Help with a sick '95 Cobra

[95redSVT]

Ok, posted a little blurb on another thread about this problem and decided I would let veryone take a look/see and tell me what they think.

The car:
1995 Cobra, red, saddle cloth interior. 129,000 miles. Summit off-road H-pipes. twin Flowmaster mufflers. Venom 400 chip set. Koni adjustable shocks. Stock pretty much everything else.

The problem:
Took the car to a local place that I like and put my baby on the dyno. She dynoed at 143rwhp/160 tourqe. Put on the above mentioned H-pipes/muffler and venom 400. Got all of four (yes thats 4) more horses. So now im at 147rwhp/179 tourqe. Something isnt right with my baby I just dont know what. Nothing under the hood has changed except for the battery being in the trunk and the Venom 400. Whats eating up all my freakin power? I know the 95s got shafted some by the 96 GTs with the "new" 4.6 but jesus...I think I got a show model, not a street model. Any suggestions on what to check no matter how big, little, costly, stupid, crazy, idiotic are welcome.

P.S. If i had a scanner i would put a pic or two up, sorry guys. Just think of a red 95 cobra .

 

[984.6gt]

How does the car run, I would say bad plug ir two, but you would notice that, have you messed with the timing?

 

[Joes95GT]

Check the plugs. Are they blackish brownish and crudy? You could be running rich. I doubt you are running too lean. What is the fuel pressure set at? What is the timing set at? Is the car a stick or an automatic? The clutch or trans could be slipping. A lot could be wrong. Have you tried to pull codes? When is the last time the fuel pump or fuel filter has been changed?

Joe

 

[Rootus]

What have you done for maintenance? How does it run -- rough, choppy, or feels "normal"? What kind of gas mileage are you getting? Have you done a static compression test? Smoke of any color coming out the pipes?

I'd start with the easy stuff. Plugs, cap, rotor, wires, clean MAF, clean TB, replace O2 sensors. All of which is a good idea with the miles.

You're missing in the neighborhood of 70 horsepower...

Dave

 

[RIO5.0]

Yup...You got one sick Cobra there...I would think it runs terrible??? you make no mention of that...as mentioned above...I would pull the codes first...then do the tune-up if its been awhile...thing must be woofing gas???

 

[95redSVT]

Sorry, I should have mentioned all that. The car runs great. starts like a champ, has new plugs and wires. Doesnt burn oil. The timing is as i bought it but she seems to be fine. The only problem i had was battery problems since it was tiny and in the trunk. Solved that with an optima gelcell so thats out. The car is a stick so I can feel that the tranny is in ok shape. No grinding, so slipping, no stalling at low speeds. Idles fine. No smoke other then what normally comes from an exhust. Changed all the filters when i bought the car. Other then that...i dunno.

 

[Joes95GT]

Sorry, I should have mentioned all that. The car runs great. starts like a champ, has new plugs and wires. Doesnt burn oil. The timing is as i bought it but she seems to be fine. The only problem i had was battery problems since it was tiny and in the trunk. Solved that with an optima gelcell so thats out. The car is a stick so I can feel that the tranny is in ok shape. No grinding, so slipping, no stalling at low speeds. Idles fine. No smoke other then what normally comes from an exhust. Changed all the filters when i bought the car. Other then that...i dunno.

Fuel pump has seen better days...maybe? When you get on it, can you tell it doesn't have any power? Does it studder and buck when you do get on it?

Joe

 

[95redSVT]

doesnt stutter or buck. The guys at the dyno said it was the smoothest testing car that they had seen in a long time. No hills, no dips, no jerks, or anything like that on the dyno graph. HP went up smooth, toruqe started high and slopped gently down to meet the HP at 5200 RPMs. Im making a list of all this stuff on paper to check out when i get it to the farm shop. I have MAF, TB, Fuel pump so far.

 

[Joes95GT]

Check the fuel filter, and pull two plugs, one from each bank and see what color they are. This is a really bad test, but when you get on the car in first gear, does it throw you back into your seat? Do you get wheel spin on the 1-2 shift? If you do, in all seriousness, I would blame the dyno for low numbers.

Joe

 

[95redSVT]

1st when it hooks doesnt....throw me into my seat but there is a little pull. If i wanted I could chirp the tires in going to second but it would take some doing.

 

[Rootus]

Whether or not it chirps or spins on the 1-2 shift is very subjective, some people don't shift fast enough even when they try to make it happen. What kind of dyno was this test on? I'd get a second opinion, preferably on a dynojet (easier to compare numbers since most people use a dynojet).

Where was the torque peak, anyway (what RPM)? If it starts high & peaks at a low RPM, that could indicate an exhaust restriction of some kind, which would certainly kill your top-end power, and horsepower with it.

Also, you might find someone local you can informally "race", who has known horsepower. That would help tell you if the dyno was lying.

Dave

 

[95redSVT]

The RPMs peak at...2250 RPM I think but stay strong until around 4000 when they finally start to fall off. The exhust is....completely new. Nothing should even be on the inside of the pipes. Only gone about 100 miles on it. It was dynoed on a Mustang Dyno....and the next closest one is about 80 miles away. As for 2nd spinning I can shift it fast enough to do it but i have to keep the RPMs high and just drop the clutch. My roommate has an MX-6 that he is going to dyno (on the same dyno) soon so that will give me a chance to have someone here to match up against. I get the feeling i will lose since he can pull faster in 1st and 2nd (DAMN THE 3.08 REAR END!) but im pretty sure 3ed will take him since i can do 98 at the top end of third while he is shifting into 5th.

 

[Rootus]

2250 RPM

I'd expect the torque to peak at around 4000 to 4500, horsepower in the low 5000's. Wow.

Dave

 

[95redSVT]

Torque peaks at 2250*** sorry if anyone got confused at that.

HP/torque meet at 5200 RPMs at about 145. Torque maxes at about 2250 and stays above 170 till around 38-4000 RPMs then falls to meet that HP.

 

[sixty9boss302]

Wow dude i have read this whole thing and the only thing i can think of is that the clutch is slipping. I had that problem with my 91 gt and the RPM's would go up like normal but the car just wouldnt pull for $hit. How many miles are on the clutch thats in there now? If you have checked all the other things and it has been tuned up recently, the only other things i would check are the fuel pressure/pump and the filter. You should be pullin over 200 hp to the wheels, even on a mustang dyno. Check the clutch though. good luck man

 

[clarkjr]

Very well could be the clutch but you should smell the clutch burning after getting on it and on the dyno.

You need to check for codes first then go from there. This problem could be so many things but here is something else to check for. You mentioned the trunk mount batt... double check all connections, esp the ground. If the computer does not get the correct voltage, it will not function right (same with the ignition).

I had a '94 Cobra that dynoed at about 245 with just a Pro Chamber and CAI.

 

[95redSVT]

yeah, no burning of the clutch. My main guy who built the 10 second El Camino has drivin it around and he said the clutch was ok. I blew a clutch in a Volvo (as bad as that sounds) so Im pretty sure i know what that one feels/smells like. Where can i get the computer checked out?

 

[984.6gt]

I am gonna say bootleg dyno. Unless you just have the weakest 5.0 Mustang if all time.

 

[FordStang]

i agree with 984.6 GT

 

[haulbalz]

well, my cobra used to be slow as hell, changed alomost everything, it ended up being a bad mass air flow sensor, put the new one in and it was a screaming eagle. it's worth checking out..