ok guys so i finally remembered to make this post cause i need some help with this so here it goes

ok so originally i got tuned for 21psi on 93 octane with all my mods no cams stock turbo on an 05 VIII, car made power and was great, i noticed that if it got a little cold and the boost went to 22psi that the car would almost hesitate on its climb thru the rpm range, this would only happen at WOT no other time and would stop if i let off throttle even a little if i turned boost down to say idk 19psi it would be gone all together, so recently i tryed tuning it myself for 24psi no knock and a conservative AFR , the hesitation is now always there if im WOT its almost as if sumone was pushin the brakes just the tinyest bit on and off and on and off when im WOT if i lower boost to 21psi its gone and doesnt do it at all, its a very smooth powerband that im actually surprised that i accomplished on my own(the only other time it wont hesitate is if i do very very repetative runs at almost WOT then i can do WOT no hesitation), thing is i want the extra 3psi, what is making me post up is that when i log it, there is literally no knock not a single count (if i tuned my own car and it blew up...i would never hear the end of it) so i really cant understand whats going on

note:: car is always up to temp both coolant and oil before doing anything

has anyone ever encountered this and if you did what eliminated it or what did you find was the problem, any input would be awesome guys it sucks n it bothers me

 

Possibly spark plug blow-out.

Check plug gap, should be around .023-0.25

NGK BPR7ES or BPR8ES are cheap enough you might as well just swap in new properly gapped ones.

 

brandy new BPR7ES's in there gapped to .024, i mean ill pullem and check them but i did them about a week before i tuned it and it had always done it im just finally fed up and wanna get rid of it

 

What is your AFR? Could be too rich?

Done a boost leak test?

 

i lent my AFR gauge and wideband to a buddy to tune his car, ill get it back in a couple of days as far as i remember it was 11.3 @ WOT and there is no boost leak, this im sure of. im thinking it might be a litle too rich, maybe ill see what RPM it happens and try re interpolating the fuel tables...if i encounter any knock ill just reload my current map an back to square one again lol ill post an update as soon as i can, ill see if i can do this on my way in to work tomarrow

 

Could also be a quick onset of large amounts of knock.

 

Post AFR log.

 

You should do the Knock CEL patch and see if you get knock during a pull (makes it easy to see). Maybe the increased boost is creating knock and pulling timing making the car stumble.

 

do you have any logs? check out what your timing is doing. is it bouncing all over the place, even without knock?

 

ok everyone is saying the same thing so im going to reiterate it again ....

i have not a single count of knock anywhere in the entire rpm band, when i log i do 3 consecutive 3rd gear pulls then a 1st-4th pull and i have no knock, the timing cant be pulled because i have no knock(as far as i know lol), i dont/cant log my AFR's, i eyeball them to watch where they stay, i didnt have a chance to reinterpolate my fuel tables, today do to the fact i got pulled over on my way to work and any time i was going to spend with the car was used to debate why i should get 3 different tickets (i got none), so i will post reply as soon as i try this

 

So no knock. Check.

What is you timing doing, have you logged your timing to verify the values. Timing can change for other reasons, there are some older threads about it. I'd post a log yo.

 

didnt know that timing could still change i will be sure to log timing and post up the xml file for sum review

 

check your timing curve check if its a smooth transition. post up your timing maps and logs

 

dude... you own an Evo. unless you have all 3 maps set the same, your timing will bounce around with or without you logging any knock. thats why so many tuners set all the maps the same. I can make multiple drag passes, and my timing curve will be different every time... no knock. so now you know.

 

dex mix, if you look under my user name it says Drives: 05 Evo VIII

i know i own an evo...do you know that 03-05 evo VIII's only have 1 high octane map and 1 low octane map, both for fuel and timing?

now you know