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+--- Thread: prechambers mods? (/showthread.php?tid=5643)
RE: prechambers mods? - OM616 - 12-13-2014
Something to keep in mind regarding PC Mods...
Just opening up the burn holes will improve starting ease, quiet knocking, reduce smoke, lower high RPM EGTS, and increase torque and top end power a little. I say a little because if the fuel and timing settings are not also changed to take advantage of the effect larger holes have, then you are just making the stock set up more efficient.
The true power gains come from advancing the timing DRAMATICALLY, and then Increasing the fuel.. And by Dramatically I mean advance the IP to the stops at the very least.. To really get the most out of it, you will need to pull the IP and reclock it so you have adjustment again.
The small PC holes are the limiting factor in regards to timing, the cylinder pressure gets to ignition temp way before the PC air does because of the restriction from the small holes. By opening up the holes, the PC will fill faster, and there for reach Ignition temp sooner, allowing the injection to take place sooner without knocking. Advancing the injection timing results in more torque, power, and lower EGTs. This allows you to increase the fuel even more than you could with the stock PCs and with the same boost.
If one is unable or afraid to adjust the IP and fueling to take advantage of the larger PC holes, it is best not to mess with them at all. Just my 2 cents based on doing a couple lol..
RE: prechambers mods? - barrote - 12-13-2014
Btw I finished the job today. A cobalt drill bit works nicely
[/quote]
hy, din´t i told u
. just got to ask!!!
i dont like to buy online, several times i ordered some crap and ended up the wrong crap and took me a long time to have the right crap.
post us with the results i too have my pre cups as:
inner hole to ejector head 8mm,
inside hole under the injector seat 10mm
center ejector hole 2mm
the 8 holes around 3mm
regards.
(12-13-2014, 12:28 PM)OM616 Something to keep in mind regarding PC Mods...
Just opening up the burn holes will improve starting ease, quiet knocking, reduce smoke, lower high RPM EGTS, and increase torque and top end power a little. I say a little because if the fuel and timing settings are not also changed to take advantage of the effect larger holes have, then you are just making the stock set up more efficient.
The true power gains come from advancing the timing DRAMATICALLY, and then Increasing the fuel.. And by Dramatically I mean advance the IP to the stops at the very least.. To really get the most out of it, you will need to pull the IP and reclock it so you have adjustment again.
The small PC holes are the limiting factor in regards to timing, the cylinder pressure gets to ignition temp way before the PC air does because of the restriction from the small holes. By opening up the holes, the PC will fill faster, and there for reach Ignition temp sooner, allowing the injection to take place sooner without knocking. Advancing the injection timing results in more torque, power, and lower EGTs. This allows you to increase the fuel even more than you could with the stock PCs and with the same boost.
If one is unable or afraid to adjust the IP and fueling to take advantage of the larger PC holes, it is best not to mess with them at all. Just my 2 cents based on doing a couple lol..
well the thing is i do agree with u
i have acess to a MB device with a light wich u can use to time , it takes 5 min.
although MB say to set between 14º and 16º, i´m running at 18,5º wich was found to be the best place.
once after installing the pump i had it at 21º and it run, but it was not the good place.
my question is , if u are familiar with the light device? how many degree´s are we talking about?
RE: prechambers mods? - Petar - 12-13-2014
(12-13-2014, 12:28 PM)OM616 Something to keep in mind regarding PC Mods...
Just opening up the burn holes will improve starting ease, quiet knocking, reduce smoke, lower high RPM EGTS, and increase torque and top end power a little. I say a little because if the fuel and timing settings are not also changed to take advantage of the effect larger holes have, then you are just making the stock set up more efficient.
The true power gains come from advancing the timing DRAMATICALLY, and then Increasing the fuel.. And by Dramatically I mean advance the IP to the stops at the very least.. To really get the most out of it, you will need to pull the IP and reclock it so you have adjustment again.
The small PC holes are the limiting factor in regards to timing, the cylinder pressure gets to ignition temp way before the PC air does because of the restriction from the small holes. By opening up the holes, the PC will fill faster, and there for reach Ignition temp sooner, allowing the injection to take place sooner without knocking. Advancing the injection timing results in more torque, power, and lower EGTs. This allows you to increase the fuel even more than you could with the stock PCs and with the same boost.
If one is unable or afraid to adjust the IP and fueling to take advantage of the larger PC holes, it is best not to mess with them at all. Just my 2 cents based on doing a couple lol..
What i don't understand is why has MB made the holes small in the first place
There must be something we don't know.
RE: prechambers mods? - DiseaselWeasel - 12-13-2014
Noise (retardation/prolonging of ignition?), economy, emissions(!!), longevity - what di I know!? But - keep in mind that a manufacturer may pursue other goals than we do. For a passenger vehicle engine commercially sold in high quantitys. Especially MB seems very concerned with noise emissions, I think that's why they clinched to the pre-chamber principle for so long...
RE: prechambers mods? - Tito - 12-14-2014
The knocking sound is not from the combustion. The knocking sound is from the piston hitting the other side of the cylinder under load. It actually makes sense to retard the pump. But we will see. Again, I can use a dyno for free
RE: prechambers mods? - starynovy - 12-14-2014
(12-13-2014, 05:14 PM)DiseaselWeasel Especially MB seems very concerned with noise emissions, I think that's why they clinched to the pre-chamber principle for so long...
Indeed, same with BMW which trialed M47 4 cylinder diesel engine with DI and VP44 pump. They concluded it has inferior running quality, noise and emisions, therefore unsuitable for use with 5er (E) and 7er (S) and left it for lower class 3er cars ©. So they sticked with prechamber M51 until common-rail M57 was available for mass production. Only premium car maker who didnt seem to care about tractor like noise was Audi, they came up with 1.9TDI in passenger car as soon as 1992 I believe and few years later clatering ticking and smelling (but good) AEL 5 cylinder made its way in Audi A6 (E).
RE: prechambers mods? - DiseaselWeasel - 12-14-2014
You should listen to Lancia 2.4 20V Multijet... That's the least amount of fcuks ever given
RE: prechambers mods? - sassparilla_kid - 12-14-2014
Okay so who knows a good place (in the US) to order these drill bits and/or reamers?
RE: prechambers mods? - MFSuper90 - 12-14-2014
mscdirect is where I order almost all my metal working stuff. If not, I use enco.
RE: prechambers mods? - Petar - 12-15-2014
(12-14-2014, 07:21 AM)DiseaselWeasel You should listen to Lancia 2.4 20V Multijet... That's the least amount of fcuks ever given
That's a sweet sounding 5 cylinder, reminds me of the mercedes OM612
RE: prechambers mods? - barrote - 12-15-2014
That's a sweet sounding 5 cylinder, reminds me of the mercedes OM612
[/quote]
hurgg what the problema of a 612!!! besides a weak crankshaft and rods lol . the noise is amasing , something dificult to recognise from an italian engine, i mean na italian engine!!!
even a jonh deere engine sounds better than any italian engine
That's a sweet sounding 5 cylinder, reminds me of the mercedes OM612
[/quote]
hurgg what the problema of a 612!!! besides a weak crankshaft and rods lol . the noise is amasing , something dificult to recognise from an italian engine, i mean na italian engine!!!
even a jonh deere engine sounds better than any italian engine
dont know in there , but in here any hardware store have at least HSS Cr .5 drill bits , alias cobalt drill bits. HSS Cr .8 rocks at dry cut pretty much through everithing.
RE: prechambers mods? - MTUPower - 12-27-2014
Any dyno news and consensus on the hole size to drill? I have 5 to work with. thanks all.
RE: prechambers mods? - Tito - 12-28-2014
I'm a long way from testing... The engine needs to be put together. Still need to flow the ports. Then I must try to fit the package in a w114 with hx40s and an eaton charger. My carlift is broken so that needs fixing first.
So yeah i'm sorry... But there won't be a dyno run any time soon.
RE: prechambers mods? - CRD4x4 - 12-28-2014
"even a jonh deere engine sounds better than any italian engine
"I quite like the sound of my Italian turbodiesel engine (VM Motori 2.8L)!
Its straight piped from the turbo (Garrett GT2056v) back but not near obnoxiously loud (except in a parking garages).
That being said, I can't wait to drive a 606 powered Jeep! And I'll be sure to modify the precombustion chambers!
RE: prechambers mods? - barrote - 12-30-2014
(12-28-2014, 06:17 PM)CRD4x4 "even a jonh deere engine sounds better than any italian engine
I quite like the sound of my Italian turbodiesel engine (VM Motori 2.8L)!
Its straight piped from the turbo (Garrett GT2056v) back but not near obnoxiously loud (except in a parking garages).
That being said, I can't wait to drive a 606 powered Jeep! And I'll be sure to modify the precombustion chambers!
yep, the most amasing sound in diesel engines is from the old stile caterpillars. fortunatly i haven´t seen one in a small veicle.
my 605 , sounds amazing too.
RE: prechambers mods? - MTUPower - 01-10-2015
I have five prechambers headed to the machine shop this coming week. Going to open up the three front larger holes to .150 and the back two .125 and the bottom one larger than what it is but less than .125. What is the point of opening the injector seat? Wouldn't the heat shield hole size be the limiting factor here? I can give the engine plenty of fuel with my Myna pump. I'm still running the stock turbo but have a small IC atop it which goes directly into the intake manifold. Minimal cooling compared to other set-ups but also no long piping to which increases lag. I might install the long runner intake I have but that would require a new air intake plumbing plan. Any thoughts on this plan?
RE: prechambers mods? - MTUPower - 01-12-2015
My first one is complete- on a 617-95X
Measurements in drill bits sizes. I used a "Rigid" coldfire set from a local store. The bottom hole did not fit a 5/64, I drilled it to 5/64. The back two were slightly smaller than a 3/32, I drilled them to 1/8. The front two on either side were 1/8, I drilled them to 11/64. The front center was only slightly larger than the other two at +1/8, I drilled it to 11/64. Hand drilled with the PC in a vice. The bits were new and I put whatever sized fit into the hole and positioned the PC so it was straight; (and then removed it) that way I enlarged the holes in the same orientation. No oil used. I then used a countersink to smooth the edges slightly of all the holes except the bottom. It was easier than I thought. I hope to get the other four done tomorrow and installed within a week.
RE: prechambers mods? - sassparilla_kid - 01-13-2015
Excellent let us know if there's more oomph
RE: prechambers mods? - MTUPower - 01-14-2015
My 11/32 drill bit got dull after 6 holes- I went to Lowes and bought a DeWalt DW1311 Titanium speed tip bit for maybe $4. Cut right thru the next hole with ease; five more to go. After the first the first PC I started using some oil on the drill bit, since the PC in a vice and I'm drilling by hand I don't use much oil however. I also used 220 grit emery cloth afterwards on the drilled areas to smooth the edges out.
EDIT: Ha! that drill bit cut three holes and was dull. The cobalt version of the DeWalt (DW1211) was 10 cents more and it lasted longer.
RE: prechambers mods? - MTUPower - 01-14-2015
All five complete!
RE: prechambers mods? - Eric78 - 01-15-2015
Anyone got links to a supplier of prechambers?
RE: prechambers mods? - MTUPower - 01-15-2015
(01-15-2015, 04:21 AM)Eric78 Anyone got links to a supplier of prechambers?No, but you could put a ad in the classified here and ask. The best bet is junk yard collectors.
RE: prechambers mods? - Eric78 - 01-16-2015
(01-15-2015, 09:55 AM)MTUPower(01-15-2015, 04:21 AM)Eric78 Anyone got links to a supplier of prechambers?No, but you could put a ad in the classified here and ask. The best bet is junk yard collectors.
Are prechambers from 602s & 603s compatible with 605s? Because 604, 605(only a handful of NA w202 C250s were sold here), & 606(not sure if any car fitted with this engine was sold here) engines are never found at wreckers here & even 602s & 603s are pretty thin on the ground.
RE: prechambers mods? - MTUPower - 01-16-2015
I always checked part numbers online with parts sellers to see if they were the same. If you can find a PC for a 602 and then see if the PC for a 606 is the same number then they are the same. Not many 606 or 60X engines in the yards here anymore.
RE: prechambers mods? - raysorenson - 01-16-2015
(01-16-2015, 07:09 AM)Eric78 Are prechambers from 602s & 603s compatible with 605s?
No
RE: prechambers mods? - barrote - 01-16-2015
(01-16-2015, 09:43 AM)raysorenson [quote='Eric78' pid='69189' dateline='1421410149']
Are prechambers from 602s & 603s compatible with 605s?
precups for N/A engines 604/605/606 are the same they fit all the heads,
precups for TD 604/605/606 are the same they both fit the heads
diff from 604N/A and 604TD is hole size.
601/602/603 uses diff precups not compatible with 4valve head, injector is compatible with any of them
again N/A and TD have the same diff at hole size.
good luck
RE: prechambers mods? - raidaru - 01-23-2015
MTUpower, did u install them? Any difference with the bigger holes?
RE: prechambers mods? - MTUPower - 01-24-2015
My transmission needed seals replaced and that meant it has to come down then go back up. That and the prechambers are going in now; this coming week I should give a report.
RE: prechambers mods? - led-panzer - 02-02-2015
Ill be trying this mod out as well. Going to drop by my old machine shop and borrow the mill.
Eagerly awaiting your results MTU
RE: prechambers mods? - MTUPower - 02-02-2015
[attachment=796
RE: prechambers mods? - Sleek~silver602 - 02-02-2015
I would love to see how this turns out as this would be a good addition to pulling the head and porting. Ill be picking up the 190K 98 E300TD this week. It will stay stock for a while but then the fun will come.
RE: prechambers mods? - MTUPower - 02-03-2015
(02-02-2015, 08:34 PM)Sleek~silver602 I would love to see how this turns out as this would be a good addition to pulling the head and porting. Ill be picking up the 190K 98 E300TD this week. It will stay stock for a while but then the fun will come.FWIW Someone previously reported porting the head on a MB diesel resulted in less than a 5% gain in HP and was not worth it IIRC.
RE: prechambers mods? - MTUPower - 02-06-2015
Well the work is done with the prechamber mods and the end result is just short of "WOW!" I did not change the timing as it was already advanced so there is perhaps some room there for future gains. Now for the report after 40 miles: not as much low end increase as I thought, but there was improvement from idle to 1500 rpm; maybe 5%. It did climb thru the rpm range to get to 2000 RPM measurably faster- and from 2000-3000 the power difference is very noticeable. There was a perhaps 80% decrease in smoke at all rpms except idle where there was and is just a slight bit. That is ultimately important because I have a MYNA pump and it's turned low due to too much smoke for a daily driver when I get on it. Now I can turn the pump up and the car ought to really fly. The 2000+ rpm response is instant and stronger. It really makes a difference at the mid and top end by seeming to breathe freely. The engine is louder and sounds more like a Cummins, but I'm very happy. I certainly cannot say what the long term effect is on enlarging the PC holes, but the short term result is "oh yeah!" I'm going to sleep tonight with a big smile- I think this was a very good mod.
More testing, videos and minor tweaks to come soon...
RE: prechambers mods? - OM616 - 02-07-2015
If you are open to tuning suggestions.. I would recommend that before you turn up the max fuel, that you instead turn up the Torque Control, but I have no idea on a M pump how to balance the Idle out. Once you have the Torque Control as far as you can, and you still want more fuel, then that is the time to increase the max delivery, IMOP.
Also, advancing the timing will increase the bottom end, as well as the wrest of the curve. Depending on the condition of the engine (compression) and quality of the injection, (how fine a fuel mist or if your nozzles are like a garden hose) you will be able to advance the injection timing farther than the stock prechambers would allow, providing that the compression and injection are good.
RE: prechambers mods? - MTUPower - 02-07-2015
(02-07-2015, 11:57 AM)OM616 If you are open to tuning suggestions.. I would recommend that before you turn up the max fuel, that you instead turn up the Torque Control, but I have no idea on a M pump how to balance the Idle out. Once you have the Torque Control as far as you can, and you still want more fuel, then that is the time to increase the max delivery, IMOP.Always open to suggestions! However I am not messing with the Myna pump TQ settings. The max fuel is an external setting as is fuel/boost setting; both of which are easy to adjust and return to without fear of upsetting a balance. The trick is to get it set so that I get maximum power with as little smoke as possible. I think I've done that with 5 adjustments and runs earlier today. I can set full fuel at no boost and smoke out the neighborhood or minimum fuel and no smoke at all and be very much slower. Of course my right foot also has it's role, but I want as super power and no smoke- don't we all? My previous MW pump was altered extensively and was awesomely set for a stock internals MW pump.
Also, advancing the timing will increase the bottom end, as well as the wrest of the curve. Depending on the condition of the engine (compression) and quality of the injection, (how fine a fuel mist or if your nozzles are like a garden hose) you will be able to advance the injection timing farther than the stock prechambers would allow, providing that the compression and injection are good.
RE: prechambers mods? - led-panzer - 02-07-2015
(02-06-2015, 11:48 PM)MTUPower Well the work is done with the prechamber mods and the end result is just short of "WOW!" I did not change the timing as it was already advanced so there is perhaps some room there for future gains. Now for the report after 40 miles: not as much low end increase as I thought, but there was improvement from idle to 1500 rpm; maybe 5%. It did climb thru the rpm range to get to 2000 RPM measurably faster- and from 2000-3000 the power difference is very noticeable. There was a perhaps 80% decrease in smoke at all rpms except idle where there was and is just a slight bit. That is ultimately important because I have a MYNA pump and it's turned low due to too much smoke for a daily driver when I get on it. Now I can turn the pump up and the car ought to really fly. The 2000+ rpm response is instant and stronger. It really makes a difference at the mid and top end by seeming to breathe freely. The engine is louder and sounds more like a Cummins, but I'm very happy. I certainly cannot say what the long term effect is on enlarging the PC holes, but the short term result is "oh yeah!" I'm going to sleep tonight with a big smile- I think this was a very good mod.
More testing, videos and minor tweaks to come soon...
This is very encouraging, and great news. Thank you for posting your results! Now you just need to get rid of that ancient paddlewheel - uh, I mean - stock turbo
I'll be drilling and reaming mine soon hopefully. Although I won't be able to drive the car for another couple months (snow). My plan will be a 25% enlargement of all holes. Already starting with the "uprated" '85 prechambers with the larger injector hole and lower seat.
RE: prechambers mods? - MTUPower - 02-07-2015
(02-07-2015, 09:36 PM)led-panzer This is very encouraging, and great news. Thank you for posting your results! Now you just need to get rid of that ancient paddlewheel - uh, I mean - stock turboI don't think the % view of how much you are going to enlarge the holes is practical because common drill bits don't come in those sizes. That's why I choose the sizes I did; I could buy the drill bits. I'll post a video of the engine running so folks can listen to the sound. My indie, my self and my neighbors all think it sounds like a 4X4 truck now- not that that is bad. The turbo whistles more than before, which I like. It's not too loud by any means. I still have to monitor how I drive so I don't give it full throttle near the 2/3 or 3/4 shifts as it flares. I don't think there is much to be done about this- just gotta live with it. The 1/2 is fine.
I'll be drilling and reaming mine soon hopefully. Although I won't be able to drive the car for another couple months (snow). My plan will be a 25% enlargement of all holes. Already starting with the "uprated" '85 prechambers with the larger injector hole and lower seat.
Yes the turbo replacement is in the works, but with it come a new exhaust and intercooler system- unless the turbo is the same size, in which case I'll just change the exhaust to a larger size; it's still stock minus the rear muffler.
While this prechamber were installed the tranny came down and was re-sealed with new orings and a new front pump. That was pricey.
RE: prechambers mods? - DiseaselWeasel - 02-08-2015
Did you measure 0-60 times, 30-60 times etc.? Resp. is there objective data from before/after the pre-chamber drillings? A "feels faster" can be all or nothing but imagination.
Oh dear - I'm not doubting your effort, please. It's just in my kraut nature to strive for exact data & precision, you know what I mean? Only hard facts satisfy my little german soul 
And you know what? I love the harsher sound of truck etc. engines! MB engines are much too soft. But then perhaps this was the main goal and reason to keep the pr-chamber technology for such a long time. To make the diesel go uptown, keep it quiet and manered, do away with it's tractor image. And maybe this is - who knows? - why they made those holes so smal. Probably was for emissions (smoke is not the only variable in diesel exhaust emissions) too.
All in all - I'm interested in this! If there's something to gain and make that sluggish engine a bit more reactive
The only long-term concern I might have is stress to the pre-chamber. With holes too big the tip of the chamber may not conduct heat quickly enough. And is under higher thermal stress (see p.e. here )... Respectively; I'd fear the tip may fall off if the engine runs "hot". Do you monitor your EGTs, MTUpower? I think this would be very interesting too as a before/after. If or how they have changed
Don't mind me, just thinking out loud... And as said, not doubting your or anyones effort!!! I just want to know stuff as precisly as possible
I tend to make science out of everything. So I'm not euphoric but always a bit doubtfull.
RE: prechambers mods? - led-panzer - 02-08-2015
You can get drills and reamers in almost any size. Just not at Lowes.
RE: prechambers mods? - MTUPower - 02-08-2015
I think today might be the 0-60 time trials day; I too have a healthy skepticism of mods without quantifiable data. I don't have the money for a dyno run; I need a better paddle wheel, exhaust and different IC/intake system first. My EGT's seem lower, the most I saw with the off boost fuel at max in a hard (short) run was 1150- and it went immediately right back down. Max boost at that setting was around 22. With the off boost fuel at minimum max boost was around 13. I didn't look at egt's. Settings now are seeing boost around 16 and some grey smoke when my right foot wants.
The first machine shop I went to I had a conversation with the owner and he turned me down for the job (and so did the second one- which is why I did it myself) and told me he didn't have all the drill bit I'd need. I did the job on the boat I captain with my personal 110v hand drill. I don't have a vice at home but I do on the boat. Get'er dun. I could have gone and bought exact sizes for a % increase in hole size but after thinking about it and the stories of using multiple drill bits and understanding this is still an emerging field I just used what was available. I think if we had multiple sets of PC's with different hole sizes that could be swapped in and out as the only variable we'd find out more info on what would work best for our applications. Special order sizes after quantifiable results which are repeatable ought to become the norm- we are not there yet is my thinking. Move this meme forward folks and improve!
RE: prechambers mods? - barrote - 02-08-2015
MTU wich engine is yours? and what size hole did u used?
i have a set of prechambers for 605 drilled at 3mm the 8 around holes and 2mm at the center one. since i dont have all the tools, it takes me some more time than expected. so still on the box.
i´ll post my results.
regards
RE: prechambers mods? - led-panzer - 02-08-2015
Here is my theory.
Stock Holes:
Middle hole = .132
Either side of middle hole = .120
Back holes = .092
Bottom hole = .078
The area of all stock holes = .05432
25% Enlargement:
Middle hole = .165
Ether side of middle hole = .150
Back holes = .115
Bottom hole = .097
The area of 25% enlarged holes = .08483
The area of the 8mm burn tube = .07787
By exceeding the area of the burn tube, you've eliminated the holes as a restriction, because they flow more than the burn tube.
Of course you've achieved the same thing. And it seems it works to great effect. My theory of increasing the hole size but keeping the hole sizes still proportional to each other is to hopefully preserve whatever flow pattern or swirl that mercedes was trying to achieve.
RE: prechambers mods? - raidaru - 02-08-2015
(02-07-2015, 05:58 PM)MTUPower(02-07-2015, 11:57 AM)OM616 If you are open to tuning suggestions.. I would recommend that before you turn up the max fuel, that you instead turn up the Torque Control, but I have no idea on a M pump how to balance the Idle out. Once you have the Torque Control as far as you can, and you still want more fuel, then that is the time to increase the max delivery, IMOP.Always open to suggestions! However I am not messing with the Myna pump TQ settings. The max fuel is an external setting as is fuel/boost setting; both of which are easy to adjust and return to without fear of upsetting a balance. The trick is to get it set so that I get maximum power with as little smoke as possible. I think I've done that with 5 adjustments and runs earlier today. I can set full fuel at no boost and smoke out the neighborhood or minimum fuel and no smoke at all and be very much slower. Of course my right foot also has it's role, but I want as super power and no smoke- don't we all? My previous MW pump was altered extensively and was awesomely set for a stock internals MW pump.
Also, advancing the timing will increase the bottom end, as well as the wrest of the curve. Depending on the condition of the engine (compression) and quality of the injection, (how fine a fuel mist or if your nozzles are like a garden hose) you will be able to advance the injection timing farther than the stock prechambers would allow, providing that the compression and injection are good.
u can try some water/methanol injection, meth should help build up boost without smoke, preferably with the EGT failsafe system
RE: prechambers mods? - MTUPower - 02-08-2015
(02-08-2015, 09:55 AM)barrote MTU wich engine is yours? and what size hole did u used?I have an OM 617-952 in a 1984 300TD and the OM648 in a 2005 E320 CDI. This was for the 617.
i have a set of prechambers for 605 drilled at 3mm the 8 around holes and 2mm at the center one. since i dont have all the tools, it takes me some more time than expected. so still on the box.
i´ll post my results.
regards
(02-08-2015, 11:08 AM)led-panzer Here is my theory.Were you able to fit the 5/64's drill bit into your bottom hole? I could not and that's what I drilled it with. Otherwise you are saying you are going to enlarge them less than what I did, save the bottom hole. I also enlarged all three front holes to the same size. My total is .8411- slightly less than your plan, due to your larger bottom hole. I could fit a 1/8 into the two "front" holes- which makes them .125.
Stock Holes:
Middle hole = .132
Either side of middle hole = .120
Back holes = .092
Bottom hole = .078
The area of all stock holes = .05432
25% Enlargement:
Middle hole = .165
Ether side of middle hole = .150
Back holes = .115
Bottom hole = .097
The area of 25% enlarged holes = .08483
The area of the 8mm burn tube = .07787
By exceeding the area of the burn tube, you've eliminated the holes as a restriction, because they flow more than the burn tube.
Of course you've achieved the same thing. And it seems it works to great effect. My theory of increasing the hole size but keeping the hole sizes still proportional to each other is to hopefully preserve whatever flow pattern or swirl that mercedes was trying to achieve.
Water/methanol injection is also on the list of future mods....
RE: prechambers mods? - MTUPower - 02-09-2015
I have not had the chance to do some 0-60 runs, but did have some 60-90mph full throttle runs- but I was driving alone. No times and no video as I won't be driving that fast while working the iphone. I sure do get to 90 awfully quick. Boost was as high as 19 and EGT's to 1250 briefly, then back down to 650 where they were pegged while doing 70 mph. This is while the fuel setting is still not on full. I'll see what EGT's are at 75 tomorrow while cruising- but I don't like to cruise at 80- I don't want the ticket.
RE: prechambers mods? - MTUPower - 02-10-2015
0-60 mph test runs averaged just under 9 seconds. Held the brakes until about 2000. First run easily spun the rear tires which was new. Video posting to come. Far less smoke than previous full fuel runs; but that might be due to my better launching technique. I don't think previously I held the brakes till 2K. I downloaded a iphone Horsepower app "pocket dyno"- I couldn't get it to work by myself.
Here's a online calculator:
http://www.060calculator.com/
If the car weighs 3700 then it's about 172 HP. If it's 3800 then about 177. 3600 is 168 HP
http://www.autosnout.com/0-60-Calculator.php
this one says at 3800 pounds it's 185 HP and at the other weights it's slightly higher than the first.
https://www.youtube.com/watch?v=aYchWa4wN2E&feature=youtu.be
RE: prechambers mods? - turbojeep - 02-10-2015
So would you say its worth the effort to do? Spinning tires sound like a huge improvement. All in all sounds like you've gained a bit, I'm a believer in it.
Too bad you didn't run one of those app before you drilled though, that would have been good to see.
RE: prechambers mods? - MTUPower - 02-10-2015
(02-10-2015, 09:26 PM)turbojeep So would you say its worth the effort to do? Spinning tires sound like a huge improvement. All in all sounds like you've gained a bit, I'm a believer in it.
Too bad you didn't run one of those app before you drilled though, that would have been good to see.
Here's my when the Myna pump was first installed with stock prechambers, no other variables save two more kids in the car- maybe another 100 pounds.
https://www.youtube.com/watch?v=s3BxPei7yXU
https://www.youtube.com/watch?v=B57QNA-XYlo
0-60 was closer to 9.5 seconds and way more smoke.
RE: prechambers mods? - barrote - 02-16-2015
hello fine people,
unfortunately i can´t reporn any gains with a increased hole pre cup. this was for a 605 engine.at least a large increase did not work for me.
i´ll post a thread about the subject once i got some time to gather the changes made.
regards.
RE: prechambers mods? - MTUPower - 02-16-2015
(02-16-2015, 03:12 PM)barrote hello fine people,
at least a large increase did not work for me.
i´ll post a thread about the subject once i got some time to gather the changes made.
regards.
Do you have a IP which is modified? How about the rest of your engines systems? What is your max boost? How much increase was it - and what size were the holes to start with and what did they end up at? Do you have pics?