Newbie question and asking opinions

[kpick]

Hello all and thanks for a great forum with tons of well informed people.

I'm very new to the forum and have killed more evenings reading and learning than I care to admit.

I'm looking to build a type 1 EFI and Turbo motor for a very streetable ride.

The key for me is the word "Streetable". I'm happy to give up some performance for cool running reliability.

I'd be very pleased with 200hp. I'm looking to buy a mostly complete engine then massaging the EFI and turbo work.
I'm assuming I will need to keep the compression down to 8psi at most.

I'm looking at this motor now and would like to get an opinions if this would be a good starting point.


Here are the specifications on the motor:
2074 cc's

Bugpack forged counterweighted 78mm crankshaft (the old 4340 forged which was made in the USA), Scat 5.5 H-Beam connecting rods, AS41 full flow .020 mains, Mahle 92s, CB 044 Magnum round port 42x37.5, 8.5:1cr, Engle W140 camshaft designed for 1.1 or 1.25 rockers, and it's specs are .419" Cam Lift, .460" Valve Lift (1.1 Rockers), 313 degrees of advertised duration, and 274 degrees of duration at .050", on a 108 Lobe Center, lightened flywheel, chromoly push-rods, Bosch 009 with electronic ignition (no points).


Thanks in advance for any guidance and please allow many more questions.
K.

[madmike]

That's a huge cam for turbo for street
try to find a cam less then 300*
40X35.5 heads will work for you too

[kpick]

Thank you Mike.

Do you think 8.5 is a safe compression rating?

K.

[madmike]

Yes

[turbobaja]

Is this a motor you already have or one you're thinking about buying?

Either way, its not even close to what you want. Needs a full teardown to swap cams and do NOT run cima 92mm pistons/cylinders on a boosted engine. AA thickwall 92mm cylinders would work.

"Safe" compression is 100% dependant on what cam you end up running, what fuel, how much boost, how hard will it have to work? Heavy bus, light buggy, what's it going in??

[The Newf]

I suggest a milder cam like fk-8 with 1.4 rockers,keep cr to 8:1.Ditto on the AA cylinders.Boost away.

[kpick]

This is a motor I was looking at buying. I'm hoping to find a mostly built motor then add efI / turbo.

From the advice here, looks like I should "keep searching".

The engine is going in a 1967 912 Porsche I recently inherited. The car is in good shape without a motor.

I've been reading as much as possible and trying to decide type 1 or type 4. I want to run pump gas, low boost and just build a cool running daily driver. 200 HP would be my idea but I'd give some up for reliable and streetable.

Again...thanks for the input.
K

[petew]

Umm, this is a slightly offbeat alternative... and I might be speaking out of line but...

Isn't the stock 912 motor a pretty sweet unit as is? They came in a 2.0 litre right? Why not just add EFI and a turbo to that? Save you a stack of cash right off. If you're worried about the pistons, you could pull your heads off and fit forged ones, but I'm guessing the factory stuff would be pretty awesome as is.

Hide the turbo under the car and use a water/air intercooler. Don't annoy the purists, confuse them.

[kpick]

Petew,

The early 912's came with a 1700 cc motor. They are a bit week at 90hp. The later (1976 912's) came with the t4 2.0. My car was an inheritance that came without a motor.

However, your suggestion was exactly what I came to. I just picked up a T4 1.7 from a Porsche 914.

Now I need to build a mild EFI/turbo motor. I'll be asking a lot of questions.

Look for a thread titled "Crowed sourcing a t4 turbo build"

thanks all,
k.

[petew]

AWESOME! Looking forward to it.

"Crowd sourcing" LOL Good luck with that.

[slowsixtyduece]

You are heading in the right direction by taking the time to ask questions. If you are lookin for something already half built, there is a 2276 longblock that was built for turbo in mind on thesamba right now:
http://www.thesamba.com/vw/classifieds/ ... id=1798509

Not mine, but looks like a pretty decent deal for a streetable long block. May be a tad Over the top for what you are looking for but it leaves room to grow. And it's better than buyin a n/a motor and having to tear it down to replace a cam, lower compression , etc.

For a street able turbo efi motor, look or build something with a cam no more than 260 duration @.050/ 300 degrees full duration, and possibly on a wider lobe center separation depending on your taste in how the power comes on. It sounds like your desires are quite close to mine although I'm hoping eek out around 230-250 on low boost.

You won't be needing huge ported heads or large valves (42x37 is the biggest id think about going) but a head that keeps up with the cfm you want to push through the motor. I had shag port my street heads and I went with a 40x37 valve. They are the AA 501 casting so try should cool close to a stock head.

As Karl noted, compression will depend on numerous variables. I went with around 8:1, but I'm at altitude and will not being doing huge amounts of boost. Plus I plan on water meth injection too if needed.

Turbo sizing will be another factor. A lot of guys run somewhere within the vacinity of a t-3 or t3/4 hybrid, but once you determine a cam and heads and power range, a turbo guru can help you with turbo trims, etc.

Do you know what efi setup you will be running ? Have you tuned an efi turbo car before? Just curious.

My goal is to have a lot of torque (torque is ideally fun especially after having a higher strung n/a motor) and be able to keep it running for a while between tear downs. I swear, I have done 4x more reading on all of this than the amount of time I have into building my motor. But I only wanted to do it once and wanted to do it right the first time. Two motors I really modeled my 2276 from was Scott Featherolfs/ turbobug56s motor (2276, tcs 10 cam, efficient n/a heads, t3/4 turbo, 10 second car shifting at relatively low rpms) and bob hemphills/turbobobs motor (2276, engle v-26 cam, ported heads, t-3 turbo, 11 sec car).

Both cars had loads of bottom end torque and neither of them were afraid to drive their cars on a regular commute. I always loved watching their cars run/ race back in the day. If you have a moment, do a search and listen to their opinions.

Anyhow, good luck!

[slowsixtyduece]

Also, for a street car I dont think you need much more lift than .500-.550" at the valve. Also, take a look at Mario Vellotas old motor; 2276, turbo efi, cb cnc heads (42x37), engle v-26 cam, etc. In fact, if I recall correctly, turbobajas motor (from a post above) is similar and even more potent. Maybe he can chime in with his specs and so on?

All that to say, these guys have really paved the way in terms of r and d for what an efficient and effective turbo vw motor looks like! For those of us coming later, it allows us to not have to shoot in the dark on what works and what doesn't