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Re: Dyno... 4 motors, 3 days.
[Re: Leigh]
#920536
02/06/11 10:34 PM
02/06/11 10:34 PM
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Joined: Jan 2003
Posts: 8,547
State College, PA
RyanJ
OP
moparts member
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OP
moparts member
Joined: Jan 2003
Posts: 8,547
State College, PA
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Quote:
Finally looked at this. So, you saw visible reversion evidence in the intake of the freshend engine? I ask this, as usually, an A, B, A, comparison, is the benchmark of diagnostics. Not trying to be an A S S. I have an invested interest, as my intake manifold and exhaust side shows heavy reversion.
Thanks,
Leigh
I'm still lost on your question.... but I'll try to answer it as simply as I can....
The motor was ran in guys car... was slow...sent me the motor.
I tore it apart & one of only things I found that may have caused the power to be off was alot of reversion in intake runners/ports.
Made some small minor changes to motor including retarding the cam from where it was installed, which should help reduce reversion, it was installed too far advanced...
So put it on dyno with his headers.... did not make good power & motor was dying above 6100 RPM. My feeling was the issue @ high RPM was not valvetrain related or sonic choke in the heads. So I leaned toward the headers.... We changed the headers & bang, power is way up & motor now pulls good to 7200 RPM. Power is where I would expect it to be....
So no, after that I did not take the intake back off or heads back apart to look @ reversion, & to be honest with only 7 or so dyno pulls on it I'm not sure it had enough pulls to even really start showing much carbon/exhaust soot back in the intake runners if I wanted to see anything. After a motor runs 15-20 dyno pulls & you pulls heads off, there is hardly any carbon tracing left on the pistons, let alone enough reversion tracing to tell you anything.
If you are seeing exhaust reversion into your intake runners, you have a problem somewhere, excessive overlap on cam, poor header design, excessive back pressure in exhaust system etc. The valve job & seat/valve heights can play a role as well.
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Re: Dyno... 4 motors, 3 days.
[Re: mopar dave]
#920539
02/07/11 12:24 PM
02/07/11 12:24 PM
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Joined: Oct 2003
Posts: 11,704
W. Kentucky
justinp61
I Live Here
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I Live Here
Joined: Oct 2003
Posts: 11,704
W. Kentucky
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Quote:
i'v beem using the TTI 1 7/8 w2 headers on my 600hp 408/indy heads. would the hedman 1 7/8-2" headers be over kill with my application?
I looked at the 1 7/8"-2" for my 408 but went with straight 1 7/8". Mine makes around 550 hp.
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Given the expected power of that engine I would say that 2" primaries may not have been the ideal size. It would be interesting (for me anyway) to see the same headers with primary extensions on the pass side and merged collectors.