Dyno Results - Have Questions

Treachery · Oct 15, 2005

I finally resolved a costly issue with my engine cutting out at high RPM. It turns out my spark plug gaps where to wide. Bringing the gap to .030" did the trick.

I brought my 93 GT in for a dynotuning and got

hp: 361.9@5500
torque: 369.9@4750

Not too bad but I was hoping for at least 420hp...

The tuner said the engine is not operating at full potential. The FMU must be disgarded and 42lb injectors be installed because my 30lb injectors were working at 90%. Additionally, he said that a MAF Extender is needed.

Aside from this, what else needs to be upgraded to achieve 420hp? Also, what is a MAF Extender and who makes it?

Engine Mods: TFS Stage II CNC Ported Heads; Stage II Cam; 1.6 Roller Rockers; Vortech SQ-Trim SC; Vortech Intake Manifold; 65mm TB; 75mm MAS; 30lbs Injectors; 190lph pump; Vortech T-Rex pump; MSD Dist; Crane Hi-6s

Thanks!

Daggar · Oct 15, 2005

A mass air extender is basically something along the lines of a resistor inline of the meter element. What your tuner is suggesting is that your meter is pegging before your motor is able to reach it's full potential. His suggested fix is to drop the signal voltage going to the computer so that you meter is able read more air volume prior to reaching its maximum output signal. He then plans to reprogram your MAF transfer function so the computer can make proper use of the new signals.

Anderson Motor Sports has one.

My question would be why?

Doesn't the EEC discard meter readings at WOT and revert to preprogramed fuel and spark tables at WOT? On a blower car, I don't see what good the extender would do unless you're pegging the meter at part throttle settings.

N8Miller · Oct 15, 2005

I know its hind sight, but you should have done the 42s to begin with. I feel that they would make a better match for your SC'ed car.

I never thought that gapping your plugs would make THAT much of a difference, but i guess it does.....

Michael Yount · Oct 15, 2005

Daggar - I don't think it disregards the maf signals at w.o.t. -- it disregards the O2 signals and goes into open loop at w.o.t.

pb_paulie_b · Oct 15, 2005

it does when the supercharger is blowing out the spark. you could possibly be running out of gas. did he monitor the air-fuel ratio?

Daggar · Oct 15, 2005

Michael Yount said:
Daggar - I don't think it disregards the maf signals at w.o.t. -- it disregards the O2 signals and goes into open loop at w.o.t.

Thanks Mike... I wasn't totally sure in that regard. His tuner's recommendation allot makes more sense then.

Treachery · Oct 17, 2005

I actually got the idea of the spark plug gap being too wide in this forum.

What hurts is that I needlessly replaced the ignition, distributor and FMU. I then had to pay an outrageous amount of $$$ for parts and labor... And the issue wasn't even fixed! In other words... I got shafted. Live and learn, i guess.

I have the 42lbs injectors on order. How much does a MAF extender cost?

Back to my original question in this post, what else can be done to get 420hp at the rear wheels, 400hp at the very least. Or, would the 42lb injectors, MAF extender and another tune be enough?

Lastly, during the dynotune, i noticed white smoke coming out from the sides of the engine at 4000rpm and up. I can only describe the smoke as having a chemical-like smell. Definitely not oil.

Thanks for helping.. And kudos to this forum! A great deal of what i know in regards to my Mustang came from this board.

VG30DE · Oct 17, 2005

If you get the 42's and a new MAF that's matched to the larger injectors, you no longer would need the MAF extender since the injectors have a wider operating range of flow and it wouldn't peg out the reading any more. Something is very wrong with your setup, because you should be getting almost that much power without the boost. Post up your air/fuel info if you have it, and what's your base timing set at??

Treachery said:
Lastly, during the dynotune, i noticed white smoke coming out from the sides of the engine at 4000rpm and up. I can only describe the smoke as having a chemical-like smell. Definitely not oil.

I dont wonna be the bearer of bad news.... but check your antifreeze

just4bob50 · Oct 17, 2005

I bought a 90mm lightning MAF, 42 inj., and a pigtail for the new meter all for 369$ on EBAY. the seller was ( emustangparts) All the parts were new in the original boxes still sealed with the shipping staples. Everthing works great and i check that guy's EBAY store regularly before i buy else where.

Treachery · Oct 17, 2005

The antifreeze is good. No signs of oil. ( I say this with a big, "WHEW")

I brought my car to a muffler shop to check for leaks. Driver side header is leaking from the gaskets and passenger side is leaking through the welds on the collector. I listened through the stethiscope and heard the hissing noise. This hurts. Now i need to get another set of JBA's- another $350. Damn!

Is good to hear that a MAF Extender is not needed with 42lb injectors. One less expense. My base timing is stock at 10 degrees. All appears to be bolted on correctly except for the headers. I'm thinking of ditching the 75mm Pro-M bullet and go to a 80mm MAF, instead.

When the headers are replaced, the injectors replaced with 42lbs and the MAF at 80mm, should this combo finally put me at least 420hp considering the horsepower already gained shown in my dynogragh? A blown 420hp+ 93Mustang GT sounds about right, doesn't it?

VG30DE · Oct 18, 2005

Wow, at 10 degrees you should be making tons of power with boost. Yes, with 42's and a big MAF that works right, you can definately make 420 at the wheels with your combo. And why the crap are you stopping at 5500 RPM.... rev the thing up!!

Daggar · Oct 18, 2005

VG30DE said:
If you get the 42's and a new MAF that's matched to the larger injectors, you no longer would need the MAF extender since the injectors have a wider operating range of flow and it wouldn't peg out the reading any more. Something is very wrong with your setup, because you should be getting almost that much power without the boost. Post up your air/fuel info if you have it, and what's your base timing set at??

I dont wonna be the bearer of bad news.... but check your antifreeze

Just wanted to point out that if you're having custom tunes done, that you need not get a meter specifically calibrated for 42s. You'll have better resolution out of a meter that's not been modified. In other words: Stick with the OEM calibration and make your transfer adjustments through the tune.

Treachery · Oct 19, 2005

The tuner said that the engine begins to break up at 5500rpm because the supporting parts can not handle it. He also mentioned that the engine has much more potential for power and the 30lbs injector and the maf is what's holding it back.

The header leak is not helping none and it's an unfortunate and unexpected set back. I'll be sticking with the JBA's but may get the Titanium coating depending on how much more they cost. If too much then the standard double nickel plating that i have now would do fine. It lasted 10 years and it's built like a tank.

KamiKaziDK · Oct 19, 2005

I vote for 70-75mm TB on top of the stuff already mentioned, esp since you have the blower

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