Results of my CATBACK + PULLEY dyno

[speedemn]

Okay as posted earlier, the cat back was quite a success. I had the "Unorthodox" underdrive pulley installed this week and took it to dyno yesterday evening.

As luck would have it, it was raining like crazy and very humid. Overall readings were a little lower than normal. Now one important variable here is the guy doing hte dyno run. I've had the same guy do my first 2. However this time that guy wasn't there and another guy did it for me. He wasn't as good in my opinion. Anything below 4000 RPM was inaccurate and had to be trashed. He got on the pedal really soft until 4000 RPM which is when he floored it. So under 4000 RPM it looks like I have NO POWER! However here's the results of the pulley:

Peak HP was up a bit... 2 HP or so and torque remained the same, at peak again. HOWEVER, at higher RPMs, there was as high as a 6 HP and torque increase. In other words, my HP and torque curves have flattened out a bit, at the top end at least. Who knows what the real effects were at lower RPMs (under 4000). But from driving it, the RPMs climb faster, obviously I'm making more power at higher RPMs now than I used to, so you don't get that steep power drop after about 5000 RPM.

That's it for now. I don't know what my next mod should be. I think I want a high fow cat and maybe work on the intake a bit to make it cold air or ram air. I dunno yet, because the exhaust was amazing and I don't want to disturb the balance with backpressure and all that, by incorrectly modifying the intake.

I might just ask Richard at Brullen to take a look at my cat since he did my exhaust. I'm sure he will find a way to modify cat without losing benefit of cat back and give more power overall.

[EKam]

It's good that even though the result is not great (because of the weather) you actually feel the difference after putting in the pulley. That's what it all matters. :wink:

BTW, does your car scrape when you pull it into Brullen's garage?

[speedemn]

I am curious as to whether the result wasn't what I expected because of:

1. the weather
2. the guy who did it (he sucked compared to the other guy in my opinion)
3. the pulley itself isn't as good as (JRP/Unorthodox) claim it to be
4. any combination of the above

But the fact remains that on the dyno as well as seat-of-the-pants feel, top end is much better. I also got a graph showing my baseline vs catback+pulley. I've gained as much as about 12 HP and 12 lb.ft at as high as 6000 RPM!!! It is very difficult to get a good low RPM dyno with an auto tranny, since you can't lock it in 2nd gear and it is so willing to downshift before 4000 RPM. That's why yesterday's graphs were pretty much useless under 4000 RPM. I wish Jeremy (the first dyno guy) was there. He was able to get me 3000 RPM and above. That at least gave me some idea of what my low end is doing.

On 2001-09-21 11:52, KaMuRi wrote:
It's good that even though the result is not great (because of the weather) you actually feel the difference after putting in the pulley. That's what it all matters. :wink:

BTW, does your car scrape when you pull it into Brullen's garage?

[Jzs147-RR]

I always do my own dyno runs for lower rpm ranges cause some dyno guys are crap..Well from what i can see the weather did screw-up your dyno but remember any gains are good.

[SW20 MR2]

Why would the dyno operator have anything to do with it picking up the signal? They just put the clip on the plug wires.

The gains from the pulley sound decent. I would much rather have 6whp in the middle of the powerband and 2whp up top instead of 2whp in the middle and 6 more peak whp. It makes the car much more driveable.

[bondobondo]

hi flow cat = waste of money..

stop reading SCC.............

go for schooling at brullen,
ask for richard. =)

[speedemn]

Ummmm... that's who did my cat-back and is offering to do my hi flow cat :smile:

On 2001-09-21 21:57, trueno92 wrote:
hi flow cat = waste of money..

stop reading SCC.............

go for schooling at brullen,
ask for richard. =)