FI intake piping upgrade?

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v6spider
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Your car is a: 4.3L V6 Powered 1972 124 FIAT Spider
Location: Mount Vernon WA

Re: FI intake piping upgrade?

Postby v6spider » Fri Dec 04, 2015 1:10 am

TimpanogosSlim wrote:
You think crapper pipe isn't designed to flow? It's a cornerstone of civilization that it flows. The transitions and bends in modern household DWV plumbing are far smoother than most factory intakes and exhausts.

Anyway if you can get an inlet closer to the front of the car, for a ram intake, that may help a bit.

I still say that the air meter is the choke point. And since the air filter is integral to the meter housing (exactly like the 1992 vw cabriolet i have been painfully burning so much time on lately, fwiw), I don't see an easy or cheap way around it.

There are MAF conversions for porsche engines with a similar bosch air meter, but i suspect that most of those porsche engines are bigger than 2L, so they wouldn't have a direct application on a spider.

Never said it wouldn't flow OK but.. Ideally a mandrel bent tube out of stainless or aluminum would be the way to go. The cool thing about the plastic is it stays cooler. And the chrome reflects heat.. I think for flow the one piece approach would be best for the tube. I agree the airflow meter is probably restrictive as well as the air intake plenum itself. But going bigger also means a possible loss in low RPM streetability. If someone has attempted that modification I would certainly love to hear how it worked out. I did a similar modification on my Toyota 4runner I installed the spectre pipe with kn filter and installed a bigger airflow meter from a 7mge v6. I had to richen the mixture because of the larger airflow meter.. Mileage suffered but performance on the top end went way up.
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4.3L V6 Powered 1972 124 FIAT Spider

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RRoller123
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Re: FI intake piping upgrade?

Postby RRoller123 » Fri Dec 04, 2015 8:55 am

Just a thought for the masses to consider: It seems that laminar flow would be a disadvantage after the AFM, as there is desired homogeneous mixing going on in the intake manifold. So maybe this partially explains why the original rubber tubing is so convoluted? Smoother may just not be better. Just a thought for the various Fluidics Engineers in the group.
'80 FI Spider 2000
'74 and '79 X1/9 (past)
'75 BMW R75/6
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/STD BED
2002 Edgewater 175CC 80HP 4-Stroke Yamaha
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2003 Jaguar XKR
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TimpanogosSlim
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Your car is a: 1977 124 Spider

Re: FI intake piping upgrade?

Postby TimpanogosSlim » Sun Dec 06, 2015 12:20 am

RRoller123 wrote:Just a thought for the masses to consider: It seems that laminar flow would be a disadvantage after the AFM, as there is desired homogeneous mixing going on in the intake manifold. So maybe this partially explains why the original rubber tubing is so convoluted? Smoother may just not be better. Just a thought for the various Fluidics Engineers in the group.


I don't know. Direct injection engines seem to have advantages over port injection and throttle body injection. It may be that there is an abundance of forces for mixing fuel and air regardless of improvements in airflow into and through the manifold.

I've been told that Formula 1 throttle bodies have taken on a format more like a camera shutter, because that makes more power than rotary butterfly valve throttle bodies. That could be strictly because of the lack of a big vane in the tb at WOT.

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RRoller123
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Your car is a: 1980 FI SPIDER 2000
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Re: FI intake piping upgrade?

Postby RRoller123 » Sun Dec 06, 2015 7:36 am

Interesting. It occurs to me upon further thought that the butterfly vane at the throttle body breaks up any laminar flow anyway, and probably very well.
'80 FI Spider 2000
'74 and '79 X1/9 (past)
'75 BMW R75/6
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/STD BED
2002 Edgewater 175CC 80HP 4-Stroke Yamaha
2003 Jaguar XK8
2003 Jaguar XKR
2021 Jayco 22RB
2019 Bianchi Torino Bicycle


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