Just got back from getting the motor dyno tuned and have a few issues. One, they said I need to set the IAC, but I don't know how or know what I need. The other is different springs, apparently the springs I ordered with the cam from Comp will not hold upto the lift they should and three the plugs were all fouled from having a 5 & 7 injectors on the wiring harness mixed up. Only dynoed at 263 RWHP and 278 RWTQ on a mustang dyno in Denver, CO which is appox. 5800 ft. They're puttin in new Manley nextek springs for me, but I have to get the plugs changed and the IAC set if I can figure it out. He said the cam should pull to 6500 easy and make at least 340-350 at the wheel without knowing my head flow # 's. The horsepower literally straight lines down at 5500 rpm. What do you guys think, and does anyone know how to set the IAC and what I need to do it.

 

IAC wont make any difference on the dyno. What springs are you using?

 

Here's a write-up from Shoebox's site on setting the IAC for a 1995; don't know if the '97 differs:

http://shbox.com/1/4th_gen_tech2.html#iac_reset

 

I realize the IAC has nothing to do with the dyno, but it does have something to do with it not wanting to idle back down until you shut it off to restart the PCM. Here is the specs on the springs that were used.

Valve Spring Diameter 1.430'', 2 Spring
249-986-16 Hi-Tech Dual Valve Springs
Seat Load: 132# @ 1.750''
Open Load: 280# @ 1.250''
Coil Bind: 1.150''
Rate(Lbs./In.): 296#

Tell me what you guys think. Tech at Dragon Race engineering thinks I'm experiencing valve float and can't even hit this cam's max performance.

 

I agree you need more spring. A lot of people use the 987 spring which seems to work.. thats what I have with my 224/230. And then theres the 918 beehive that can handle some radical, high lift cams.

 

I had 987's and they were decent at best, requires machining of the spring seat. 918's can be used on stock heads, and they have AWESOME pressure. Also being a beehive constuction, less valve train weight, even if you use the steel retainers, compared to the 987's

 

The tech at Dragon Race said they have even had trouble with the Beehive springs, and recomends that I go with these Manley Nextek's. He claims even the beehive springs will weaken after 3000-4000 miles. He said he has put these Manley's on cams with up to a .650 lift with no issues. Thanks for all of your guy's input on my current springs.