x 75mm 90 degree bends of Monza silicon pipe for instance - then wacked a unifilter on the end of it & bingo, an extra 7kws at the wheels.
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Makaveli_600
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Post by Makaveli_600 »

Wow, thanks heaps for the information, is very helpfull.
I am curious to what you said about the TB, so you are saying their is no point going any bigger than 63mm? And which mean theirs no point on piping bigger than say 65mm as you dont want to bottle neck the air flow? On my understanding the aim is to get as much air/fuel mixture into the engine aspossible. I need to learn, so info would be great.
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Bennoz
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Post by Bennoz »

Makaveli_600 wrote:Wow, thanks heaps for the information, is very helpfull.
I am curious to what you said about the TB, so you are saying their is no point going any bigger than 63mm? And which mean theirs no point on piping bigger than say 65mm as you dont want to bottle neck the air flow? On my understanding the aim is to get as much air/fuel mixture into the engine aspossible. I need to learn, so info would be great.
Im not saying there's no point going bigger, its just a little difficult to do on a standard throttle body. If you pull one off & look at the back of it you'll see what I mean ;)
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bushido
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Post by bushido »

Contact details for the brookvale guy Ben! :D
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