Why does my power drop off once it hit 7k rpm? Dyno included
10-07-2009, 02:38 PM
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Why does my power drop off once it hit 7k rpm? Dyno included
My set up is pretty basic,
9.5 Wesico piston
Eagles rod
81mm stock sleeves
B18b1 block with B16a head(100% oem)
ITR cams
oem throttble body
victor x manifold
topmount manifold>3 inch downpipe>open Y pipe
Precision SC6152e
1000cc RC Injector
I dont get why it hit a brick wall at 7k rpm, is it because of my head/throttle body?
I've seen many different setup graph with stock head/TB and they are all smooth?
9.5 Wesico piston
Eagles rod
81mm stock sleeves
B18b1 block with B16a head(100% oem)
ITR cams
oem throttble body
victor x manifold
topmount manifold>3 inch downpipe>open Y pipe
Precision SC6152e
1000cc RC Injector
I dont get why it hit a brick wall at 7k rpm, is it because of my head/throttle body?
I've seen many different setup graph with stock head/TB and they are all smooth?
10-07-2009, 03:24 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
http://www.summitracing.com/parts/NGK-4554/ gapped at .016, the car is not breaking up.
10-07-2009, 03:38 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
Yeah, you need to upgrade the valvetrain. Stiffer springs and tit. retainers would help a lot. Head makes all the difference after 7k rpm.
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10-08-2009, 06:19 AM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
if you keep it up you're going to crack a retainer, so even if thats not THE problem it will be A problem
10-08-2009, 11:35 AM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
Looks like unsteady boost levels, tire spin, cam timing issues etc. there are multiple situations that can cause graphs like that
10-08-2009, 02:39 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
Definitely not unsteady boost level or tire spin, im going to be putting in some super tech valve spring and see what happen.
Last edited by StolenTeg; 10-08-2009 at 03:06 PM.
10-08-2009, 07:18 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
did you guys try adding 1-2* timing back in above 7k and see if it helps? what is the total timing up at redline out of curiosity
10-08-2009, 08:11 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
if you could, logging the afrs would help some. and yea whats timing up top? also are the cams degreed at all?
the graph is interesting to look at. those peaks at 6k and 7k look odd.
what wg and spring is on the setup?
the graph is interesting to look at. those peaks at 6k and 7k look odd.
what wg and spring is on the setup?
10-09-2009, 01:56 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
As far as data logging i dont have that but im pretty sure the a/f ratio were in the 11-11.5 in boost.
this was on stock cam gear, full-race top mount with 44mm tial gate with 14 psi spring. boost plot is solid so it not a fluctuation issue.
this was on stock cam gear, full-race top mount with 44mm tial gate with 14 psi spring. boost plot is solid so it not a fluctuation issue.
10-09-2009, 04:52 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
seems odd it would be the valvetrain since it does it at the lower boost level as well.........
i mean you don't see a stock motor's dyno do that at 7k rpm's
seems odd...
i mean you don't see a stock motor's dyno do that at 7k rpm's
seems odd...
10-09-2009, 05:02 PM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
Only other thing that could be a problem is my down pipe, i have a 5 bolt to v band adapter that is 2.25>3 inch but the turbo outlet port is 2.5 but that shouldn't make the graph look like that?
10-10-2009, 06:05 AM
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Re: Why does my power drop off once it hit 7k rpm? Dyno included
yeah. fix your exhaust.. that could be hurting it at that power level. is your intercooler big enough as well.. maybe the airflow isnt flowing well. could be alot of things.
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