Results after H/C install (Video)

[Ron 1995 R]

[nomedia="http://www.youtube.com/watch?v=AG-1Mt6gKi4"]YouTube- 95 Cobra R[/nomedia]

Went to Dyno last week.

Got an SCT tune; remapped the a/f curve; updated the part-throttle timing curve for today's fuel, updated timing curve, upped the idle (100rpm higher than video).

305rwhp @5400, 365tq@3600.
...did a good daily driver tune, not to within an inch of it's life (aka: the tune is conservative).

Stock numbers from another car/post for comparison:
- Dyno run # 1: 253.8hp, 323.6 ft/lbs of torque
- Dyno run # 2: 259.5hp, 324.8 ft/lbs of torque
- Dyno run #3: 251.2hp, 312.9 ft/lbs of torque


:beer:

PS: Tuner recommended anyone with an untuned car, aka original tune, have an updated tune done for todays street fuel.

 

[wheelhopper]

I like the side exit exhaust.

Who is your tuner?

I would have guessed that your numbers would have been higher after with new heads and a cam. What were your starting #'s?

 

[Ron 1995 R]

Sent you a PM on the Tuner

SpinTechMufflers.Com, they use to make a kit but no longer on their website. Also have a BBK H-pipe with cats.

I added the GT40X aluminum heads (no port work, changed springs) and a Comp Cam XE270HR-14 roller cam; with the 1.7 rockers that adds to 221i/227e Duration and .544" lift (advanced 1 degree). I was expecting more horsepower too, but this is at the rear wheels (figure +/- 350hp 415tq at the crank); with time more HP will come (things loosening up as well as the timing chain which will add about another degree advance OR I may just go in there and add another degree myself, there is extra P2V clearance with the dished pistons and shorter duration/higher lift cam).

 

[Powershift03]

Sounds GOOD! :rockon:

 

[TheWhistler]

Sounds great...

 

[94 Cobra R]

Wondering why you didn't port the heads and go with a custom cam?

 

[Ron 1995 R]

Wondering why you didn't port the heads and go with a custom cam?

Didn't want to go beyond the capacity of 24#/hr injectors and the mass air meter.

My calculations were the gt40x heads at .544 lift would be a 45-60 cfm improvement over the iron gt40 on the car. A cfm is (roughly) equal 0.9 horsepower. Add in the roller cam with a more aggressive profile and more lift with about the same duration as the factory cam (a bit more on the intake) and that's about 15-20hp. Factor them together and I gained about that much.

If I were looking for more flow I wouldve gone afr185 and definitely the bigger xe274hr-14. The intent was to swap to a roller cam and closely replicate the drivability characteristics. Basically my mods took away the parasitic drveline loss and made the former engine hp ratings now rear wheel ratings

24#/hr injectors are good for 340-355hp at the crank depending on fuel pressure, exhaust, and other mods.

Basically I didn't want to exceed the limits of the fuel system and drvability of the factory computer. Even my Tuner noted that the factory ECC has arflow/horsepower limitations so he was a factor in my decisions. Granted it is capable of more than what I did.

Thinking a 3.55:1 Rear gear and .82 5th gear is going be the end of the mods (maybe advance the cam in the near future); the car has a very broad torque curve). It's be a fun Pocono Mtns driver.

 

[94 Cobra R]

I see what you're saying. Just thinking you played it really safe with all of the old 302 (5.0L) items that you used instead of taking advantage of the breathability of the 351. If you were getting a custom tune, why did you want to leave the 24 injectors and mass air meter in place, unless you were just trying to save money? That motor drives so much better with 340-360 at the rear wheel as opposed to the crank.

 

[Ron 1995 R]

Wondering why you didn't port the heads and go with a custom cam?

oh...on the topic of custom cams.

I spoke with crane, the two popular custom cam guys, crower and comp.

Crane, comp and crower came back with very similar suggestions in off the shelf cams. Comp cams and the two popular custom cam manufacturers entertained custom cams. The selling point was comp cams would do a custom cam at A reasonable price, but their can guy said that for street driving and the occassional track day that either the 270hr or 274hr would be the best bet.

None of the cam recommendations came close to the .544 lift of the comp cam which I felt was critical to flow the Gt40x heads; and from what I understand both comp cams had much research and development intended the gt40x head. Crower and the two custom guys were around 206i/208e-115 lsa with .525i/.533e lift. Very similar to the ford racing 347SR engine. The higher it's revved the more power it makes; but I drive midrange and typically shift at less than 4500rpm; more typically at less than 3900rpm. So a high winding cam didn't make sense for me or the car.

Interestingly enough. I did find a dyno of a cobra r on this forum with the ford racing b cam; 1.7 rockers and 3.73 rear gears. His numbers were close to mine with 3.27 gears. Since gearing is multiplicative; going from 3.27 to 3.55 should yield about 315rwhp; 3.73 about 325.

 

[94 Cobra R]

Artificially, yes, gearing will give you the feel of that horsepower, but you should have gone with an Ed Curtis custom cam. Especially using old school X heads. He has been around forever. Going with an off the shelf, made for 302 cam was short changing yourself. But if you're happy, that's all the matters.

 

[Ron 1995 R]

Yep

 

[94 Cobra R]

That's one of the guys. Shows how much he impressed me, I forgot his name; I know he has lots of alcolades but I couldn't reach him to chat do he lost my sale. Problem with extremely low duration high lift cams are two things. 1) very sensitive to detonation. 2) valve slap on the seat due to down ramp speed. Could get any response on my concerns.

That's a shame. You still could've gone with a custom cam from Comp or Crane instead of off the shelf. No biggie, just interested in your decisions.

Last R motor I had made 540RWHP and got 24mpg on the interstate. Docile and idled perfect, even with the A/C blowing cold at a stop light. :beer:

 

[grape]

That's a shame. You still could've gone with a custom cam from Comp or Crane instead of off the shelf. No biggie, just interested in your decisions.

Last R motor I had made 540RWHP and got 24mpg on the interstate. Docile and idled perfect, even with the A/C blowing cold at a stop light. :beer:

i'm more impressed with putting a/c on an r car.