turbo charging a 3.2 - question for all turbo goru's...

[Mike the mechanic]

Rick, you don't think a bolt on set-up can yeild excellent results? Have you seen my launch mpeg? If you haven't, let me tell you about it... stock 3.2 internals, never opened up, 10 psi bolt on system = close to 400 flywheel hp and 0-60 in the very low 4's.

Then again, "high horsepower" is a relative term.

[turbo6bar]

Mike, what size turbos would you recommend for the 3.0SC? Prefer non ball-bearing to keep cost reasonable. The GT-series look incredible, but $$$.

I am just dreaming, but I always wonder what a 3.0 with 5-7psi would net. Mainly interested in mid-range kick, and not top-end power. I figure the $800 for a set of SSIs would go a long way towards a new turbo. Oh, and if the turbo ever became reality, the CIS would be replaced with EFI.

Jurgen

[rick conrath]

I did say high horsepower numbers and your talking 10 psi not 5. I just think going through the effort to do the exhaust and turbo setup needs to be balanced against the benefit. Those are impressive results on your 3.2...so it's probably worth it to you. Someone else running 5psi might be disapointed in the end if they were expecting the 400 hp threshold. It's just a battle against the basic laws of physics trying to keep an EFI 3.2 motor together in a turbo application without changing internals. Now let's talk about the additional cost for an intercooler, boost controller,wastegate,twin plug, fuel enrichment......
Rick
'78 930

[Joeaksa]

20 years ago I turbo'ed a Volvo 242GT, two years before the factory came out with a turbo. Used an aircraft turbo and external waste gate. Kept the innards on the motor stock and kept the boost down and the motor lasted over 130k miles. Overhauled the turbo twice in that time but motor needed nothing but routine maintenance.

Thing was a hoot and kick in the pants but up at altitude in the mountains it would walk away from everything in sight except another turbo. If you kept the boost down the motor will usually last but nothing is guaranteed in life. My car ended up totaled in a accident when someone ran a stop light, otherwise believe it would still be running today.

Joe

[lendaddy]

If you are not REALLY into this kind of thing, leave it alone! My brother is like these guys who love reading about, learning, designing, and programming these setups. They live for it. If you put ANY value on your time forget it, you will lose. But if you are not on a time table and love the challenge this can be an awesome project with stunning results. You really cant imagine how much time the true "trailblazers" have put in to their systems. Having the time is one thing, enjoying the process is another. Just MHO

[Natchamp]

Ditto lendaddy. It's a sickness. I call it therapy.

[rfng]

5 psi on a 3.2 requires probably 17-20 lbs of air per hour without an intercooler. You need to get the compressor map to determine which compressor you want to use. You should shoot for at least 70% efficiency for the compressor. At 10 psi with an intercooler you'll need around 30-34 lbs of air per hour.

Then you have to figure out what rpm you want it to start spooling up and select your a/r (controls inlet pressure to turbine), then how much top end power you want or need is done with the turbine trim-however as the trim get bigger you will lose some bottom end.

But whatever choice you make it will always be a compromise. Lots of bottom end, there will be no top end power, lots of top end, no bottom end. But its all relative, how much does it take to thrill yourself.

However, boost is like a drug, it may seem fast for the 1st couple of months, but with all the money your gonna be spending you want at least 7-10 psi at the minimum to give you that violent rush, its take a minimum of 9 or a rise of 3 points of compression to really feel the difference/rush. I think you'll be disappointed with only 5 psi, quick but not violent which everyone expects from a turbo.

You see every 3 psi is suppose to be the equivalent of 1 point of compression, dynamically of course. However it will yeild slightly more horsepower than its normally aspirated counterpart, as the increase in manifold pressure increases the engine efficiency(essentially allowing more air and fuel to packed into the cylinder). More fuel and air in the equivalent space=bigger explosion creating more energy being applied against the piston forcing it to move faster.

So 5 psi will only yield the approximate equivalent of 10.6-10.7 to 1 compression. The greatest yield you get with 5 psi is the increase in torque which is also horsepower, but you wont get the rush that a stock 930 gets because your not raising the dynamic compression enough.

A Stock 930 under dynamic compression jumps the effective rate from 6.5/7.0 up to 10.5-11.0 to 1 compression (a 4 point rise) or for those whose have move it up to 15 psi your increasing the compression by 5 points. That why everyone who put in the 1 bar spring say the car really comes alive.

Plan on going at least 9 psi which with give you an increase of 3 points dynamically, which is the minimum for a violent ride. 16 psi about the maximum you'll be able to run with your stock compression on the street. However as stated this will require extensive modification to your fuel and ignition system to get it to run with any longetivity. But the jump from 7 to 9 will only cost you about 2K more at a retail level as your fueling system and ignition system will only require marginal tinkering.

Hope this helps.

[bell]

very interesting stuff well than how about 2 garrett TD-03's i've haven't played with anything larger than a 2.5 with my dodges, but see many points......great thread

[dickster]

You want specifics on turbo choice? Just ask.

mike, i'm asking what modern turbo would fit the bill (full specifics please!!) - anything i can get off a production car? 5psi non intercooled (intercooled later).

beep beep,

i'm no expert but i've read a few books on the subject, by guys that have built their own systems (and customers systems). thats what got me thinking about doing a simple install. i don't wanna get $$$$ed into fuel and ignition problems.

can i have that turbo??

rick,

i dont want big hp (yet!). around 300hp will do for now. if i get into it later than i can develop the system more.

bell,

i thought of twins. one of the books gave advice on turbo sizing and said that a good 1.8 turbo production car should provide suitable sized turbos for a twin setup on a 3.2. that way i could find a couple of cheap secondhand units. it also suggested that for best results six cylinder motors should always use twins.

my problem (apart from no cash) is that i haven't got time/skill to fab all the pipework - i can weld, but it wouldn't look pretty - thats why i was thinking of the 930 pipework. perhaps i could start with that, and modify it..........

[Ceder2.4S]

Hi
Try this link out: www.gikturbo.se . They have a kit for 911 CIS. The price is ca. 1100£. The site is in Swedish. But you can send them an email and ask what’s in the set.

Carsten

[dickster]

thanks i've emailed them. i hope their english is better than my swedish!

[beepbeep]

Originally posted by Mike the mechanic
Now that is an awesome turbo; Garrett's latest technology= super effecient, super flexible and super durable. Is that yours beepbeep?

Yupp , It's going to be bolted onto our 2.3L fourbanger. It won't have much to say below 3500 revs (altough it's "ported shroud" -design helps) but according to compressor maps it will scream at top-end.

dickster:

3.2 engine is nice, but i think its better idea to do it right from the beggining. That means shaved or new pistons, bigger injectors, fairly sized turbo and ~10 psi of boost.

Twin-turbo setup has inherently less lag but is also more complicated when it comes to pipework.

[FIN911]

"There is no such thing as cheap and easy turbocharging. "
Hmmm... I made my own setup, based on my 3.5l N/A engine, couple of months ago. I bought Chip and fuel pressure regulator from Protomotive (thanks Todd!). Turbo is rebuilted Garret T04B.

..and the result:
~24h welding and fitting...
~2500$!
336FWHP (chassis dyno 296RWHP) 0.4 bar of boost


Cheap? Yes!... Easy?...maybe, if you like welding
-kalle

[dickster]

Twin-turbo setup has inherently less lag but is also more complicated when it comes to pipework.

thats what put me off (pipework).

I bought Chip and fuel pressure regulator from Protomotive (thanks Todd!).

kalle

thats interesting 'cause i thought he didnt like selling just parts. i've emailed him........

so you built yours from scratch? got details/pics. would love more info.

[tsuter]

Turbo it!
911SC Turbo

[dickster]

tsuter,

i'm working on it! just ordered another book.

i believe a 3.2 with motronic running 5psi would be more simple than even yours.

i think i can install a boost controlled fuel press reg. and get away without any further fuel or ignition/timing changes.

[1fastredsc]

Out of curiosity, what is that new garrett you guys are talking about, i occasionally read science/mechanics type magazines but haven't seen that one. What makes it more durable and better like you guys are describing? And don't hold back on details, i've delt with turbo's before so i'm not a newbie.

[WERK I]

I'm with Rick. Turbocharging a NA engine without modifying the internals is asking for a short lived engine. 3.2's use a cast piston which would crack under the slightest hint of detonation or even tolerate the extreme temperatures the turbo engine works under. Just my $.02.