well i installed a twin turbo on my bosses truck which use to have a p1 procharger we took it off and went with 2 t67 precision turbos truck works good while cruisin mode but once i try to floor it kind of backfires i cant even go half throttle when this happens they told me to go with a 2 bar map sensor i just installed it just need to get it tuned hopefully tomorrow but would that be my problem?? the set up consists on 6.0 lq4 with l92 heads,l92 victor jr,ls7 cam,fuel system went with a 255 walboro fuel pump! i just dont understand how com i didnt have this problem with the procharger?? we tried the tune and it and it only reads up to 105 kpa so i just installed the 2 bar and hope that will be my problem the injecter duty cycle was reading like 22% and was still showing lean im new to turbos set ups thanks for the help

 

If it ran fine with the Procharger p1 it should be a good starting point for the twin turbo tune. My guess it is it the intake plumbing or the waste-gate operation. If that all checks out then:

Are you running a MAF?

Could be you are seeing too big of an air flow increase in too short off a time. If you have a DBW TB then you may need to adjust the tune because it is going out of reference.

A 2bar MAP will require a Custom Operating System or all tables referenced to MAP will need to be scaled for the increased signal as the tune will now see 105 kPa at one/half the previous output voltage. The kPa reading of the MAP will double but the same 0-5v output of the sensor will remain.

 

As Mort stated, you need a COS to make ANY use of that MAP sensor. You're lean as you know. Stay out of boost until you can get that tune worked out.

 

You can NOT run the 2 bar MAP until you have the tune set up for it.

 

thanks ppl for the reply im not using the maf any more so i think i got the idea ill just wait to actually tune and go from there and now i do understand why with the procharger it was working and that was because i was using the maf and now with the twins the maf got eliminated and my map should do the work! i appreciate ur responses and glad to have had this help!!

 

did you tune the MAF out or just unplug it?

 

we unplugged it!! we didnt have time to play with it today probably tomorrow but i will have u guys updated