black944er

what do you guys think of the stage 1 kit from Carl ? anybody installed this one. I like the look and as it runs without an inter cooler the installation might be easier. any thoughts?

SQLGuy

I am in a similar situation: deciding between Stage 1 kits for my '88 5-speed.

Any new thoughts or information to share? I have spoken to Carl, and gotten some email information from Tim, but am still gathering data.

One additional consideration for me is that I'm at 6000 feet elevation and would like a bit more low range boost, if possible, to help offset altitude losses.

Thanks,
Paul

Cosmo Kramer

Low range boost with a centrifugal supercharger is going to be tough to get especially at high altitude. That said, Tim's kit is well designed and can be easily upgraded if needed.

Another option is a rear mount turbo, a member here installed one with good success, I believe his kit is this one here.

http://www.p9-m.com/rmt928.html

SQLGuy

I would have thought turbo would be even worse for low range boost. No? Tuomo (sp?), has a twin turbo setup, but he's at sea level (VA).

Sounds like you're suggesting the roots type kit? Any experience with that one?

Cosmo Kramer

The roots kit is only available through 928 Specialists and I am not sure if they are shipping them currently, however they are very nice setups.

The Rear turbo does come in at low RPM, read Killav's thread and it will give you an idea as to how it performs.

https://rennlist.com/forums/928-foru...kit-001-a.html

AO

Yep... It's a nice kit. Tough to get.

SQLGuy

Hmm... read through Killav's thread. He has an auto, so can play a bit with the torque converter to "pre-spool" the turbo. Doesn't sound, from this, that he's getting that much low-end boost, though:

"Anyone that has any reservations about turbo lag with a rear mounted turbo need not worry. There is virtually no lag. The torque of the V-8 gets things moving along very nicely before boost hits at 2300 or so and is all in by 2600-2700 rpm give or take a few."

SeanR

You don't have to worry about turbo lag, these are not cars that have 90hp and then suddenly you have 250hp. The mid mount turbo car I did (5 speed) is just unfreaking believable on power. Really no way to describe it.

The power on is very smooth and just continually builds up to scary fast. The tires have a hard time even getting grip in 3rd gear at 3500 rpm.

I used to be a proponent of going super charged, and have since changed my mind. I will be going turbo.

Cosmo Kramer

Yes having the boost "all in" at 2700 like Killav said is way better then any centrifugal supercharger. I am barely crossing 0 vacuum at that point.

killav

I am the member that installed an RMT on my car. I really like the power delivery of this system. The torque that the turbo produces down low is nothing short of amazing. Turbo lag is just not present on this system (on my car anyway). I want to make it clear that I have modified my stall speed by 400 rpm or so. This does have a positive effect on leaving from a dead stop. I just step on the gas to flash the converter, and I am off like a rocket, tires ripping loose, intake already under positive pressure. The pedal is not to the floor at this point either. If I do that, it just goes up in tire smoke and quickly ****s to second by itself and I go nowhere. Not sure why it does this because I thought as long as I manually had the transmission in low gear it would just bounce off the rev limiter but it doesn't. It shifts to second on its own at 6200rpm or so.

killav

Another oddity, is that I do not have limited slip, but if I line the car up straight, both tires do spin for a while, but eventually I just have a one tire burner if I stay in it. The car gets sideways every time from a dead stop when launching. My car does not have option code 220.

AO

Mike-

I don't recall, did you make it to the dyne since your install? Curious what the RWHP and the TQ curve look like.

andy-gts

I for one was unhappy with centrifugal boost......tooo much into rpm to really get usable hp . I dont want to live at 4 k to feel the power. I waited 18 months for a twin screw from DR at 928 motorsports....The man just doesnt like money i guess...
If some one else could jump in and make a twin screw for our cars, now that would be awesome. lots of power without living at 4-4500 rpm just to get 5 psi.
Man I want a twin screw sc really bad!!!
andy

SQLGuy

Hi Andy,

Which kit are/were you using? Also, was it on an auto, or manual?

Thanks,
Paul

SQLGuy

Can you give more detail on whether you're getting any benefit in low-end torque or drivability from your system?

Also, what year car, and what transmission do you have?

Thanks,
Paul