ClubLexus - Lexus Forum Discussion - 1999 SC400 vvti Dyno

Since this car will be testing the PPE headers soon there is some conversation on the GS4xx forum about it.

Quote:

Originally Posted by bcsc400 (Post 6115295)

The dyno used was a Dyno Dynamics.
Known as the heartbreaker dyno because it typically reads 17% lower then
a Dyno Jet. The Dyno Dynamics used was recently calibrated and is using the latest software. This new software calculates Dyno Jet ratings because most tests are done on the more readily available Dyno Jet. For legal reasons they can't put rated Dyno Jet power, they call it flywheel. The 255.8 hp and 290lbs torque is at the rear wheels. The compression on my motor is bang on spec and
runs strong. The car has 62,000 miles on it. Here is a link to the shop that did my car. It shows some of the other cars that have been dynoed and with talking to the other cars owners the numbers appear to be accurate.
http://5252motorsports.com/

That said I am suspicious that these numbers should be considered equal in testing to Dynojet readings. I am somewhat surprised that power peaked WELL below where is should have. Dyno showing peak power at roughly 5350rpm where it should be around 6000rpm. The 430 engine peaks around 5600rpm so this is even more evidence of something out of the ordinary. Torque peaked at 3500rpm and should have been more like 4000rpm. Also unusual to see a car dyno from only 3200rpm... good... but unusual as they downshift when going to full throttle.

In addition to the headers bcsc is planning some additional changes to his already nice exhaust system. My guess is the headers will not help and may hurt power and torque below 3500rpm but that may not show up in this graph. The exhaust mods may make up for this loss. Two steps forward, one step back?

As long as the above data was repeatable it will serve fairly to compare whatever gains are seen with mods such as headers.