Has anybody tried to modify a 190 gasser instrument cluster "economy gauge" to be a boost gauge for their 190D 2.5 Turbo? As far as I can tell on a gas car, at idle the vac pressure would be about 18 to 20" and would put the needle all the way to the left side (black side) of the economy gauge, and at full throttle it would put the needle all the way to the right side (red side) of the arc which would indicate roughly atmospheric pressure...

Sooo...from what I've calculated, 18 to 20" of manifold pressure equals about 10 psi...so if I re-index the economy gauge needle all the way to the left (and assuming the 190DT's max boost pressure is between 10 and 11 psi), my "modified" economy/boost gauge should peak out right about the top of the red zone at 10 to 11 psi full boost pressure...yes????

I'm messing around with a gauge I have on hand...I'll have to change the face to an earlier 190 one which didn't have a "premium fuel only" notation on it and just has a picture of a "gas pump" instead...trying a Brother p-touch label maker to make the "Turbo" notation...wish they had matte black tape with white lettering...I've only found gloss black tape...

Thanks, J.G.

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jbaj007 did that many years ago. 124 and 126 economy gauges have about 7 psi between posts. I set the indicator to lift off one post at 5 psi and peg at 12 psi. That means lifting the indicator over the low end post and letting it settle, pulling then refitting the indicator at about the 10 o'clock position (trial and error), then lifting over the low end post into the display range. It works for me since 5 psi is about the point the turbo makes itself known and anything beyond 12 psi is gravy

Sixto
83 300SD

Likewise on my 617 diesel swap into a 107 (380SL). The 107 has the economy gauge and it's just a matter of recalibrating the gauge for boost by repositioning the needle. It still says "economy" but I know what it is. I used a boost gauge and a pressure sprayer to calibrate and make tick marks every psi. Works perfect, though mostly I just monitor boost on my steering wheel mounted tablet along with 9 other engine performance values.

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

Excellent idea. Much less offensive in the interior than a makeshift tire/boost gauge. Only an experienced eye would catch this.

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'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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Thanks...I ordered a "Mityvac" vacuum AND pressure tester to do my gauge needle calibrating before I actually install it in the car. Only want to do this procedure ONCE since the cluster is a bit of a pain to R&R! (...also have a separate calibrated boost gauge that I will use to verify all my readings) Sounds like it should be pretty simple. Wish I could find a flat or matte black labeling tape...would make the gauge face modification nearly invisible except to "those in the know"...I'll see how the gloss label looks in varying light conditions. If it doesn't blend well, I may just leave the "economy" marking alone as-is...

J.G.

Random thoughts:

1) Use the gauge cluster from a very early 190e...these weren't marked "unleaded only", so it doesn't look out of place.
2) You will need to piece together parts from the donor gauge and your gauge, because the OP gauge was mechanical on the early cars. Also the vacuum gauge requires drilling a hole in the circuit board.
3) I've set this up as an economy gauge, you can read about the conversion here:
An Economy Gauge for my 190D - Mercedes-Benz Forum
4) If you had a boost gauge, I don't understand what you would do with the information. I've set up boost gauges temporarily to diagnose a problem, but I don't know why I would need one full time.

Thanks...I found an '86 gauge for $22 bucks on ebay without the unleaded/premium unleaded notation AND HAS the economy gauge already!...pic attached. I will remove the needles on that one and then remove the gauge face plate (held on by 2 screws at the 4 and 8 o'clock positions) and swap this face to the brand new in the box '89 gauge I have on hand. (...which also has nice new bright orange needles!)

Toughest part of all this looks like it will be access to the speedo cable to remove the cluster assembly. The left ventilation duct flex pipe needs to come out to get easy access to the cable. The bugger is getting that duct back on afterwards so that it doesn't leak air at the joint!

J.G.

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I love having one, it is a nice part of the cross-check, does work as an economy gauge of sorts, wastegates do fail and stay closed (or open), and if you feel that your performance has changed it is a good reference to see if you are generating the boost that you expect. It becomes much more useful with a pyrometer/EGT gauge however even stock, which will tell you if for example your SOV is clogged and you are getting boost without enrichment.

Regarding the left vent to access the speedo cable, I have found in my 190Dt that I can pull the cluster out just enough to reach it with my fingertips and remove/install the lock ring on the cable end.

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Gone to the dark side

- Jeff

I agree entirely...the more information presented to the driver pertaining to the health of the vehicle, the better. I also installed a 16V center console gauge cluster as well. (pic attached) As an airline pilot, I'm spoiled by being able to see tons of information at a glance. I hate my W202 which doesn't even have an oil pressure gauge! (in the process of correcting that omission as well!...story to follow.)

As for the speedo cable, mine is very tight with virtually no slack and I don't want to damage anything by forcing the cluster out to reach behind it. It's a pain to pull the vent hose, but I tend to like to do things "by the book"...and just once!

J.G.

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I'm told that on the 124, possibly the 201 also as they're pretty close in many ways, there is a clip that releases the cable from the floor and allows more slack.

I too like gauges, if you have a restricted fuel filter you will have boost but no power and no EGT gain, much different from a dragging brake or other power/drag issue.

I have fitted the center panel from a W201 to my 124 also for gauges (in place of the ashtray). As yours came from a 16V, the regular W201 cars (pre-cassette holder) had a blank zebrano panel which after a date with a sharp hole-saw or forstner (sp?) bit looks good with gauges and USB outlets. A nice un-faded un-cracked one is hard to find, but if you're ever roaming a yard and see an early 201, ... grab the sucker!

Also an Audi 90 has a zebrano panel in the center console with three VDO gauges, slightly narrower but a little creativity I'm sure it would look stock.

__________________

Gone to the dark side

- Jeff

For the speedo cable, just remove the left vent, push the duct down, squeeze your hand back, and unscrewcthe cable from the cluster. Pull the cluster out a bit, but once you feel the speedo cable resisting stop and don't pull further. If you absolutely can't ram your arm far enough in, you'll have to undo the speedo cable at the trans to give you more slack. Your arm will be sore and cut up, it's normal.

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'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

I've been adding additional gauges to "information-deficient" MB's for some time...lol. I think I have a bit of a problem!

Accessory Guage Panel Installed in W210 E300 Turbodiesel!

J.G.

One hint for the lettering Letraset - Product Inforamtion : Transfer Lettering

This stuff is old school. It consists of a sheet of letters and symbols that is some sort of plastic deposited on the back side of what feels like parchment paper. You put the letter over where you want to apply it and gently rub with a pencil to transfer the letter. It takes a royally steady hand and sharp skills but you can make some really nice lettering with this stuff.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

As a former pilot, I completely concur. Here's my version of a glass panel

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

Manny is basically correct on removal procedure. You first pluck out the vent by positioning it in the center, then pulling from the center with a pair of pliers on each side. Then remove the surround with a pair of dash hooks. But if you still can't get your hand in, don't push down the vent, just pluck it out. It will be easy enough to replace. I used to do this from below, and THAT's a tough task. Unlike the 124, the cable does NOT release from the floor.