So I went to the dyno today in hopes of getting my car dialed in for the BBR stage 1 cams. I had doug from bamachips helping me remotely and reserved an hour for tuning which ended up taking 2 hours. Thar car put down good numbers from 3000 rpm to redline, but there is a big problemfrom 1500 to 2500 rpm. the torque curve starts out great, and then takes a HUGE dip finally recovering at about 2800 rpm. on the datalog the load takes the same dip as the torque curve does, and the timing retards right along with it. Doug tried to tune this out and succeeded for a moment but the car went back to the same old thing. it seems to me the timing retard curve is coming from the load curve.

on the dyno sheet attached are two runs. the solid line is where it was fixed for a run, and the other is the final run of the day. the xls files is actually the .csv from the funky run. just rename it to a csv if you want to view it.

any help would be sooooo much appreciated!!!

 

wow all kinds of views and no replies. no love for the faber?

 

First you need to figure out what is under so much load. Fuel pumps, injectors, etc etc.

 

Hey Faber...why are they starting your pull at such a low RPM?? It is hard to see your dyno sheet but here is mine from Brenspeed on the 15th with Oct's stock cam pull and the Comp NSR Cams pull on the 15th. My WOT pulls was started up higher in the rpm range! Did they smooth your results?
Scott

 

Since installing the cams I have been experiencing a wierd loss of low end power. power comes on strong from idle to about 1800 rpm, and then falls on its face. it picks back up real strong at 3000 rpm and pulls hard to 6200 rpm. we were having a hard time with my mac cold air intake so I bought a C&L racer since bamachips has done so much R&D with that intake I figured it would be easier for him to tune with it. I was going for just a new baseline run but got doug on my computer remotely so I figured I would shell out for some dyno time and get it dialed in. much to my surprise the low end torque was worse than it was with the mac intake. now normally I would chalk it up to the cams or the intake, but doug sent me one particular tune that got the low end back, but only for one run. so we focused on ironing out that low end torque loss and that is why the runs start from lower rpms. I am happy with the gains up high, but the car is a dog from a dig (pardon the pun).

wierd thing is yesterday I got a tune from doug that was just for the stock cams since I was going to pull the cams this weekend and go back to stock. I took 6 degrees of timing out from 2k to 4k and added 1 degree globally and the low end got better.

it looks like the load is going away at about 2000 rpm and then coming back strong around 3000 rpm. the timing advances quite a bit during this time and I think that is what is causing the funk. too much timin from 2k to 3k.

cant figure out why the load would go away like that though...

 

Johnny, ol' boy,

Ford uses the term "load" for volumetric efficiency. V.E. is calculated using:

Engine revolutions (rpm),
Mass air flow rate (lbs/min), &
Intake air temp.

at least according to this:

http://www.installuniversity.com/ins...n_9.012000.htm

This may help as I'm not sure exactly what method Ford uses. Or if this doesn't help, try posting your question here:

http://www.sctflash.com/forum/forumdisplay.php?f=72

and if that doesn't work, call James at SCT. He's the most knowledgeable dude I know at SCT: 407.774.2447, Ext 124.

 

Johnny,
This world is full of tough decisions. It is either this or that and rarely both. I believe that you got the lopely (AWESOME SOUNDING) idle and I got more RWHP from a set of cams. Don't take this wrong....you got the idle...I got the power! I am not sure you can get both?
Scott

 

Generally speaking, the lopey idle comes from an increase in valve overlap, which is also generally associated with higher RPM capability. The shift of powerband upwards necessarily will cost you down low. If the valve events are tuned for low-end grunt, when you spin the motor faster, the valves are opening and closing faster than the motor can suck in a full air charge (and exhaust it), but if you slow the valve timing down to allow the engine to breathe properly at high rpms, the valves are hung open too long at lower rpms. The VVT can help with this some, but the profile will still wind up being tilted one way or another.

If you get a cam profile that's geared for higher RPMs, though, you'll need to make sure that the valvetrain is up to the task, and you need to make sure that the engine can flow enough CFM to prevent a bottleneck, and your drivetrain needs to be optimized to use the higher rpms in your desired speed range. The upside, though, is that you can make a lot more power up in the stratospheric rev ranges...

 

Well the problem is solved. thanks for all the input guys. I ended up re-installing the charge motion plates and my low end power is back BIG TIME, it is amazing. top end feels the same also. I will re-dyno soon and see what the numbers say. the car has a seemless power delivery now where before there was a big bog, and then it woke right up at 3000 rpm and pulled like crazy.