K27 HF2 Question

[les_garten]

Hello,
I just fitted a K27 HF2. Nice Turbo! I was wondering where boost starts and where it is full on for most folks that have one of these? I had a K27 7200 before and it seems like I lost about 500 RPM. I kinda expected it though.

Les

[David]

Mine's pretty much full boost at 3500, but it's climbing fast at 3000.

[les_garten]

Originally Posted by 125shifter

Mine's pretty much full boost at 3500, but it's climbing fast at 3000.

Thanx! I noticed your sig there. I have a '92 R100RT

Les

[David]

Originally Posted by les_garten

Thanx! I noticed your sig there. I have a '92 R100RT

Les

Something else I can blame Pelican for .

I always loved the boxer engine, so I bought it when my 930 was down so I had something to go fast on. I think my car's faster now!

[les_garten]

Originally Posted by 125shifter

Something else I can blame Pelican for .

I always loved the boxer engine, so I bought it when my 930 was down so I had something to go fast on. I think my car's faster now!

Mine's the last year of the classic boxer. I rode one like yours before, and it's considerably more civilized than mine is, yours is a lot smoother and the EFI is very nice.

I punched my motor out to 1100, bigger Intake and Exhaust valves. Little more compression, lightweight wrist pins. Satge 4 Flowed and CC'd heads, Dual plugged, balanced and blueprinted motor, Cam'd, high ratio Crane Forged AL rocker arms, 40mm Mikuni Flatslides and some more I probably forgot about.

When I wick my throttle, the bike pulls a wheelie and breaks the rear tire loose. Definitely a serious Old R-Bike. Need to do some fairing and Paint on it presently due to a crack in the fairing from a low speed drop.

Thanx for the info!

Les

[David]

Sounds like a cool bike. I worked at an independent BMW shop in Austin in school that built some pretty wicked boxers so I've had an appreciation for them for a while.

Ever so often the idea of going a little wild on the engine crosses my mind, but fortunately the idea fades pretty quickly.

[les_garten]

Originally Posted by 125shifter

Sounds like a cool bike. I worked at an independent BMW shop in Austin in school that built some pretty wicked boxers so I've had an appreciation for them for a while.

Ever so often the idea of going a little wild on the engine crosses my mind, but fortunately the idea fades pretty quickly.

I drove my 930 and laid into the boost for the first time today with the HF2. Man, it's nice to feel the tires bust loose again! When my 930 was stock, after a few years of driving it, it just didn't have the same performance. I asked the guy who was wrenching my car, he said it feels like a stock 930. But it didn't for me.

When I decided to rebuild it and tore it down, every compression ring on all cylinders was broken. They just fell out in a zillion pieces. It was amazing how well the car ran with smashed rings. I have an adjustable boost controller on it at the time and am sure that didn't help anything! Even with all the rings broken the cylinders and pistons were perfect.

Les

[Craig 930 RS]

EFI perhaps needs adjusted? Just a dumb non-EFI guy guess.

[Craig 930 RS]

P.S. If you want a real treat, go to Les' rebuild pictures http://www.lesgarten.com/pix/porsche/
Great stuff, Les!

[les_garten]

Originally Posted by Craig 930 RS

P.S. If you want a real treat, go to Les' rebuild pictures http://www.lesgarten.com/pix/porsche/
Great stuff, Les!

Craig,
You must have a screaming Internet connection to DL those PIX. I made most of them pretty big for detail.

Thanx for the compliment. Wayne Dempsey, His Book, and Pelican parts made it possible for me to do this.

Les

[David]

It is nice having all that boost isn't it .

I just feel a little bad for my fellow motorists. Can I help it if my car wants to lay down big long black streaks when I'm passing .

[les_garten]

Originally Posted by 125shifter

It is nice having all that boost isn't it .

I just feel a little bad for my fellow motorists. Can I help it if my car wants to lay down big long black streaks when I'm passing .

The Car corrupts the driver!

Les

[JFairman]

I live in West Palm, and have a venetian blue '87 930.
I also have a '75 BMW R90S that is bored to 980cc, dual plugged, CC products lightened flywheel and high lift rockers, and Ti valve spring retainers.
It still has the origonal 38mm dellorto carbs with different mixture needles and main jets.
It also has a CC products cast upper triple clamp, braced swingarm, 40mm stainless dual exhausts with supertrap mufflers, telefix lower fork brace, progressive suspension front springs and koni's in the back.

Unfortunately it and a Honda 500 intercepter have been in storage for a while now and I havn't ridden them in years.

I was driving south on US 1 in Tequesta around the first week of november and sitting at the light at county line road and some one came by in the right lane and turned right onto county line rd.
The guy driving seemed enthusiastic about my 930 and I have wondered if it was someone that might be on this message board.

[WydRyd]

Originally Posted by les_garten

had a K27 7200 before and it seems like I lost about 500 RPM. I kinda expected it though.
Les

Remember, the larger the compressor wheel = the more inertia = more lag. However, you'll be able to flow more power up top and the turbo won't run out of "puff" in the upper RPM band.

[les_garten]

Originally Posted by JFairman

I live in West Palm, and have a venetian blue '87 930.
I also have a '75 BMW R90S that is bored to 980cc, dual plugged, CC products lightened flywheel and high lift rockers, and Ti valve spring retainers.
It still has the origonal 38mm dellorto carbs with different mixture needles and main jets.
It also has a CC products cast upper triple clamp, braced swingarm, 40mm stainless dual exhausts with supertrap mufflers, telefix lower fork brace, progressive suspension front springs and koni's in the back.

Unfortunately it and a Honda 500 intercepter have been in storage for a while now and I havn't ridden them in years.

I was driving south on US 1 in Tequesta around the first week of november and sitting at the light at county line road and some one came by in the right lane and turned right onto county line rd.
The guy driving seemed enthusiastic about my 930 and I have wondered if it was someone that might be on this message board.

Hi,
Wasn't me. I had the Motor in my Beemer done by CC products. I just took off the 2:1 supertrap off of it and bought some Keihin's for it, haven't put them on yet.

Good stuff here.

Les

[les_garten]

Originally Posted by WydRyd

Remember, the larger the compressor wheel = the more inertia = more lag. However, you'll be able to flow more power up top and the turbo won't run out of "puff" in the upper RPM band.

Hi, Actually after stopping up some leaks and tweaking around with it, I'm not sure I lost as much as I thought. Maybe 2-300 rpm. Definitely breathes better than the K27 7200 I had in the Midrange and up top. Very happy with it. I need a boost pipe for it though. I still have the AL adapter and it's got to go.

Les

[RarlyL8]

Les, If you're using a C2T intercooler I have a stock up-pipe I'll sell. Shoot me an e-mail.

[les_garten]

Originally Posted by RarlyL8

Les, If you're using a C2T intercooler I have a stock up-pipe I'll sell. Shoot me an e-mail.

Hi RarlyL8,
I have an Andial(Garrettson) IC. My stock boost pipe is close. I have a few problems though.

1) I don't like the AL adapter with 2 O-rings seals in play with the K27. The first K27 I wittled the throat of, I ground off more than the present one.

2) I have a 3.2 Manifold, cut and flipped, so the angle from the outlet throat of the IC to the Throttle Body is a little different than stock. This makes the stock boost pipe have a slight gap at the top and bottom. I just don't like the O-ring seal deal. I would prefer big SS hose clamps and silicone hose transitions.

Les