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And oh yeah...one more thing about the cost of the headers/exhaust (true story)...
Your Armani suit...$1,500. Dinner and drinks for two at the Capital Grille...$300. Valet parking for your new S Class S63...$20
And while getting your car...the look on your face when your stripper girlfriend stops in mid sentence while you're talking...and turns away just to listen and stare at my car as I slowly drive by...
PRICELESS...
Got mixed feelings about that story. My 928 has a pretty mean exhaust sound (https://picasaweb.google.com/lh/phot...eat=directlink), but my bone stock E63S station wagon isn't too far behind. They made that V8 a little quieter in the S-class, I think.
With the turbo car, I get Porsche drivers stopping and chatting with me at the gas station. With the E-wagon, I get the most attention from the snowboarding guys with pants hanging at their knees. The S65 Coupe, which has a much smoother exhaust note than either the E63S Wagon or the 928, gets the most attention from 50-something men.
None of my cars seem to get any sort of reaction or even any attention from any females, maybe that's just New England vs. Texas thing. You can't get an Armani suit here for $1500 either...
That has a great throaty sound, too...Don't get me wrong, the S Class are extremely nice, classy cars...and clearly, this was an isolated incident that was just funny enough to share. And I think it was only because (at least in this part of town), new luxury sports cars are ubiquitous, and 928s sometimes stand out only because they are something different...
In my short period of ownership, 99% percent of random comments have come from men that are gearheads...Always a nice conversation, and a chance for me to learn about whatever they are driving...
And regarding the suit...a WAG for sure...definitely not something ever in my price point to consider...
No one is going to ever get a 30hp increase by Sharktuning an S4 that is well tuned to start with.
10hp is a lot to expect.
Porsche simply did not leave that much on the table. They equipped these engines with knock sensors, which automatically retard the timing when knocks are present (which allowed them to run near maximum timing) and ran them a bit rich at WOT (and the S4 engines are not sensitive to running anywhere from about 11.5 to 12.5.....so running them rich lost very little power.)
Now if you've got other associated problems that you discover when you are Sharktuning (bad MAF, bad knock sensors, bad hall sensor, leaking dampers or fuel pressure regulator, no full throttle switch, throttle doesn't open all the way) that is a different story.....your car wasn't well tuned to start with.
Well Greg, its seem im living the dream. I took the Stockish S4 with all stock stuff on and the only thing non stock, was no cat installed in a stock exhaust system, and the GT cam., and got 45hp gains. 290rwhp to start going to 335rwhp in 1 week of mods... including:
Level II headers
3.5" single pipe exhaust with borla muffler
fuel pressure increase
vented air box
MAF screen removal
KN
2 disc clutch conversion
no other changes.... Note the fuel changes going from 10:1 near 6krpm to 12:1. 10hp loss.... so there IS a change in HP for fuel ratio changes.
as a note.. this car was in great running condition to start. I would say , the better the condition of the engine, the better the gains that the headers will provide as well as other flow changes. I didn't do much special here, but the gains were solid and they lasted for 8 years before this engine came out of the car after 120race days! the lowest the engine ever made was 300 when I changed to 85cams. once I dialed them in timing-wise, the HP went back to 320rwhp. Never again as high as the Holbert cams, but that could be age of the engine or the cams performance up top.
You are not exaggerating at all! (Not that I've driven a lot of other 928's)...
Every time I get a chance to drive it, at least one random person stops and asks about the exhaust and the car...Again, my sincere thanks for everything...
For those on the board, I haven't posted yet about the car, the headers/exhaust, Greg's other modifications, Sean's new wiring harnesses, etc...unfortunate and unexpected work/family/life curve ***** had me sidetracked...
Anyway...the bottom line...the art and genius of the design of headers/exhaust totally transformed the car...In addition, Greg designed fuel injector adapters (now sold as a kit) that allows the use of new 24 lb. 4 hole injectors...And coupled with swapping the ECU for a US 85/86, and a thorough Sharktune...If I recall correctly, Greg mods added at least 35 rwhp to the dyno results...
Personally, I think the significance of his fuel injector adapter invention has been extremely overlooked here...With the euro injectors NLA, the only choice was to cross fingers and hope all the old ones could be successfully serviced by Witch Hunter...no other options...until now...
Anyway, lots more to follow in a separate post...but again, I am extremely grateful the help I have received from Greg, Sean, and Roger.
Respectfully,
Rich
You've got every reason plus about a dozen others to post and brag about your car. It's a special one and one that would not be as it is if you were not willing to pump the $$ to make it in to a one of a kind vehicle Rich. Seriously. This is almost a one of one deal here. There isn't a single on like this in the states and I feel honored to be advancing it as a machine. So thank you on that.
You've taken an '85 Euro to a point HP/TQ wise that no one else has at this point with out putting forced induction on it. Hope you don't mind if I drive it a few days to "test it out" before you pick it back up. BTW, the A/C is looking 110% as of today and plan on getting the rest buttoned up Sunday and Monday.
That has a great throaty sound, too...Don't get me wrong, the S Class are extremely nice, classy cars...and clearly, this was an isolated incident that was just funny enough to share. And I think it was only because (at least in this part of town), new luxury sports cars are ubiquitous, and 928s sometimes stand out only because they are something different...
In my short period of ownership, 99% percent of random comments have come from men that are gearheads...Always a nice conversation, and a chance for me to learn about whatever they are driving...
You need to do a thread on your car, I didn't find one when I searched.
Mark , So how dose the HP gain you got ( I P/U 31 HP with headers and exhaust ) relate to Greg saying that sharktuning will not will not P/U 30hp on well running S4 ?
30 rwhp from the combination of new exhaust including headers and sharktuning for an S4 is completely believable number. I mean you have to get it right, but it's a good target to shoot for.
I've spent some of my time and also a lot of computer time trying to understand what's happening with the 928 exhaust. This was in relation to the turbo project, but I believe the following also applies to normally aspirated engines.
At low rpms, the header primaries have to be long enough to delay the 180-degree interference pulses such that they don't screw up the overlap of the victim cylinders. That is, firing order is 13726548. The 180-degree interference relations are 2->3, 6->7, 8->5, and 1->4. The longer the path for the pulse to travel between those cylinders, the lower the rpm at which the overlap starts working well.
At high rpms, the main problem is the 90-degree exhaust interference. The relations are 3->1 and 5->6. All four cylinders can have elevated pumping losses and in addition 1 and 6 are prone to high-rpm knock. There are many approaches to dealing with the 90-degree exhaust interference, two of which I believe work. The first approach is to join 1&3 and 5&6 as close to the exhaust ports as possible and then step up the pipe size. Shorty headers should be built that way. The second approach is to make the pulse travel distance between those cylinders very long, such that the pulse from 3 (and 5) arrives at 1 (and 6) after the exhaust valve has closed. Long-tube headers work this way. The in-between shorty headers, including the 928 S4 stock exhaust manifold/header, is neither fish nor fowl. Therefore, there's room for improvement either with a shorty manifold configured like Ford Coyote's exhaust manifold or with the usual 4-1 or 4-2-1 long-tube headers.
The benefits grow with the increasing overlap of the cams, I believe.
I am half tempted to order custom shorty headers to prove this out on a dyno.
30 rwhp from the combination of new exhaust including headers and sharktuning for an S4 is completely believable number. I mean you have to get it right, but it's a good target to shoot for.
I've spent some of my time and also a lot of computer time trying to understand what's happening with the 928 exhaust. This was in relation to the turbo project, but I believe the following also applies to normally aspirated engines.
At low rpms, the header primaries have to be long enough to delay the 180-degree interference pulses such that they don't screw up the overlap of the victim cylinders. That is, firing order is 13726548. The 180-degree interference relations are 2->3, 6->7, 8->5, and 1->4. The longer the path for the pulse to travel between those cylinders, the lower the rpm at which the overlap starts working well.
At high rpms, the main problem is the 90-degree exhaust interference. The relations are 3->1 and 5->6. All four cylinders can have elevated pumping losses and in addition 1 and 6 are prone to high-rpm knock. There are many approaches to dealing with the 90-degree exhaust interference, two of which I believe work. The first approach is to join 1&3 and 5&6 as close to the exhaust ports as possible and then step up the pipe size. Shorty headers should be built that way. The second approach is to make the pulse travel distance between those cylinders very long, such that the pulse from 3 (and 5) arrives at 1 (and 6) after the exhaust valve has closed. Long-tube headers work this way. The in-between shorty headers, including the 928 S4 stock exhaust manifold/header, is neither fish nor fowl. Therefore, there's room for improvement either with a shorty manifold configured like Ford Coyote's exhaust manifold or with the usual 4-1 or 4-2-1 long-tube headers.
The benefits grow with the increasing overlap of the cams, I believe.
I am half tempted to order custom shorty headers to prove this out on a dyno.
If I understand most of the post I've read from experienced tuners, the upgrade from stock hexausts to headers (in a S4) will necessitate retuning the ECU for fuel delivery & ignition timing. Some advocate adding new injectors (bigger I suppose...) in the addition of headers (there seems to be better ones suited for the S4 engine, others for S2 (4.7 Euro 16v)) engines). Anyway, all these approved & tested mods have their pros & cons regarding to suscribers, but, as I find out, there's a positive HP gain with the addition of hdrs, it's a quetion of how much someone is willing to spend ($ Vs $$ VS $$$...) The cons are mostly in regards of practicality for the daily driver, compared to racing & tracking needs. The biggest point being the difficulty encoutered by less experienced owners in regards with mechanical knowledge. The other point that was enlighted was the problems related to heating & dissipation common with headers (a problem that does'nt really concern racers in a certain degree, since the goal is to be lightweighted & to get rid of everything not essentially needed around the exhaust).
Here's my point of view regarding this mod. I think I would probably be tempted later if I decide to port the head, change injectors, modify the MAF, etc...If I would have bought a 16v (manual...) instead of a 32v, I probably would have jumped on this mod with-out questions, but I think, for practical reasons, that I will stay with the stock h-manifold for the moment & climb up the latter one step at the time & probably swap the cats with an X-pipe (anyone got one for sale cheap???) and also change that horrible duck beak muffler (don't know what passed through the head of the designer...!!!) for a good FF muffler. Next power-adder mod will probably be a good reliable SC
Any advice on X-pipe (hp, quality, stainless vs mild stl, etc...)
Thank's for all your stories & expertise, I really appreciate it!!!
Once you have done this mod (including TB plenum and pre-TB air splitter - all simple stuff), and experienced the performance difference, I'll leave it to you to decide how much you really need expensive headers, cams etc. If, however you decide keep going, this mod will provide a very strong 'breathing' foundation on which to build.
Yes - I know it means removing your manifold. PITA. I know this.
Yes - I know ii means finding someone adept with his hands - say at a hobbyist level. Maybe even you. If you were any good at shaping play dough as a kid then you'll have no trouble. :-)
Yes - you'll have to trust me at my word re performance benefits.
Yes - will help you every step of the way. It's really not that hard btw.
But - you must exactly copy what I have done - ie don't chop this or change or that 'cos it seemed like a good idea. (Based on what?) ):-(
I didn't arrive at my configuration by accident ya know. (Many hours of CFD research behind this. (Computer Flow Dynamics)).
If you you want to make 'improvements', then wait until U have this manifold delivering first, then do so at your own risk.
No - I have nothing to gain financially c/- this mod. (A patent at the time would have been good ).
Reality: with a few 'useful' 928 buddies you could knock this over in a weekend. If U thought it through, all of you could achieve the mod in that same weekend.
Then you would have a 'few' ppl with big wide grins on their faces, asking "where has this HP been hiding all this time?".
PS: when The Black Dog let's me get the Shark running again, I'll video a 0-60 mph run.
Already I know that should I 'deck it' in 1st, I can't shift quickly enough into 2nd before reaching the rev limiter, and almost as quickly from 2nd to 3rd.
So here and now I'm going to stick my neck on the block: a 1/2 second drop in 0-60mph time. Doesn't seem like much, but wait until you do a 3rd gear roll on from 50 mph: ear-to-ear grin won't even come close.
No joke - this will have you questioning your need for $1000 headers and $2000 cams.
Never mind. Whatever floats your boat. :-)
Anyway I'll leave it with you.
BTW - materials cost is about $50.
UpFixen.
Last edited by UpFixenDerPorsche; 11-22-2015 at 10:44 AM.
Interesting...what did you actualy do?? Look's like you added GB Weld and fill-up the gaps and rounded the edge...& why the oven??(look's like a modern art museum sculpture... )
Comparing to the simple layout of the 16V spider, it seems like there is a lot to be gained in the inlet manifold of the 16V engines. Any ideas or experience?
Once you have done this mod (including TB plenum and pre-TB air splitter - all simple stuff), and experienced the performance difference, I'll leave it to you to decide how much you really need expensive headers, cams etc. If, however you decide keep going, this mod will provide a very strong 'breathing' foundation on which to build.
Yes - I know it means removing your manifold. PITA. I know this.
Yes - I know ii means finding someone adept with his hands - say at a hobbyist level. Maybe even you. If you were any good at shaping play dough as a kid then you'll have no trouble. :-)
Yes - you'll have to trust me at my word re performance benefits.
Yes - will help you every step of the way. It's really not that hard btw.
But - you must exactly copy what I have done - ie don't chop this or change or that 'cos it seemed like a good idea. (Based on what?) ):-(
I didn't arrive at my configuration by accident ya know. (Many hours of CFD research behind this. (Computer Flow Dynamics)).
If you you want to make 'improvements', then wait until U have this manifold delivering first, then do so at your own risk.
No - I have nothing to gain financially c/- this mod. (A patent at the time would have been good ).
Reality: with a few 'useful' 928 buddies you could knock this over in a weekend. If U thought it through, all of you could achieve the mod in that same weekend.
Then you would have a 'few' ppl with big wide grins on their faces, asking "where has this HP been hiding all this time?".
PS: when The Black Dog let's me get the Shark running again, I'll video a 0-60 mph run.
Already I know that should I 'deck it' in 1st, I can't shift quickly enough into 2nd before reaching the rev limiter, and almost as quickly from 2nd to 3rd.
So here and now I'm going to stick my neck on the block: a 1/2 second drop in 0-60mph time. Doesn't seem like much, but wait until you do a 3rd gear roll on from 50 mph: ear-to-ear grin won't even come close.
No joke - this will have you questioning your need for $1000 headers and $2000 cams.
Will this affect the performance shops offering cam and header products? Naaah. Why? Cos the more you spend on your ride (for about a poofteenth performance gain) equates to manly spending ability on all sorts of big hunky shiny **** at these shops, and then being able to wear the $$$ total later as a He-man badge.
IMHO, the loudmouth know-all's on the forum will be the last to venture down this path (simply because they know everything there is to be known), while I would expect the more considered, thoughtful, and analytical souls to venture into this idea.
Never mind. Whatever floats your boat. :-)
Anyway I'll leave it with you.
BTW - materials cost is about $50.
11-14-2015, 10:32 AM
) and also change that horrible duck beak muffler (don't know what passed through the head of the designer...!!!) for a good FF muffler. Next power-adder mod will probably be a good reliable SC
).
