Ultraman wrote:
Doing some work for the courthouse should get you some points Tom, if ever you are caught drag racing your Corvette around town.....you never know....

cloudy here and looks like rain....working in office this week. It's down to a few more weeks of scouting left and it seems this year its been harder than most but that's just my age I'm thinking....I'm letting the help do more and me do less which is the way it must go...

I sat and thought last night of the Corvettes I've had and wrote down the engines. I don't know why? Anyway I've enjoyed these.....L75, L75, L79, LS5, L48, L83, L98, L98, LS1, LS3. No LT engines so that means I have to get a C7....to round out the list.....My favorites are the LS3 and LS1 and also the LS5 big block was fun.

Better get after it.....enjoy your day Guru's...

-=Jeff=- wrote:
Do you have a picture with the wheel off? Might help to find the right rotor

here is mine now:

BrianCunningham wrote:
Shows what paving can do

bam wrote:
Yea those splits are horrible!!! I am really happy with my BLM's now, there are a few lean spots in the data log I sent but I have already added a little fuel in those spots. I really think the timing is making the car buck. It must be pretty obvious that if timing is too advanced (don't know for sure if mine is or not) it would cause the motor to buck.
I sent you an email with my latest data log. Thanks for taking a look at it, I have spent hours looking at these things!

bam wrote:
Here are a couple of screen shots from data master, one from my car, the other was included with the program, you can see the differences in the timing.
http://s1113.photobucket.com/user/pho ... alog_zps5c03a47c.png.html
http://s1113.photobucket.com/user/pho ... ster_zps1e75370e.png.html

bam wrote:
On the initial hit of WOT I am running 11's on the wide band then it backs off to low 12's, should be ok there.

bam wrote:
Quote:

djxib wrote:


Great question. I did it initially so I could get a true read on the AFR at idle and part throttle cruise (i.e. without the ECM screwing with BLMs). However, when I started testing I realized that the driveability was so much better so I decided to keep it permanent.

Do you mean the BLM's were all over the place so you could not get a clear reading on actual A/F as a basis to start changing the VE table?
How did you set the prom to stay in OL move the temp up where CL kicks in so that the 02's would never come on?
Your wide band 02 is in only one side right? Or do you have two wide band 02's one in each bank of the exhaust, if not then how do you tune the "other" side? Or do you just figure it's not really a problem having one fueling for both banks?
How exactly do you tune your car in constant OL? Do you take the readings of your wide band combined with rpm, KPa data from data master and use that to adjust for lean/rich conditions? How do you know how much to adjust the VE numbers if your data comes from the WB 02?

bogus wrote:
That's one bad ass 240SX...

bam wrote:
Ok one last question; when you went open loop did you do it so you could get away from the sthometric A/F ration of 14.7 and run you car a little richer? Or was it something else too?

Matatk wrote:
Wow, that thing is a beast! What is the platform/details again?

bam wrote:
That's a healthy cam for a 350 (or is it a 383?). I would really like to have my wide band log with data master, could you give me more detail about the AC pressure switch, any place I could read up on how to do this, you wide band looks like mine - inovate?
I have split BLM's all through the rpm/KPa bands, so if I want to correct VE tables by dividing the BLM recorded with 128 then use that as a multiplier which BLM do I use since they are split, or do I simply take the average of the two and use that? Say one is 140 the other 120 do I use 130 then?
As for bucking, I call that steady cruise in lower rpm's (1000-1900 where you can't cruise w/o the car "bucking" like a mule. But even very slight acceleration of deceleration will immediately stop it. I have no hesitation when pulling away from a light either with WOT or part throttle. I think what you call cam surge is what I call bucking, it's exactly what I have below 1000 rpm which is really not a problem, the only time I drive that slow in first gear is pulling up the driveway.
My throttle stop screw allows the blades to be completely closed, I have heard you want all the idle air to come thru the IAC, right?

bam wrote:
You run in open loop so that means you never use your 02's right? Was the reason for doing this the supercharger? Or something else? Can you give me a brief idea of how this works? I am thinking that the split BLM's what ever the cause (unless it is vacuum leak, exhaust leak, which I am sure mine is not, I've checked this out really well several times) just makes no sense, there is no hot rodding reason (maybe for fuel mileage or emissions)to have one bank of the engine rich and the other lean all the time. I am thinking of running just one 02 and running it to both banks in the computer and then tune that side with my wide band. That will eliminate split BLM's, any thoughts? A guy with 6 years of working on this stuff, what you have learned is invaluable, thanks for the help.

bam wrote:
I really appreciate the comments, feedback here, otherwise one feels lost in the woods!!

I will try your suggestion on the PE, I was going to change it but for now I will leave it alone and do another data log first.

One question I have is; why the two 02 sensors? My 08 Grand Prix only has one located back of where the two manifolds join into one. The timing, map readings, temp readings are all the same for both banks of the engine,if so then why change the fueling. I can still see the split BLM's (although I have not logged since smoothing the VE tables, they may have improved but I doubt it) I am thinking this is because of the hot cam (112 lobe separation) and the LT1 intake short runners?? If I am right the problem is enhanced by having 2 02 sensors which are always trying to compensate for the reversion in the intake and constantly fighting against themselves. Andy any thoughts, have you been able to eliminate or improve on the split BLM issue with these motors?

bam wrote:
3-5" of snow here in the good ole midwest - yuck!! Here is what I have so far;
1)WOT still too rich. Adjusted the PE% Change to Fuel/Air Ratio vs. RPM table back off stock settings, result; WOT is a little less rich but now initial tip in at very low rpm's at part throttle is going very lean.
2)VEMaster is really messed up, I can now read the bin file it creates with C.A.T.S. but all the new numbers in the VE tables are really wacky, all over the place, really strange. I even tried it on another computer with no better results. I have a feeling this will never be figured out?! frustrating.
3)Initial tip in is worse as 1) above but I am thinking that I will go back into PE vs rpm and increase it below 1200 rpm and cut it back some more above that hopefully that help both, we will see.

One extra note, in C.A.T.S. I have adjusted the VE tables in the full graph mode. I could much more easily see peaks and troughs and smooth them out. The VE table is really smooth now and I can really tell it in cruise, the bucking is finally totally gone. nice!

I still could use some help here, any knowing comments appreciated.

Plus checked plugs yesterday engine is not running major lean or rich. All plugs a nice clean, tan color.

bam wrote:
Thanks.
I understand 1. PE vs RPM table, ok.
however 2) you lost me on this. Are you sure VE makes a new bin file because the version I have made a new text document that has to be opened with a word processor. The version of cats I have can't open it as far as I know. What are "peaks and troughs"? I presume they are related to rich and lean but how and what do they mean? Is high rich or lean? What I was trying to ask is; How does the new VE table created in the text document by VE Master get into the bin file, do you compare the two and manually make the changes? or am I missing something simple.

BrianCunningham wrote:
Quote:

djxib wrote:

Hi Brian,

Its a 236/242 0.6 lift (1.6RR) on a 115 LSA. Not a huge amount of overlap but enough to cause split BLMs and reversion problems. I'm currently running an open loop tune.

Are you running a 2 BAR MAP?

That's close to mine (with a lot more boost)
but it's a MAF car with the stock 1 BAR MAP
The MAF lets is know that there more air coming through.

No issue so far,

1Fast04Vert wrote:
Awesome, we really need to take it to the track sometime soon.

BrianCunningham wrote:
Nice smooth idle

Mind if I ask what cam you went with?

pianoguy wrote:
Quote:

djxib wrote:
Not sure I want to read that article either!

Found a couple hours to myself this morning - very unusual. Cruised in the 'vette and did some datalogging. Was just chilling at a stop light and some guy in a regular sedan pulls up alongside me and says "dude - that sounds remarkable".

Yes it does, yes it does.

Outstanding! I think it's time for a video ;-)

-=Jeff=- wrote:
Quote:

Looking good.. I did 35% on my vette last year

now all you need to do is lower it a little and give more of an evil stance

1Fast04Vert wrote:
Guess that means we will be getting chilly weather.

tjpreul wrote:
Its the xtreme energy 266HR-14, rated for 1-5k. I am not ready to go to the FMU. It is the one with the adjustment screw and will raise the fuel pressure while in boost.

tjpreul wrote:
I don't have datamaster. I have a wideband that I am watching, and pulling random plugs. It was showing lean, and when I pulled the plugs they were white. I adjusted the numbers up by .5 then it was showing rich. I moved them back down to where I had them and it was still rich. This is why I am going to try new O2's.

My cam is the Comp 266, which is basically a stock replacement. I will have the get the harness to do a scan. That is next on my list.

If this ends up not working. My back up plan is to install the FMU that came in the kit with the Procharger.

tjpreul wrote:
I bought the Procharger and unit off of ebay, it had the piggyback and software with it. This was a never installed unit that had been purchased in '06. However the Split Second p/n is FTC1-075. Which I don't think is available anymore due to the lack of sales. It is a fuel and spark management system. It has a vacuum hose that runs to the box, then sends the voltage to the factory ECU for the MAP reading. You set the output voltage by changing the value in the table to match the factory MAP at atmospheric pressure. By doing this it will compensate for having a forced induction engine. After that you have a table that you adjust the fuel levels with. According to them it is to trick the factory ECU to thinking it is at a different part of the set table. Then you are to readjust the fuel at that certain MAP point to even it out. Here is a link.

http://www.splitsec.com/technotes/Fue ... sing_2-bar_Map_Sensor.pdf

It is to add or remove fuel when and where it is needed. Then this table is an "overlay" of the factory table. My confusion is when I called Split Second they say to tune without the O2's. When I first start my car the AFR is reading high 13's to 14's. Then it drops to 10, which I think is when it goes to closed loop.

Yes, the signal wire from the MAP sensor is cut. The new signal is sent to the factory ECU from the piggyback. At 0 psi, I have them matched at 4.7v. When at idle (although not connected) the factory MAP has an output of 1.9v, and the piggyback has a 1.2v. This makes the factory ECU think it is running at a lower rpm, so then you can use the fuel table to adjust to the correct level.

djxib wrote:
(Some good write-ups / sticky on this topic in the tuning section of thirdgen.org).