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Mods in sig.

Before rt cat and borla exhaust I dyno'd at 150.3 whp and 136 ft/lbs with an intake and SCT reflash. Today I decided to go back to see what I put down with the new mods (car feels noticabley faster) and this is what I dyno'd at below. Could it be that I need new plugs?? 38,700 miles on my car with same plugs as I bought her with. The dyno I was on today was at a different place than the first place I went too. Today the dyno was a Dynojet 248H dynamometer. I know my car isnt' running right because a matrix xrx with intake and exhaust went right before me and put down 168whp. [:)][:)][:)][:)][:)]! Advice please!!!!
 

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Did you use the same dyno both times? I see you live in the bay area, you should have come to the dyno day we had last weekend.

Is it a Mustang dyno or Dynojet?

D'oh, I see the problem, I just looked at the dyno again, and they lost the tach signal above 6500RPM. This happened to a car at the dyno day, they couldn't get a good tach signal, so his horsepower when displayed by RPM was way off, but when they set it over speed, it was much more accurate. The choppiness in the lines is the tach signal to the dynamometer breaking up. As you can see, the curves are heading up, the horsepower curve is on track for well over 150, and then the lines start breaking up. I would recommend going back and asking for a refund or re-dyno.
 

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thefrush said:
Did you use the same dyno both times? I see you live in the bay area, you should have come to the dyno day we had last weekend.

Is it a Mustang dyno or Dynojet?

D'oh, I see the problem, I just looked at the dyno again, and they lost the tach signal above 6500RPM. This happened to a car at the dyno day, they couldn't get a good tach signal, so his horsepower when displayed by RPM was way off, but when they set it over speed, it was much more accurate. The choppiness in the lines is the tach signal to the dynamometer breaking up. As you can see, the curves are heading up, the horsepower curve is on track for well over 150, and then the lines start breaking up. I would recommend going back and asking for a refund or re-dyno.
Damnit, I knew something was off. Thanks for the advice bro. What would caust the tach signal to waiver like that? How can they get a better reading? Thanks for the advice.
 

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No, it is the tach signal, I've seen it before. Do you have aftermarket spark plug wires? One thing they do with a dynamometer is attach a clip to one of your spark plug wires, and that reads your tach signal for the dyno to know what RPM the car is at. Some aftermarket wires cause those clips to get bad readings. Other factors get involved too, but this is definitely what happened to you.
 

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Nope, same wires and plugs from the factory, but for racing 9mm wires and new plugs are on the way. thanks for the advice frush, I think you are dead on.
 

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That engine's vibrating like mad when you nail it - maybe the sensor just wiggled off a bit and you lost the signal.

But there is something other than that funky here - at 6250 looks like you lose the signal - but you are getting around 136 hp there. That's no good - if you're getting 150 hp peak or a little better with any of these tunes I'm familiar with, you should be seeing 145 at least at 6250.

My car pulls peak hp of around 152 at 6400 or 6500. I am seeing 150 at 6250.

It definitely lost signal, but there is something else going on. Hp and torque curves cross at 5250, like they should but...there is somthing funny going on - they are crossing at 125/125. You should be seeing like 135/135, or at least 133/133 where they cross, if you're going to be making 150+ peak hp.

You probably lost signal lower down than 6250, because your tq. peak of 136-137 at 3750 is pretty damn strong.

This looks like a "do over" for the dyno shop.
 

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Wow, with a Short ram, FC ORP and UDP I saw 156.4 on a Mustang Dyno....
 

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i so feel your pain bro
 

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Darth Focus said:
Wow, with a Short ram, FC ORP and UDP I saw 156.4 on a Mustang Dyno....
Obviously the dyno is inaccurate and is a basis for nothing. You shouldn't even compare to it.
 

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A dyno is only accurat for tunning, not true WHP or WTQ numbers, only estament. Esp saince you were on different dynos. A tuner can make a dyno read anything he wants. If he wants you to caom back, he can have it read lower then you expect, if he wants you satisfide, he can make it read higher. You have got to trust your tunner for more then a good tune, but accurate readings as well. So many parmaiters...
 

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HalfTime said:
A dyno is only accurat for tunning, not true WHP or WTQ numbers, only estament. Esp saince you were on different dynos. A tuner can make a dyno read anything he wants. If he wants you to caom back, he can have it read lower then you expect, if he wants you satisfide, he can make it read higher. You have got to trust your tunner for more then a good tune, but accurate readings as well. So many parmaiters...
That's why there are things like SAE correction. The problem here is not the dyno, it's not the tuner, and it's not the car, it's the simple fact that the tach signal was lost, and the dyno operator failed to notice it. Granted, he should have noticed it, when I saw it happen on a car, the operator saw it happening mid-run and stopped and re-hooked the wire.
 

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thefrush said:
That's why there are things like SAE correction...
Again, that's just an estament. An educated guess. I can make a dyno read out any numbers I want, and then show you the SAE and still be worth shit unless I did it correctly. Anyways, why turn this into a pissing match? Just trying to help out, and inform. Oh, it must be because I only have like 10 posts right? I must not know what the hell I'm talking about. btw, you should really go over to www.SVTPerformance.com, when you get help over thier, people don't try to turn it in to shit!
 

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I wasn't trying to turn anything into shit... I'm on SVTP and I know who you are. I'm not sure why you took offense at anything I said? Did I attack you? I certainly don't feel that I did.
 

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^ i don't think you said anything offensive or to attack him either. i don't see where "halftime" got that
 

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It's not you guys. Bad day on my end. No offence. My appoligies.
 

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No problem, hope it gets better. [thumb]
 
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