disapointing dyno yesterday

[DRwepw4ng]

coastal dyno had a 2 pull dyno day for 40 bucks so i said what the hell. Got tuned there 7 months ago at 451/480 with a K&N, 2.85, no idlers, dented X pipe, weld in flows, gordsford heatexchanger.. myabe arond 13 #s.

yesterday on the dyno was barley peakin at 12#s and dropping almost to 10. The belt was glazed like a biotch and i was wondering how i prevent this from happening. Only dynoed at 434/440. Since the tune i got a FIPK and billetflow 4 price idlers to prevent this slip shit. im running a gates. 75.1 belt which was a TIGHT squeeze to get it on. i installed everything correctly, idk what else there is to do. HE said to maybe notch the tensioner to get a smaller belt on there but who knows.. is that my only solution? I should be at 13.5-14#s no?

 

[CobraBob]

Cats or off-road X-pipe? 14.5 lbs. of max boost would be about the average, but actual boost will vary depending on your particular intake/exhaust mods. Are you seeing any drop off around 5,500 - 6,000 rpms, revealing maybe some belt slip? Based on your setup, I wouldn't expect belt slip here.

When you went the first time your 451/480 was pretty much spot on what I'd expect. What was your other pull? How hot was it Saturday?

 

[Zorabot]

There is alot of power transmitted thru that little belt and its subjected to a huge amount of heat, I would expect the belt to be glazed and shot at about 10,000 average miles driven.
I am huge fan of a notched tensioner and a gates green stripe 74.5.

 

[DRwepw4ng]

^^ thats what im gonna try... weather was maybe 20 degrees colder when it made 451, but both days where shitty and rainy. the belt probally has about 5k on it.. im gonna notch and go with the 74.5 and see what happends.. Car peeks at 12#s and drops now i know its not gettin all of it. O/R X pipe( with dents ) and welded in flows.

 

[hpbyhermann]

Did you log the A/F before and after changing to the K-N??

It is very possible that the a/f has changed but the temp. differences are definately going to change your #'s. Make sure you log the A/F now to make sure you are still safe with your new CAI. :thumbsup: Hermann

 

[CobraBob]

Don't just install a belt size without verifying it is the size needed for your application. Otherwise you'll likely end up with a belt too small or too large. Use my Belt Selection Chart as a guide. http://stangshiftergaskets.com/BeltSelectionGuide.htm

You also need to factor in which Billetflow idler brackets you're using. If it is the newer one, add 1/2" to the sizes on my Chart.

If you are using an O/R midpipe (no cats) you're going to see slightly less boost. Sounds like you already know that.

 

[CPViolation]

It is very possible that the a/f has changed but the temp. differences are definately going to change your #'s. Make sure you log the A/F now to make sure you are still safe with your new CAI. :thumbsup: Hermann

Saw your car in a compilation KB Cobra video... Is it?
Nice!

 

[DRwepw4ng]

2.80
74.5" or 75"
K080745 or K080750

i have a 2.85 RR pulley, just notched the tensioner and threw a 0745 on there which is a 1/2 smaller then i had previously. I have the new style hub im assuming since i just got the idlers mayb 4-5 months ago.. NO improvement on boost levels. 1-3gear spikes at 12.2ish and falls down at 10#s at 6k, 4th gets up to maybe 12.5 and falls down to around 10#s as well... what the hell

 

[ViciousJay]

2.80
74.5" or 75"
K080745 or K080750

i have a 2.85 RR pulley, just notched the tensioner and threw a 0745 on there which is a 1/2 smaller then i had previously. I have the new style hub im assuming since i just got the idlers mayb 4-5 months ago.. NO improvement on boost levels. 1-3gear spikes at 12.2ish and falls down at 10#s at 6k, 4th gets up to maybe 12.5 and falls down to around 10#s as well... what the hell

i havent notch my tensior and im running a 74"

as fro your number there bout right... some see more boost others dont... id be more worried about power then boost....

 

[WDW MKR]

It's hot outside. You're going to see a loss in power and less boost. You're comparing to numbers from 7mo ago... Winter (yes, I know Florida doesn't see freezing temps, but it's still a lot cooler than July).

I've always had trouble with Gates belts glazing over in a short period of time. I run Gatorback and Polycog with great success. Opinions vary when it comes to belts.

 

[DRwepw4ng]

very true about the temps.. its just frustrating to not see the #'s i see others making.. im gonna wait till i get a real mid pipe/catback and put it back on the dyno in a couple months when temps arent 90+ and see what happends

 

[hpbyhermann]

Thanks for the props

Saw your car in a compilation KB Cobra video... Is it?
Nice!

It's out there in a few video's.......it runs a whole lot better now.....going to run it soon!:burnout: Hermann

 

[CobraVenom01]

david just face it...you car is slow...and my 01 is gonna eat it...haha...you gotta get ur car straightend out and race Andy in his terminator....we r doing a heat exchanger next week...ill give u a call bro

-Ryan

 

[speeddemon2000]

Time for a new belt.

Also check the following:
1. New plugs.
2. Run the IC pump with the car off to cool down the IC fluid.
3. Ice the blower
4. Check your IAT2 temps should be around 100 degrees.
5. Check your timing and A/F. 23 degrees of timing and 11.7 to 11.8 A/F
6. You might also try cleaning the filter.
7. If you are running cats they might be messed up.

If it's still down on power you may want to do a compression check.

Keep in mind like the other's have said you are going to lose some power with this hot weather.