Hello guys!

I just got a 617 Turbo engine that was in a totalled car. I'm planning to replace it for my 617 NA which moves my '82 300D.

I already got the parts to overhaul the turbo engine, so I will get all the power it can pump.

I wanted to ask you what do you think about setting up a water-to-air intercooler with my fresh engine so I can raise the boost up to 15 psi? I know the engine is limit protected to 16 psi due to high EGT's caused by overboost. How much power do you think I'll be getting from the engine? I know the 617 turbo federal gives somewhere around 125 HP. I would like to go somewhere around 175 HP with this set up. What do you think?

I think you'll get about 140 hp if you do a perfect job in setting the intercooler up to match the engine and all the plumbing is of sufficient size.

This will reduce the 0-60 times down into the 11.5 second range or so.

You'll need to modify the IP to provide additional fuel to get to that time........a long and arduous task without a proper flow bench.

Think it's worth it to you?

Thanks for the reply Brian. Only 140 HP? What would I have to do to more power?

I want to increase the power of the engine but without damaging/modyfing any internal components. I know the turbo can put lots of pressure in the intake manifold, so I thought of the intercooler to keep EGT below 1200 ºF and since the IP is limited to 16 PSI I thought 15 PSI would be a nice number considering usually the 617 runs with a boost of 8-10 PSI.

Please give me some further details. I don't want to mess up fresh engine.

Thanks!!!

You're not going to get more than 140 hp from a 617 unless you ask for that power for very short periods........maybe 10 seconds.........and then back off before you melt a piston.

The intercooler is helpful but it's not magical.

The factory gets about 30hp by adding an intercooler and a turbocharger to a
n/a OM606 engine..........it produces 175 hp with a four valve head.

Do you really think you can do the same thing with an OM617.........five cylinder engine..........two valve head......... and no crossflow?

What do you need to do for more power?

Well, I recently drove an SLK, V8 with the Renntech package, it had 495 hp and would go to 120 mph faster than my SD can get to 50. Would that be enough power for you?

Don't forget the stock turbocharger is too small for 15psi too. It's only ramming in more hot air, which you don't want.

The stock 617 IP is good to about 185-200hp... 17-18psi is realistic WITH a proper turbo being I/C.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Since when?

Know of anybody who ever got there?

FI on here has told me that's about its limit.



Nope, no clue of anyone to that point. The stock turbo is a big limit, even at 13psi the air is so hot as the turbo is too small.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

How does the size of the turbo affect the air temperature?

Efficiency. Turbo basically superheats the air as it is mismatched.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Well, Lance is currently at 100 rwhp. When he gets to 185 hp, please let me know.

Well I mean 180-200 crank. that's about 140rwhp or so factoring a 25% loss.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Small turbo spools up quickly to get you going but very inefficient at high compressor rpms. Kinda like blowing very hard through a small pipe.

Big turbo is more relaxed at higher cfms but it takes longer to get there. Lots-o-lag.

Sixto
... stay tuned

If you compress a given amount of air to a given pressure the temperature will increase approximately the same amount regardless of the size or type turbo that you use. The process is approximately adiabatic (no heat transfer during the compression), and is independent of the equipment used.

If that were true in practical applications then there would be a single turbo design in use from leaf blowers to aircraft carriers. In reality the same Subaru and Evolution long blocks have a number of turbo options for different applications. I don't understand the thermodynamics behind it but I assume the engineers that design these engines do.

Sixto
... stay tuned

I was actually answering Hit Man X ("Efficiency. Turbo basically superheats the air as it is mismatched."). The point was that the air is heated the same amount (at the same boost) regardless of the specific turbo design.

I agree that the turbo size/design needs to be matched to the engine for various other reasons, including response time.