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Why is a Dynapack dyno result allowed for awd but not 2wd?

Don't Dynapacks read really high?

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#315 TTB Nissan 350Z

Not exactly. They can be properly setup and adjusted.

When I had my car tuned on the Locash Dynapack, I made about 136whp/124wtq consistantly (in the summer of 2008). When I had the car dyno'd for TT/PT the following summer, I made about 135-136whp/122-123wtq on the two different Dynojets (AZDynoChip and Xtreme Dyno). When I had the car dyno'd for a TA competition later in the year, I made about 139whp on a different Dynapack (UMS Tuning). HOWEVER, this was in the dead of winter and at night AND with a fan blowing near the intake.

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As seen in Super Street FF Battle 4! (November 2012 issue)

They get special dynos, if they have to dyno at all!
Remember AWD guys don't have to play by the same rules everyone else does.

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Corvette Track Medic
#222 - 09 & 12 TTS Nat Champ
#153 -10 & 11 TTA Nat Champ

I'm asking more for my own benefit - shop doing some work on the car has a Dynapack. Dynojets are far away.

Aren't you just making sure that your mostly stock Corvette isn't over the TTB 10.25 adjusted limit, right? I think a Dynapack would be fine. You need to take advantage of that maximum power limit.

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Randy Johnson (Midwest, Great Lakes)
#767 2005 Subaru STI PTB

I am not competing in TTB this year.

Give 'em hell.

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Randy Johnson (Midwest, Great Lakes)
#767 2005 Subaru STI PTB

Randy - you're not alone....my adjusted ratio for TTB this yr is 11.8, which is very similar to Dominic's. Mine was 12.1 at the 2011 Championships. I need to find some more HP....damn NA 4cyl.

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1993 Nissan 240sx
TTB #940 Great Lakes region

From my experience the lower power Dynapacks (4000 series) read on the high side for AWD cars. The bigger packs were more in line with a Dynajet but they have changed their model names. Unlike a Dynajet roller the Dynapack takes the power measurement without the wheels so it should be higher. Now because the dyno is a load based dyno you can change the ramp rate, hold time, and a number of things to make the HP go up or down.

In the end I've tuned on just about every dyno out there and they all read differently even from shop to shop with the same exact dyno. If I was running nationals and they had a Dynajet I would make sure I tested on a Dynajet. From my experience, on the same day, I jumped from a Dynapack 4000 (12 second ramp time) to a Dynajet and at about 315 HP the Dynajet read 25 HP less. I'm sure if you tweaked the ramp time on the Dynapack you could get the number to be closer as a longer ramp time will heat up the engine and intercooler (turbo car) lowering the HP.

Phil Grabow

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Element Tuning STI Hydra EMS, BC Racing Suspension, Fulcrum Aeroworks,Swift, Clutch Masters