Supercharged Problem

nightrider50 · May 1, 2005

I Finally got my ride back yesterday from the shop. it got a vortech s trim. but it is still running the stock mass air meter. The tuner told me not to rev it over 4800-5000 rpms cuz it runs way too lean above that due to the stock MAF. So i just took it out to race a guy and i was shiftin through the gears really fast around 4800. when i went from 3rd to 4th a huge cloud of smoke flew up behind me and came all through my vents. the whole interior was smoked out. then the car backfired, not too loud, and shut off! we raced again about 5 minutes later and it did the same thing. any ideas what is going on?

Daggar · May 1, 2005

Sounds like your meter 'might' be pegged.

The reason I say 'might' is because there are several things that cause the symptoms you describe. A lot more information is required to try an pinpoint the problem.

Injector Size
FMU
Fuel Pressure
Air Fuel Ratio
Spark plug type and gap
Cam
Compression Ratio
Amount of Boost
on and on....

If what I gather from your post is correct, then the shop you took it to, to get the blower installed is made up of a bunch of F'n morons.

You've got a couple of options here... The first is to tune it yourself. It doesn't sound like you have the equipment or know-how to do that so may want to opt for option two and find a tuner that knows what the hell they're doing to get your combination under control before you end up causing real damage to your motor.

Good Luck!

nightrider50 · May 1, 2005

30# injectors
MSD FMU (came with vortech kit from summit)
14:1 Fuel Pressure
i think .035 gap on plugs?
Trick flow stage one cam
9.5:1 compression before supercharger
8psi

hllon4whls · May 1, 2005

nightrider50 said:
30# injectors
MSD FMU (came with vortech kit from summit)
14:1 Fuel Pressure
i think .035 gap on plugs?
Trick flow stage one cam
9.5:1 compression before supercharger
8psi

14:1 is your air fuel ratio. Can you hold that A/F ration all the way to 5500?
I am sure this is a typo. Just want to help dagger to help you.

nightrider50 · May 1, 2005

No, the tuner shut it off at 4800-5000 because it gets too lean up above those rpm's. he said it is because of the stock mass air meter.

bgjohnson · May 1, 2005

i think he means a 14:1 FMU

Daggar · May 1, 2005

If it's the AFR that's 14:1 then that's too lean. If the FMu is 14:1 then that's way too much for 30# injectors.

I tend to think that bg is correct about the 14:1 being the ratio of the fuel disk in the FMU. If that's the case then that backfire you're getting is not from a lean condition but just the opposite. The fuel pressure is being ramped up too quickly and too much and giving you exhaust tube ingnition as a result. I take it that the FMU came with the Vortec kit? The kit was most likely designed for stock fuel injectors (19lb-ers).

BLOWN 5.0 FOX · May 1, 2005

I dont mean to steal the post-but I figure its better than to double post-I SEARCHED!

I am in a similar boat, I am about to get ready to tune my setup. The only real "tools" I have to work with is: Timing light, A/F Ratio Gauge (yea yea light show but better than nothing) and a fuel pressure gauge. My setup is in my sig however I will break it down to the major tuning components to help sort it out.

Powerdyne BD-10 SC - 6 psi pulley ( FMU Cal at 24# , Vortech BPV)
BBK Adustable FPR
Trick Flow street heat U/L
C&L 73mm MAF - cal at 24# sampling tube
FMS 24# injectors
BBK 70mm TB
MSD 6BTM IGN
Walbro 255 LPH FP
Stock heads /HO Cam (for now) (anything else check sig)

My question is in the form of a request for advice on how to begin tuning rather than to just set the timing and be done. I want to eventually bring it to a shop and get it tuned, however I just want to be in the ballpark to at least drive it to the body shop for paint without worrying about leaning out the motor.
What is the best tool for custom tuning (AF Ratio etc) - Tweecer? WB 02? other?
Also Should I first tune the motor with the SC belt off ? ( Removed Dizzy for intake swap and also installed the BBK Adjustable FPR. Car has been hibernating all winter).
Any advice from an experienced 5.0 tuner would be apreciated.

THANKS GUYS

Daggar · May 1, 2005

REQUIRED tools for tuning any SC combo:

Wide Ban Air/Fuel Ratio meter
In-car Fuel Pressure Guage
In Car Vac/Boost guage

If you're planning to tune it yourself you must at least know what the vitals are. Even if you're having the car dyno-tuned, I consider those things to be essential. If there's ever a problem, you'll not be able to track the problem without information from those guages.

A TwEECer or PMS would be ideal! In the case of having an ample sized mass air meter properly calibrated for adequate sized fuel injectors, I'd go with a PMS. They're realtively easy to learn and use. For any other scenario, I'd use a TwEECer, mechanical tuning, or a combination of the two.

A small tip for those that are using FMU's or are attempting to tune their combinations machanically instead of electronically. First off you MUST have an WB02 so that you can ensure that the FMU is the proper ratio for the amount of boost you're running and the size of the injectors that you're using. An FMU that puts you just a hair on the rich side is ideal. Go to the fish store (yes, fish) and get a large brass, variable, shutoff valve. You can use th valve to change the rate of the vaccum going to the FMU and slow the rate that the FMU ramps pressure up as you get into the boost. It's can be a painstaking process but can be made consdierably easier if you have a wide band that's capable of data-logging the AFR along side of the RPM.

The ideal tune (of course) would be to have injectors large enough to handle the power you're trying to put down and custom tune of some sort (either by custom chip or EEC tuner).

bluevenom867 · May 1, 2005

A EGT gauge is a good idea too...

BLOWN 5.0 FOX · May 1, 2005

I have an autometer Boost/Vac gauge on the a-pillar ... and a liquid filled fuel gauge mounted under the hood with the shraedar valve on the fuel line. I plan on tuning with a buddy so this should not be a problem...

What have you heard about ...PLX Devices M-300 Wide Band Oxygen Sensor Kit? It appears to be self-contained and has its own digital read out. See Link Below.

http://cgi.ebay.com/ebaymotors/ws/e...tem=7961938154&category=33557&sspagename=WD1V

Is this my missing link that is a MUST HAVE in order to safely and properly self-tune my stang? Or is there a better bang for my buck out there?

Thanks again guys

ALMOSTFINISHED · May 2, 2005

I am by no means a s/c pro but he stated in the original post that he had larger injectors and a stock maf. Isn't the stock maf only calibrated for 19 pounders? Maybe it is giving the eec the wrong info? Just a thought.

Nick

ALMOSTFINISHED · May 2, 2005

I am by no means a s/c pro but he stated in the original post that he had larger injectors and a stock maf. Isn't the stock maf only calibrated for 19 pounders? Maybe it is giving the eec the wrong info, like things are not calibrated for each other? Unless the FMU is taking care of that...but I always thought that the FMU was to make the injectors act like larger ones? Just a thought.

Nick

Daggar · May 2, 2005

BLOWN 5.0 FOX said:
I have an autometer Boost/Vac gauge on the a-pillar ... and a liquid filled fuel gauge mounted under the hood with the shraedar valve on the fuel line. I plan on tuning with a buddy so this should not be a problem...

Thanks again guys

Ahhhh... so your buddy plans to ride under the hood as you do power runs down the street, calling out fuel pressures across the power range? I don't have friends like that. lol

You can't tune your SC by sitting in the driveway (unless you have a dyno in your driveway). I've never really understood the logic behind a fuel guage permanently mounted in the engine bay. No body rides up that and there's a considerable amount of pressure variation as the motor goes through the power range. I don't recommend mounting the AFR meter in the engine compartment either (although some are backlit).

The PLX is a nice meter. If I remember right, it requires a laptop to do data-logging. If you've got one, you're in business. If not, you may want to consider an innovative LM-1 with the RPM converter. The data logging is self contained and you can remove it from the car, take it inside, and download it to your desktop computer. Having the RPM function is a huge advatage as well. It's allot easier to know where in the data log you are when you can look at the RPM and know if you're accelerating, decelerating, or just cruising, etc...

Stang8URMPRT · May 2, 2005

I agree. Your problem is probably from the stock MAF is not calibrated for your 30 lbs injectors. That'll cause major problems. lol

Daggar · May 2, 2005

ALMOSTFINISHED said:
I am by no means a s/c pro but he stated in the original post that he had larger injectors and a stock maf. Isn't the stock maf only calibrated for 19 pounders? Maybe it is giving the eec the wrong info, like things are not calibrated for each other? Unless the FMU is taking care of that...but I always thought that the FMU was to make the injectors act like larger ones? Just a thought.

Nick

You are correct about the stock meter. I assumed that he'd already gotten that corrected. I mean... everyone understands this, don't they?. I also assumed that the hack shop that installed the blower for him would have at least known that much. You're right though... we should not overlook the obvious things that we don't have specific answers to.

Venom351R · May 2, 2005

I was running an FMU w/ a 8:1 disc w/ #30 injectors and it was way to rich. Since then the FMU has been taken out and just running off the #30's and its still acting as though it is running rich, I have no dyno A/F Ratio #'s to confirm this but Im sure I am way within the safe zone.

Venom351R · May 2, 2005

BLOWN 5.0 FOX said:
http://cgi.ebay.com/ebaymotors/ws/e...tem=7961938154&category=33557&sspagename=WD1V

Is this my missing link that is a MUST HAVE in order to safely and properly self-tune my stang? Or is there a better bang for my buck out there?

Thanks again guys

To self tune it yes, or you can just go to the dyno and see where your A/F raito is at from there.

BLOWN 5.0 FOX · May 2, 2005

Daggar said:
Ahhhh... so your buddy plans to ride under the hood as you do power runs down the street, calling out fuel pressures across the power range? I don't have friends like that. lol

You can't tune your SC by sitting in the driveway (unless you have a dyno in your driveway). I've never really understood the logic behind a fuel guage permanently mounted in the engine bay. No body rides up that and there's a considerable amount of pressure variation as the motor goes through the power range. I don't recommend mounting the AFR meter in the engine compartment either (although some are backlit).

The PLX is a nice meter. If I remember right, it requires a laptop to do data-logging. If you've got one, you're in business. If not, you may want to consider an innovative LM-1 with the RPM converter. The data logging is self contained and you can remove it from the car, take it inside, and download it to your desktop computer. Having the RPM function is a huge advatage as well. It's allot easier to know where in the data log you are when you can look at the RPM and know if you're accelerating, decelerating, or just cruising, etc...

Well sorry, I dont mean to be ignorant- But I only installed that gauge to get a baseline to go by @ idle. I assumed the tuning involved more monitoring the air/fuel ratio at a broad range of RPMS, rather than fuel pressure.
If you cant tell by now, im a noobie to forced induction tuning, I wanted to post in order to get a better idea of what I am looking at for the tuning aspect as the entire unit is now installed.

I think I am going with the PLX M-300 , should I upgrade to the data logging feature??? I dont want to spend too much money on the tuning- and I dont want to cut any corners...so I need to find a mesh point.
More and more I am wondering if I should just drop her off at the tuner and be done with it, but I want to make a valid effort before I reach that point since up until this point I have done all the work myself.

Any idea on costs as far as getting vehicle properly tuned- and any area in New England that does this? Thanks again

dcarlson · May 2, 2005

Thre is no reason you can't get that thing running good with the stock computer, but you definately need more information to tune this car right.

You said the tuner "shut it off" at 4800 rpm. Do you mean he shut it off on the dyno or he set the rev limiter on the MSD? If you hit the MSD rev limiter, thats your backfire right there.

A lot of your info is unclear. You said "MSD FMU." MSD makes the ignition boost timing control. Not the FMU. The standard FMU disc is 12:1. A/F ration might have been 14:1. Either way you've got to recalibrate the FMU to match the injectors, probably with a 6:1.

Questions that need to be answered before you can go any further:
1) What is the calibration on the stock meter? Is it stock calibration or just a stock housing?
2) What fuel pumps(s) are you running.
3) Are you sure they are 30 lb injectors?
4) What is the base timing set at?

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