Here is the url-

http://mixxdigital.com/john/logs/

I'm new to this stuff, do I decided I'd throw the logs out there and have the experts take a look

John

 

Only thing I could tell you would be to pull just a hair of timing and see if you can get rid of that knock retard. It's not hurting anything, but might as well get rid of it.

 

You have a large split between banks - check for air leaks.

You are running way to rich - lean it out to around 880-890 mv at WOT.

You're running at 90% DC on your injectors. Your engine is flowing a decent amount of air and I'm guessing your making around 350 at the rear wheels. Think about upgrading to 30lb injectors to get your DC down.

 

Question- Looking at the logs, does it look like I could benefit from a 52mm throttle body? I assume I would have to get bigger injectors at that point, that is if I could benefit from it.

Also, no exhaust leaks, what else could cause the split??

John

 

If you had a large intake restriction, you would start to pull a vacuum at high rpms - which you are not. Your MAP readings looks good so I don't think you gain much if any HP going to a larger TB.

I have a hot cam and ported heads also. I pulled 362 rwhp at 5900 rpm with a M6. It would have been more, but I had valve float. You are pulling about the same amount of air that I am according to your MAF sensor. My car is tuned pretty well and I needed larger injectors above 6000 rpm to be safe. Injectors do funny things when pushed much above 85% DC.

If you are sure you don't have any exhaust leaks, check your plugs, wires, and injectors. I have a BLM split at idle but at WOT, the BLMs should some together. This would have to be a misfire, clogged injector, or a large air leak.

 

Rich- Where are you seeing a large split in blm?
I hope you weren't talking about a split in O2 voltage?
I hope people are reading some of the posts that take place in here and are learning that O2 voltage is not the way to tune. There have been a couple posts in the last couple of weeks regarding this.

FastZ- the 30's might be a good idea, but I don't think they're necessary right now. Don't trust the DC calculations as many believe that they aren't quite accurate. Rich is dead on about the TB too. Doesn't look like you have a restriction based on map. Probably wouldn't be worth the $$$.

 

My bad - I did mean the split in O2s and not BLMs. During WOT, it looks like his BLMs are lock to 128 (as are mine). Yes, the narrow band lamba O2s are not very accurate outside stoic, but they are not THAT bad either. I have tuned several cars by O2s and then verified them with a wideband O2 on a dyno and have not been more than .5 from my 12.8-13.2 range. When I see O2s above 980mv, it's RICH!

When I tune a car, I get the BLMs in line first, and then tune WOT by the O2s from 890 at torque peak to around 870 at peak RPM. Then I can finish it with 1 or 2 pulls on a dyno with a wideband. No sense in wasting money on the dyno till you get it close.

I've seen a lot of people show dyno pulls of 400 rwhp with stock injectors as proof the stock injectors are fine - but I'll bet you $100 that those guys will make more HP with a larger set of injectors if they are seeing injector DC over 85%. GM didn't put larger injectors in the LT4 for nothing - and they make a lot less power.

This is what I have seen and of course, your miles may vary.

 

You had me confused there for a second with the 2 usernames Rich!
Sounds like you've found a way to make O2's work for you. I just don't like suggesting to others that they tune by O2 voltage. Here's a pretty good reason why...I actually have been out playing with the pe vs. rpm in my car for the last hour or so.
I've had a little bet of retard right at 4500rpm. Started out by pulling a degree of timing here and there. Didn't help, so I started adding fuel...and the more fuel I added the more my O2's came down and the more the knock went away! They are right around 870-890 now and I still think the car is a bit lean.
I'm only trying to get 34* of timing in it and it still wants to pull out just a little right at 4500rpm. Guess I'll do a little more screwing around tomorrow and keep adding fuel to see if the knock goes away.

Also: I can send you the datamaster logs I just made that show my injectors at 80 something percent duty cycle. That's pretty impressive for a car with a cold air and cat-back!

 

Sorry about that, I logged on at home and was logged on with an old logon that I had forgot about. I'd like to see your datalogs. What I have seen is that you can err in making your car too rich by using your O2s, but not the other way around. An air leak will make your car read lean, and if you tune by them, you will make your car too rich. I cannot think of anything that will make your O2s read rich when your car is actually lean.

If you added fuel and your O2s read lower mv, the may following may explain it:

You've added so much fuel that your fowling your plugs and or O2s.

Your exhaust will expand when hot and could create or fix an exhaust leak. Was the engine under the same operating conditions when you logged data?

Your fuel pressure could be dropping so lenthening injector on times doesn't really help. My stock fuel pump did this when it got old and now I'm running a 255 lph walbro.

 

OK. I'll ge them off of the other laptop tomorrow.

Maybe, but after seeing the voltage output of an O2 I don't see how anyone can trust them in such a narrow mv range to give them any idea of a/f ratio.

Confident that's not the problem

Yep. I was out driving the car and after logging data I would review the log and make changes to the bin file and reload it on the side of the road and continue on to make another datalog.

That would explain why adding pe fueling would make no change in O2, but not sure how that would make O2 drop.

 

heard you leave special the other night in murfreesboro car sounds really good mine will be out shortly with a pretty much stock carb 350 out of a older z28 cause i am going carb on my lt1 engine when it is finished

 

Thanks a lot I'm always afraid to stay in the throttle for too long because of cops, but I kinda had to do a little blip

How's your car coming? Do you have all the parts ready?

John