Clemson Sports Car Club

Jeff brought us his 1995 Cobra Mustang for some repairs, parts installs, and a tune on SCT. We started by repairing a "ticking" noise that he had, which turned out to be nothing but a broken spark plug.

Jeff had us replace his Shorty Headers with BBK long tube headers, install a BBK X Pipe, Trick Flow Nitrous Kit, and Autometer gauges and pod.






After the installs, Jeff's Cobra went on to the dyno.

Here is the setup:

347 Stroker Engine
Trick Flow Heads
Nitrous Cam
Roller Rockers
Trick Flow Intake Manifold
BBK Throttle Body

BBK Long Tube Headers
BBK X Pipe
Flowmaster Exhaust

#42 Injectors
Walbro 255lph Fuel Pump
Aeromotive FPR
Trick Flow Nitrous Kit (Jetted for 150 shot)

MSD Billet Distributor
MSD Plug Wires
MSD Ignition and Coil

Tuned on SCT. As a side note, SCT for OBD1 Ford Cars does not offer datalogging, even though all of their OBD2 programmers do on GM & Ford applications. On OBD1 Fords, we usually recommend Tweecer RT for tuning, but Jeff's ECU already had the chip for SCT.

Here is the chart from the motor tune:

This chart is without the Nitrous. This engine has a nitrous cam installed, which can have a slightly adverse effect on all-motor performance. After Jeff's bottle warmer is installed, we will tune for nitrous, and post those charts as well. Be on the lookout for update!



Click this picture for the video!

Damn - that's a pretty fat torque curve. I guess I am so use to seeing curves from engines with half the cylinders.

v8 for the win i think i see this guy driving around Clemson fairly often.

Also, it seems like power falls off pretty early on... Is that a result of the cam? Or the heads not flowing enough air? I know the stock 5.0's run out of breath pretty early too.

This car has Trick Flow heads, which flow very well. The power falling off up top is fairly common with Ford 5.0L engines, and is made more prominent by the cam profile, since it was designed for nitrous use and for a lower rpm stroker engine.

I'm really excited to see this car come alive on the bottle.

Completely unrelated, but those 5.0's sound sweet when revved high
http://www.youtube.com/watch?v=KZmUK6Qp82U

http://www.youtube.com/watch?v=04V_f9hOCCU


OHHH YEAH

On another note; more power was made, which in itself is more impressive considering it's a nitrous cam, however it didn't pass our heatsoak testing and ignition timing was appropriately reduced to prevent knock. We may revisit this aspect of tuning when he returns for his nitrous tune next week, and if we can extract more power on the motor while passing heatsoak conditions, then we will post and updated chart as well.

On to the technical aspect. As most of you are probably aware of, iron blocks tend to hold heat big time compared to aluminum blocks. We were able to find an extra 40-50whp over this chart but after the 4th consecutive pass while testing for heatsoak, the engine would start braking up on the top end (around 4.5-5k rpms) due to heatsoak despite 2 step colder plugs, and coolant temperatures in the 170-190's. Now that his setup is properly tuned to eliminate this brake up, he can enjoy revving to 6k rpms with confidence for the first time. Usually, one can use temperature compensation tables to adjust timing based on intake and coolant temps but iron blocks are not as forgiving as aluminum blocks. There is no point in more power if you can't safely put it down to the wheels consistently under all driving conditions..... Yes iron blocks are generally stronger but aluminum blocks are more efficient.

Customer plans to switch to E85 next spring which will help with heatsoak tremendously due to it's cooling properties which in turn will allow us to increase ignition timing to more appropriate levels and make more power, safely and reliably. Also, customer plans to jump from a 150 shot, to a 300 shot once he switches to E85.

Also, for those who are not aware, it's not always about reducing ignition timing. Reducing it too much will not only result in reduced power output, but it can actually increase Exhaust Gas Temperatures. You will need to find a middle ground between maximum power and consistency. Having the right tools, in this case a dyno, and knowing how to use such a tool (primarily through the smoothing factor of the chart), helps in determining not just maximum efficiency but a middle ground for reliability and consistency as well.

For those wondering how will timing be affected during the next tuning session for nitrous; theoretically, since timing is already reduced from maximum efficiency levels, little to no timing will have to be taken away for the 150 shot. Keep in mind the nitrous cools things down quite a bit. This of course may change if the setup is able to pass heatsoak testing with more advanced timing. We have a couple of thing planned to help with cooling the motor like lowering the temperature threshold at which the fans turn on and water wetter as well for next time so stay tuned.