Engine dyno info help

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tjs44
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Engine dyno info help

Post by tjs44 »

Since we lost Big Joe,my dyno go to guy is gone.I just built a short deck 383 pontiac with a set of RA V tunnel port heads,flo 315 at 600 with the large ports with the pushrod thru the port but the factory wings were put in to help reduce some port vol.Im sure its going to drive fine with the single 4 holley as I have built a couple of them allready..My issue is I have a factory 2-4 Xram intake with a set of the Z28 Xram holleys.I have O2 sensor avail in all 8 header tubes.Can I put it on a engine dyno and put a light load on it and learn anything running it between 1500 and 3000 on fuel distribution to guestimate how it will drive on the street?5 speed Tremic 500 with 3.27 first gear with 3.31s in the back.I know Westec is setup for all 8 O2s.Tom
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MadBill
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Re: Engine dyno info help

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You wrote "O2 sensor. Sure, but if you have only one it will take some time. If you have eight, light throttle A/F distribution would be useful but WOT data would be more crucial.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.
tjs44
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Re: Engine dyno info help

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Yes,all 8 bungs are installed in the headers and im told Westech is setup to use all.I would like to just have a good feeling before I spend the money that I can learn something.Hate to put it in the car and find out it sucks in part throttle driving.Tom
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Re: Engine dyno info help

Post by David Redszus »

tjs44 wrote: Sat Sep 25, 2021 11:38 am Yes,all 8 bungs are installed in the headers and im told Westech is setup to use all.I would like to just have a good feeling before I spend the money that I can learn something.Hate to put it in the car and find out it sucks in part throttle driving.Tom
A lambda sensor for each cylinder is the ideal. The difference in readings across the rpm band and throttle
position will surprise you...and maybe disappoint you.

For street, road racing, and short oval, much can be learned from mid-range rpm and partial throttle.
The best set-up would be to feed rpm, TPS, and lambda into a data logger that can be downloaded to a
laptop for further analysis.

And then take it to the street and be amazed how different the readings are compared to the dyno.
tjs44
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Re: Engine dyno info help

Post by tjs44 »

Westec has all the right stuff,as many know the 69 SCCA season allowed multi carbs.The short deck 303 was outlawed as they only made 25 engines.When they had to try to use a std deck 10.2 engine they were pretty much not competitive with any head package.I know there was only a couple handfull of the 2-4 Xrams made for both the Dport and tunnel port short deck and when abandoned all R&D went away.At least this engine is 383 CI instead of 303 so I hope it will be friendly to drive.Once the engine gets in the car it will almost never see RPMS over 3000 so the 1500-3000 is where I would like to tune to.Thanks
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