JHM Stage 1 Supercharger Dyno

B6/7 S4/RS4
#73

So in your original “I think avants are 150 heavier” did you mean the RS4 Avant is 150 lbs heavier than the RS4 sedan?
Cause if you meant the S4 Avant is 150 heavier than the RS4 sedan, you’re contradicting yourself by then saying that the “rs4 doesn’t have a spare but it weighs the same as a b7 avant”.

I know the RS4 doesn’t have a spare. I was basing my comment on your original statement that Avants were 150 heavier (assuming you meant S4 Avant seeing as that’s what we’re currently comparing to) and assumed the 150 difference already included the difference with the spare tire and jack situation. In other words, no point in adding that to my calculations because it was already taken into account.

#74

If you compare 2nd gear:

**EDIT: fixed my shitty math
RS4: 8000rpm (1/2.211)(1/4.111) = approx 880 rpm at the wheel

S4: 7000rpm (1/2.050)(1/3.889)= approx 878 rpm at the wheel

Then factor in wheel size…

Close.

#75

For fun:

http://www.kabamus.com/garage/gears.html

According to this calculator the difference in 2nd gear at redline would be less than 2 mph in the favor of the RS4. (68.15 over 66.35)

#76

i meant what i said…avants are 150 lbs heavier than sedans. That’s the weight premium approximately for an Avant over the same model sedan

RS4 weighs about120 lbs more than an S4.

So RS4 sedan is really close to S4 Avant weight.

#77

Ok, thanks for the clarification.
So if they weigh approximately the same, I’m about 100-120 lbs heavier with my box, cargo cover and junk. Not a huge difference.

#78

My RS4 weighed 3940. 1790 KG with a full tank.

Mistro probably weighs about 15-20 more because he has the premium package, and it has a couple of things like memory seat module, sat radio module, and the surprisingly heavy rear window automatic sunshade. So he probably weighs, stock car with full gas, about 3960.

B7 S4 sedan weighs around 3850. B7 S4 avant weighs around 4000 flat. So you’re 40 lbs heavier to start, then the variables like your roof box and the shit in your car, and whoever had more fuel etc.

Anyway, nobody has mentioned the speedo rate of increase yet…was it the same or different? Just heard a couple of rpm comments but what about the speed?

#79

Is that like speedo error? Or dV/dT?

#80

After all that, it’s tough to say and I’d call it pretty even overall. In other words, we’re really just wasting Internet space lol

#81

nerd

:slight_smile:

#82

Ouch man. You’re a meanie.

#83

Axel… did you have to ship your car to JHM for the SC install or did you just take it to a reputable shop near you?

I guess I should do a search to see if you have some kind of build thread on here…

#84

I don’t really have a build thread. Guess I should have created one at the beginning of my modding seeing as I’m nearly completely modded aside from headers and a few misc parts.

I plan on creating a thread describing everything I’ve done to the car at some point in the future but I’m still not finished with the car. Unfortunately, being out of a job has slowed down the modding (well, pretty much stopped it for now). I will be adding adjustable front upper control arms soon though as my original ones are worn out.

I didn’t have to send the car to JHM (that would be pretty nuts lol). A good shop in Toronto did the work. They’re close to JHM and are able to call them any time to have any questions answered. I think I might have been one of the first non-JHM SC builds.

Heck, if you’re good with tools, you can do it yourself (SpeedETC did). :slight_smile:

#85

Good to know! The mechanical part doesn’t scare me, but the tuning part sure does.

I had looked into a PES supercharger a couple of years ago but I was told it could only be installed at their shop or another licensed installer for that product, and boy am I glad I never went down that road. haha

#86

What part of the tuning scares you? It’s all been done for you by CountVohn :slight_smile:

#87

The tuning can be flashed via JHM’s server. i.e. you log into it following their instructions, using their cable, and load their file onto your car, remotely.

#88

The part of tuning that scares me is the actual writing of the tune. If someone else writes the tune… no problem.

#89

Well then, seeing as an expert in the field has already done all the work, you should be fine installing the sc yourself :slight_smile:

#90

why on earth would you have to write the tune? This isn’t a nine year old Subaru lol.

#91

Exactly why I wouldn’t want to do it. ;D

#92

We are just wondering why this would be a concern …all of the kits include tuning and fueling and the blower and fabbed pieces.