Ketchmi

Yes David, we haven't had the website up for years. Our resellers do a good enough job keeping you guys supplied that we pulled it down.

You will see significant gains with just the X-pipe but PorKen is currently working on a chipset for the S4's also. The two combined are your best bang for the buck performance wise on any 928. You will see 20-30 rwhp gains and about the same torque with just the X-pipe. I know Ken is over 300rwhp with his chips currently but like me, he wants every last horsepower he can get out of them before he releases them.

Avar928

Same here. I felt much more pull throughout with the X-pipe installed especially at the lower end. I thoroughly enjoyed my 30mile drive back home from my mechanic even in stop and go traffic.

One of the local 928ers here was warned by the installer to be careful when pulling out when he got his X installed. When he left the shop he spun out on a turn from a stop underestimating how much lower end grunt was gained.

DKWalser

Dave - Any idea when the PorKen S4 chipset might be available? As for the X-pipe, picking up an additional 20-30 horses would be close to a 10% improvement. That would be noticeable. How does the switch affect emissions? Arizona isn't as difficult as California about such things, but we don't let just anything run on our roads, either.

Avar928

You'd have to ask Ken (Porken) regarding the S4 chip set. Still in trials, he has a thread he updates with dyno runs.

I believe if you have the stock cats you shouldn't worry about it. Without cats, make sure your car is running at top shape. With hi-flo cats, same thing make sure your car is in top shape and get the car nice and hot before going in for a check.

https://rennlist.com/forums/928-foru...-needed-2.html

Ketchmi

Well David, most of your questions were already handled. You can run the x-pipe catless or with our high flow cats. If you have emission testing then you have a couple of choices. You can keep your factory cats and swap them back when testing is due, takes less than 1/2 hour or you can install our high flow cats and not worry about swapping them out. And yes, it's a very noticeable seat of the pants improvement.

DKWalser

Dave - Since it's clear from another thread that I misunderstood what was said above (I thought the x-pipe could be run with the stock cats, one of your two versions of high flow cats, or catless), I hope you won't mind my asking for further clarification: Of the 20 - 30 rwhp gain, how much of that is available with high flow cats and how much of that is available running catless? My car will be subject to emissions testing for the next few years. With everything basically stock, last month the car passed AZ (Maricopa county) requirements with flying colors. I'd like to make sure things stay that way, so I'll be using cats.

One more question, any idea how much of the performance improvement comes from the x-pipe as opposed to the increased flow from the high flow cats? Not that it really matters; I'm merely curious.

ROG100

David we did dyno runs, with and without, high flow cats on three different cars with no measurable difference. All dyno runs same day, same ambient temperature and same dyno. I have high flow cats on my GTS as do many of my customers with 89 and newer cars. I am sure Dave will add the detail.

MjRocket

Roger

What does a set of high flow cats for an 87 run? Also when I bought my x-pipe from you I ordered it to be used without cats, so Im assuming I would just need to cut it down to add the cats in. Would this be correct?

Thx

ROG100

A pair of high flow cats are $360 and you cut down the existing pipes by 10.5" to accommodate the cats. You will need additional clamps.

MjRocket

Good price, and thanks for the info..I'll be in touch soon.

Thx

safulop

I'm waiting for Ken's S4 chips with bated breath. I have those performance chips whose name must not be spoken, and they suck! Tried replacing them with the stock chips so I wouldn't be running so rich all the time, but the stock EPROM copies I got didn't work, so my shop had to put the stupid Autothorities (oops, I said it) back in so at least my car is running. Wasted 2 hours of shop time on that effort, nothing accomplished.

PorKen please hurry!

-Sean

vsalvato

Guys, if I install an x-pipe (Supersprint likely) on my EU 1988 MYS4 am I likely to need an EPROM change and re-tuning or would it be the LH unit to adjust itself to the optimal set-up once the cats are removed? I am not looking for extra performances but I simply want to get rid of likely clogged and extremely heating cats which I am sure eat up 30-35 CV from my engine...

John Speake

If the engine breathes better when clogged cats are removed, then the MAF will measure the extra air and all will be well. It is possible to optimise the fuel map for less rich fuelling at WOT and also to compensate for the slightly weak mixture in the mid range (off loop).

FredR

I run with one of Louie's original x-pipes and have always been pleased with it but did I read somewhere that enhancements to the original design have improved the gains?

I am looking for thos elittle increments here and there - doubt that such a new design justifies the additional cost unless one can recover soemthing on the old unit but...?



Regards

Fred

NC928S4

That does it! An X-pipe and new CATs just moved to the top of my 2014 list. Brake overhaul will need to wait...