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Acceptable amount of KR - how much is too much? by gtoformula
Started on: 10-25-2014 04:01 PM
Replies: 5 (242 views)
Last post by: nosrac on 10-26-2014 12:53 AM
gtoformula
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Report this Post10-25-2014 04:01 PM Click Here to See the Profile for gtoformulaClick Here to Email gtoformulaSend a Private Message to gtoformulaEdit/Delete MessageReply w/QuoteDirect Link to This Post
There are multitude of threads regarding KR, but I haven't found one yet that indicates how much is acceptable. Assuming that zero is ideal, what is an acceptable range? 2, 3, 4 ...?
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Dennis LaGrua
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Report this Post10-25-2014 06:33 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
.......................

[This message has been edited by Dennis LaGrua (edited 10-26-2014).]

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Dennis LaGrua
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Report this Post10-25-2014 06:39 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gtoformula:

There are multitude of threads regarding KR, but I haven't found one yet that indicates how much is acceptable. Assuming that zero is ideal, what is an acceptable range? 2, 3, 4 ...?


Ten different people will give you 10 different answers. IMO, more than a couple of degrees anywhere in the RPM range is cause for concern. The PCM will sense knock and cut the timing back and report the KR's but that's just a reaction to the problem. I prefer to tune or build to avoid the problem before it happens. I am running 11 psi of boost and no matter how we tuned some KR's were still there. After installing the intercooler my KR's are now zero. I advise all those that wish to run a 3.4" pulley on the series V superchargers that an IC is a must.
What does your setup look like?

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

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fieroguru
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Report this Post10-25-2014 07:59 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
Zero KR is ideal, but how much is OK really depends on when it happens (WOT, cruise, coasting, engine braking, transients, etc), how much it is (3 degrees or .3 degrees), and how long it happens (a single data sample or 20 data samples - this also depends on how quick you ecm is).
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gtoformula
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Report this Post10-25-2014 11:41 PM Click Here to See the Profile for gtoformulaClick Here to Email gtoformulaSend a Private Message to gtoformulaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:

What does your setup look like?

3800 SC series II with a five speed Getrag. Engine is currently stock. 2 1/2" mandrel bent exhaust with SpinTech muffler. About to install 1.9 ratio rockers. Also will be installing a 3.5" supercharger pulley ... currently running the stock 3.8".
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nosrac
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Report this Post10-26-2014 12:53 AM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by gtoformula:

3800 SC series II with a five speed Getrag. Engine is currently stock. 2 1/2" mandrel bent exhaust with SpinTech muffler. About to install 1.9 ratio rockers. Also will be installing a 3.5" supercharger pulley ... currently running the stock 3.8".


U need a 3" exhaust, a plog and 4% more fuel on injector #3, & #4.
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