Engine and car in sig.....The car is slow from a stop if you punch it. There is no bog or hesitation just no ***** off the line. It will not break the tires loose at all. Draged a buddy and his mostly stock LS1 destroyed my car off the line. I have a 700R4 with a 3000 stall ACT 9in converter. Would bringing in the timing faster help with this?

 

Could be AE issues. Enough to get going but not enough to give it that pumch off the line.

Experiment with timing under the converter.

Some cars like no timing until the converter some cars like timing until the converter hits. Puch out both ways and experiment.

Some cars are lazy if u have too much timing or too little timing when the converter hits.

Try dropping the timing out in the 400-1200 rpm area u will never use like 90-100 kpa. Sometimes that with leaving the fuel helps work out as adding some AE into the VE table.

Just make sure your not having tip in knock or the like, and tread carefully if u do. I a currently working on a somewhat simliar issue with my 383 on getting a nice transistion from cruise/stop to WOT.

So far messing with the AE and lowering the higher rpm PE TPS enables have helped alot but there is still some left

I remember digging up alot of AE type stuff for StealthRams, make sure u search for everything mentioned or that u can think of.

U got a wideband on that thing?

later
Jeremy

 

I am using the LT4 timing table now.....its seems that it fits my combo real well.....just a few knock counts under hard accell none while cruising. Without a WBO2 I am sort of guessing at the AE stuff. I am using TRAXION's AE TPS and MAP tables with about 5% less as a starting point. Not sure if its close or not. The cam I am running is a 224/230 .580/.590lift 112lsa.

 

Hmmm yeah AE is a pain with a wideband let alone without one.

U could also try dropping you TPS PE enables lower temporarily and see if that helps.

Also try dropping out timing in the main table a little faster.

later
Jeremy

 

Have you put a scanner on it? Are you getting any knock that it could be pulling timing out?

 

Yea, I have scanned it 100's of times and have the timing pretty well set with only a few counts under hard accell. What I dont have is a WBO2 to get the AE and PE 100%. Right now I am kinda guessing........

 

You'll probably save some money by buying an LM1 or the likes. You've already obviously spent a lot on parts, now you have to make them work, so just do it right. With those parts, you should be able to put a hurt on many other cars.

 

To get the engine up against the convertor from a stand-still punch, I would add timing. Until the convertor starts to hook up there is very little load on the engine. Try adding timing, even up to 8-10-12 degrees at 90-100 KPa from low RPM up until the convertor starts to hook.

At that point the timing will probably need to be reduced to prevent excess loading on the engine.

A lot of the smaller engine'd GM cars are set up with a launch mode. They do exactly this except there are qualifiers and such. Such as a max MPH and minimum TPS% in order for this timing to be added. Gives them good punch off the line.

RBob.

 

RBob would I be able to use the PE Spark adder in the 8D mask to accomplish this? Possibly add 12 degrees and then taper it off to zero at around 2500rpm?

 

That may work. The PE SA table is rather coarse when it comes to the number of rows for RPM.

RBob.

 

Try all the above in one form or another.

Just dont ignore the AE especially if u dont have a wideband.

On my 383 TPI Formula it went from just hooking and going to sliding the rear end out and endlessly not hooking up once I got a half assed AE tune roughed in.

I will be playing with it further when the wideband temp. comes off the TTA for a little while for emission testing(did i mention it runs a whole lot better now).

I was having issues very simliar to what u r describing and also had them occur on my old hotcammed 350setup as well.

later
Jeremy

 

Where did you get the LT4 timing table? Did you import it from a different mask?

What RBob said goes against what I would initially try. I've found that most port injection run too much SA at low RPM and high load. Even with a high stall I'd actually remove timing first to see if that improves things or makes it worse. There are vss and RPM limits before the knock counts actually take out timing. For this reason it's very easy to have too much AE and too much timing to mask pre-ignition at low RPMs.
It does sound like you need a little more AE and probably more timing before the stall speed IF your bog is still present when you're cruising along at 10-20mph and you punch it (just before kickdown) with the same no power from the motor feeling.
Experiment.

 

I was going to ask about the "launch mode" to try to find out if it really is what it sounds like it is. guess so. any good literature on it that i can read up on? (i.e. what these "qualifiers" are)

 

I got the LT4 timing table from the LT4 bin. Mask $EE. I just pasted the table over making sure the kpa and rpm values lined up.
Also the first value in my AE vs TPS table is 1.32 and it slopes downward after that. Any more AE than that and it studders when revved. See the car really doesnt jump it just pulls....kind of a lack of torque feeling. I dunno...anyone in the chicago land area wanna do some WBO2 AE tuning ???? The car does have BFG drag radials on it......but still should light them up...it wont even break them loose if I break torque it to 2500 then floor it.....car just takes off.

 

Where did you get Traxion's and the LT-4 bin files from? It would be interesting to look at them.

 

Traxion posted his AE and Timing tables on the board...so just do a search on his name. I got the LT4 PCM image from a friend. Shoot me an email and I can send it to you but you need the $EE definition to look at it in tunercat.