911SC (with CIS to EFI) Turbo Conversion
 

With the design phase of my CIS to EFI kit winding down I've started looking at the next stage....Turbocharging.

I am first going to build a prototype on my 1978 911SC which is running the CIS to EFI conversion and backdated heat exchangers. Once complete I'll look into the feasibility of a kit for others looking to go down the turbo path.

Here is what I'm starting with:

http://forums.pelicanparts.com/uploa...1080248103.jpg

It is a T04b turbocharger with a "V" compressor. The hot side has a 0.69 A/R. I think this is an OK starting point.
Here is the compressor curve:

http://forums.pelicanparts.com/uploa...1080249046.gif

i havnt got a f-cking clue if its a good or not but you've got to have maximum points for just being this involved with your turbo project!
im sure it will all work just fine.

keep up the good work

Andy, UK

If I were building from scratch again I would choose a TO4E in 54 trim as I prefer low end TQ to high end HP and lag at least for a 3.0L.

http://not2fast.wryday.com/turbo/maps/t04e-54.gif

There is a thread somewhere with you in it on all the selection criteria with pros and cons.

Actually if I was building from scratch again I would certainly consider a Garrett BB turbo.

Here is the thread with all the opinions....including yours. :)

http://forums.pelicanparts.com/showthread.php?s=&threadid=139379&perpage=20&pagen umber=1

You sure move fast, Tony. I can't wait to see how the MS+Turbo setup works for you.

Yup. T04E with a 54 trim was my first choice, but I got this one for next to nothing.

Tony, how much boost do you plan on running?

My external wastegate currently has a 5psi spring on it, so that is where I am going to start, but I guess Hp is like a drug and you always want more.

For now I want to keep away from the added complexities of an intercooler, so I'm gonna stay below 7psi.

Calculations show that 7psi (with no intercooler) is good for another 50Hp. Intake temperatures rise by 50C.

If you add an intercooler with 70% eff you get 75Hp gain at same boost with a intake temperature rise of only 15C. So there is something to be said about adding an intercooler.

I plotted out the maps so you can see the differences. This is assuming a 3.0L motor. The flow points are for;
2500 rpm - 5lbs of boost
3000 rpm - 7 " " "
3500 rpm - 7 " " "
4000 rpm - 7 " " "
5000 rpm - 7 " " "
6000 rpm - 7 " " "

The T04B-V
http://forums.pelicanparts.com/uploa...1080275083.jpg

The T04E-57
http://forums.pelicanparts.com/uploa...1080275142.jpg

I think you are going to end up running more than 7lbs and that will push the plots upward on the maps.

Who else thinks NATCHAMP "lives" at Holiday Inn Express?

You guys always find ways to make me feel dumb.

I look at that graph and see a piece of wood fashioned into a propellor blade.

Actually, it looked like a jai-lai (sp?) stick where the ball is propelled over 100 mph!


Sorry for the dry humor. I have been following TBITZ thread just waiting for reviews, hp gains, etc.

I also am building a turbo at the present, thus subscribing to this thread also.

I plotted my estimated boost curve on all the garett turbos and T04E-54 was the best fit. I just happen to come across this T04B-V for dirt cheap so I bought it. I would love to start with a new T04E-54 from the get go, but my financial situation doesn't allow it :(

Anyone got one lying around that can donate to the R&D effort? :)

LOL, well they do give me a discount. Plus, the good news I just saved a ton of money by switching to Gieco ;)

Gieco eh?

Where do you get your turbo's from? I've looked at turbonetics and the T04E is listed for about $850US.

The older Garrett stuff is all over ebay, you might keep your eye open for a bargain. Honestly, I think your 7lbs boost will last as long as your first ride, then you will want more.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2469420857&category=33 742

You should also consider a T3/T4 hybrid for quicker spool up.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2468319675&category=33 742

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2468804659&category=33 742

here is another source but I have never bought from them:
http://www.turbocalculator.com/sale-garrett.php#t3-t04e

Thanks for the links Mark.

Anyone have compressor curves for the GT series turbos?

http://project911.luminasweden.com/garrettcatalog.pdf

Looking at the GT compressor curves i t seems like they've been designed to run most efficient at higher boost levels. The closest fit looks like a GT-32, but for mild boost (7-10psi) the T04E-54 still looks like a better choice.

I don't know how much better the GT turbines are compared to the T04E turbines. They do mention in the document they've eliminated the "on-center" housing for GT series because it is very ineffecient (this is what I have and is what was used on the BAE kit):(

" On-center turbine housings refer
to an outdated style of turbine housing with a centered turbine
inlet pad. The inlet pad is centered on the turbo’s axis of rotation
instead of being tangentially located. Using an on-center housing
will significantly lower the turbine’s efficiency. This results in
increased turbo lag, more backpressure, lower engine volumetric
efficiency, and less overall engine power. No Garrett OEM’s use
on-center housings."

If you check efficiency numbers you'll see that GT's are almost into 80% while T04 is hovering around 73-74% in the middle of the "island". So in real world, GT's are probably at least as efficient as TD's @ low boost and much more efficient at high.

I'm planing to buy a GT32 and fabricate adapter between our headers (made for GT40) so we can switch between turbos and find optimal one.