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Old 07-16-2004, 10:02 AM   #1
MadMax
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Join Date: Apr 2000
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Location: Danbury,CT <- Center of Univer
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Wink Help explain engine curve

Ok im doing lots of research on my dyno numbers. I found several fomulas, but they seem to all be linear. meaing at 6250 rpm they seem to be close to show HP/TQ, but between the rpm range it is linear, even though my dyno plot shows a curve. What cause that curve? Is it the VE of the engine at the rpm range?

Here are numbers
rpm hp - dyno
2450 72
2900 88
3350 108
3800 128
4250 140
4700 148
5150 154
5600 142
6050 140

here is from a fomula
RPM HP Curve
2450.00 85.346
2900.00 106.532
3350.00 127.718
3800.00 148.904
4250.00 170.09
4700.00 191.276
5150.00 212.462
5600.00 233.648
6050.00 254.834
6250.00 264.25

Any engine guru' please enlighten me.

Thnk,
mm
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Old 07-19-2004, 12:14 PM   #2
MadMax
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bump, anyone have a clue what im talking bout? lol

MM
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Old 07-19-2004, 07:12 PM   #3
jsaunders
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theres a curve because the engine "works" up the the hp/tq rating, even though it seems linier at the points on the rpm/hp scale ie. going from 2500 (125 hp) to 3000 rpm(175 hp) you get 2 different hp numbers. YET the engine is still making power inbetween 2500 -3000. I hope this helps. Or maybe I don't understand the ???? Joel
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Old 07-20-2004, 09:08 AM   #4
MadMax
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Location: Danbury,CT <- Center of Univer
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2000 MY00 SRP RS2.5
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Hey Joel,

What im trying to figure out is why my fomula produces a straight linear line. See below top HP is @ 6250.

here is from a fomula
RPM HP Curve
2450.00 85.346
2900.00 106.532
3350.00 127.718
3800.00 148.904
4250.00 170.09
4700.00 191.276
5150.00 212.462
5600.00 233.648
6050.00 254.834
6250.00 264.25

But on my dyno runs, see below, top hp of 154 was at 5150 rpm, and then hp droped.

rpm hp - dyno
2450 72
2900 88
3350 108
3800 128
4250 140
4700 148
5150 154
5600 142
6050 140

Horse power doesn't seem to drop off until last bit of the rpm range, is that due to inefficency or maybe because I'm losing boost at that rpm range and thus Hp?

I might be asking the questions wrong too, so let me know if it what I'm asking makes sense.

thnks,
mm
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Old 07-20-2004, 04:43 PM   #5
cRayZee
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First of all, what's this formula you're using? How are you ending up with these numbers?
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Old 07-21-2004, 09:29 AM   #6
MadMax
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Join Date: Apr 2000
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Location: Danbury,CT <- Center of Univer
Vehicle:
2000 MY00 SRP RS2.5
"Stock" kinda

Default

one set of numbers are from my dyno run.

The others one are from a formula (cfm/1.5)-30 = hp.

I guess my question is: Is hp suppose to be linear in regards to the rpm range, or is there a curve in there due to inefficenticies, lower boost, etc.??

Thnks,
MM
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