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Discussion Starter · #1 ·
First off, with just the Dynomax catback my car ran a 14.075 @ 99.26 mph last July. I have since installed a MAC O/R H and took it out this weekend. The best I could get was a 14.054 @ 99.83 mph. :mad: Same amount of gas and everything. What gives?? It doesn't sound like I have a leak, but that's the only thing I can think of. I never sealed the crossover, I don't want to weld it, cause I'm not sure I could remove the pipe if I did, it would be close.

Anyone else had the same results? I'm really bummed, I was hoping for 13's at 101 mph.

FWIW I also pulled the silencer for the last few runs and didn't see any gains, so thats back on.
 

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Well think of it this way. If you want to see the hp gains dyno it before and after. I know you gained some power, but it isn't going to get you much in the 1/4 mile. Also, you can usually get much better times just by running your car down the track more and getting experiance.
 

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Discussion Starter · #3 ·
havok735 said:
Well think of it this way. If you want to see the hp gains dyno it before and after.
I'm more interested in real track results. Besides mph is usually a good indication of horsepower.

I know you gained some power, but it isn't going to get you much in the 1/4 mile.
I believe the H pipe (especially O/R) should be good for at least a tenth and a mph. I personally know people who have got better results with a catted one.
 

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Discussion Starter · #5 ·
Hey Jim , it was in the low 70's. I was looking for you there (Tri-State), you were there when I ran last year. I haven't seen you run the black stang yet.
 

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Discussion Starter · #6 ·
What did everyone else gain when switching to an X/H pipe? I think I'm the only one who didn't gain squat.
 

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On my car (yeah, it's a Cobra so the numbers will be different) I picked up 25rwhp with just a Bassani X (w/cats). Switching to an offroad H didn't get me anything other than a great exhaust note. :)

I would think you'd get at least 10-15 flywheel hp out of an H pipe swap, that seems to be the norm. Weather and/or traction can make a huge difference in times too, so just because this one time you didn't pick up much doesn't mean you didn't get any more power.
 

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I had the same problem all last year.

With my Sportlines, Tri-Ax, K&N, and welded 2 Chamber Flows......the best I could run was a 14.1 @ 98 mph with a 2.1 60'.

Added the Offroad H, and all I could run was a 14.1 @ 98 with a 2.1 60'.

Ran 3 or 4 times last year with each setup....every time I ran the same thing.

Last weekend I went to the strip for the first time this year. Every run was a 14.0 @ 99 or better......that is before I broke.
Ran a best of 13.82 @ 101.5 with at 2.093 60'. No new mods, just regular maintenance. I did try launching higher and feathering the clutch though.

Had 4 runs between 13.82-14.04 @ 99.7-101.5. Each run getting better.

My 5th run I aborted cause of a bad launch (water on the line).

Ended up breaking my throttle cable on the 2-3 shift on my 6th run. :mad:

In a couple of weeks I'm going to try to back the times up.
 

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There are so many variables you have to include in your comparison: Barometric pressure, humidity, wind speed/direction, traction, launch technique, shifting rpm/technique, etc.
I've varied as much as 3mph in seemingly not too different weather conditions with the same setup.
The H is worth at least a tenth and 1-1.5mph in the 1/4. FWIW, the BBK O/R H is worth 8-10rwhp and torque across the board vs. a O/R Bassani X.
 

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Discussion Starter · #11 ·
Thanks for the replies guys,
I believe the temperatures were about the same. It was a little more humid this time out as it just rained earlier in the day. However there was a slight 5 mph? tailwind this time. Here are the two slips.....

Last Year / H-Pipe
60' 2.160 / 2.198
330 5.952 / 5.993
1/8 9.104 / 9.119
MPH 78.10 / 78.85
1000 11.802 / 11.795
1/4 14.075 / 14.054
MPH 99.26 / 99.83

Yes my 60' ft times suck. I plan to work on that. :eek:

I was just expecting more MPH out of the car even with the poor 60'. I know the ET will fall with more practice.
 

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Discussion Starter · #12 ·
JIMS SVT said:
Maybe be there on the 6th.First thursday of test and tune.See you there ?
That just might work I'll have to let you know next week.
Black Hole, are you game too? We can run our two slow twin black turds against each other.:D
 

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Well your 1/8th mile speed is up .75mph, that's a good sign. Maybe you can pinpoint your disappointment in the last half of the race.
 

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Unleashed said:
Thanks for the replies guys,
I believe the temperatures were about the same. It was a little more humid this time out as it just rained earlier in the day. However there was a slight 5 mph? tailwind this time. Here are the two slips.....

Last Year / H-Pipe
60' 2.160 / 2.198
330 5.952 / 5.993
1/8 9.104 / 9.119
MPH 78.10 / 78.85
1000 11.802 / 11.795
1/4 14.075 / 14.054
MPH 99.26 / 99.83

Yes my 60' ft times suck. I plan to work on that. :eek:

I was just expecting more MPH out of the car even with the poor 60'. I know the ET will fall with more practice.
I would say that your car showed a benefit from the offroad h-pipe. Look at the last 1/2 of the track on both slips vs. the 1st 1/2. You had a ****tier 60' time with the offroad h-pipe, but finished faster at the upper end of the track.

As said above, you really do need to consider weather in order to compare. That's why dynoing is suggested, because you can calculate to correct for temperature, humidity and pressure to equivocate hp.

Don't be upset, it's a solid mod, like Fourcam said.
 
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