techchallenged

I just purchased a '91 Turbo and wanted to know the best recommended performance modifications. My discussions offline have been to add a 1.0 bar spring, new exhaust w/catalytic bypass, and a k-29 turbo. What are your thoughts? I was looking at B & B exhaust, but cannot locate a k-29 turbo. I have located some posts on other sites for preference of the k-27 - 11 turbo for lower range. Any recommendations? Thanks!

biglicks

Welcome.

I've just done the same (ie bought a 91 turbo) luckily I already had a 1bar spring. My personal thoughts have been to get used to the car first before I start toying with it. I want to be happy I haven't bought an inherant fault I need to put straight before I use my cash elsewhere.

Is the car 100% standard, mileage etc, this would make it easier to give feedback? You might consider sorting the handling 1st of all, a good set up will help you manage any extra power you go for.

Good luck
Steve

tjr

Steve is spot on with his advice, get used to it first and sort out any underlying issues first (I guarantee there will be some) before you start modding it. Again as Steve suggests, most people seem to start by lowering their cars, often using H&R springs (and often with Bilstein Sport/HD shocks) or the go the whole hog and get adjustable coilovers (like Bilstein PSS9s). The H&R springs will set you back around $500, Bilsten Sport/HD shocks around $1k and coilovers around $2k.

The K29 is very old technology now. As you will have seen if you search for K27, many of us use the Ultimate Moterwerks K27 HFS instead.

If you have freer-flowing headers (B&B seems to be the best choice for performance although some people have had fitment issues), no cats, a K27 HFS (I'd add a Tial 46mm wategate too) then you should get around 360-370bhp.

Cost-wise you're talking about:

c.$2k for B&B headers
c.$1k for cat bypasses/new muffler
c.$1.5k for K27 HFS
c.$500 for the Tial

Plus probably around 5 hours labour if your exhaust system is not rusted on, or double that if it is.

Make sure your clutch is newish as the extra power may make it start to slip if not. If it does need doing, check your flywheel too - some people look to change it for a lightweight version even if it's sound. Clutch and flywheel is probably around $1.5k in parts and around 10 hours labour.

Before you do any performance mods I would recommned getting a thorough check of your engine's health with a leakdown and compression test. Many engines (although not all by any means) will need attention (top end rebuilds) at around 80k-100k miles - they seem to cost around $10-$15k depending on who does it and what needs doing.

I'm having most of this done (including the top-end) as we speak!

Finally good luck and enjoy!

Tim.

eyue

How much HP increase after changing to a K27 HFS ? Are they at the high end or middle ?

911addict

From standard, upgrade the suspension and open exhaust. Then enjoy the sound and handling. If you need more go LW clutch. Only if you really need more and have deep pockets then modify further.

I ran my car with HFS and standard headers (but cat bypass, and g-pipe) and it was dyno'd at 355 bhp at the fly, at the top end. Its very linear and not as much 'feel' as the standard turbo though. Frankly not worth the effort.

To get the real benefits you need to do the headers in conjunction, then it feels really good! I'd expect total BHP to be 380ish now.

Headers? Yes very worthwhile but I had a NIGHTMARE with fitment on my B&B's. I'd suggest GHL as the fitment seems to be better, but do your own research.

The lightened fly is great for low end response and gear changes but heavier pedal.

And most important with all this, is find a garage who has experience of these cars and mods. Do not accept bullsh** and maybes.

Finally use this forum's "search" buttons.

PS: Welcome to the club, and we expect photos ;-)

911addict

Oh, and I forgot to mention, get a wastgate decat pipe it will make your car very loud & exciting but only on full boost.

techchallenged

Thanks to all for your responses. I can honestly say the car is in transit, but know it has been lowered and has upgraded 18" Speedline wheels. Not certain what brand of coilovers are installed, but will know more when I take to my mechanic. The car has just over 92,000, and the previous owner just had a $15,000 rebuild done with new clutch. I will receive paperwork and be able to determine if it is a lightweight clutch. I currently have a '90 C2 Cab and have had a few 944's, so agree I should get comfortable with the power first. I just want to start planning and budgeting for future mods. And, if a sale or local dismantler comes up with something cost effective, I can start stocking up. I believe I will remove the cat and install a new spring immediately. If anyone has any further suggestions I would like to hear them. Thanks again!

dholling13

I would do the following:

1. B&B headers and muffler with wastegate pipe
2. Tial gate w/ .8 bar spring
3. High Flow S turbo
4. BMC filter kit
5. JIC Cross suspension if you aren't happy with the current suspension

I would strongly recommend Stephen Kaspar's shop for a place to shop.

Good luck and show us some pics after you get the car

dholling13

This unit IMO is as nice as the Garrett products especially for a modest set up. I would estimate 50-75 HP depending on headers.

dholling13

The B&B system has held up just fine for a lot of board members. Mark is just a little bitter