HELP WITH HP POWER ISSUE over 15psi
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Today i swapped it back to the way i started out. large pulley 84# injectors and same tune that made 600 to the tire. The dip in power was still there same rpm so its not boost related. What ever is causing this wasn't the pulley swap or the injectors or the springs. Now im more confused than ever. I even changed out the plug wires to some 7mm from pep boys in a pinch to see if i had a plug wire issue. no change! There was no knock to speak of timing was 15*
Nosmoking runs fine did a compression test 150 per cylinder on the money. I will have to do leak down next.
Im really thinking its electrical.. The only thing i haven't checked is the ECU i did remove it after the pully swap to flash it for the bigger injectors. Maybe when i put it back in i bent a pin or something.
i might also try some coils next !! I just dont get it!!
Nosmoking runs fine did a compression test 150 per cylinder on the money. I will have to do leak down next.
Im really thinking its electrical.. The only thing i haven't checked is the ECU i did remove it after the pully swap to flash it for the bigger injectors. Maybe when i put it back in i bent a pin or something.
i might also try some coils next !! I just dont get it!!
Last edited by autoaddictions; Jul 5, 2013 at 07:10 PM.
I didn't see where the above questions were answered. Which hat and filter is on it? Have you tried a run without them? Bob
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ATI ProCharger and Moser Sales 260 672-2076
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ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
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Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Update. Still cant pin this down. For those of you just tuning in the story goes like this. Dyno"d car (Mustang) made 600 hp to the tire pump gas 14* of boost no knock 16* of timing 11.5:1 AFR. Took it to the track ripped off a 10.20@132.st.
here is dyno chart of the 14 psi run power curve is smooth. There are two runs overlapped difference is one degree more of timing.
2 days later changed the D1SC pully for a smaller one in hope of making more boost!
Back to the dyno no changes other than pully. Car makes 16* of boost and has a huge drop in power at 5100ish rmp. nearly a 80 hp drop. Never made it back to 600 hp. You can hear the engine lay down a bit when the power starts to drop. No popping just sound lazy!
Dyno chart for smaller pully again no knock AFR is good same timing boost is up.
Now i have no idea whats going on here!! I have replaced the following in hopes of clearing up this mess.
Changed valve spring
PLug gap tighter
colder plugs
plug wires
Change out coils for ls2 coils.
replaced computer
replaced 2 bar map.
Now in an effort to chase the problem down i put the car back to exactly how it was when it made 600hp and now the dip in power is still there. Dyno chart looks the same no matter what we changed.
Again Air fuel is good there is no knock voltage is 12.8 steady no boost leaks.
Im at a loss for words on what to do next. Engine runs good no smoke or blow by. Hp tuners datalogs show cam and crank sensor is all in spec.
We made a pull with the blower intake tube removed naturally aspirated it still dropped power of at higher rpm.
Please help!!!
here is dyno chart of the 14 psi run power curve is smooth. There are two runs overlapped difference is one degree more of timing.
2 days later changed the D1SC pully for a smaller one in hope of making more boost!
Back to the dyno no changes other than pully. Car makes 16* of boost and has a huge drop in power at 5100ish rmp. nearly a 80 hp drop. Never made it back to 600 hp. You can hear the engine lay down a bit when the power starts to drop. No popping just sound lazy!
Dyno chart for smaller pully again no knock AFR is good same timing boost is up.
Now i have no idea whats going on here!! I have replaced the following in hopes of clearing up this mess.
Changed valve spring
PLug gap tighter
colder plugs
plug wires
Change out coils for ls2 coils.
replaced computer
replaced 2 bar map.
Now in an effort to chase the problem down i put the car back to exactly how it was when it made 600hp and now the dip in power is still there. Dyno chart looks the same no matter what we changed.
Again Air fuel is good there is no knock voltage is 12.8 steady no boost leaks.
Im at a loss for words on what to do next. Engine runs good no smoke or blow by. Hp tuners datalogs show cam and crank sensor is all in spec.
We made a pull with the blower intake tube removed naturally aspirated it still dropped power of at higher rpm.
Please help!!!
Have you checked for boost leaks? I'd pressurize the intercooler/tubing system and check for leaks. You can do this by capping off the end at the throttle body and at the blower, and install a schrader valve to one end. Several psi is all it takes to present any boost leaks. Bob
__________________
ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
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Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Trans is a 4l60 Stage 6 RPM. Trans and converter are New 3 passes on converter 12 or so dyno pulls.
Come to think about it i did drain a large mcdonalds cup worth of trans fluid after first dyno were it made 600. It was puking fluid out the nipple in the top of the bell housing. so when i got it back to the shop to swap out the procharger pulley i drained some trans fluid.I also installed a 3 ft long vacuum line to the nipple and ran it up to the dip stick tube. This allows the vacuum line to fill and drain back into the trans instead of the floor.
Mabye the trans is slipping?? I dont see how this would make the engine sound like it was laying down at the upper rpm range like it is. I would think it would sound good but lay the power down.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Have you checked for boost leaks? I'd pressurize the intercooler/tubing system and check for leaks. You can do this by capping off the end at the throttle body and at the blower, and install a schrader valve to one end. Several psi is all it takes to present any boost leaks. Bob
No way that is valve float based on that dyno graph, its too smooth. Here is valve float:
I also don't see how a boost leak would do that unless there is a leak that only opens at that rpm/boost and closes back up at anything below that level. Something is specific to that RPM in the system that causes the drop in power. Have you tried running doing a pull in a lower gear? Can you get past that rpm and do you see any dip? Can you hit 16#'s in a lower gear or on the street or does it do the same thing? I would expect you would feel that drop on the street.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
No way that is valve float based on that dyno graph, its too smooth. Here is valve float:
I also don't see how a boost leak would do that unless there is a leak that only opens at that rpm/boost and closes back up at anything below that level. Something is specific to that RPM in the system that causes the drop in power. Have you tried running doing a pull in a lower gear? Can you get past that rpm and do you see any dip? Can you hit 16#'s in a lower gear or on the street or does it do the same thing? I would expect you would feel that drop on the street.
I have not tried to make a pull on the street i didnt fell comfortable doing so knowing somthing is wrong. plus its 100 degrees out.
we did try to make a pull in 2nd gear. Hazed the **** out of the tires on the dyno data was crap.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
I didnt think it was float either. 2 days before it made good power. I figured it had 8 year old springs in it why not change them.
I have not tried to make a pull on the street i didnt fell comfortable doing so knowing somthing is wrong. plus its 100 degrees out.
we did try to make a pull in 2nd gear. Hazed the **** out of the tires on the dyno data was crap.
I have not tried to make a pull on the street i didnt fell comfortable doing so knowing somthing is wrong. plus its 100 degrees out.
we did try to make a pull in 2nd gear. Hazed the **** out of the tires on the dyno data was crap.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 97
Likes: 5
From: Blackwood NJ
Got it figured out!!!! After a perfect leak down test and compression test.I decide to get a fresh set of eyes on the problem. I took the car to Matt at Tune Time Performance they did some quick poking around and realized the fuel control was not working like it should. It was 11.3:1 even at idle, and could not be leaned out further. There for it was decide to disconnect the injector driver and swap out the low z 83# injectors in favor of some 72# high impedance ones they had in stock. Matt adjusted the tune up for the new injectors and problem solved.. No more mystery dip at 5100 rpm.
Looking back to when i did the pully swap for more boost i also installed a set of used 120# low z injectors i bought online. Two where stuck wide open and i sent them back to the seller. I got brand new ones after that. However the bad used ones must of hurt the injector driver. So even though i bought new ones the damage was done and it wasn't right since.
So now back to the track on friday night to try and best my 10.20 et.
Thanks to all for the help and suggestions!!
Thanks to Matt At Tune Time For Diagnosis!!
Looking back to when i did the pully swap for more boost i also installed a set of used 120# low z injectors i bought online. Two where stuck wide open and i sent them back to the seller. I got brand new ones after that. However the bad used ones must of hurt the injector driver. So even though i bought new ones the damage was done and it wasn't right since.
So now back to the track on friday night to try and best my 10.20 et.
Thanks to all for the help and suggestions!!
Thanks to Matt At Tune Time For Diagnosis!!