Hi guys. Can't find enough info to convince myself, so figured I'd ask.

I have a 98 JDM Integra TypeR. It obviously had a 4.7fd, until I recently upgraded to an MFactory 5.1. Works awesome, but I took it to the dyno post 5.1 installation and lost a few wkw. I was on 137wkw and dropped to 130, but a new set of plugs regained 3wkw.

Although my research indicates this to be the case, I need to confirm that the shorter ratio fd does indeed lead to a lower reading on the dyno.

FYI, on the day I did the 130, conditions were very similar to the day I did the initial 137. Subsequently, I dropped to 127. But that was an extremely hot day, so I'm basing everything on the 137 to 130 drop and a regain of 3 after changing the plugs.

Hopefully somebody has experience with this?

 

If no other changes were made then use that as your new baseline. Bear in mind the FD doesn't actually change the power output of the engine. For example if you had 197bhp before, you will still have 197bhp with an ratio FD.

 

I plan on using the current power as a new baseline, yes.

I understand the engine will make the same power, but will it show a loss on the dyno?

 

Depends on the type of dyno.

 

Yes, I agree.

Our dynos are the roller type where the cars are tuned under load, but the power runs
are on inertia.

I stand corrected, but I believe the rollers calculate the engine power in gear, then they
calculate the weight of the drivetrain when the rollers are still spinning and the car is in
neutral. The difference gives you a wkw reading.

Hyper Power dyno if I recall correctly.

 

I'm not familiar with that dyno so I can't comment on it.