I am having ittermitten problems where I loose boost psi on my car.

Car has a silenoid boost controler via the ECM

Automatic tranny, 2800 stall converter. Runs 14.00's with the loss in boost. 3.1L V6 Trannys in good shape, just took it out a few weeks ago for a inspection/also installed converter

Right now im running 12.5 command psi and heres what it will do in the 1/4 mile.

I will go down the track fine but when shifting from 1 to 2nd I loose a few psi then it comes back in to full boost fast, then when it shifts from 2nd to 3rd I loose even more boost, as low at 7-8psi and my full boost is 12.5. So im loosng alot of time in the 1/4 mile. This is a ittermitten problem and doesnt happend all the time. As you can imagin going from 12 to 8 psi is a huge difference that can be felt. Its a smooth loss in boost thought, its not like its hitting a brick wall or anything like that.

Im just looking for open ideas of what to look for and how to troubleshoot better as I have not figured out what the problem may be.

Thanks for any ideas or tips on this problem.

 

It might be misfiring. hows your ignition system (spark plugs ,wires ,coil).
it could be a hanging injector but most likely the problem you have is in the ignition.

 

No ideas?? Heres a excel format datalog to see the boost droping. Youll see it drop 4-5 psi then go back up.

 

Let me add, yesterday on one run I ran great then after about 80mph I litterly was stuck on 5psi of boost, it just dropped there like to blew a coupler...so i let off thinking I busted a coupler but didnt see any problem. Then I made a good pass, then after that one I literly was stuck with 5 psi again but from the start of the race, that was embarrasing.

I then got in the pits and floored it with the brakes on a few times and then all of the sudden the boost went back up to normal?? Weird.....

Wastegate problems??? Sticky?? Are these the areas i should be looking at? As I could clearly hear the turbo spinning alot slower when the boost was low.

 

i forgot to ask u when the wastegate is hooked up without the boost controller how much boost does it make ?

u may need a stiffer wastegate spring, also were is the refrence line to the wastegate hooked up

 

1-2 shift is at 6k rpms , the shift bottoms at 4,500 rpms
2-3 shift ghappens at 5,900 and rpms drop to 4450

try getting a stiffer wastegate spring

 

try this spring
http://www.ebay.com/itm/35MM-38MM-44...#ht_2264wt_932

 

Went out and tore to wg down to look at it again, The only thing I see that could be wrong is the valve that opens had alot of carbon on the surface that meet the seat. You know the little ring they have on it?? I used some valve lap stuff to smooth out the carbon on the valve and the seat of it... just as it was a valve in a head. Put the stuff on there and spun the ring arround on the valve till shiny and smooth mating surface.

The reference line is right off the turbo.

I have yet to look through the controller wiring as I ran out of time today. So I want to do that first. But a larger WG spring is probly needed. Its "suppose" to be a 8lbs one in there but ive never seen it get that high, more like 5-6psi without the controller hooked up. Thats what made me think I may have a loose wire when the car didnt have boost all of a sudden on one pass

But the way its atcring when I shift is what im woundering, as that does not sound like a wiring issue.


15lbs springs a little stiff?? Im thinking more like a 12-13lbs one as my fueling is getting close to max @ 12.5-13psi

 

that seller has a 12 psi spring as well, i showed u the 15 psi spring cause usually the ebay springs dont make advertised boost there usually a few psi lower then what they say they are

so i figure the 15 psi spring should make about 12-13 psi


also the spring is ur problem u can only dbl the base presure of the spring
if spring only makes 6 psi without the boost controler u can get 12max out of it with a controller like ur using
7=14max
9=18max
its typically 1-2 psi less then dbl the springs rated presure though



the onyl way to get more presur eout of the spring is to use a boost controller that plumbs into the top port as well

ur boost controller just regulates air to the bottom of the port what happens is the controller lesses the amount of signal to the bottom port to raise boost presure well eventually the ex presure just openes the wastegate valve since the spring itself cant hold it shut

 

Ok, so why would it be able to make the 13psi but fall off when I shift gears?? Thats what I really dont get... im lost on why this is happening sometimes and I can hold boost so long but as soon as I shift... there its goes down the drain then builds back up. It even does it in 1-2 shifts.. 10-11 psi then drops to 8-9 then back up to 10-11-12 full boost.

 

the ex backpresure is overpowering the spring on the shift
and when the boost controler valev has the line presure to the wastegate down the sudden dropoff of presure on the refrence line makes it worse

try the new spring without the controller and it prolly wont drop off

i saw the same kind of dropoff with mine till i put a 1/4 spacer in the top of my wastegate to compress the spring and make it stiffer,
though my droppoff wasnt as bad

 

Ok ill go ahead and get the spring. What kind of spacer did you rig up???

In you opinion will it help spool up time also? j/w

 

was a piece of roundstock that fit in the top of the wastegate housing that was 1/4 thick

yeah it will make it spool faster

if u have time now try to shim the spring with something and take the car out and see if it fixes it

anything that fits in the wastegate top will work just make sure it dosent block the top port hole in the wastegate top or the wastegate wont open

i.e just drill a large hole threw the shim in the middle were the top port is so air can still get in/out of the wastegate top

 

Ok dave im going to rig something up and see what happends... should I not hook the controller up for this?? Just so see what it does? Also 1/4 inch you used. What was the effect in psi? Just want to make sure thats not too big or small for what im doing

 

large fender washers work well

 

dont use the controller so u can se ehow much the boost comes up first, 1/4 inch got me 3 psi i belive

 

ok ill be back on later

 

Does the spacer have to be on the top of the wastegete spring?? There not much room up there to make sure the outlet port isnt blocked.. I have a nice spacer made up and though of just putting it on the bottom part insted?

 

it can go in the bottom to as long as the spring can sit nicely on it, for me it was easier to put the spacer in the top

 

Ok dave that might have been the answer.

With just the stock wastegate spring normal=4.69psi of boost max
With the 1/4 shim there 6.19 psi max all day.
Held at those numbers when WOT.

And if you can look at this log(i didnt just floor it so I eased into it, didnt wana just burn out when the flash power kicked in).. This is with the shim and boost controler. 12.5psi

All of the sudden my injector duty cycle isnt so high and the AFR is a little rich in areas?

Felt much better in the transitions between gears, if anything it shifted harder now, or at least felt like it. This is with the exhaust cut out on, so it had more restriction then at the track but felt faster with the shim! I cant say for 100% certain that this was the problem as I only made 1 0-110mph run but even just gassing it through 1-2nd on the road felt good and a tad better responce from the turbo(less lag)

The shim will work for now, but Im ordering a spring tonight. The one you linked should do.

 

so boost didnt drop off?
if that fixed it order up that new heavier spring

also did u get intouch with the guy witht he gears, are u going to get them?

taking a look at the log now

 

what color spring was in ur wastegate ?

boost fell off on the 1-2 shift by 2.5 psi but came right back, no boost drop at all on the 2-3 shift


u can try shimming it a lil more until u get a new stiiffer spring in there

 

The boost dropped ever so slightly for 1st to 2nd but when it shifted into third I actually over boosted... almost 14psi!! Stinking rich as ive never tuned for that high.

I didnt call the guy because im working on this kid that has a eaton unit with 3.42 gears that hes suppose to be taking out of his car and selling to me cheep. Hes throwing in a 9in ford rear on his race camaro. So im hoping that pans out in the next week or so.

 

The WG spring really wasnt a color?? It was just metal..LOL grayish black. If I shim it a tad more will it mess up the opening gap??

 

it prolly had a lil color on one of the ends of the spring

if u dont hear form that other guy with the eaton get ahold of the kid with the 3:73s for 30 bucks they wont last long


i think the log showed 13.3 psi i didnt pay to much attention to the boost spike, which i forgot to mention may happen with a shimmed wastegate spring,a nd once u open the cutout again the spike shouldnt be as bad

now that the boost issues figured out if u launch good u should hit bottom 13's @ around 106 mph pretty easy

 

Yea the car felt much stronger(the spike was 13.79psi.
On some of the runs...the 14.05 pass this morning I went from 12.9psi to 7.41 when I shifted from 2-3rd...

I may go on wednesday but I have to go get my slicks from my buddys traior since I dont toat them over there im my car.

I launched better today.. 60ft times were all mid to low 2.10's thats better considering me learning how to do it.

 

Dave, also my WG looks like that one on that link you sent me, it has both inner and outer seals... So that links for the outer ones right? Im about to order the thing insted of constantly adding shims to make me happy..lol

 

yes u can shim it a lil more just test it without the boost controller anytime u shim it to make sure boost dont creep or go way to high

that spring is on the outer step., the spring u have now is it on the inner or outer step?

they are mad eliek that so u can run an inner and outewr spring together to fine tune the wastegate

i.e a 4psi inner spring with a 9 psi outer spring etc etc

as long as ur wastegate looks like the one in the picture the spring will fit it

 

thats what it would look like if u ran 2 springs

 

Ahh I see what you mean with the double springs now.

The one I had was on the outer step, but did have the extra step for the inner one.
I ordered the spring so will just leave the shim as is for now. All this makes me think I have a good 2-3psi drop getting to the Tb/map sensor area. Probly my sad excuse for piping....lmao

When I ran the car without the controler it wouldnt spike, just stayed at 6.19psi..literly stayed there.

The boost spike could be from my controler DC since I was jacking it up trying to over come the boost loss.

Dave Its hard to actually base times off that log but from 1mph to 100 it was 13.5 seconds.. I feel better now that im getting all I can out of the turbo and the boost. Crap was driving me crazy at the track yesteday!!!!!!!!!!!!!!!!!!!!!!

 

the times in the logs are pretty damn close just time the log and match it to ur time slips

the only thing that wont match is the mph since mph is calculated on the last xx feet of the track

 

Yea and my slicks mess up the speedo.

The only slips I can compare to is from the 14.37 pass on street tires.

Ill just look at the 1-100mph on the shimmed log and compare it to 0-100mph time on the track with street tires.. And thats consdering that I eased into the throttle just on the last log tonight..


These times are based off of the datalog not the timeslip
14.54 0-100Mph on the 14.37 second pass with street tires.(the first time at the track this year)
13.51 1-100mph with the WG shim on the road with street tires.

That new spring wont be here for a week so I hope that shim holds up till then at the track. I may have to add just a little more, not much though.

 

its prolly aorund a 13.7 second 1/4 mile u have to read the mph a lil higher then what ur timeslip reads ( 2-3) mph will usually be damn close

like ive been telling u ur car is a low 13 second car as is just need to work out the issues and get a good launch

 

I know, After seeing a few 8.8'-8.9's in the 1/8 mile yesterday I knew it wanted a 13's sec 1/4 mile as it really takes off after the 1/8mile but that loss in boost was killing me.

Cant wait to get another shot at it later this week. Although yesterday was the perfect day 50* out. Nice for turbos!

 

Well you can tell I was tired yesterday. That WG spring was on the inside grove, also there is not tag or color of any sorts on the spring. That is a cheep spring!

I added another thin shim in there, didnt do any thing same psi as with the original shim I used yesterday, so Ill just put that shim back in and then re route the boost reference to the intake insted of the turbo hopefully that will hold up till the new spring gets here. Im going to the races hopefully on wednesday after work.

Heres the gate I have, the more I read Im really doubting that there is a 8psi spring in there. Crap man, I could only make 4-5psi max with the wastegate by itself
http://www.ebay.com/itm/35MM-VR-STYL...item3a5b9f8069

Wg base


Spring in WG grove, no markings whatsoever on the spring pressure. The new one will be here in a week.