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#1
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Vacuum pump on Dyno
Hi Folks: What's the consensus. Vacuum pump use on dyno.
Do we use it right from the start, or do a couple of pulls without it, then connect it after rings are seated? Ok, I see I posted this in June, Sorry for the duplicate. Could not delete. Thanks Last edited by chuckies76ta; 10-29-2020 at 04:42 AM. |
#2
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Unless you will be breaking in a flat tappet cam I would run it right from the start.
Get the motor confirmed to be sound and do 5 pulls with it running and average those out and then do 5 pulls without it , then average those out , and on all ten pulls try your best to keep the oil temp seen within 20 degrees .
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#3
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Thanks Steve. It's a Solid Roller Cam,. 505 Cu In. IA2 block. It goes on the dyno tomorrow. Pretty excited.
Thanks |
#4
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Quote:
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#5
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Rings usually seat within 5 pulls. We run the timing a little low and hot lap it till it stops increasing in power then tune from there. We can generally make around 20-25 pulls in a day.
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#6
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Thanks John.
Charles |
#7
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We won't do any pulls without the vacuum pump working as we don't have a PCV system installed. My main concern is during initial startup when it's a crucial time for the rings to seat.
Thanks Charles |
#8
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So your absolutely sure the numbers are not a fluke!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#9
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What are the engine specs?
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#10
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At $500 to $1000 a day for dynoing, 10 pulls is a huge waste of time.
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#11
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John finally dyno'd my 505 with the new cam two weeks ago at Westside Performance in Houston, cost was $650 for the day. He arrived at 9:00 AM and by 11:30 they had made 13 pulls. Went to lunch, came back and made three more. A total of 16 pulls. No equipment testing, like intake manifold changes, carbs or carb spacers. Engine break-in, lash changes and jet changes only. This was not John's first rodeo at set up, it didn't take him long to set up the engine on the dyno cart, plus he had a mechanic friend helping.... not me
.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE Last edited by Steve C.; 10-29-2020 at 01:36 PM. |
#12
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Well what did it make? We want to know?
GT. |
#13
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I don't want to muck up Charles thread too much, but I guess he got his answer regarding the vacuum pump. So in short....
Depending on the pull, it's now a 625-630 HP engine. The best number was 635 HP. Peak torque at 4400/4500 rpm and peak power at 5700/5800 rpm. Start of the recorded numbers at 4100 rpm the torque was 627/628 ft.lbs. It carried over 600 ft.lbs torque from 4100 rpm up thru 5400/5500 rpm. The new cam has the same .050" duration but less .200" duration and less lobe lift. The goal was to reduce the cam profile intensity in order to significantly reduce my valve spring pressure. Tim at Bullet Racing Cams was expecting about a 20-25 horsepower loss at peak power, it was a bit more. Other factors, but my lower net valve lift is not taking advantage of the cylinder heads. Peak power with the previous cam was at 6000 rpm, I won't notice much difference in that arena for a street car. So I'm OK with it.
__________________
'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE Last edited by Steve C.; 10-29-2020 at 05:29 PM. |
#14
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Steve: Don't worry about posting, it's all good.
Charles |
#15
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Quote:
The dyno is never a waste of time. It's pretty much a must on a new build. Charles |
#16
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Completely agree! I said wasting 10 pulls on just the vacuum pump is a waste of time.
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#17
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Quote:
Ok, Sorry, Misunderstood. Charles |
#18
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The most accepted way of dyno testing for a accurate change in engine power is to make 5 pulls, then you toss out the best and the worst pull and then average the remaining 3.
If you don't see the value in that for accuracy sake then your beyond help!!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#19
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Quote:
If the dyno operator is good and the dyno is maintained properly then it should be repeatable (within a horsepower or so) that is plenty good to see what a chance does. This isn't NASCAR or ProStock where we are looking for 1/2 a horsepower. Sorry but your method just isn't practical for 99.9% of people dynoing |
#20
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My 455 in the TA, 500 IA and 470 /409 we made between22 -25 pulls in a day. 455 was on a Stuska dyno other Superflow.
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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