Car Lost ~50hp, Suggestions Welcome

[Swarzkopf1]

Went to the track last night looking for 12s. My best ET to date is 13.34 and my best MPH is 104.90. This time and MPH were obtained in ~75* weather in clear conditions, the exact same as last night.

So as to my runs....I gained.8 on my ET and lost 7mph. At this point, I have no idea why. My best run last night was the first one, with a 1.9 second 60', which felt strong, followed by a 14.1 second 1/4 mile at 98mph. WHAT THE ****. I didn't blow anything up, didn't overheat, don't hear any tell-tale noises from my block, and the car in general still accelerates and drives normally. Hell, it still feels as fast as it did when I ran 13.3@105, it just isn't. I made three runs, 14.1@98, then 14.2@96, then 14.4@96.

As I said, there are no tell tale signs. The car is running smoothly, not burning oil or coolant, not making any goofy noises, ect. According to the MustangWorks calculator, I'm down 50hp.

Here are the changes made to the car between last time at the track (13.3@105 and this time 14.1@9 :

160* Thermostat installed
New lightweight Summit seats installed, old seats yanked
Sound deadening and carpeting removed from interior

That's it...nothing I can see that would take away 50hp.

I tested my nitrous system this morning and it's spraying as it should. There is a slight leak where the injection nozzle meets the intake tube, but I don't think it's a 50hp leak.

Also, my coolant temperature sensor is ****ed and the cooling fan isn't working as it should, but, the car is NOT overheating and didn't overheat at the track. It ran cool as normal. Again, I don't think that this would take away 50 horsepower even if it were a factor (which it's not).

This weekend I'll check it over good, starting with the plugs, then the distributor, then the fuel pressure...at this point, I'm thinking one or two cylinders are not getting either fuel or spark.

Wish me luck. Any suggestions are welcome and appeciated.

[fiveohpatrol]

Were you using the nitrous then? If so, there could be a number of issues (low bottle temp, fuel and/or nitrous line or solenoid leak...)

Where is your nozzel mounted? It sounds like you could me letting in unmetered air through that leak. This means it will run leaner than normal, which can be bad, especially when using nitrous.

Get rid of that 160 thermostat, there is absolutely no need for it. Put a 180 in it.

How did you 60ft's compare to the previous runs?

Let us know how the plugs look, but I'd say they're going to be fine if you say it feels like it is running fine. If 1 or 2 cylinders were not firing, or were even slightly missing, you would know it. I've been there numerous times.

It would help to know a little more about the car. What year/tranny/engine combo, etc.

good luck

[Swarzkopf1]

Thanks for the feedback.

It's a 95 Mustang GT with an AODE. Stock motor with a Zex kit, 4.10s, drag radials, 190lph fuel pump, Aeromotive regulator, and other bolt-ons. As I said earlier, it went 13.343 a little over a month ago.

Were you using the nitrous then? If so, there could be a number of issues (low bottle temp, fuel and/or nitrous line or solenoid leak...)

I was using the nitrous. I tested the nitrous system this morning. The only leak was where the injection nozzle meets the intake tube. It's a very slight leak. I'll be solving this with some teflon tape. The bottle was at 1000PSI. It's a dry system that increases fuel pressure, so there is no fuel solenoid as in a conventional wet kit.

I don't believe this is a nitrous problem.

Where is your nozzel mounted? It sounds like you could me letting in unmetered air through that leak. This means it will run leaner than normal, which can be bad, especially when using nitrous.

Being that I was running 125 shot jets, had I gone lean my problems would probably be bigger than this.

Get rid of that 160 thermostat, there is absolutely no need for it. Put a 180 in it.

I'd always thought that the cooler the better. What would be better about a 180* T-stat?

How did you 60ft's compare to the previous runs?

About .2 slower. They were not traction limited, I run 275 series BFG drag radials. My previous best had been 1.8, yesterday my best was 2.0 with no tire spinning. I believe I just lacked the power to do any better.

[fiveohpatrol]

If your engine isn't up to operating temperature, your factory computer will run in "warm up" mode, which is going to run it rich. Now, I don't believe that is all of your problem, but it could be a little bit, especially because that's pretty much all you changed.

The nitrous kit seems suspect to me, even though you don't think so. You could have a plugged up line, or some other problem there. I'm not terribly familar with the Zex dry kit. How does it increase pressure? Does it just spike the fuel pressure regulator like the NOS dry kit does?

Have you noticed any difference in the naturally aspirated feel of the car?

I'm not an expert with the SN95's, but I do know that those computers are very picky. If it were me, I'd put a 180 or 190 stat in there and see what happens.

[Swarzkopf1]

The nitrous kit seems suspect to me, even though you don't think so. You could have a plugged up line, or some other problem there.

I tested the system by removing the intake tube, arming the system, and going WOT using the manual throttle.

The nitrous sprayed hard and fast for a good five seconds before I let off. If it's truly a nitrous problem, perhaps the nitrous I have is not pure enough....?

I'm not terribly familar with the Zex dry kit. How does it increase pressure? Does it just spike the fuel pressure regulator like the NOS dry kit does?

Yes, same type of vacuum connection.

Have you noticed any difference in the naturally aspirated feel of the car?

No, and that's what is killing me! The car feels exactly the same...idles the same, ect.

I'm not an expert with the SN95's, but I do know that those computers are very picky. If it were me, I'd put a 180 or 190 stat in there and see what happens.

Good point, the SN95 computer is known for being finnicky.

Thanks for the help. I'll be getting into it tommorow and I'll keep you posted.

[tarmon8r]

Originally Posted by Swarzkopf1

I tested the system by removing the intake tube, arming the system, and going WOT using the manual throttle.

The nitrous sprayed hard and fast for a good five seconds before I let off. If it's truly a nitrous problem, perhaps the nitrous I have is not pure enough....?



Yes, same type of vacuum connection.



No, and that's what is killing me! The car feels exactly the same...idles the same, ect.



Good point, the SN95 computer is known for being finnicky.

Thanks for the help. I'll be getting into it tommorow and I'll keep you posted.

Could be your torque converter especially if you are spraying it. More experienced racers might have a better insight but I have heard that converters going bad will slow you up, and if you are spraying it, the extra torque will shorten the life expectancy of a stock converter.