Roush Hesitation/Drag Thru Mid-Range

wsbrigham · Aug 15, 2005

Ever since I put a 66mm (2.6") pulley on ny Series II, my car has a noticeable hesitation/drag through the mid-range of the car up to about 500 rpm short of redline. It kinda' feels like someone is lightly applying the brakes on and off while I'm on the gas.

Hey Marcus,
I have seen in some posts that you might be able to shed some light on my problem....I could really use the help.

Thanks a bunch!

~ Billy
'01 S281-S/C #201
'99 S281-N/A Cobra Speedster #357

marcus95 · Aug 15, 2005

Have you had a chance to pick apart your air/fuel mixture at full boost after the pulley???

Also, what are you using for mass air?

Stock fuel pump?

wsbrigham · Aug 16, 2005

marcus95 said:
Have you had a chance to pick apart your air/fuel mixture at full boost after the pulley???

Also, what are you using for mass air?

Stock fuel pump?

My A/F is at 11.5:1 through redline. I am using the stock MAF sensor but my data indicates that I'm only at about 4V and not near pegging, which I understand to be around 4.8-5V....

Also, I'm using a SVT Focus fuel pump.

~ Billy

marcus95 · Aug 17, 2005

I would have to guess that it is a fuel issue. Are you 100% that your Focus pump is the SVT?

wsbrigham · Aug 17, 2005

marcus95 said:
I would have to guess that it is a fuel issue. Are you 100% that your Focus pump is the SVT?

Marcus,

I'm pretty sure it is the SVT Focus pump. Here's the information from my invoice:

Part No/Description: 3S4Z-9H307-BC

Is that the correct one?

Thanks!

~ Billy

BTW,
I have since added some Water Wetter to my intercooler and radiator and the majority of the ping has gone away. Could I be masking another problem, or is it possible that things may of just been running way too hot? My ambient intercooler temp was, on a 90+ degree day, running at around 160 degrees. Since changing my intercooler mix to 15% Glycol and the rest 50/50 water/Water Wetter, the temp has not exceeded 130 degrees.....the lag/drag still exists though.

marcus95 · Aug 17, 2005

Yea,

That's the correct part number. That Focus pump flows like crazy. Any idle issues whatsoever? You may have an intake leak. What about having the car tuned after the pulley install. I get scared when I hear about pinging that supposedly went away. I think your band-aid analogy may be key.

I don't like sitting here speculating about your stumble. That detonation is serious.

Ingredients:

Series II blown Saleen stock mustang.

smaller pulley

CAI

No tune

blown motor.

Scary.

wsbrigham · Aug 18, 2005

marcus95 said:
Yea,

That's the correct part number. That Focus pump flows like crazy. Any idle issues whatsoever? You may have an intake leak. What about having the car tuned after the pulley install. I get scared when I hear about pinging that supposedly went away. I think your band-aid analogy may be key.

I don't like sitting here speculating about your stumble. That detonation is serious.

Ingredients:

Series II blown Saleen stock mustang.

smaller pulley

CAI

No tune

blown motor.

Scary.

Scary; I agree. As a result, I purchased the SCT Xcalibrator II yesterday and I have dyno time scheduled for next Friday to try to get some of those issues resolved. I'll be sure to post the results when I'm finished.

You said something that has caught my attention, "...intake leak." The upper intake plenum (goes from the throttle body to the blower) was obviously broken/cracked where the bolts attach the throttle body to the plenum and was re-welded by the previous owner. Might that cause a problem (burrs, redges on the inside)? It appears to be completely welded, but I want to replace it. Saleen has quoted me around $600 and some change for a new one (ouch!). Does anyone manufacture a replacement to the Saleen Upper Intake Plenum? Maybe a throttle body/plenum combination?

Thanks, Marcus. Your input is greatly appreciated.

~ Billy

marcus95 · Aug 18, 2005

No problem Billy.

I didn't know about your "intake" fix. That's why problems are so hard to diagnose on here. I'm glad you are heading out to the dyno.
One guys weld job is not as good as another. Need to check that out.

Sorry I couldn't be of more help.

I hate stumbles.

Oh yea, call Joe at Chicane. Believe it or not I just saw a "few" laying around if you know what I mean. Maybe save yourself some of that 600 bucks.

Head Paneer · Aug 19, 2005

If you have to pay $600 to replace that intake piece, you might consider converting to the better flowing Series IV intake elbow.

FYR, the intercooler temp gauge on our car never exceeds 130 degrees, even in 90-degree weather with stock type coolant and no Water Wetter.

wsbrigham · Aug 24, 2005

Head Paneer said:
If you have to pay $600 to replace that intake piece, you might consider converting to the better flowing Series IV intake elbow.

FYR, the intercooler temp gauge on our car never exceeds 130 degrees, even in 90-degree weather with stock type coolant and no Water Wetter.

What series of blower do you have and is it stock? Also, what's your elevation?

Thanks!

~ Billy

S281SC#08 · Aug 25, 2005

I have the Series 4 blower im also in new mexico at 4500 feet and if you know new mexico it gets hot here and i have never seen anything over 130 on the temp

Head Paneer · Aug 25, 2005

wsbrigham said:
What series of blower do you have and is it stock? Also, what's your elevation?

Thanks!

~ Billy

00-0111 has Saleen’s primitive Series I with stock size (7-8lbs.) pulley, combination MAC/RIPP CAI and Magnaflow X-pipe with cats. The needle on the IC temp. gauge typically sits on the mark before the 130 degree mark. Elevation is about 30’ above sea level.

wsbrigham · Aug 25, 2005

Head Paneer said:
00-0111 has Saleen’s primitive Series I with stock size (7-8lbs.) pulley, combination MAC/RIPP CAI and Magnaflow X-pipe with cats. The needle on the IC temp. gauge typically sits on the mark before the 130 degree mark. Elevation is about 30’ above sea level.

Thanks for the details.

I'm gonna' wait until after I complete a couple of rounds of SCT tuning before I really try to figure out the temperature issue. Everyone I speak with says the problem (and others) are a little hard to trobleshoot w/o a tune for my configuration.

Also, I don't know how much of an issue elevation is with my temperature , but I'm at around 6000 ft above sea-level......

~ Billy

saleenster · Aug 27, 2005

Another idea to maybe think about is your fuel filter. How about spark loss? Usually on intake leaks, leaking air can be heard pretty easily. Stick your nogging near the blower and have a buddy/wife give it a little juice. Good luck on the dyno

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