Late fall after several months of tinkering with my NEW JHM NOS Kit I decided to see If I could get back on the leader board. While I love the JHM supercharger the JHM NOS kit offers IMHO a chance to get the benefits of the supercharger when you want it and the ability to go without when you want that as well. Not that you would ever want less power LOL. but for those power hungry guys like myself on a budjet its a good way to go.
I was hoping to make this post with better results then the below. As I wanted to spend more time on the car in full trim then the time I wasted with the switching of the exhausts. I feel if I spent more time on the car with the full 2.5" exhaust I could have gotten some better times. I wanted to go back to the track but the past few weeks I got rained out and now the track is closed for the year for me because I can’t get back now as I have no more time.
After all the years of debate and keyboard skeptics going on and on about exhaust systems and if they really made a difference for your 4.2, I decided to put years of research and tons of hard work to the test. While at the same time looking to see how well my Automatic S4 could fare at the local track with the help of the JHM nitrous kit. I was able to make several passes at the track as it was late Oct and only a few hard core racers were there. SO I packed up the truck and went to the track with a few good friends, a lot of tools, several full NOS bottles and 3 different catback exhaust setups.
The first to get tested was the 2.25 Milltek catback. I ran the car two times on the 2.25 no nitrous and two times on the bottle.
The 2.25 exhaust really IMHO killed the car. My best 1/4 mile pass on MILLTEK 2.25 + ALL MOTOR = 13.2 @ 106. It also yielded the worst 60ft times of the day with 1.9x. After you drive with a proper exhaust going to a 2.25 really shows how much it chokes the car off. I’ve read like 1000 posts where members ask “will I ever feel the difference between a 2.25 and a 2.5”. Simply, that answer is YES. Adding the NOS helped the Milltek but still left me with less then acceptable results. My best run MILLTEK 2.25 + NOS = 12.8 @ 110 . While I was really happy to see 12’s, it wasn’t the 12 I was looking for.
Next, came the tried and true JHM 2.5" X pipe catback exhaust. Even after driving back up to the pits. You can feel that the car likes the 2.5 better then the 2.25.
First pass on the full JHM header and 2.5" catback with X pipe was a win…JHM 2.5" X + ALL MOTOR = 12.88 @ 110 I had just done the same 1/4 mile pass with the car ALL MOTOR and just a proper cat back as I did on a 2.25" exhaust and NOS. Seriously now, IMHO for me this 2.25 debate is not only dead, but anyone that has said that you won’t be able to see a difference or feel a difference between a 2.25" exhaust and a proper 2.5" exhaust with a X pipe will in my opinion lose just about all credibility after this one pass. With the new JHM Launch ASSIST for the Automatic cars I Was able to hit nothing but 1.8 60’ launches EVERY TIME. I ran the car back to back to back and got the same consistent times. 1.88 60’ 12.88-12.91 and 109.7-110.8mph. First good pass on the JHM NOS kit. 1.88 60’ and 12.3@113.8. I let the car take a breather as I made sure to look over my times and look over my logs of the car. The JHM NOS kit was spot on. The RPM activation was right on and the safety cut off was also working great. I made the next pass with the same bottle pressure even though I wanted to turn up the pressure on the bottle it was getting late and I didn’t have many more runs left. Next pass 1.88 60’ . JHM 2.5" X + NOS = 12.27 @ 113.8. I could have done that all day long. Between the JHM Tune and the JHM NOS kit the car was deadly accurate and consistent.
BEST TIMES
- JHM 2.5 X + JHM NOS = 12.2 @ 113.8
- JHM 2.5 X + ALL MOTOR = 12.8 @ 110
- Milltek 2.25 + JHM NOS = 12.8 @ 110
- Milltek 2.25 + ALL MOTOR = 13.2 @ 106
2.5 vs. 2.25 = 6 tenths and 3 MPH with NOS
2.5 vs. 2.25 = 4 tenths and 4 MPH ALL MOTOR
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What I did notice on the all motor passes was that I was spinning right at what seemed to be right before the 60’. Anyone that has a header car will tell you that its easy to spin your 4 tires if you launch hard enough even when you have a automatic. The tq from the headers made it real hard to get a real good 60’ as if I really stood on the LA system I would come out real hard but I would spin the tires real bad and ruin the run.
I was happy with the 2.5" X all motor 12.88@110. That is impressive enough for me. So I decided to turn on the go juice. This is where the real excitement happened. I wanted to go for the gold out of the box. So I sprayed the car in 1st gear… and well that was a bad Idea. I felt like 91gl as I just blew the tires up in smoke and spun every time almost going into the wall. The Audi felt so strong footed you just sprayed and before you knew it what was a light wheel spin turned into a smoke fest and you were headed not straight anymore but it was like you were skating on ice when the JHM NOS kit hit. So the first few NOS passes were not full passes. I then decided that I was going to not spray the car in 1st gear. This should help me get out of the 60’ range and then I can let the JHM NOS carry me the rest of the way. I also lowered the bottle pressure on the bottle. I found that the higher the bottle pressure the harder the NOS will kick. So I took the pressure down by almost 200lbs. I knew this was going to cost me big performance but I wanted to just play it safe.
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Timeslips for proof. We tried to take video and we have some. The issue with this track is there is no score board. So if there are any questions on the times. There were several other forum members that were there that day and you can also call the track to verify the times.
http://farm7.static.flickr.com/6216/6322767041_a2df6c8678.jpg
http://farm7.static.flickr.com/6222/6323293642_ebcbf58ce6.jpg