weekend Wrenching - Page 62 - PeachParts Mercedes-Benz Forum

Mike D · #**916** 05-10-2011, 01:47 PM

Gael, if you decide to go with another Megasquirt and convert to electronic injectors let me know. I'm going to bite the bullet and order one of the special bits for the injector holes in the fuel rail blanks.

I need to make another set of fuel rails for a M117 and somebody else should get some use out of the bit when I am (temporarily) done with it.

GGR · #**917** 05-10-2011, 02:18 PM

Quote:

Originally Posted by alabbasi

Well then that settles it, you need to install the EFI

Hum.... OK: I first need to finish the Coupe properly and really see how it works, learn from it and then draw conclusions for the Pagoda project.

One lesson I already drew is that the five speed is not really needed. I have a 5 speed and a 3.27 rear end ratio on the Coupe, and though it works very well, the engine is so exploitable on a very wide torque and power band that it could do as well with four gears and a 2.82 rear end. The Pagoda is 200 kg lighter so it will take it even better.

GGR · #**918** 05-10-2011, 02:20 PM

Quote:

Originally Posted by Mike D

Gael, if you decide to go with another Megasquirt and convert to electronic injectors let me know. I'm going to bite the bullet and order one of the special bits for the injector holes in the fuel rail blanks.

I need to make another set of fuel rails for a M117 and somebody else should get some use out of the bit when I am (temporarily) done with it.

Mike,

I'm using D-jet fuel rails and injectors. They are a direct fit and there is no fabrication needed, and they look period correct

.

mercmad6.3 · #**919** 05-10-2011, 05:53 PM

Quote:

Originally Posted by GGR

Hum.... OK: I first need to finish the Coupe properly and really see how it works, learn from it and then draw conclusions for the Pagoda project.

One lesson I already drew is that the five speed is not really needed. I have a 5 speed and a 3.27 rear end ratio on the Coupe, and though it works very well, the engine is so exploitable on a very wide torque and power band that it could do as well with four gears and a 2.82 rear end. The Pagoda is 200 kg lighter so it will take it even better.

now you have learnt what mercedes knew 40 years ago with the W112 M189 and five speed. it's a waste of money LOL!.
I have a friend with a 350SL ,5 speed. it gets over 30 MPG on a trip and hes won a few reliability trials with it because of it's low fuel consumption. Most of the time it never sees top gear.
I think CIS is great,it's simple ,easy to diagnose and easy to maintain.
I've also seen a turbo volvo V6 producing 700HP at the rear wheels on a dyno which has CIS.
There is no restriction to how many horsepower you want to produce and just like the MFI,it uses a higher pressure to operate ,thus atomizing fuel better than EFI..
My 380's both do well over 25MPG average and I wouldn't expect better from a large car with a V8. The only real problem is that you cant tune Cis as precisely as a megasquirt (etc)
Dont forget the guy in OZ who spent 5 figures on converting his 6.9 to Motec injection last year. He ended up with 20 less horsepower .

alabbasi · #**920** 05-22-2011, 07:29 PM

Spent some of the weekend working on the 560SEC. The car was at one time converted to regular shocks so I put the SLS shocks back which came from another SEC parts car. I was missing some hardware so I went to junk yard and scored another set of SLS shocks (in case mine were no good) with all the hardware for about fifty bucks.

Took the car for a spin after I installed the shocks and it drove pretty well. One of the shocks appeared to be knocking so it may have been a smart move to get the spare set. Or they may have not yet pressurized with oil.

I seemed to have developed a miss. It's not at idle but instead, as you rev the car up. I suspect that it's a fuel pressure issue which could have been caused by it sitting for so long.

JiveTurkey · #**921** 05-22-2011, 08:01 PM

I feel so bad for you with that rusty 114 floor my friend. If I lived closer I'd help button it up with you. Lowes has long cold colled mild steel bars you can use for temp body braces for reasonable prices.

alabbasi · #**922** 05-22-2011, 08:57 PM

Thanks, I picked up some angle Iron so I should be set.I also have a very frustrating leak in the a/c system of my 560SEL. The car would hold pressure to 75psi on the high side. The rest gets leaked out. I replaced the condenser, low side hose and compressor.

I pulled a vac and it held, then I charged the system and used my sniffer to check for leaks. Nothing showed up at the condenser, lines or compressor, so I stuck it through the vents and up by the gas pedal where the expansion valve is supposed to be. Still no leak detected.

Any thoughts as to where this leak could be would be gratefully appreciated. It's going to get hot in Texas over the next couple of months.

JiveTurkey · #**923** 05-22-2011, 09:09 PM

I'm dealing with a similar issue on my 126. I'll charge the system and use dye to check for leaks and everything is kosher for anywhere from 500 to 3000 miles and then it loses its charge in a completely non-violent and undetectable fashion. I loathe working on AC systems because the fault is always some obscure part you've never seen fail before.

mercmad6.3 · #**924** 05-22-2011, 09:22 PM

Al, it might the lower ball on one of the shocks you have fitted .They are replaceable and I have new pair of lower joints here for them but hardly worth the hassle. it's often easier to replace the shock.

alabbasi · #**925** 05-22-2011, 09:34 PM

Thanks Ron

Not sure exactly what the lower ball is, but I have two spare shocks so I will check them out.

GGR · #**926** 05-23-2011, 08:22 AM

On my side I was able to put the transmission back together and back in the Coupe. I also sorted out some clutch problems I had (wrong release bearing) so now it all works well.

I also got the replacement wideband O2 sensor so I was able to work on the tuning. I'm using TunerStudio and I also got "VE analyze live" which tunes the car autmatically while driving. It's quite amazing. The car now works very well. I still need to sort out a miss I have when I open the throttle after over-run. The rest is now fine tuning.

On the chassis side I still need to replace the steering box as this one has quite some play. I also need to work on the rear axle to add a bit of camber.

I'm now reaching towards the end of this project, at least on the mechanical side, as I will need to have a new paint at some point. I'm very happy with the result. The car is very fast and tight, and remains very driveable in all kind of traffic situations. I was a bit afraid at lower rev because of the AMG camshafts but they're really fine. It's a good balance between performance, driveability and comfort. I hope I will have the occasion to compare it with a 6.3 on a track day, as this was my target in terms of performance. I think it will do better as the car is lighter and tighter. The engine pulls hard, but in a less brutal way than th 6.3. I think the 6.3 may have a slight advantage at lower revs, but mine may take the advantage at mid-range and definitely at higher rev. It really pulls hard until past 6000 rpm. I also hope I will be able to compare with an AMG 126 or 107 with manual trans. The AMG setup includes some head work that I didn't do, and a higher compression ratio than mine. But I believe the programmable fuel & spark may compensate ffor part of that. My car may be slightly lighter, but the AMG 126 and 107 manual trans had taller rear ends, like 3.46 instead o my 3.27. It may be an intersting comparison.

Lessons learned will be used on the Pagoda 5.0 manual trans project, but that will come later. I'm happy I already have all the essential bits for that one also now. My idea is to keep it a bit simpler and a bit less perormance oriented than the Coupe, more like perormance touring.

GGR · #**927** 05-27-2011, 07:38 AM

While driving at WOT my injectors are maxing out and finally I end up with fuel starvation. A bit like driving with a clogged fuel filter or running out of gas. So I hooked up a pressure gage in the fuel circuit and guess what, the pressure is dropping steadily with a loss of 30% at wot. That means the fuel pump is not delivering enough flow.

I calculated that at WOT the engine fuel demand shouldn't be far from the 2l/mn the pump is supposed to deliver. Add to that wear, circuit flow resistance etc. and the engine does not get the amount of gas it needs at WOT.

So, I'm going to fit a new fuel filter to make sure that is not the problem, and I'm going to fit a spare Djet pump I have in parallel to keep pressure as it is but increase flow. A bit like the set-up on the 560 that has two pumps in parallel.

I have two questions in case someone knows:

will the electric circuit of the one fuel pump be able to run a second one without burning or blowing the fuse?

What is the flow rate of the stock D-jet fuel filter? Will it act as a blockage?

Thanks!

Mike D · #**928** 05-27-2011, 08:14 AM

What are you using to control the fuel pump circuit? The stock MB relay or the Megasquirt? Stock would be no problem. You'd need to check the fuse rating on the MS if it is what you are using. I believe I am running a 5 amp fuse in my MS.

mercmad6.3 · #**929** 05-27-2011, 08:24 AM

Quote:

Originally Posted by GGR

While driving at WOT my injectors are maxing out and finally I end up with fuel starvation. A bit like driving with a clogged fuel filter or running out of gas. So I hooked up a pressure gage in the fuel circuit and guess what, the pressure is dropping steadily with a loss of 30% at wot. That means the fuel pump is not delivering enough flow.

I calculated that at WOT the engine fuel demand shouldn't be far from the 2l/mn the pump is supposed to deliver. Add to that wear, circuit flow resistance etc. and the engine does not get the amount of gas it needs at WOT.

So, I'm going to fit a new fuel filter to make sure that is not the problem, and I'm going to fit a spare Djet pump I have in parallel to keep pressure as it is but increase flow. A bit like the set-up on the 560 that has two pumps in parallel.

I have two questions in case someone knows:

will the electric circuit of the one fuel pump be able to run a second one without burning or blowing the fuse?

What is the flow rate of the stock D-jet fuel filter? Will it act as a blockage?

Thanks!

just use the twin pump setup from a 420 or 560 with the fuel filter etc as a pump pack . You only need the one power feed as both pumps aren't working too hard normally and that is how they are wired up on the W126.

GGR · #**930** 05-27-2011, 09:27 AM

I'm running the pump on the stock circuit, not the MS one.

I don't have a W126 pump pack at hand but I have a second D-jet pump, so it makes it easier. I addition, the D-jet pumps have a security to keep pressure at 3-4 kg which is good in case the pressure regulator fails. I'm using the D-jet circuit with rubber hoses on top of the injectors and other places and I wouldn't wnat to see too much pressure in that circuit.