Single point injection carb replacement

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ps2375
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Re: Single point injection carb replacement

Post by ps2375 » Sat Mar 04, 2017 3:22 pm

What was the HP at the wheels? Any signs of icing? Did you make any cylinder to cylinder comparisons to determine what fuel distribution was doing? What are other specs of motor?

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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sat Mar 04, 2017 3:56 pm

Didn't do a rear wheel test but it'd be about 65-70. The manifold got pretty cold with some condensation.
No comparison done and no need to do a cylinder comparison
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ps2375
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Re: Single point injection carb replacement

Post by ps2375 » Sat Mar 04, 2017 6:12 pm

How did you not do a "rear wheel test", it was in the car on the rollers....at least it appears to be if the vid is to be believed. As the dyno will read in Wheel HP and then use some form of conversion to get crank/flywheel HP, and not all vehicles have the same drive-line losses(but can be close).

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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sun Mar 05, 2017 3:08 am

Of course it will measure rear wheel hp and produce graphs of rear wheel hp but for this sort of thing I use the weather station correction and produce graphs of flywheel hp/torque.
Here's two graphs of a stock 2 litre type 4 with w twin Solex which VW claimed 70 flywheel hp the wheel hp figures are irrelevant as we wanted to compare to the factory numbers which are always given at the flywheel
Image
Image
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ps2375
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Re: Single point injection carb replacement

Post by ps2375 » Sun Mar 05, 2017 10:54 am

I understand weather correction, but how do you know that your conversion to flywheel hp is even close from the wheel hp numbers? How are you calculating drive line losses?

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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sun Mar 05, 2017 11:25 am

Flywheel power numbers concur with OEM manufacturers numbers and also injector flow rates match up good which are two pretty good indicators but as you should know it's all about comparative numbers before and after changes
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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sun Mar 05, 2017 12:05 pm

Here's a good one I forgot about 1300 single port rebuilt completely stock except for an aftermarket exhaust showing 44hp flywheel
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ps2375
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Re: Single point injection carb replacement

Post by ps2375 » Sun Mar 05, 2017 12:56 pm

So, your graphs are adding about 12-15% to the actual wheel numbers?

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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sun Mar 05, 2017 1:15 pm

Does it really matter ?
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ps2375
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Re: Single point injection carb replacement

Post by ps2375 » Sun Mar 05, 2017 2:01 pm

I'm just curious how close you are or aren't to an actual flywheel number. I know every dyno will give it's own number and as you stated earlier that the change is all that really matters. But when someone has a chassis dyno setup giving flywheel numbers, I get curious. That's all.

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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sun Mar 05, 2017 3:02 pm

I gave examples of my flywheel readings v OEM which is all I can do to verify the accuracy of the readings Now this is the last readouts I'm giving after which maybe you could start a new thread on the Samba about dynos
Porsche 996 factory claim 295hp flywheel
Image

Porsche 911 3.0 factory 210 hp flywheel
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ps2375
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Re: Single point injection carb replacement

Post by ps2375 » Sun Mar 05, 2017 3:48 pm

Sorry, not trying to upset anyone.

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Paul H
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Re: Single point injection carb replacement

Post by Paul H » Sun Mar 19, 2017 2:38 pm

As promised the latest test of a 45mm twin choke throttle body on a Bugpack manifold also high mount injector test
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Clonebug
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Re: Single point injection carb replacement

Post by Clonebug » Sun Mar 19, 2017 4:39 pm

Very interesting results Paul!!!
One hp difference between single IDF and Single 42 TB.
Big difference between dual TB's.
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Re: Single point injection carb replacement

Post by Piledriver » Sun Mar 19, 2017 4:47 pm

Possibly cylinder to cylinder variations due to fuel distribution with the centermounts.
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