BAE turbo kit - which turbo ?
 

I got a BAE turbo kit that I am considering to use on my 80SC. The kit came without a turbo. Anyone out there who could tell me what turbo will fit with the BAE kit ? The intention is to run it at 6 psi or so, without an intercooler. I have stock 9.3:1 pistons and will use either SC cams or DC13 cams currently in the engine. Usage is street and I am aiming at early spool up

Grateful for any advice

Mine came with a Rayjay. T04B? Try a search here. Example:
http://forums.pelicanparts.com/porsche-911-technical-forum/90065-911sc-turbo.html

Other factors besides fitting to the engine - mainly engine longevity. Review this to avoid engine issues with added boost:

Maximum Boost: Designing, Testing and Installing Turbocharger Systems (Engineering and Performance): Corky Bell: 9780837601601: Amazon.com: Books

Sherwood

Hei trond,

The turbo that came original with the bae kit is an old turbo. Will not recommend using it anyway.
you should look for a newer type ball bearing turbo like ie garret gt28r. Maybe even smaller to make it spool faster.
All depending on your hp goal. But with 0.6 boost, you are probably at 300hp

Trond

Hi

I would not use the old (Rayjay, I believe) turbo either.

I would use a borg warner S256 or a garrett 2871RS. Considering money as well, I choose the borg warner.

I found the BW S256 with T4 flange which is what I need. However only with hot side A/R 1.00, 1.15 & 1.22. I have seen other posters discussing less than 0.7 A/R for turboed SC

I picked up this on Borg Warner website; .... a smaller A/R turbine housing will be biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high back pressure, which can result in a loss of top end power. This type of engine performance is desirable for street applications where the low speed boost response and transient conditions are more important than top end power.

GT28r has T25 flange

I have been using the Rayjay T04B on my 2.7L running 6 psi of boost. It starts to come in right around 3,000-3,500 rpm and pulls all the way to redline. With the stock 915 transaxle, I don't know if it would be good for the boost to come in any earlier. The nice thing about your SC is you will still have all of the low end torque of the 3.0L until the boost comes in.

Lengthy threads started by rfong years ago addressed many DIY issues adding a turbo onto a 3 liter engine. He was my cousin, and I followed his goal of manufacturing a turbo kit for mid-year 911s. Unfortunately, he passed away a few years ago at too young an age and never got past several testing stages (and a couple of 911s). His last iteration was testing a compact intercooler inserted into the BAE system.

The compression rings on his first 911 eventually expired due to the added stress of boost. Not sure what that threshold was, but I suspect it was a combination of just a little too much boost (5-6 psi) on a mid-mileage engine and too many opportunities to surprise unsuspecting stop light heroes.

Sherwood

It is possible to fit an intercooler under the decklid without adding a tail, and I have found it to be effective, reducing head temps by just under 50F, typically.

I think the main problem with slapping a turbo on a CIS car is the upper limit on fuel flow through CIS. The 930 flows more, and even then modifications are made to extend it further.

I suspect my car starts running lean somewhere North of 5500 RPM, so I use the redline sparingly. I did lose the ring lands on one piston at some point, which led me to a new top end, but the car has been running flawlessly for years. Boost is about 5psi. Torque in the 250 ftlb range. Temps at 180F typically. Great for street.