Time For Performance Advise
 

Folks -
I've had a long running thread on "Diesel Discussion" on my build, an '85 OM617 in an S-10 pickup with an '83 240D 4 speed manual (aluminum case Getrag) behind it. The truck is ONLY used as a race truck, doing Land Speed Racing at the ECTA Ohio Mile in Wilmington OH (confusing as I live in Wilmington, NC). Anyhow, I have the truck up and running and have made a few passes with a best speed of 101.1918 - a track record (but I'm the only one to ever have run the class).

Just to introduce myself. I'm retired and have done MUCH Diesel dyno work in my work life along with some engine building though all of it was putting the engine back to stock then doing specific mods aimed at emissions reduction. So Diesel engine work is "old hat" but performance work on an OM617 is new.

The engine is fairly stock with new mains and rear seal. I have a set of Greazzer's "315" Monarch nozzles and a T03 compressor with trimmed wheels done by Tim's Turbos - Tim has experience with Diesels in LSR. I'm currently fitting a water-to-air intercooler which will run ice water.

Now it's time to get serious about the engine. I'm a bit low on cash as my build money has gone into getting Mutt (the truck's name) running so I'll have to recover a bit before I can do anything TOO expensive. I will have a Dieselmeken pump and other goodies eventually but in the meantime I'd like to get out of the engine whatever I can without driving over the crankshaft.

Please post your suggestions. Pretty sure I'll want to advance the IP timing a few degrees and maybe the cam timing as well. Any advice on this is more than welcome. Also any other tips that don't require a ton of money.

It's my habit to build the basic engine/chassis and then work the assembly up in power and performance. Clearly this build is no different!

Thanks

Dan

Hi Dan,

As you know, more fuel, more air, less parasitic drag of all types, which includes less weight since that is the greatest parasitic drag out there.

From my personal experience, I've noticed the greatest "gains" by the following to my clunker:

1. Differential: Gearing to the 2:65LSD is major IMO;
2. Nozzles: Ran a set of R&D #242s and wowza ... a lot of fuel with a lot of gains;
3. Got rid of some pumps, e.g, PS, WP, et cet. Each adds a little to the puzzle. Admittedly, there is an exchange rate going electric or going without.
4. Narrower tires & lighter rims -- less drag overall. I got the 5.5 aluminum ones so not sure what youre truck will work with. Those rims made a very slight difference.

Not sure when the #242s will be prefected, but those are certainly winners in my book. Finding a manual steering box should be easy for your truck. EWP is pricey, around $400 plus the allied parts are still in the final R&D phase, but you can make do with what you got for the most part.

Hope the above helps.

Propane or methanol. Probably methanol as it can be done cheap.

The mods you do I reckon' will be regulated by your class at the track.

Diesels respond to the same mods as any engine, improve it's ability to process air and fuel and you'll get more power. Set your HP goal and build up to it. OM617 suffers from not being a cross flow head so anything you can do to improve flow in and out will help. You can port and polish both intake and exhaust because the diesel, being a dry intake doesn't depend on turbulence to maintain fuel atomization.

You already have plans for a Dieselmeken pump which will serve your fueling needs. I would not mess too much with "turning up" your stock pump too much because the more fuel injected, the more degrees of crank rotation and you end up with higher exhaust temps because you're still injecting much later than you should.

On the intake side, bigger turbo, intercooler. On the exhaust side, tubular manifold will help. Since you're doing LSR, you really don't need to worry about a quick spool up. A larger A/R fixed geometry turbo should work fine. If you want to keep the custom turbo you have now, post up a picture of the map and it will determine how much HP it will support.

Thanks guys!

I'll see if Tim had the map still (it's been a while since he built it and I didn't get a map when he sent the turbo back). His goal for the build was about 15 PSI and about twice the volume - a great concept from my experience. I can get around 20 PSI with the boost controller cranked up but I think the extra intake heat offset any boost gains, hence the intercooler (which I knew I'd need anyhow).

The EGT's are only 650ish at the end of the track so I have plenty of room to mess with timing and still be OK. I'm thinking maybe I'll nudge the timing up a tad at a time and see when it A) gets too hot or B) falls on it's face.

I've also just added an intake manifold temp readout (Auber to match my EGT) so I can see what the intercooler does for me. I may make a run with the intercooler pump off just to get a feel for the intake temps w/o the intercooler.

Lucas - No "extra" fuels are allowed in my class (must be commercial Diesel fuel or Event Diesel if offered - ECTA allows pump Diesel). The way the LSR rules are structured I can't add N2O, propane, or anything else without moving to "Unlimited Diesel" which has NO displacement limit - I'd be screwed. I REFUSE to cheat so I have to abandon that idea - oh, well.

Mark - when can I drag you up here with your trusty timing light system? We could plan a dyno day and make actual measurements of the results - like science or something!

I have no vacuum pump, power steering, power brakes, A/C, power door locks (or ANY door locks) or any of that other stuff. As far as weight - the truck is 3080 with me in it. You guys won't believe this but weight has virtually no effect on top speeds in LSR unless you're running a LOT more vehicle than I am and then it is a small effect.

I've been running a 28" rear tire with a 3:08 gear - the purpose of the tall tire is to lower the final drive ratio. I also have some 23" tires that I have yet to try so I have more things to mess with. The 28" tires are drag radials and are wider than I wanted but they were the only 15" tall tires I could find with a speed rating.

Again, thanks all for the input.

Dan

Hi Dan,
I've missed the Carolina GTG ... through my own negligence and not being able to keep track of events. I've been putting off a 2 level ACDF, but my time is coming. Which means a liquadation of my cherished MB stuff so that I can hire someone to finish my project ... however, I do need to come on up there and check it out !

The compressor map is pretty key to properly fueling your engine. If you can't get the turbo map, maybe Tim can provide the "trim" of the compressor wheel.

I have a spreadsheet that will calculate max HP for a given turbo and I can plug the numbers in and get some useful information.

Mark - The guest room is ready and waiting. Just give me enough notice so I can schedule with the dyno shop.

I'll drop a note to Tim and see what he has. THANKS for the offer of your nifty calculator!

EDIT: Note now sent.

Dan

I've had Emails back and forth with Tim and he's looking thru his old records. Off the top of his head he said he recalls a "X" trim but said "that must be a typo" - hence, he's looking. He's worried that I may be limited by the turbine (hot) side as the T03 should have enough for more HP than I'm making. He also supports the need for an intercooler.

Dan

Stuff I've tested that "felt" better:
Advanced timing (until it knocks, then retard a bit) ~28* if you drip time it.
Check the cam timing (measure valve lift, there's a procedure up top on this site)
Complete ALDA removal (you've already done this I think?)
Electric fan or no fan at all (noticeable difference)
"Ported" head-I haven't run it in a car though, so this one is TBD

I don't have numbers to back these up, just what people have said:
Bored out prechambers (can be done by hand if you're careful)
Tweaking inside the pump (PM user OM616)
Stretch the fuel return spring or replace it
Add a lift pump pre-injection pump to cut back on losses (smaller gain)
Trimmed delivery valves-this one can make your EGTs go really high as it makes your injection event longer

Did you smooth out your intake/exhaust at all?

Simpler - THANKS for the tips!

I don't find the cam timing thread you mentioned. A link, if you please.

ALDA is history.

I have an pair of electric fans on a dash switch so they only come on when I turn them on. I just flip the switch on the return road.

No head porting and the intake is basically stock except that the inlet is moved to the top of the manifold (see my build thread).

Not sure what to do with the lift pump. My total fuel line is about 18" long - the fuel cell is in the LF corner of the engine bay. I could fit another lift pump in there but the OEM one is not working very hard as it is.

Most of these are things to check off the list as I refine the set-up over time. At some point I want to build an engine from the pan up with everything optimized for power so some of your suggestions will probably get implemented in the "new" engine.

Dan

PeachPartsWiki: Do It Yourself Articles - Mercedes Vehicles

PeachPartsWiki: Measuring Timing Chain Stretch

I got a chance to do the "quick & dirty" chain stretch measurement and it seems to be spot on at 2 or 2.5* after. Either the chain was replaced at some point or there's an offset key in there - haven't checked that yet.

I have a 2* key and a 5* key. Should I retard this sucker a few degrees for performance improvement? Not hard to do as I'm looking at it.

I think I'll run out to PnP and grab an injector line to turn into a timing tool. How far is enough and how far is too much to advance the IP?

Thanks for all the help. Looks like I jumped the gun on ordering up the chain (unless there's already an offset key in there).

Dan

Doesn't hurt to have a spare chain, store it in a jar with oil.

When the engine knocks, you're too far advanced.

I tested propane on my 617.951.For a heavy SD it made my car take off like my 1999 s320.I used a propane torch with rubber hose run to the hole in air intake for blow by gases.I turned it on at full throttle.I have tank,and pressure guages,just need a hobbs switch.