New DP, low boost

[motorhead]

I cannot recall but does the Power Logger show IDC% and injector PW?  These would be good indicators of either commanded base fuel being too high (high DC%), or an alky over run (low DC%).

[good2win22]

I cannot recall but does the Power Logger show IDC% and injector PW?  These would be good indicators of either commanded base fuel being too high (high DC%), or an alky over run (low DC%).

PL displays both of those parameters

[good2win22]

Shimy, this thread has been of great interest to me. A couple of months ago, I had someone asking me for help and eventually he put an alky kit on it and the car was too rich.  I never got anywhere trying to help him because he could not follow instructions and never would do all of what I asked him to try.  I think he could make boost, but he kept setting the boost to 18 psi instead of increasing it to see if the car would lean down with boost. 

then, you came along and could not make the boost it should...you had the alky kit and a new dp.

Two weeks ago, I finally got around to installing the alky control kit to replace the old SMC kit that died a couple of years ago and which I had rigged with various pumps, etc.  I also installed a new boost controller.  I did not have much time to play with it but when I did the other day, it was showing O2s ranging from 860-900 and would only pull 22# of boost.  Shades of Shimy!  LOL

I was convinced it was the alky kit but I turned it down a bit yesterday and it was still running 850-860 and pumping black smoke with no improvement in the boost.

I played with it a bit yesterday and started playing with the fueling in the chip yesterday and this morning and got it down to about 830.  I noticed that it was running well in the 800's before the alky came on at light throttle so I have begun to look at the chip settings.  This is an SD chip with a million settings so it is not simple to just pull fuel out without some careful consideration.  I don't have a wb on the car and don't think it would help.  I am running open loop.  I don't recall ever having much problem setting it up or it being so rich. 

Fuel pressure seems to be working properly but I am going to put a different gauge on it because it seems to be rich all the way from beginning to end.  I put the old controller on it and that did not help the boost come up.  My computations say that another 3psi of boost might bring the O2s into line...but, computations only count when they work.

I will try to find my other gauge tomorrow and I am going to wire the puck shut. 

so don't get discouraged, it happens to all of us...at least to those of us that are honest!  lololol

I think everybody knows but the parts # for the hd actuator should be 1011-144

Very well said Steve!  All the power plants may be the same but the settings to get them to run where you like may not be the same. My engine combo doesn't like a WB leaner than 10.8 with alky.  I still monitor the NB and with that 10.8 on the WB, I see low 750's on the NB at peak rpm

[Steve Wood]

Jason, that sounds right to me.  Serious combos on alky are going to run quite a bit lower on A/F than they would on race gas because the stochiometric valve for methanol is much lower than that of gasoline...and when we run a blend of the two, we have a stochiometric point that is more like the average of the two when we take the percentage relationship of the two fuels into account.  Some will tout the value of referring to lambda rather than A/F, but as we have a variable mixture, I prefer to use A/F and find out what is the magic number for our particular combination.  Please feel free to punctuate the prior as you like lol

As you crank it up, you may find it likes 10.6 even more.  In the end, we tend to forget specific numbers and just give it what works best no matter what the next guy in line says!

[TexasT]

h

[Shimy87]

Laid awake last nite thinking about this...yes I obsess.....bee n chasing my tail so back to basics. I struggle finding exhaust leaks so I tried my shop vac idea blowing in the tail pipe and spray soapy water at connections. Well got no bubbles on drivers side header or crossover connections but did get small ones on back port  passanger header and some at turbo connection. Pulled turbo and header, cleaned it all up and replaced gasket, siliconed crossover again and turbo connection, reassembled. Dont know if these were significant enough to cause trouble but its a start. Will test again for leaks tonight with same method.

[Steve Wood]

obsessing is much easier than busting your knuckles

[Shimy87]

Im getting way to good at taking this thing apart 

[Steve Wood]

 

[good2win22]

Im getting way to good at taking this thing apart 

Practice makes perfect.  It makes it a lot quicker to repair when you know what size wrenches/sockets you need before climbing under the car

[Scoobum]

I pull fuel till I see a hint of KR at the traps and the 1-2 and 2-3 shift. There's no magic number. For MY engine...750 is about as far as I can push it. Low 740's...and I start seeing KR. No 2 engines are alike. I've never paid attention to what Joe Blow says about a magic WB number.

[1 RARE T]

Crank the waste-gate tighter.


Being a little rich is'nt killing the ability to make boost.

Would you explain to us how cranking it tighter will make more boost when wiring it closed will not?

He makes 19-20 psi with everything hooked up.


Wired shut it only made 15. It was'nt wired completely 100%.


Back up. Old downpipe,wastegate, set up made 24-25 psi.


Swapped out new stuff, boost goes down.


If there were exhaust leaks, they've been there all along.


He has stated that turning down the alky does nothing to the boost level or A/F ratio.


My suggestion is that the wastegate rod needs more tension because I think it is lifting off the hole with boost.


That or the puck just is'nt sealing well at all.


 

[motorhead]

My money is still on a misaligned flapper arm.

[Shimy87]

Houston....we have boost!!!   First pull with WG arm set at 1/8 and boost controller in the middle and got 18 lbs..   Stopped.... maxed out WG arm and shimmed boost controller and maxed it out, shot to 25 lbs and had to lift as alarm screeched. left WG arm and backed controller off 2 turns and on a 3rd gear pull from about 50 to 90 I get an initial boost spike to 23lbs and then flutters between a lowest of 20.4 and a high of 22.7....all on powerlogger. weird thing is the power logger shows this flutter reading but boost gauge shows the needle swing between 23 and 22. No knock as chip is on defaults and alky is back to delivered settings. you can feel the boost flutter in the seat of pants. end of run I'm at O2's of 811

Is this boost fluctuation normal? How can I smooth it out? I'd like to get a nice steady 24 lbs if I can.

As always, thanks for any help!!

[Steve Wood]

Sounds like the wastegate spring is weak....The actuator should not see boost until the boost controller allows the check ball to move off the seat.  In this case, it sounds like pressure behind the puck is overcoming the spring pressure of the actuator and opening the puck a bit.  The danger of shortening the actuator arm too much is that it limits the distance the puck can open and a large turbo will overwhelm the puck with volume and allow the boost to creep on up because the puck is not open enuf to handle the volume.  (Note that sometimes we want the boost controller to open at a lower boost than the puck in cases where the tires will not handle being hit with such a high boost on launch)

As suggested by someone prior, a helper spring on the wastegate arm might allow the puck to open more at a higher boost and it might also remove some of the flutter from the puck. All this with a longer wastegate arm setting.

Enlarging the wastegate hole and puck size alter  the physics of the matter.

Take three numbers out of the top gear fueling and see if you can get the O2s down a bit more..that may also help the boost fluctuation... which is not uncommon and it's hard to know if it is from the puck failing to stabilize completely or if the map sensor is completely stable in output.  Sounds like the puck to me as you said you can feel it.  Changing the fueling may have some affect as well.

Glad to see progress!