Just came back from the dyno

[bsmith9165]

I just got back from the dyno and my numbers were somewhat dissappointing After installing the KB Supercharger and dropping the compression etc..... I hit 379 hp/376 tor. I was hoping for 410 hp and 399 tor I guess that the only option I have left is to get a bigger TB. Any comment or suggestion would be greatly apperciated.

 

[LaserCobra 98]

Tell us a little more about the car.
What year?
How much boost?
What compression?
Other mods?

I rememeber KB's being poor performers on 96-98 Mustangs because of that restrictive inlet.

 

[HISSMAN]

Subscribing

 

[bsmith9165]

98 Cobra w 3:73 rear end

The mods I have are:

KB Supercharger 12 psi
Manley 18cc pistons comp is at 8.5/ 1
Full length header no cats
255 fuel pump
I know during the tune the tuner set the AF at about 11/1

 

[HISSMAN]

Was it a Mustang (loaded) dyno, or a dyno-jet?

 

[bsmith9165]

I think it was loaded because it has a 3000 lb drum that the car sit on. Dumb question on my part, what is the difference between them?

 

[LaserCobra 98]

I think it was loaded because it has a 3000 lb drum that the car sit on. Dumb question on my part, what is the difference between them?

Those numbers seem low even considering the dyno differences.

The word is Mustang dyno's usually give lower numbers compared to dyno-jet. Someone said you could tell by the drum- double drum: mustang dyno; single drum: dyno-jet.

Do you have a graph we can look at? Maybe the A/F readings?

 

[mmarfan]

11 to 1 fuel mix is rich! You should have him tune it closer to 13 to 1. You should achieve good results with that.

 

[HISSMAN]

11 to 1 fuel mix is rich! You should have him tune it closer to 13 to 1. You should achieve good results with that.

No, I would shoot for 12:1 with your compression. It might be worth ab=nother 10-15 ponies. Maybe a fuzz more.

 

[mmarfan]

No, I would shoot for 12:1 with your compression. It might be worth ab=nother 10-15 ponies. Maybe a fuzz more.

Not compression, air/fuel mixture. 13 to 1 is optimum

 

[HISSMAN]

Not compression, air/fuel mixture. 13 to 1 is optimum

Not for these cars. 13:1 A/F will be way to lean. If I ran 13:1 in my cobra I would have rods hanging out of my block from detonation. :nonono: noobs.

His 8.5:1 Compression is very close to what is in the 03/04 cobra, and that will allow him to run much more boost in the future, but the more air you pump, the more Fuel he will need. and 13:1 will kill these engines with 12lb of boost or more.

 

[LaserCobra 98]

11 to 1 fuel mix is rich! You should have him tune it closer to 13 to 1. You should achieve good results with that.

I don't agree. 11:1 is safe but 12:1 is ideal.
13:1 is dangerous.


Mine dips down to 11:1 from 4300 to 6000 and then leans out to 12:1. Yes I loose power, but I feel a lot safer.

But if I had his motor, I'd push 12:1 without worry.

Not for these cars. 13:1 A/F will be way to lean. If I ran 13:1 in my cobra I would have rods hanging out of my block from detonation. :nonono: noobs.

:lol:

 

[mmarfan]

[

Not for these cars. 13:1 A/F will be way to lean. If I ran 13:1 in my cobra I would have rods hanging out of my block from detonation. :nonono: noobs.

His 8.5:1 Compression is very close to what is in the 03/04 cobra, and that will allow him to run much more boost in the future, but the more air you pump, the more Fuel he will need. and 13:1 will kill these engines with 12lb of boost or more.

Easy there. I was under the inpression that a close to 13 to 1 was ideal. I've read it many places, but wasn't sure on the Cobra... Anything above 13 to 1 would be lean. I'm coming from the Contour SVT croud, sorry...

BTW not too new, look at member date ;-)

 

[HISSMAN]

[

Easy there. I was under the inpression that a close to 13 to 1 was ideal. I've read it many places, but wasn't sure on the Cobra... Anything above 13 to 1 would be lean. I'm coming from the Contour SVT croud, sorry...

BTW not too new, look at member date ;-)

No problem, and sorry for the noob remark. It was just starting to seem like no matter what I said you were going to counter. Thanks for your input though, and you can go away with the fact that you learned something new today. :beer:

 

[mmarfan]

No problem, and sorry for the noob remark. It was just starting to seem like no matter what I said you were going to counter. Thanks for your input though, and you can go away with the fact that you learned something new today. :beer:

:thumbsup: :rockon:

 

[bsmith9165]

I think it was a dyno jet because it had one drum. I think the next mod I will do will be a bigger TB and I will have him lean it up a bit. Thanks for the input if you have more please post.

 

[LaserCobra 98]

I was looking into KB when I had my 98 but started to re-think when I saw the numbers people were getting. From what I understand, KB had to develop a kit that would accommodate the stock hood. In order to do that, he restricted the inlet at the back of the blower. Not only did this cut airflow, but it also cut efficiency. Basically they would hit a brick wall around 400hp.
People started to complain and said they would switch to the 99/01 kit when it came out (which was YEARS later because of the 03 development) and slap a cowl hood on.

Anyways, that's what I recall and it might not be true anymore but it's something else to consider.

 

[HISSMAN]

I was looking into KB when I had my 98 but started to re-think when I saw the numbers people were getting. From what I understand, KB had to develop a kit that would accommodate the stock hood. In order to do that, he restricted the inlet at the back of the blower. Not only did this cut airflow, but it also cut efficiency. Basically they would hit a brick wall around 400hp.
People started to complain and said they would switch to the 99/01 kit when it came out (which was YEARS later because of the 03 development) and slap a cowl hood on.

Anyways, that's what I recall and it might not be true anymore but it's something else to consider.

That makes sense.

 

[cobra4v]

Your hp is way to low.. with 12 lbs of boost it should be well over 400 rwhp. Are you getting the full 12# of boost?. 11:1 is a very safe air fuel ratio. I would not go pass 12:1. You should be able to add more timing than normal with your built motor. Talk to your tuner. My 98 Cobra with a kb 8# on a stock motor dyno 360 rwhp with a conservative tune, air fuel was 11:1...I use Calif crappy 91 octane gas.

 

[Daves91coupe]

13:1 is perfect for n/a cars. 11:1 or 12:1 is perfect for boosted cars. I'd be leaning towards 11:1 with your combo.