96 Cobra Dynoed today.....terrible numbers!!!!!

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 6, 2005

#1

• Jul 6, 2005

• #1

Well I went to the Dyno today and made a few runs and I am really disappointed with the numbers they are terrible. Its a '96 Cobra with Aluminum Flywheel, Aluminum Driveshaft, MAC O/R H-Pipe, 2 Chamber Flows, 4.10 gears. Best I got was 178.63rwhp @ 4700rpm and 226.38rwtq @ 3400rpm. My Air/Fuel Ratio is what i think is the problem......it goes off the charts below 10.0 from 2500 to 3500 then slowly goes up to about 11.7 @ 4700rpm and stays there. I know that is running really rich, but how do I go about fixing this? and about how much hp am i losing b/c of how rich its running? I was thinking id be gettin around 250rwhp maybe im wrong! but i think 178rwhp is to low Any Info. would be greatly appreciated

 

Red35th

Member

Apr 18, 2003

609

2

19

Houston, TX

Jul 6, 2005

#2

• Jul 6, 2005

• #2

First your a/f is messed up yes...but for your car to be putting those numbers to the ground you might want to do a compression test.

The peak RPM number is also troubling.

What do you run at a track? Also was it a mustang dyno, perhaps the load scaling was WAY off.

Either something in your engine is toast or the dyno was wrong. If you car feels good then go to another dyno.

Good luck with it.

 

DropTopPony

Noob Slayer

Founding Member

Aug 13, 2002

2,570

3

48

south jersey

Jul 6, 2005

#3

• Jul 6, 2005

• #3

thats npi gt territory! You should be @265 + rwhp. Go to another dyno and get a tune. If that doesn't do it then your in need of a rebuild. Are all your cylinders firing? Thats just too low for that car.

 

MyEarsHurt

New Member

May 21, 2004

918

0

0

Jul 6, 2005

#4

• Jul 6, 2005

• #4

I dont think the A/F would throw the numbers off that much. Hmmm, yeah, like droptop said, try another dyno just to see, but maybe your engine is FUBAR? How many miles are on it? How do you treat it? Are you the only owner?

 

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 6, 2005

#5

• Jul 6, 2005

• #5

Car feels fine....but i do notice it starts to really pull hard at about 3k, but anything lower it doesnt seem to pull much.....Best I have got at the track is a 9.6 (1/8th) that was with traction problems. It has 63k miles on it. Im not the only owner jus bought it bout 4 or 5 months ago from a local dealership, but im pretty sure im the 2nd owner no clue how he drove the car was completely stock when i bought it. I do run the car hard honestly. Another thing i see some people are sayin to do the pulls in 4th gear, I'm almost positive the guy did mine in 4th could this be givin me the low numbers. Also, It was a dynojet!!!!

 

COBRA90GT

Mustang Master

Sep 22, 2001

6,654

0

87

HOCKEYTOWN ® , MI

Jul 7, 2005

#6

• Jul 7, 2005

• #6

A dyno pull in 4th gear is proper procedure. 1:1 ratio is achieved with the trans in 4th.


FYI - You *should* be upwards of the 260rwhp mark (SAE figure), given your mods. 96-98 snakes came with 305 flywheel factory ponies, which gave them a rear wheel horsepower rating of approximately 259 (SAE). 305hp x 85% = 259.25 rwhp (using the "standard" 15% drivetrain loss figure).


Are you 100% positive it was on a dynojet? Was it a portable dyno? Was the car properly fastened down on the dyno rollers? Was there sufficient airflow (large fan) for the car while it was actually on the dyno?

It sure sounded like it was on a Mustang dynometer judging by those numbers, but even that would be pretty low. Were those numbers STD or SAE and what was the correction factor? What were the weather conditions (temp/humidity)?


At a minimum, check/replace the sparkplugs. Is the air filter clean? Are the IMRCs functioning ok (it's probably a good idea to clean the intake out anyways). What kind of wheels and tires (much heavier aftermarket wheels)?

Just shooting a bunch of ideas at ya...

 

d98gt

Founding Member

Mar 14, 2002

4,505

59

204

SE Texas

Jul 7, 2005

#7

• Jul 7, 2005

• #7

That's even worse than a npi 96-98 gt.

Something isn't right about those numbers. Is it a popular dyno shop with experience?

 

M

Mel96GT

New Member

Aug 31, 2004

255

1

0

San Diego

Jul 7, 2005

#8

• Jul 7, 2005

• #8

Are you sure you don't own a Fobra??

 

topless98gt

Adhesive Feces

Mar 31, 2005

182

0

17

Arlington, TX

Jul 7, 2005

#9

• Jul 7, 2005

• #9

Dang, my 200,000+ mile 98 GT Vert put down 196rwhp NEARLY STOCK! Are you sure that thing is a Cobra?

 

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 7, 2005

#10

• Jul 7, 2005

• #10

Yes, Im positive it is a Cobra! Got all the SVT papers with it. It is a Mystic Cobra.

Thats what I thought I was suppose to be at was around 260rwhp, maybe a bit higher with the mods. I am 100% positive it is a dynojet, says it on the top of my sheet. It was not a portable dyno, was a shop that has just opened up in the past couple months. The car was fastened down of course, but I have no clue it if was done properly this is the first time I have ever even seen a dyno so Im new to all this. They had a fan sitting in front of my car, was not a really big one though.

What do you mean by the IMRCs?

And I still have the factory wheels with 245/45/17 Kumho tires.

I will post a pic of my sheet so you can see the figures.
but at the bottom incase you cant read it says:
"Run Type: RO Run Conditions: 81.58F, 29.04in-Hg, Humidity 56%, SAE: 1.04"

 

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 7, 2005

#11

• Jul 7, 2005

• #11

 

mogs01gt

Founding Member

Jul 22, 2002

3,113

30

119

Ohio

Jul 7, 2005

#12

• Jul 7, 2005

• #12

that is one messed up looking dyno sheet.

 

5

5spdBlack

New Member

May 25, 2005

44

0

0

NJ

Jul 7, 2005

#13

• Jul 7, 2005

• #13

mogs01gt said:

that is one messed up looking dyno sheet.

Click to expand...

agreed

 

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 7, 2005

#14

• Jul 7, 2005

• #14

Ya dont gotta tell me its a messed up dyno sheet. I just cant figure out what the hell went wrong with the dyno or if its something to do with my motor..........Motor feels fine though

 

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 7, 2005

#15

• Jul 7, 2005

• #15

Here is the Sheet that shows my Hp and Tq!!!! Yes, this one is messed up lookin too!!!!!!!

 

mogs01gt

Founding Member

Jul 22, 2002

3,113

30

119

Ohio

Jul 7, 2005

#16

• Jul 7, 2005

• #16

I think they put the load wrong into the computers.

How fast is your car?and yes I mean what have you hanged with on the street?

 

mrvax

Stay thirsty my friends

Founding Member

Nov 29, 1999

5,225

3

79

SN Moderator: Orlando, Fl.

Jul 7, 2005

#17

• Jul 7, 2005

• #17

If the car pulls pretty hard then that dyno is totally AFU. Best a/f ratio for N/A 4.6L engines seems to be about 13:1 across the board.

 

S

Saleen03Cobra96

New Member

Apr 4, 2005

32

0

0

Jul 7, 2005

#18

• Jul 7, 2005

• #18

I never seen the guy do anything with load on the computer. He seemed to be kinda lost when he started to use the computer, so maybe he never even had the load right at all? Could that be the problem?
As far as how fast my car is, It pulls hard at 3k and up, but anything lower seems to not pull as hard. Best run on a 1/8th track was 9.6 (That was just H-Pipe and Mufflers) Now with the 4.10s I cant hook up at all, need to get some drag radials! I dont really do much of the street racin, but a friend of mine has a camaro with a LS1 we were goin about 30mph and we both hit in 2nd gear. I stayed with him until we both shifted to 3rd then he was gone. That was done when my car was all stock btw!

 

BLK_ROUSH

Founding Member

Feb 5, 2000

1,300

0

36

Newnan, GA

Jul 7, 2005

#19

• Jul 7, 2005

• #19

Hoping it's operator error .. otherwise there are a list of things you should do.

1. compression/leak down test
2. check/replace sparkplugs
3. clean air filter

Is it throwing any codes? It seems so low on power ... something is really wrong.

 

mrvax

Stay thirsty my friends

Founding Member

Nov 29, 1999

5,225

3

79

SN Moderator: Orlando, Fl.

Jul 7, 2005

#20

• Jul 7, 2005

• #20

You know, 9.6 in the 1/8 equates to about 14.98 in the 1/4. What was your 60' time? I believe the 4v 4.6L doesn't really start to go until over 3K rpms so that's not unusual.

Again, if the car is running/pulling well, I'd take those dyno numbers with a grain of salt.