MyE28.com

I have the Carbtune if you guys are interested in possibly setting up a borrow program. I used bought it and used a few years back to sync the throttle bodies on my 1993 M5. It was a little tricky at first, but I was able to get mine spot on perfect, and my car ran amazingly smooth and strong afterwards. I do remember noticing gas mileage well into the mid 20's after this was done. At the same time I adjusted my valves, and cleaned my MAF with cleaner. These added up to a big difference.

I had a chance to repackage the Mantis-Manometer into a shippable tool by removing the 1x6 board and mounting it to a 4' straight edge. The official Mantis-Manometer Gen II is now available for borrowing!




It works just like before. There are small cotter pins located every 12 inches to allow it to fold into a flat rate box.




Here is a very short video of the tool in use.
https://youtu.be/P5Z5fYuUjy4

And a full set of assembly and set up instructions are included below and properly formatted, printed and in the box.



I do have several folks that would like to borrow the Mantis-Manometer, so I think it is most prudent to require a small deposit on top of the shipping costs. I am assuming it will be $15.00 to ship. I would like a $50 deposit, which I will return $45.00 (paypal and misc). So, if you are still interested at this stage, I will be asking $15.00 to ship plus $50.00 for a deposit for a total of $65.00.

I am thinking this will encourage folks to return it quickly, so others can share.

The better option is to come by, hang out and have a beer, or invite the Mantis-Manometer and owner to a local S38 tune day:)

Thank you for everyone's contribution to this project.

Fun,fun,

Dean

PS: If I can figure out how to link a .pdf, below you would see the instructions, pretty formatting, a cool logo and nice text...

------------------------------------------------------------------------------------------------------------------------------
You are borrowing the new Mantis-Manometer designed to balance the individual throttle bodies found on the BMW S38.
Please note how it was packed, as you will be repacking it in the same manner, and returning it Dean.
The kit consists of:
1. 100’ of tubing connected to a common manifold, backbone structure and integrated vacuum gauge
2. Set of six stopper plugs
3. Large syringe (hopefully not needed)
4. Marvel Mystery Oil (also, hopefully not needed)
To ASSEMBLE the Mantis-Manometer:
1. Carefully remove and untangle the meter.
2. Lay the meter on the floor and insert the cotter pins which are attached to vacuum gauge line. Don’t bother to bend the cotter pins. The gauge will stay together. It is now assembled.
3. Hang the Mantis-Manometer from a hook in the garage.
4. Position the ends of the vacuum hoses above the vacuum gauge. If the fluid is anywhere but below the vacuum gauge, you will need to help draw it back down by lifting the ends of the tubes.
5. Remove the six stopper plugs. This will allow the oil to drain back into the manifold.
6. If air bubbles are present in the tubes, you can suck on the tubes to draw the fluid up slightly and this releases the trapped air.
7. Once all six tubes are reasonably level, remove the end cap on the vacuum gauge. This will allow the gauge tube to settle out and finish the tube balancing. REINSTALL THE SINGLE VACUUM CAP, or you will draw all the Marvel Oil into your motor.
8. If you need to add fluid (unlikely), use the syringe and port near the vacuum gauge. Add fluid up to the adapter connection (large to small clear tubing) level at rest. It is normal for fluid to be drawn down from this tube during operation, but not “lost”.
9. You are now ready to connect the legs of the Mantis-Manometer to your S38 ITB ports.
To USE the Mantis-Manometer:
1. Connect all six legs of the Mantis-Manometer to your intake ports. All six hoses must be connected before starting the engine, or you will draw all the Marvel Oil into your motor.
2. Adjust the bypass screws until the fluid levels are approximately even
3. Do not adjust when the engine is cold.
4. You will see each intake pulse in the tubes. They will rise and fall roughly ½ inch. This is normal – Adjust until all six tubes are within a one inch band.
To RETURN the Mantis-Manometer:
1. Ensure all six legs of the Mantis-Manometer and the vacuum port are plugged.
2. Either reuse the large flat rate box that it was sent in, or locate another one. Do not kink the tubes.
3. Enjoy your newly balanced motor. Take photos. Post to the thread. Suggest improvements. Provide comments.
4. Send the tracking number to HealeyBN7@yahoo.com.
5. When the box is received, I will refund your deposit
Thank you, Dean

Dean, love the sticker. I'm a little way away from being ready to undertake this. Critical to the balancing procedure is correctly adjusted valves, which is a bit of a black art since most of us are going somewhere between .012 and .014 depending on which shims give the closest gap to spec. I suppose that's one of the things that balancing addresses. In addition, setting up the butterflies and linkage mechanism is another important step before attempting to balance the bypass ports. Any plans to add this equipment to the kit/instructions? I can host a .pdf file for you if you want to include it in the thread.

Finally, I would recommend ordering parts number 14 (o-rings) and 16 (blue caps) ahead of time. Compromised o-rings can invalidate the adjustments.

ahab wrote:Dean, love the sticker. I'm a little way away from being ready to undertake this. Critical to the balancing procedure is correctly adjusted valves, which is a bit of a black art since most of us are going somewhere between .012 and .014 depending on which shims give the closest gap to spec. I suppose that's one of the things that balancing addresses. In addition, setting up the butterflies and linkage mechanism is another important step before attempting to balance the bypass ports. Any plans to add this equipment to the kit/instructions? I can host a .pdf file for you if you want to include it in the thread.

Finally, I would recommend ordering parts number 14 (o-rings) and 16 (blue caps) ahead of time. Compromised o-rings can invalidate the adjustments.

Those are great ideas. I agree that we should include prerequisite tuning guides/instructions to cover the valve adjustment and mechanical linkage.

My technique uses 12" metric feeler gauges from McMaster and the "difference" spreadsheet to select the correct shims. I modified the spreadsheet a bit with some excel tricks so you can quickly see which valves need attention and which are in spec. I would be happy to share my version of the spreadsheet, but I am partial to the shim bucket tool, pick and shim set:). I had to add material to the shim tool (welding to the inside of hook) and some grinding to get it to perform properly.

Agree that we should cover is the mechanical linkage, especially since I found the BMW book method to introduce errors as you reattach the linkage. I used a Chinese dial indicator and modified a standoff post to allow repositioning on the throttle bodies. If it is needed, I could include this in the kit. I'll have a little time to work on the instructions later today/tomorrow. If I can send you the .pdf, for hosting and reviewing that would be great!

The blue caps always looked out of place to me, so I left them off. It's hard to imagine a villain sneaking into the garage, opening the hood and adjusting the bypass ports...

I didn't replace the orings - ugh, but I see I have this size on the workbench. Another excuse to use the Mantis-Manometer .

All the credit for the name/logo goes to you!

Dean

First off, great idea and execution! I've still got a few things I need to check off the list before I get to balancing the throttles, but I know how I'm going to do it when the time comes.

I do have another question that I don't think has been addressed in the thread yet. Referencing the RealOEM diagram above, what is the function of the larger brass plug (#33) ? Is there a proper method for adjusting this? While ordering the O-rings for the individual plungers it seems like it might be a good idea to go ahead and refresh/adjust this larger one as well.

I would love to. I'm in the neighborhood!

HealeyBN7 wrote:
Agree that we should cover is the mechanical linkage, especially since I found the BMW book method introduces errors as you reattach the linkage. I used a Chinese dial indicator and modified a standoff post to allow repositioning on the throttle bodies. If it is needed, I could include this in the kit. I'll have a little time to work on the instructions later today/tomorrow. If I can send you the .pdf, for hosting and reviewing that would be great!

Dean

I pulled together my thoughts on the mechanical linkage adjustment and updated the .pdf. I am including a dial indicator, stand off boss and TPS bridge. The kit is heading out for the first time this weekend to Michael - macsm5 in No.Cal. Yeah.

If anyone wants to review the instructions, I can send the pdf via email.

Dean

I would not mind seeing your instructions and might have some ideas to include. Did you resolve the question of getting the on/off idle (TPS control) transition just right? I'm not sure I've seen a good procedure or target for this or I've missed it. I just unplug the TPS and adjust the big idle bypass screw to raise the rpm 100-200. But if the screw is too far open or closed and can't do this it means the base throttle setting isn't right. On an M30 that's easy as pie to fix but not so much on the ITB's. I'm due to do a valve adjustment and go back through mine again soon and plan to sort this one aspect out. Would like to see one full set of instructions that cover all the little details from valve adjustment through balance. I've been using a few different sources and my own interpretation.

Another example is the 'best' valve shim gap. I've used 'spec' on the intake but slightly more open on the exhaust per some of the experts. Is that still the consensus?

Another thing might be the AFM bypass screw setting? Closer to rich... or lean... or anywhere in between so that the computer will still dither? For example if you intentionally drive it rich so that it cannot dither the idle feels smoother but probably not best.

Lately my car has sometimes had longer cranking time before firing. It might be fuel pressure which I need to check or it could be back to this base throttle setting business. I think that and ICV home position effects this also when it is stone cold which is when it does this.

While I may never rent your tool (I'll use my own double and move back and force or build a Mantis style) I am very thankful for reads like this and thinking this is the best S38 related tech thread in a while.

Regardless of the little quirks, what wonderful motors these are and interesting for those who enjoy the tuning and tinkering. I've just been driving my S38 6er after having set most of the winter and while there are a few things to sort out it's one of the most captivating cars I've ever driven.

Sorry for the long winded reply.

PM me with your email and I'll send the document. It would be great if we had a comprehensive best practices paper on the subject!

Dean

Thanks to ahab, the Mantis-Manometer instructions are hosted here...

Instructions for Use

The kit comes with a printed copy of the instructions and the return address.

Please let me know if you anything that is not clear or needs improvement.

Dean

ahab wrote:Dean, love the sticker. I'm a little way away from being ready to undertake this. Critical to the balancing procedure is correctly adjusted valves, which is a bit of a black art since most of us are going somewhere between .012 and .014 depending on which shims give the closest gap to spec. I suppose that's one of the things that balancing addresses. In addition, setting up the butterflies and linkage mechanism is another important step before attempting to balance the bypass ports. Any plans to add this equipment to the kit/instructions? I can host a .pdf file for you if you want to include it in the thread.

Finally, I would recommend ordering parts number 14 (o-rings) and 16 (blue caps) ahead of time. Compromised o-rings can invalidate the adjustments.

Hi Dean,

In your instructions re: mechanically synchronizing the throttles, you mention to replace the o-ring in the main idle adjuster, in the RealOEM diagram AHAB posted is the main idle adjuster part number 33 and the main idle adjuster "o" ring to replace number 34?

Thanks!

ahab wrote:Dean, love the sticker. I'm a little way away from being ready to undertake this. Critical to the balancing procedure is correctly adjusted valves, which is a bit of a black art since most of us are going somewhere between .012 and .014 depending on which shims give the closest gap to spec. I suppose that's one of the things that balancing addresses. In addition, setting up the butterflies and linkage mechanism is another important step before attempting to balance the bypass ports. Any plans to add this equipment to the kit/instructions? I can host a .pdf file for you if you want to include it in the thread.

Finally, I would recommend ordering parts number 14 (o-rings) and 16 (blue caps) ahead of time. Compromised o-rings can invalidate the adjustments.

Hi Dean,

In your instructions re: mechanically synchronizing the throttles, you mention to replace the o-ring in the main idle adjuster, in the RealOEM diagram AHAB posted is the main idle adjuster part number 33 and the main idle adjuster "o" ring to replace number 34?

Thanks!

Michael,

Yes. That is correct. The main idle adjustment is the big screw or part number 33 and the o-ring is 34 (11631271346). For some reason, BMW Real OEM didn't list the size of this o-ring as they have for others, but you may be able to match it if you have access to an assortment.

Good luck and let us know how it goes!

Dean

Mantis whereabouts...

Currently it is on loan to Michael (macsm5) - NoCal - Expected return May 4-5.

Brad (bdalessio) is next on the list - NoCal

Then Eric (ronin) - Spartanburg, South Carolina

Once it is back in SoCal after Eric, perhaps we can schedule in the local sessions.

Sound fair?

Let me know if I missed anyone.

Dean

Well....I wasn't planning on making another Mantis, but this copy is going to Brad. Thank you Brad!



It has a few improvements:

This version uses nylon barbs on a larger 7 vs 6 port manifold. The larger manifold eliminates 90 degree fittings. The nylon barbs provide a better seal to the vinyl tubing and eliminate the wire ties. I also added thicker (by 1mm OD) high temperature silicone hose to the ends of the vacuum tubes. I think this is a necessary improvement to ensure the business end doesn't deform from heat.

There is also a machined aluminum barb fitting on the large hose. I had to make this one in the lathe as I could not find a 3/16 to 3/8 reducer barb.





It was a good exercise to see how much it cost to make and how much time it takes - too much of both.

Brad should get his Mantis by the end of the week. Eric - I guess you will be next in for the rental as soon as Michael and Brad are finished.

Dean

If you are talking to me, Eric, then just let me know. If you meant a different Eric, that is ok, just let me know where I fit in the schedule. The new and improved version sounds nice. Looking forward to it.

Take care,

Eric

FYI - The Manometer Kit It is on the road again for a quick loan to David as MinneapM635 in Minneapolis. Should be back and available in a couple weeks.

By the way, shipping seems to have gone up to $20 with insurance. sorry.

Dean

What an incredibly fantastic thread. This information is invaluable and will prove to be a cornerstone of mine once this ITB'd M30 is off the ground. Dean, I would be very much appreciative if you would allow me to replicate your design for my own uses as despite my eagerness, international shipping on a borrowed part is folly. Failing that, if you could perhaps be swayed into manufacturing another that would be even more excellent as I'll be needing this tool in due time, and it would be highly useful to those local S38 owners in the click. You'd have to be sure to install the ruler upside down, though.

I may have a wait until I retire to make another one, but in the mean time feel free to knock off a copy for you and your friends down under. I am thinking that you should be able to figure out all the bits by looking at the pictures. If you need something special let me know. When I put together the second kit for Brad I was shocked how quickly the parts totaled to more then a couple hundred dollars. You of course could save some money of you reused your personal fuel pressure gauge and dial indicator, but be aware that buying the fittings in small quantities is just not frugal.

It is a fun weekend project - get to it!

Dean

Got the Mantis on Monday and immediately plugged it in to get a baseline of where I was at. Last time I synched the throttles was probably 2013 and I used a single mechanical gauge and with all the pulsing, and pinching of the lines, it probably wasn't the best. Here's a video of the readings without any adjustment. Warning, I am a novice at taking and posting videos online... AND keeping my garage tidy.

https://youtu.be/KXkaAa2kSFo

A few quick adjustments and the result:

https://youtu.be/hnNzKgXWEpI

This was without any of the prerequisite "remove the screws, replace o-rings, bottom out and turn out 1 turn" baseline adjustment. So, I set off to do just that last night and wouldn't you know, the o-ring on the idle speed adjustment screw basically disintegrated upon removal of the screw. So, replacement rings ordered on fast shipment. I hope to have the Mantis back in the mail by Monday/Tuesday next week.

Dean, I give credit to you for the tool in the description of the videos. Let me know if you would like me to remove or add any other information. Want to make sure you get the appropriate credit for this great tool.

Thanks,
Dave

Thanks for the feedback Dave. Looks like you mastered it in short order and the results look great.

It doesn't fix all S38 problems (TPS actuation, ICV response, worn linkage or misalignments, valve clearances, etc), but if the basics are already covered, after tuning, the car should idle a bit more smoothly and if need be you can replace the rotten o-rings or any of the worn ITB components and re-tune to return to a stable flow.

Nice job on the videos! Thanks for linking them to the forum.

Dean

Hey Dean,

Fairly new to this board and the S38 world. Got the valves adjusted, new cap, new TPS, etc. Still idles rough and down on power. On to throttle syncing. Still loaning out the Mantimanometer? Would love to use it!

Also, when adjusting the butterfly closing gap, does the .01 refer to .01 in or .01 mm? I'm hoping inches otherwise the dial gauge i have doesn't read that fine!

Thanks!

Hello Alim!

So sorry we never got to meet in Santa Fe, but I will be back next summer.

Have you checked all the following baseline items:

-Coolant Temp Sensor
-Correct Spark plugs (gapped properly)
-Crankshaft/RPM sensor
-Fuel Pressure Regulator
-Oxygen Sensor
-Check for any vacuum leaks?


all best,
Jeff

Hey Jeff,

Next summer for sure!

Replaced Coolant Temp Sensor, Spark Plugs, and O2 sensor. Checked Crankshaft and Camshaft sensors, as well as FPR. I think I got most of the vacuum leaks. I can read 8 - 9 inHg of vacuum from the EGR port, so I think I should be ok there.

Comes down to AFM and/or throttle bodies now. Actually, I wish I could've swapped AFM's with you to see if that was the culprit. I will probably just do the MAF conversion now, though. I've only heard great things about it.

alim_h wrote:Hey Dean,

Fairly new to this board and the S38 world. Got the valves adjusted, new cap, new TPS, etc. Still idles rough and down on power. On to throttle syncing. Still loaning out the Mantimanometer? Would love to use it!

Also, when adjusting the butterfly closing gap, does the .01 refer to .01 in or .01 mm? I'm hoping inches otherwise the dial gauge i have doesn't read that fine!

Thanks!

I would be happy to lend it to you. The gap is measured in inches.

Since you say that you are down on power, In don't think balancing the ITBs will make much difference. It could help with idle smoothness and transition off idle issues, but once the butterfies are partially cracked the bypass screws are no longer in play and any performance issues would come from somewhere else.

Before you balance the ITBs you should make sure your valves are properly adjusted. If you plan on doing that later it will impact the ITB adjustments.

Let me know when you want it sent over. We will need to exchange emails off line so you can paypal me for shipping and a small deposit. Also, if you don't need the dial indicator, all the better. Turns out it is now the only one I have:)

Dean

HealeyBN7 wrote:

Since you say that you are down on power, In don't think balancing the ITBs will make much difference. It could help with idle smoothness and transition off idle issues, but once the butterfies are partially cracked the bypass screws are no longer in play and any performance issues would come from somewhere else.



Dean

HealeyBN7 wrote:I reset the OBC MPG tracker before heading out to work this morning. 80 mile round trip. Mostly 80 MPH freeway on the way into work. Traffic on the way home. I haven't see this average before, except in the wife's '84 528e.

Now that's a measurable improvement even on crappy California summer gas blend.

Dean

So what you are saying is that this was due to a difference in your driving style and not your throttle adjustment, sounds misleading.

Nanajoth wrote:

HealeyBN7 wrote:

Since you say that you are down on power, In don't think balancing the ITBs will make much difference. It could help with idle smoothness and transition off idle issues, but once the butterfies are partially cracked the bypass screws are no longer in play and any performance issues would come from somewhere else.



Dean

HealeyBN7 wrote:I reset the OBC MPG tracker before heading out to work this morning. 80 mile round trip. Mostly 80 MPH freeway on the way into work. Traffic on the way home. I haven't see this average before, except in the wife's '84 528e.

Now that's a measurable improvement even on crappy California summer gas blend.

Dean

So what you are saying is that this was due to a difference in your driving style and not your throttle adjustment, sounds misleading.

You are kidding, right? You took two sentences from this thread separated by seven months and re-ordered them, one as a self report, and the other in response to helping a fellow M5 owner that has an AFM issue and you drew the conclusion that I am trying to be misleading???

If there is something amiss about the process, method or tools described for balancing the ITBs please do share.

Dean

I am curious as to how you gained the extra MPG when you stated that adjusting the ITBs will not help you as far as performance goes and the bypass screws are no longer involved. It looks misleading when you state in the beginning of the thread that you gained all sorts of mileage and compare it to a 528e, then down the road say that this process will not help with performance issues. There is nothing wrong with your adjustment process.

Nanajoth wrote:I am curious as to how you gained the extra MPG when you stated that adjusting the ITBs will not help you as far as performance goes and the bypass screws are no longer involved. It looks misleading when you state in the beginning of the thread that you gained all sorts of mileage and compare it to a 528e, then down the road say that this process will not help with performance issues. There is nothing wrong with your adjustment process.

I think the problem is confusion by the term "performance". I equate performance with power, torque and acceleration, not on idle or off idle efficiency/mileage. See if this helps.

On my M5 the ITBs were fairly far out of adjustment (both the butterflies and the bypass screws). The car struggled (surged) at very low freeway speeds and the ECU/LM2 indicated that it was hunting (...wasting gas). Returning the ITBs to their proper synchronization allowed for much smoother light throttle drive-ability and the resulting "OBC" mileage under ideal conditions. Unfortunately, I don't drive that way most of the time, but you could. If you have an S38 and use the right pedal then you know they are capable of returning you to the filling station in quick order. My mileage has been averaging 18.5-19.5.

The purpose of this thread was not to improve S38 mileage. That was just an observation to demonstrate that the ITBs are no longer "fighting" with each other. I was looking for a repeatable way to adjust the ITBs for on idle smoothness and help with an off idle transition step. The book method of moving the vacuum gauge from port to port was not returning repeatable results.

Regarding Alim's car, he is describing "performance issues" across the power band. Adjusting the ITBs at idle or just off idle really won't have any impact at all at full or part throttle. In off line discussions with Alim it sounds like he may have a bad AFM. I offered to loan him my spare AFM for testing. I recommended that he find the root cause of the "low on power" issue first before investing the in the time to fine tune the ITBs.

Dean

That makes sense, thank you for clarifying.