Supercharger Kit for 914 (fact or fiction)

[joncdeke]

Does anyone know if such a kit really exists?
I've been searching for some time now but to no avail. Thanks!

[joncdeke]

I just read Jim Osborn's post from awhile back, which stated the following: I have talked to several supercharger companies and they said they would do custom one off runs for about 4-5K. I'm assuming if there were more than one or two people getting it done it would be considerably cheaper. Any takers on this adventure?

Jim,

Did you get taker's on this?

Thanks!

[Rich Hilgersom]

Was fact.. now fiction.
There was a Florida company who made a roots blower fit a 914. They stopped after just a few units. It was a very low boost system for a mild setup.

I'm still working on a Vortech supercharger setup as a one off. The current plan is to use a CB performance FI which can be purchaced off the shelf with a pressure manifold, a FAT 911 fan shroud with a dual pulley, and a VORTECH V-5 G-TRIM http://www.vortechsuperchargers.com/units/
I have SCAT type 4 split port heads already so the big issue of the head not being able to handle the power is gone.
The only custom item is going to be the supercharger bracket to mount above the fan shroud next to the fan.
Email me if you want the details.
-Rich

[oredith]

there are no kits available for ANY kind of force induction for the 914, as far as *I*'m aware of..
I've not heard of any owner that's actually done a supercharged 914. turbo charging though, there are *some* help. Sam G. has done a carbed, pull through turbo setup. Ed V. from rennlist just finished up a CIS push-through setup on a 1.8?(might be a 1.7, not positive).. and i'm working on a push-through system using the stock FI on a 2.0

Jeff

[Blu Flag Chicane]

Oredith,

I've talked with Ed about this to some length and I want to do the same to my 2.0 with stock FI. If you have any links or tips you can share I'd like to read them. I'll be pursuing this more as the car gets closer to being turbo ready.

thx,

-BFC

[roadtrp204]

European Car had an article a few years back on a guy who turbocharged the stock FI. At the time of the article he reported some problems with the system leaning out and retarding the timing under boost. I'll see it I can find the issue and give better details.
Chris

[oredith]

when i said "stock fi".. i meant "stock fi" plus a bit of tinkering.. i'm planning on welding my own pipe that would attach on top of the throttle body. the pipe would house 2 additional injectors that are hooked up to pressure switches.. one that kicks on at 3-4 psi, and the other kicking on at 7ish.. another alternative i've been tinkering with is having a variable pressure switch that would gradually up the fuel delivered by the additional injectors as boost increases.. but i haven't figured out if the stock fuel pump will be able to handle a single, larger, injector.. maybe if i hook that variable switch up to 2 normal injectors..
it's all just on paper right now.. i've got my spare engine to test all these possiblities on, unless i blow that one on the first try..
the good news is that i found a muffler shop near work so i was actually able to pick up muffler flanges during lunch. now i can finally go on with my header fabrication... i'll keep the board posted once i get to the testing stages..

Jeff

[Dave at Pelican Parts]

Jeff, a few more things to think about with your two extra injectors.

First, what kind of injector are they going to be? The "regular" injectors are built to atomize some fuel pretty well, but they are designed to be "pulsed". If you can rig up some kind of "pulsator" circuit based on boost pressure, you might be able to get away with just using one extra injector, and varying the duty cycle. This is the same way the regular injectors work. That would let you pretty much continuously vary the amount of fuel going in, rather than just two extra steps. But it is more complex...

You can use a cold-start valve, which is designed for more continuous operation. But the downside is that it doesn't atomize the fuel all that well.

The next consideration has to do with the atomized fuel. Even if you get it well-atomized, some will precipitate out when it hits the throttle plate. If the extra injector(s) are in front of the throttle plate, you will get this happening. In addition, more will precipitate out in the manifold before the fuel gets out to the heads. I'm not sure how evenly the fuel would be distributed to the cylinders--it's not as critical with the CSV, which is already in the manifold, since that only operates while the starter motor is spinning. It's just there to help the motor get that initial kick-over.

I'm not saying it can't be done. I'm just trying to bring up some extra things to think about. You might try running a test. Perhaps you can ground the thermo-time switch to force the CSV on while the starter is cranking. Crank for some specific period of time, with a separate flask or some such directly under each exhaust port. That should give you an idea if the fuel gets more or less evenly distributed. It's very imprecise, but what the heck.

Hmm, the atomization may not be that critical after all. The air will be heated by the turbo, and hot air will turn the fuel droplets into fuel vapor easier. Sort of like the pre-heaters on VW Bug carbs.

Just some random thoughts for you...

--DD

[oredith]

well, the thought on having the injectors kick in at specific points is that unlike the variable one, the additional injectors wouldn't be working until i'm under boost, and i won't be under boost unless the throttle plate's open.. yes, a chunk of that's going to get on the plate, but i was hoping there would be enough to go around still... like i said, all on paper right now.. i'll really have to test it to determine if it'll work or not. i might even make my own intake manifold.. the flatness of the stock one doesn't seem to be the most efficient way to get fuel *evenly* to all four cyl.

[sammyg2]

With 7 psi of warm air rushing through the manifold, the fuel will get atomized, and it will get to the cylinders. I agree with Dave about the injectors. I recommend using the cold start injectors, or maybe even some off of a CIS system. I believe Ed V. has done that, might be worth asking him what kind of extra injector he uses, if any. If the extra injectors only kick in at wide open, full throttle boost conditions, I really don't think atomization of distribution will be a problem. At idle it would be, but not under boost. Even with an intercooler the air will still be plenty warm, so the fuel will mix well.



------------------
Gerald Gore II (Sam)
73 914 350 small block

[joncdeke]

Just curious... Almost everything that I have read indicates that Supercharging is a easier and better way to go, vs turbocharging. There doesn't appear to be kits available for neither one but the vast majority of guys are going Turbo... Why?

Thanks!

[Jim Osborn]

Well I never went through with it because I went out and bought a new car. A Turocharged VW Jetta. I chipped it and put exhaust on it, I have now satisfied my longing for boost. Now I'm considering a V8 for the 14. It's all up in the air right now, I probably won't be doing anything for a while at least until I get out of school. Sorry to get your hope up. Rich Hilgersome was working on a kit in his head, he was talking about putting the blower where the factory AC compressor was. That seemed like the most thought out plan so far.

[Blu Flag Chicane]

I don't want to speak for Ed V. but from what he told me he converted his entire engine to CIS and it's able to handle the amount of boost he's generating without the need for extra injectors.

As for the turbo vs supercharger question, oye you should've been on the 911 rennlist a few weeks ago. Coming from a background of both I'll say that turbo's are more entrenched in the automotive marketplace than superchargers and are therefore cheaper to buy/fix/replace. Secondly, for custom applications like these, you can't beat a turbo for flexibility. A turbo's wastegate can be controlled by a bleed valve or electronic boost controller to compensate for ambient temperature or other factors. With a supercharger the only thing that will change its output is to have a new pulley machined. There are at least a dozen other reasons but I'll leave it at that

-BFC

[campbellcj]

You also need to belt-drive most/all superchargers, which seriously limits your installation flexibility. I am not even sure you'd have a good mounting point on a 914. With a turbo, your whole exhaust system will be custom fabricated anyway, and so you can position the turbo where you want it, with no need to be in the same plane as the belt drive.

[joncdeke]

Thank-you all for taking the time to answer my questions! There are certainly many options out when it comes to propelling our beloved 914s... I think my next project might be a big four, a Pauter four, a six! or even an eight (928)!!! Or maybe I'll just keep things as they are and stop asking dumb questions! No... that would be to easy.

Thanks Again!

Jon

[oredith]

well.. a pauter-4's expensive.. maybe even as expensive as a cheaper -6 conversion, it definitely gives you a stronger base to build a force induction motor though.. the 918 (928) is being investigated by Rich.. (BTW, how IS that going?) and looks to have a lot of potential.. and will still allow the car to run in a class in PCA races (porsche motor). from the pictures i've seen of the work in progress though, it's not for the weak-hearted when it comes to taking a saw to your car.

there's the CW's of 914's.. and i think there's the rest of "us". I, for one, don't know when, if ever, i'll be satisfied with my 914.. When i get done with the turbo install, i'll be happy for a while, but i know it won't last long.. soon it'll be 911 front end, bigger+stickier tires, LSD, etc..
that's the fun of having a "project car"..

[sammyg2]

For the do it yourselfer, turbos are actually easier and cheaper.
Case4 in point: how many "good" superchargers can you find in the junkyard that are sized correctly for the 914 engine?

Used turbos are available for about $100 each. The material for the piping is real chap, and if you can weld, not all that hard to put together.
I'm not saying there is anything wrong with superchargers, I was running a mooneyham blower long before I new how to spell turbo. They are just easier and cheaper, imo.

[AlexO]

So where would one mount the turbo to keep the plumbing short? Would a twin turbo setup be possible, putting each turbo on the side of its respective bank? Seems like an easier way to go but what would the difference be in turbo lag, or are our motors just plain too small....
--Alex
-'74 2.0

[oredith]

I'm planning on mounting my turbo where the battery used to be (relocating it to the rear trunk). the "shortest" tube location would be underneath the rear trunk, hanging "under" the car, but after fiddling around with the turbo under the car, i came to the conclusion that the turbo is just too big (this is a tiny chrysler 2.2 turbo, too) to fit in that space without some *messaging* of the rear trunk floor..

a twin turbo is probably do-able, but why?.. the car's got enough on its hands just by pushing one small turbo.. if it was to be done, it'd have to be 2 VERY tiny turbos.. and the result wouldn't be much to brag about... stick with a single turbo.. they're cheap, and easy.. after i'm done with my current moving situation, i plan to have the hardware all assembled and ready for testing in about a month and half.. and from current calculation, the cost will come in well under 500 dollars (you'll have to do your own welding, of course)

Jeff

[racejoe]

Do you have to "tune" the exhaust lengths before the turbo to give as close to constant pressure at the turbo?