IX low on power, excessive load, what's wrong?
 

A little history, this is my friend's IX and it's always been a beast. The last time I logged this car it made ~372/360 at 23psi. The owner grenaded the T-case and Tranny at the drag strip a few months ago and the car has been in pieces awaiting upgraded driveline components. While he was waiting on those parts he bought and installed a Nisei Race intercooler (I advised that he didnt need this until his turbo was upgraded). Anyhow, he finally got his TRE stg2 6 speed with shot peen and cryo treat and his stg 2 shep tcase back and installed but the car is seriously down on power. So he came by last night, I'm expecting him to break 400whp cause it's in the high 50's and he's got his downpipe open and we are planning to turn the boost up to 25 psi to reach our goals.

We go out log the car and find it's about 40+whp down on power and the load is crazy high. His boost gauge (Defi mechanical) is saying 21 psi but the load is ~300 so I'm thinking his gauge is bad and lower the boost down till we hit 2byte loads around 280.. but the car is then almost 100whp down. Tonight we are going to compression test and boost leak test but I wanted to know what you all thought. Here's a log and a DLL power / tq plot.

http://www.rgvimports.com/pics/MrEvo...3_00.38.44.csv

http://www.rgvimports.com/pics/MrEvo...aldnopower.jpg

Forgot to mention what mods he has

TBE (well actually, above run was with open DP)
BR Intake
Forge MBC
GSC S1 mivec cams
o2 housing
Walbro
Nisei LICP
Nisei Race FMIC
Exedy twin HD

i think the first issue is that your original logs might have been a bit high. 376whp on stock turbo with no race gas or meth at 23psi is far more then anything i have ever seen (i've seen people claim it before, but when i ride/datalog its no where close). race gas/meth would put you at that number. the datalog lab results i think are to easily skewed by simple factors such as wind resistance and wind speed/direction, grade of the road, alignment. all of these numbers can throw its calculations off by enormous amounts. say the day you got 376whp you were going with the wind on a flat road... if the wind was say 20mph thats a big help. now after the changes his alignment is not set right (assuming he dropped the subframe for the transfercase removal), and you do the run down the same stretch of road but this time the wind is 20mph coming at you. thats a delta wind speed of 40 mph. sense drag is an exponetial fucntion with windspeed, that 40 mph now is a huge difference (even 20mph difference is huge). in 3rd gear you should be approaching 85mph on the 5speed which windspeed and aero drag do effect it.

i've done enough DLL logs to take its power numbers with a grain of salt.

if you want to get good before/after numbers your best bet is doing it on the same dyno every time.

Sounds like a big boost leak. Most likely happened when he swapped out i/c's.
The turbo is working hard to try to make boost and as a direct result the MAF is "seeing" all the additional air the turbo is ingesting to try and reach the boost target. This is then translated as more load. Do a boost leak test and I would bet you will find one. Good luck.

^ what he said too. if you have a wideband on the car or can log the fuel trims, large boost leaks are easily identified at idle. lean idle and or trims way out of range are a direct result of boost leaks.

Interesting, and we did drop the subframe to do the t-case so the alignment may be a contributing factor. However, I've been able to repeat 360-370whp with this car many times.. I always log on the same stretch of road and I always do multiple runs going both North and South on my test road. There are variances here and there but I've not seen varances near as extreme as what you are describing in fact I rarely see anything more than +- 10whp without a reason. Not to mention I logged my own car right before his (same temp, same stretch of road, multiple runs) and was in the 350whp range (my car doesnt have his cams, o2 housing, walbro, or upgraded FMIC).

I wasnt sure a boost leak would make load go up so that is probably the most likely reason - Thanks for that info Drifto. Also I talked to Donald and he told me the IC flange was not round when he installed it and he thought there might be a leak at that connection. I shook my head.. why didnt you round it out before you installed it.. go figure. I'm betting we'll find a big boost leak.

load is essentially MAF/RPM, so if there is a big boost leak (it must be massive), then MAF goes way up without any more air getting into the engine. The car will run excessively rich and run less timing under those false high load conditions.

It was a boost leak right arond the inlet to the IC where he said it was bent. Fixed.

Someone change the MAF tables?