Heading to the dyno with my 03 Cobra... - Northern California Ford Owners

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Posted by Jeff S (Member # 371) on :

I'm on my way to go tune my 03 Cobra. My mods are K&N CAI, Bassani cat-back and a 3.10 pulley. Any guesses as to what it will make?

Posted by HaulinAssMaro (Member # 541) on :

301 [Whoo Whooooo!]

Posted by Glenn (Member # 520) on :

415

Posted by 1992gtdrop (Member # 4502) on :

435hp

Posted by TRIXSNK (Member # 2844) on :

420 [dance]

Posted by HungryHippo (Member # 537) on :

440/435

[ November 23, 2004, 02:32 PM: Message edited by: HungryHippo ]

Posted by Jeff S (Member # 371) on :

Well here are the results. This graph shows my previous stock-pulley/no-tune numbers overlaid with todays numbers using the 3.10 pulley and tune:

I'm not sure if i'm getting belt slip(my stock boost guage stays pegged) or spark blowout(plugs are gapped at .035) but something isn't quite right at 5700+rpms. I also thought i'd see more torque with this pulley.

My rear end is making all kinds of popping sounds so i'll be taking it to the dealership asap. Once fixed i'm gonna hit the dyno again with my 2.76 pulley and see what a difference that will make.

[ November 23, 2004, 05:16 PM: Message edited by: Jeff S ]

Posted by 2stangs69-91 (Member # 1951) on :

heck why take it a dyno 2 guy's guessed with in 1 to 5 hp [Eek!]

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by 2stangs69-91:
heck why take it a dyno 2 guy's guessed with in 1 to 5 hp

We have some good guessers on this board don't we. [Big Grin]

Posted by mtbaughs (Member # 4052) on :

Did you change the stock plugs to NGK TR-6's or autolite 103's? Your gaps fine. I've seen the stock ignition handle tons of boost so I doubt your blowing out the spark. If not you might want to try the plug change for the top end stumble your getting and see if that solves it for ya. Other than that are you running a larger idler pulley kit/shorter belt length? Belt slip isn't always seen on the boost gauge. Good numbers Jeff.

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by mtbaughs:
Did you change the stock plugs to NGK TR-6's or autolite 103's? Your gaps fine. I've seen the stock ignition handle tons of boost so I doubt your blowing out the spark. If not you might want to try the plug change for the top end stumble your getting and see if that solves it for ya. Other than that are you running a larger idler pulley kit/shorter belt length? Belt slip isn't always seen on the boost gauge. Good numbers Jeff.

Yes i'm running the TR-6's and a 100mm idler with 74.5" belt. I'm thinking it has to be belt slip at this point but not sure if I can fit a smaller belt on there. The 74.5 and 100mm idler seem to work for everyone else. [Confused]

Posted by BlueOvalRacing (Member # 1531) on :

You should put the stock pulley back on your car before you bring it in for rear end work. Trust me, Ford is getting pissy about modifications.

Posted by mtbaughs (Member # 4052) on :

quote:
Originally posted by BlueOvalRacing:
You should put the stock pulley back on your car before you bring it in for rear end work. Trust me, Ford is getting pissy about modifications.

EXACTLY

Also when you installed the pulley did you install it dry or did you use anti-seize or other lube on the shaft or pulley? If you did this can allow the pulley to spin on the shaft under boost. I've seen it happen many times from that.

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by mtbaughs:

quote:
Originally posted by BlueOvalRacing:
You should put the stock pulley back on your car before you bring it in for rear end work. Trust me, Ford is getting pissy about modifications.
EXACTLY

Also when you installed the pulley did you install it dry or did you use anti-seize or other lube on the shaft or pulley? If you did this can allow the pulley to spin on the shaft under boost. I've seen it happen many times from that.

Actually I did use anti-sieze butI thought about that while on the dyno so I made a line with whiteout and it wasn't spinning. I'm gonna change to some AR103 plugs and try to fit a smaller belt on it and see what happens.

Posted by BlackNGold (Member # 655) on :

It looks like you quite a bit leaner at 5700 compared to the previous pulley combo...Do you think it's a fuel problem?...

I wonder what is "popping" in the rearend too.... [Confused]

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by BlackNGold:
It looks like you quite a bit leaner at 5700 compared to the previous pulley combo...Do you think it's a fuel problem?...

I wonder what is "popping" in the rearend too....

The "red" run on the graph is the factory tune using the stock pulley which is too lean down low and too rich up top. My AF is perfect. [Confused]

[ November 25, 2004, 10:42 AM: Message edited by: Jeff S ]

Posted by TRIXSNK (Member # 2844) on :

Doesn't it seem as though what the problem could be is that if somethiing went in the rear-end on the dyno could that in theory ruin the continuity from driveline to wheels to dyno drum.....causing a strange almost loss of traction at the high end.

Has anyone a dyno graph of a car losing traction on a dyno? Does it look similar?

Either that or i would think belt slip.....do you see any belt dust in the engiine bay at all??

Posted by mtbaughs (Member # 4052) on :

Have you done this mod yet? http://www.rpmoutlet.com/boost%20bypassc.htm

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by mtbaughs:
Have you done this mod yet? http://www.rpmoutlet.com/boost%20bypassc.htm

Nope, but I have it disabled in my tune.

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by TRIXSNK:
Doesn't it seem as though what the problem could be is that if somethiing went in the rear-end on the dyno could that in theory ruin the continuity from driveline to wheels to dyno drum.....causing a strange almost loss of traction at the high end.

Has anyone a dyno graph of a car losing traction on a dyno? Does it look similar?

Either that or i would think belt slip.....do you see any belt dust in the engiine bay at all??

I sure hope so, I guess i'll find out in a week or so. I haven't noticed any belt dust, but i've only put maybe 20 miles on it and a few dyno pulls.

Posted by TRIXSNK (Member # 2844) on :

By the way what brand belt are you running?

I've heard bad about certain brands but have no personal experience as of yet.

Gatorback?

Posted by Jeff S (Member # 371) on :

Gates.

Posted by sharkattack (Member # 645) on :

Hey Jeff, thanks of the CAI. Saved me some time and cash. Bolted it on today and it is running like a champ [Eek!]

Hope you get your rear end problem worked out.

Posted by getjobdone (Member # 4666) on :

quote:
Originally posted by TRIXSNK:
Doesn't it seem as though what the problem could be is that if somethiing went in the rear-end on the dyno could that in theory ruin the continuity from driveline to wheels to dyno drum.....causing a strange almost loss of traction at the high end.

Has anyone a dyno graph of a car losing traction on a dyno? Does it look similar?

Either that or i would think belt slip.....do you see any belt dust in the engiine bay at all??

i have. the car isnt losing traction. if it were there would be a massive drop and then a little loop in the graph.

Posted by TRIXSNK (Member # 2844) on :

Any updates?

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by TRIXSNK:
Any updates?

The car is currently at the dealership for the rear end/suspension noise. If everything is ok/fixed i'll be heading to SAC this Saturday!

Posted by onesicklx (Member # 285) on :

quote:
Originally posted by Jeff S:

quote:
Originally posted by TRIXSNK:
Any updates?
The car is currently at the dealership for the rear end/suspension noise. If everything is ok/fixed i'll be heading to SAC this Saturday!

get ready to get smoked... [burnout]

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by onesicklx:

quote:
Originally posted by Jeff S:

quote:
Originally posted by TRIXSNK:
Any updates?
The car is currently at the dealership for the rear end/suspension noise. If everything is ok/fixed i'll be heading to SAC this Saturday!
get ready to get smoked...

Bring it!

Posted by Jeff S (Member # 371) on :

Got my car back from the dealer and it is 85% clunk-free. I think I still hear something every so often and they are going to do the 14mm bolt upgrade for me next week to hopefully get it 100% clunk-free it.

Posted by bunchmyfunky (Member # 360) on :

quote:
Originally posted by Jeff S:
Got my car back from the dealer and it is 85% clunk-free. I think I still hear something every so often and they are going to do the 14mm bolt upgrade for me next week to hopefully get it 100% clunk-free it.

Did they rebuild the rear? I have an 03 Cobra trac-loc and it made noises for a while after it was rebuilt, it took along time for the clutches to loosen up. Take it out and do a bunch of crazy eights and see if the noise goes away.

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by bunchmyfunky:

quote:
Originally posted by Jeff S:
Got my car back from the dealer and it is 85% clunk-free. I think I still hear something every so often and they are going to do the 14mm bolt upgrade for me next week to hopefully get it 100% clunk-free it.
Did they rebuild the rear? I have an 03 Cobra trac-loc and it made noises for a while after it was rebuilt, it took along time for the clutches to loosen up. Take it out and do a bunch of crazy eights and see if the noise goes away.

The just tightened up the nuts/bolts and readjusted the tailpipes. [Confused]

It is still cluncking a little but not nearly as bad.

Posted by Mario@APEX & Strictly-Motorsports (Member # 381) on :

We are tuning with SCT and also doing Gear installs. Our guy doing installs sets up gears for ProStock/Drag cars that are making 800HP+. We use FMS/FRPP gears and a top of the line install kit. We like to keep things in-house so that you know who you are dealing with. Our Gear guy has over 10+ years of installs.

Posted by Jeff S (Member # 371) on :

New numbers today with the changes being Autolight AR103 plugs, and a 2.76 pulley:

Posted by TRIXSNK (Member # 2844) on :

What type of pulley did you go with?

So do you think the problem was just belt slip then?

Anyway good #'s

[burnout]

Posted by Mario@APEX & Strictly-Motorsports (Member # 381) on :

Isn't 12.0:1 slighty lean for a blown car? I thought 11.5:1 was ideal?

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by Mario@APEX & Strictly-Motorsports:
Isn't 12.0:1 slighty lean for a blown car? I thought 11.5:1 was ideal?

On a pushrod motor 1.5 is usually ideal but the modular motors seem to like slightly leaner AF ratio's.

[ December 03, 2004, 10:00 PM: Message edited by: Jeff S ]

Posted by Jeff S (Member # 371) on :

quote:
Originally posted by TRIXSNK:
What type of pulley did you go with?

So do you think the problem was just belt slip then?

Anyway good #'s

Thanks! I'm running the billet-flow interchangable non-slip pulley setup. I'm not sure if it was the plugs, belt-slip or something else. My timing is conservative too with only 18* total.

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