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emlmcb
Veteran
Date registered: Dec 2006
Location: Buenos Aires, Argentina
Vehicle(s): 1986 LWB 300GD / 1998 E320 / 1996 LWB G300TD
Posts: 119
| POWER INCREASE FOR 617 ENGINE
Some months ago, upon joining this forum and under the title of MORE POWER FOR 617 I posted my question as what to do to get more power for my recently bought 1986 300GD.
I do thank all those who took the time to contribute their ideas, all of them were of much help and were throroughly considered.
I have some experience in adding a turbo to other vehicles I own or owned, so I was quite enthusiastic about this alternative at the begining.
After a contact with STT and their answer that they don't produce the 617 kit anymore, and then comparing some of the substantial differences that MB introduced in the 617a (mainly the combustion prechambers) and since my main reason to drive an old G is reliablity, I dropped the idea.
The engine swap for a 617a looked promising, but I was discouraged by the substantial legal paperwork that this involves with the car registration bureau in my country.
Finally I adopted the NA alternative as thoroughly described by amzimmy and must report that even when I did not do all the work he did, the results were just fantastic.
For those who might be interested, here is what I did:
Since I am lucky enough to have an engine with only 100.000 miles on it, I discarded all what involved replacements of pistons or other inner parts of the engine.
First thing I did was to have a new exhaust manifold built by the best specialist in town. Since my G is a LHD one, I had room enough to build a perfect 5 to 1 manifold of absolutely equal lengh tubes instead of the 3 to 1 / 2 to 1 / to 1 layout he had to adopt due to interference with his steering column.
The rest of the exhaust pipe was built following his design.
The cylinder head was not ported, just much care was taken to fit manifold and gaskets perfectly.
Just with this, a noticeable difference was evident.
Then it was time to go to a good injection pump specialist. The instruction was "just pump as much fuel into the engine as it is able to burn, I will be responsible if it breaks".
The outcome was awsome. I did not dynotest my engine, but I think I can well describe the difference this way:
Formerly, cruising on the highway at about 3700 rpm, you could push the pedal to the bottom (to pass a truck) and nothing much happened. You very slowly climbed to 4100/4200 and, if lucky, to 4300 rpm. Now, you reach 4300 in a wink and, if not careful go past the red line.
In order to play it safe, I had the radiator rebuilt with a 4 line of tubes panel and replaced the original air conditioner one with a more modern design that permits better airflow.
A EGT instrument has already been ordered from Summit Racing in the US and is ready to be connected so as to keep an eye on this important element.
I still feel that a 617a (or other turbo engine) swap, may still have some performance advantage at high altitudes, but I also did not feel completely comfortable with the idea of having a 300GD body and frame with an engine that never belonged to it.
In a couple weeks I will join a group of other G owners (we are just a handful here) in a hill climbing trail and be able to compare performances.
Thank you again to all those who shared their experiences with me and specially to amzimmy for coming up with a great idea. |
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amzimmy
Elite Veteran
Date registered: Apr 2006
Location: South Africa/Italy
Vehicle(s): GD300 1981, Alfa GT 3,2 V6, Alfa Brera Q4 3,2 V6.
Posts: 850
| RE: POWER INCREASE FOR 617 ENGINE
I am glad that I could be of help. Wish you many happy G-hours and happy trails.
Enjoy! amzimmy  |
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: POWER INCREASE FOR 617 ENGINE
Very nice! Please absolutely do report on your EGTs. I don't seem to be able to find much specific info on what Benz's are running in that regard. I had unwanted results when I fueled hard enough to push temps into the 1500 range consistently on long grades. Now I keep it down to 1200-1300 max (900 level highway cruising) and have no problems. The trouble I had was an unidendified knocking from the engine under certain conditions. Never did absolutely define it's origin, but have not had a trace of it since dialing the pump back a touch and using the right foot to modulate exhaust temps. All the best and looking forward to hearing of your EGTs. Thanks for the post! -Dave G. |
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petermerle
Expert
Date registered: Apr 2006
Location: Cape Town ( deep south )
Vehicle(s): W460 *1, W123 *2, W124
Posts: 1315
| Re: POWER INCREASE FOR 617 ENGINE
Where is the best place to fit the EGT on the 617?
Peter |
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emlmcb
Veteran
Date registered: Dec 2006
Location: Buenos Aires, Argentina
Vehicle(s): 1986 LWB 300GD / 1998 E320 / 1996 LWB G300TD
Posts: 119
| RE: POWER INCREASE FOR 617 ENGINE
Auch. you realy push it hard!.
As a private pilot I was always taught not no go past 1100 degrees on EGT in any piston engine and I intended to teach my right foot to stay below that.
Now that you tell me that you had consistently run with 1300 degrees I will have to do some research. maybe a water cooled diesel can stand more exhaust temperature that an air cooled gas engine in a plane.
By the way, where did you place your temperature sensor. As far as I have always seen them, they are some 1,5 to 2 inches from the head exhaust port. |
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: POWER INCREASE FOR 617 ENGINE
My sensor is in the exhaust manifold between the runners for cylinders 3 and 4, just ahead of the opening to the turbo. There's no free lunch with the diesel. To get performance you have to burn fuel, when you burn fuel you get heat. That's why I'll be really interested to see what you have for EGTs when you told the mechanic to give it all the fuel he can. I also want to try bypassing the silencer and see if my temps go down, or at least rise more slowly. I have the 2.25" exhaust from the 280 in there still and although the silencer is made to handle flow from a 2.8 liter petrol motor to 6500 RPM, it may still be too restrictive to let the 3 liter turbo run free to 4k. Always another project..... :^) -Dave G. |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: POWER INCREASE FOR 617 ENGINE
Dave, I think you can run without much of a muffler with a turbo because the turbo itself muffles a lot of the exhaust noise. Go bigger and it might be a little bit throaty but not obnoxious. I know of someone who removed all of the mufflers on an early Dodge Cummins turbo D and it isn't that bad. I was amazed. Tremendous improvement in power and torque he tells me. Trying the bypass will tell you a lot.
Stock exhaust is right at 2.5" in the TD turbo D. I think there is more to gain by going bigger than that. I'm thinking 2.75 or 3" might be right with a matching oversize silencer. I'm thinking there is no point in going with Stainless Steel behind the diesels. The exhaust on our TD is still very healthy at 370,000. Diesels do not rot exhaust components like the petrol drinkers.
-Dai |
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VonEpp
W124 Host
Date registered: Sep 2006
Location: Australia
Vehicle(s): w114, w124 & w460
Posts: 357
| Re: POWER INCREASE FOR 617 ENGINE
I've always found stainless steel exhausts better behind a turbo (titanium is better) due to heat conducting properties - as opposed to ferric steel. |
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Tjærand
Extreme Veteran
Date registered: Oct 2006
Location: Nøtterøy, Norway
Vehicle(s): 1996 G320
Posts: 403
| RE: POWER INCREASE FOR 617 ENGINE
I have 3" pipes all the way and no muffler. The turbo kills all engine noise allthough it is indeed throatish (I like it, some will say it sounds too agressive). As a bonus you get a very pronounced turbo wailing. Good for impressing the local japanese car racers. You might not want stainless steel in the pipes as they resonate a LOT. Tried stainless on a old S-class and it sounded very shrill and had very weird "singing" overtones.
When I removed the muffler I noticed a slightly better torque and gas response allthough it might have been the cooler sound from the pipes that made it feel faster ;-) |
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emlmcb
Veteran
Date registered: Dec 2006
Location: Buenos Aires, Argentina
Vehicle(s): 1986 LWB 300GD / 1998 E320 / 1996 LWB G300TD
Posts: 119
| RE: POWER INCREASE FOR 617 ENGINE
I PERSONALLY WENT WITH A MIXED DESIGN. MANIFOLD IS STAINLESS WHILE THE REST IS ALUMINIZED STEEL. THE MUFFLER IS JUST BSRELY ENOUGH NOT TO GET IN TROUBLE WITH POILICE WHILE DRIVING IN THE CITY.
SINCE MY LAST ENTRY, I DID SOME RESEARCH AND LOOKS LIKE UP TO 1300 DEGREES (F) IS A SAFE TEMPERATURE FOR A DIESEL MEASURED AT THE EXHAUST PORTS. IF MEASURED AFTER THE TURBO (IF ANY) IT SHOULD DROP BY 200/25 DEGREES. OVER 1400 YOU ARE RISKING YOUR ENGINE'S INTEGRITY. |
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Bier
Regular
Date registered: Apr 2006
Location: Pretoria, South Africa
Vehicle(s): 1999 290GDT W461
Posts: 86
| RE: POWER INCREASE FOR 617 ENGINE
My EGT gauge was installed by a local diesel specialist workshop, according to them a diesel should NEVER run above 720 deg. C (1328 deg. F). My EGT gauge also triggers an alarm should the temp rise above 720 deg.C, when I cruise at 120 km/h (75 mph), my EGT reading is usually around 400 deg. C (752 deg.F).
This is for the OM602 (290 GDT) motor. They usually apply the same rules to other turbo charged diesel motors (Toyota and Isuzu), thus I figure it should also be valid for the OM617A motor.
Attachments
----------------
 EGT_FAQ.pdf (205KB - 27 downloads)
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| Re: POWER INCREASE FOR 617 ENGINE
dai - 3/27/2007 10:37 PM ...Stock exhaust is right at 2.5" in the TD turbo D. ... Hmmm. Interesting. I got the downpipe behind the turbo from the car my motor was in and it was right at 2.25 ID. Maybe they made them bigger in later cars. My motor was from a '79. I'm going to try the muffler bypass, but my exhaust system is in perfect shape so I can't see replacing it. Might try something bigger if it ever needs replacing, but as straight as the G exhaust is, I just can't see the potential for a lot of gain unless one was working the upstream side too, a-la higher boost pressures or something. I think I'd spend my money on an intercooler before bigger exhaust than I have now. I need to get a good working tach in there before I can do any comparison tests though. One of these days.... Right now the project on the table is the transmission. I got that manual from Barry and was glad to see that the 4/5 gear sets can indeed be interchanged between the boxes. R-3 all run on a one-piece countershaft, so they can't be swapped independently, but the input shaft, constant gear, 4th gear, and synchro can be moved to put the OD in the granny low box. So now the question I need to decide on is what do I want, gear wise. It would be nice to have the OD, but I'm not sure it's worth the big 3-4 jump it'll entail. The close ratios from 3-5 in the granny low box are wending their way into my heart. I should probably try the granny box as-is and run it on a long trip (hoping to get to Nor Cal end of April) before I start to Frankenstein anything.... -Dave G. |
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amzimmy
Elite Veteran
Date registered: Apr 2006
Location: South Africa/Italy
Vehicle(s): GD300 1981, Alfa GT 3,2 V6, Alfa Brera Q4 3,2 V6.
Posts: 850
| RE: POWER INCREASE FOR 617 ENGINE
Bier - 3/27/2007 3:48 PM
My EGT gauge was installed by a local diesel specialist workshop, according to them a diesel should NEVER run above 720 deg. C (1328 deg. F). My EGT gauge also triggers an alarm should the temp rise above 720 deg.C, when I cruise at 120 km/h (75 mph), my EGT reading is usually around 400 deg. C (752 deg.F).
This is for the OM602 (290 GDT) motor. They usually apply the same rules to other turbo charged diesel motors (Toyota and Isuzu), thus I figure it should also be valid for the OM617A motor.
Bier where did you get the EGT and fitted? send me an email with some picks maybe, or PM. Thanks
amzimmy |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: POWER INCREASE FOR 617 ENGINE
Dave, I'll bet the bypass will buy you a lot of airflow.
I would give up a smooth 3-4 jump for the overdrive any day. I have the OD and it makes the truck spin at 3000 at 65. You would have the ideal setup. A super low and an OD. The motor has the torque to handle a wide 3-4 jump. My $.02.
Amzimmy, I might be able to help you on the pyrometer if your local buddy can't. The local turbo guy I know has one he says is very good.
Cheers friends,
-Dai |
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amzimmy
Elite Veteran
Date registered: Apr 2006
Location: South Africa/Italy
Vehicle(s): GD300 1981, Alfa GT 3,2 V6, Alfa Brera Q4 3,2 V6.
Posts: 850
| Re: POWER INCREASE FOR 617 ENGINE
dai - 3/27/2007 11:51 PM
Dave, I'll bet the bypass will buy you a lot of airflow.
I would give up a smooth 3-4 jump for the overdrive any day. I have the OD and it makes the truck spin at 3000 at 65. You would have the ideal setup. A super low and an OD. The motor has the torque to handle a wide 3-4 jump. My $.02.
Amzimmy, I might be able to help you on the pyrometer if your local buddy can't. The local turbo guy I know has one he says is very good.
Cheers friends,
-Dai
Dai thanks for the offer, I'll definitively will let you know. I have a ......maybe stupid...... question: What are you and Dave talking about "I would give up a smooth 3-4 jump for the overdrive any day" "The motor has the torque to handle a wide 3-4 jump"? I may be a bit "blond" (no offense meant) but I can't make sense on this one.
amzimmy |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: POWER INCREASE FOR 617 ENGINE
He is talking about swapping out gears between boxes to get the gear ratios he wants. Some of the boxes have very low gears and close ratios between each jump. 1-2, 2-3, 3-4, 4-5. My limited understanding of the iron casing transmissions is that you can get super low first with a 1-1 ration in 5th. There is also an Overdrive box that gets you a taller fifth but you then don't as low a first. Sounds like what Dave discovered is that to have the low and the overdrive the compromise would be a larger step between the third gear shift and fourth.
Having driven for a lot of miles with the overdrive five speed I wouldn't give up the OD for a lower gear. It just makes driving around here at these speeds pleasant and easy on the motor.
Am I reading this correctly, Dave?
-Dai |
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Iver460
Veteran
Date registered: Apr 2006
Location: Norway
Vehicle(s): '82 300 GD STT Cab (two other Gs in family)
Posts: 291
| Re: POWER INCREASE FOR 617 ENGINE
I was bidding on german Ebay for a 711.117, the iron cast 5-speed with overdrive, but lost it.
In my eyes it's the perfect manual box for a G. It's 4,695:1 in first and 0,806:1 in 5th. On my first offroad event with the Getrag I found myself using the clutch much more than with my old 4-speed, 3,822:1 in first is a bit too high. On the other hand, much easier to drive on the road, so I guess there's a question of wich direction in which you'll point your G. |
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amzimmy
Elite Veteran
Date registered: Apr 2006
Location: South Africa/Italy
Vehicle(s): GD300 1981, Alfa GT 3,2 V6, Alfa Brera Q4 3,2 V6.
Posts: 850
| Re: POWER INCREASE FOR 617 ENGINE
dai - 3/28/2007 3:14 PM
He is talking about swapping out gears between boxes to get the gear ratios he wants. Some of the boxes have very low gears and close ratios between each jump. 1-2, 2-3, 3-4, 4-5. My limited understanding of the iron casing transmissions is that you can get super low first with a 1-1 ration in 5th. There is also an Overdrive box that gets you a taller fifth but you then don't as low a first. Sounds like what Dave discovered is that to have the low and the overdrive the compromise would be a larger step between the third gear shift and fourth.
Having driven for a lot of miles with the overdrive five speed I wouldn't give up the OD for a lower gear. It just makes driving around here at these speeds pleasant and easy on the motor.
Am I reading this correctly, Dave?
-Dai
Then basically you are talking about the 711.117 gearbox, the one I have in my G with the "Granny" gear as 1 then 2-3-4-5 (end drive 1:1). Is there a way to fit an OD additional to this GB? Or am I interpreting this wrongly?
amzimmy |
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| Re: POWER INCREASE FOR 617 ENGINE
AMZ, I have the transmission you have in your truck sitting on my garage floor right now. Right next to it is another one that's identical in every way except for the gear ratios that are in it. If you look at Harald's site on "G transmissions" I'm talking about the G-1/18-5/#.## series of 5-speed transmissions. http://4x4abc.com/G-Class/transmissions/getriebe.html What I'm thinking of doing is changing some parts between the two boxes to take the 4th and 5th gears from the overdrive box and move them into the "granny low" box. This means that instead of the 3-4 change being from 1.743 to 1.278 (a 27% drop in revs) , I'd be jumping from 1.743 to 1.000, a 40% drop in revs. This is what I'm a little worried about. The fact that if I'm turning 3500 rpm when I make the gear change, I'm dropping to 2000 rpm on the gear change alone, not counting the road speed loss (typically another 10% for an ultimate rpm after change of 1750) associated with the time required to make the change. I know you're confident in the motor's torque band, Dai, but the above still seems dicey to me. I'd be literally FORCED to wring the motor out over 3500 for EVERY 3-4 change. The other thing that's in my mind is to maybe just use the OD trans and see if I get myself into situations that NEED the lower gears before I launch into the Franken-Trans project. I know that I can use the OD on a daily basis, where the need for lower gears might be a couple-times-a-year thing. I think if I have to make a choice between the boxes as they sit, prudence demands the OD box, as cool as a 60-1 crawl ratio would be. And yes, I could get OD from bigger tires, but bigger tires bring other complications I won't go into as I've already diverted this thread way too far off course. -Dave G. My appologies for the thread hijack. :^(
Edited by hipine 3/29/2007 12:05 PM
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amzimmy
Elite Veteran
Date registered: Apr 2006
Location: South Africa/Italy
Vehicle(s): GD300 1981, Alfa GT 3,2 V6, Alfa Brera Q4 3,2 V6.
Posts: 850
| Re: POWER INCREASE FOR 617 ENGINE
Thanks Dave and Dai, now it makes sense to me. I thought that I could have the solution both way having the 711.116 (correction) GB with the "granny" and an additional OD gear 0,806 for the problem that I have since the engine has still a lot of power at 4000 rpm at 125 km/hr and could do with that additional gear!
Eduardo, you will find that due to the increased power-band from 2500-3500 rpm, there is a possbility to have your final gear at the 0,806 ratio instead of the 4th on 1.
Dave I really don't think that you have hi-jacked the thread, the issue of the GB is hand in hand with the increased power of the engine.
Thanks again,
amzimmy |
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