lorie

I am loosing boost. Can anybody help me out?
Or is it regular 12.3 psi boost by this modifications?

mileage: 25.000 miles

168 mm pulley
3 mm (0.12") milled of (supercharger pulley)
82 mm TB
kleemann cams
longtube headers (supersprint)
cats delete
resonator delete
ECU
slip differential
3.06 differential

> only 12.3 psi boost

GT-ER

You may have belt slip, although it could just be your mods. I get 14psi but I have a 178mm pulley and no cams.

stevebez

err you have a 3.06 rear diff??????

bnzuovr

How are you guys reading your boost im also curious if im losing boost?

Toadster

maybe I/C pump is failing and heatsoaking you to turn off the S/C ?

bnzuovr

If the I/C pump is going i don't belive it would make any boost and would come and go with the power if im correct.

Tech-Tune

I dont think your loosing boost. Your particular mods have made your engine more efficient (especially the headers and cams).
If you want more boost I'd go with a larger crank pulley.

TTMotorsports

You are exactly where you should be with long tubes, unrestricted exhaust and that small of a pulley.

Just enjoy it!!

chawkins2001

I make 14psi with a 195mm pulley, so I would be happy with your boost results with a 168mm.

lorie

On the dyno!

Yes! It is rare!

The IAT is perfect. I am running a modified KC.

I am a daily driver! I don´t want to get bad IAT.

From 180 mph until final velocity there is no power.
Before mods I am running a 172 mm pulley with 15.2 psi (maximum)
I am very unhappy. I don´t know if the new mods swipping the boost.
12.3 psi makes me dissatisfied!

Only by running a 168 mm pulley I got 13.8 psi (without cams and headers).

chawkins2001

Who cares how much boost you make man, as long as your HP has increased under the curve since your new round of mods, that is all that matters. You are probably making more power now with less boost, and that is exactly what you should strive for!

xpl0sive

i think you are feeling no power after 180 mph is because of the 3.06 rear diff... if you had the regular 2.55 rear diff, you top speed would be better... 3.06 is better for acceleration

Tech-Tune

Your boost is fine.

I agree with ^

lorie

I don´t talk about about top speed. Top speed is 202 mph with 3.06.
There is no power and by running 3.06 instead of 2.65 is more advantageous to climb fast to top speed.

For about 4 weeks my car was running stronger with the same mods.

sergs99m3

Your Boost level is accurate with your upgrades.

GregMB

The numerically higher rear gear should make the car pull harder in top gear... He is just trading odd some top-end MPH.

What sort of RPM are you at at 180MPH? Are you doing any data logging to capture ignition timing, IATs, etc? I'm surprised that there are no fuel system mods in your list...... Long, top-gear pulls at WOT are pretty tough on the stock fuel system. I wonder if you are either running out of fuel or the injectors are at 100% duty cycle (static) at those kinds of speeds.


-G

justinwrock

Can you please share information regarding your differential? (What its out of, if its an LSD, and how you made it play nice with the TCU)

GT-ER

This is correct. Higher gears make the car accelerate faster in every gear at every rpm, they just limit the top speed ( this is without discussing wheel spin and fuel economy ).

As for the fueling, he must be running SOMETHING other than stock. I have a lot less stuff than he does and my car was maxed out on the stock fueling.

lorie

No I have no data logging and no fuel system mods.
At 180 mph exactly 6000 U/min
At 192 mph exactly 6400 U/min


My mechanics solved the problems with the diff.

What is the advantage by running fuel system mods? With ECU you can adjust to run it rich.

Tech-Tune

Translation: I prefer not to share this information, but would still like answers to my questions/concerns.

kustom2k1

Your not on a closed road, are you? Your gonna get your a$$ beat with a billy club

168 pulley making 12.3lb of boost, something wrong with your gauge homie.

GT-ER

You have no fueling mods? You can tell the ECU to run rich but our injectors are pretty small so they max out at about 500-520whp. Any higher than that and you start to run lean. You have a lot of mods which should put you at around 550whp I'd think, and without any fueling mods I bet you are running pretty lean and the car is pulling lots of timing which could explain your car running slower up on top.

You REALLY need to datalog and you REALLY need injectors.

skratch77

I feel bad since im only seeing 12.0-12.8 lbs with a 178 pulley depending on how cold it is Ill see a tad over 13lbs sometimes also and you are crazzy to do 180mph like that.

320 dreamer

can you tell me who your mechanic is? we can ask him about the diff.
amazing thing these motors, with my v/6 i push 16 psi avg and 19 psi on a cold day. stack the pullies and you get 25 psi!!

lorie

The diff is a new one from MB from sl 65 amg black series.
the LSD is from wavetrac. How it made to plays nice with the TCU ask my mechanic at www.sportwagenwerk.bcd-ost.de and www.vortrieb-dresden.de


Dude chill and talk reasonable to me.
The oem boost is already 11.6 psi.
By running a 172mm for month ago I had a peak of 15.2 psi on dyno.

The engine runs at 0,85 lamda.


I hope you are good in german!
www.sportwagenwerk.bcd-ost.de