Help/Opinions on HP-Increasing Upgrades

[Norm K]

As we move deeper into another Rocky Mountain winter I'll be pulling the engine from the `80 930 I've owned for about a month and a half now to do a bit of re-sealing and some basic performance upgrades. Other than a K27 turbo upgrade a few thousand miles ago the car is bone stock.

The day after I got the car I had a new set of tires intalled, which improved things noticeably. Followed that by installing new front and rear Bilsteins and getting a proper alignment. Big difference in driveability.

In addition to the shocks, I ordered a bunch of stuff from our forum host; various seals and gaskets (about every one I could identify), chain tensioner collars, spark plugs, cap, rotor, shifter bushings and probably some basic items I'm forgetting at the moment. Also picked up a very clean Borla muffler from TT Surgeon.

In the interest of saving some money (and perhaps before I'd done enough reading here) I purchased a GSF header kit from Albert a few days after getting the car. Subseqent reading here suggests that might not have made the best choice, as some seem to have strong (negative) opinions of the GSF - and similar - brands. Thought about selling them, going so far as to post them in the classifieds here. I thought about using the proceeds to help pay for some Rarly8 headers, but since my limited budget still has to absorb an intercooler upgrade (also leaning to Rarly8) there's simply no way to get the additional expenditure past the War Department.

So, opinions please, what should I do?

1) Keep and install the GSF headers and upgrade to the Rarly8 intercooler

2) Sell the GSF and buy a set of Rarly8 headers, and skip the IC for now

or

3) Something I haven't thought of - I'm certainly open to some positive dialog

Finally (for now, anyway) what might I expect, HP-wise from options 1 & 2 above?

I look forward to your comments and advice.

Norm

[Tt surgeon]

Sell the headers, get a good IC and install it, eventually grab a used set of ghl, fabspeed, BB , etc. They freq pop on the fs section.
You're gonna get a huge bang from just the IC and muffler in combo w the 27.

[RarlyL8]

When adding mods incrementally it is good to work from the muffler back as each mod will allow better breathing and all components to work even better. You have the muffler and turbo so now on to the intercooler and headers.
Intercooler choice has a lot to do with how the car will be used. If you live in a hot climate an IC will be much more useful than a cold climate. Same if you track the car. If adding larger boost spring then an IC is more important. Performance is not increased but rather it is not taken away which is what happens when a small intercooler gets heat soaked or cannot handle the heat load on a hot day or from prolonged runs at increased boost level.
Short tube headers will add ~35WHP and my tuned headers ~50WHP. Both reduce lag by~500rpm.

[Norm K]

While I don't live in what might typically be defined as a "hot climate" I'll normally drive the car in relatively warm temperatures (between 60 and 100 degrees) with fairly low relative humidity. Don't presently expect much, if any, appreciable track time. Given this, should I expect an intercooler upgrade to help enough to spend the money ahead of other items?

Clearly I'm new to the Porsche thing and to the world of boost (of which I'm quickly growing fond) so I have a lot to learn. Fortunately, I've been wrenching for over forty years now; when I was a kid if you wanted to drive your car you damn well better be able to figure out how to fix it, and over the decades have become a pretty capable shade tree mechanic (except that my tree has morphed into a nice garage with a good assortment of tools).

Anyway, here's an example of my Porsche/boost naivete; in taking a look - without removing the bumper (or even the valance) I can't get a good look at the muffler. Pretty sure, though, that the car still retains its original euro-exhaust set up as there appears to be no catalytic converter. What puzzles me though, is that the muffler appears to contain an outlet that leads to the wastegate. If this is the case how would I go about (what oughta be the simple task of) installing the Borla muffler? What to do about the wastegate?

Are the euro exhaust manifolds superior to the US versions from a standpoint of breathability and, if so, would it make sense to just hang in there with them for awhile?

I've searched a bit for a schematic of the euro exhaust, but my inherent laziness and the search function's limitations have prevented me from finding much.

Sorry for such elementary questions but I'm trying to make reasonably decent decisions.

[RarlyL8]

You probably have a muffler similar to this one:




A stubby WG dump pipe or OEM WG muffler can replace the muffler plumbing:




Yes the "Euro" system is much better than the "USA" system. You can expect about 500rpm drop in lag and 35-50WHP increase when switching to headers. In terms of performance bang for the buck headers win out over a large intercooler unless you live in a warmer climate (read South or Southwest US) where a larger IC is good insurance to fight detonation and power robbing heat. You will eventually want both.

[Norm K]

[QUOTE=RarlyL8;7167473]You probably have a muffler similar to this one:

Yup, that's the one.


A stubby WG dump pipe or OEM WG muffler can replace the muffler plumbing:

Standard bolt pattern?


Yes the "Euro" system is much better than the "USA" system. You can expect about 500rpm drop in lag and 35-50WHP increase when switching to headers.

If the Euro system is much better than the USA one would the anticipated hp gain still be 35-50, or something less?

If I can get my GSF system sold I'll take the proceeds, combine it with remaining budget and buy a set of your headers. Fingers crossed that someone's looking for a brand new budget-priced header kit for a couple of hundred dollars less than they can buy it for anywhere else.

[RarlyL8]

Some folks do have good luck with bargain price headers, it seems to be luck of the draw. Metallurgy and welding are what you pay money for. Cheap metal and cheap welds generally won't last long behind a glowing red turbo.

The "USA" OEM exchangers were good for 265HP while the "Euro" put out 300HP. Replace a Euro exhaust with my headers picks up ~50HP. Replace a USA exhaust with my headers picks up ~85HP. Yes you read that correctly. I am a hero whenever we replace a USA system, ha! Baseline and test data is also with my muffler in place, you can't cork it up or will lose ~12WHP with any system.

[Norm K]

Originally Posted by RarlyL8

Baseline and test data is also with my muffler in place, you can't cork it up or will lose ~12WHP with any system.

Well, can't do it all (at once, anyway) so I'll have to stick with using your headers in conjunction with the Borla muffler I already have. Hope the Borla's not too much of a "cork".

Will you be available on the 26th? I'd like to give you a call, chat and see about getting some headers on order.

nk

[RarlyL8]

Yes, I'll send you an email.

[timspu]

NK,

You are making the best decision going with Brian. You will actually save money in the long term my getting it right the first time.
Enjoy your mods.

Tim

[aseem]

Originally Posted by RarlyL8

Yes, I'll send you an email.

Hi Brian. I sent you an email a few days ago (brian(at)rarlyl8.com) about an update package. Thought maybe you were off for Chrismas.....

whenever you have time to look at it....