Help with power hitting a brick wall???
09-23-2015, 06:57 PM
#1
Staging Lane
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Help with power hitting a brick wall??? Hi I am after a bit of advice on where to go from here, my power on the dyno hits a brick wall at about 3000 rpm and flat lines from there. Its not a wavey curve, just up to 600rwhp then flat for the rest. A/F ratio stays nice and fat at 11.6-11.8, no signs of knock. Just something bottle necking.
Combo is 408 forged, 9.5 comp, mid 230s cam, beehive springs, single gt5588 turbo, turbo 400 trans, 3000 stall, 9" diff with 3.25 ratio, 27" street tyre. Has a 5" dump pipe to twin 3.5" under the cart to the diff then twin 3" out the back.
Wondering if anyone has experienced this sort of thing?
Its not the turbo as it done a similar thing with the last turbo, revs don't flare like a tranny/converter issue might do, Its got plenty of airflow in and out, makes boost quickly and goes hard. This combo should have alot more grunt
Valve train?
Thanks in advance.
Combo is 408 forged, 9.5 comp, mid 230s cam, beehive springs, single gt5588 turbo, turbo 400 trans, 3000 stall, 9" diff with 3.25 ratio, 27" street tyre. Has a 5" dump pipe to twin 3.5" under the cart to the diff then twin 3" out the back.
Wondering if anyone has experienced this sort of thing?
Its not the turbo as it done a similar thing with the last turbo, revs don't flare like a tranny/converter issue might do, Its got plenty of airflow in and out, makes boost quickly and goes hard. This combo should have alot more grunt
Valve train?
Thanks in advance.
09-23-2015, 08:05 PM
#3
Staging Lane
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You are a legend, the flexi is something I had forgotten about checking. Looks like a bottle neck to me. Its about 1" in diameter at the inner end. Hopefully thats my only problem. That is in my 2.5" crossover.
09-24-2015, 08:17 PM
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Staging Lane
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I agree I used the wrong type on flexi but I believe I needed something to allow for a bit of expansion. Its been addressed now so just need to slot in another run on the dyno. The way it looked it should be a decent jump in power.
09-27-2015, 12:04 AM
#7
Teching In
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Yes you want a flex joint but not that type. Search interlocking flex joints. You got lucky actually. I learned the hard way not to use those pre-turbo when the guts of the flex joint let loose and decimated the turbine wheel on my chevette.