dville_gt

iTrader: (5)

Just got my LQ9 Turbo Mustang together and it can't seem to get into boost without going crazy. It is a T6 Borg Warner S474 turbo, and a COMP xfi 230/230 cam. I don't have any real good logs, but I will post what I have (can only drive the car around outside the shop so all the runs are in 1st (th350)). Car does fine up until around 3500 rpm where it starts breaking up really hard and falls on it's face.

Car has 80lb (@3bar) injectors
TR6 Plugs gapped at .030
Stock LQ9 w/stock 317's
B/W S475 w/4in intercooler
Th350 with custom built stall

On a side note I pulled the plugs to check gap and number 7 was covered in carbon (and number 8 was half covered in carbon). The car ran great when it was all motor (7.0's w/just a cam (tsp tsunami). Only things that were changed are the turbo setup, cam, fuel injectors, and converter.

One of my buddies who is a turbo guru pointed towards the plugs saying the TR6's are way to hot (recommended something in the 7-9 range) and that I should go with a non-extended tip. He sounded pretty confident that this would solve my issue, but I see tons of turbo folks running on TR6's and the fact is I've only built 2lbs of boost per my logs. I have trouble believing that TR6's cant work w/2lbs of boost.

I have the 6lb springs in my wastegates, but the car falls on it's face way before I ever get there. It runs up in the RPM's like all is well then it just breaks up so hard that you have to let out of it. The plugs weren't new when they went in so I don't know how much faith to put in there readings, but all of the other plugs were a slight grey (almost looked a bit lean), and the rear two (especially number 7) had a good amount of carbon all over it (not oily, definitely carbon).

The injectors were just rebuilt (and resized) so they should all be good, but I guess there is a chance something could be wrong with them although the car seems to idle fine drives fine out of boost. I am going to swap the injectors to different cylinders to see if the problem moves or not. Seems really strange I'd get two bad injectors and they'd both be on the rear most cylinders, and it seems like the car would still gain rpm even if one or two injectors were acting up.

The only other thing I can think of is some electrical problem? I am getting all of my vacuum sources from the rear of the manifold if that could make any difference (tapped the ls6 manifold and using a vacuum block for distribution).

Any ideas on what to check. I uploaded a log file over on HPTuners forum.

HydroStream6

iTrader: (16)

Lets see the logs. Also, I'd get some BR7EF plugs, gap at .022". This is a non projected plug and is one step colder than where you are now. Gapping them tighter will rule out plug blowout. This is a $20 change and will rule out plugs.

Also, what valve springs are you running and what is your AFR when it starts breaking up?

pwrtrip75

iTrader: (8)

Sounds like your plugs are shot...

What are your A/F ratios across the chart?

dville_gt

iTrader: (5)

The air fuel is around 14:1 then when it goes into PE goes to right at 11:1

HydroStream6

iTrader: (16)

Do what I suggested with the plugs and then get back to us. Also check wires.

SATAN

iTrader: (2)

I agree. I think changing to brand new plugs and gapping them way down will be the thing most people will agree on as the first thing to do. You already said the plugs were not new. So start with new plugs to rule them out. Worst case scenario, you just replaced your old plugs with new ones.

pwrtrip75

iTrader: (8)

11:1 at what kpa? If that is JUST getting into PE and not boost yet you are rich as hell. Even at your 6lbs of boost that is pig rich. Sounds like you are bringing on way too much fuel way too soon. Going into PE what I aim for is 12.2:1 at peak Torque of your power band and then lean out to 12.8:1 as it goes up.... then when you start getting into boost only 6lbs I would have it drop down gradually to 11.8:1 to start. That would work to get it drivable... then fine tune it from there.

dville_gt

iTrader: (5)

at like 100-120kpa, thats as high as I've made it before it starts bs'ing. I am going to throw in some new plugs tomorrow and see if it helps. I've also read another thread where someone recommended taking off the metal plug boots. seems counter intuitive, but the guy who posted said they were arching only under boost.

tomz28

iTrader: (20)

Tr6 plugs work just fine for me and at your target boost level I have a hard time believing your problem is in the plugs.are you doing your own tuning. pm me your number taking is allot easier for me. I.tune my ride so I might help you find something to get you in the right direction

WheelsUp84z

iTrader: (14)

Its gonna guess the plug gap.. .030 is quite large. Had the same problem on the last car I was tuning, they were gapped about the same as that, and it was getting spark blow out. Regapped them at .020 and the problem went away.

skinnies

iTrader: (33)

what coils and how much timing?

HydroStream6

iTrader: (16)

I still don't see what valve springs either?

tomz28

iTrader: (20)

Chill out guys the car has never been tuned for boost. Let's start with that

dville_gt

iTrader: (5)

Springs are Lunati .660" spring kit

Coils are stock '05 lq9 coils

timing ramps down from about 20* at 3.2k rpm to 10* at 6.4k rpm, when this happens (around 3.5k rpm) timing is at ~18*, tps @ ~75-80% in first, map reading is around 105-115kpa (can hear the turbo just getting going)

dville_gt

iTrader: (5)

The car hasn't been "tuned" but has been updated with a known good timing table from a very well known local tuner, and I have modified the VE table based on my previous N/A tune and interpolated my way into the higher map areas.

If it isn't an ignition problem then only other thing I can think of is that something is wrong with my injector data. They are resized FIC LS3 injectors (80lb @ 3 bar) and I had FIC provide me data for running them @ 3 bar vs. 4. Not sure if this could cause these issues or not however.

The only other tables that were modified from my N/A tune were some of the spark correction tables (IAT and ECT for boost timing protection), lowered the min spark advance to allow the PCM more control.

Thanks so far guys, I am going to try the plugs in the AM

So.jerZ-28

iTrader: (20)

Ive dealt with ngk plugs for years with my motorcycle shop. Ngks only have to get wet with fuel or foul out once and they are done...throw em out and start new. even though running the engine may clean the plug, they still may be partially fouled.
I would change to non projected 7's and bring gap to 22-25.

tomz28

iTrader: (20)

Im using autolites 3911 off the top of my head.

And bro you need to move pass the tuning for N/A tuning for boost is a new world. bite the bullet and find you some one in your area that tunes there own car. And start working together on your car.that help me allot when I started out.

pwrtrip75

iTrader: (8)

Why is everyone hung up on the plugs? Why not figure out WHY they fouled and address that? I'd get it leaned out and somewhat tuned in the ball park and then change them. Changing them now will just be repeating the process of fouling them.

AINT SKEERED

iTrader: (2)

Valve springs are not holding the valve closed under boost. A good friend of mine just went through the same issue. He bought the patriot extreme springs and shimmed them to 1.7850 install hieght and now has control of the valves under boost .

FlashLCD33

iTrader: (8)

^ Its pretty unlikely his springs aren't holding boost at 2psi. Stockers go well beyond that.