update:

technosquare did a flow bench test of the RT cats... they are flowing nearly the same rate as my test pipes that were custom made from mandrel bent pipes... clearly they are very high flow... and very much an improvement over the stock cats.... i am still requesting CFM flow rates for comparisons..

as far as the lean condition, they're still investigating.. i didnt want this to be a warning thread.. just a curiosity thread.. hope i didnt scare or spook anyone. that was not my intentions..

more updates on the flow rates soon. thanks

--cheston

 

No the cel light is just there for christmas, the o2 sensor has no important use either. Just keep NOT driving it around.

 

There is a secondary O2 sensor which serves as a backup- However you should have the primary O2 sensor replaced ASAP since you're now running w/o a back up.

 

[This info has been put on other threads quite some time ago, but here we go for the cause:

The first mod was the ATI procharger. Put it on, got it dyno tuned. It looked a little lean in the higher rpms, tried to set the slides to maintain about 11.5 a/f ratio across the band. Ran very nicely to redline and no issues.

The next mod was Borla headers and Catback, keeping the stock cats. Same day took it down and had it dyno tuned just to be conservative. Lo and behold, it was running leaner. Tickled the fmu slides and got the band down around 11.5 a/f again. Ran very nice and no issues.

The next mod was the RT cats. Could not get it tuned for about 6 days because the tuner was on a trip. Kept the car under 4000rpm for six days (do you appreciate how HARD that is to do?!!) Good thing, because it definitely was lean, and had to richen it up again. to keep it down to 11.5 at 5500 and 11.8 at 6000 rpm. That was trending a direction I did not like, and too quickly, so plotted out the a/f on the dyno, and immediately drove over to TS and had them custom reprogram the ecu to the dyno map, and also retard the timing at the top end about two degrees for some extra margin of safety. Definitely hurts the gas mileage, by the way.

Took the car up to 7100 rpm, no problem, no ping (and definitely no kaboom).

run the car now for 3000miles on this set up, no problems and lots of smiles.

Have not taken the car back for yet ANOTHER dyno, but probably will in the near future. It is pulling even more strongly than before the ECU reprogram, so I think there are some hp and torque gains from it, in addition to the increased peace of mind on running lean at high rpms. But I do not have dyno figures for it yet to compare pre and post flash of the ECU.

FYI, the preflash rwhp was 346.6 and the torque was 306, both third gear. (please no flames on third gear versus fifth. The purpose was tuning, not chest thump numbers). And by the way, when you sit in that little puppy at WOT with 340+hp in third (and we did a couple in fourth) gears, facing a concrete wall and held on the roller with chains and web belts.....and you extrapolate the equivalent speeds to a fifth gear at the same rpms......I was ok with third. I will see what it does on the track at WOT in fifth...and SIXTH....in a couple of weeks.

Hope this helps with the process.

 

 

So what was the verdict?

Im guessing only people with prior TS ECU flashes were running lean after installing the RT Cats?

 

So what was the verdict?

Im guessing only people with prior TS ECU flashes were running lean after installing the RT Cats?

 

here is my before and after a/f mixtures when I added Kinetix hi-flow cats.

I have injen/pop hybrid intake, borla td, grounding kit and now the hi-flow cats.

seems my air / fuel is the same in all six runs (taking away the 2 really strange readings). Much higher LOWER in the rpm range.

 

here are the four runs with the kinetix hi-flow cats.

 

after the new plastic plenum goes in I plan on going up to TS for an ecu flash.

Is this a problem that Tadashi (sorry if spelled incorrectly) can fix?

and will the flash help these mods "achieve more"?

 

I have the same a/f curve as you all bark and I have the TS ECU flash. Our cars are running very lean up to about 5500 then a little rich to red line. Danny and Tadashi have been working on a solution. Crawford has been helping as well. They are trying to keep it 12.5 to 13 through out the rpm range. Mine is going back hopefully next week to get it fixed.

 

so they currently do not have a fix but are working on it?

 

that's correct

 

cinergi1--What mods do you have that are contributing to the lean condition?

 

As far as I know the lean problem is being caused by the RT cats. It seems that the ECU takes a O2 reading just before and just after the cats. The RT cats because of their much higher flow are causing the reading taken after them to be much different than the reading before the cats and it seems to be confusing the ECU, at least that is the current theory.

My other mods are crawford plenum and borla TD.

 

I have seen many dyno's with the same curve as all bark's. Some have had stock ecu's and some have had TS ECU's but the one common element among all the dyno's that exhibit this lean to slightly rich curve is the RT cats.

 

Then...cruising down the highway at the lower RPM's could be hard on the engine--running that lean condition for an extended period of time?

 

I doubt it - If I am not mistaken those curves are all generated at WOT, so the engine is open loop on air/fuel ratio control (i.e. the two oxygen sensors are not taken into consideration).

In all other instances (partial throttle) the ECU is in closed loop mode and is trying to maintain nearly a stochiometric ratio so that the 3 way catalytic converters can most effectively clean the exhaust gas.

Cheers!

 

So why would this not be true of test pipes? One of my Nissan engineers was here today and he said he doesn't see how it's possible for the cat's to run lean and not the test pipes, but then he also said he has no personal knowledge of high flow cats or test pipes.

 

That sounds logical to me. The assumption is that the ECU is indeed richening up the mixture at partial throttle.

My experiences on running lean, blowing up engines, etc., is on high performance 2 stroke engines--mainly snowmobiles. We always ran EGT (exhaust gas temperature) guages with probes located maybe an inch from the exhaust port of the cylinder. Lots of times you'd see very high temp readings at partial throttle and medium RPM's--it all depends on how the carb was jetted for the mid range throttle application, or how the fuel injection was calibrated (if it had fuel injection). I have seen 2 stroke engines burn down when running partial throttle and very little load on the engine, though this was rare and usually on engines that had a performance porting job.

Well, our super advanced ECU's hopefully compensate properly for all of this!