Im having a similar issue. I swapped in a test pipe to replace the stock cat and dyno showed I lost about 5 hp, lol. did a retune that same time on e85 and gained only marginal hp, gained tons of torque though. Im finding I developed a boost leak at 15 psi and another at around 25 psi. Im just trying to find time now to work on the car to fix it. Definitely do a boost leak test if you haven't already. Also, could an exhaust leak cause this power loss?

As stated above, I think its BS when tuners/shops get all butt hurt when you ask for your logs, and instead of being able to diagnose something just point to something that MAY be a restriction and use that as your scapegoat.

Im not trash talking, but, tuners, from my experience, seem to be very knowledgeable about the tuning portion of cars, but when it comes time to the mechanical and diagnosing, if they cant do it via their laptop they seem to get clueless. Im not bashing all tuners, like I said from my experience in general. It just seems to be the exception not the norm, to have a tuner be also a great diagnostic tech.

 

true.

 

If Iveytuned tunes my car and it showed he was dumming down my car, I'm opening a small claim suit. Someone thinks they can just take 600$ and it's not a big deal

 

Data logs a very important. I wouldn't buy any more parts until a leak down and compression test are preformed so you don't look foolish. Also make a boost leak tester and ensure their is no boost leak. Check that your timing is dead on as well. What was actually done to the head. How is the car running as asked in previous statements ?

 

I will do it man. is your money

 

Has he still not replied?

 

No responds to texts or phone calls. Unbelievable

 

sorry if i missed it, but are you running a cat?

if so, drop it & shine a light thru it, to see that it isnt clogged.

back pressure kills power.....

also, can you verify your exhaust wasnt hit by a rock & dented?

it would be interesting to see a power curve

 

Clogged cat would kill power but the car would run horrible. Dent in the exhaust shouldnt kill 50+ hp
Also you should def invest so you can data log on your own as you can see right from the get that he is down tuning the car which i wouldnt think he would do but i have not heard any great things from ivy tune. Post some data logs so we can see what the deal is. 400 hp is very doable with the mods you have as ams gives you cams full exhaust and an intake for 380.

 

If back pressure was the issue, boost cut would be present. There's no way his exhaust system is killing that much power...

 

Noone on this forum is gonna be able to assist you with out any data logs. Right now these thoughts are all hear say so please put up the data logs so we can see the real deal https://www.evolutionm.net/forums/showthread.php?t=415240
Build the cable its not bad

 

Explain that one to me...

 

If there's enough back pressure then you can't make more than "x" amount of boost and you would get a boost cut... Even if the back pressure was not enough to cause a boost cut issue, you would have problems building boost.

 

I didn't see it mentioned so ill shoot it out there, have you considered checking on the cam timing? Sometimes its a little off of what the spec card reads, which is why most engine builders will degree the cams when they install them.

 

Ok, I thought you were referring to fuel cut due to overboosting since some persons term it boost cut.

With a significant restriction you may still be able to make normal boost but the turbo efficiency will be seriously reduced and hence power will be reduced.