legacycentral bbs

You can but for safety purposes you should still use an MBC.

douglas vincent wrote:Yes.... BUT!!!!!!!!!

The AFR may be off a point or two.... BUT IT STILL MATTERS!!!!!

C'mon... Just look at the graph. At 5500 rpm, power takes a crap, AND AFR dumps rich, and boost levels goes even worse....

It is all connected. I suspect a shitty turbo/wastegate/MBC combined with a MAXXED MAF signal.

I don't agree. The way it was explained to me is the cat can be thought of as an oxygen storage device. It holds and releases oxygen based on nothing but the catalyzed reaction with the exhaust which is unpredictable. It's a bit optimistic to think the readings are going to be a consistent point or two offset. I think it's a waste of time trying to draw conclusions from bad data.

The point is; Florin needs a new bung welded in right before the cat.

ericem wrote:i thought with rob tune you can use the stock bcs?

Yes, can use, but not optimal. For best control and response, I recommend going with an aftermarket boost controller.

-Rob

rob wrote:I don't agree. The way it was explained to me is the cat can be thought of as an oxygen storage device. It holds and releases oxygen based on nothing but the catalyzed reaction with the exhaust which is unpredictable. It's a bit optimistic to think the readings are going to be a consistent point or two offset. I think it's a waste of time trying to draw conclusions from bad data.

The point is; Florin needs a new bung welded in right before the cat.

I've been told by a couple different tuners that cat will affect the AFR numbers, but not by a lot. I still question that, but I haven't been able to prove that. When my car was tuned I was told that my wideband setup was matching their dyno wide band at lower rpm/load, but at higher rpm/load it was reading 1 AFR point lower, ie my WB read 10.5, while theirs read 11.5. What I don't know is, was that because of the cat, or was that because of my WB calibration.

Once I get the motor back together and running, I'd like to put in the test pipe and do some testing on the dyno to compare my wide band readings to theirs, and possibly stick the cat back in and see how the numbers vary.

rob wrote:

douglas vincent wrote:Yes.... BUT!!!!!!!!!

The AFR may be off a point or two.... BUT IT STILL MATTERS!!!!!

C'mon... Just look at the graph. At 5500 rpm, power takes a crap, AND AFR dumps rich, and boost levels goes even worse....

It is all connected. I suspect a shitty turbo/wastegate/MBC combined with a MAXXED MAF signal.

I don't agree. The way it was explained to me is the cat can be thought of as an oxygen storage device. It holds and releases oxygen based on nothing but the catalyzed reaction with the exhaust which is unpredictable. It's a bit optimistic to think the readings are going to be a consistent point or two offset. I think it's a waste of time trying to draw conclusions from bad data.

The point is; Florin needs a new bung welded in right before the cat.

There is a plugged bung right before the cat, haha. Nothing is there though, just a bolt.

Ah, ok. Next time you go in, we can ask Bob if he can put the dyno sensor in that port. Else, I can let you borrow my LC2.

-Rob

cool. thanks Rob. I put the car in the garage today. Got it up on jackstands and am ready to take it apart. So about adapting the ecu, do i get all the info i need from that thread or are you still working on some kind of conversion for my WS? I'm gonna be tearing into the car the next few weeks...

The tuners are pretty good at drift office too btw. I know a few of the guys there. I doubt the cat would really effect it all that much, i would say its more likely that having the probe at the end of that much exhaust has more of an effect.

Have you factored in the boost dropoff, and how these heads are only designed for midrange power? Overrunning your maf is likely, have you checked to see if you have a cracked knock sensor or a newer ect sensor? Looks like its the ecu trying to compensate.

tturnpaw wrote:The tuners are pretty good at drift office too btw. I know a few of the guys there. I doubt the cat would really effect it all that much, i would say its more likely that having the probe at the end of that much exhaust has more of an effect.

I am curious if you have data to back up your opinion?

Did you notice that up to the torque peak the AFR readings are flatlined lean? (16:1 +)? How would you explain that if the cat had nothing to do with it?

-Rob

Knock sensor is pretty new.

rob wrote:

tturnpaw wrote:The tuners are pretty good at drift office too btw. I know a few of the guys there. I doubt the cat would really effect it all that much, i would say its more likely that having the probe at the end of that much exhaust has more of an effect.

I am curious if you have data to back up your opinion?

Did you notice that up to the torque peak the AFR readings are flatlined lean? (16:1 +)? How would you explain that if the cat had nothing to do with it?

-Rob

Simple. Experience. You think hes the only vehicle to have strapped to that dyno with a cat? Not even close. Even a dyno shop just north of me has a pipe sniffer and has dynoed around 1000 or more vehicles. i will see if i can get my buddies dyno from that shop posted up here. He had a cat, it was a tailpipe probe, and was tuning to his wideband not the probe. And i didnt say it wouldnt. I said not all that much.

As for the lean, what makes you think that probe being used so many times is even all that accurate? Difference being length of pipe, heat, muffler, and cat can all play factors but its not just the cat. As i said above its more likely the ecu is controlling a lot of that.

I wouldnt doubt the bpv is leaking under high boost either. My stock one did, the wrx one i have does, my friends 06 wrx did until he went fmic, and my friends moms 02 does.

tturnpaw wrote:
Simple. Experience. You think hes the only vehicle to have strapped to that dyno with a cat? Not even close. Even a dyno shop just north of me has a pipe sniffer and has dynoed around 1000 or more vehicles. i will see if i can get my buddies dyno from that shop posted up here. He had a cat, it was a tailpipe probe, and was tuning to his wideband not the probe. And i didnt say it wouldnt. I said not all that much.

Generally speaking, doing something incorrectly 1000 times still does not make it right.

In my mind it's pretty simple; the cat's job is to absorb and to release free oxygen depending on the chemistry at that one moment in time. It means there are transient and absolute errors introduced. How much and how often is unpredictable. I'm not saying it isn't done, just for me personally I try not to draw conclusions from flawed data. You can ask Innovate, they will tell you the same thing. A good tuner won't rely on AFR targets anyway, but this is a side point...

As for the lean, what makes you think that probe being used so many times is even all that accurate? Difference being length of pipe, heat, muffler, and cat can all play factors but its not just the cat. As i said above its more likely the ecu is controlling a lot of that.

Right, unless you know the guys and their equipment, you can not be sure that their sensor is in good shape and calibrated. I also agree with you as well that readings from the tail pipe are not that great either. I personally use my own WB so I can eliminate these variables. But my point was that you see the AFR completely maxed out lean. We both can agree that this reading is 100% bogus. The engine was most certainty not running with an AFR of 17:1+. It can not be explained away by an out of calibration sensor.

So like I said, I wouldn't read too much into what the AFR chart shows. If you (or anybody) else disagrees with my reasoning and finds value in it, I'm not going to hold it against you....(too much)

-Rob

dscoobydoo wrote:The answer is: you are still running the EJ22T heads.
My dyno plot looks similar in that the power drops off at 5500 rpms.

Word.

My stock dyno from 2 years ago, has a similar torque drop around 5300 rpm (yes, hard to see numbers on the plot).

Some time this summer, I hopefully will be able to get a dyno run in to get some numbers on my current setup... both with Revtronix Stage 2 normal and power modes. Although, not like it really matters anymore since revtronix is EOL.

Here's some additional catalytic converter info. Pretty much all modern catalytic converters are reduction-oxidation catalysts. If you look at the chemistry involved the oxygen released from the reduction staged is then used in the oxidation stage. It most likely is not going to be a one-to-one ratio, i.e. the amount of oxygen released is not the same as the oxygen used. But depending on cat efficiency, engine load, AFR, etc, it's going to be close most likely within 1 AFR point.

Here's a link with the chemical equations.

http://auto.howstuffworks.com/catalytic-converter2.htm

BSOD2600 wrote:

dscoobydoo wrote:The answer is: you are still running the EJ22T heads.
My dyno plot looks similar in that the power drops off at 5500 rpms.

Word.

My stock dyno from 2 years ago, has a similar torque drop around 5300 rpm (yes, hard to see numbers on the plot).

Some time this summer, I hopefully will be able to get a dyno run in to get some numbers on my current setup... both with Revtronix Stage 2 normal and power modes. Although, not like it really matters anymore since revtronix is EOL.

I wish I could find my plot from two years ago. Maybe it was the Delta regrinds, but power did not drop off so nasty when it was only making 200 whp at wastegate pressure.


Again, without detailed logs and tuning data, dyno plots with funny curves only lead to speculation.

The drop off up top is not entirely due to the ej22t heads. the exhaust, turbo, IC, etc...play a large roll.

Just for comparison:
Florin1's dyno shows a 30hp drop starting at 5500rpm.
My '93 with larger vf12, efficient AWIC, etc.. dropped 15hp but it didn't start the decline until 6000rpm.
Then I added P&P&coated stock manifold wth high flow cross, and Delta 220 cams and my top end holds to less than 5hp drop at redline and it only drops in the very last tail of the curve.

Yes, there are better flowing heads out there (which could probably give me 15+hp more than the ej22t heads a redline) but the stoke heads alone are not causing large "Drops".


Thanks for making the effort to help develop a chip for us. I look forward to seeing results on how the chip can handle new system components and make good/safe power.

Your baseline looks good!

Thanks buddy. . I figured cold hard numbers would help everyone...

You can- or should be able to.