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Re: 540 not showing power
Posted: Sun Jun 28, 2020 2:17 pm
by frnkeore
What I should have said is average HP. If you can't pick up average HP when modifying a engine, it's very hard to go faster.
If it does, indeed have more high rpm HP but, the mid range falls off, I think that, that would account for the lower ET and slightly higher trap speed. But, not consistency.
Re: 540 not showing power
Posted: Sun Jun 28, 2020 2:42 pm
by Stan Weiss
Can you post the dyno sheet for the engine with the new cam?
Stan
Re: 540 not showing power
Posted: Sun Jun 28, 2020 3:47 pm
by sjre
As soon as I can get more info I will post back.
Re: 540 not showing power
Posted: Sun Jun 28, 2020 4:01 pm
by mt-engines
sjre wrote: ↑Sat Jun 27, 2020 7:16 pm
Local builder refreshed 540 only change was cam. Dyno showed 740 at 6200 , 620 tq 4700. the problem is car went 9.70 at 135 last year 9.90 at 136 best this year .
This year very inconsistent all over the map.Swings as much as 5 tenths.Mph is up a little but crazy. This motor after refresh made more power. combo is 540 11.0-1 comp dart 345 no porting victor single plane comp 272-280@50 737/710 lift 5500 converter th400 4.10 gears 3200 lb car.Old cam 260-270 112 both solid rollers.
Trans and converter fresh as of last sept. Questions are
why peak at only 6200 with 345 heads and why so inconsistent ? Could the cam change affect it that much? Builder said he uses this cam on his street 540s.Could the converter have gone bad? Engine also likes less ign timing than before.60 ft still the same around 1.37
Thanks for any ideas
without seeing the dyno sheets it is just a guess. and still could be.
how big is the carb? was it going rich, lean etc.. was the timing pointer moved? did you try timing on the dyno?
Re: 540 not showing power
Posted: Sun Jun 28, 2020 4:15 pm
by steve cowan
At that cubes it shows 1.15ft/lbs per cube,
1.37hp/cube
It picked up 1-2mph so in theory it made a bit more power,a cam change really does not mean much unless original cam was way wrong but I doubt it was.
I have run 134 mph @3150 pounds with less cubes,comp,and cam.
On the calculator the 540 shows 640-650 hp.
Re: 540 not showing power
Posted: Sun Jun 28, 2020 4:35 pm
by skinny z
skinny z wrote: ↑Sun Jun 28, 2020 10:54 am
sjre wrote: ↑Sat Jun 27, 2020 7:16 pm
New cam. 272-280@50 737/710. Old cam 260-270 112
Can you provide full specs for
both cams?
Can you post the dyno graph?
sjre wrote: ↑Sat Jun 27, 2020 7:16 pm This year very inconsistent all over the map.
In addition to the above (and further subsequent requests for dyno graphs) can you explain what the above quote entails? All over the map could mean a lot of things.
Re: 540 not showing power
Posted: Sun Jun 28, 2020 5:32 pm
by sjre
all over the map means 129 to 136 mph et from 9.90 to 10.57
Re: 540 not showing power
Posted: Sun Jun 28, 2020 7:58 pm
by bob460
Should be making peak power near 7000 rpm.........not 6200rpm.
Should be making 800+ hp and 700+ tq something is not right.
Re: 540 not showing power
Posted: Mon Jun 29, 2020 5:24 am
by Monza355
I ran a similar cam as the one you swapped out in a 9.2:1 compression 565 bbc engine with a 325cc Dart Pro1 heads. Super victor intake and a older mode of the 9375 1050 cfm Dominator. The engine ran a 9” 4200-4500 stall converter and liked begin shifted at 6400-6600 rpm’s
It ran a 9.70’s at 138.5 mph in a 3550 lbs Firebird. It ran decent for what it was and a fantastic street engine.
Your 60ft’s are decent. Does the car run smooth down the track or does it seem to lay over at some point ? What does it run in the 1/8 mile ? And what brand and size converter do you run ?
Re: 540 not showing power
Posted: Mon Jun 29, 2020 3:02 pm
by Orr89rocz
Fuel problem? Ignition? If its not repeating and going from 129 to 136 mph It sounds like something is killing power from hit to hit. Bad wires, grounds, plugs? Carb?