Kaboom, I heard it here in Cali.

Greg

 

Sorry guys had to work late tonight which sucked almost as much as the dyno session last night so here it goes. Like I said yesterday I was short on time as this was a spur of the moment thing so I got there early to let the car cool down but set up took forever and yes this was his first Z06. Don't want bore you guys but in short the first pull came around 8pm because the dyno kept applying brakes at 2500 rpm and he thought it was the car because of the service parking brake lamp and stability lamp that stayed on the dash. Come to finally find out it was the computer loosing it connection with the remote that he had with him in the car so it was the dyno no the car. Not knowing I was going to dyno the car I had put on a new set of A/M wheels and a new set of Michelins last weekend and traction was an issue on the first pull and we are in hour 4 by then. Second pull got better results but the gremlins came back and the dyno was done and so was I, so I ask him to take it down because I was concerned with the warning lamps. As I said at the beginning the purpose of this was to check afr's not do a tune and when he showed 11's I was sceptical to say the least even though my freshly cleaned tailpipes were pretty well soothed up but the car was idled a lot during the gremlins. Like I said I'm no dyno wizard and never felt comfortable from the get go but I'm giving y'all all I got and I actually felt bad because this guy was having a bad day and really was trying. Sorry for the let down but I'm doing some research on well known company down the road. You guys gave me some great info that will help me the next round so thanks a ton for that but maybe I should go back to pulling a spark plug and checking the color.

 

Its ok. Keep trying until you get it right. And share at that time if you like.

There is no time limit on getting it right and posting accurate data that may benefit us all. It will be appreciated regardless.

 

I would agree the reading they got of 11:1 AFR sounds too rich for your combo, but just because they guy has a dyno (as you found) it doesn't mean they know what they're doing. Check around for a more experienced guy and give it another try.

I will say that the peak RWHP # of 591 seems right. That's exactly what my car (16 Z A8) dyne'd at with the Halltech CAI, and torco.
The X-pipes don't make a huge difference in power typically, I have seen dyno gains of 5-10 RWHP with the Borla. Also the PTB gains are supposedly mainly at lower RPM's, so they may not show (or show much) on the peak power.
Thanks for sharing!!

 

guy on the air filter only thread got 18whp when he added the Borla X pipe.

 

I have stock tune and my A8 Z AFR goes to 10.2 when WOT...believe this is the COT kicking in....pig rich.

(Mods – CAI Halltech/TRIC, ported TB/snout/blower, main cat delete pipes, Corsa X, 170 F thermostat, inter cooler 1,7 gal extra tank, 2.30” upper pulley, Aeroforce Tech gauge with O2 wideband)

 

This is a good point.
On a stock tune, your COT will begin kicking in around 5250 RPM...gradually the AFR will richen from around 5250 rpm to a maximum richened point around 6250 RPM (based on my previous dyno's on my car).

My car totally stock had a "tailpipe AFR reading" at 11.5-11.7:1 up to 5250 RPM, and then it richened up to 10.2:1 due to COT.

My car after the CAI and Torco (only mods) had a "tailpipe AFR reading" at 12.4-12.5:1 up to 5250 RPM, then richened up to a AFR of 11.0:1 due to COT.

Keep in mind, the "tailpipe AFR reading" can read 0.2-0.5 AFR points leaner than the pre-catalytic converter AFR reading, depending upon who you speak to.

 

stock tune?!?!?

 

I have stock tune and my A8 Z AFR goes to 10.2 when WOT...believe this is the COT kicking in....pig rich.

Yes, stock tune......pre-catalytic AFR readings.....

 

Wow all those mods on a stock tune. That is pretty brazen. You say 10.2 AFR, that is even crazier I think with those mods and a stock tune.

 

Back to the tail pipe wide band O2, lots of shops still use them today, even BIG named shops that tune lots of cars every week, so one would "hope" that there has been verification of only minor AFR discrepancies...

I recall back in 05, I insisted on a local big name shop use a wideband O2 sensor in the Y pipe as opposed to the tail pipe adapter....Initially the tuner did use the tail pipe adapter to tune with it. Afterwards, I convinced him to patronize me and move the exact same sensor from the tail pipe adapter to a bung in the Y pipe just after the header collector (F Body)...

We made some pulls at the exact same operating temp, about 30 mins apart, and the car was .3-.4 richer using the bung in the y pipe vs the tail pipe. Not a lot of difference but there was some. This was with no catalytic converters. No way would I trust a tail pipe wideband with catalytic converters, way too much room for error.

One benefit to the tail pipe wideband reading (if you can call it a benefit) is the car is actually richer then what it is tuned at...adding another level of safety)..

For me, I'm a data/numbers guy, I want the stuff accurate, and I want to know exactly what it is.

On my C5Z, I actually had 3 wide bands on it....(a dual channel Innovate, one on each side, and an additional AEM). And with all of this, they all still read .2-.3 different.