I have a buddy that when he shifts to the next gear mostly to 2nd and to 3rd the car falls on it's face and completely out of boost back to vacuum when checkin datalogs. He is revving high enough it just seems to do this every time most noticed in those 2 gear changes. Anyone have any opinion on what could be causing this or things we can check?

 

what size turbo is he running? Sometimes setups with big turbos will do this becasue inbetween shifts,you have to "re spool" the turbo back to the desired boost level. if the turbo is quite big,your probably experiencing a big drop between shifts.

or could be that between shifts your buddy is running extremely rich. What happens is the car is tuned,blah blah blah. your tune could be fine,but when your cramming loads of air/fuel into the motor,then shift,your losing air pressure/mass due to the BOV just releasing all that air into the atmosphere,but still spraying all the fuel into the motor becasue the computer still thinks all that air is still being inducted in. So for the first second after a shift,the car will kinda "bog" until it gets that ratio of air and fuel back to what it was tuned for.

 

Not to sound like an ***, but if he's shifting like grandma this will happen on cars with decent size turbo's. Have you seen him shift before? Is he pretty quick? That is my first guess.

Check all the cupplings on your charge pipes for leaks also.

 

tell him to pony up, slam gears and full throttle shift. does he have a retarded light flywheel and a huge turbo?

 

Maybe he is probably spinning the tires and when he sees the tack go near the limiter he shifts into 3rd gear of his LS tranny when its only going maybe 40mph. Maybe? LOL.

 

turbo is a gt3582r. I'm running a 35r on my setup also but not experiencing the problems he is. He is a good driver and has even tried full throttle shifting and it does the same thing. the motor is built and revving high enough not to bog it. It's spinning out in first but he is riding it out off the rev limiter so it shouldn't be bogging. Just redone all the vac lines so nothing bad there.

 

hahaha.....i read this thinking, wow i'm having the same problem, then realized it was about me

 

it happens mainly from 1st to 2nd, and i thought i was loading up with fuel, but from my understanding, when i bounce it in first to get up to speed while i'm spinning, it is fuel cutting, so if anything there would be the lack of fuel...

before anymore major events i plan on taking it out to the track to see if i can't figure out the problem....

 

how much is the boost dropping between shifts? possible tuning issue?

 

Wouldnt the extra fuel between shifts keep unburned fuel going through the turbine housing thus keeping the turbine wheel spinning decentley?

Anyways, what size exhaust is he running? I took my car to the track with 2.25" exhaust and a lightened flywheel, and spool took a CONSIDERABLE amount of time between shifts.

You shoudl also note that with a big turbo you really arent putting much of a load on the motor, so your building very few pounds of boost (if any). Also it might help to bounce off the limiter in 1st a lil longer

 

i was having a simular problem so i took my tuner for a ride. come to find out, i was hitting fuel cut because the turbo would spike slightly from hitting rev limiter. i turned the boost down like 1/2 psi and it fixed the problem.

 

What size is his exhaust. A restrictive exhaust will result in slower speeds in boost transitions, i.e. gear changes.

 

.82 a/r housing, full 3" all the way back, and its not hitting boost cut because it will do this even when i'm on low boost, like 14 psi, and my boost cut is at 30psi

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .adam. &raquo;</TD></TR><TR><TD CLASS="quote">it happens mainly from 1st to 2nd, and i thought i was loading up with fuel, but from my understanding, when i bounce it in first to get up to speed while i'm spinning, it is fuel cutting, so if anything there would be the lack of fuel...

before anymore major events i plan on taking it out to the track to see if i can't figure out the problem....</TD></TR></TABLE>

What transmission?

If it's an LS, that's why. There's too much of a difference between 1-2. Happens in my car too and it's really annoying.

 

gsr trans

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .adam. &raquo;</TD></TR><TR><TD CLASS="quote">gsr trans</TD></TR></TABLE>

When does the turbo spool, how high are you revving, and are you lighting them up through 1st consistently?

 

im lighting them up pretty good all the way through first gear and letting it bounce off the limiter for a while to get up to speed, i get full boost before 5500 and i'm revving to 9k

 

I fall out of boost pretty bad while shifting especially 1-2nd.. my rpms drop a ton in that shift.. I hate it.

I am running a 60-1 .70 .63 .. 9:1 gsr with a super light fly

So I bought a GT3082r .70 .82 dbl ball bearing, putting stock fly back in and configuring my full throttle anti lag shift ... hopefully this fixes my problem.

dk

edit I have a GSR tranny

 

It's not the turbo size trust me. I've rode in others not revving as high with pretty much same setup same turbo and it stays in boost through every shift.

On adams setup when he dataloged one of the runs it's completely falling out of all boost back to vacuum -17.

sorry Adam I had to post this up it's been buggin the hell out of me since Cleveland IFO.Maybe need to try a boost leak test to see if anything is cracked or maybe intercooler pipe is loose or something.

Here is something else to consider. Even when the switch is on for the secondary map (high boost) it is not boosting any higher than 14psi even though in the hondata datalog it is showing that the secondary switch is on so it should be boosting higher. Also every shift that is made it shows the secondary switch shuts off. The secondary switch is just for low/high boost so shouldn't that stay on through the shifts?