Wouldnt it be great to see some dyno videos with results.I start off with this race V12
Best regards
Ole Mobeck
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And this is a std HE engine
Best regards
Ole Mobeck
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Thank you very much for that, Ole!
It’s great to see actual numbers from someone doing real dyno work. I also noticed that that is all accomplished with nothing fancy on the intakes: no horns no anything.
Yep Paul.
Standard throttles also, no bigbore.
There was only -0.4 psi vacum in the manifold at 7500 rpm so not much need for larger stuff.
I tryed with ba bellmouth but no change, its the heads that is maxed out, the limit is there, with the STD size Gr.A style valves.
Ole m
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Interesting: Similar results are why I rail against standard engines being over-carbureted, like putting a 750 cfm Holley, on a SBC.
Gee, I would consider -0.4 psi a lot.
Carbs and EFI are different in this regard. Too much carb makes an engine run lousy. Great big butterflies on an EFI system might make the throttle a bit twitchy – just touch it and you get too much – but the engine should run just fine. Gotta recalibrate the throttle pot, of course.
That’s only .8” of vacuum, virtually no restriction. Pretty darn good for a normally aspirated engine without modifications to the throttle or intake.
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I mean the original throttle rod arrangement is way to progrssive (in the start) for a race engine, so I changed the geometry a bit. This way the tps signal will be more equal to the actual movement of the butterfly, and the mapping of the ecu will be better and also drivability of a racecar.
This relationship also alters with bigger throttles. But now My engine actually opens the trottles a bit from zero to 15% tps actuation. From std they do not.
Just my input on this
Ole M
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Roughly what, 3%? I agree, probably pretty good as normally aspirated engines go. But if you could get that vacuum down to, say, 1%, you’d have gained 2% power with virtually no downsides other than the cost and effort to make the mod. Of course, I dunno how hard it would be to get it down to 1%.
You can with a tuned intake and scavenger exhaust, and cam changes (if the stars align) but nothing is free, the engine might get slightly over 100% volumetric efficiency at one rpm, and be less everywhere else.
Great for boats, not so much cars.
Like operating a business, cutting 5% out of your cost is easy; the next 5% is 10x harder. In the case of chasing horsepower, 10x the cost.
When people would ask me how one could get 70hp out of a bone-stock VW 1200, I’d tell them…
-40 to 50 hp, $1500
-50 to 60 hp, $1500 more
-60 to 70 hp, $75/hp.
(All prices 1984 vintage!)
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Or, as a popular poster puts it:
Powerful
Reliable
Cheap
– choose any two.
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