Dyno fail

03spoolindmax

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Nov 9, 2011
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Had a local diesel dyno event today. I was first up on the rollers.

Just finished the truck up this past week. 4094/480 twin kit, hsp up pipes, lml manifold, lbz pump, stock injectors, SoCal stg 1 heads and a few other little things.

First pull on my street tune 373hp 697 tq

Decided to put it on my hot tune. Made 504hp 1008 tq

Could not get the 80 the light. Held 25k rail pressure. On the street I see between 10-15lbs from the 80 and around 45-50lbs total. On the dyno I couldn't even get 5lbs on the 80 with around 35 total.

It was on a dyno jet with a 5000lb drum. A little disappointing but oh well. I'll get it to the track in the next few weeks and see what it runs and go from there.

After that it's time for a beer or 30 :D
 

03spoolindmax

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Yeah. Everyone said they should of got a picture of my face when they told me I made 373hp.

Last year with my lb7 and a 366 I made 575hp. Singles seem to spool a lot better on that dyno. Even the operator said twins are hard to spool on their dyno.
 

LWATSON

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Correct me if I'm wrong but it takes longer to get a big single to begin spooling but once it begins it ramps up very fast. Twins begin earlier but ramp up slower? which would not do as well on a dyno?
 

03spoolindmax

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No gate at all.

On the street it lights and comes on pretty hard. Dyno just wasn't loaded enough to spool it.
 

03spoolindmax

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Correct me if I'm wrong but it takes longer to get a big single to begin spooling but once it begins it ramps up very fast. Twins begin earlier but ramp up slower? which would not do as well on a dyno?

That's almost what it did. Sounded like it was spooling at the beginning then fell on it's face once it got higher into the rpm range.
 

03spoolindmax

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Well I guess the dyno didn't lie. Ran the truck at the track today. Had a 1.8 60ft with 285/60r18 terra grapplers with a 13.02 1/4 mi at 103. Comp D calculator comes out to just shy of 500hp.

Rail holds steady at 26k. Egts were 1300* at end of track and I was seeing around 38 psi.

It's starting to look like a tuning issue. I'll be planning a trip to go see mark sometime in July and see what's going on.
 

03spoolindmax

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I may ditch my 4094 in the valley and put my stock turbo back on instead. It seems as if it's a tuning issue but also wondering if my 4094 is choking it out. Truck barely even smokes unless I'm spooling the chargers at the line. Even then it barely smokes at all.
 

LWATSON

future trans limpers
Jul 30, 2008
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Yes an 8.3 seems in line with your 1/4, Id definitely have the tune looked at. If you were under 8 in the 1/8 th Id look towards fuel issues.
 

CaptPhil

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How big of a tune is it? If you are holding rail that well have more pulse thrown at it and see what happens.