Look at this dyno graph and let me know what you think
02-04-2013, 07:56 PM
#1
Look at this dyno graph and let me know what you think OK so in October last year I got the car on the dyno at a dyno day. I made 3 pulls (Sorry I didn't get to log any of them) 1 on waste gate pressure (6.5 psi) and 2 on 14 psi
You can see it in the low boost pulls but it is the most obvious in the high boost pulls. The car laid over had at 5500rpm it could be felt in the car on the dyno (I can not feel it on the street or at the track). I did after this dyno day find the ground on the back of the drivers head was loose. But the car also ran 8.8 like this.
I plan to get the car on the dyno early this year and try and track down the issue. But places to start would be good. I will add. I had TR6 plugs on this dyno day. But had a similar looking low boost dyno graph with BREF7 plugs but I also had my Alternator die then.
Plugs were gapped around .022 AFR was around 11.5-11.6 on E85 and and 21 degrees of timing.
Let me know if you need anymore info
You can see it in the low boost pulls but it is the most obvious in the high boost pulls. The car laid over had at 5500rpm it could be felt in the car on the dyno (I can not feel it on the street or at the track). I did after this dyno day find the ground on the back of the drivers head was loose. But the car also ran 8.8 like this.
I plan to get the car on the dyno early this year and try and track down the issue. But places to start would be good. I will add. I had TR6 plugs on this dyno day. But had a similar looking low boost dyno graph with BREF7 plugs but I also had my Alternator die then.
Plugs were gapped around .022 AFR was around 11.5-11.6 on E85 and and 21 degrees of timing.
Let me know if you need anymore info
02-04-2013, 08:19 PM
#5
Well at the track I am only below 5500rpm in 1st gear and it pulls so hard and so quick that I just can't feel it. The car only drops 1000 rpm on the shifts so it drops from 6700 rpm to 5700 rpm.
Also hooking my car at 14 psi on the street doesn't happen
Also hooking my car at 14 psi on the street doesn't happen
02-04-2013, 09:39 PM
#6
What you are seeing is the effect of a large stall converter on the dyno. All of the pull before 5500 is just converter slip. When it finally catches it is showing you what you are actually making. On the low boost pull, the converter is grabbing much sooner.
Ryan
Ryan
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02-05-2013, 06:13 AM
#8
No graph of boost They didn't have a sensor for that there and I forgot to log the pulls.
But to do know at the track in 1st gear the car sees full boost before 4400rpm
I am just suprised that my 3400 Yank Stall goes that high graphs from a friend didn't look like that with the sae stall
But to do know at the track in 1st gear the car sees full boost before 4400rpm
I am just suprised that my 3400 Yank Stall goes that high graphs from a friend didn't look like that with the sae stall
02-05-2013, 07:08 AM
#9
If it goes 158 and the graph looks like that I wouldn't even think about the dyno numbers. I have had cars that have had ugly graphs that can have you chasing a problem that does not exist. Just to bring them to the track and have them run like an animal. Oh and for what it is worth I never had a high hp car with a yank converter show good dyno numbers. If you try to lock it at WOT like a Precision converter it will likely be junk afterwords.
02-05-2013, 09:07 AM
#15
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Lock up the converter and the results will be a LOT better.
02-05-2013, 11:03 AM
#20
With a T400 you always plot by mph, not rpm. Shows what going on. Then if it's a non-loaded dyno the boost can drop in the higher rpms because the roller is just free wheeling.
Here is mine by mph, nice long pull. Too bad the converter couldn't take it.
Here is mine by mph, nice long pull. Too bad the converter couldn't take it.