Went to the Dyno today...

LarsD

Founding Member
Jul 2, 2002
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Texas
Put down 224 HP and 274 tq. Noticed a couple of problems, after 3K my AF went below 12.0, it was consistantly 11.5 or so. That, and gas starts to puke out the gas filler. I think it may have something to do with the fact that my return line to the tank is kinked. My #'s start to drop off after 5K, I'm assuming it's because of my tune, and that I still have the stock TB and EGR spacer on it. Overall I'm pretty happy since I haven't had it tuned yet and I'm still using the stock EEC settings. Will post the dyno shots in a bit.

L.D.
 
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This was the first run, the second was the same, except it was down about 2HP.

Dynorun%231.gif
 
What kind of exhaust are you running?
Gas puking out the filler is too much tank pressure. If the return is kinked it might lower the tank pressure, that is if it effects it. Something else is up.
 
proxses said:
What kind of exhaust are you running?
Gas puking out the filler is too much tank pressure. If the return is kinked it might lower the tank pressure, that is if it effects it. Something else is up.

The only thing I could figure is that the fuel can't drain back fast enough and it's causing the pressure to backfeed into the tank. It's only happens after I run it over 3K rpms, anything under that and it's cool. :shrug:
 
Something is definatly not right about those numbers, and something is really wrong with gas puking back out the tank. Don't hear about that too often.

Do you think maby the fuel pump hose that connects the actuall pump with the assemble has a leak and is squirting gas towards the filler neck? That is the only thing I could think of. When you find out what it is, post it, this should be interesting.
 
90mustangGT said:
Do you think maby the fuel pump hose that connects the actuall pump with the assemble has a leak and is squirting gas towards the filler neck?

Don't think so, the fuel is actually pooling under the neck behind the fuel door, the gas cap and everything is soaked in fuel.
 
Your numbers look alot like mine Lars except that my torque curve doesn't fall off as quickly above or below the peak - it's a bit flatter. My ratio was fat as well - you'll likely pick up another 10 or 15HP/torque if you can get that ratio up around 13 or so. I was limited by stock headers; I go back in Friday with headers installed, and we're gonna change the wot scalars with the chip so I can bump my a/f from 11.8 up to around 13-13.5; also gonna play with total timing a bit. I've only got it set for 30 degrees total, and we may pick up a few hp up around 32 or 34. And then I'm gonna leave it alone and enjoy it cause it's running so good; I'm very satisfied. Let us know how it progresses as you change things.

Oh, and I wouldn't worry too much about the absolute numbers - most of that is just a guy thing (mine's bigger than yours). Use the same dyno/operator under similar weather conditions to track your changes for gains; note what rpm peak torque and HP are occuring at; shape of the curve -- but comparing absolute numbers across different dynos under different conditions is like comparing apples and oranges. With your package, I'd have thought peak power might occur a bit higher in the range, but it's hard to say.
 
Michael Yount said:
Your numbers look alot like mine Lars except that my torque curve doesn't fall off as quickly above or below the peak - it's a bit flatter. My ratio was fat as well - you'll likely pick up another 10 or 15HP/torque if you can get that ratio up around 13 or so. I was limited by stock headers; I go back in Friday with headers installed, and we're gonna change the wot scalars with the chip so I can bump my a/f from 11.8 up to around 13-13.5; also gonna play with total timing a bit. I've only got it set for 30 degrees total, and we may pick up a few hp up around 32 or 34. And then I'm gonna leave it alone and enjoy it cause it's running so good; I'm very satisfied. Let us know how it progresses as you change things.

Oh, and I wouldn't worry too much about the absolute numbers - most of that is just a guy thing (mine's bigger than yours). Use the same dyno/operator under similar weather conditions to track your changes for gains; note what rpm peak torque and HP are occuring at; shape of the curve -- but comparing absolute numbers across different dynos under different conditions is like comparing apples and oranges. With your package, I'd have thought peak power might occur a bit higher in the range, but it's hard to say.

Yeah, I plan to use the same place. I'm gonna try and fix than kink in my return line. I'm also gonna drop my fuel pressure a bit. It's at 41psi right now, I'll try 38psi and see what it does. Unfortunately I can't spend anymore money for a few months, so I'm gonna have to just live with it. All that really counts is the track #'s though. :nice: