tune problems after Dallas Performance Stage II Blower Cam

[ttbestas]

i have friend of mine drove 300 miles with his supercharged vette to get the tune from me( i have hp tuners, its prety rare in europe)
i have hard time making car run good after Dallas Performance Stage II Blower Cam install. Its bucking-jarking when of the throttle in 1200rmp in 4th gear. I put Gregs injector data in this tune, dialed the VE tables, worked on MAF, but the problem is still there. The car came with drilled TB. Any suggestions what tables should i take look? I dont wanna let him go without fixing his car. thanks

[ttbestas]

now im adding tune in 2.22 maybe you guys help

[Maikmadi]

I am that problematic corvette owner. I try to explain myself too.

With 2gear I hit that problematic area around 4000rpms, 3rd gear 2500rpms, 4th is like 2000rpms and 5th I hit like 1700rpms . It starts slowly and you can feel engine not working not so good anymore, little bit up and it makes sound like only 4 cilinders are working or something and does not react for pressing gas pedal more - so I press still more and then it goes past that after clearing 1000rpm or so. Hope you can see that on log too.

So, In city it`s not often problem - but on road if u wanna pass a car , I cant accelerate with 6th or 5th. I go to 4th and then it cleares that area fast.
It very slowly gets past that area (around 1000rpms-s maybe) and then its like in WOT mode and accelerates rapidly from there.

I had that in older tune and now with new tune. Could it just be maf table ? Maybe we didnt work it for good enough. With maf disconnected, that problem is gone and VE table is pretty good.

[Maikmadi]

These are now 2.22 logs. Also, TB is not drilled like mentioned in first post.
It has that cam, 60pounds injectors, heades,x pipe, 7-8psi boost and over 500hp with these settings.

[Con]

These are now 2.22 logs. Also, TB is not drilled like mentioned in first post.
It has that cam, 60pounds injectors, heades,x pipe, 7-8psi boost and over 500hp with these settings.

I suggest switching off the O2 off, as they are not needed for your combination, and a more trouble than they are worth.
Get your tuner to put I wide band O2 meter in the pipe before the cats, and go for a drive.
Log the AFR and you will see it going lean in those problem areas. This lean condition causes all that bucking you are seeing.
Fix the lean condition using the VE table or TPS vs RPM

[ttbestas]

I suggest switching off the O2 off, as they are not needed for your combination, and a more trouble than they are worth.
Get your tuner to put I wide band O2 meter in the pipe before the cats, and go for a drive.
Log the AFR and you will see it going lean in those problem areas. This lean condition causes all that bucking you are seeing.
Fix the lean condition using the VE table or TPS vs RPM

we have wideband installed, and the ve table is good in that range, cause when you turn maf off, SD only, open loop, the problem is not there. So i guess maf calibration needs more work

[Con]

we have wideband installed, and the ve table is good in that range, cause when you turn maf off, SD only, open loop, the problem is not there. So i guess maf calibration needs more work

Why run the MAF as MAF meters are very slow to respond.
All supercharged engines I have tuned in the past are all in SD.
Much easier as the VE table calibrates the fuel quicker than the MAF

[swebld]

Why run the MAF as MAF meters are very slow to respond.
All supercharged engines I have tuned in the past are all in SD.
Much easier as the VE table calibrates the fuel quicker than the MAF

Wow, this is really not the truth.
There is nothing better/faster than a MAF to measure air mass and VE tables are static; they do not calibrate themself for ANY changes in the engines "air pump" modeling. If the MAF is calibrated and nothing specific is preventing one from using it, it should be used.
Wow my car is running smooth as silk without MAF and in open loop VE but i still choose to use it for running stoich and extra security even if it takes time and effort to get rid of all the bucking at low speed cruise...

[Maikmadi]

I did attached tune in 2.22 also in my previous post.

2ng gear bucking: frame 88 to 99 ,then it jump off it and starts accelerating. it`s very noticeable in car..but not on logs so much. big afr spiking at happening time and timing goes low. But in car when I watched afr clock it`s was not much off, it was around 13-14 and so even when it sounded like 4-5 cilindres working...

[Con]

I did attached tune in 2.22 also in my previous post.

2ng gear bucking: frame 88 to 99 ,then it jump off it and starts accelerating. it`s very noticeable in car..but not on logs so much. big afr spiking at happening time and timing goes low. But in car when I watched afr clock it`s was not much off, it was around 13-14 and so even when it sounded like 4-5 cilindres working...

People assume you need to run 14.7 because some chemist determined 14.7 is the optimum fuel ratio. This may be true for standard motors, but you combo might like less.
The only way to determine this is put the car on the dyno, adjust the AFR up and down at around 2500 rpm and look for maximum torque.
You would be surprised, as you will find maximum torque may be less than 13.5 especially running E85. You should then tune the VE table at that AFR, and ignore the MAF and O2.
You have nothing to loose by trying. My own car had the same issues and ended up determining max torque at 13.2 and all my problems went.

[Maikmadi]

well, I have two problems with that:
after that new tune most of bucking and surging problems with idle and on driving has now gone away . And before I had totally diffrent tune in VE and in MAF and it was exatly the same problem at same area.

since I am not at my friends anymore, it takes atleast a month for now when I can maybe it get retuned... so I have to try diffrent solutions just to be sure.

I try to clean maf tough. Yesterday try`d to make exhaust also leak free.
Many cars run lean..even we drived around and afr was like 16-17 sometimes on light load.

Also I dont get lean codes ? I do get sometimes p0133 code with shows bank1 o2 responsing slowy.

[SultanHassanMasTuning]

delete the maf sensor. you will see dead on AFR's. apply the MAP and adjust the primary VE table. i have a camaro with the same problem and had a drilled TB. i simply deleted maf, licensed the map sensor and the car was great again.

[schnellTTZ06]

Where at in Europe are you? If you are around me in Germany I could take a look at it, Ive been tuning a lot of cars in my area for the past 4 years. But you really shouldnt have any problems with only installing blower cam. I was pretty shocked when I put my turbo cam in and the car still ran decent without even touching the tune and after just tuning the normal stuff it runs like a stock cam now. You may have a mechanical non tune related issue.

[ttbestas]

Where at in Europe are you? If you are around me in Germany I could take a look at it, Ive been tuning a lot of cars in my area for the past 4 years. But you really shouldnt have any problems with only installing blower cam. I was pretty shocked when I put my turbo cam in and the car still ran decent without even touching the tune and after just tuning the normal stuff it runs like a stock cam now. You may have a mechanical non tune related issue.

im located in lithuania, maik is from estonia

[blownbluez06]

problem found

[blownbluez06]

Disable the LTFT's too.

[blownbluez06]

I never think it's fair for people to come in here and ask questions, but never post the answers when they discover the problem, so here's the answer to this one. The 02's were mounted in the X-Pipe, so there was no isolation in exhaust signals and the PCM didn't know what to do.
http://www.amiflex.ee/pilt/v/autod/C...geViewsIndex=1

[Pekka_Perkeles]

I never think it's fair for people to come in here and ask questions, but never post the answers when they discover the problem, so here's the answer to this one. The 02's were mounted in the X-Pipe, so there was no isolation in exhaust signals and the PCM didn't know what to do.
http://www.amiflex.ee/pilt/v/autod/C...geViewsIndex=1

Well, Bret, I didn't know about this thread this morning when I was going through the log I received yesterday via email.

In some areas S/LTFT's were just right, then suddenly they were just like when O2 sensors are crossed. Below is a good snapshot when half of the engine has injectors open over two times longer than other side (Arrow A.).

Obviously because of O2 location in x-pipe STFT's are pushing corrections to wrong side LTFT's. Below Arrow B correction should go to Arrow C. I didn't know about O2 being in X-pipe but I was suspecting something like that (crossed O2's) must be the problem. All evidence was in fact in the scan file.



Pretty interesting case, isn't it? No wonder if colleague from Lithuania had problems last year. Now everything should be easier. :-)

[edcmat-l1]

Interesting............One year later LOL

Just an FYI to everybody, I will be in Germany tuning from July 5th to about the 26th. I'll be making a side trip to Austria as well. I'm pretty booked but if anyone needs anything, please contact me via email. [email protected].

[Pekka_Perkeles]

Interesting............One year later LOL

Maybe it's because pro's are lazy to comment. :-)