gt2871 dyno
#7
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The bottom end just has eagle rods, stock '95 pistons and rings, 99 head is completely stock, stock intake manifold, BEGI cast exhaust manifold, GT2871 .64AR.
I've certainly seen better numbers from others on the same turbo, but I'm more than content.
The weird little midrange dip has me a bit concerned, I'm wondering if I'm past MBT since that was probably the most advanced are in my spark map compared to others I've seen. I'm going to pull a few degrees between 4900 and 5500. I'll post the spark map in a few min.
The low (red) line is what I daily, 285hp, 270tq
I've certainly seen better numbers from others on the same turbo, but I'm more than content.
The weird little midrange dip has me a bit concerned, I'm wondering if I'm past MBT since that was probably the most advanced are in my spark map compared to others I've seen. I'm going to pull a few degrees between 4900 and 5500. I'll post the spark map in a few min.
The low (red) line is what I daily, 285hp, 270tq
Last edited by pdexta; 05-07-2011 at 03:04 PM.
#9
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They were doing a dyno day so it was just a pull. I just installed new injectors not long ago and the fuel map definitely needs a little more loving. I'm sure there's a good bit left in it with a real tune.
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Here's the video, pretty uneventful:
Here's the spark map I was using at the time of the dyno:
And I pulled a couple degrees... If someone has advise on this I'm certainly open to opinions, timing may not even be the issue, it was just the first thing that crossed my mind.
Here's the spark map I was using at the time of the dyno:
And I pulled a couple degrees... If someone has advise on this I'm certainly open to opinions, timing may not even be the issue, it was just the first thing that crossed my mind.
#11
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You run much more timing then me up top. I never realized how low I had mine set. I am going to try a similar timing map as yours up high and see how my built motor does.. I will try to get a log on my 2871 so we can compare.
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????
Your 2300-3400 cells look pretty aggressive but hey if it's not knocking that's great.
Up top though, you are pretty far from MBT. I am at 22*@200kPa@7000RPM which is at least 4* short of MBT. My tune is safe because timing can ramp with engine speed because the piston is traveling faster and there's less time for fuel to burn.
I think that you have a lot left on the table.
Your 2300-3400 cells look pretty aggressive but hey if it's not knocking that's great.
Up top though, you are pretty far from MBT. I am at 22*@200kPa@7000RPM which is at least 4* short of MBT. My tune is safe because timing can ramp with engine speed because the piston is traveling faster and there's less time for fuel to burn.
I think that you have a lot left on the table.
#13
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Up top though, you are pretty far from MBT. I am at 22*@200kPa@7000RPM which is at least 4* short of MBT. My tune is safe because timing can ramp with engine speed because the piston is traveling faster and there's less time for fuel to burn.
I think that you have a lot left on the table.
I think that you have a lot left on the table.
#16
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319hp, 292tq the 2nd time around. It was a good bit cooler, so tough to tell what the differences were until I can overlay the graphs. They were using a 1.1 correction factor, so numbers shouldn't be significantly lower than other dynos.
#17
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I just got back from trying out your conservative spark table on my 2871 and holy ******* shitballs I picked up a ton of top end power. Mind posting a log or screen shot of your car in the 1:1 gear?
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Here's the dyno from the 2nd time around:
Ambient temps were probably 20 degrees cooler the 2nd run and humidity was way down as well which makes the number pretty much irrelevant.
Timing for the 2nd run:
I pulled a little timing from the midrange and added some up top for the 2nd run. That stupid midrange dip got worse but it held power better up top. After overlaying the dyno charts to look at the tq curve the first run looks better up to 5400 and the 2nd run was better above that. With those results the timing is going back to the original map in the 5200 and 4600 columns and staying the same above that.
Thanks for the advise guys, especially Fae, you definitely gained me a few hp.
I like to think that I'm a pioneer of the poor mans dyno tune.
Ambient temps were probably 20 degrees cooler the 2nd run and humidity was way down as well which makes the number pretty much irrelevant.
Timing for the 2nd run:
I pulled a little timing from the midrange and added some up top for the 2nd run. That stupid midrange dip got worse but it held power better up top. After overlaying the dyno charts to look at the tq curve the first run looks better up to 5400 and the 2nd run was better above that. With those results the timing is going back to the original map in the 5200 and 4600 columns and staying the same above that.
Thanks for the advise guys, especially Fae, you definitely gained me a few hp.
I like to think that I'm a pioneer of the poor mans dyno tune.