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 Post Posted: Sun Jan 15, 2012 5:42 am 
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randy355 wrote:
shrinker wrote:
Did they supply you with a dyno printout?


Yes they did. Was you wanting some info off it?


Yes Im just interested to see how the engines are reacting up the power curve. can you post it?


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 Post Posted: Sun Jan 15, 2012 12:29 pm 
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I can't seem to post pics or attachments???

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 Post Posted: Sun Jan 15, 2012 1:05 pm 
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randy355 wrote:
I can't seem to post pics or attachments???


Did you read this? :-k

viewtopic.php?f=4&t=7171


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 Post Posted: Sun Jan 15, 2012 6:36 pm 
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randy355 wrote:
I can't seem to post pics or attachments???


There is a size limit on this board. I think it's something like 600 X 800. If your pics are bigger than that you will need to resize them before they will post.

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 Post Posted: Sun Jan 15, 2012 10:17 pm 
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I emailed the dyno sheet to Rick to post. I'm not registered at photo bucket or any of those places.
If I did it right it should be on here before too long.

Shrinker, not sure what info your wanting to look at, but I just sent the front copy. Corrected power/oil temp/etc

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 Post Posted: Sun Jan 15, 2012 11:42 pm 
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Here it is.
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 Post Posted: Mon Jan 16, 2012 12:43 am 
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Its just interesting to see these things. See how the fuel lbs per hour just hangs around at the low RPM range below 2900. Above 3200 it starts to rise normally.
See the BSFC is poor below 3200.
See how the torque rises till 3400 then it drops backwards till 4000 then rises again and see how the fuel lbs/hr doesn't drop during that phase where the torque is going backwards. There is still air going into the engine because the lb/hr is telling us its increasing but its not burning the fuel, so you have to figure out why, then you win. The torque at 3300 is the same as at 4100 so whats the hole all about?


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 Post Posted: Mon Jan 16, 2012 9:05 am 
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I wouldn't put much faith in the bsfc numbers. There was some sort of issue with the fuel lines and how it was being metered. I was told it had to do with there being a return line set-up for the EFI engines. This engine had the best BSFC numbers of any I've ran on the dyno, and the owner of the dyno shop where we tested, said they were as good as most of his 18*/15* higher compression engines.

The TQ dip was there on the stuska we did our testing on until we went to tryY headers, then the dip was for the most part gone, but the TQ curve was flat through that part of the rpm range so clearly there is something different about the loading of the dynos or the inertia factors.

Almost every engine there had a dip in the TQ curve somewhere below 4000 rpm. The dts seems good at showing dips in the TQ curve, or maybe other dynos seem good at hiding them.

A dip in the TQ is no indication of how an engine will place in the competition. The SAM engine had the worst dip of any and they finished first. On the dyno their engine sounded like it was going to die at about 3200 rpm, and the graph showing the TQ curve looked almost vertical down, then up.

Yea we can say IF that dip was gone we'd have won, or the SAM engine would have scored better, but in the real world getting rid of that dip would have meant trading TQ off the peak for TQ down low resulting in a worse score.

Going in to this deal I felt our team weakness was valve train knowledge, but now I beleive it was probably lack of past dyno experience. I've only been in on about 10 dyno sessions, and half were on this engine.

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 Post Posted: Mon Jan 16, 2012 5:46 pm 
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Thats interesting comments about the Dyno. Seem to me to be a basic requirement to at least measure things correctly and not compromise a carby setup for something that may be related to EFI.

Is it a clear objective of the EMC to eradicate carburetion from the contest maybe?

I also wonder if the dip in the torque curve is an artifact of the dyno rather than a feature? If everyone was experiencing the same thing its seems a bit unusual. Your description of the SAM dip is very unusual and raises my eyebrows with a question of the dyno system and the validity of the whole contest.
Thanks for posting that.


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 Post Posted: Mon Jan 16, 2012 5:48 pm 
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randy355 wrote:
This engine had the best BSFC numbers of any I've ran on the dyno, and the owner of the dyno shop where we tested, said they were as good as most of his 18*/15* higher compression engines.


For example what was the BSFC reading on the testing dyno you used?


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 Post Posted: Mon Jan 16, 2012 8:08 pm 
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What type of dyno was it. inertia or brake?
I've only ever seen one DTS control here so far that Ive used and it was on a Stuska water brake. It doesnt hold the engine RPM to a constant ramp speed, it allowed the engine to accelerate like it would on an inertia dyno then measured the time and printed out a result. It had to have inertia compensation to do that. I'm not so sure about the usefulness of having lots of things to compensate for.
The first thing I noticed when using this particular dyno was the plugs didnt read anything close to what they do in a race. The room was fine, and all that stuff with air etc was ok, but the plugs are truth and Ive not seen plugs on a superflow be vastly dissimilar to the track. Interesting stuff. I may get to the bottom of it one day.


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 Post Posted: Mon Jan 16, 2012 8:14 pm 
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Shrinker, I think EFI does get some preferential treatment in the rules because of sponsors. One year carbs had to run dual plane intakes. It's their contest so they can set the rules and I can not apply if I don't like the rules.

The Bsfc numbers where we tested were averaging aounnd .400 for the pull as a whole.
The fuel flow was 85 LBs per Hr. at the start, and 260 LBs per Hr peak and an average of 157 LBs per Hr on the dyno where we tested. I just pulled up the file and grabbed a pull, it was pull # 82 so it would have been a little more than half way through our testing. The pull at the EMC shows 128 LBs per Hr at the start of the pull vs 85 on our dyno sheet. Some of that fuel was being returned to the tank. I think the problem at the EMC was having a fuel pump capable of producing the pressure for the EFI set-ups couldn't be dead headed to regulator at 6.5 LBs for a carb, they needed a return line.

The fuel flow on the dyno we tested on goes flat along with the TQ curve, so I trust it mush more than at the EMC.

Acording to the dyno sheet listed in Popular Hotrodding the SAM engine had a 200LB dip in the TQ curve.
It lists;
2900-554.3
3100-552.6
3300-346.5
3500-539.7
3700-529.5
4100-560.4


They only show every other reading in the magazine so that's why I left out some, but you get the idea.
Being there I can say it sounded like a 200 LB dip. I'm betting there wasn't a 10 Lb dip after the first dip, but the dyno trying to get the accelration rate under control.

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 Post Posted: Mon Jan 16, 2012 8:17 pm 
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shrinker wrote:
What type of dyno was it. inertia or brake?


It was a brake type of dyno. It does let the engine accelerate faster through peak TQ, but not as much as the stuska we tested on. At the EMC the AVERAGE acceleration rate for whole pull was about 400 RPM per sec.

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 Post Posted: Mon Jan 16, 2012 8:33 pm 
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WOW thats very interesting isnt it. There is no way that engine could have a real 200 lb dip without it being a completely idiotic construction. You heard the dip or something wrong so its likely your correct, its not a typo in the magazine is what Im getting at. I just cant believe it would be true for an engine to be that bad to actually do that extent of torque change. There has to be something possibly wrong with the dyno system and thats not fair for competition is it.
If your engine performed how you said on your own testing then I think that would be true of a well developed engine which is whats to be expected of someone entering that contest. I think your engine is a good thing.


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 Post Posted: Mon Jan 16, 2012 9:24 pm 
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I remembered SAM's engine having a dip too but I didn't think it was 200ft/lbs.

I looked at some pics I took of the score monitor and I happened to have the SAM pull Randy was posting numbers for and it wasn't 200lbs low. That was a typo. These numbers were directly from the scoring monitor at EMC. Still it dropped 30lb/ft from 3000-3800 rpm.

We knew the dyno we were testing on had a couple issues, mostly in controlling rpm when it came out of the mud at 2500 rpm and came onto the tq curve it didn't keep the accel in check. I don't think when it is accelerating at 1500-2000 rpm/sec it is getting valid readings. Even at speeds when the accel was slow the corrected torque was ~ 5-10lbs higher than the DTS at EMC.

This is one of the qualifying pulls of the SAM 435ci CHI headed Ford.
Code:
RPM      CTORQUE
2500     536.9
2600     544.8
2700     552.4
2800     554.4
2900     554.3
3000     556.2
3100     552.6
3200     548.5
3300     546.5
3400     544.0
3500     539.7
3600     535.0
3700     529.5
3800     528.8
3900     535.9
4000     547.1
4100     560.4
4200     574.2
4300     587.8
4400     598.8
4500     606.1
4600     612.0
4700     615.3
4800     617.7
4900     618.1
5000     618.7
5100     618.4
5200     617.6
5300     616.8
5400     615.3
5500     612.8
5600     609.2
5700     602.7
5800     597.0
5900     590.0
6000     584.3
6100     578.8
6200     573.3
6300     567.3
6400     561.5
6500     554.2


Rick


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