Mercedes-Benz Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
2,282 Posts
Discussion Starter #1
I would highly recommend the installation of a manual boost control on any Turbotechnics or Mosselmann twin turbo M103 or M104 setup.

Not even considering the ability to incrementally increase boost, but more for the fact that it synchronizes the independent turbos.

I used a Hallman Pro RX primarily for it's design and light spring which allows fine tuning of boost adjustment.
The turbos spool up faster and by using the boost/control signal from the rear turbo only to open the wastegates gives identical performance to both turbos.

You must first install a boost gauge.
After installation of the MBC adjusted fully counter clockwise ( no increase over wastegate adjuster arm setting), I confirmed via a road test my set 7psi +/- mechanical setting.

What I noticed is that the boost is held at this level without dropping due to the inaccurate mechanical settings.

Haven't been able to road test a half turn increase as it started to rain.

Trying to get dyno time and 1/4 results in the next week or two.

Ed A.





 

·
Registered
Joined
·
682 Posts
ed, is this a new thing you have just fitted? please tell us more details, how when cost ect............... please please!!
 

·
Registered
Joined
·
2,282 Posts
Discussion Starter #4
ed, is this a new thing you have just fitted? please tell us more details, how when cost ect............... please please!!
Nick

Inexpensive....just fitted yesterday.
Raining so I can't use too much power in a road test !!

About $100.00 for the Hallman MBC and $40.00 for a quality mechanical boost gauge.

Tee'd off the stock vacuum/economy gauge to feed the boost gauge.
Picked up light for the boost gauge from the cigar lighter feed connector.
Mounted the gauge in a single pod on the passenger side of the console.

The MBC takes about an hour...

Removed the hoses from the boost port to the waste gate actuator on each turbo.
Blocked off the boost port on the front turbo.
Ran tubing from the rear turbo boost port to the MBC inlet.
Tee'd together the wastegate actuator ports on the turbos and ran the line to the MBC outlet.

The rear turbo alone controls when both wastegates open...and they open at the same time.
The Hallman unit comes with a light spring installed so you can fine tune under one bar setting.

I road tested with the MBC at full null and had my 7psi.
Turned one half turn to add boost and looks like I'm around 8psi.

Will make final settings and compare my boost gauge with the dyno gauge when I get some dyno time.

Spools up much faster..holds boost even at steady pedal pressure...before my boost would drop in and out with steady pressure...

Inexpensive but I think it's important to synchronize the two turbos !

Ed
 

·
Registered
Joined
·
2,282 Posts
Discussion Starter #6
Are the turbos in those setups variable-geometry-blades turbos?
No just plain fixed blade seventeen year old Garrett T2's !

VGT has been used on turbo diesels for a while, but fairly new on gas engined auto appplications.
 

·
Registered
Joined
·
1,006 Posts
VGT has been used on turbo diesels for a while, but fairly new on gas engined auto appplications.
Exactly. Most new TDI engines have it. Guys who specialize in diesel tuning swap the fixed blades for VGT for better torque throughout the RPM-band.
I think that Porsche introduced those in Turbo model... Do You think there would be a lot of trouble in swapping the turbos on W124?
 

·
Registered
Joined
·
2,282 Posts
Discussion Starter #8
Exactly. Most new TDI engines have it. Guys who specialize in diesel tuning swap the fixed blades for VGT for better torque throughout the RPM-band.
I think that Porsche introduced those in Turbo model... Do You think there would be a lot of trouble in swapping the turbos on W124?
I'm not sure upgrading to a VGT would return much more performance for what it would cost.
There are actuators involved and the M103-12V KE-Jetronic III is so basic that it would require going to an EFI system that could produce signals to the actuator.

I'm old school and like to get the most power out of what is as close to original as possible !
 

·
Registered
Joined
·
682 Posts
ed, please please tell........ how much boost can you make the t2s produce? turn the knob till it stops and let us(me) know what they can puff coz i am dieing to know how much more than 7psi is possible.
 

·
Registered
Joined
·
2,282 Posts
Discussion Starter #10
ed, please please tell........ how much boost can you make the t2s produce? turn the knob till it stops and let us(me) know what they can puff coz i am dieing to know how much more than 7psi is possible.
Nick

I probably won't go more then 9-10 psi...
Need to first see the boost curve and power at 8psi.

The T2's are good for at least 1 bar+

Ed
 

·
Registered
Joined
·
191 Posts
Ed,
Random question......whats the A/R ratio on your T2's?

BTW, once again......your car is just SOOOO clean. Looking at how bright the aluminum engine heat shield on the firewall makes me want to cry :bowdown:

W124 love, better yet M103 love :thumbsup:
 

·
Registered
Joined
·
2,282 Posts
Discussion Starter #12
Ed,
Random question......whats the A/R ratio on your T2's?

BTW, once again......your car is just SOOOO clean. Looking at how bright the aluminum engine heat shield on the firewall makes me want to cry :bowdown:

W124 love, better yet M103 love :thumbsup:
How can you not love a M103-12V...it's like the original small block Chevy !!!

I believe the A/R of the T2 is .48.
 

·
Registered
Joined
·
682 Posts
just bringing the thread to the top so i can find it easier tomorrow!!

i'm gona fit a mbc and see if it cures my lack of boost, dont want to just block the wastgate shut, the engine is still newish from rebuild, might damage it(just my luck)
 

·
Registered
Joined
·
2,282 Posts
Discussion Starter #14
just bringing the thread to the top so i can find it easier tomorrow!!

i'm gona fit a mbc and see if it cures my lack of boost, dont want to just block the wastgate shut, the engine is still newish from rebuild, might damage it(just my luck)
It's an easy task Nick !

While you have everything apart you can hopefully get the c-clips on !!!

Ed
 

·
Registered
Joined
·
682 Posts
ok,its fitted.
I have turned it right down, and it seems to be boosting to 2psi, but still dropping off, i spoke to a friend who turbos v6 fords, and he said my inlet pipes from the airfilter to the back turbo might be collapsing, and causing an air lock, apparently he put a cozzy lump in a mk1 escort, and had all sorts of problems with it, because of the same thing happening on his inlet hose!
 
1 - 15 of 15 Posts
About this Discussion
14 Replies
5 Participants
nick.ged
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Top