Why Headers for 16V 928s?

[Fixer]

I was wondering what you all thought about headers for US 16V 928s.

If 16V Euro 928s have the same exhaust manifolds (log) and make 300/310 crank HP. why would headers be needed at all on US 16V 928s?

Seems like a lot of effort and $ when it is the intake which needs to breath better for more power. Looking into my manifolds i thought the shape looked pretty good.

If Euro 928s have different Logs then scratch everything above.

[Landseer]

The 16V cast iron is restrictive if not port/polished like your AFM was.
(see Porken threads on rennlist)

MSDS headers prevent access to the clutch.

Answer is 85/6 32V SS pipes on 16V.

I dumpstered existing installed MSDS for that on 84 Euro.

HP wasn't a factor in my case, replacing MSDS was the driver.

With 32V SS, I can easily mate to stock 928 cats. (with a little bit of pipe heat / bend)


In my case, Euro 16V engine, 32V SS headers, 32V cats. Flowmaster Y transition into 3 1/4 inch single. Spintech resonator; single 3 1/4 inch out.

Nasty sound. (OK, like a mustang)

PCA guys got a kick out of it on the autocross course last Sat (at Tire Rack HQ).

[Fixer]

I cleaned them (my headers) up pretty well today- filed and honed, but my US 83s power deficit is due to valve size and intake manifold size. I think opening up this motor more (less back pressure) may make it run worse. Just a hunch.

16V Euro 928 made 310 with these manifolds, why bother spending money there? was my question/point.

I wanted to bring this up because of the thread on the Chinese MSDS 32V Headers and thought it was worth revisiting.

So if the cast iron 16V headers are the same on both the Euro and US cars, it seems putting headers on a US 16V 928 w/o intake enhancements is a waste of $$ and knuckles then. With MSDS 10hp for $1200 seems silly.

I have been looking for the'85-'85 headers for a while no luck. Will Continue.


Thanks Chris, your a wealth of information.

[Landseer]

In Euro trim there were no cats or air pumps those years.


Opening exhaust up seems to be the general consensus for some hp gains, amongst both the Euro and USA 16V guys that went before us. Some left more plausible data-based rationalizations than others. There are 12 years of posts on rennlist to dredge through from which to base assumptions.

I spent $185 on a pair of 85/6 pipes and mated it with a free 32V cat.
Perfect. A stainless steel system, emission compliant in most states that matter to me.


If I wanted performance, I'd concentrate on the electronic ignition system. That's where some gains seem to be.

Or forced induction, where the gains are truly meaningful.

Headers that aren't scavenging seem like a waste of money, especially if they block maintenance access and spew heat on the wrong parts such as motor mounts.

[Xlot]

Originally Posted by The Fixer

my US 83s power deficit is due to valve size and intake manifold size.

Its mostly due to the cams. Euro S cams are a lot better (S2 cams even better still).

IIRC, even the '78/79 K-jet 4.5 has better cams than the L-jet models.

[XLR8928]

For my own project, I'm running a set of euro cams, with the MSDS headers. I was thinking that the cast iron manifolds might really wake up if they were extrude honed. Just a thought...-K

[MPDano]

Originally Posted by Xlot

Its mostly due to the cams. Euro S cams are a lot better (S2 cams even better still).

IIRC, even the '78/79 K-jet 4.5 has better cams than the L-jet models.

I actually do feel like this is true as I can feel the difference, just sucks they put that slow 3 speed Auto in them.

My CIS throttle response seems to respond better than my S as well.

[Danglerb]

14 million magazine articles and ads are why headers get sold, that and Dynojet hp testing.

Stock US 16v makes about 185 rwhp, Euro S with no cats about 250 rwhp. I plan to put US 85/86 manifolds with some version of Jethot in and out on my US 83, but I would like to have full length tuned headers and exhaust on the Euro S where I figure as much as 40 hp might be possible plus a nice torque bump.

Headers if the tube diameter does match up can kill the low end for little gains on the top end.

[Fixer]

Originally Posted by Xlot

Its mostly due to the cams. Euro S cams are a lot better (S2 cams even better still).

IIRC, even the '78/79 K-jet 4.5 has better cams than the L-jet models.

That's good to know because it is relatively easy to swap cams.

S2 would be 85-86, so those cams and the SS exhaust manifolds. I think i found a donor motor, waiting to hear back. Very hard to find Euro stuff cheap.

Where is that motor serial number chart by year and Euro/US that keeps popping up, can't find it. Been searching.

Need to confirm what i am looking for.

[stepson]

Fixer,
That chart is located at 928 SPECIALISTS ONLINE STORE - 30,000+ 928 Parts - 928 SUPERCHARGER KITS!. On the left side, tips/links, then tech/specs, click on engine types

[Danglerb]

Buying Euro stuff requires checking all the numbers to be safe, way too many times heads and/or cams get swapped for US to save money, or not knowing any better.

Euro stuff can be pricey, it can also be pretty cheap, but no getting around its still about the best bang/buck.

[Fixer]

Thanks Stepson and Danglerb, I can pick up a M28/42 ('87-89 S4 Auto) 5.0L longblock with exhaust manifolds.

Condition unknown but motor is free. Much of the intake parts are missing, has O.E. SS headers but they would bolt up to my '83.

This is a 316 HP motor, if i can get it for a few hundred is it worth having to rebuild and transplant into another OB in you opinion. I have never rebuilt a 928 motor, what challenges do the piston bores present if they are bad? The aluminum liner-less technology is much different than American iron.

[Danglerb]

87 SS headers are 3 bolt, don't fit on early cars.

What you might get with that block is an education, but not likely a working motor for a early car. The core rotating assembly is usually fine, even rings and bearings might be OK, its the top end that gets pricey to fix, unless its a thrust bearing fail motor then its scrap metal.

[Fixer]

Thanks D, no info or history of this 316HP mystery motor.
pretty far drive for scrap metal. was hoping for '86 MY for headers.
they are open to any offers.
Porsche Motor

[Danglerb]

Usually make offer on a Porsche bit isn't free. Looks like its from an engine fire, but can't really tell from the picts, S4 block with good heads I'm thinking is worth more like $500 min as long as its not a thrust bearing fail motor.

I don't see that motor assuming all that is hidden is fine going back into a car for less than a couple grand, double that to go in another model.

[stepson]

I was gonna put a 32 valve engine in my first '84 when I started reanimating it. When I figured out that I was gonna have to rewire it for the computers that the 32 valve was gonna need coupled with the cost of refurbishing the upper end of the 32 valve engine before it went into the car.......well, I decided that 16 valve 310 hp motor looked darn good to me.

[Fixer]

Originally Posted by stepson

I was gonna put a 32 valve engine in my first '84 when I started reanimating it. When I figured out that I was gonna have to rewire it for the computers that the 32 valve was gonna need coupled with the cost of refurbishing the upper end of the 32 valve engine before it went into the car.......well, I decided that 16 valve 310 hp motor looked darn good to me.

310HP sounds darn good to me also!

[Sapientoni]

I refurbed my '81, had the cams ground to euro specs, added Martin Schneider headers, went to Charlotte Motor Speedway D.E. was 5 mph slower down the backstraight, but when the mufflers were off, everybody thought it was a nascar stocker. Loudest DB award for the event. Wasnt any faster with the headers opened, bummer with $500 purchase. I'm thinking of putting them on my '86 for a back to back test to see if factory got it better first. For sure factory won't burn out like the steel MS headers did...twice. Had pics of them on here once when I wanted to sell them.

[Sapientoni]

AND, beside the won't fit 3 bolt '87's, you can't take the '87's off the engine without jacking it up like you can with the '86 and earlier.

[Zimoludek]

Hi, I have an 79 928 US version 4.5 and I just recently got an 85/86 Headers for it when I look at the old 79 headers I see there are some hoses connected to them plus one kind of bigger half inch line. How do I make this work with the 85/86 I really need help with this, my mechanic after changing my oil gasket connected the new headers and he welded a piece of pipe to connect it with the rest of the exhaust. Ever since the engine runs like **** it deals and it feels like timing is off, does anyone know if the missing vacuum lines have anything to do with how it runs now?