Mystic one the dyno, C head swap. RESULTS!

[NC Mystic]

1999 C head- runners ported and polished, valve seats relieved and valve id's opened up, combustion chambers cleaned up, B cams and spring

C lower intake with B upper intake via adapter plate

Stock 100k mile rotating assembly, one cylinder tests about 20lbs lower than the others which are high 180s but it is what is is and rebuilding the bottom end wasnt fiscally possible for me

March performance pullies, sean hyland water pump, long tube headers, offroad H , flowmaster 10 mufflers, mgw shifter, adjustable clutch/ quadrant etc, new timing chain, sprockets, tensionors (04 cobra style), and guides, ford racing 9mm wires, new copper plugs, new sensors, stock fuel rails and return system, stock coils, stock 3.27 gear, stock borgue warner t45, stock everything else but some gauges

the phone audio does it no justice, it sounds like a frantic T-Rex in person

Nc mystic dyno - YouTube

 

[NC Mystic]

Big thanks to N/A SVT and USMC Chief and everyone else that has helped along the way

 

[00_silvergt]

Good job. I was going to do a c head swap. Got ready to pull the motor. Gave up put it back to stock. Then got a good deal on a kb supercharger. And thats where am at right now. Although I still think about the c head swap haha

 

[na svt]

You're very welcome.

That dyno sheet looks odd as hell and cuts off well before the engine makes peak power or reaches it's "redline". If allowed to go to 6300 the power would have increased another 15-20...or more.

Why is that?
What type of dyno?
What correction factor?

 

[Tabres]

You're very welcome.

That dyno sheet looks odd as hell and cuts off well before the engine makes peak power or reaches it's "redline". If allowed to go to 6300 the power would have increased another 15-20...or more.

Why is that?
What type of dyno?
What correction factor?

I was going to ask the same thing. Thought the numbers were way low until I noticed what RPM they stopped the pull at...

 

[AZSN95SNAKE]

^ I'm wondering the same thing. I saw the numbers and was disappointed lol, then I saw the RPMs on the graph.

 

[NC Mystic]

I asked the same thing after the first pull, he said that the dyno sheet rpm was calculated by the wheel height and the dyno but the was pulling to 6900rpm on the aeroforce digital gauge in the car

 

[na svt]

well your engine sure as heck wasn't making peak power at 6900. The graph does not look like one from a C headed, cobra cammed car.

 

[NC Mystic]

it's got a 96 B came, did you watch the video?

From the drivers seat the graph makes sense, very smooth power gain that pulls hard all the way to redline. torque rolls on early and hard

i did notice the fuel cuts at 6600-6800? havent driven it in years so i couldtnt remember if it went to 7k before the build or not

on a side note it's really nice to be back in the cobra, makes the fox coupe i had feel like a tin can. sounds like a real door when you close it and it's nice cruising down the highway at 55-80. very pleased

 

[Mystic-SVT]

it's got a 96 B came, did you watch the video?

From the drivers seat the graph makes sense, very smooth power gain that pulls hard all the way to redline. torque rolls on early and hard

i did notice the fuel cuts at 6600-6800? havent driven it in years so i couldtnt remember if it went to 7k before the build or not

on a side note it's really nice to be back in the cobra, makes the fox coupe i had feel like a tin can. sounds like a real door when you close it and it's nice cruising down the highway at 55-80. very pleased

Fuel shut off should not be that low in the rpm's, I believe the shutoff is at 7200rpm for 96-98 cobras.

 

[NC Mystic]

its on the stock computer, what would be causing it to cut fuel early?

the knock sensor were deleted

 

[NC Mystic]

went for a night drive, nice cool air around 45-50f. cut fuel in 2nd gear just after 6k and at 6500-6600rpm in 3rd.

it has a stock computer and 90mm lightning maf, forgot to list that

 

[svtcobralover]

Post a few pics of the engine bay. I'm curious to see the C-heads with the B-upper.

 

[98BABCobra]

post a few pics of the engine bay. I'm curious to see the c-heads with the b-upper.

this!!!

 

[na svt]

Is the fuel being told to cut off or is it running out of fuel? How old is the fuel filter?

Do you have an xcal? If so, is your tuned unlocked so you can make changes?

 

[Mystic-SVT]

Post a few pics of the engine bay. I'm curious to see the C-heads with the B-upper.

this!!!

Looks just like a B headed motor guys...scroll down to post #125
http://www.svtperformance.com/forums/sn95-cobras-24/864000-b-upper-c-lower-adapter-finally-5.html

 

[NC Mystic]

it has a new fuel filter, and the stock computer on the stock tune with a 90mm lightning maf.

i will post pics but it looks just like a stock 96 engine bay and you can see the edge of the adapter plate between the intakes. stock coil packs and valve covers.

 

[NC Mystic]

Based on a gps phone app and the aeroforce interceptor in the car it's running high 12's-low 13's at 100mph, says im running 90mph in the 1/8th mile. give or take 5 with a 0-60mph time of 4.6-4.8 seconds

Given, the street offers more traction but that's where the car lives so it's cool to get some "street times". I'll certainly take it to the strip when they open back up.

I know that's not the fastest car in the world, street or track but im really excited about that personally. That's pretty much the out of the box times of all my childhood big block heroes (427 cobra, 68 gt500kr, boss 429) and to get that out of a n/a 281ci with a 3.27 gear and still get over 20mpg is just fantastic.

Thought i'd share

 

[Roots-type]

Head change with a stock tune and a lightning maf? Hmmmm

 

[na svt]

Head change with a stock tune and a lightning maf? Hmmmm

No tune on a c head swap is fine. No tune on a MAF swap is not okay.