early tubular exhaust vs. cast iron manifolds

[creempuf]

I'm considering using the early 230sl tubular exhaust manifolds as opposed to the typical cast iron manifolds used during most of the 113's production for my 71 280sl. I like the high performance look of the early pipes as opposed to the mundane cast clumps. Are there in fact any actual performance differences?  do they flow better? are they louder? from a cost point of view, I can see why Mercedes switched to the cast iron manifolds as the tubular ones are much more complex requiring laborious bending, cutting, fitting, and welding of the various tubes

[DaveB]

I've never seen any specs but there'd have to be a slight performance boost. That looks like a good set you have there so why not. As you probably know, you'll also need a different, shorter, set of front pipes to join these headers to the front muffler. The pipes are still available from MB.

[al_lieffring]

What I noticed about my 230 with the tube headers was the sound (tone) above 3500 rpm. I think the performance difference between the 2 cars had more to do with the axle ratios the they had. 3.75 v 4.09

[RickM]

Are there in fact any actual performance differences?  do they flow better?

Are they a direct fit?

FWIW, unless someone has flowed these on a bench and dynoed side-by-side it's impossible to answer these questions accurately.

Tube headers do not automatically equate to increased performance. For one these are not equal length.

I do agree that they do look nice.

[creempuf]

I have test fitted the headers to the 280 head so I don't see any issues there. I just dropped them off for sand blasting and then they will be ceramic coated inside and out.
I am considering making a custom exhaust, similar to that of a 300sl. More specifically the 300sl roadster as the headers meet at whats known as the collector, then from there it is a single large diameter tube, about 2.50inch diameter, going to only a muffler and no resonator. the stock 280 twin  pipes seem tiny and very restrictive. Any opinions or suggestions out there?

[Benz Dr.]

I have the early system on my car and it's a very strong engine. The 230SL has more power per litre than the 250  or 280SL. I always wondered why and I'm sure the tuned pipes make a difference. I'm using 10 litres per 100 KM ( WITH A 5 SPEED TRANS ) so I think the free flowing exhaust helps there also.

I'm not sure you can equate equal lenth pipes that are used on V 8 engines to this aplication. This is a straight six and the exhaust pulses would be different. The way the pipes are made they have a natural scavenging effect when the engine is running at speed. I'm sure they work better.
Twin pipes in this case will flow more than one single pipe. You only have so much room under the car to fit everything which is already very tight. A larger single pipe probably wouldn't flow as much and would likely give you problems with clearance. If you could omit the resonator it would give you more clearance.

It's not just the pipes that you need. There's a small bracket on the sie of the block that holds the throttle linkage. You have to put that on the engine and change the lenght of the rod that comes from the fire wall. This is all needed to clear the manifolds with throttle linkage that is a fairly tight fit.

The heat shield is also different. I don't think that part is available any more. Maybe someone knows but I asked for one a while back and was told NLA.

[66andBlue]

..  The heat shield is also different. I don't think that part is available any more. Maybe someone knows but I asked for one a while back and was told NLA.

Dan,
I am not sure which heat shield you have in mind but all three - the one between the manifolds #20 (0001410821) and the other two #31 and # 32  between the pipes and the chassis (1134900030 and 113492 0330) are available from SLS.  #31 was NLA and it could be that SLS now sells a repro part.

[RickM]

I'm not sure you can equate equal lenth pipes that are used on V 8 engines to this aplication. This is a straight six and the exhaust pulses would be different. The way the pipes are made they have a natural scavenging effect when the engine is running at speed. I'm sure they work better.

I'm not looking to start a pissing match (really) but I feel that performance claims should be backed by irrefutable data.........

FWIU the "efficiency" and pulse synchronization associated with equal length headers does not apply to V8s exclusively. It's applicable to most normally aspirated engines.  If you look at Porsche 911s the factory went with equal length headers on their flat 6 engine from the beginning. Straight six? Look at modern performance oriented BMWs. Some may use a crossover pipe for equalization and others may not....seems to be a bit of controversy regarding effectiveness.

As you know many factors go into tuning the headers and exhaust.....The ID/shape/finish of exhaust ports, header ID/config and exhaust pipes need to be designed to work in unison in order to deliver the desired result. Any one point can become a bottleneck and counteract anything up or down stream....from the intake to fuel delivery. 

Unless you compare side-to-side on a dyno these performance gains are guesses.

[Benz Dr.]

Rick.
. Real high performance engines tend to have equal lenght headers so it makes sense. I think that the early headers do give more performance but there are so many other things to consider it might be very hard to get two cars that are completely similar in all ways save the exhaust to make a fair comparison.
So it's probably moot at best.

[RickM]

Rick.
. Real high performance engines tend to have equal lenght headers so it makes sense. I think that the early headers do give more performance but there are so many other things to consider it might be very hard to get two cars that are completely similar in all ways save the exhaust to make a fair comparison.
So it's probably moot at best.

Agreed!

[RickM]

I have test fitted the headers to the 280 head so I don't see any issues there. I just dropped them off for sand blasting and then they will be ceramic coated inside and out.
I am considering making a custom exhaust, similar to that of a 300sl. More specifically the 300sl roadster as the headers meet at whats known as the collector, then from there it is a single large diameter tube, about 2.50inch diameter, going to only a muffler and no resonator. the stock 280 twin  pipes seem tiny and very restrictive. Any opinions or suggestions out there?

Do you know the type of ceramic coating? A highly regarded product/system is Jet Hot. http://www.jet-hot.com/techcharts.html

[Benz Dr.]

I have a guy that does all my manifolds. Not sure what he uses but it's good. Part has to be bare clean metal and then the stuff is sprayed on - any colour you want. It's baked on in a big oven for a while and it won't come off.

It really works wonders on 190SL engines where the headers are right under the carbs. They will hot soak and boil out the gas making them hard to start when hot. This just about cured that problem. It's actually just as good as heat tape.

[menesesjesse]

I have the header system on my 230sl.  I just would like to point out linkage issues may arise.  I believe but am not sure that the linkages that are used are different.  I know the Auto vs Man lengths are different because I saw the differences when I bought a spare motor with cast manifolds.  Just an observation but I think there is a difference.  Maybe someone can confirm this.
Jesse

[mkbull]

Recently gone through the same set of considerations. I have both sets of headers available to me but considering performance and linkage issues eventually decided to stick with the later 280 cast headers.
I can confirm for sure that the linkage is effected if you choose to use the 230 headers, as is the heat shield. These are different to accommodate the slightly different route that the uplink rod has to take through the manifold. The swivel linkage that bolts to the engine is also different the 230 version is mounted slightly further back than the 280.
In the end after discussions and research I have opted for a custom stainless 2 into 1 into 2 system. Big bore 2 as soon as you can this theory is adopted by many other engines including formula one cars ie. collect the exhaust gases about as soon as you can as smoothly as you can.
Harley systems claim a significant boost in power when this is adopted over the stock two pipe system, there is also a corvette 2 into 1 system that claims to offer a 29hp boost!
Mark