While its safe. Lets talk openly about the B6/B7 S4 and the supercharger options

B6/7 S4/RS4
#1

Over the years many have came under fire for there criticizem of the supercharger options for the S4/RS4/S5

Its been at least 4 years of superchargers out on the market. Is it really still 5lbs of fail for the M90.

I think now we can have a open conversation about the good bad and the different. In the past it seemed to be more speculation and everyone giving the benifit of the doubt to the available supercharger options as there were no real results. Well the track results are in… what are everyones thoughts

#2

on a 4.2

Any roots smaller than a M112 - fail
Any TVS smaller than a R1320 - super fail
Any TVS smaller than a R1650 - mild fail

The motor is a 254 CID
revving to 7000 RPM
with VE ranging from 83-95% (just guessing on these values)

use:
http://www.ajdesigner.com/phpengine/engine_equations_air_flow_rate.png

Stock motor say 83% VE - CFM = 427
Piggies/Tune 85% VE - CFM = 437
Intake Mani/Catless DPs/Catback 93% VE - CFM = 479
Headers+everything 95% VE - CFM = 489

So figure a stock motor is 430, mild boltons is 440, a setup like my old S4 was 480 and with headers and everything maybe 490. If the blower is putting out an absolute maximum of 540CFM, you can see how on an otherwise stock car you are picking up a lot of air volume into the motor, but over a full bolton car you are more than halfway there. Add in the fact that the air coming out of the blower is warmer, which may account for a good deal of the increased air volume, and you can see how the M90 wasn’t doing a lot for the 4.2 (I say wasn’t because I don’t see many of these kits being sold or staying with the M90 anymore…)

#3

Beemercer. Great post.

Here is what I got, and its super close to what you ended up with, So I say great work. I have more information to back this up. Ill have to get to that later.

CID x RPM / 3456 x VE % = CFM All motor calculation
254 X 7000/ 3456 X 83 % = 427 This would be a stock motor
254 X 7000/ 3456 x 85 % = 437 This would be a chip Dp’s and some L/W
254 X 7000/ 3456 x 90 % = 463 This would be all the above + no cats more L/W
254 X 7000/ 3456 X 93 % = 480 This would be all the above + headers
254 X 7000/ 3456 X 96 % = 494 This would be all the above + the intake and throttle body
254 X 7000/ 3456 X 100 % = 514.5 CFM the motor VE can go up to 120%

We know the most Efficient the M90 can run is 60% and that isn’t going to be anywhere near 500CFM.

So if you ask me here is the Issue with the M90.

If you put it on a stock car your going to see a difference. That difference is going to come to a dead line in the sand when you get caught on the motors next restriction lets say for the sake of conversation the exhaust. So you can put the blower on but you will only be able to make so much hp out of the M90 due to the exhaust being so small.

So the solution is to get a better exhaust. Till you get to the next restriction… and then so on. By the time go get all the restrictions out of the way the VE of the motor went up enough that now the blower isn’t really doing anything beyond what the motor now makes.

#4

^The blower is just spinnin’ in the wind with full boltons lol

#5

Iiiinteresting. Makes sense as to why the full bolt-on s4’s do better than the PES s/c’ed ones.

I wonder if/when we have bolt-ons for the 3.0 if the same result will come forward with the m62 that PES uses for it.

#6

I would look for close to the same results. It really depends on how far we take it.

I chip and a good exhaust are going to really make a strong improvement. After that looking at the smaller stuff to see where the next restriction is will tell more of the story

#7

so bottom line - the M90 kits will get you a chunk of gains (certainly, cutting 7-8 tenths off off stock 1/4 mile times is a good chunk not to be ignored)…but will cap out at a level that is really not that far from full bolt ons…thus why deal with the aggravation and cost of a $10,000 supercharger kit (installed)?

i.e. 2.5" catback + 2.5" catless dps + JHM tune + JHM intake manifold (basically beemercer’s setup) will net you probably 95% of the acceleration gains that an M90 supercharger will. A replica of beemercer’s modlist can be had for:

$1300 (fast intentions catback) + $500 (custom 2.5 dps) + $450 (JHM tune on sale) + $1100 (JHM IM). That’s $3350, and if you have to pay for the full job it won’t be more than $1000 labour.

So…a bunch of very simple intake/exhaust efficiency mods + a great tune = SC performance for half the cost, and I think even the M90 supercharger guys would admit - FAR fewer headaches (jumping belts, leaking intercoolers, poor tuning etc…).

#8

Hell you can take the 1300 cat back and 500 for the down pipes and call it 1800. Add 700 to that your at 4000. looking at the results from the header cars on the 1/4 mile list and past dynos. Its clear the header cars make more TQ then the M90 cars. 1/4 mile wise the results are better for the header cars Vs the M90 cars.

From what Ive seen you can actually modify the car enough in exhaust, intake and chip to make the M90 usless. I remember seeing a dyno day result maybe from about 1 year ago where the M90 car only made 30whp more then a header car with no intake manifold but the header car made more tq. maybe some one can find that dyno stuff

#9

It’s amazing what basic logic and thinking a problem through from start to finish can result in. Too bad PES/VF didn’t take this approach when designing a kit for the 4.2 motors. It’s just ashamed all the people they’ve scammed by selling it to anyone with a 4.2 motor basically using dyno plots with ridiculous DTL estimations that can’t be backed up in the real world.

Just glad there are some people around to set the record straight & protect future potential buyers.

#10

I’d like to see more info on this JHM kit. Is it retail ready yet? Have any kit owners been to the dragstrip yet? I know they took their car and ran 11s with a baby seat in the back (lol) but I’d like to see what a downpipes + catback + supercharger would do…or piggies + catback + supercharger. Just to get an idea.

#11

Im going to say a lot of it is going to be in the tune.

Here is one good example to take into consideration
http://audirevolution.net/videos/52/jhm-supercharger-on-135,000-mile-stock-car

#12

I know there was a Vortech blog release with a video from JHM about the s/c, but I’ve yet to see anything official from JHM. I am looking forward to hearing some updates from JHM, as I would have expected something public already.

#13

what…is this your poker face? HAHAHAHAHAHA

In any event, if my car can run 12.9 with just downpipes, catback, tune, LWCP, LWFR and intake spacers…that should pretty much be the end of the PES and VF supercharger kits. My car ran faster than the VF Supercharged B7 S4 Avant. My car ran faster than all but 1 PES supercharged B6/7 S4.

PES kit + install = $10,000
VF kit + install = $11,000
my mods + install = $3000-3600 depending what catback you get

end of the M90 talk!

http://www.youtube.com/watch?v=c8G9bgOr_NY

http://i375.photobucket.com/albums/oo193/sakimano/fastest-2.jpg

#14

^ Hey, all I said was I’m looking forward to hearing something official from JHM, i.e. I want to see it on the website!

I never said I didn’t know anything or deny already having it, heck, I’ve loaded 2 dozen pics/videos of the kit on this site haha.