98 Cobra Dyno Tuned - Finally!

[jfisher]

Had the opportunity to take the 98 Cobra down to Lee Blankenship in Shelbyville, KY for a dyno tune last week. It came down to the last minute as Lee is booked out months in advance and I had some weird issues with the car until I had some help discovering a big vacuum leak.

Car was able to muster 318whp and 325wtq WCF. It was interesting to see the hp peak at 6300rpm as I was thinking the stock 98 cams would peak a bit higher. The C heads really picked up on the top end over B heads as my tuner overlaid my graph with a graph of another 98 Cobra customer of his that had full bolt ons including LT's (I'm on Bassani Mids).

 

[Michael Plummer]

I'm assuming you are happy with the numbers, and if you are, then congrats to you. Drive that thing and enjoy it.

Good luck
Michael Plummer

 

[96blak54]

Lee Blankenship is a good dude. He goes the extra mile with tuning to ensure great drivability

 

[jfisher]

I'm assuming you are happy with the numbers, and if you are, then congrats to you. Drive that thing and enjoy it.

Good luck
Michael Plummer

I was expecting 300whp with the lower compression pistons, but secretly was hoping for 320whp so I am super happy with the results. The weather is finally looking better this weekend so hopefully get to enjoy it soon

 

[jfisher]

Lee Blankenship is a good dude. He goes the extra mile with tuning to ensure great drivability

That is exactly how I would describe him. I honestly think he spent as much time on drivability as he did with the car making power. I still have a funky idle issue with the car coming down from higher rpm, but I have a Standard Motor Products IAC on the car now and that could be causing some of the issues. I can't find a new OEM IAC anywhere.

 

[Musturd]

Nice numbers . Just in time for nice weather to enjoy it

 

[Michael Plummer]

I can't find a new OEM IAC anywhere.

Hi there,
IAC: Plays a very small role in idle quality. Its main function is to allow air into the engine without passing through the throttle body. So it's more a function of holding/controlling your idle speed and NOT idle quality.

NEW: https://www.ebay.com/itm/3255737194...NRx7FiKQnczFq1s7ITJ+s4/lR2|tkp:Bk9SR6TpuO3-YQ

I hope this helps
Michael Plummer

 

[jfisher]

Hi there,
IAC: Plays a very small role in idle quality. Its main function is to allow air into the engine without passing through the throttle body. So it's more a function of holding/controlling your idle speed and NOT idle quality.

NEW: https://www.ebay.com/itm/325573719493?epid=227678784&hash=item4bcdb4b5c5:g:eCIAAOSwQx9jTEat&amdata=enc:AQAIAAAA4F39pnSpyuRTqg9K8Fv25vPT2bTvrLDzAjDEs8394nLi7floaPG5+ga1x7Bkrf0JrU1rkfeAG65Yu+NMZxCExYv0nNKM0u+GBwFlNJDGxRpMebYyMmPWryki7ybqGF8dfrljOyIaJhPsusrfIJNrNWeCE0mVp54aqx5l2kFQHt/+54kY7W0MlZVCw9bwuFuopCqzQ/v+k6wQlC0G38fvbRioMiQ7YlECiDu6fhWDhOTCWQI6Lzbt6EEVHmGDsNYXiGwoQkXvaFm3yBMoJ0NRx7FiKQnczFq1s7ITJ+s4/lR2|tkp:Bk9SR6TpuO3-YQ

I hope this helps
Michael Plummer

That really sounds like my issue. My idle quality itself is fine when it's idling. The issue I have is the car wants to die if I'm hard on the brakes or if I throw it into neutral while slowing down.

My speedo is also WAY off with the 4.10's and I was reading where that could potentially be part of the issue as the car thinks it's moving at a different speed than it really is. I finally found a Dallas Mustang Speedcal and still need to get it installed.

 

[Michael Plummer]

That really sounds like my issue. My idle quality itself is fine when it's idling. The issue I have is the car wants to die if I'm hard on the brakes or if I throw it into neutral while slowing down.

I didn't tune your car, but your issue could be that your "Dashpot parameters" weren't set up. For example, Dashpot Ramp Target RPM: This value will be added to your Base Idle RPM in Neutral to create a point where the Dashpot Decay will slow down. From this point, the engine RPM will decrease at a slower rate to give the engine a chance to stabilize before dropping to the base idle speed. The fix is to go back to the tuner.

Incorrect speedo: I doubt this is your issue, but always fix what you know isn't right and move to the next item. Fixing your speedo is easier, do that first.

I hope that makes sense, and good luck
Michael Plummer

 

[jfisher]

I didn't tune your car, but your issue could be that your "Dashpot parameters" weren't set up. For example, Dashpot Ramp Target RPM: This value will be added to your Base Idle RPM in Neutral to create a point where the Dashpot Decay will slow down. From this point, the engine RPM will decrease at a slower rate to give the engine a chance to stabilize before dropping to the base idle speed. The fix is to go back to the tuner.

Incorrect speedo: I doubt this is your issue, but always fix what you know isn't right and move to the next item. Fixing your speedo is easier, do that first.

I hope that makes sense, and good luck
Michael Plummer

Appreciate the help! Good stuff. I was actually reading up on that today.

I will reach out to my tuner and ask. I do know that he tried to fix this issue for a solid 1.5 hrs and the car just wasn't reacting to the changes. I don't know for sure if my tuner was messing with the "dashpot parameters", but I will definitely ask. He did say he's run into this issue before and a couple cars just never reacted to any changes until the IAC was changed to an operable unit.

 

[joe65]

i like it. 318 whp is what close to 375 ish at the crank. good fun running street car. What gears are you running? My Mach 1 really wanted some 410s. The 355's were ok but i felt like the way it wanted to pull it just took too long to get to 4the gear.
- Just noticed your signature has the 410s in there. That thing must be fun to drive when you want to lay into it!

 

[jfisher]

i like it. 318 whp is what close to 375 ish at the crank. good fun running street car. What gears are you running? My Mach 1 really wanted some 410s. The 355's were ok but i felt like the way it wanted to pull it just took too long to get to 4the gear.
- Just noticed your signature has the 410s in there. That thing must be fun to drive when you want to lay into it!

Appreciate it. I have 4.10's. When I had the car dyno'd I had the stock T-45 in the car, but have since swapped in an 03 Cobra T-56 with the 2.66 first gear. I'm going to stick with the 4.10's for now as I'm going turbo this winter, but the car needs a bare minimum 4.56 gear with the T-56 if I was keeping the car in it's current NA form. With the 2.66 first it's like I went back to the stock 3.27 gearing.

 

[joe65]

Appreciate it. I have 4.10's. When I had the car dyno'd I had the stock T-45 in the car, but have since swapped in an 03 Cobra T-56 with the 2.66 first gear. I'm going to stick with the 4.10's for now as I'm going turbo this winter, but the car needs a bare minimum 4.56 gear with the T-56 if I was keeping the car in it's current NA form. With the 2.66 first it's like I went back to the stock 3.27 gearing.

When i first saw that you replied i was confused because this was a while back. Turbo this winter huh? Not sure you'll like that extra power. lol. Good project!