As some of you are painfully aware, I have been having issues getting a good HP number out of my Comptech SC'd car. I am working with the same shop for all of this, with the same dyno and the same guy running the dyno.

The numbers are as follows:

Stock baseline: 199.3
SC'd baseline (8/20): 231
SC'd baseline (10/28): 219
SC'd V-AFC tuned (10/28): 227
SC'd V-AFC tuned, no airbox lid, element removed (10/28): 260

How in the world can the Comptech air filter cost me that much HP? Is there something else I am missing? Will a K&N filter flow better than the Comptech foam filter?

What filter comes in the Vortech kit? Is anybody running the stock Comptech foam and getting good dyno numbers?

Thanks for all of the support and info on this guys.

-YS

 

Yellow Streak- I know that your ordeal has to be frustrating. The only thing that I can think of is that maybe the map sensor is seeing some of the boost and doing some weird things with the ECU like pulling out timing and such. I know that some guys were having problems because of the check valve that wouldn't work properly causing the map sensor to spaz out. Most people I believe are now running the comptech esm instead of the check valve. The check valve kind of works when it wants to (sticks etc.) so I suppose that maybe your 260 run was the first run where the map sensor was functioning somewhat normally. By the way there is also a product called the smartmapper that replaces the check valve that does the same thing as the comptech esm , but is half the price. I don't think anyone on the board has tried it yet but that is what I plan on using when my SC goes in instead of the check valve setup. I hope this helps. Also from what I understand the foam filter is probably the least restrictive out of all the performance filters. (I believe that however it doesn't filter as well and isn't as durable)

 

If the MAP sensor was showing boost to the ECU, it believe would trigger a CEL. Either way, I am running the Comptech ESM and it works like a charm - the signal out of the ESM into the V-AFC is showing 0 boost. And, just to confirm, the MAP reading via the OBD-II port is showing that there is no boost either.

-YS

 

The first thing that came to mind: Check the pulley belt for tightness.

Second: If this is an older kit, you may have installed the ESM, but did you uninstall the CheckValve?

Third: What do your A/F ratios look like?

Fourth: What others modifications have you performed besides, Comptech SC, Comptech ESM, and the VAFC?

231hp with the Comptech SC? Something is very wrong. With a dirty air filter (I haven't EVER cleaned it) I'm still putting down over 300whp without any tuning. The kit will make an easy out of the box 270+hp. How much oil did you put on the filter? Who installed the kit? Have you checked your engines compression?

 

[QUOTE]Originally posted by jerrypeterson
[B]The first thing that came to mind: Check the pulley belt for tightness.

 

YS- It seems like you are right there with your numbers on the mustang dyno. Maybe you should just grab a different filter and see if you can pull good numbers with repeatability. A bad filter could definitely reduce power somewhat. I don't know about 30-40 horses though. Since the map isn't seeing boost and your not pulling any codes it is hard to say that the ECU is malfunctioning. You might want to see if the ECU is pulling out timing for some reason because that can drastically reduce power output as well.

 

On the street, about 2 months ago, with OBD-II diagnostic equipment hooked up, we watched the car pull timing from 44.5 degrees advanced to 14.5 degrees advanced under acceleration. I am under the impression that intake temperature has a huge influence on the car's selection of timing.

One theory with the air filter is that it allowed *much* cooler air into the blower which allowed the car to not pull out at much timing.

I am going to try a K&N as that is what Vortech and Speedcraft are using.

-YS

 

[QUOTE]Originally posted by Yellow Streak
[B]

A1. The belt is the correct tightness according to Comptech's instructions.

 

[QUOTE]Originally posted by Yellow Streak
[B]SC'd V-AFC tuned (10/28): 227
SC'd V-AFC tuned, no airbox lid, element removed (10/28): 260
The filter had a fair amount of oil on it, but it wasn't drenched.

 

[QUOTE]Originally posted by jerrypeterson
[B]

OK, Mustang Dyno different story.

12.5 is a scratch conservative, but that shouldn't have anything to do with the 30-40hp difference with the air filter.