Whats wrong with my KB Cobra?

[not Jake]

Saturday night I was running a good friend of mine in his 2003 Cobra (Sonic Blue). His name is CODE BLUE on here and I'm sure he'll chime in.

Anywho, his Cobra has the following

2.76 / Bassani O/R X / Bassani Cat-Back / JLT CAI / Steeda FLSFC / Steeda 100mm / BBK 62mm TB / Drag Bags / H&R SS

Nitto 555R's on 18" authentic FR500's

Made 443/458

He shifts at 6,500



Mine has the following

2.6H KB @ 17# (3.5 upper, stock lower, 100mm BF idler)
JLT RAI
AccuFab Big Oval
UPR O/R X and MagnaFlow CB
BAP/60's/2600MAF
Nitto 555R's

I made 582/514

I shift at about 6,100 RPM's


Look at this slip, me vs. him on a 1,000' track. Looks like mine falls on its face between the 1/8 and the 1000' mark. Any ideas? Thanks guys.:beer:

I'm right lane.

 

[not Jake]

I'm sure it will be asked, so I'll answer here. No I have not datalogged the car yet. I might be able to in the next couple days though.

 

[96stanggt]

His times are about right for that 60', his mph is a little low as is yours. I'd honestly say it's a combo of you shifting so low and probably just shifting slow....

 

[01tahoe]

possibly experiencing some belt slip? who did the tune?

 

[timpryor]

I hate to be an ass but, how much seat time have you had at the TRACK?

 

[KONA BLUES]

Hello all.....I would like to elaborate for Jake a bit on this subject.

His times are about right for that 60', his mph is a little low as is yours. I'd honestly say it's a combo of you shifting so low and probably just shifting slow....

Slow shifting is not a factor here, I agree that he may be shifting a bit premature but definitely not slow.

As far as the numbers go, my 1/8th mile times and speed put me somewhere in the 11.80's @ 120ish MPH in the 1/4 and that is right in line with what most pullied cars are running. Neither Jake nor myself are doing 5 to 6,000RPM sidesteps, so are we seeing the absolute best ET/MPH, absolutely not, but they are ballpark numbers for the type of mods I currently have.

possibly experiencing some belt slip? who did the tune?

This is one area we believe he is definitely suffering from. but what is the cause is where we are searching. It could be a worn belt, but I believe it is something more than just a worn/loose belt.

BTW, the car was tuned by DynoSpeed Racing in Memphis.

I hate to be an ass but, how much seat time have you had at the TRACK?

Seat time is not an issue either, he has many passses in this car and can drive the car quite well. Something is not right and the numbers show this between the 660' and the 1000' mark.


Here is a link to some of the runs from this night of racing..........VIDEO LINK


I am wondering if many of you KB Terminator owners have experienced some of the same problems KB Lightning owners have. I recently swapped over from the L side and have seen many KB trucks that have had cracked or improperly adjusted boost actuators after swapping to the KB. Is this a known problem with the Terminator?

I believe that Jake is suffering from belt slip, but it seems as though the supercharger is loading up and causing the slip (I know that the more boost you make, the more parasitic drag it places on the motor/belt and the harder the engine must work to turn the S/C), but it seems that the blower is working against itself. This combo Jake is running is making 17lbs of boost. Jake noted that the S/C was extremely HOT to the touch the night of our runs (by this, I mean abnormally HOT). This was one of the consistent side effects of the malfuntioning boost actuator in the L community.

I know he needs to datalog, this was simply a stab in the dark by him to see if any of you guys have experienced any growing pains after swapping to the KB.

In looking at his slip, the most disturbing thing to me is this.......

He has me by 5MPH at the 1/8 mile mark and I believe it would be logical to assume that he should at the very least double that margin by the 1000' mark. However, I make up that 5MPH difference and end up with a higher trap speed by the 1000'. This simply should not happen in an EATON vs KB 2.6 race, all is not well with this particular KB Cobra.


Thanks for the input so far guys, maybe someone can chime in and give my bud a nudge in the right direction.

:beer:

DORF

 

[Hissssnsvt]

A buddy of mine is experiencing the same issues with his 2.8KB, we actually datalogged his runs with a Predator and his IAT2 temps were over 150* by the 1/8 mile. Joe@Dynospeed has a great rep for tuning some of the fastest Cobra's in the country. He also has a excellent rep for keeping them running safe. If I had to guess, he probably has your tune setup to pull alot of timing when your IAT2 temps get over a certain point. This could very well be the reason for your low MPH. This should be datalogged at the track or a back road where you can go full boost thru all 4 gears. A simple 4th gear pull on the dyno wont tell you whats really going on.

One other thing this could be besides belt slip is your clutch. What clutch are you running?

 

[Torched_03]

He is still on the stock clutch.

 

[not Jake]

Not so sure its the stock clutch anymore, Chy. We bought the car with 30K miles on it, it has 60K miles on it now. My wife learned to drive a stick on this car (its her DD) and I havn't ever smelled clutch or had reason to believe it was slipping (unless this problem is the clutch slipping ) Another reason to believe it is aftermarket is b/c of how stiff the clutch pedal is.

 

[03cobrarocks]

Not so sure its the stock clutch anymore, Chy. We bought the car with 30K miles on it, it has 60K miles on it now. My wife learned to drive a stick on this car (its her DD) and I havn't ever smelled clutch or had reason to believe it was slipping (unless this problem is the clutch slipping ) Another reason to believe it is aftermarket is b/c of how stiff the clutch pedal is.

The clutch on these cars stock is very very stiff for a stock clutch so it would not suprise me... although I dont know how a stock ford clutch could last that many miles...

I have a ram 900 in mine and it is maybe 1/2 the effort of the stock clutch...

 

[COBRA55]

Slow shifting is not a factor here, I agree that he may be shifting a bit premature but definitely not slow.

As far as the numbers go, my 1/8th mile times and speed put me somewhere in the 11.80's @ 120ish MPH in the 1/4 and that is right in line with what most pullied cars are running. Neither Jake nor myself are doing 5 to 6,000RPM sidesteps, so are we seeing the absolute best ET/MPH, absolutely not, but they are ballpark numbers for the type of mods I currently have.

On my car if I hit a 7.8's 1/8th that usually good for a 11.9-12.0 1/4 Mile..

If I run a 11.8 my 1/8th is usually 7.6x. But your car may be different, maybe the DA or whatever :shrug:

7.5x = 11.7x
7.4x= 11.6x

 

[not Jake]

Any other ideas guys? I've had the flu the past couple days so I havn't felt like data logging...

 

[KONA BLUES]

On my car if I hit a 7.8's 1/8th that usually good for a 11.9-12.0 1/4 Mile..

If I run a 11.8 my 1/8th is usually 7.6x. But your car may be different, maybe the DA or whatever :shrug:

7.5x = 11.7x
7.4x= 11.6x

That may be true brother, I have never made a 1/4 pass, we only have 1000 foot tracks here in Arkansas.....:cuss:.

I was simply using a formula I found on one of our local sites.......1000' Time/.835 and 1000' MPH/.912.

I was trying to give a ballpark number is all...:beer:

 

[not Jake]

Mike, I'm beginning to think its my shifting rpm and shifting into 4th before the 1,000'...

 

[96stanggt]

That's probably it dude, KB's pull much harder up top than Eaton's. I've pulled the best times in my car shifting between 6300-6500 there's no reason why you should be shifting around 6100...

 

[Rice Eatr]

The first thing I would check is the IC pump. Jump the (4) pin connector to see if it is working properly.

 

[Posi]

Mike, I'm beginning to think its my shifting rpm and shifting into 4th before the 1,000'...

This can't be it because your car should pull like a freight train in 4th. Whether you shift 3/500rpm's early or not. Have you called your tuner and told them?

 

[not Jake]

This can't be it because your car should pull like a freight train in 4th. Whether you shift 3/500rpm's early or not. Have you called your tuner and told them?

No I havn't. I would rather not, either.

After looking at other peoples low 11 second timeslips, mine seems to be dead on. We both figured I would be around 115mph at the 1000' mark, though.

I need to check my I/C pump, and then datalog.

Thanks posi and Rice.

 

[JWC]

You haven't over filled the KB with oil have you? My son did on mine and it built up very high internal pressure, caused major drag, and chewed up the green rubber spline inside it. How much boost are you actually pulling and does it fall off? I just asked because of the extreame heat you talked about. Good luck and keep us posted.

 

[jlauth]

A buddy of mine is experiencing the same issues with his 2.8KB, we actually datalogged his runs with a Predator and his IAT2 temps were over 150* by the 1/8 mile. Joe@Dynospeed has a great rep for tuning some of the fastest Cobra's in the country. He also has a excellent rep for keeping them running safe. If I had to guess, he probably has your tune setup to pull alot of timing when your IAT2 temps get over a certain point. This could very well be the reason for your low MPH. This should be datalogged at the track or a back road where you can go full boost thru all 4 gears. A simple 4th gear pull on the dyno wont tell you whats really going on.

One other thing this could be besides belt slip is your clutch. What clutch are you running?

I totally agree that your car may be yanking some timing. This is what happened to my car when I went to the track last summer. I would defiantly try and data log before you make any other changes.